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  • Articles  (2,723)
  • 2010-2014
  • 1980-1984  (2,723)
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  • Electrical Engineering, Measurement and Control Technology  (2,723)
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  • Articles  (2,723)
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  • 2010-2014
  • 1980-1984  (2,723)
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  • 1
    Electronic Resource
    Electronic Resource
    The influence of electrode macroscopic curvature upon surface roughness effects in compressed SF6 (1980)
    Springer
    Electrical engineering 62 (1980), S. 43-49 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Bei den bisherigen theoretischen Untersuchungen der Oberflächenrauhigkeitseffektc in komprimiertem SF6 wurde die makroskopische Krümmung der Elektroden nicht berücksichtigt. Die Vernachlässigung dieses Parameters kann zu falschen Schlußfolgerungen über die Existenz einer unteren Schranke für die Einwirkung der Oberflächenrauhigkeit auf die Isolationsfestigkeit leiten. Das Problem wird hier untersucht durch Anwendung eines aus sich schneidenden Kugeln bestehenden Modells auf den Durchschlag in komprimiertem SF6. Aus den Ergebnissen geht hervor, daß es keine untere Schranke bei praktischen Systemen gibt; daraus folgt, daß die Oberflächenrauhigkeit immer eine Reduktion der Isolationsfestigkeit bewirkt.
    Notes: Contents Previous theoretical studies of electrode surface roughness effects in compressed SF6 have not included the macroscopic curvature of the electrode in the analyses. The omission of this parameter can lead to erroneous conclusions regarding the existence of a lower limit to the effect of surface roughness upon insulation strength. This aspect is examined through the application of an intersecting sphere model to the breakdown of compressed SF6. The results indicate that, in a practical system, no lower limit exists and consequently electrode surface roughness will always lead to a reduction in the insulation strength.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01578116
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of homogeneous magnetic field in internal region of cylindrical solenoid (1980)
    Springer
    Electrical engineering 62 (1980), S. 75-79 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The paper describes a method of synthesis of a magnetic field in the three-dimensional region lying inside a cylindrical solenoid. The application of the method is demonstrated by the example of a synthesis of a homogeneous field. A regularization method of ill-posed problems has been employed for the solution of the problem.
    Notes: Übersicht Es wird eine Methode zur Synthese des Magnetfeldes im dreidimensionalen Bereich innerhalb einer zylindrischen Spule beschrieben. Die Anwendung der Methode wird am Beispiel der Synthese eines homogenen Feldes demonstriert. Zur Lösung des Problems wird eine Regularisations-Methode benützt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01578636
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  • 3
    Electronic Resource
    Electronic Resource
    Permeables Rotationsellipsoid mit Meßwindung im Felde achsenparalleler Leiter (1980)
    Springer
    Electrical engineering 62 (1980), S. 63-73 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents Induced voltage in the test-coil mentioned above is determined using potential theory. The exciting plane field can be expressed as a simple series in oblate spheroidal coordinates. As a result the expression for the induced voltage is also a simple series. The calculation of the induced voltage for practically significant cases can, however, be simplified by an approximating expression that can be calculated very fast on a pocket-calculator. The voltage rise in the coil caused by the permeable spheroid is also given. The general expressions obtained are verified using the closed form solution for a high permeable sphere. Finally, the resultant plane field inside the spheroid is also given in the form of field plots.
    Notes: Übersicht Mit Hilfe der Potentialtheorie wird die Spannung bestimmt, die in der in der Überschrift genannten Windung induziert wird. Da das ebene erregende Feld in den verwendeten Koordinaten des abgeplaiteten Rotationsellipsoids durch eine Einfachsumme darstellbar ist, erhält man für die induzierte Spannung ebenfalls eine Summendarstellung. Diese läßt sich jedoch für die praktisch interessierenden Fälle durch eine einfache geschlossene Näherungsbeziehung ausdrücken, die mit einem kleinen Taschencomputer ausgewertet werden kann. Die durch den permeablen Körper hervorgerufenen Spannungsüberhöhungen werden angegeben. Die allgemeinen Ergebnisse werden an Hand des geschlossen losbaren Sonderfalles einer hochpermeablen Kugel kontrolliert. Abschließend wird noch das Feldbild des sich innerhalb des permeablen Rotationsellipsoids einstellenden resultierenden ebenen Feldes angegeben.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01578635
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  • 4
    Electronic Resource
    Electronic Resource
    Magnetic field synthesis at the plane perpendicular to the axis of a solenoid (1980)
    Springer
    Electrical engineering 62 (1980), S. 153-156 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Die vorliegende Arbeit beschreibt die Synthese des magnetischen Feldes in der Fläche normal zur Achse einer Spule.
    Notes: Contents The paper deals with the synthesis of magnetic field in the plane perpendicular to the axis of a solenoid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01579899
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  • 5
    Electronic Resource
    Electronic Resource
    Das Feld einer exzentrisch gelegenen Zylinderspule zwischen zylindrischen Polen endlicher Permeabilität (1980)
    Springer
    Electrical engineering 62 (1980), S. 157-165 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents A spatial cylindrical ciol with an arbitrary time dependent current flowing through in, is brought into the gap between two magnetic poles of finite permeability and is moved along an arbitrary path in a plane perpendicular to the axis of the cylinders. A spatial test-coil is wound on the poles and the voltage induced in this coil is to be determined. For this, the field due to an eccentrically located cylindrical coil in the gap between two cylinders of finite permeability has to be calculated. The paper under discusson gives an analytic solution of this spatial boundary value problem. Further, a general expression for the mutual inductance of the two cylindrical coils mentioned above is developed and anlytically verified.
    Notes: Übersicht Im Spaltraum zwischen zwei zylindrischen Polen endlicher Permeabilität wird eine räumliche Zylinderspule, die von einem zeitlich beliebig veränderlichen Strom durchflossen wird, auf einer beliebigen Bahnkurve senkrecht zur Zylinderachse bewegt. Bestimmt wird die induzierte Spannung in einer räumlichen zylindrischen Meßwicklung, die auf den Polen angeorden, ist. Dazu muß das feld einer Zylinderspule bestimmt werden, die im Spalt zwischen zwei Zylindern endlicher Permeabilität exzentrisch angeordnet ist. Eine analytische Lösung des vorliegenden räumlichen Randwertproblems wird angegeben. Weiterhin wird eine allgemeine Beziehung für die Gegeninduktivität zwischen den beiden genannten Zylinderspulen aufgestellt und analytisch kontrolliert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01579900
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  • 6
    Electronic Resource
    Electronic Resource
    Analyse der Ausgangsspannung des gesteuert betriebenen Direktumrichters mit Hilfe von Ortskurven (1980)
    Springer
    Electrical engineering 62 (1980), S. 167-175 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The output voltage of the open loop controlled cycloconverter can be represented as a Fourier series for all fractional rational ratios output frequency to input frequency (ω A /ω E ). In the general case the frequencies of all harmonics are integer multiples of the subharmonic frequency ω A / n ,n being and integer depending on ω A /ω E . At definite relative big values of ω A /ω E harmonics, the frequency of which lies near the rated frequency ω A , reach remarkable amplitude weight. The consequence of the superposition of this harmonics and the wanted component is a distorting beat effect with the beat frequency |ω H −ω A | in the output voltage of the cycloconverter. A suitable mathematical description of this effect can be found by representing the output voltage in a complex system of coordinates, which is rotating with ω A . The imaginary and the real component of this complex transformed output voltage can be formed with electronic circuits in the real plant to realize a control system for removing or reducing the beat effect. An exact knowledge of the cause of this beat phenomenon is necessary to be able to design this control system
    Notes: Übersicht Die Ausgangsspannung des gesteuert betriebenen Direktumrichters kann man für alle gebrochen rationalen Verhältnisse Ausgangsfrequenz zu Eingangsfrequenz (ω A /ω E ) als Fourierreihe darstellen. Die Frequenzen aller Harmonischen sind im allgemeinen Fall ganzzahlige Vielfache der Frequenz ω A / n einer Subharmonischen, wobein eine von ω A /ω E abhängige ganze Zahl ist. Bei bestimmten relativ großen Werten von ω A /ω E erreichen Harmonische, deren Frequenz ω H in der Nähe der Sollfrequenz ω A liegt, beachtliches Amplitudengewicht. Als Folge der Überlagerung dieser Harmonischen mit der Sollkomponente stellt sich in der Ausgangsspannung des Direktumrichters ein störender Schwebungseffekt mit der Schwebungsfrequenz |ω H −ω A | ein. Eine geeignete mathematische Beschreibung dieses Vorgangs ergibt sich durch die Darstellung der Ausgansspannung in einem komplexen mit ω A umlaufenden Koordinatensystem. Realteil und Imaginärteil dicser komplexen transformierten Ausgangsspannung können an der realen Anlage mit elcktronischen Mitteln gebildet und für eine Regelung zur Beseitigung oder Reduktion des Schwebungseifekts benutzt werden. Der Aufbau dieser Regelung setzudie genaue Kenntnis über die Entstehung dieser Vorgänge voraus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01579901
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  • 7
    Electronic Resource
    Electronic Resource
    Bemessungsregeln für Transformatoren (1980)
    Springer
    Electrical engineering 62 (1980), S. 187-194 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The purpose of this paper is not to deal with individual transformer designs rather the mathematical formulation of universally applicable principles. It should thereby contribute to an understanding of the fundamental correlations between the important parameters. The first part treats an easily calculable idealized type, the ring-transformer, a second part the usual transformer-types.
    Notes: Übersicht Diese Arbeit behandelt nicht die Berechnung von Transformatoren im einzelnen, sondern die mathematische Formulierung allgemeiner Gesetzmäßigkeiten. Sie soll damit zum Verständnis der grundsätzlichen Zusammenhänge zwischen den maßgebenden Größen beitragen. Der erste Teil untersucht eine einfach berechenbare idealisierte Bauform, den Ringtransformator, ein zweiter Teil die gebräuchlichen Transformatortypen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01570947
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  • 8
    Electronic Resource
    Electronic Resource
    Ein Beitrag zur inhomogenen Leitung (1980)
    Springer
    Electrical engineering 62 (1980), S. 219-224 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The wave propagation along a lossless two wire transmission line with variable inductance and capacity per unit length is investigated. Exact representations of the solutions are found in closed form provided that the variations of the characteristic impedance are described by a class of functions which are either monotonically increasing or decreasing.
    Notes: Übersicht Die Wellenausbreitung auf verlustlosen Doppelleitungen mit räumlich veränderlichen Werten der längenbezogenen Induktivität und Kapazität wird untersucht. Für eine Klasse von entweder monoton wachsenden oder monoton fallenden Verläufen des Wellenwiderstandes gelingt es, exakte Lösungen in geschlossener Form darzustellen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01570951
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  • 9
    Electronic Resource
    Electronic Resource
    Electrodynamics of a resistive sheet moving inside a wave-guide (1980)
    Springer
    Electrical engineering 62 (1980), S. 225-232 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Die Wechselwirkung zwischen einer Leitungs-welle und einer gleitenden Metallscheibe wird untersucht. Das elektromagnetische Feld wird ermittelt an Hand der Lorentz Transformation sowohl wie an Hand der Hertz und Fitzgerald Superpotentialen.
    Notes: Contents The interaction between a guided wave and a gliding metal sheet is investigated. The Hertz and Fitzgerald superpotentials are resorted to along with the Lorentz transformation and the overall electromagnetic field is obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01570952
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  • 10
    Electronic Resource
    Electronic Resource
    Die Berechnunǵ von Blitzüberspannunǵen an elektrischen Anlaǵen mit Keilwellen (1980)
    Springer
    Electrical engineering 62 (1980), S. 255-264 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents Lightning strokes onto overhead lines cause overvoltages in the connected electric systems, propagating as traveling waves. For estimations of these overvoltages a simple method is developped in this paper. Applying ramp functions and using traveling wave methods simple formulae are derived, applicable with a good accuracy. The influence of lightning arresters protecting the systems against the overvoltages is taken into consideration. The method is used in some examples, showing how the method may be applied.
    Notes: Übersicht Blitzschläge in Freileitungen führen zu Überspannungen, die sich als Wanderwellen ausbreiten. Die Berechnung dieser Überspannungen wird durch die systematische Anwendung von Keilwellen vereinfacht. Zur raschen Berechnung der Überspannungen in einfachen Anlagen werden Formeln hergeleitet, mit denen auch die Schutzwirkung von Überspannungsableitern berechnet werden kann. Anwendungsbeispiele veranschaulichen den Rechnungsgang und geben Aufschluß über die Anwendungsmöglichkeiten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01570955
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  • 11
    Electronic Resource
    Electronic Resource
    Luftspaltfeld, induzierte Stabspannung und Schubkräfte beim Kurzstator-Linearmotor (1980)
    Springer
    Electrical engineering 62 (1980), S. 233-242 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The description of the magnetic field in the air-gap of a short-primary linear induction motor, and the subsequent calculation of the thrust developed and the voltages induced in the stator bars can be made by using balancing waves. These balancing waves are generated at any point where the field wave that would exist in a machine of infinite length is disturbed. In the linear motor these disturbances occur at the ends of the stator iron and at discontinuities in the distribution of the stator winding, which exist in machines having stepped windings. From the points where they are generated, free balancing waves travel in two directions and determine the performance of these machines to a lange extent. The voltage they induce in a stator bar can be determined from the core flux and mapped on a phasor diagram. The resulting voltage phasor follows a logarithmic spiral. The resulting voltages induced in the three phase windings form a strongly asymmetrical system which can be split-up into positivenegative- und zerosequence components depending on the slip. The tangential forces may be calculated as the product of the magnetic flux density in the air-gap and the linear current density in either stator or the reaction rail. As the “magnetic tail” outside the machine also gives rise to forces in the direction of motion, both methods yield quite different force distributions, though for the resulting force the same value is found.
    Notes: Übersicht Die Beschreibung des Feldverhaltens wie die daraus resultierende Bestimmung der erzeugten Schubkräfte und der induzierten Stabspannungen ist recht einfach mit Hilfe der Ausgleichswellen möglich. Diese Ausgleichswellen entstehen an den örtlichen Störstellen eines Motors. Beim Linearmotor sind das die Maschinenenden und die Strombelagsänderungen der abgestuften Wicklungsteile. Von diesen Störstellen wandern die freien Ausgleichswellen nach beiden Seiten und bestimmen weitgehend das Betriebsverhalten dieser Motoren. Die induzierte Stabspannung läßt sich aus dem Jochfluß ableiten und als Ausgleichswelle phasengerecht darstellen. Mit der stationären Lösung zusammen beschreibt diese eine logarithmische Spirale. Auf die drei Phasen aufgeteilt ergibt sich eine starke Unsymmetrie in den induzierten Spannungen, die zu schlupfabhängigen Mit-, Gegen- und Nullspannungssystemen führt. Die Schubkräfte werden sowohl durch das Produkt der Luftspaltinduktion mit dem Ständerstrombelag wie mit dem Schienenstrombelag beschrieben. Beide Ergebnisse stimmen nur in der Summe überein, da der magnetische Schweif hinter dem Motor auch noch Schubkräfte liefert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01570953
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  • 12
    Electronic Resource
    Electronic Resource
    Dynamische Netzberechnunǵen mit Raumzeiǵerkomponenten (1980)
    Springer
    Electrical engineering 62 (1980), S. 275-281 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents For analyses of dynamic effects in large three-phase-a.c. power systems the advantageous use of space-phasor components is put forward. These components only need a minimum of network-nodes and-branches, because they are more decoupled than any other kind of modal components within DIN 13321. The integration step size can reach a maximum, since all quantities in steady-state balanced condition are not dependent on time. The complex coefficients for the step-by-step integration in absolute stability (Trapeziummethod) are described as well as the coupling conditions of the components at points of unbalance or nonlinearity.
    Notes: Übersicht Zur Berechnung dynamischer Vorgänge in ausgedehnten Drehstromnetzen wird die Verwendung von Raumzeigerkomponenten vorgeschlagen. Sie kommen mit der minimalen Menge an Netzknoten und-zweigen aus, da sie von allen Modalkomponenten nach DIN 13321 am stärksten entkoppelt sind. Die zulässige Integrationsschrittweite ist maximal, da alle Größen im stationären symmetrischen Zustand zeitunabhängig sind. Die komplexen Schrittkoeffizienten zur absolut stabilen Integration nach der Trapezregel sowie die Kopplung der Komponenten an Unsymmetriestellen und Nichtlinearitäten werden angegeben.
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    URL: http://dx.doi.org/10.1007/BF01570957
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  • 13
    Electronic Resource
    Electronic Resource
    Rotierender Zylinderring im Felde ausgeprägter Pole (1980)
    Springer
    Electrical engineering 62 (1980), S. 295-300 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents A conducting cylindrical ring is fixed on to high-permeable cylinder which rotates with uniform angular velocity in the field of two salient poles with dc-excitation. Compared with the skindepth of the ring-material at the rotation frequency under consideration, the thickness of the ring is fairly small. An analytical method is developed to determine the induced current distribution and the losses in the ring as well as the required driving moment. The method given leads to a characteristic dependence of these quantities on an universal parameter unifying the angular velocity, the dimensions and the material properties of the ring. Under simplifying assumptions, expressions are given for the tilting moment and for the initial growth of the moment-speed dependence.
    Notes: Übersicht Ein leitender Zylinderring ist auf einem hochpermeablen Zylinder angebracht, der mit konstanter Geschwindigkeit im gleichstromerregten Feld ausgeprägter Pole rotiert. Die Wandstärke des Zylinderringes ist klein gegenüber der Eindringtiefe, die dem Werkstoff des Ringes bei den interessierenden Drehzahlen zugeordnet ist. Angegeben wird ein analytisches Verfahren zur Bestimmung der im Ring induzierten Stromverteilung, der in ihm entstehenden Verluste sowie des benötigten Antriebsmomentes. Dabei wird eine charakteristische Abhängigkeit von einem Universalparameter gefunden, in dem die Materialeigenschaften, die Abmessungen und die Winkelgeschwindigkeit des Ringes vereinigt sind. Unter vereinfachenden Voraussetzungen werden Beziehungen für das Kippmoment, die Kippdrehzahl und den anfänglichen linearen Momentenanstieg angegeben.
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    URL: http://dx.doi.org/10.1007/BF01570959
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  • 14
    Electronic Resource
    Electronic Resource
    Tragkraftschwankungen bei Magnetschwebefahrzeugen mit integriertem, synchronem Linearantrieb und ihre sicherheitstechnische Bedeutung (1980)
    Springer
    Electrical engineering 62 (1980), S. 301-308 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents In this paper the influence of the motor current on the magnetic force is investigated by an analytical method. With the integrated synchronous linear motor the reactions of the current sheet on the excitation field are depending on the pole angle and the amplitude of the current sheet. For an undisturbed operation — current sheet and induction wave in phase — the influence of the motor current on the magnetic force can be neglected. In case of a disturbed performance, i.e. when the pole angle is changing periodically, fluctuations of the magnctic force will be found. This effect has to be compensated by a reserve magnetic force in the levitation control. With the technical data for the new magnetic levitation pilot plants (International Traffic Fair 1979 at Hamburg and Transrapid — Pilot Plant Emsland) the stated relations are evaluated. Approximated relations for the levitation force are derived. For comparison, a finite-difference computer programme from the “Institut für elektrische Maschinen, Antriebe und Bahnen, Technische Universität Braunschweig” is applied. The approximated relations developed in this paper are verified — with a sufficient precision — by the numerical calculations.
    Notes: Übersicht In der vorliegenden Abhandlung wird mit Hilfe eines analytischen Verfahrens der Einfluß des Motorstromes auf die Tragkraft untersucht. Rückwirkungen des Statorstrombelages auf das Erregerfeld sind beim synchronen Langstatorantrieb über den Pollagewinkel und die Strombelagsamplitude gegeben. Im ungestörten Betrieb — Strombelagsund Induktionswelle in Phase — ist der Einfluß des Statorstromes auf die Magnettragkraft infolge der Ankernutung zu vernachlässigen. Im gestörten Betrieb, also beim durchlaufenden Pollagewinkel, treten Tragkraftschwankungen auf, die durch eine Stellkraftreserve in der Tragkraftregelung kompensiert werden müssen. Mit den technischen Daten der neuen Magnetschwebe-Versuchsanlagen (zur Internationalen Verkehrs-Ausstellung 1979 in Hamburg — IVA-Bahn —, Transrapid Versuchsanlage Emsland — TVE —) werden die aufgestellten Beziehungen ausgewertet. Die Kontrolle der praxisnahen Betrachtung und der daraus entwickelten Näherungsbeziehung für die Tragkraft erfolgt mit einem Feldberechnungsprogramm des Institutes für elektrische Maschinen. Antriebe und Bahnen der TU-Braunschweig. Die numerischen Berechnungen bestätigen das im Rahmen der vorliegenden Abhandlung entwickelte Näherungsverfahren mit einer für die Praxis ausreichenden Genauigkeit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01570960
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  • 15
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    Electronic Resource
    Dreidimensionale numerische Berechnung magnetischer Felder mit Hilfe eines Summationsverfahrens (1980)
    Springer
    Electrical engineering 62 (1980), S. 327-333 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents By a method of summation it is possible to calculate the magnetic fields in steady state numerical and tridimensional under presence of ferromagnetic material. This method is based on an integral equation for the magnetization and requires only the subdivision of the regions which consist of ferromagnetic material. The method is shown and the difficulties are described. A comparison between calculation and measurement shows a very good correlation for a simple experimental arrangement.
    Notes: Übersicht Mit dem Summationsverfahren gelingt es stationäre magnetische Felder bei Anwesenheit ferromagnetischer Materialien dreidimensional numerisch zu berechnen. Es geht von einer Integralgleichung für die Magnetisierung aus und diskretisiert nur die Bereiche, in denen sich magnetisierbare Werkstoffe befinden. Nach der Ableitung des Summationsverfahrens werden die Schwierigkeiten bei der Programmierung beschrieben. Ein Vergleich zwischen Rechnung und Messung ergibt bei einer einfachen Versuchsanordnung sehr gute Übereinstimmung.
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    URL: http://dx.doi.org/10.1007/BF01579002
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  • 16
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    Electronic Resource
    Leitende Zylinder im Felde senkrecht zu den Stirnseiten verlaufender erregender Leiter (1980)
    Springer
    Electrical engineering 62 (1980), S. 335-342 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The cartesian configuration of this problem contains a series of conducting rectangular cylinders brought into the air-gap formed by two high permeable non-conducting half planes. On both the inner surfaces of the halfplanes, currents perpendicular to the axes of the cylinders are flowing, thus exciting this cartesian configuration. In the case of the configuration containing circular cylinders, a series of circular cylinders of finite length is placed in a cylindrical hole surrounded by a high permeable material of no conductivity. On the periphery of this material, axial currents are flowing, thus exciting the cylindrical configuration. In both cases, the analytical equations of the induced eddycurrentlines on the cylinder surfaces are determined. The solution of the above three-dimensional problem leads to a system of linear equations for the coefficients in the series assumed for the potentials in the different regions of the configurations.
    Notes: Übersicht Bei der kartesischen Anordnung wird eine Folge leitender Rechteckzylinder im Luftspalt zwischen zwei nicht leitenden hochpermeablen Halbräumen betrachtet, auf deren Innenwänden ein zu den Zylinderachsen senkrecht verlaufender erregender Strombelag angebracht ist. Bei der zylindrischen Anordnung liegt eine Folge leitender Kreiszylinder endlicher Höhe in einer zylindrischen Bohrung vor, die vom nicht leitenden hochpermeablen Material ungeben ist, wobei auf der Peripherie ein axial gerichteter erregender Strombelag angebracht ist. Für beide Fälle wird die Gleichung der Stromlinien des auf den Zylinderoberflächen induzierten Wirbelstrombelages bestimmt. Die Lösung des vorliegenden dreidimensionalen Randwertproblemes führt auf ein lineares Gleichungssystem für die Koeffizienten der Potentialansätze, die das magnetische Feld in den Teilbereichen der betrachteten Anordnung beschreiben.
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    Ein Beitrag zur Identifikation und Approximation von Systemen mit Hilfe linearer diskreter mathematischer Modelle (1980)
    Springer
    Electrical engineering 62 (1980), S. 1-4 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents During the last years the problem of identification and approximation has been discussed in a lot of publications in the field of control and communication theory. In this paper a discrete time mathematical model with a minimal number of parameters is proposed. This canonical form permits an effective computer aided solution of these problems and is very efficient for the controller design.
    Notes: Übersicht Das Problem der Identifikation und Approximation eines dynamischen Systems durch ein lineares diskretes mathematisches Modell war in der Regelungs- und Nachrichtentechnik Gegenstand vieler Untersuchungen. In der vorliegenden Arbeit wird ein Modell vorgeschlagen, das eine wirkungsvolle rechnergestützte Ermittlung erlaubt und außerdem vom numerischen Standpunkt aus eine effektive Lösung des Syntheseproblems ermöglicht.
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    Impedances of rotor-conductors with circular cross-section of a double-cage motor (1980)
    Springer
    Electrical engineering 62 (1980), S. 13-18 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Es werden die Impedanzen des Arbeits- und Anlaufkäfigs eines Doppelkäfigmotors bei kreisförmigem Leiterquerschnitt unter Benutzung der Bubnow-Galerkin-Mothode berechnet. Die Impedanzwerte des Anlaufkäfigs werden in einer Tabelle angegeben.
    Notes: Contents Impedances of cylindrical conductors of the working and starting cages of a double-cage motor are calculated by using the Bubnow-Galerkin method. Tables of values of the impedance of a conductor of the starting cage are given.
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    Ein Beitrag zur Berechnung der Stromverdrängung in einem Bandleiter (1980)
    Springer
    Electrical engineering 62 (1980), S. 51-55 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents In the paper eddy-current distribution in a strip line is analysed by means of the Fredholm integral equation method. The results obtained are compared with the results achieved elsewhere by means of the other methods.
    Notes: Übersicht In der vorliegenden Arbeit wird die Stromverteilung in einem Bandleiter mit Hilfe der Fredholmschen Integralgleichung analysiert. Es wird der Vergleich zwischen den numerisch ausgewerteten und den in der Literatur mit Hilfe von anderen Verfahren berechneten Ergebnisse durchgeführt.
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    URL: http://dx.doi.org/10.1007/BF01578117
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    Möglichkeiten zur Darstellung eines Fixpunktes der Spannungsskale im Hochspannungsbereich (1980)
    Springer
    Electrical engineering 62 (1980), S. 37-42 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents A procedure is proposed for the definition of fixed points of the voltage scale in the high-voltage range. The procedure is based on an elementary nuclear process, namely the pair production which has a distinct energy threshold. From this value, fixed points of the voltage scale are to be deduced by means of a particle accelerator. On the basis of present knowledge, the realizability in the case of d.c. voltage and for electrons as charge carriers is investigated. The relative total uncertainty of the fixed point at 1022 kV is estimated to be 〈10−4. Thus a possibility is presented of fixing the voltage scale in the range of very high voltages and calibrating high-voltage measuring devices.
    Notes: Übersicht Für die Darstellung von Fixpunkten der Spannungsskale im Hochspannungsbereich wird ein Verfahrcn vorgeschlagen und auf seine Realisierungsmöglichkeit hin theoretisch untersucht. Das Verfahren baut auf einen elementar berechenbaren kernphysikalischen Prozeß, dem Paarerzeugungsprozeß, auf, der einen ausgeprägten Schwellwert der Anregungsenergie bei 1022 keV besitzt. Aus diesem Energiewert sollen mittels eines Teilchenbeschleunigers Fixpunkte der Spannungsskale abgeleitet werden. Auf der Basis des heute vorliegenden Wissens wird die Realisierungsmöglichkeit für den Fall der Gleichspannung und für Elektronen als Ladungsträger kritisch untersucht und positiv beurteilt. Die relative Gesamtunsicherheit für die Darstellung des Fixpunktes bei 1022 kV wird auf 〈1·10−4 abgeschätzt. Damit eröffnet sich eine Möglichkeit, die Spannungsskale durch einen Fixpunkt im Bereich sehr hoher Spannungen abzusichern und Hochspannungsmeßkreise mit seiner Hilfe zu kalibrieren.
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    Praktische Berechnung der Gegeninduktivität zweier kreisförmigen Leiterschleifen in allgemeiner Lage (1980)
    Springer
    Electrical engineering 62 (1980), S. 351-357 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents As a response to numerous inquiries from the industrial sector, a simple integral, which can be calculated without any difficulty using the hints provided in this paper, for the calculation of the mutual inductance between two arbitrarily located loops, is given here. — This integral is calculated and checked in the cases of small loops and coaxial loops. The mutual inductance of the corresponding plane configuration is calculated so as to enable comparison. The various results are found to tally very well with each other.
    Notes: Übersicht In Beantwortung zahlreicher Anfragen aus der Praxis nach der Berechnung der Gegeninduktivität zweier kreisförmiger Leiterschleifen in allgemeiner Lage wird ein Einfachintegral für die gesuchte Gegeninduktivität angegeben, das unter Berücksichtigung aufgeführter Hinweise ohne Schwierigkeiten ausgewertet werden kann. Das aufgestellte Integral wird für den Fall kleiner Leiterschleifen und für koaxiale Schleifenanordnungen kontrolliert und ausgewertet. Ein Vergleich mit der Gegeninduktivität des entsprechenden Querschnittes aus einer ebenen Leiteranordnung wird vorgenommen.
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    Allgemeine Theorie des umrichtergespeisten Käfigläufermotors mit beliebiger Strangzahl der Ständerwicklung unter Berücksichtigung der Oberfelder (1980)
    Springer
    Electrical engineering 62 (1980), S. 91-101 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The general set of equations of the squirrel-cage motor with m stator phase windings has been transformed into its symmetrical components. The reduced equations allow a distinctive calculation of the machine performance. A transformation of the supply currents or voltages generated by rectifier-inverters shows which current harmonics act together with the space harmonics in the case of different phase numbers. An example shows the effect of the phase number on the oscillating torque for the case of trapezoidal current excitation.
    Notes: Übersicht Das allgemeine Gleichungssystem des Käfigläufermotors mitm Ständerwicklungssträngen wird der Transformation in symmetrische Komponenten unterzogen. Die derart vereinfachten Gleichungen gestatten eine übersichtliche Berechnung des Betriebsverhaltens. Eine Transformation der speisenden Ströme bzw. Spannungen aus Zwischenkreisumrichtern läßt erkennen, welche Oberschwingungen mit den eiazelnen räumlichen Harmonischen des Luftspaltfeldes bei den verschiedenen Strangzahlen zusammenwirken. Anhand eines Beispiels wird der Einfluß der Strangzahl auf die Pendelmomente bei trapezförmigem Zeitverlauf der Ständerströme gezeigt.
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    Transient magnetic fields in the superconducting alternator (1980)
    Springer
    Electrical engineering 62 (1980), S. 131-140 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Zur Berechnung transienter Magnetfelder bei einem 1,3 GVA Generator mit supraleitender Erregerwicklung wird die Fourier-Transformation verwendet. Die erforderlichen Frequenzgänge werden an einem maßstabgerechten Modell gemessen und daran die räumliche Änderung des transienten Feldes dargestellt. Die Untersuchung zeigt die Punkte stärkster Flußänderung auf der Erregerwicklung.
    Notes: Contents The Fourier Transform method is used to compute transient magnetic fields in a 1.3 GVA superconducting alternator. The necessary frequency-response functions are measured in a scale-model and are used to show the spatial variation of the transient field. The study brings out the points on the field winding at which magnetic transients will be most severe.
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    Induzierte Wirbelstromverteilung in kreiszylindrischen und lanǵǵestreckten Proben endlicher Höhe (1980)
    Springer
    Electrical engineering 62 (1980), S. 243-254 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents For purposes of material testing, a test-body in the form of a circular cylinder is placed concentrically in the airgap of a closedring magnet out of iron. A solenoid of rectangular cross-section consisting of thin windings and carrying alternating current is used to excite this configuration. Using the lucid matrix method, through inversion of a linear system of equations, the induced eddy currents in the test-body the equivalent current function for it and the loss of energy in it, are calculated. The modified Bessed functions encountered in the above analysis, generally of complex argument, are discussed in the mathematical appendix and their graphical representation for different parameter values is also given therein. The case of an elongated symmetrical test configuration, with the currents flowing in the coil having opposite directions is also studied using the same approach. The general results obtained are used to analyse the plane configuration with a form of surface current excitation and the calculated values are compared with the closed form solution obtained using conformal transformation for the case of very small skindepth.
    Notes: Übersicht Im Luftspalt eines eisengeschlossenen Ringmagneten befindet sich zum Zwecke der Materialprüfung konzentrisch ein kreiszylindrischer, leitender Probekörper. Die Erregung der beschriebenen Anordnung erfolgt durch eine aus dünnen Windungen bestehende, wechselstromdurchflossene Spule rechteckförmigen Querschnittes. Die im Probekörper induzierte Wirbelstromverteilung, die Ersatzstromfunktion sowie die in ihm umgesetzten Verluste werden mit Hilfe der übersichtlichen Matrizendarstellung durch Inversion eines linearen Gleichungssystems berechnet. Die dabei auftretenden modifizierten Besselschen Funktionen allgemein komplexer Argumente werden im mathematischen Anhang erläutert, wobei deren Verlauf für verschiedene Parameterwerte graphisch dargestellt wird. Weiterhin wird auf den Fall einer langgestreckten, symmetrischen Versuchsanordnung eingegangen, deren Spulenseiten von entgegengesetzt gerichteten Strömen durchflossen werden. Abschließend werden die allgemeinen Ergebnisse am Beispiel der ebenen Anordnung mit strombelagförmiger Erregung ausgewertet und für den numerisch kritischen Fall kleiner Eindringtiefe mit einer, durch konforme Abbildung gefundenen, geschlossenen Lösung verglichen.
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    Analytische Bestimmung des Nutungseinflusses auf die Feldverteilung und die Wirbelstromverluste in dauermagneterregten Synchronmaschinen (1980)
    Springer
    Electrical engineering 62 (1980), S. 283-293 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The paper presents an analytical method for calculating the field distribution in the airgap and magnet regions of permanent-magnet synchronous machines. The analysis is based on a symplified model which considers the slotting structure of the stator. The resulting distribution of the no load flux density is utilized to find an expression for the eddy current losses in the magnets due to the tooth harmonic fields. Comparison with test results obtained from experimental model and with numerical field calculation shows close agreement. The influence of some design parameters on the eddy current losses in the magnets is investigated.
    Notes: Übersicht Ausgehend von einem vereinfachten Modell wird ein analytisches Rechenverfahren entwickelt, das den Nutungseinfluß auf die Feldverteilung im Luftspalt und im Magnetbereich einer mit Permanentmagneten erregten Synchronmaschine erfaßt. Das Verfahren liefert die Leerlaufinduktionsverteilung im Luftspalt und im Magnetbereich sowie die Wirbelstromverluste in den Magneten. Die Genauigkeit des Verfahrens wird durch einen Vergleich mit Meßergebnissen und numerischen Feldberechnungen überprüft. Die Abhängigkeit der Wirbelstromverluste in den Magneten von verschiedenen Entwurfsparametern wird angegeben und diskutiert.
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    Bemessunǵsreǵeln für Transformatoren (1980)
    Springer
    Electrical engineering 62 (1980), S. 309-315 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents In the first part, on the base of an idealized type, the ring-transformer, the essential principles already could be mathematically formulated. In the second part, they will be adapted to the usual transformer-types.
    Notes: Übersicht Im ersten Teil konnten anhand einer idealisierten Bauform, des Ringtransformators, bereits die wesentlichen Gesetzmäßigkeiten mathematisch formuliert werden. Im zweiten Teil werden sie an die gebräuchlichen Transformatortypen angepaßt.
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    Thin-wire antenna in the presence of a perfectly conducting sphere (1980)
    Springer
    Electrical engineering 62 (1980), S. 317-319 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht In diesem Artikel wird eine neue numerische Methode für die Bestimmung der Stromverteilung und des Eingangsscheinwiderstandes von einer dünnen, radianlen Drahtantenne in Anwesenheit einer vollkommen leitenden Kugel angegeben. Darin werden zwei verschiedene Antennen behandelt: die radikale Dipol-Antenne und die Monopolantenne, die im Fußpunkt gegen der Kugel erregt ist. Die aufgestellten (Halléns Art) Integralgleichungen werden numerisch mit der Stützstellenmethode gelöst. Die Stromverteilungsfunktion längs der Antenne wird durch ein Polynom approximiert. Die numerischen Ergebnisse stimmen mit den Resultaten der anderen Autoren überein.
    Notes: Contents In this paper a new numerical method for determining the current distribution and input impedance of thinwire radial antennas in the presence of a perfectly conducting sphere is given. Two particular cases, a radial dipole antenna and a monopole antenna above the sphere are analysed. The method is based on Green's function for the Hertz dipole above the sphere and on the integral equations of Hallén type. The integral equations are numerically solved by the point-matching method combined with the polynomial approximation of the current distribution on the antenna conductors. The obtained results are compared with the corresponding results of other authors.
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    Ein im Zeitbereich arbeitendes automatisches Entwurfsverfahren für elektrische Filter (1980)
    Springer
    Electrical engineering 62 (1980), S. 321-326 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents Design of smoothing filters for power electronic applications can be realized better in time domain than in frequency domain. Using Kirchhoff's laws differential equations can be derived to describe the network in state space; the transition matrix is used for the solution. For arbitrary periodic input time functions initial conditions of all state variables are calculated which lead to the stationary solution. From the simulation of one period a criterion is determined. The minimization of this criterion leads to the optimal choice of design parameters. The stationary solution is calculated and discussed for specific chopper circuits. For other examples the critical (minimal) inductivity is determined.
    Notes: Übersicht Der Entwurf von Glättungsfiltern in der Leistungselektronik erfolgt besser im Zeitbereich als im Frequenzbereich. Aus den bekannten Kirchhoffschen Gesetzen erhält man die Differentialgleichungen zur Beschreibung des Netzwerkes im Zustandsraum. Für die Lösung wird die Transitionsmatrix verwendet. Für periodische Eingangszeitfunktionen beliebiger Form werden die Anfangsbedingungen berechnet, die auf eine stationäre Lösung, d. h. auf einen solchen Periode wird ein Kriterium berechnet, mit dessen Hilfe unter Verwendung bekannter Optimierungsverfahren die Schaltung dimensioniert wird. Die stationäre Lösung wird für das Beispiel eines Sperrwandlers berechnet und diskutiert; für andere Filterkonfiguration wird jeweils die kritische (minimale) Induktivität berechnet.
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    A quasi analytical procedure for determining the optimum commutation angles of PWM converters (1980)
    Springer
    Electrical engineering 62 (1980), S. 343-350 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Man beschreibt ein meist analytisches Verfahren für die Berechnung der optimalen Steuerwinkel für pulsbreiten-modulierte Frequenzumrichter. Durch dieses Verfahren wird es möglich, den Zeitverlauf der bedeutendsten elektrischen und nichtelektrischen Größen des Systems zu optimieren. Das Rechnungsverfahren beruht auf meistens erfüllten Annahmen; auf Grund seiner einfachen und schnellen Durchführung braucht man in den meisten Fällen nur Minicomputer zum Zweck.
    Notes: Contents A method for calculating the optimum commutation times for PWM converters is proposed. The method is mainly analytical and leads to a simple, fast calculation procedure. The time behaviour of any variable, electrical or non electrical, which is considered to be the most characteristic of the behaviour of the system, can be optimized. The validity of the analytical approach is subject to some hypotheses which are often verified in practice. The computation power required by the method is so limited that, in the majority of cases, a minicomputer can be used.
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    Elektromechanische Schwingungen, die mit nichtlinearen aktiven Netzwerken selbsterregt werden (1980)
    Springer
    Electrical engineering 62 (1980), S. 5-12 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents Electromechanical convertion system contains three parts: the electrical system, the convertional device and the mechanical system. In the paper it is analyzed an electromechanical convertion realyzed by an electrical system, described by a first-order nonlinear differential equation, and a mechanical system described by a second-order linear differential equation. The convertional device analized in the paper, consists in the magnetoelectric measuring aparatus, that can perform torsional oscillations. it results from the analysis that if the working point of the electrical system is unstable the mechanical system performs sustained oscillations described by nonlinear differential equation of the type Rayleigh.
    Notes: Übersicht Die elektromechanische Konversionssysteme enthalten drei Teile: das elektrische System, die Konversionsanlage und das mechanische System. In der Arbeit wird die elektromechanische Konversion, die durch einer nichtlinearen Differentialgleichung erster Ordnung beschriebenes elektrisches System und ein durch einer linearer Differentialgleichung zweiter Ordnung beschriebenes mechanisches System, analysiert. Die untersuchte Konversionsanlage ist ein magnetselektrisches Messungsgerät, welches Torsionsschwingungen ausüben kann. Aus der Analyse folgt, daß neun der Arbeitspunkt des elektrischen Systems instabil ist, dann übt der mechanische System selbsterregte Schwingungen, die von einer nichtlinearen Differentialgleichung von Rayleighschem Typ beschrieben sind, aus.
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    Digital calculation of earthing systems in nonuniform soil (1980)
    Springer
    Electrical engineering 62 (1980), S. 19-24 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Es wird ein mathematisches Modell für die aus geradlinigen Elementen zusammengesetzten Erdungsanlagen in geschichtetem Erdreich entwickelt. Die vorgeschlagene Methode ermöglicht die Berechnung aller Kennlinien der Erdungsanlage bei Anwendung eines allgemeinen Verfahrens, das auf der elementaren Daten über die Konfiguration der Erdungsanlage und des Erdreiches beruht.
    Notes: Contents The mathematical model of earthing systems consisting of straight-line elements in the nonuniform soil is developed. The method presented enables the evaluation of all earthing system characteristics by applying a general algorithm, appropriate for digital computing, based upon elementary data of the earthing system and soil configuration.
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    Transienter Skineffekt in einer Hohlkugel im erregenden ebenen Feld von Leitern (1980)
    Springer
    Electrical engineering 62 (1980), S. 25-35 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents Generally, for the calculation of the distribution of the eddy current transients in a sphere, an integration has to be performed along the arbitrary contour of the exiting loop of current having an arbitrary time dependence. This paper deals with the solution of this problem for a hollow sphere placed in the planar field of excitation of a system of conductors, whereby the contour integration is avoided. Solutions derived are verified with the discrete solutions obtained in the case of sinusoidal excitation. The practically important screening effect of a thin hollow sphere on transient field produced by current impulses flowing through two conductors is also discussed. The field plottings in the hollow space of the sphere are derived out of the closed form solution and are also given for different instances of the transient excitation. The time dependence of the magnetic flux penetrating the area of a square inside the hollow sphere is analysed and is given as a function of the duration of the exciting impulse.
    Notes: Übersicht Die Berechnung der transienten Wirbelstromverteilung in einer Kugel erfordert allgemein eine Integration über die erregende Leiterschleife beliebiger Kontur, die einen Strom mit beliebiger Zeitabhängigkeit führt. In der vorliegenden Abhandlung wird die Lösung dieses Problems für eine Hohlkugel, die sich im ebenen Feld einer erregenden Leiteranordnung befindet, ohne Konturintegration angegeben und für den Fall zeitlich sinusförmiger Abhängigkeit der Feldgrößen mit der dann möglichen direkten Lösung der Differentialgleischungen überprüft. Der unter praktischen Gesichtspunkten wichtige Fall der Abschirmung transienter Felder durch eine Hohlkugel geringer Wandstärke wird für einen Stromimpuls auf einer erregenden Doppelleitung behandelt. Aus der geschlossen darstellbaren Lösung werden die Feldbilder im Kugelhohlraum zu verschiedenen Zeitpunkten der transienten Feldänderung angegeben und der Zeitverlauf des magnetischen Flusses durch eine quadratische Fläche im Innern der Kugel wird in Abhängigkeit von der Zeitdauer des erregenden Stromimpulses untersucht.
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    Vollständige Einheitsnullteiler und ihre Anwendungen in der elektrischen Netzwerktheorie (1980)
    Springer
    Electrical engineering 62 (1980), S. 57-62 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents Complete normed annihilators are applicated to the following problems: Derivation of the loop and cut set method from the node method, normal forms of rectangular arrays of ideal transformers, equivalent circuits in symmetrical components for short-circuits and disconnections in multiphase interconnected systems. The existence of complete normed annihilators is proved. Normed annihilators generate most simple relations.
    Notes: Übersicht Vollständige Einheitsnullteiler werden auf folgende Aufgaben angewandt: Herleitung der Maschen- und Schnittmengenmethode aus der Knotenmethode, Normalformen von rechteckgen idealen Übertragermatrizen, Ersatzschaltungen in symmetrischen und anderen Komponenten für Kurzschlüsse und Unterbrechungen in mehrphasigen Verbundnetzen. Hierzu wird die Existenz von vollständigen Einheitsnullteilern für singuläre Matrizen nachgewiesen. Einheitsnullteiler erzeugen besonders einfache Beziehungen.
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    Digitale Simulation von Asynchronmotorengruppen bei Netzumschaltungen (1980)
    Springer
    Electrical engineering 62 (1980), S. 81-90 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents In self-supply systems of thermal power plants sometimes a large number of induction motors has to be changed over to a reserve supply if mains interruptions occur. The digital simulation offers the possibility to calculate the dynamic performance of the drives already at the stage of planning. A mathematical model describing induction motor groups is developed and prepared for the simulation of change-over processes by digital computing.
    Notes: Übersicht In Kraftwerks-Eigenbedarfsnetzen muß bei Netzstörungen mitunter eine größere Anzahl von Asynchronmotoren auf eine Reserveeinspeisung umgeschaltet werden. Die digitale Simulation bietet die Möglichkeit, das dynamische Verhalten der Antriebe während des Umschaltvorganges schon bei der Planung genau zu berechnen. Es wird ein mathematisches Modell zur Berechnung beliebiger Motorengruppen entwickelt und für die Simulation von Netzumschaltungen mit Hilfe eines Digitalrechners aufbereitet.
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    Elektrostatik bei Anwesenheit von linearer und isotroper Quadrupolmaterie (1980)
    Springer
    Electrical engineering 62 (1980), S. 103-115 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents By means of calculus of variations the differential equation and also the boundary conditions of electrical potential are derived, both of them are describing the polarisation of quadrupole matter. Three basic electrostatic problems are explicitly calculated by these equations.
    Notes: Übersicht Es werden mit Hilfe der Variationsrechnung sowohl die Differentialgleichung als auch die Randbedingungen des elektrischen Potentials bei Polarisation von Quadrupolmaterie abgeleitet. Mit diesen Gleichungen werden drei Grundaufgaben der Elektrostatik explizit durchgerechnet.
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    URL: http://dx.doi.org/10.1007/BF01578639
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    Widerstandserhöhung eines zylindrischen Leiters infolge einer exzentrischen Querschnittseinengung endlicher Länge (1980)
    Springer
    Electrical engineering 62 (1980), S. 117-123 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents In this paper, an analytical method of determining the current distribution in cylindrical conductors with sudden and eccentric cross-sectional constriction is developed. The motivation lies in the hairline cracks due to fatique ruptures observed in practice. The problem is three-dimensional as a result of the eccentricity in the configuration and leads to a system of linear equations for the coefficients in the potential expressions. The voltage rise due to the eccentric constriction is calculated using equations mentioned above, where-by a uniform cylindrical conductor is taken as reference. The increase of resistance is then determined from the voltage rise.
    Notes: Übersicht In der vorliegenden Abhandlung wird ein analytisches Verfahren zur Bestimmung der Stromverteilung in zylindrischen Leitern entwickelt, die eine sprunghafte, exzentrisch gelegene Querschnittsverengung erfahren. Veranlassung dazu gab das Auftreten von Haarrissen bei Dauerbrüchen. Wegen der vorhandenen Exzentrizität liegt ein räumliches Randwertproblem des stationären Strömungsfeldes vor, das die Lösurg linearer Gleichungssysteme für die Koeffizienten des Potentialansatzes verlangt. Mit diesen wird die Potentialerhöhung bestimmt, die die exzentrische Querschnittsverengung gegenüber einem Zylinder konstanten Querschnitts verursacht, womit auch die gesuchte Widerstandserhöhung bekannt ist.
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    Stromverteilung in wechselstromdurchflossenen massiven Kröpfungen (1980)
    Springer
    Electrical engineering 62 (1980), S. 125-130 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The turning under consideration consists of two bars connected at right angles by a coupling of different conductivity. The skineffect boundary value problem in question is solved by setting up expressions for the magnetic field and satisfying the boundary conditions on the junction. This leads to a system of linear equations for the setupcoefficients, that is solved numerically. Using matrix notation, general expressions for the stream function are given, checked and evaluated. The ac-results are discussed by comparison with the dc-solution found by conformal mapping. It's found for cases of practical interest, that in the intermediate neighbourhood of a sharp edged turning no reasonable difference exists between the ac- und dc-distributions.
    Notes: Übersicht Die betrachtete Kröpfung besteht aus zwei Schienen, die durch ein rechtwinklig angeordnetes Verbindungsstück verschiedener Leitfähigkeit miteinander verbunden sind. Das vorliegende Problem des Skineffektes wird durch Aufstellung von Ansätzen für die magnetische Feldstärke und durch die Erfüllung der Randbedingungen an der Stoßstelle gelöst. Dies führt zu einem linearen Gleichungssystem für die Koeffizienten des Feldstärkenansatzes, das numerisch aufgelöst wird. Bei Verwendung der Matrizenschreibweise werden allgemeine. Beziehungen für die Stromfunktion aufgestellt, geprüft und ausgewertet. Die für die Speisung mit Wechselstrom gefundenen Ergebnisse werden durch einen Vergleich mit der Gleichstromverteilung diskutiert, die man mittels der konformen Abbildung erhält. Dabei zeigt sich, daß für praktisch interessierende Ausführungen in der unmittelbaren Nachbatschaft einer scharfen Umlenkung kein merklicher Unterschied zwischen der Wechselstrom- und Gleichstromverteilung besteht.
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    Study of the magnetic field in superconducting alternators (1980)
    Springer
    Electrical engineering 62 (1980), S. 141-151 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Im Rahmen der vorliegenden Abhandlung werden die radialen und tangentialen Komponenten des magnetischen Feldes innerhalb eines dreiphasigen, mit supraleitender Feldwicklung ausgeführten Turbogenerators mit rotierender Abschirmung an Hand einer ebenen Betrachtung stationär und transient berechnet. Die darin angegebenen Beziehungen gelten für beliebige Ordnung der Feldharmonischen und für beliebige Polpaarzahlen des Generators, wobei die Dicke der Rotor- und Statorwicklung endlich ist und die Wirbelstromverteilung den tatsächlichen Verhältnissen entspricht. Am Beispiel eines zweipoligen leerlaufenden Turbogenerators von ca. 1300 MVA mit zweifacher Rotorabschirmung wurde die Verteilung der magnetischen Flußdichte, deren Oberwellengehalt sowie das stationäre und transiente Verhalten der rotierenden Abschirmung untersucht.
    Notes: Contents In this paper, the radial and tangential components of the magnetic field inside a three-phase turbogenerator with superconducting field winding and with a rotating screen of any number of elements are calculated with reference to a twodimensional study and to steady state and transient running. The expressions obtained are valid for any order of the field harmonic and any number of pole-pairs of the generator, and refer to a finite thickness of the rotor and stator windings and take account of the real distribution of the eddy currents in the screen elements. As an example of the applications, with reference to a preliminary design for a two-pole turboalternator of around 1300 MVA with “double” rotor screen, the distribution of the flux density with no load and its content of harmonics are found and the steady state and transient behaviour of the rotor screen is analyzed.
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    Reverse problems for diffusion equation (1980)
    Springer
    Electrical engineering 62 (1980), S. 177-180 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Im Rahmen der vorliegenden Abhandlung werden dic Randbedingungen erster und zweiter Art von inversen Diffusionsrandwertproblemen bestimmt. Den Ausganspunkt der Überlegungen bildet die Regularisationsmethode von Tichonov zur Lösung der Volterra-Integralgleichung erster Art. Die theoretischen Ergebnisse werden am Beispiel einerRC-Ubertrangnngsstrecke numerisch ausgewertet.
    Notes: Contents The paper deals with the analysis of the reverse problems for diffusion equation depending on determination of the boundary conditions of the first and second kind. The idea of proposed method consists on solving the Volterra integral equations of the first kind by means of Tichonov's regularisation method. Theoretical consideration were illustrated by numerical calculations of reverse problems for the uniformR, C transmission line.
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    Bestimmung von Wirbelströmen im Vakuumgefäß einer Apparatur zur Erforschung der kontrollierten Kernfusion (1980)
    Springer
    Electrical engineering 62 (1980), S. 181-186 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The induction process induced in a toroidal vacuum vessel by sudden disruption of the plasma current is analyzed in the case of the ASDEX tokamak experiment by an approximation method. For this purpose the rotation symmetric vessel is regarded as parallel connected, circular, lossy conductors magnetically coupled with one another and with the plasma. The transient currents and voltages occurring in the network are numerically calculated. The current distribution in the vessel walls can then be given directly from these currents. In addition, the currents induced in the vessel walls are measured in a 1:10 model taking the necessary scaling factors into account. The experimental and calculated results are compared.
    Notes: Übersicht Der durch einen plötzlichen Abriß des Plasmastromes in einem ringförmigen Vakuumgefäß hervorgerufene Induktionsvorgang wird am Beispiel des Tokamak-Experimentes ASDEX mit Hilfe einer Approximations-Methode ana-lysiert. Dazu wird das rotationssymmetrische Gefäß als Parallelschaltung kreisfömiger, verlustbehafteter Leiter aufgefaßt, die miteinander und mit dem Plasma magnetisch gekoppelt sind. Die in diesem Netzwerk auftretenden transienten Ströme und Spannungen werden numerisch berechnet. Aus den Strömen kann unmittelbar die Stromverteilung in den Gefäßwänden angegeben werden. Außerdem wurden die Ströme in den Gefäßwänden gemessen. Hierzu diente ein Modell im Maßstab 1:10. Auf die Skalierungsfaktoren wird eingegangen. Die Ergebnisse aus Messung und Rechnung werden gegenübergestellt
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    Application of boundary solution procedure in thermal field analysis (1980)
    Springer
    Electrical engineering 62 (1980), S. 195-200 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht In diesem Aufsatz wird eine neue Methode der Feldanalyse angegeben, um die Temperaturverteilung infolge eines im Erdboden verlegen Starkstromkabels zu bestimmen. Diese Methode erlaubt die Bestimmung der Temperaturverteilung im gesamten, unendlich ausgedehnten Gebiet, obwohl die finiten Elemente nur in der unmittelbaren Umgebung des Kabels angewendet werden. Im Programm werden die isoparametrischen Elemente gebraucht, in denen die Approximation der zweiten Ordnung angewandt wird. Die Ergebnisse sind genauer als mit der Benutzung der konventionellen Methode der finiten Elemenente. Mit dem Algorithmus, der hier dargestellt wird, kann man auch die Temperaturfelder der Heizelemente modellieren.
    Notes: Contents A new method for the thermal field analysis for the determination of the temperature distribution around a heavy-current underground cable, is given in this paper. Using finite elements in the immediate neighbourhood of the cable, it is possible to determine the temperature distribution in the whole infinite region. The method of isoparametric elements with second order approximation is used for the numerical computations. The results obtained are more accurate than those obtained using conventional finite element methods (FEM). The algorithm developed here can be easily adopted for the analysis of thermal field caused by underground thermal sources.
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    Die Stabilität erzwungener Schwingungen in Stromkreisen mit nichtlinearer Induktivität und Hysteresis-Schleife (1980)
    Springer
    Electrical engineering 62 (1980), S. 201-206 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The mathematical conditions to be satistied for the use of the asymptotic methods in the analysis of nonlinear R.L.C. circuits with hysteresis are given. With the help of this, the stability of the forced oscillations of the magnetic flux is analysed. The nonlinear flux-current characteristics is represented by an odd polynomial of the fifth degree, with an additional term which accounts for the double-hysteresis behaviour. Also the cases are discussed in which the hysteresis affects and does not affect the resonance. The calculations are performed using the first-order perturbation-theory.
    Notes: Übersicht Die mathematischen Vorbedingungen zur verwendung asympfotischer Methoden bei der Analyse von nichtlinearen R-L-C-Stromkreisen mit Hysteresis-Schleife werden erläutert. Somit wird die Stabilität erzwungener Schwingungen des magnetischen Flusses analysiert. Die nichtlineare Strom-Fluß-Charakteristik besitzt die Gestalt eines ungeraden Polynoms fünften Grades, mit einem Zusatzglied, das die doppelte Hysterese hervorruft. Es werden die Fällc diskutiert, worin der Hysterese-Beitrag auf die Resonanzkurven einwirkt bzw. nicht einwirkt. Die Berechnungen werden in der Störungsrechnung erster Ordnung durchgeführt.
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    Reflexion und Brechung Hertzscher Wellen an bewegten Schichten (1980)
    Springer
    Electrical engineering 62 (1980), S. 207-218 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The following investigation deals with the perturbation of Hertzian waves as used in Radar by the occurence of moving layers containing material particles. A simplified model of such a layer is given, and the equations of the electromagnetic field are integrated both inside and outside this layer, beeing connected by the principles of relativity. Crossing the layer the originally emitted wave will be weakened and displaced. Additionally, an echo wave is created whose frequency and angle of reflection depend explicitely upon the velocity of the moving layer. Both the Doppler-Effect and the aberration of the reflected wave are computed. Furthermore it is show that by some critical values of the frequencies of the incident wave and its direction the moving layer may be totally transparent or totally reflecting. *** DIRECT SUPPORT *** A1118151 00002
    Notes: Übersicht Der Verlauf Hertzscher Wellen der Radartechnik wird durch wandernde Schichten materieller Fremdkörper gestört. Anhand eines vereinfachten Modelles werden die Feldgleichungen in und außerhalb der Störschicht unter der Annahme einfach periodischer Wellen integriert und relativistisch miteinander verknüpft. Die ursprünglich emittierte Welle wird bei der Passage der Störschicht geschwächt und seitlich verschoben. Überdies entsteht eine parasitäre Echowelle, deren Frequenz und Rückstrahlwinkel von der Bewegung der Störschicht explizit abhängen. Sowohl der Echo-Dopplereffekt wie die Echo-Aberration werden angegeben. Es werden Formel für die Relfexionsfähigkeit der Störschicht und deren Durchlaßvermögen entwickelt, welche ein optisch singuläres Verhalten der Störschicht bei gewissen Daten des Suchstrahles erwarten lassen.
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    Analytische Bestimmunǵ der Hauptreaktanzen und des Drehmomentes eines Reluktanzmotors (1980)
    Springer
    Electrical engineering 62 (1980), S. 265-273 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents In this paper, by means of the field theory an analytical method is derived to calculated the main reactances and the torque of a reluctance motor from the dimensions of the machine. At first, a motor without pole shoes is considered and then the normal salient pole type. In the field theoretical analysis, the matrix method is used to set up a system of linear equations for the coefficients describing the potential in the space under consideration. The equations mentioned above are evaluated, giving the dependence of the desired quantities as a function of the machine dimensions; results are discussed and checked.
    Notes: Übersicht In der vorliegenden Abhandlung wird ein feldtheoretisches Rechenverfahren angegeben, das die Berechnung der Hauptreaktanzen und des Drehmomentes eines vierpoligen Reluktanzmotors aus den Maschinenabmessungen ermöglicht. Dabei wird zunächst die Maschine ohne Polschuhe und dann die Ausführung mit Polschuhen behandelt. Die feldtheoretische Behandlung erfolgt in Matrizendarstellung und führt auf lineare Gleichungssysteme für die Konstanten der aufgestellten Potentialansätze. Die Auswertung liefert die Abhängigkeit der gesuchten Kenngrößen von den Maschinenabmessungen; sie wird diskutiert und einer Kontrolle unterzogen.
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    Der Einfluß der Energiespeicher im Zwischenkreisumrichter eines Asynchronmaschinenantriebs auf die Oberschwingungen (1980)
    Springer
    Electrical engineering 62 (1980), S. 359-367 
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    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents In this paper two types of induction machine drives are discussed, which use converters with an intermediate dc-link. The values of the smoothing reactances in a CSI-drive and in a VSI-drive affect the performance of the drive. The influence of the dc-link reactances on the relative harmonic content of theac-line current, the stator variables of the machine and the torque is computed by a digital simulation program.
    Notes: Übersicht Es werden zwei Antriebe mit Asynchronmaschinen untersucht, ein Antrieb mit einem Stromzwischenkreisumrichter und einer mit einem Spannungszwischenkreisumrichter. Mit Hilfe eines digitalen Simulationsprogramms wird ermittelt, wie die Größe der Energiespeicher im Zwischenkreis der Umrichter das Betriebsverhalten des Antriebs und den Oberschwingungsgehalt von Strömen, Spannungen und Drehmoment beeinflußt.
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    The backscattering technique: its field of applicability in fibre diagnostics and attenuation measurements (1980)
    Springer
    Optical and quantum electronics 12 (1980), S. 17-22 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The evaluation of power decay along the fibre by means of the backscattering technique may be altered by the presence of unknown irregularities. In the present paper the effects of such imperfections are estimated; it is demonstrated that mainly local inhomogeneities and numerical aperture fluctuations influence backscattered power. Finally an efficient and simple method for the separation of the power decay contribution from the irregularity contribution is proposed.
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    Scattering characteristics of a beam mode in a dielectric-slab optical waveguide. Part II (1980)
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    Optical and quantum electronics 12 (1980), S. 23-33 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The radiated power of scattered light caused by refractive-index inhomogeneities and waveguide wall irregularities in an asymmetric slab waveguide is investigated by using the stationary phase method on the basis of a first-order perturbation theory. The correlation between both imperfections of the refractive index and the waveguide wall is taken into consideration. It is found that the correlation between both imperfections hardly affects the radiated power caused by air radiation modes while it modifies the radiated power caused by substrate radiation modes.
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    Analyse perturbative des caractéristiques de propagation des fibres optiques à gradient d'indice quasi-parabolique (1980)
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    Optical and quantum electronics 12 (1980), S. 41-49 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract A simple perturbation theory, based on the scalar wave analysis, has been used to study the propagation characteristics of radially inhomogeneous lossless fibres. The formalism has been developed with a truncated parabolic-index profile as the zero-order solution and the perturbation approach is valid for azimuthally symmetric or anti-symmetric modes near cut-off as well as far from cut-off. In addition, numerical calculations have been carried out forα-profiles and have been found to be in good agreement with more rigorous calculations reported by previous authors.
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    Intermodal dispersion measurements and interpretation in graded-index optical fibres (1980)
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    Optical and quantum electronics 12 (1980), S. 57-64 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract We describe in this paper a frequency-domain measurement configuration allowing the determination of intermodal dispersion, differential mode attenuation and mode-coupling effects in graded-index optical fibres. Attention is mainly given to intermodal dispersion which is obtained with a resolution of 5 ps km−1 and a dynamic range of 15dB. Spatial (or modal) resolution is examined from both the theoretical and experimental point of view and the high degree of resolution of the experiment is illustrated. Interpretation of the results for deducing the index profile errors and correcting the preform manufacturing process shows the usefulness of the method for improving fibre quality.
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    Distinction of the competing processes in nonlinear resonant frequency mixing in atoms (1980)
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    Optical and quantum electronics 12 (1980), S. 35-40 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract A coherent transient response technique is applied, for the first time, to distinguish between the influence of competing processes such as saturation of atomic transition and effects due to laser-induced nonlinear polarization on nonlinear resonant mixing. Experimental research is performed for the 3s–5s two-photon transition in sodium vapour. Delaying the probe picosecond pulse after the exciting one, variations of efficiency and phase-matched ratio upon incident intensity and exciting wavelength are investigated.
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    Perturbation analysis of clad parabolic-index waveguides (1980)
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    Optical and quantum electronics 12 (1980), S. 51-56 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract A first-order perturbation technique is used to obtain the eigenfunction correction due to the cladding in a square-law dielectric waveguide. Regions both near to and far from cut-off are considered separately. It is shown that far from cut-off the fractional power carried by the guide core increases over that in the homogeneous case but that near cut-off the power in the core is less than in a homogeneous guide. Thus the stability of the modal power with variation of wavelength is increased over that in a homogeneous guide.
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    Pulse dispersion in a clad lens-like medium (1980)
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    Optical and quantum electronics 12 (1980), S. 109-118 
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    ISSN: 1572-817X
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    Notes: Abstract The effects of a homogeneous cladding on the dispersion of a square-law dielectric guide are investigated using a perturbation technique. Assuming a Gaussian, band-limited input it is shown that for single mode operation the waveguide dispersion is of the order of the material dispersion. For multimode operation the effect of the cladding on the uniformly polarized modes is examined and it is shown that a significant interaction occurs only for the two modes closest to cut-off. Comparison is made between theoretical and experimental results. The perturbation technique is used to analyse the optimum index profile proposed by Okamoto and Okoshi. It is shown that this variation reduces the dispersion to below that of the infinite medium approximation.
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    The calculation of average error probability in a digital fibre optical communication system (1980)
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    Optical and quantum electronics 12 (1980), S. 131-141 
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    Notes: Abstract This paper deals with the problem of determining the average error probability in a digital fibre optical communication system, in the presence of message dependent inhomogeneous non-stationary shot noise, additive Gaussian noise and intersymbol interference. A zero-forcing equalization receiver filter is considered. Three techniques for error rate evaluation are compared. The Chernoff bound and the Gram-Charlier series expansion methods are compared to the characteristic function technique. The latter predicts a higher receiver sensitivity.
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    A mobile computerized laser radar system for observing rapidly varying meteorological phenomena (1980)
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    Optical and quantum electronics 12 (1980), S. 159-167 
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    Notes: Abstract A high repetition, mobile laser radar system with a computerized real-time data acquisition and display system is described. Signal-to-noise levels of the system are compared with theoretical values, and it is found that they are affected by the shot noise in the system. An example of a stack plume observation is also presented to show the performance of the system.
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    Two-photon resonant fifth harmonic generation in sodium vapour (1980)
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    Optical and quantum electronics 12 (1980), S. 183-186 
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    A microprocessor-controlled apparatus for the measurement of pulsed spectra (1980)
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    Optical and quantum electronics 12 (1980), S. 193-197 
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    Notes: Abstract A simple and relatively inexpensive microprocessor-controlled apparatus to measure pulsed spectra has been developed. The system enables the average for a given number of pulses to be taken at each data point. Spectra of a mercury lamp are presented as an example.
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    X-ray production by a laser plasma in a strong electric field (1980)
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    Optical and quantum electronics 12 (1980), S. 231-235 
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    Notes: Abstract The X-ray emission of a laser plasma from metal targets in a 26 kV cm−1 electric field is investigated experimentally. A substructure of the X-ray pulse, corresponding to the laser pulse train period is found. The spectrum of the radiation in the range 2–25 keV is measured.
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    A geometrical optics treatment of differential mode delay (1980)
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    Optical and quantum electronics 12 (1980), S. 253-257 
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    Notes: Abstract We consider the problem of expressing the index of the refraction profile of a graded-index fibre or planar waveguide in terms of the results of differential mode delay measurements. We develop a perturbative solution to this problem within the context of geometrical optics by assuming that only meridional rays contribute experimentally.
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    Detuning effects of FM mode-locking in atmospheric CO2 lasers (1980)
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    Optical and quantum electronics 12 (1980), S. 259-268 
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    Notes: Abstract We describe a study of the detuning of the intracavity FM modulation of the homogeneously broadened laser applied to CO2 systems. The analysis is done by working in the frequency domain and by describing the field in terms of discrete amplitudes and phases. The coupled mode equations are solved for modulation frequencies near the axial mode-separation frequency. The asymmetry of the mode-locking behaviour due to the dispersive behaviour of the active medium is verified experimentally. We have measured both the pulse and the phase shift of the pulse with respect to the modulation signal as a function of detuning. The experimental results show clearly the asymmetry with detuning, in agreement with theory.
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    Pulse propagation in optical fibres with index profiles slowly varying along their length (1980)
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    Optical and quantum electronics 12 (1980), S. 281-290 
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    Notes: Abstract This paper describes the formalism for calculating the effect of profile variations along the fibre on transit times and path parameters for rays in multimode fibres. The ideal case of power-law profiles is considered in detail and it is shown that when the exponentq is given byq=q 0+εf (z), the fibre may be described by an equivalent exponentq e. Simple formulae forq e in terms of the average properties off(z) are given. The ray parameter $$\tilde \beta $$ varies and this is shown to have only a minor effect on transit time, but does imply that some rays suffer an attenuation whenε≠0. If the amount of dopant in any crosssection is assumed constant, the fibre radius must vary whenq varies and profiles with this attribute are examined and shown to have ray behaviour similar to that described above.
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    Theory of electric field-induced optical second harmonic generation in semiconductors (1980)
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    Optical and quantum electronics 12 (1980), S. 199-205 
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    Notes: Abstract The nonlinear optical coefficientd ij(kl) (2ω, 0,ω, ω) for electric field-induced optical second harmonic generation in semiconductors is calculated by means of a perturbation treatment. The result is given directly as a Brillouin zone integral over a resonant energy denominator. A simplified energy band structure model is used to carry out the Brillouin zone integral. The analytic closed-form expression ford ij(kl) (2ω, 0,ω, ω) thus obtained permits the calculation of the absolute value of its spectrum from available energy band parameters. The dispersion ofd 11(11) (2ω, 0,ω, ω) of Ge is numerically calculated, second harmonic photon energies being close to theE 0 andE 1 gaps. The results show pronounced resonant behaviours.
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    A ray approach to scattering in optical fibres (1980)
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    Optical and quantum electronics 12 (1980), S. 221-230 
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    Notes: Abstract The problem of scattering in optical fibres is approached by means of a ray theory and by considering both the parameters that characterize each ray congruence. Starting from a general transport equation a two-variable diffusion equation is derived and its field of validity is discussed. Preliminary results (steadystate power distribution among ray congruences; steady-state attenuation and steady-state length) are given in some simple but common cases. These results permit interesting comparisons with other theories.
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    Statistics of image plane speckle (1980)
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    Optical and quantum electronics 12 (1980), S. 237-243 
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    Notes: Abstract We examine the statistical properties of speckle patterns produced at an arbitrary axial point of a telecentric imaging system having a soft and hard-edged aperture. Expressions for the contrast of the pattern ar derived and discussed.
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    Laser isotope separation of 129/2 (1980)
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    Optical and quantum electronics 12 (1980), S. 269-272 
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    Economic evaluations and forecasts for optical fibre transmission systems at 1.2–1.5 μm (1980)
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    Optical and quantum electronics 12 (1980), S. 273-279 
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    Notes: Abstract Inherent characteristics of optical fibres make them suitable for telecommunication networks. This can become a matter of fact provided that costs of fibres and of related components make optical systems more convenient than copper cable ones. Economic evaluations of convenience limits, especially for systems operating at 1.2–1.5μm are given, as well as an estimate of the percentage of links in different areas of a typical network (in Italy) that can be realized without intermediate repeaters using optical fibres at 0.8–0.9μm or at 1.2–1.5μm.
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    Modal effects in the transmission method for index measurement in thick planar films (1980)
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    Optical and quantum electronics 12 (1980), S. 439-442 
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    First-order probability density function of the laser speckle phase (1980)
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    Optical and quantum electronics 12 (1980), S. 477-494 
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    Notes: Abstract An expression for the first-order probability density function of the laser speckle phase is analytically derived under the assumption that the speckle field obeys a non-circular, complex Gaussian, random process with a certain correlation between the real and imaginary parts of its complex amplitude. The probability density function of the speckle phase is actually evaluated for various cases and shown three-dimensionally as a function of the standard deviation of random object phase variations. The effect of random object phase variations on the probability density function is also investigated in detail.
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    Formation of laser speckles under extra-axial aberrations (1980)
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    Optical and quantum electronics 12 (1980), S. 519-524 
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    Comments on ‘modes in weakly guiding elliptical optical fibres’ (1980)
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    Optical and quantum electronics 12 (1980), S. 529-532 
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    An acousto-optic modulator for a CO2 laser rangefinder using heterodyne detection (1980)
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    Optical and quantum electronics 12 (1980), S. 419-426 
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    Notes: Abstract The ability to superimpose arbitrary modulation waveforms on a CW laser beam makes the acoustooptic modulator suitable for an important task: to apply modern microwave radar electronic signalprocessing and signal-generation techniques to heterodyne CO2 laser radar systems. The fundamental constraints on modulator design are first presented graphically in a novel treatment. The fabrication of 50–70 MHz germanium-lithium niobate modulators for a CO2 laser radar is then described. Experimental measurements of efficiency (about 4% per electrical watt transducer input power) and rise time (∼ 40 ns) are finally presented.
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    Polarization filtering in strip-guides (1980)
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    Optical and quantum electronics 12 (1980), S. 427-433 
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    Notes: Abstract The application of the cut-off effect in the building of polarizers in strip-guides is investigated. Different structures, already realized in the case of slab-guides, are considered. The dispersion curves of ion-exchanged glass strip-guides were computed by the effective-index method and were then used to model the investigated structures. The results obtained show that a cut-off polarizer can be relatively easily constructed in a strip-guide with only one transverse mode. In the multimode case the application of the investigated structures is often complicated and sometimes impossible.
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    A double pole, double throw electro-optic switch with an N-type electrode (1980)
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    Optical and quantum electronics 12 (1980), S. 525-527 
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    The non-linear Schrödinger equation and the non-stationary evolution of the intense localized wave field (1980)
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    Optical and quantum electronics 12 (1980), S. 95-102 
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    Notes: Abstract The possibility of the origin of the high intensity localized region near the wave pulse maximum is illustrated by means of exact solutions of the non-linear Schrödinger equation. The critical and supercritical regimes of wave pulse non-stationary evolution are illustrated. The tendencies of evolution depend essentially upon the initial profile of the pulse.
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    Influence of fluctuations of a laser pump on the intensity correlation of resonance fluorescence radiation (1980)
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    Optical and quantum electronics 12 (1980), S. 65-76 
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    Notes: Abstract The influence of fluctuations of a relatively weak laser pump on the intensity correlation of resonance fluorescence radiation is studied for a laser acting both below and above the threshold. Below the threshold the radiation of the laser is characterized by Gaussian properties causing non-factorization of the intensity correlation function. Above the threshold the laser shows non-linear filter properties and, therefore, the deviation of the exact intensity correlation function from its factorized value is small.
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    Effects of thin film overlays on the mode properties of ion-exchanged guide (1980)
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    Optical and quantum electronics 12 (1980), S. 80-83 
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    Fibre switch of 1*93: an experimental trial (1980)
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    Optical and quantum electronics 12 (1980), S. 87-90 
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    On-line codes for digital optical communications (1980)
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    Optical and quantum electronics 12 (1980), S. 91-93 
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    Radiation losses due to discontinuities in asymmetric three-layer optical waveguides (1980)
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    Optical and quantum electronics 12 (1980), S. 143-158 
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    Notes: Abstract In this paper, the radiation losses caused by film thickness and refractive index discontinuities in asymmetric slab waveguides are examined theoretically. A technique developed by Mahmoud and Beal for dealing with the continuous part of the radiation spectrum is used. Several numerical examples which show the radiation loss for various waveguide configurations are presented and discussed and, where appropriate, comparisons with other related work made. In the case of asymmetric thickness steps, the radiation losses are found to be appreciably higher than those computed for symmetric guides. The radiation losses for guides having the same thickness were found to decrease as the guide thickness increased. Once the TE1 mode become guided, the losses decreased rapidly. However, if the two guides had different thickness then it was found that the losses exhibited a minimum.
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    Amorphous As2 S3 thin film waveguide with grating coupler (1980)
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    Optical and quantum electronics 12 (1980), S. 179-181 
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    An optimized technique for backscatter attenuation measurements in optical fibres (1980)
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    Optical and quantum electronics 12 (1980), S. 169-178 
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    Notes: Abstract A technique which gives maximum range and sensitivity for estimating fibre attenuation from the backscattered light has been evolved. With this technique stability problems in the source and receiver are overcome by taking two different time samples for each pulse launched into the fibre, the attenuation being derived from the ratio of the two samples. An analysis indicates that an optimum operating strategy exists in terms of the choice of system parameters such that the range over which attenuation can be measured is maximized. Results indicate that local loss measurements can be performed on fibre sections which are remote from the source by a distance corresponding to a fibre attenuation of 27 dB. Furthermore, preliminary experimental results are presented to demonstrate the viability of the technique.
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    Optical waveguide theory (1980)
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    Optical and quantum electronics 12 (1980), S. 187-191 
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    Notes: Abstract This report summarizes the activites at the 4th International Workshop on Optical Waveguide Theory, held at Leuwenhorst Holland on 13–16 September 1979.
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    Intrinsic noise of semiconductor lasers in optical communication systems (1980)
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    Optical and quantum electronics 12 (1980), S. 207-219 
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    Notes: Abstract The upper limit of the achievable signal-to-noise ratio in optical communication systems is determined by the intrinsic laser noise due to quantum fluctuations inside the laser cavity. This achievable signal-to-noise ratio depends on the way in which different lasing modes are detected; wavelength filtering and material dispersion may yield a significant deterioration of the signal-to-noise ratio. It is concluded from theoretical calculations and from measurements on V-groove lasers that a d.c. signal-to-noise ratio of about 70 dB may be achieved for a noise bandwidth of 10 MHz.
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    Self-locked He-Ne ring laser (1980)
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    Optical and quantum electronics 12 (1980), S. 309-313 
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    Notes: Abstract Experimental conditions necessary for self-pulsing to occur in a He-Ne ring laser are reported. These results are compared with predictions that are based upon theoretical models that have been presented in the literature. Good qualitative agreement is found in that theory and experiment both show that self-pulsing will only occur over a range of excitation. Quantitative results differed enough to indicate that additional refinement is needed even though the models have identified many of the important parameters involved.
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    The reference range for differential absorption lidars (1980)
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    Optical and quantum electronics 12 (1980), S. 335-340 
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    Notes: Abstract The concept of reference range for lidars is extended to the case of differential absorption lidars. A method for determining the wavelengths of operation, optimal from the point of view of maximum reference range for uniform and non-uniform absorbant distribution, is presented.
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    Optical fibre profiling using a scanning optical microscope (1980)
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    Optical and quantum electronics 12 (1980), S. 341-345 
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    Notes: Abstract A scanning optical microscope is used to measure directly the refractive-index profile of an optical fibre. The effects of illuminating the fibre end with a highly convergent beam of light are considered.
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    Coherence effects in a multiply pumped spin-flip Raman laser (1980)
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    Optical and quantum electronics 12 (1980), S. 303-308 
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    Notes: Abstract A spin-flip Raman laser is fed simultaneously with two or more output frequencies of the CO pump laser. Not only are resonance effects seen when the magnetic field is tuned so that the Raman frequency equals the difference of two pump frequencies, but also when higher order resonances involving the sums and differences of CO lines equal the Raman frequency. The sign and intensity of these effects are briefly discussed and it is pointed out that the effects could be useful for calibration purposes.
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    Multiphoton detectors of laser radiation (1980)
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    Optical and quantum electronics 12 (1980), S. 291-301 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The paper is devoted to the problem of using multiphoton detectors to measure the statistical characteristics of multifrequency laser radiation affecting the nonlinear interaction between radiation and matter. Section 1 gives the characteristics of laser radiation determining the probability of power-type nonlinear interaction with a medium. Section 2 briefly characterizes multiphoton detectors. Sections 3–6 are devoted to the problems of measuring the so-called statistical radiation factor by means of multiphoton detectors and to the analysis of the corresponding experimental data. The possibility of using multiphoton detectors to measure other radiation characteristics is discussed in Sections 7 and 8.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00620283
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    On the spectra of resonant coherent Raman scattering (1980)
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    Optical and quantum electronics 12 (1980), S. 315-325 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The spectra of resonant coherent anti-Stokes and Stokes Raman scattering of excited molecules are calculated and discussed. The interaction of light and molecules is treated semi-classically. The energy level diagram of four energy levels describing the process is used in four modifications possible for excited molecules. It is shown that non-vibrational resonances give ‘extra’ maxima in some of the spectra. Comparison of the spectral structure in the Stokes and anti-Stokes components gives information on which of the four schemes the interaction is realized by. The influence of the pumping detuning on the Stokes component shape is pointed out.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00620286
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    Air pollution monitoring with a computer-controlled CO2-laser long-path absorption system (1980)
    Springer
    Optical and quantum electronics 12 (1980), S. 327-334 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract A CO2-laser long-path absorption system has been developed. It is highly automated with computer-controlled laser-line selection and real-time data processing. The system has been used to monitor ethylene and vinyl chloride concentrations over a petrochemical factory area. The ethylene concentrations ranged from below 0.02 ppm to 45 ppm. The vinyl chloride concentrations were less than 0.05 ppm. Different path lengths from 20 m to 2800 m were used. The minimum detectable ethylene concentration was typically 15 ppm m.
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    URL: http://dx.doi.org/10.1007/BF00620287
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    Editorial (1980)
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    Optical and quantum electronics 12 (1980), S. 351-351 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00620096
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    Wide-band optical fibre local distribution systems (1980)
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    Optical and quantum electronics 12 (1980), S. 353-381 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The concept of a wide-band optical local network is presented and the technical aspects are discussed in detail. The types of service are outlined and grouped according to the requirements for transmission capacity. The components available and their characteristics are presented. The modulation characteristics of the semiconductor laser are scrutinized and show that the laser is unfit for high-quality analogue intensity modulation. The aspects of digital and analogue transmission of television are examined and compared. Analogue transmission can provide transmission of only a few TV channels at the present level of quality whereas digital transmission can provide improved quality with a comfortable system margin. However, none of the schemes are suited for simultaneous transmission of many TV channels, which shows that the direct optical equivalent of a conventional CATV network cannot yet be constructed. The concepts of central switching and customer switching are outlined together with the options for multiplexing and network structure. Finally a review is made of known activities. The review covers eleven studied, planned and implemented experimental networks. Nearly all of the networks employ central switching. The older experiments use exclusively analogue transmission whereas there is a growing tendency to use digital transmission in recently planned networks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00620097
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    Cavity-dumping a mode-locked TEA CO2 laser (1980)
    Springer
    Optical and quantum electronics 12 (1980), S. 347-349 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00620290
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    Spectral properties of dye lasers (1980)
    Springer
    Optical and quantum electronics 12 (1980), S. 393-411 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract Starting from conventional rate equations describing the multimode operation of a laser with a broad homogeneous emission line, a system of approximately valid equations, suitable for both analytical and numerical studies of the spectral properties of laser radiation not too far from threshold, has been derived by introducing equations of motion for the spatial Fourier components of the inversion densityN(z, t), thus replacing the equation of motion forN(z, t) itself. Analytical solutions for steady-state operation were found and physically discussed in the following cases: (a) ring laser, (b) jet-stream laser with the active medium positioned either near one of the (Fabry-Perot) resonator mirrors or in the centre of the resonator, and (c) laser with a Fabry-Perot resonator completely filled with the active medium. The spectra thus calculated indicate that spatial hole burning is most efficient in providing mode co-existence in configuration (c), where it gives rise to a significant bandwidth. It is of minor importance, however, in case (b), where the spectrum differs only slightly from that of a ring laser, which is clearly free from hole-burning effects.
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    URL: http://dx.doi.org/10.1007/BF00620099
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    The third-order electric susceptibilities of NaCl and KCl monocrystals (1980)
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    Optical and quantum electronics 12 (1980), S. 443-447 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The dispersion of the third-order electric susceptibilitiesχ(ω; ω, ω, −ω) andχ(ω; ω, 0, 0) of NaCl and KCl monocrystals has been calculated by means of experimental data on the electro-optic Kerr effect. The result has been obtained by using semi-classical models of anharmonic oscillators. An ionic contribution to the electro-optic coefficients has been presented. From the result obtained it follows that the third-order electric susceptibilities are of the order of 10−22 m2 V−2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00619918
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    Optical beam and pulse propagation in inhomogeneous media. Application to multimode parabolic-index waveguides (1980)
    Springer
    Optical and quantum electronics 12 (1980), S. 463-475 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The integrals-of-motion method, the coherent states method, the method of the dynamical symmetry group, as well as the density matrix formalism, are used for the description of paraxial optical beam and pulse propagation in a weakly inhomogeneous medium. The formalism developed is then applied to a parabolic-index medium with bent axis of symmetry in which the index distribution varies along the direction of propagation. Expressions for beam trajectory and width as well as for r.m.s. pulse width are obtained. It is shown that certain particular longitudinal dependences of the index distribution function do not influence beam parameters. This phenomenon is used to achieve matching when two different parabolic-index waveguides are to be butt-joined. The connection of two parabolic-index waveguides with axis displacement is also discussed as an example and comparison between theoretical results and experimental data is made.
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    URL: http://dx.doi.org/10.1007/BF00619920
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    Anomalous group delay in optical fibres (1980)
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    Optical and quantum electronics 12 (1980), S. 511-517 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract It is shown, by means of computation on a specific model, how pulse broadening in multimode gradedindex optical waveguides is significantly affected by the levels of excitation of the high-order modes. Pulse widths are computed as functions of the profile parameterα, under conditions of equal excitation, high-order mode suppression and GaAs laser excitation.
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    URL: http://dx.doi.org/10.1007/BF00619924
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    Space-time response of a cloud communication channel to an optical signal (1980)
    Springer
    Optical and quantum electronics 12 (1980), S. 499-509 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract An optical signal,an impulse in space and step in time,is incident on a plane,parallel fixed,homogeneous cloud. The incident signal is modelled as a stream of photons, each of them executing a random walk. A Monte Carlo simulation technique is applied to obtain the space-time response of the channel when an optical receiver with a specified field of view is located at a specified distance below the cloud. The response is obtained as angular, spatial and temporal dispersions. Various simulation steps are described. For thin clouds two variance reduction techniques, i.e. Russian roulette and forced collision, are used. It is shown that the bottom of the cloud tends to diffuse uniformly and the 3 dB exit beam width saturates. The rise time in this channel is found to be of the order of several nanoseconds.
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    URL: http://dx.doi.org/10.1007/BF00619923
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    Phenomenological rules for the computation of magneto-electric susceptibilities (1980)
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    Optical and quantum electronics 12 (1980), S. 103-107 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract Applying the model of the anharmonic oscillator, phenomenological expressions were derived, allowing calculation of the components of tensors describing non-linear magneto-electric susceptibilities. Detailed calculations were carried out for the pseudo-tensor of fourth order ηeeem in terms of which magneto-optical birefringence and rotation are expressed for the monocrystals KDP, DKDP, ADP, KDA, LiNbO3, LiTaO3 and NaClO3. From the results obtained it follows that non-linear magneto-electric susceptibilities, which are described by the pseudo-tensor ηeeem are of the order of 10−16 m V−1T−1.
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    URL: http://dx.doi.org/10.1007/BF00619554
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    Reduction of optical damage effects in LiNbO3 and LiTaO3 (1980)
    Springer
    Optical and quantum electronics 12 (1980), S. 495-498 
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    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract Optical damage effects in electro-optic crystals such as LiNbO3 and LiTaO3 result from light-induced refractive index changes which bring about decollimation and scattering of light beams. The origin of the index changes is discussed. Although it is currently impossible to avoid undesired optical damage completely, various possibilities are proposed to reduce the effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00619922
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    Design of electrochemical reactors via a sequential factorial costing technique (1980)
    Springer
    Journal of applied electrochemistry 10 (1980), S. 13-24 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A simplified procedure for the design of electrochemical reactors based on Lang factors as a general strategy for assigning priorities in the assessment of costs and relative importance of process parameters is described. The importance of reactor geometry and its sensitivity to variation in cost components is illustrated by a specific industrial-scale design of a rotating bipolar cell equipped with wiper blades. The technique is applicable to any type of electrochemical cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00937332
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