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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Optical and quantum electronics 27 (1995), S. 203-224 
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract A modal noise model is presented that combines many features of previous theories such as varying fibre contrast, exponential noise p.d.f. and Gaussian noise p.d.f. The model also includes a new feature: the ability to treat multiple lossy connectors in the same link. This model is verified through extensive experimentation and is shown to be conservative, i.e. predicted noise penalties are larger than those observed. Using the model, modal noise penalties are predicted for a number of different link configurations, and laser parameters that result in acceptable amounts of modal noise are identified. The model is also demonstrated as a design tool for determining laser parameters that result in acceptable amounts of modal noise in typical links.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Optical and quantum electronics 26 (1994), S. S219 
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstact We present a numerical method for solving a set of coupled mode equations describing light propagation through a medium with a grating and free carriers. The carriers, which are excited by the light and decay exponentially in time, lower the refractive index, thus rendering the system nonlinear. The method is fourth-order accurate, efficient, stable, easy to implement and well suited for vector and parallel computers.
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  • 3
    ISSN: 1572-9125
    Keywords: Initial value problem ; ordinary differential equation ; Runge-Kutta method ; order ; internal stage values ; iterative scheme ; Newton's method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract We employ B-series to analyze the order of Runge-Kutta (RK) methods that use simple iteration, modified Newton iteration or full Newton iteration to compute their internal stage values. Our assumptions about the initial guess for the internal stage values cover a wide range of practical schemes. Moreover, the analytical techniques developed in this paper can be applied in many other similar contexts.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1858
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Technology
    Notes: Abstract  We are fabricating sub-collimating X-ray grids that are to be used in an orbiting solar X-ray telescope. The telescope optics consist of twelve rotating pairs of high aspect ratio grids. The pitch for the grids ranges from 34 μm to 317 μm. The grid thickness-to-grid-slit ratio must be approximately 50:1, resulting in grid thicknesses of 1 to 10 millimeters. We are implementing a design in which a 34 μm pitch, free-standing PMMA grid is fabricated with 20 μm wide slits through a 800 μm thickness. After exposure and developing, metal is electrodeposited into the slits in the PMMA grid and the PMMA is left in place to hold the individual metal pieces. For optimum imaging performance, the root-mean-square pitch of the two grids of each pair must match to within 1 part in 10000 and simultaneous exposures of stacked sheets of PMMA have insured that this requirement is met.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 32 (1997), S. 5035-5045 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Indentation hardness and three-point bend tests were performed on perforated synthetic diamond substrates designed for use in a three-dimensional cube computer architecture based on interconnected stacking of multichip modules. The fracture strengths in bending of two substrate materials, with and without laser drilled interconnect “via holes”, were correlated with optical and scanning electron microscope (SEM) observations of the fracture surfaces, thus providing for matching of fracture strengths with different growth microstructures within the plates and, also, with the extent of weakening produced by the via holes. The relatively high strength levels, characteristic of diamond material, were found to be lowered somewhat either by a filamentary pattern of growth fissures in one material or less so by apparent cleavage fracturing among textured grains in a second material. In the latter case, the technique of fracture surface topography analysis (FRASTA) provided evidence of plastic flow having occurred during fracturing.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 262 (1999), S. 830-838 
    ISSN: 1617-4623
    Keywords: Key wordsArabidopsis thaliana ; Cyclophilins ; Protein phosphatase 2A ; Protein phosphatase 2B ; Root growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The heterotrimeric protein phosphatase 2A (PP2A) is a component of multiple signaling pathways in eukaryotes. Disruption of PP2A activity in Arabidopsis is known to alter auxin transport and growth response pathways. We demonstrated that the regulatory subunit A of an Arabidopsis PP2A interacts with a novel cyclophilin, ROC7. The gene for this cyclophilin encodes a protein that contains a unique 30-amino acid extension at the N-terminus, which distinguishes the gene product from all previously identified Arabidopsis cyclophilins. Altered forms of ROC7 cyclophilin with mutations in the conserved DENFKL domain did not bind to PP2A. Unlike protein phosphatase 2B, PP2A activity in Arabidopsis extracts was not affected by the presence of the cyclophilin-binding molecule cyclosporin. The ROC7 transcript was expressed to high levels in all tissues tested. Expression of an ROC7 antisense transcript gave rise to increased root growth. These results indicate that cyclophilin may have a role in regulating PP2A activity, by a mechanism that differs from that employed for cyclophilin regulation of PP2B.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Virtual reality 3 (1998), S. 147-156 
    ISSN: 1434-9957
    Keywords: Wearable computer ; Information tool ; Mobile computer ; Wireless networking ; Voice recognition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The wearable computer is a portable computer that is actually worn on the user's body. Ergonomics is therefore a vital feature of its design. Since humans naturally communicate with voice, a wearable computer also responds to the voice. Wearable computers and global wireless networks make it possible to bring exciting capabilities to the individual. Until recently, wearable computer development has been restricted to academic and military laboratories. Now, technological advances and reduced cost have ignited investor excitement about wearable computers. Wearable system applications in manufacturing, logistics, medicine, training, quality control, communications and even entertainment are now becoming widespread. The earliest development of wearable computers occurred in the 1960s. All of the elements of the modern wearable computer were in place in the Eudaemons system for predicting outcome on a roulette wheel. Since then, wearable computer development has paralleled advances in microprocessor technology. After addressing the important distinction between wearable and mobile computers, this paper will look at wearable computers as an information tool for industry. A short history of wearable computers will trace development from the early single application attempts to today's feature-rich systems. A discussion on current and anticipated applications is then followed by an overview of important related technologies. Finally, the paper will assess how wearable computers could impact twentyfirst century industry and society.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Medical & biological engineering & computing 15 (1977), S. 446-449 
    ISSN: 1741-0444
    Keywords: Goniometer ; Radio-frequency transducers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Description / Table of Contents: Sommaire Cet article pose les grandes lignes d'une méthode de détermination des changements d'angle des articulations pour un mouvement des membres dans un plan donné. Le transducteur décrit possède une linéarité acceptable sur 100°. Il constitute une solution utile en remplacement de la goniométrie dans les cas où la fixation d'un goniomètre sur l'articulation interfère trop avec le mouvement étudié. Le transducteur détecte les mouvements spatiaux en mesurant le voltage induit dans une bobine détectrice par un champ magnétique de 1 MHz produit par un petit solénoïde. L'article discute également de la détection des mouvements du corps en trois dimensions et montre qu'elle est possible avec un système plus complexe.
    Abstract: Zusammenfassung Dieser Aufsatz umreißt eine methode zur Überwachung von Änderungen im Gelenkwinkel bei einer zweidimensionalen Bewegung der Gliedmaßen. Der beschriebene Umformer ist annehmbar linear über einen Bereich von 100°. Es handelt sich um eine nützliche Alternative zur Winkelmessung in Situationen, in denen ein über dem Gelenk angebrachter Goniometer die zu studierende Bewegung unangemessen stören würde. Der Umformer stellt räumliche Bewegung fest, indem er die Spannung mißt, die von einem 1 MHz-Magnetfeld, das von einer kleinen Magnetspule erzeugt wird, in eine Fühlspule induziert wird. Die dreidimensionale Überwachung von Körperbewegungen wird diskutiert und deren Durchführbarkeit unter Verwendung eines komplizierteren Systems nachgewiesen.
    Notes: Abstract The paper outlines a method of monitoring changes in joint angle for a 2-dimensional movement of the limbs. The transducer described is acceptably linear over a range of 100°. It provides a useful alternative to goniometry in situations where the attachment of a goniometer across the joint would cause undue interference to the movement being studied. The transducer detects spatial movement by measuring the voltage induced in a sensing coil from a 1 MHz magnetic field produced by a small solenoid. 3-dimensional monitoring of body movements is discussed and shown to be feasible using a more complex system.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 346-348 
    ISSN: 1434-6079
    Keywords: 36.40 ; 31.20.Sy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have investigated two generic structural models for Si clusters in the size range 20–33 atoms. The first model consists of stacks of puckered six-fold rings, with capping atoms on the two ends. The second model comprises compact structures with as many bulk-like four-fold coordinated atoms as possible. We have found the cohesive energy of the ring structures to be nearly constant as a function of cluster size, while that of the compact structures decreases dramatically with increasing size as more four-fold coordinated atoms are incorporated into the structures. We compare our results with recent experiments which suggest a crossover in stability between two cluster types in the size range studied here.
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