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  • Springer  (148)
  • 2000-2004  (95)
  • 1990-1994  (51)
  • 1890-1899  (2)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    Elimination of the nonminimum-phase problem at major sampling intervals (1992)
    Springer
    Circuits, systems and signal processing 11 (1992), S. 309-324 
    Details
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Dual time-scale sampling with intermediate discrete filtering, called moving-average skip sampling, is introduced to overcome the problem of unstable zeros of the sampled system. The new scheme proves easy to implement and efficiently recovers the minimum-phase property of the continuous system at major sampling intervals. An example illustrates the effect of moving-average skip sampling on the nonminimum-phase zeros.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01293678
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  • 2
    Electronic Resource
    Electronic Resource
    Intramolecular Alkyne Coupling in the Reaction of 1,8-bis(phenylethynyl)naphthalene with Pt2Ru4(CO)18 (2000)
    Springer
    Journal of cluster science 11 (2000), S. 55-65 
    Details
    ISSN: 1572-8862
    Keywords: bis(phenylethynyl)naphthalene ; ruthenium ; platinum ; alkyne coupling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The reaction of Pt2Ru4(CO)18, 1 with 1,8-bis(phenylethynyl)naphthalene, 2 has yielded two metal carbonyl cluster complexes: Ru2(CO)6[μ-η 2-C10H6C4Ph2], 3 (60% yield) and Ru2Pt(CO)6[μ-η 2-C10H6C4Ph2]2, 4 (8% yield). Both compounds were characterized by a single crystal X-ray diffraction analysis. Both products were formed as a result of fragmentation of the Pt2Ru4 cluster of 1. Compound 3 contains two ruthenium atoms. They are bridged by a tricyclic C10H6C4Ph2 ligand formed by the coupling of the two α-carbon atoms of the alkyne groups. The β-carbon atoms of the alkynes are σ-bonded to one of the ruthenium atoms to form a metallacycle and this entire group is π-bonded to the second ruthenium atom. Compound 4 contains two ruthenium atoms with a platinum atom between them. This molecule contains two tricyclic C10H6C4Ph2 ligands similar to that in 3, and two metallacycles formed by coordination of the β-carbon atoms of both ligands to the platinum atom. One ligand is π-bonded to each of the ruthenium atoms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009052412595
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  • 3
    Electronic Resource
    Electronic Resource
    Catalytic behaviour of metal ions located at different sites of heteropolycompounds (1994)
    Springer
    Catalysis letters 23 (1994), S. 195-205 
    Details
    ISSN: 1572-879X
    Keywords: H2O2-decomposition ; heteropolycompounds ; Keggin structure ; Dawson structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract It was discovered experimentally that heteropolymolybdophosphoric acids (HPA) with Keggin and Dawson structure are inactive for H2O2-decomposition, while their salts (Fe3+, Cu2+, Co2+ and Mn2+) all possess more activity. It could be concluded that the active species is the countercation of these kinds of heteropolymolybdates. The molybdenum ions in the polyanions are not active. If the molybdenum ions in the polyanions of these acids are substituted partly by vanadium ion (HPA-n), then not only does the catalytic activity increase regularly with the number of vanadium ions substituted (n) but the kinetic curve is also different from that of the salt, characterized by an S-shape, indicating the formation of an active intermediate as a result of the reaction between the polyanion of HPA-n and the substrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00812148
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  • 4
    Electronic Resource
    Electronic Resource
    Role of dissolution of Mn(iii) species in discharge and recharge of chemically-modified MnO2 battery cathode materials (1993)
    Springer
    Journal of applied electrochemistry 23 (1993), S. 693-706 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Various experimental techniques, including cyclic-voltammetry, constant current discharge and recharge, with a detecting electrode for determination of soluble Mn(iii) intermediate species, were used to study the reaction mechanism involved in the reduction of a chemical modified form of MnO2 that is multiply rechargeable. The results show how dissolution of Mn(iii) species plays an important role in the overall path of the reduction reaction and also in the rechargeability of the material. Mainly an heterogeneous reduction mechanism is involved; substantial loss of capacity can arise if diffusion of the soluble Mn(iii) species into the bulk electrolyte solution is allowed to take place. In practical cells, this effect must be minimized using cells with ‘starved electrolyte’, i.e. with only a small free volume-fraction of KOH electrolyte in the MnO2-carbon electrode structure. Soluble Mn(iii) species were detected in in situ experiments by means of (a) a spectro-electrochemical procedure, (b) a ‘collector’ electrode system at which dissolved Mn(iii) was reoxidized to MnO2, and (c) a rotating ring-disc electrode.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00243339
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  • 5
    Electronic Resource
    Electronic Resource
    Phyletic relationships of protein structures based on spatial preference of residues (1993)
    Springer
    Journal of molecular evolution 36 (1993), S. 67-78 
    Details
    ISSN: 1432-1432
    Keywords: Structure-based scoring matrix MDPRE ; Phyletic relationship of protein structure ; Spatial preference factor ; Sequence alignment ; Protein homology detect ; Globins ; Immunoglobulins ; Cytochromes c ; Serine proteinases ; Dinucleotide-binding domains
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A structure-based scoring matrix MDPRE was derived from amino acid spatial preferences in protein structures. Sequence alignment and evolutionary studies by using MDPRE matrix gave similar results as those from ordinary sequence and structure alignments. It is interesting that a matrix derived from structure data solely could give comparable alignment results, strongly indicating the intimate connection between protein sequences and structures. The branch order and length from this approach were close to those obtained by a structure comparison method. Thus, by applying this structure-based matrix, the trees obtained should reflect evolutionary characteristics of protein structure. This approach takes advantage over a direct structure comparison in that (1) only a sequence and MDPRE matrix are needed, making it simple and widely applicable (especially in the absence of 3-dimensional protein structure data); (2) an established algorithm for sequence alignment and tree building could be employed, providing opportunities for direct comparison between matrices from different methodologies. One of the most striking features of this method is its capability to detect protein structure homologies when the sequence identities are low. This was well reflected in the given examples of the alignment of dinucleotidebinding domains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02407306
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  • 6
    Electronic Resource
    Electronic Resource
    On the robust control of two manipulators holding a rigid object (1992)
    Springer
    Journal of intelligent and robotic systems 6 (1992), S. 107-119 
    Details
    ISSN: 1573-0409
    Keywords: Multiple manipulators ; robust control ; position/force control ; robot modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In this paper, a control architecture is developed for the closed chain motion of two six-joint manipulators holding a rigid object in a three-dimensional workspace. Dynamic and kinematic constraints are combined with the equations of motion of the manipulators to obtain a dynamical model of the entire system in the joint space. Reduced-order dynamic equations are then developed with regard to the position and force control variables. Robust control laws are then determined such that the force and position control design is decoupled. The control laws that will be discussed are: a robust position tracking controller that yields an exponentially stable position tracking error result, and a robust force tracking controller that yields adjustable bounds on the force tracking error.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00314701
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  • 7
    Electronic Resource
    Electronic Resource
    On the learning control of a robot manipulator (1991)
    Springer
    Journal of intelligent and robotic systems 4 (1991), S. 43-53 
    Details
    ISSN: 1573-0409
    Keywords: Robots ; control ; learning ; tracking control ; computed-torque control ; robustness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper derives a learning control law to achieve trajectory following for a robot manipulator. The controller consists of two parts, a computed torque servo for the rigid body terms that can be modelled and a learning law for the unmodelled dynamics. An advantage of this method is that bounds can be assigned to the position and velocity tracking errors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00452101
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  • 8
    Electronic Resource
    Electronic Resource
    Position and force tracking control of rigid-link electrically-driven robots (1994)
    Springer
    Journal of intelligent and robotic systems 10 (1994), S. 173-190 
    Details
    ISSN: 1573-0409
    Keywords: Rigid-link robot manipulator ; DC actuator ; position and force tracking control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper introduces a framework for the design of tracking controllers for rigid-link electrically-driven (RLED) robot manipulators operating under constrained and unconstrained conditions. We present an intuitive nonlinear control strategy that can easily be reformulated for robots performing high precision tasks. The main emphasis is placed on the development of controllers that incorporate both motion in freespace and under constrained conditions. Another novelty is the combined treatment of force control and compensation for actuator dynamics. Based on models of the robot dynamics and environmental constraints, a reduced order dynamic model is obtained for the mechanical subsystem with respect to a set of constraint variables. A design procedure for tracking controllers is then formulated for the reduced order manipulator dynamics and the DC actuator dynamics. This paper concentrates on the theoretical aspects of the problem and, hence, is based on exact knowledge of the entire system. However, we have illustrated recently in [1] that this assumption can be generously relaxed in the design of a robust controller following a similar procedure as discussed in this paper.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01258227
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  • 9
    Electronic Resource
    Electronic Resource
    FGTO — A fine structured GTO-thyristor with improved switching characteristics (1991)
    Springer
    Electrical engineering 74 (1991), S. 433-444 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Zur Verbesserung des Schaltverhaltens ist ein feinstrukturierter GTO-Thyristor, abgekürzt FGTO, entwickelt worden. Dieses neue Bauelement hat eine Kathoden-streifenbreite von nur 20 μm und kann ohne negative Gatevorspannung bei einer Anodenstromdichte von mehr als 200 A/cm2 abgeschaltet werden. Die Abschaltzeit läßt sich durch Erhöhung des negativen Gatestroms bis zut off ≦500 ns verkürzen. Beim Abschalten von FGTOs ist keine RC-Beschaltung erforderlich. Der maximale du/dl-Wert erreicht mehr als 10 kV/μs. Zur Beschreibung des Abschalt-verhaltens von FGTOs werden analytische Modelle entwickelt, die eine gute Übereinstimmung mit den Meßergebnissen liefern.
    Notes: Contents A fine structured GTO thyristor, abbreviated FGTO, has been developed to improve the switching characteristics. The new device has a cathode finger width of only 20 μm and can be turned off without a negative gate bias at an anode current level of more than 200 A/cm2. The turn-off time can be shortened down tot off ≦500 ns by increasing the negative gate current. A snubber circuit is not necessary to turn off the FGTO's. The maximum rate of rise of anode voltage du/dl reaches more than 10 kV/μs. Analytical models are developed to describe the turn-off transients of the FGTO's. Good agreement between the theoretical and experimental results could be achieved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01577465
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  • 10
    Electronic Resource
    Electronic Resource
    Experimental and theoretical study of the turn-off behavior of field-controlled thyristors (FCTh's) (1992)
    Springer
    Electrical engineering 75 (1992), S. 359-367 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Es wird das Abschaltverhalten von FCTh's mit Oberflächen-Gates untersucht. Die verwendeten Bauelemente weisen Abschaltzeiten von weniger als 300 ns auf. Gemessen werden die transienten Verläufe von Anodenstrom, Gatestrom und Anodenspannung bei ohmscher und induktiver Last. Zur Beschreibung des Abschaltverhaltens werden neue analytische Modelle erstellt. Berechnungen der Abschaltverzugsphase unter Berücksichtigung transienter Gatestromverläufe und der Tailphase unter Berücksichtigung der Rekombination in derp +-Anodenzone werden durchgeführt.
    Notes: Contents The turn-off behavior of FCTh's with surface-gates is studied. The devices investigated in this paper exhibit short turn-off times of less than 300 ns. The anode current, gate voltage and anode voltage are measured under resistive and inductive load. Analytical models are developed to describe the turn-off transients of the FCTh's. Studies of the storage phase including the time-dependent gate current and the tail period including the recombination in thep +-anode region have been perfomed by applying the new models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01576106
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