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  • 1
    Electronic Resource
    Electronic Resource
    Absence of magnetic order in (Ba, K)BiO 3 (1988)
    [s.l.] : Nature Publishing Group
    Nature 335 (1988), S. 151-152 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1 Muon spin precession signal observed a, in a non-superconducting specimen of (Ba, K)BiO3 at T = 3.4K by applying a transverse external magnetic field Hext= 125 G, and b, in an anti-ferromagnetic YBa2Cu3C〉6 18 at T = 276 K with Hext = 100 G. The muon decay-time histogram is given as N(t) = ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/335151a0
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  • 2
    Electronic Resource
    Electronic Resource
    Automated fuzzy knowledge acquisition with connectionist adaptation (1996)
    Springer
    Neural computing & applications 4 (1996), S. 27-34 
    Details
    ISSN: 1433-3058
    Keywords: Fuzzy logic ; Genetic algorithms ; Knowledge acquisition ; Learning ; Neural networks ; Optimisation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract This paper presents an automated knowledge acquisition architecture for the truck docking problem. The architecture consists of a neural network block, a fuzzy rule generation block and a genetic optimisation block. The neural network block is used to quickly and adaptively learn from trials the driving knowledge. The fuzzy rule generation block then extracts the driving knowledge to form a knowledge rule base. The driving knowledge rule base is further optimised in the genetic optimisation block using a genetic algorithm. Computer simulations are presented to show the effectiveness of the architecture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01413867
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  • 3
    Electronic Resource
    Electronic Resource
    An RBF neural network-based adaptive control for SISO linearisable nonlinear systems (1998)
    Springer
    Neural computing & applications 7 (1998), S. 71-77 
    Details
    ISSN: 1433-3058
    Keywords: Adaptive control ; Linearisable nonlinear system ; Lyapunov stability ; RBF neural network ; Uncertain dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract An RBF neural network-based adaptive control is proposed for Single-Input and Single-Output (SISO) linearisable nonlinear systems in this paper. It is shown that a SISO nonlinear system is first linearised by using the differential geometric approach in the state space, and the linearised nonlinear system is then treated as a partially known system. The known dynamics are used to design a nominal feedback controller to stabilise the nominal system, and an adaptive RBF neural network-based compensator is then designed to compensate for the effects of uncertain dynamics. The main function of the RBF neural network in this work is to adaptively learn the upper bound of the system uncertainty, and the output of the neural network is then used to adaptively adjust the gain of the compensator so that the strong robustness with respect to unknown dynamics can be obtained, and the tracking error between the plant output and the desired reference signal can asymptotically converge to zero. A simulation example is performed in support of the proposed scheme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01413711
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  • 4
    Electronic Resource
    Electronic Resource
    An Adaptive Control Using Fuzzy Basis Function Expansions for a Class of Nonlinear Systems (1998)
    Springer
    Journal of intelligent and robotic systems 21 (1998), S. 257-275 
    Details
    ISSN: 1573-0409
    Keywords: fuzzy basis function ; adaptive control ; nonlinear systems
    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 An adaptive control using fuzzy basis function expansions is proposed for a class of nonlinear systems in this paper. It is shown that two system uncertainty bounds are approximated in a compact set by using fuzzy basis function expansion networks in the Lyapunov sense, and the outputs of the fuzzy networks are then used as the parameters of the controller to adaptively compensate for the effects of system uncertainties. Using this scheme, not only strong robustness with respect to unknown system dynamics and nonlinearities can be obtained, but also the output tracking error between the plant output and the desired reference output can be guaranteed to asymptotically converge to zero. Simulation results are provided to demonstrate the effectiveness, simplicity and practicality of the proposed control scheme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007962117548
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  • 5
    Electronic Resource
    Electronic Resource
    Direct production of ultrafine amorphous Fe-P alloy particles by the plasma method (1995)
    Springer
    Journal of materials science 30 (1995), S. 2911-2920 
    Details
    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 Ultrafine amorphous Fe-P alloy particles were directly synthesized by the plasma using cyclopentenyl iron and phosphorous trichloride as starting materials. The plasma gas greatly influenced the morphology, dispersion and composition.The particles were roughly spherical with a diameter of 40–200 nm and had the composition of Fe106P50. Elemental chlorine was found in the surface of the particle especially prepared under argon plasma conditions. It was bonded with phosphorus and carbon in Fe-P particles prepared in argon plasma and mainly with carbon in Fe-P particles deposited under a hydrogen plasma. Formation of Fe-P improves the stability of phosphorus in air. Phosphorus enrichment in the surface of Fe-P particles was also found. The particles were characterized by TEM, SEM, infrared-spectroscopy, X-ray photoelectron spectroscopy quantitative analysis, differential scanning colorimetry, inductively coupled plasma, X-ray diffraction and X-ray microprobe analysis. The formation mechanism of Fe-P amorphous particles was also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349663
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  • 6
    Electronic Resource
    Electronic Resource
    Muon spin relaxation in CeCu2Si2 and muon knight shift in various heavy-fermion systems (1986)
    Springer
    Hyperfine interactions 31 (1986), S. 413-418 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Positive muon spin precession has been observed in various heavy-fermion systems in the transverse external magnetic field. In the superconductor CeCu2.1Si2, the relaxation rate of muon spins increases rapidly with decreasing temperature below TC. This is interpreted as the results of the inhomogeneous fields due to the imperfect penetration of the external field into the type-II superconducting state. The magnetic-field penetration depth λ is derived from the observed muon spin relaxation rate. λ is about 1200 ∢ at T∼0.5TC, and the temperature dependence of λ is consistent with the relation expected for a BCS superconductor. We have also measured the muon Knight shift Kμ in the normal (or paramagnetic) state of various heavy-fermion systems. Kμ is large and negative (about −1000∼−3000 ppm at T=10 K) for CeCu2Si2, UPt3 and CeAl3, while more complicated signals are measured in CePb3 and CeB6. The negative muon Knight shift in the non-magnetic heavy-fermion systems is discussed in terms of the Kondo-coupling between the conduction- and f-electrons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02401589
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  • 7
    Electronic Resource
    Electronic Resource
    The superconducting properties of YBa2(Cu1−xMx)3O7 for M=Zn and Ni (1991)
    Springer
    Hyperfine interactions 63 (1991), S. 81-86 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Transverse and zero-field μSR measurements were made on YBa2(Cu1−xNix)3O7−y withx=0.1 and 0.2, and YBa2(Cu1−x Zn x )3O7−y withx=0.03, 0.06, 0.1, and 0.16, wherey≈0.1. Since doping may lead to magnetic ordering this was searched for with both zero and transverse field μSR, but no evidence was found over the temperature range studied: 10–100 K. However, depolarization rates as functions of temperature were obtained, and the low temperature values of these are σ=3.2 μs−1.1.6μs−1, and 1 μs−1 forx=0.01, and 0.2 Ni, respectively, and σ=0.8 μs−1, 0.75 μs−1, 0.65 μs−1, and 0.4 μs−1 forx=0.03, 0.06, 0.1, and 0.16 Zn, respectively. Estimates for the effect of decreasing electron concentration for Zn are made, but these alone do not account for the drop in σ. Estimates for the effect of scattering on λ and hence σ are made. The reduction in σ for Ni dopant is in surprisingly good agreement with these estimates. For Zn the order of magnitude is correct, but the relative lack of further change in σ after the effect of the first 0.03 addition seems to imply a saturation of the effect of scattering.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02395988
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  • 8
    Electronic Resource
    Electronic Resource
    Magnetic ordering in Nd2-xCexCuO4-y (1991)
    Springer
    Hyperfine interactions 63 (1991), S. 305-309 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The n-type cuprate superconductor and closely related samples of the general form Nd2−x Ce x CuO4−y have been studied with the muon spin relaxation technique. Non-super-conducting samples display antiferromagnetism (AFM) withT N below 150 K, the value being dependent upon both Ce concentration and oxygen depletion. The results are interpreted in terms of carrier concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02396018
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  • 9
    Electronic Resource
    Electronic Resource
    Superconductivity and magnetic ordering in YBa2(Cu1−x Fe x )3O7 (1991)
    Springer
    Hyperfine interactions 63 (1991), S. 253-258 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Transverse-and zero-field μSR measurements have been made for YBa2(Cu1−x Fe x )3O7 withx=0.04, 0.08 and 0.12. The temperature range studied was from approximately 7.5 K to 100 K. The onset of magnetic ordering commences at about 7.5 K forx=0.04, 10 K forx=0.08 and 20 K forx=0.12. The Gaussian depolarization parameter, σ ofG x (t) = exp(−σ2 t 2/2), is depressed by a factor of about 0.6 forx=0.04, but for thex=0.08 sample σ is depressed by a factor of 10 and increasing suppression is seen as the temperature is lowered below 45 K. This decrease in σ is interpreted in terms of decreasing electronic mean free paths.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02396011
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  • 10
    Electronic Resource
    Electronic Resource
    Synthesis and physical properties of poly(fluoroalkylether)urethanes (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 41 (1990), S. 1777-1795 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polyurethane block copolymers were synthesized containing between 33 and 50 wt % hard segments based on 4,4'-diphenylmethane diissocyanate (MDI) and either 1,4-butanediol (BD), or N-methyldiethanolamine (MDEA) as the chain extender. The soft segments were composed of poly(tetramethylene oxide) (PTMO) and fluoropolyether glycol (FPEG) oligomers (Mn = 1000 and 1899, respectively), copolymerized to produce polyurethanes containing 5-100 wt % FPEG soft segment. The PTMO polyol in one sample was substituted with a tetrahydrofuran/ethylene oxide polyol (75 : 25 mole ratio) (Mn = 1140). The MDEA-extended polymer was ionized using 1,3-propane sultone. The bulk and surface properties of these polymers were evaluated by a variety of techniques. Differential scanning calorimetry (DSC) and dynamic mechanical analysis showed that the incorporation of 5-14 wt % FPEG into the soft segment had essentially no effect on the polymer's multiphase structure. The ultimate tensile strength and elongation was reduced by the addition of FPEG. Chain extending with BD as opposed to MDEA improved phase separation and the ultimate tensile strength. In vacuum, surface enrichment of the low surface energy FPEG was observed for all the polymers, using X-ray photoelectron spectroscopy (XPS). The dynamic contact angle results indicate that the polymer surfaces rearranged in an aqueous environment to minimize their interfacial free energy.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1990.070410734
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