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91.
A learning algorithm for multilayer neural networks based on biologically plausible mechanisms is studied. Motivated by findings in experimental neurobiology, we consider synaptic averaging in the induction of plasticity changes, which happen on a slower time scale than firing dynamics. This mechanism is shown to enable learning of the exclusive-OR (XOR) problem without the aid of error backpropagation, as well as to increase robustness of learning in the presence of noise. 相似文献
92.
U. Schwingenschlögl C. Schuster 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,55(1):43-47
The incommensurate composite systems M14Cu24O41 (M = Ca, Sr, La)
are based on two fundamental structural units: CuO2 chains and
Cu2O3 ladders. We present electronic structure calculations
within density functional theory in order to address the interrelations
between chains and ladders. The calculations account for the
details of the crystal structure by means of a unit cell comprising 10
chain and 7 ladder units. It turns out that chains and ladders can be treated
independently, which allows us to introduce a model system based on a
reduced unit cell. For the CuO2 chains, we find two characteristic
bands at the Fermi energy. Tight binding fits yield
nearest and next-nearest neighbour interactions of the same order of
magnitude. 相似文献
93.
U. Schwingenschlögl C. Schuster 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,60(4):409-411
By means of band structure calculations within the density functional
theory and the generalized gradient approximation, we investigate the
electronic structure of self-organized Pt nanowires on the Ge(001) surface.
In particular, we deal with a novel one-dimensional surface state confined
in the nanowire array and clarify its origin. Due to large Pt contributions,
the novel state is rather a mixed Ge–Pt hybrid state than a confined Ge
surface state. Moreover, we compare our results to data from scanning
tunneling microscopy. 相似文献
94.
95.
B.-E. Schuster A. Haug M. Häffner M. M. Blideran M. Fleischer H. Peisert D. P. Kern T. Chassé 《Analytical and bioanalytical chemistry》2009,393(8):1899-1905
We present a spectroscopic and microscopic characterization of the chemical composition, structure, and morphology of two
commercial negative resists using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS),
and atomic force microscopy (AFM). For this purpose, films of a novolak-based resist (ma-N 2400) and hydrogen silsesquioxane
(HSQ) are treated under different conditions (temperature, deep ultraviolet (DUV) exposure, CHF3 plasma). Topographic AFM images show that both heating and DUV exposure strongly affect the surface morphology of as-prepared
ma-N 2400 resist films. These different treatment conditions also lead to decreasing roughnesses, which indicates structural
reorganization. Furthermore, the decrease of the photoactive compound (bisazide) in the ma-N 2400 resist films, observed in
FTIR spectra, suggests cross-linking of the resist after CHF3 plasma treatment, heating, or DUV exposure. XPS measurements on different CHF3 plasma-treated surfaces reveal that a structurally homogeneous fluorine-containing polymer is generated that is responsible
for an enhanced etch resistance. FTIR measurements of HSQ films show a correlation between the degree of HSQ cross-linking
and baking time. 相似文献
96.
The subject of the work presented is a novel fiber-optic bio-sensor suitable for miniaturized systems. The sensor concept employs a long periodic fiber Bragg-grating (LPG) for the excitation of surface-plasmon waves (SPW) sensitive to molecular binding processes on the sensor surface. Here we present the principle of operation as well as modeling results concerning the operating wavelength and its influence on sensor sensitivity and LPG parameters. 相似文献
97.
Michael Schwarzer M. Schuster Roger von Hentig 《Analytical and bioanalytical chemistry》2000,368(2-3):240-243
? Palladium in gasoline was determined by means of neutron activation analysis (NAA) and selective sorbent extraction. Unleaded gasoline consistent with DIN EN 228, RON 95 was irradiated at a thermal neutron flux of Φth = 1.68 · 1013s–1cm–2 and an epithermal neutron flux of 3.32 · 1011s–1cm–2 for tirr = 12 h. The irradiated gasoline was digested with nitric acid and palladium was then separated as N,N-diethyl-N’-benzoylthiourea complex by an automated column pre-concentration procedure. The eluate of 50 μL was dried on a filter paper and the 88.03 keV photons resulting from the decay of 109Pd were detected in a low level HPGe spectrometer with an efficiency of 35.5%. Severe interferences with other matrix constituents, especially 82Br could be overcome and the detection limit for palladium was improved to 3.4 ng/L at a confidence level of 90%. Although the analytical procedure applied yielded the lowest detection limit for palladium obtained in gasoline up to now, no indications for the presence of palladium were found. 相似文献
98.
P. Vest M. Schuster und K. -H. König 《Fresenius' Journal of Analytical Chemistry》1989,335(7):759-763
Summary Benzoylthioureas are excellent reagents for solvent extraction and have a high selectivity for platinum-group metals. Very effective separations of platinum-group metals are possible due to control of the extraction parameters and variation of the ligand structure. An easy synthesis and a high chemical resistence allow technical applications.
Herrn Prof. Dr. G. Tölg zum 60. Geburtstag gewidmet 相似文献
Herrn Prof. Dr. G. Tölg zum 60. Geburtstag gewidmet 相似文献
99.
A generalization of Wegschcider's condition concerning equilibrium constants in chemically reacting systems is formulated, which is then proved to be a necessary and sufficient condition for detailed balancing. In order to include a large multitude of rate laws, a generalized mass action kinetics is considered which comprises usual mass action kinetics and all reversible enzyme kinetics and which is consistent with basic postulates of irreversible thermodynamics for ideal mixtures. Reaction systems of arbitrary stoichiometry are considered. They may contain reactants with fixed concentrations, as is characteristic for models of biochemical reaction networks. Existence, uniqueness, and global asymptotic stability of equilibrium states for reaction systems endowed with generalized man action kinetics are proved. Using these results, he generalized Wegscheider condition is shown to be a sufficient criterion for the applicability of the quasi-steady-state approximation. 相似文献
100.