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121.
The authors describe a scalable neural system, HyperNet, based on a probabilistic RAM-based architecture and using a custom VLSI IC. A system using five HyperNet VLSI ICs and capable of realising up to 10240 neurons has been designed, manufactured and demonstrated to have the potential to learn more than three orders of magnitude faster than simulations on current workstations 相似文献
122.
Gaidis M.C. Friedrich S. Segall K. Prober D.E. Szymkowiak A.E. Moseley S.H. 《Applied Superconductivity, IEEE Transactions on》1996,6(1):1-4
We report the development of Nb-Ta-Al-Al2O3-Al superconducting tunnel junction structures for high energy resolution and high efficiency X-ray detection. These devices utilize a Ta X-ray absorber with superconductor “bandgap engineered” quasiparticle trapping to improve charge collection. Experimental results at 0.3 K are presented, showing energy resolution of 102 eV full-width-half-maximum for 6 keV X-rays. Collected charge is in excess of 5×106 electrons. The absorption efficiency is better than 35%. Devices thermally cycle with no change in characteristics 相似文献
123.
The transverse resonance method is used for the accurate analysis of propagation structures with discontinuous substrate layers. The original aspect of the approach is the use of LSE-LSM modes as basis functions combined with appropriate trial functions which leads to small-size matrices and reduces the numerical effort. As an example the propagation characteristics of a microslab waveguide with finite metallisation thickness are calculated.<> 相似文献
124.
F. Rubio F. García H. D. Burrows A. A. C. C. Pais A. J. M. Valente M. J. Tapia J. M. García 《Journal of polymer science. Part A, Polymer chemistry》2007,45(9):1788-1799
The interaction between trivalent lanthanide ions and poly(1,4,7,10,13‐pentaoxacyclopentadecan‐2‐yl‐methyl methacrylate), PCR5, in aqueous solution and in the solid state have been studied. In aqueous solution, evidence of a weak interaction between the lanthanides and PCR5 comes from the small red shift of the Ce(III) emission spectra and the slight broadening of the Gd(III) EPR spectra. From the Tb(III) lifetimes in the presence of H2O and D2O the loss of one or two water coordinated molecules is confirmed when Tb(III) is bound to PCR5. An association constant of the order of 200 M?1 was obtained for a 1:1 (lanthanide:15‐crown‐5) complex from the shift of the polymer NMR signals induced by Tb(III). A similar association constant is obtained from the differences of the molar conductivity of Ce(III) solution at various concentrations in presence and absence of PCR5. When Tb(III) is adsorbed on PCR5 membranes, lifetime experiments in H2O and D2O confirm the loss of 5 or 6 water coordinated molecules indicating that in solid state the lanthanide(III)‐PCR5 interaction is stronger than in solution. The adsorption of Ce(III) in PCR5 membranes shows a Langmuir type isotherm, from which an equilibrium constant of 39 M?1 has been calculated. SEM shows that the membrane morphology is not much affected by lanthanide adsorption. Support for lanthanide ion–crown interactions comes from ab initio calculations on 15‐crown‐5/La(III) complex. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1788–1799, 2007 相似文献
125.
Five-terminal silicon-on-insulator (SOI) MOSFETs have been characterized to determine the threshold voltage at the front, back, and sidewall as a function of the body bias. The threshold voltage shift with the body bias at the front and back interfaces can be explained by the standard bulk body effect equation. However, the threshold voltage shift at the sidewall is smaller than predicted by this equation and saturates at large body biases. This anomalous behavior is explained by two-dimensional charge sharing between the sidewall and the front and back interfaces. An analytical model that accounts for this charge sharing by a simple trapezoidal approximation of the depletion regions and correctly predicts the sidewall threshold voltage shift and its saturation is discussed. The model makes it possible to measure the sidewall threshold even when it is larger than the front threshold voltage 相似文献
126.
Solutions are presented for the impulsively started uniformstream and simple shear flows past a point source of momentum,which can be interpreted to describe the position and the widthof the front which transmits the knowledge of the singularitythrough a slightly viscous fluid. These understandings are thengeneralized to show that the front always moves with velocityslower than that of a (strictly monotonic) convective velocity,and also that its width always grows faster than with simplediffusion. Finally, a remarkably simple, exact expression is given forvorticity due to a simple shear flow past a point vortex. 相似文献
127.
Q. Gong R. N tzel P.J. van Veldhoven T.J. Eijkemans J.H. Wolter 《Journal of Crystal Growth》2005,280(3-4):413-418
We report on the shape transition from InAs quantum dashes to quantum dots (QDs) on lattice-matched GaInAsP on InP(3 1 1)A substrates. InAs quantum dashes develop during chemical-beam epitaxy of 3.2 monolayers InAs, which transform into round InAs QDs by introducing a growth interruption without arsenic flux after InAs deposition. The shape transition is solely attributed to surface properties, i.e., increase of the surface energy and symmetry under arsenic deficient conditions. The round QD shape is maintained during subsequent GaInAsP overgrowth because the reversed shape transition from dot to dash is kinetically hindered by the decreased ad-atom diffusion under arsenic flux. 相似文献
128.
White J.R. White C.J. Slocum A.H. 《Microwave and Wireless Components Letters, IEEE》2005,15(11):793-795
The development and testing of a miniaturized, high-Q, broadly tunable resonator is described. An exemplary device, with a center frequency that is continuously tunable from 1.2 to 2.6GHz, was tested in detail. Experimental results demonstrated a resonator Q of up to 380, and typical insertion loss of -1.9dB for a 25MHz 3-dB bandwidth. These resonators have been used to stabilize a broadly-tunable oscillator with phase noise of -132dBc/Hz at 100-kHz offset, with a center frequency tunable from 1.2-2.6GHz, and a tuning speed of 1GHz/ms. 相似文献
129.
In the last decade, the Grid emerged from computing-intensive application domains. It has become very difficult to distinguish between "real" Grids, Web services, and simply a distributed computing environment. A critical discussion of Grid technologies points out the pros and cons of applying current Grid technologies in a business or enterprise environment. 相似文献
130.
The effect of hydrostatic pressure on the structure of a plastic columnar discotic triphenylene has been investigated. The goal was to determine whether pressure can be used to modify electronic properties via changes in structural properties of columnar discotics to any significant extent. The findings are that (i) the intra- and inter-columnar distances are reduced in a nearly isotropic fashion, (ii) that the crystal sizes are reduced and (iii) that a transition takes place from a more highly ordered plastic columnar to a less ordered hexagonal columnar state with increasing pressure. The induced decrease of the molecular distances, amounting to 6% for pressures up to 17 kbar, are clearly too small to induce an appreciable modification of the electronic structure and thus opto-electronic properties. 相似文献