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961.
A new architecture for the Van Atta self-steering array is presented. Active antenna techniques are used to realise a compact self-steering array with enhanced retrodirective properties. The experimental performance of the array is demonstrated and a technique is described which compensates for the beam pointing error induced by antenna array element directivity 相似文献
962.
Zhongde Wang Jullien G.A. Miller W.C. Jinghong Wang Bizzan S.S. 《Solid-State Circuits, IEEE Journal of》1997,32(2):206-214
Using an enhanced multiple output domino logic (EMODL) implementation of a carry lookahead adder (CLA), sums of several consecutive bits can be built in one nFET tree with a single carry-in. Based on this result, a new sparse carry chain architecture is proposed for the CLA adder. We demonstrate the design approach using a 32-b adder, and show that only four carries are sufficient for generating all sums, with a consequent reduction in the number of stage delays. Using a 1.2-μm CMOS technology, we verify our simulation procedures by fabrication and measurement of a 2.7 ns critical path 相似文献
963.
Bufferless distributed circuit (BDC) broadcasting is proposed as a technique for broadcasting high-speed chip input signals to a series of on-chip destination cells as needed in crosspoint switch, parallel multiplier, distributed amplifier, etc., chip designs. In contrast with conventional techniques that use an on-chip buffer to assist broadcasting, BDC broadcasting offers the advantage of lower signal delay and power dissipation. In an experimental GaAs heterojunction bipolar transistor (HBT) 8×4 crosspoint switch assembly, BDC broadcasting was found to achieve a 40% power savings with little or no penalty in jitter or bit error rate performance at a 10-Gb/s data rate 相似文献
964.
Auluck S.K.H. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1997,25(1):37-41
The validity of the snowplow model of plasma sheath propagation in a plasma focus (PF) and the localization of the magnetic field in the low density region behind the dense plasma sheath are two well-established experimental facts. It is shown that, when taken together, these two imply a deficiency in the momentum balance. The hypothesis that the current-carrying plasma layer is rotating while the dense plasma layer is not rotating is shown not only to resolve this momentum balance anomaly (MBA), but also to explain many observed phenomena in a unified manner 相似文献
965.
The relativistic four-quark equations are found in the framework of the dispersion relation technique. The behaviour of the low-energy four-particle amplitude is determined by its leading singularities in the pair invariant masses. The approximate solutions of these equations using the method based on the extraction of leading singularities of the amplitudes are obtained. The mass values of lowest exotic mesons are calculated. 相似文献
966.
It is shown that the potential perturbation that shifts a chosen standing wave in space is a block of potential barrier and well for every wave bump between neighbouring knots. The algorithms shifting the range of the primary localization of a chosen bound state in a potential well of finite width are as well applicable to the scattering functions if states of the continuous spectrum are considered as bound states normalized to unity but distributed on an infinite interval with vanishing density. The potential perturbations of the same type on the half-axis concentrate the scattering wave at the origin, thus creating a bound state embedded into the continuous spectrum (zero width resonance). 相似文献
967.
New effects are observed wherein the internal structure of the domain walls in a thin magnetic iron garnet film are modified
by the action of focused laser radiation. A single laser pulse with increasing power gives rise to the following: 1) displacement
of vertical Bloch lines in a domain wall; 2) generation of a pair of vertical Bloch lines on initially line-free walls; and,
3) an irreversible change in shape of a domain wall and the domain structure as a whole. The mechanism leading to the generation
and displacement of Bloch lines is connected with the motion of domain walls which is induced by a local change in the distribution
of demagnetizing fields as a result of a heating-induced decrease of the magnetization in the focal spot of the laser radiation.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 6, 398–402 (25 September 1997) 相似文献
968.
Changes in thin zinc-sulfide films under the action of the γ-radiation of Co60 are studied by investigating electroluminescence spectra of terbium embedded in these films as a luminescent probe. It is
shown that changes in the relation of the intensities of bands, a decrease in their halfwidth and the background component,
and simplification of the spectrum are observed in a short-wave region of the Tb radiation spectrum that corresponds to5D3→7Fj transitions. The same modification of the radiation spectrum is characteristic of ZnS films whose crystalline structure is
ordered in the course of thermal annealing at a temperature of 350°C. Based on the analysis of the data obtained it is inferred
that irradiating the ZnS films with small radiation doses of 104–105 rad leads to the ordering of their crystalline structure due to the elimination of one of the types of structural defects.
Institute of Physics of Semiconductors, National Academy of Sciences of Ukraine, 45, Nauka Ave., Kiev-28, 252650. Translated
from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 3, pp. 338–341, May–June, 1997. 相似文献
969.
S. Ya. Kotkovskii 《JETP Letters》1997,65(10):768-772
The probability of inclusive semileptonic decay of B mesons is calculated in the constituent-quark model. A compact formula is obtained for the differential decay width of a
B meson in terms of the corresponding decay width of a free b quark and the wave function of the internal motion of the quarks in the B meson. Numerical values of semileptonic-decay widths are obtained for a series of models of the wave function.
Pis’ma Zh. éksp. Teor. Fiz. 65, No. 10, 734–737 (25 May 1997) 相似文献
970.