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991.
992.
In this paper, space adaptivity is introduced to control the error in the numerical solution of hyperbolic systems of conservation laws. The reference numerical scheme is a new version of the discontinuous Galerkin method, which uses an implicit diffusive term in the direction of the streamlines, for stability purposes. The decision whether to refine or to unrefine the grid in a certain location is taken according to the magnitude of wavelet coefficients, which are indicators of local smoothness of the numerical solution. Numerical solutions of the nonlinear Euler equations illustrate the efficiency of the method. 相似文献
993.
A. L. Goldenberg V. N. Manuilov M. Yu. Glyavin 《Radiophysics and Quantum Electronics》2005,48(6):461-465
We describe a nonadiabatic electron gun operated in the mode of a currentconfined by spatial charge and intended for producing
helical electron beams for high-power gyroresonantdevices.Results of numerical simulation of electron trajectories and electron-beam
parameters arepresented. It is shown that for a high operating current, the pitch factor and the electronvelocity spread can
be significantly better than in the conventional adiabatic systems.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48,No. 6, pp. 517–522, June 2005 相似文献
994.
The ferromagnetic shape memory alloy with nominal composition Ni54Fe19Ga27 is investigated by Ac susceptibility and resistivity measurements. The alloy shows long-range ferromagnetic order below 290 K. The anomaly due to the martensitic transition is observed in the susceptibility and resistivity data in the temperature range around 220 K, which is associated with clear thermal hysteresis. Minor hysteresis loop technique was used to investigate the phase coexistence across the martensitic transition, and our analysis indicate that both martensite and austenite phases mutually coexist in the region of hysteresis. 相似文献
995.
The capability of a modern interpretation system for IR spectra has been tested, in which the process of structural assignment
is modelled by methods of fuzzy logic. Figures of merit were generated for different interpretation algorithms. These figures
of merit permit the validation as well as a comparison of independent interpretation systems. The influence of the sample
preparation practice onto the information content of the resulting spectrum has been evaluated as well. Automatically generated
band tables show only restricted reliability.
Received: 13 February 1997 / Revised: 1 April 1997 / Accepted: 3 April 1997 相似文献
996.
K. S. Birdi 《Colloid and polymer science》1997,275(6):561-566
The surface tension versus temperature data of homologous series of n-alkanes and n-alkenes is analyzed. Critical temperatures are shown to be predicted from these data, with a very high precision, after some
corrections are made. The corrections are shown to arise from the effect of the critical pressure on the extrapolated data
to surface tension approaching zero.
Received: 29 October 1996 Accepted: 13 December 1996 相似文献
997.
S. M. Dunaevskii A. L. Malyshev V. A. Trunov V. V. Popov 《Physics of the Solid State》1997,39(10):1636-1637
The results of investigating the temperature dependence of the resistivity, the differential magnetic susceptibility, and
the magnetoresistance of a partially substituted perovskite Sm1−x
SrxMnO3 (x=0.16–0.4) are presented. Colossal intrinsic magnetoresistance, reaching 90% in an external magnetic field of 30 kOe, is discovered
in the compound with x=0.30 at 77 K.
Fiz. Tverd. Tela (St. Petersburg) 39, 1831–1832 (October 1997) 相似文献
998.
S. Gukov 《JETP Letters》1997,65(8):694-700
The manifestly supersymmetric four-dimensional Wess-Zumino model with quenched disorder is considered at the one-loop level.
The infrared fixed points of a beta function form the moduli space ℳ=RP
2, where two types of phases are found: with and without replica symmetry. While the former phase possesses only a trivial
fixed point, this point become unstable in the latter phase, which may be interpreted as a spin glass phase.
Pis’ma Zh. éksp. Teor. Fiz. 65, No. 8, 657–662 (25 April 1997)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
999.
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
1000.
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