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排序方式: 共有533条查询结果,搜索用时 15 毫秒
41.
G. P. Kopitsa S. V. Grigoriev V. V. Runov S. V. Maleyev V. M. Garamus A. G. Yashenkin 《JETP Letters》2005,81(11):556-560
In order to directly observe neutron scattering by heavy fermion quasiparticles at low temperatures, a CeRu2Si2 single crystal has been studied by the small-angle neutron scattering method. In the experiment, neutron scattering is observed at T = 0.85 K for momentum transfers q ≤ 0.04 Å?1, which is treated as the orbital component of magnetic scattering by heavy fermion quasiparticles. It has been found that the application of a magnetic field H = 1 T leads to both an increase in the observed scattering and its anisotropy with respect to the field direction. Moreover, measurements in the magnetic field reveal additional scattering for q > 0.04 Å?1, which is well described by a Lorentzian and is interpreted as neutron magnetic scattering by spin-density fluctuations with a correlation radius Rc ≈ 30 Å. 相似文献
42.
Grigorieva OV Kovalchuk NM Grigoriev DO Vollhardt D 《Journal of colloid and interface science》2003,261(2):490-497
Autooscillation of the surface tension is a phenomenon related to Marangoni instability periodically arising and fading by dissolution of a surfactant droplet under a water-air interface. A detailed experimental investigation was performed to clear up the influence of the system geometry on development and characteristics of autooscillations. It was found that the aspect ratio is an additional dimensionless parameter that determines the system behavior equally to the Marangoni number. The influence of the cell diameter, capillary immersion depth, and droplet radius on the autooscillation period and amplitude was studied as well. 相似文献
43.
D. Yu. Grigoriev 《Journal of Mathematical Sciences》2003,118(2):4963-4965
Earlier, D. Yu. Grigoriev and N. N. Vorob'yov obtained an upper bound
for the number of vectors of multiplicities for solutions of systems of the form
(assuming that the system has a finite number of solutions). In the system above,
are polynomials of degrees
. In the present paper, we show that the order of growth of this bound is close to the exact one. In particular, in the case d=n, the construction provides a doubly-exponential (in n) number of vectors of multiplicities. Bibliography: 4 titles. 相似文献
44.
J. Dorenbosch F. Udo J. V. Allaby U. Amaldi G. Barbiellini M. Baubillier F. Bergsma A. Capone W. Flegel F. Grancagnolo M. Jonker L. Lanceri M. Metcalf C. Nieuwenhuis J. Panman R. Plunkett C. Santoni K. Winter I. Abt F. W. Büsser H. Daumann P. D. Gall T. Hebbeker F. Niebergall P. Stähelin P. Gorbunov E. Grigoriev V. Kaftanov V. Khovansky A. Rosanov A. Baroncelli L. Barone B. Borgia C. Bosio M. Diemoz U. Dore F. Ferroni E. Longo L. Luminari P. Monacelli S. Morganti F. de Notaristefani L. Tortora V. Valente CHARM Collaboration 《Zeitschrift fur Physik C Particles and Fields》1989,41(4):567-589
A determination of sin2 θ w based on measurements of elastic scattering of muon-neutrinos and muon-anti-neutrinos on atomic electrons is described. These purely leptonic processes were studied using the CHARM calorimeter exposed to neutrino and antineutrino wide-band beams at the CERN super proton synchrotron. A total of 83±16 neutrino-electron and 112±21 antineutrino-electron events have been detected. From the measurement of the ratio of muon-neutrino and muon-antineutrino cross-sections a value of sin2 θ w =0.211±0.037 was obtained. 相似文献
45.
J Kr gel R Wü stneck F Husband P.J Wilde A.V Makievski D.O Grigoriev J.B Li 《Colloids and surfaces. B, Biointerfaces》1999,12(3-6):399-407
The adsorption isotherms, adsorption kinetics and surface rheological properties of β-lactoglobulin, β-casein, in the absence and presence of Tween 20 were measured. To study the adsorption process (isotherms and kinetics) at the water–air interface the pendant drop technique (axial drop shape analysis, ADSA), and ring tensiometry were used. The surface shear rheological parameters were measured with a torsion pendulum set-up. Also, data of the equilibrium film thickness and surface diffusion coefficients obtained from fluorescence recovery after photobleaching (FRAP) measurements are used to understand the competitive adsorption mechanism. The adsorption process and shear rheological behaviour of the studied systems show a rather complex behaviour which depends most of all on the system's composition. At high protein or surfactant content the behaviour is controlled by the main component while for the more mixed systems the adsorption process is complex and consists of partial adsorption, surfactant–protein interaction and protein rearrangement as a function of surface coverage. The results obtained illustrate that all these processes must be taken into account in future new theoretical models to be derived for such systems. 相似文献
46.
The relationship is established between the Fedosov deformation quantization of a general symplectic manifold and the BFV-BRST
quantization of constrained dynamical systems. The original symplectic manifold ℳ is presented as a second class constrained
surface in the fibre bundle ?*
ρℳ which is a certain modification of a usual cotangent bundle equipped with a natural symplectic structure. The second class
system is converted into the first class one by continuation of the constraints into the extended manifold, being a direct
sum of ?*
ρℳ and the tangent bundle Tℳ. This extended manifold is equipped with a nontrivial Poisson bracket which naturally involves two basic ingredients of
Fedosov geometry: the symplectic structure and the symplectic connection. The constructed first class constrained theory,
being equivalent to the original symplectic manifold,
is quantized through the BFV-BRST procedure. The existence theorem is proven for the quantum BRST charge and the quantum BRST
invariant observables. The adjoint action of the quantum BRST charge is identified with the Abelian Fedosov connection while
any observable, being proven to be a unique BRST invariant continuation for the values defined in the original symplectic
manifold, is identified with the Fedosov flat section of the Weyl bundle. The Fedosov fibrewise star multiplication is thus
recognized as a conventional product of the quantum BRST invariant observables.
Received: 28 April 2000 / Accepted: 6 December 2000 相似文献
47.
L. P. Avakyants P. Yu. Bokov A. T. Grigoriev A. V. Chervyakov 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(7):941-943
Semi-insulating GaAs(100) substrates subjected to ion plasma etching in different regimes have been investigated by photoreflectance
spectroscopy. The photoreflectance spectra of the processed samples exhibit Franz-Keldysh oscillations, which indicate a decrease
in the defect density in the surface region. On the basis of the experimental data and the results of simulation of the photoreflectance
spectra, optimal regimes of sample etching have been found. 相似文献
48.
49.
P. D. Grigoriev A. M. Dyugaev E. V. Lebedeva 《Journal of Experimental and Theoretical Physics》2008,106(2):316-325
The temperature dependence of electron mobility is examined. We calculate the contribution to the electron scattering rate
from the surface level atoms (SLAs), proposed in [10]. This contribution is substantial at low temperatures T < 0.5, when the He vapor concentration is exponentially small. We also study the effect of depopulation of the lowest energy
subband, which leads to an increase in the electron mobility at high temperature. The results explain certain long-standing
discrepancies between the existing theory and experiment on electron mobility on the surface of liquid helium.
The text was submitted by the authors in English. 相似文献
50.