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991.
V. I. Grafutin V. L. Grishkin G. G. Myasishcheva Yu. V. Funtikov Yu. A. Novikov 《Physics of the Solid State》1998,40(4):549-551
The empirical relation θ
p
6
/I
p=aK (where θ
p is the limiting angle of the parabolic component in the angular distributions of annihilation photons in metals, I
p is the integrated contribution of this component, K=1, 2, 3, ... is an integer, and a is a constant independent of the type of metal) observed earlier has been tested on magnesium, aluminum, copper, zinc, lead,
and bismuth samples. The validity of this relation has been substantiated. The value of the dimensionless constant a has been determined and was found to coincide within experimental error with the result obtained in previous measurements.
It is shown that the value of K for the same metal but for different samples may be different. It is conjectured that this may be due to different defect
concentrations in samples.
Fiz. Tverd. Tela (St. Petersburg) 40, 600–602 (April 1998) 相似文献
992.
993.
994.
The characteristics of unipolar and bipolar corona discharges in mixtures He/Ar/Kr, He/Ar/Xe, and He/Kr/Xe at atmosphere pressures
in electrode systems of the point-plane and point-grid type distributed along the length. It is shown that bipolar corona
discharges can be used in the preionization systems of high-pressure inert-gas-atom lasers. The spectral characteristics of
the plasma are investigated, and the dependence of the relative intensity of the radiation in the lines Ar(4s-4p), Kr(5s-5p), and Xe(6s-6p) on the composition and pressure of the working mixtures and on the value of the corona discharge current are determined.
Zh. Tekh. Fiz. 67, 15–18 (November 1997) 相似文献
995.
The plane contact problem of steady thermoelasticity taking heat generation into account 总被引:2,自引:0,他引:2
The plane steady contact problem of thermoelasticity when there is heat generation from friction, which arises when an infinite cylindrical punch moves over the surface of an elastic half-space along its generatrix, is considered. It is assumed that heat exchange between the free boundary of the half-space and the surrounding medium obeys Newton's law, while the condition for ideal thermal contact exists in the region in which the solids interact. The problem is reduced to a system of three integral equations in the heat fluxes and temperature. The effect of the thermal and mechanical properties of the cylinder and the half-space on the main contact characteristics is investigated numerically. 相似文献
996.
The specific heat C
total of crystalline and amorphous Eu2(MoO4)3 is measured in the temperature interval 4.5–30 K. The amorphous state is obtained by applying pressure ∼7 GPa at room temperature.
It is found that the specific heat of the crystal at T⩽7.5 K is described by a cubic function of temperature, while the specific
heat of the amorphous sample has a strongly non-Debye character in the entire experimental temperature interval. The curve
of C
total for amorphous europium molybdate is analyzed in a model of soft atomic potentials, and it is shown that it agrees well with
universal low-temperature anomalies of the specific heat of classical glasses obtained by quenching from the liquid.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 8, 623–627 (25 October 1998) 相似文献
997.
O. A. Dubovskii 《Physics of the Solid State》1998,40(11):1937-1941
Solutions of the dispersion equations for polariton states in finite one-dimensional crystals of arbitrary length are obtained.
The appearance and evolution of the radiative and nonradiative polariton branches are traced as the length varies from two
monomers to limiting values, above which the spectrum no longer undergoes significant changes. The dependences of the frequencies
and radiative widths on the polariton wave vector are found for various orientations of the dipole moment of the quantum transition.
The evolution of superradiance as the length of the crystal increases is traced. Some previously unknown significant features
of the polariton spectrum are noted particularly the damping of the branch traditionally termed nonradiative as a consequence
of emission from the end faces.
Fiz. Tverd. Tela (St. Petersburg) 40, 2136–2140 (November 1998) 相似文献
998.
O. M. Stanzhitskii 《Ukrainian Mathematical Journal》1998,50(2):355-359
We consider invariant sets of the form V(t, x) = 0, where V(t, x) is the Lyapunov function of the corresponding deterministic system.
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 50, No. 2, pp. 309–312, February, 1998.
This work was partially financially supported by the Ministry of Ukraine for Science and Technology. 相似文献
999.
V. B. Gorskii 《Computational Mathematics and Modeling》1997,8(1):29-30
The variational model and the Hamiltonian canonical equation of motion are updated using the Lagrangian invariant for three-dimensional
unsteady adiabatic flows of magnetizable, ideally conducting, compressible inviscid fluid. The results are applied to derive
Hamiltonian noncanonical equations of motion in physically defined variables.
Translated from Nelineinye Dinamicheskie Sistemy: Kachestvennyi Analiz i Upravlenie — Sbornik Trudov, No. 2, pp. 44–46, 1994. 相似文献
1000.
V. Ye. Zaichick 《Fresenius' Journal of Analytical Chemistry》1995,352(1-2):219-223
The contents of 21 chemical elements (Ag, Br, Ca, Cl, Co, Cr, Cs, Fe, Hg, K, Mg, Mn, Na, P, Rb, Sb, Sc, Se, Sr, Zn, Zr) in synthetic reference materials (SRMs) were compared with those in natural reference materials (NRMs) using short- and long-lived radionuclides. SRMs called synthetic standards (SSs) and synthetic standards, biological (SSBs) were prepared on the basis of phenol-formaldehyde resol resins in the Institute of Physics, Georgian Academy of Science. The NRMs included such IAEA reference materials as H-4 (animal muscle), A-13 (animal blood), H-5 (animal bone), SL-1 (lake sediment), SOIL-7 (soil), A-9 (mixed human diet), and IAEA-153 (milk powder). It was shown that SSB-SRMs possessed good representativity of the 30–50 mg tablets, high precision, operational convenience, and could be recommended for the INAA of a wide range of medico-biological and bioecological objects. 相似文献