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81.
The present work is devoted to the analysis of the functional form of the repulsive potential in the framework of soft-sphere model. We used two different approaches which were based on the treatment of an equation of state and spectra of molecular light scattering at large shifts of frequencies. In particular, it has been shown that the density dependence of pressure at P>103 MPa allowed to calculate the steepness exponent of the repulsive potential as a fitting parameter of the equation of state which possesses reliable extrapolation properties under extrapolating experimental PVT data in the high-pressure region. Processing of experimental data on a base of the statistical equation of state reveals the temperature dependence of the steepness parameter. The similar situation is also typical for the light scattering spectra. So for argon the value of this parameter varies from 15 to 10 in the gas phase and up to 24–28 in the liquid phase. The results obtained with the help of the equation of state and molecular light scattering spectra correlate well. 相似文献
82.
Motion of an isolated domain wall in two-layer uniaxial magnetic films with the same gyromagnetic ratios in the layers is
investigated by solving the Slonczewski equations using a numerical method. The steady-state motion regimes are established
for the domain with the angle of magnetization vector departure from the wall plane exceeding π.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 76–82, April, 2007. 相似文献
83.
Darshan C Kundaliya Reeta Vij AA Tulapurkar U Vaidya R Pinto RG Kulkarni 《Pramana》2002,58(5-6):1041-1044
Electrical resistance (R) measurements of a bulk La0.33Nd0.33Ca0.33MnO3 perovskite in magnetic fields up to 40 kOe have revealed anomalous temperature hysteretic effects both in 0 Oe and 20 kOe
magnetic fields. The sharp peak observed in the R vs. T plot indicates the occurrence of metal-to-insulator (M-I) transition at a temperature of T
MI=110 K and 140 K, for cooling and warming paths, respectively. An applied magnetic field of 20 kOe reduces the resistance
and shifts T
MI to 160 K and 185 K for cooling and warming, respectively. We have observed a much higher resistance in the cooling path than
in the warming path leading to the hysteretic resistance ratio (R
cool/R
warm) of 200 at 110 K and 1.8 at 160 K for 0 Oe and 20 kOe, respectively. Record values of colossal magnetoresistance (CMR) have
been achieved. The CMR value reaches nearly 99% in the temperature ranges of 90 K to 140 K and 90 K to 170 K for 20 kOe and
40 kOe magnetic fields in the cooling mode, respectively. The observed unusual behavior is attributed to the co-existence
of La-rich and Nd-rich domains assumed to be distributed randomly in the compound. 相似文献
84.
We have studied the peak effect (PE) phenomenon in single crystals of weakly pinned superconductors CeRu2 and 2H-NbS2. 2H-NbS2 is iso-structural and iso-electronic to 2H-NbSe2, whose similarity with CeRu2 as regards the PE representing the order-to-disorder transformation of the flux line lattice was claimed some time ago. We
report on the step change in equilibrium magnetization across the peak effect in CeRu2. We also present the vortex phase diagram of 2H-NbS2 obtained from the magnetization data, and compare the PE phenomenon in 2H-NbS2 and 2H-NbSe2. 相似文献
85.
I. A. Znamenskaya D. A. Nersesyan N. N. Sysoev E. Yu. Koroteeva Ya. N. Shirshov 《Moscow University Physics Bulletin》2016,71(4):405-412
This paper considers the results of an optical study of high-speed fluid jets ejected from a nozzle at 400 MPa. The objective was to study two-phase flows under extreme conditions and to analyze the possibility of the optimization of the device design. The process of a high-speed water jet as it exits the focusing tube of the Flow WaterJet Mach3 abrasive cutting machine, along with its development, and the state of the stationary flow are considered. The shadow method was used to investigate the initial stage of high-speed water-jet formation, as well as the jet-head dynamics during the first 200–400 µs after ejection at 400 MPa. A Photron FASTCAM SA5 high-speed camera with a frame rate of one million shots per second and an exposure time of 1 [mu]s and a FLIR SC7000 infrared thermal camera with a frame rate of 400 shot/s and an exposure time of 1 ms were employed in order to study the jet-formation process. The spatiotemporal characteristics of the jet-development process were analyzed. The jet velocity and the starting jet head acceleration were measured by post-processing of digital images. 相似文献
86.
Zherikova K. V. Makarenko A. M. Karakovskaya K. I. Zelenina L. N. Sysoev S. V. Vikulova E. S. Morozova N. B. 《Russian Journal of General Chemistry》2021,91(10):1990-1998
Russian Journal of General Chemistry - Experimental data on the saturated vapor pressure and melting of dicarbonyl(hexafluoroacetylacetonato)iridium [Ir(CO)2(hfac)] were obtained. Thermodynamic... 相似文献
87.
Monotonic (isotonic) regression is a powerful tool used for solving a wide range of important applied problems. One of its features, which poses a limitation on its use in some areas, is that it produces a piecewise constant fitted response. For smoothing the fitted response, we introduce a regularization term in the monotonic regression, formulated as a least distance problem with monotonicity constraints. The resulting smoothed monotonic regression is a convex quadratic optimization problem. We focus on the case, where the set of observations is completely (linearly) ordered. Our smoothed pool-adjacent-violators algorithm is designed for solving the regularized problem. It belongs to the class of dual active-set algorithms. We prove that it converges to the optimal solution in a finite number of iterations that does not exceed the problem size. One of its advantages is that the active set is progressively enlarging by including one or, typically, more constraints per iteration. This resulted in solving large-scale test problems in a few iterations, whereas the size of that problems was prohibitively too large for the conventional quadratic optimization solvers. Although the complexity of our algorithm grows quadratically with the problem size, we found its running time to grow almost linearly in our computational experiments. 相似文献
88.
Spectral and luminescence properties of gadolinium gallium garnet epitaxial films doped with terbium
N. V. Vasil’eva V. V. Randoshkin V. N. Kolobanov E. B. Kryukova V. V. Mikhaĭlin N. N. Petrovnin V. G. Plotnichenko Yu. N. Pyrkov D. A. Spasskiĭ N. N. Sysoev 《Physics of the Solid State》2007,49(3):478-483
Gadolinium gallium garnet single-crystal films containing terbium are grown through liquid-phase epitaxy from a supercooled solution melt in the PbO-B2O3 system. The optical absorption spectra in the wavelength range 0.2–10.0 μm and the luminescence spectra excited by synchrotron radiation with energies in the range 3.5–30.0 eV are investigated at temperatures of 10 and 300 K. It is revealed that the optical absorption spectra contain an absorption band with the maximum at a wavelength λ ≈0.260 μm, which corresponds to the spin-allowed electric dipole transition between the electronic configurations 4f 8(7 F 6) → 4f 7(8 S)5d of the Tb3+ ions. The narrow low-intensity absorption bands attributed to the 4f → 4f transitions from the 7 F 6 ground level to the 7 F 0–5 multiplet levels of the Tb3+ ions are observed in the wavelength range 1.7–10.0 μm. In the luminescence spectra measured at a temperature of 10 K, the highest intensity is observed for a band with the maximum at a wavelength λ ≈ 0.544 μm, which is associated with the 5 D 4 → 7 F 5 radiative transition in the Tb3+ ion. 相似文献
89.
T. N. Kudryavtseva P. I. Sysoev S. V. Popkov G. V. Nazarov L. G. Klimova 《Russian Chemical Bulletin》2015,64(6):1341-1344
Novel acridone derivatives bearing 1,3,4-moiety were synthesized by intramolecular cyclization of N´-[2-(9-oxoacridin-10(9H)-yl)acetyl]arylhydrazides. Study of antimicrobial activity of the synthesized compounds reveals that some of them are more active than the comparator drug rivanol. 相似文献
90.
Dynamics of regular polygonal shock waves (SWs), generated at thin wire explosion, with a closed surface front and numbers of sides n = 3, 4, 5, 6, 8, 10, 12, and 16 in the plane of polygons is experimentally studied. Depending on the initial Mach number M PSW0 of such waves and the number n, two convergence modes are implemented: convergence with and without changes in the number of sides n. It is shown that the shape of the reflected wave front differs from the shape of the converging SW front for polygonal SWs with n ≥ 8, i.e., it becomes smooth. The number M PSW0 is determined depending on initial characteristics of an SW generator and gas. A significant amplification of such SWs with n ≥ 12 is observed near to the center of polygons; their maximum amplification is estimated. 相似文献