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21.
22.
M. Yu. Artyushenko V. A. Voronko K. V. Gusak I. V. Zhuk M. G. Kadykov A. S. Potapenko A. A. Safronova V. V. Sotnikov S. I. Tyutyunnikov V. I. Furman V. V. Chilap A. V. Chinenov 《Physics of Particles and Nuclei Letters》2013,10(6):544-548
The results of measurements of the beam parameters on the target upon irradiation of the QUINTA subcritical uranium assembly with deuterons with energies of 1, 4, and 8 GeV are presented. Data on the position of the incident particle beam relative to the assembly axis and on the actual geometric parameters of the beam make it possible to analyze information on the spatial distributions of reaction rates within the target assembly correctly, comparing such distributions obtained at different irradiation sessions and modeling the experiments with the use of MCNPX, GEANT4, FLUKA, and other similar software tools. 相似文献
23.
A. G. Sotnikov 《Optics and Spectroscopy》2011,111(4):639-646
We study theoretically the linear response of a gas in the state with Bose-Einstein condensate to the perturbation by an external
electromagnetic field (weak laser pulse). The Green’s functions formalism is used to study the dispersion characteristics
of a system at finite temperatures. It is shown that the group velocity of the near-resonant pulses in condensate in some
cases can strongly depend on the temperature. Basing on the account of the Zeeman splitting of the magnetic states we study
also a possibility to filter light pulses by the condensate with several occupied quantum states. 相似文献
24.
E. P. Smirnova A. Sotnikov S. Ktitorov N. Zaitseva H. Schmidt M. Weihnacht 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,83(1):39-45
The longitudinal acoustic wave velocity and attenuation in
BiFeO3 ceramics have been measured by ultrasonic
pulse-echo technique at a frequency of 10 MHz in the temperature range from
4.2 K to 830 K. The anomalies observed in the sound velocity and attenuation
behavior versus temperature are attributed to the assumed relaxation in the
temperature range 200–500 K and antiferromagnetic phase transition at
higher temperatures. Order parameter fluctuations along with
magnetostriction are discussed as the factors determining the acoustic wave
velocity anomaly in the vicinity of the antiferromagnetic phase transition
point. 相似文献
25.
26.
A.?V.?Sotnikov R.?Kunze H.?Schmidt M.?Weihnacht M.?Hengst J.?G?tze 《Physics of the Solid State》2009,51(2):275-279
The elastic, piezoelectric, and dielectric constants of new piezoelectric single crystals Sr3NbGa3Si2O14 (SNGS) are measured. The elastic moduli C
11 and C
66 and the piezoelectric coefficient e
11 are determined over a wide temperature range. It is demonstrated that the piezoelectric activity of the crystal is retained
up to the highest temperatures (900°C). 相似文献
27.
V. V. Lemanov A. V. Sotnikov E. P. Smirnova M. Weihnacht 《Physics of the Solid State》2002,44(11):2039-2049
Ceramic samples of (1−x)SrTiO3-xSrMg1/3Nb2/3O3 and (1−x)SrTiO3-xSrSc1/2Ta1/2O3 were prepared, and their dielectric properties were studied at x=0.005–0.15 and 0.01–0.1, respectively, at frequencies 10 Hz–1 MHz and at temperatures 4.2–350 K. A giant dielectric relaxation
was observed in the temperature range 150–300 K, and not so strong but well-developed relaxation was found in the temperature
range 20–90 K. The activation energy U and the relaxation time τ0 were determined to be 0.21–0.3 eV and from 10−11 to 10−12 s for the high-temperature relaxation and 0.01–0.02 eV and 10−8–10−10 s for the low-temperature relaxation, respectively. The additional local charge compensation of the heterovalent impurities
Mg2+ and Nb5+ (or Sc3+ and Ta5+) by free charge carriers or the host ion vacancies is suggested to be the underlying physical mechanism of the relaxation
phenomena. On the basis of this mechanism, the Maxwell-Wagner model and the model of reorienting dipole centers Mg2+ (or Sc3+) associated with the oxygen vacancy are proposed to explain the high-temperature relaxation with some arguments in favor
of the latter model. The polaron-like model with the Nb5+-Ti3+ center is suggested as the origin of the low-temperature relaxation. The reasons for the absence of ferroelectric phase transitions
in the solid solutions under study are also discussed.
From Fizika Tverdogo Tela, Vol. 44, No. 11, 2002, pp. 1948–1957.
Original English Text Copyright ? 2002 by Lemanov, Sotnikov, Smirnova, Weihnacht.
This article was submitted by the authors in English. 相似文献
28.
A gas-chromatographic procedure for the determination of 1,1-dimethylhydrazine in water was developed on the basis of its reaction with 4-nitrobenzaldehyde yielding the corresponding hydrazone, the extraction of the latter from water with an organic solvent, its subsequent preconcentration by evaporation, and the determination on a gas chromatograph with a nitrogen-phosphorus detector. The determination limit of 1,1-dimethylhydrazine is 0.03 μg/L. The relative error of the determination is no larger than 22% in the concentration range 0.06–0.60 μg/L and 33% at a level of 0.03 μg/L. 相似文献
29.
I. S. Afonkin A. M. Sotnikov R. R. Gataullin L. V. Spirikhin I. B. Abdrakhmanov 《Russian Journal of Organic Chemistry》2004,40(12):1764-1768
Isomerization of 2-allyl-6-methylaniline by the action of potassium hydroxide at 300°C afforded cis and trans isomers of 2-methyl-6-(1-propenyl)aniline which were converted into the corresponding carbamates by treatment with ethyl chloroformate. Ethyl 2-methyl-6-(1-propenyl)phenylcarbamates reacted with bromine to give mixtures of 4-(1-bromoethyl)-8-methyl-1,4-dihydro-2H-3,1-benzoxazin-2-one and ethyl 2- methyl-6-(1,2-dibromopropyl)phenylcarbamates. Treatment of the same compounds with N-bromosuccinimide resulted in formation of 2-ethoxy-4H-3,1-benzoxazine derivatives. The reaction of N-{6-methyl-2-[(Z)- 1-propenyl]-phenyl}methanesulfonamide gave a mixture of stereoisomeric N-[6-methyl-2- (1,2-dibromopropyl)-phenyl]-methanesulfonamides.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 12, 2004, pp. 1815–1818.Original Russian Text Copyright © 2004 by Afonkin, Sotnikov, Gataullin, Spirikhin, Abdrakhmanov.For communication V, see [1]. 相似文献
30.
Energy relaxation of the hot electron population generated by relativistic laser pulses in overdense plasma is analyzed for densities ranging from below to 1000 times solid density. It is predicted that longitudinal beam-plasma instabilities, which dominate energy transfer between hot electrons and plasma at lower densities, are suppressed by collisions beyond solid density. The respective roles of collisional energy transfer modes, i.e., direct collisions, diffusion, and resistive return current heating, are identified with respect to plasma density. The transition between the kinetic and the collisional regimes and scalings of collisional process are demonstrated by a fully integrated one-dimensional collisional particle simulation. 相似文献