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971.
Morozov N. F. Indeitsev D. A. Muratikov K. L. Semenov B. N. Vavilov D. S. Kudryavtsev A. A. 《Doklady Physics》2021,66(9):269-272
Doklady Physics - In the present article it is shown that the presence of defects in a material for a certain duration of heat exposure leads to the necessity of taking into account the dependence... 相似文献
972.
Andreeva Olga V. Garifullin Bulat F. Zarubaev Vladimir V. Slita Alexander V. Yesaulkova Iana L. Saifina Liliya F. Shulaeva Marina M. Belenok Maya G. Semenov Vyacheslav E. Kataev Vladimir E. 《Molecular diversity》2021,25(1):473-490
Molecular Diversity - Based on the fact that a search for influenza antivirals among nucleoside analogues has drawn very little attention of chemists, the present study reports the synthesis of a... 相似文献
973.
This article is devoted to Control system with the Hysteresis Nonlinearities. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
974.
N. B. Chernysheva A. A. Bogolyubov V. V. Semenov 《Chemistry of Heterocyclic Compounds》1999,35(2):216-224
The reaction of 5-methylene-1,3-dioxolan-2-ones with aromatic or aliphatic amines as well as with the sodium salts of amino acids leads to 4-hydroxy-2-oxazolidinones. The reaction conditions depend on the basicity of the amines. The use of o-phenylenediamine in this reaction leads to the formation of a new heterocyclic system.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow; Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 241–251, February, 1999. 相似文献
975.
A. D. Semenov 《Journal of Experimental and Theoretical Physics》1999,89(3):552-558
This paper reports on an investigation of transient photoimpedance response to radiation, in other words, real-time variations
of the impedance induced by femtosecond optical pulses in superconducting films transferred to the mixed state by an external
magnetic field applied parallel to the c-axis. When the films were in a state characterized by the absence of dc resistivity, the response amplitude increased with the magnetic field faster than expected owing to the contribution of magnetic
vortices to the impedance of a superconductor with s-wave pairing of electrons. It turned out that the effect is due to a growth in the effective density of quasiparticle states
in the mixed state of a d-wave superconductor. In the absence of magnetic field, however, the response amplitude was higher at lower temperatures,
which contradicts the predictions of both models. Possible reasons for this feature in the response as a function of temperature
are discussed.
Zh. éksp. Teor. Fiz. 116, 1035–1047 (September 1999) 相似文献
976.
Evgeny N. Pestov Alla N. Besedina Dmitry E. Pestov Vladimir V. Semenov 《Applied magnetic resonance》2020,51(2):195-204
One of the most important problems in achieving daily frequency instability $$\sigma _{y} < 5 \cdot 10^{{ - 14}}$$ of on-board rubidium atomic clocks on absorption cell with working 87Rb atoms and mixture of buffer gases is realization of the TFS parameter — of temperature frequency shift $$\delta \nu \left( T \right)$$ at the level of $$\ \le 3 \cdot 10^{{ - 12}} /\, {^\circ } {\text{C}}.$$ The temperature dependence of the microwave “0–0” transition frequency $$\nu \left( T \right)$$ has an extremum with a small flat top ∆T ~ 0.5 °C to which the 87Rb-cell operating temperature is tuned. Significant difficulties arise in maintaining the high stability of this small ∆T zone under conditions of increased 87Rb cell operating temperature, $$T>70\, ^\circ{\rm C}$$, with an accuracy of < 0.005 °C for a day or more. To solve this problem, authors proposed a new type of 87Rb absorption cell with two dissimilar anti-relaxation (AR) components (wall coating + buffer gas, 40Ar) and created a special physical setup for optical spin pumping of 87Rb atoms at the microwave magnetic resonance frequency, $$\nu \sim \;6.834\,\;{\text{GHz}}$$, with a resolution $$0.01 \,\mathrm{H}\mathrm{z}$$. Investigations have shown TFS $$\sim 1.4 \cdot 10^{{ - 12}} /\;{{^\circ }} {\text{C}}$$ in significantly expanded (by an order of magnitude) zone, $$\Delta T$$ ≃ $$5 \left(\pm 1\right)\,\, ^\circ{\rm C} ,$$ in the operating temperature range of $$\left( {35 \div 41} \right)\;^{ \circ } {\text{C}},$$ which is ensured inside a satellite, for example. The simultaneous effect of AR-components causes the maximum mutual compensation of temperature frequency shifts in the extended ∆T zone. The experimental data show the possibility realizing daily frequency instability $$\sigma _{y} \sim 1 \cdot 10^{{ - 14}}$$ of the on-board atomic clock on 87Rb cell with two dissimilar AR-components (wall coating + inert gas, 40Ar). 相似文献
977.
A. M. Semenov V. V. Anashin A. A. Zharikov A. A. Krasnov G. A. Fatkin D. B. Shwartz 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2020,14(1):13-16
In the framework of the large hadron collider (LHC) upgrade project, new materials are proposed for the vacuum. Amorphous carbon deposited onto the vacuum-chamber wall is examined as a coating with a low secondary electron emission rate for superconducting systems designed to upgrade the LHC, i.e., to increase the luminosity of the machine (HL-LHC). Since protons will generate synchrotron radiation with a critical energy of ~10 eV and a flux of 1016 photon m–1 s–1, it is important to study the effect of photons on a surface covered with amorphous carbon at room and cryogenic temperatures. The construction and parameters of the setup on the new synchrotron beamline of the VEPP-2000 booster are described. The first results of measuring the photodesorption coefficient are also presented. 相似文献
978.
The inelastic coherent Mössbauer scattering (ICMS) of synchrotron radiation at an isotopic boundary—a flat interface between two regions of matter which have different concentrations of the Mö ssbauer isotope—is investigated theoretically. Attention is focused primarily on the ICMS component for which the absorption of a synchrotron radiation photon by a nucleus occurs with recoil, i.e., with the creation or annihilation of lattice phonons, and the subsequent process of reemission of a photon by the Mössbauer nucleus occurs without recoil, as a result of which radiation is pumped from the wide synchrotron radiation line into the narrow Mö ssbauer line. Formulas similar to the Fresnel formulas, well known in optics, for the transmission and reflection of light at a dielectric boundary are obtained for ICMS at an isotopic boundary. Specifically, it is shown that the angle of reflection for ICMS at an isotopic boundary is different from the angle of mirror reflection of a synchrotron radiation beam, and the direction of the ICMS transmitted through the isotopic boundary depends on the deviation of its frequency from the exact value of the Mössbauer resonance frequency and in general is different from the direction of propagation of the synchrotron radiation beam. The suppression of ICMS at grazing angles of incidence of the synchrotron radiation beam is analyzed. A similar problem is solved for a plate-shaped sample containing a Mössbauer isotope. It is shown that the specific nature of the ICMS at an isotopic boundary could be helpful in the problem of Mö ssbauer filtering of synchrotron radiation. 相似文献
979.
The a, b, c, and β crystallographic parameters of the (CH3)2NH2Al(SO4)2 · 6H2O crystal (DMAAS) have been measured by x-ray diffraction in the 90–300-K temperature range. The thermal expansion coefficients along the principal crystallographic axes αa, αb, and αc have been determined. It was shown that, as the temperature is increased, the parameter α decreases and b increases, whereas c decreases for T<T c (where T c is the transition temperature) and increases for T>T c, so that one observes a minimum in the c=f(T) curve in the region of the phase transition (PT) temperature T c ~ 152 K. The thermal expansion coefficients αa, αb, and αc vary in a complicated manner with increasing temperature, more specifically, αa and αc assume negative values at low temperatures, and the αa=f(T), αb=f(T), and αc=f(T) curves exhibit anomalies at the PT point. The crystal has been found to be substantially anisotropic in thermal expansion. 相似文献
980.
In the single-configuration approximation, fine-structure parameters are calculated semiempirically in the intermediate coupling scheme for the configurations 2p 5 nf(n=4–6) of NeI, 3p 5 nf(n=4–7) of ArI, and 4p 54f of KrI. With the fine-structure parameters obtained, the coefficients of expansion of the wave functions in basis functions of the LS-coupling scheme and the gyromagnetic ratios are calculated. To the authors’ knowledge, analogous data are absent in the literature. The correctness of the fine-structure parameters obtained is confirmed by values of the fine-splitting constant, which is well known for other configurations of rare-gas atoms with an almost filled p shell. 相似文献