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41.
42.
Zdoroveyshchev A. V. Vikhrova O. V. Demina P. B. Dorokhin M. V. Kudrin A. V. Temiryazev A. G. Temiryazeva M. P. 《Physics of the Solid State》2019,61(9):1577-1582
Physics of the Solid State - The magnetic properties of CoPt, CoPd, and FePd thin films with different contents of a ferromagnetic material fabricated by electron beam evaporation have been... 相似文献
43.
Maria V. Demina 《Studies in Applied Mathematics》2023,150(3):755-817
We provide the necessary and sufficient conditions of Liouvillian integrability for Liénard differential systems describing nonlinear oscillators with a polynomial damping and a polynomial restoring force. We prove that Liénard differential systems are not Darboux integrable excluding subfamilies with certain restrictions on the degrees of the polynomials arising in the systems. We demonstrate that if the degree of a polynomial responsible for the restoring force is greater than the degree of a polynomial producing the damping, then a generic Liénard differential system is not Liouvillian integrable with the exception of linear Liénard systems. However, for any fixed degrees of the polynomials describing the damping and the restoring force we present subfamilies possessing Liouvillian first integrals. As a by-product of our results, we find a number of novel Liouvillian integrable subfamilies. In addition, we study the existence of nonautonomous Darboux first integrals and nonautonomous Jacobi last multipliers with a time-dependent exponential factor. 相似文献
44.
45.
T. G. Deryabina M. A. Demina N. P. Belskaya V. A. Bakulev 《Russian Chemical Bulletin》2005,54(12):2880-2889
The reaction of cyanothioacrylamides with dimethyl acetylenedicarboxylate, methyl propiolate, and N-phenylmaleimide was studied. The reaction follows a cycloaddition pathway to give thiopyrans, irrespective of the electronic
or spatial effects of the substituents in the thioamide group and in position 3 of the 1-thiabuta-1,3-diene system. The reaction
is regio-and stereoselective.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2784–2792, December, 2005. 相似文献
46.
E. A. Filonova A. N. Demina A. N. Petrov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2007,81(10):1591-1594
The formation of the orthorhombic solid solution series LaMn1−y
Ti
y
O3 with 0.0 ≤ y ≤ 0.15 and LaMn1−y
Ni
y
O3 with 0.0 ≤ y ≤ 0.4 was observed. The stability boundaries of the La1−x
Sr
x
Mn1−y
M
y
O3 (M = Ti, Ni) perovskite phases were determined. Fragments of isobaric-isothermal sections of the phase diagrams of the La2O3-SrO-Mn3O4-TiO2 and La2O3-SrO-Mn3O4-NiO systems in air at 1100°C were suggested.
Original Russian Text ? E.A. Filonova, A.N. Demina, A.N. Petrov, 2007, published in Zhurnal Fizicheskoi Khimii, 2007, Vol.
81, No. 10, pp. 1787–1790. 相似文献
47.
M. M. Demina P. S. Novopashin G. I. Sarapulova L. I. Larina A. S. Smolin V. S. Fundamenskii A. A. Kashaev A. S. Medvedeva 《Russian Journal of Organic Chemistry》2004,40(12):1804-1809
Reactions of trimethylsilyl azide with 3-trimethylsilyl-2-propynal and 2-propynal were studied. X-Ray analysis of the molecular structure of 4-trimethylsilyl-1H-1,2,3-triazole-5-carbaldehyde showed that the carbonyl group appears in the s-cis conformation with respect to the double C=C bond in the heteroring. The effect of the temperature and polarity of the medium on the ability of 1H-1,2,3-triazole-5-carbaldehyde to undergo dimerization to tricyclic bis-hemiaminals was examined by IR and 1H NMR spectroscopy.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 12, 2004, pp. 1852–1857.Original Russian Text Copyright © 2004 by Demina, Novopashin, Sarapulova, Larina, Smolin, Fundamenskii, Kashaev, Medvedeva. 相似文献
48.
The authors present formulas for constructing continuous splines and smooth splines which are exact on any power of a given function. 相似文献
49.
A.S. Medvedeva M.M. Demina A.I. Borisova O.I. Margorskaya I.D. Kalikhman E.I. Brodskaya N.S. Vyazankin 《Journal of organometallic chemistry》1982,231(2):109-118
Methyl 2-diazo-3-hydroxy-6,6-dimethyl-4-heptynoate was prepared by treating 4,4-dimethyl-2-pentyn-1-al with methyl diazoacetate at room temperature in the absence of catalysts. In the case of related aldehydes, RCCCHO (R = n-Bu, Me3Si, Et3Si, Et3Ge), this unusual reaction is partially or completely suppressed by a competing 1,3-cycloaddition process. The latter leads to a mixture of isomeric 3- and 4-formylpyrazole, one of which cyalodimerizes to form tricyclic hemiaminal. 相似文献
50.
Conclusions 1. The temperature dependences obtained for the ultimate alongation, tensile strength, and elastic modulus of various polymers showed that the relationship between the mechanical properties and chemical structure of macromolecules found in our earlier work at 4.2°K is retained at 78°K and, possibly, up to 90°K.2. It was shown that the passage of the tensile strength through a maximum upon warming from 4.2°K results from a corresponding increase in deformability, which is accompanied by a decrease in the elastic modulus and deviation of the polymer bodies from Hooke's law progressively with increasing temperature.3. It was shown that the amorphization of crystallizing polymers, for example, by quenching, gives a marked change in the deformability, tensile strength, and elasticity of the polymer body over the entire range from 300 down to 4.2°K.4. Study of the mechanical properties of polymers at 78°K in a helium medium and liquid nitrogen showed a marked effect of contact of the polymer with liquid nitrogen on these properties. This effect is different for polymers of varying chemical structure as well as for the same polymer in different physical states.Report presented at the Third All-Union Conference on Polymer Mechanics, Riga, November 10–12, 1976.L. Ya. Karpov Scientific-Research Institute of Physical Chemistry, Moscow. Translated from Mekhanika Polimerov, No. 3, pp. 387–391, May–June, 1977. 相似文献