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41.
Differential Equations - We consider a control system described by a system of differential equations of retarded type with variable matrix coefficients and several delays. The relationship between... 相似文献
42.
G. G. Varzugin E. Sh. Gutshabash V. D. Lipovskii 《Theoretical and Mathematical Physics》1995,104(3):1166-1177
The investigation of the boundary-value problem on a half-plane for the two-dimensional stationary Heisenberg magnet is continued. The asymptotic behavior of N-soliton solutions is discussed. The asymptotic contribution of the continuous spectrum is calculated. The gauge equivalence of the boundary-value problems for the models of a magnet and the elliptic equation represented by the sinh—Gordon equation is considered.Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 104, No. 3, pp. 513–529, September, 1995. 相似文献
43.
Sh. A. Ehgamberdiev 《Radiophysics and Quantum Electronics》1996,39(10):817-819
This paper is devoted to the measurement of low-degree p mode rotational splitting, which is one of the most urgent problems in helioseismology. The last three years witnessed considerable progress in this field. It can be stated with confidence that the angular velocity of solar core rotation exceeds only marginally or even does not exceed the rotation velocity of the Sun envelope, except for an area of radius 0.1R
in the deep interior of the core. Further progress in this avenue encounters a variety of serious difficulties for lack of reliable data on g modes. These difficulties are due to the physical nature of the p modes themselves and the imperfection of the analytical techniques.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 39, No. 10, pp. 1218–1221, October, 1996. 相似文献
44.
Sh. Yu. Islambekov A. K. Karimdzhanov S. M. Mavlyanov A. I. Ismailov 《Chemistry of Natural Compounds》1991,26(3):239-250
Information is given on vegetable tanning substances, their classification, distribution in the plant world, and structure, and the dependence of their tanning properties on their composition, and also on methods of enriching tanning extracts. The review of literature sources includes publications from 1950 to 1989.A. S. Sadykov Institute of Bioorganic Chemistry, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 293–307, May–June, 1990. 相似文献
45.
V. A. Kiyashko A. K. Popov V. P. Timofeev N. P. Makarov V. Sh. Epstein 《Applied physics. B, Lasers and optics》1985,36(1):53-54
Generation of the second- and fourth-order harmonics of laser radiation is reported in Mg vapor at the forbidden 3s
21
S
o–4s
1
S
o transition. The conversion efficiency for the second-order harmonics has been measured to be 10–2% and for the fourth one 10–8%. 相似文献
46.
Zh. A. Abdurakhmanova L. N. Abdusalyamova V. V. Kim Sh. I. Salikhov 《Chemistry of Natural Compounds》1994,30(1):92-96
The Ca2+-phospholipid-dependent protein kinase from cottonplant shoots was purified by chromatography on DEAE-Sepharose CL-6B, and then on phenyl-Sepharose CL-4B. According to electrophoresis in PAAG, the enzyme was practically homogeneous and had a molecular mass of 57 kDa. In the presence of Ca2+ alone, the enzyme was activated to only a slight degree. Under the combined action of Ca2+ and a phospholipid the action of the enzyme rose severalfold. A determination of amino acid specificity showed that the protein kinase isolated was a serine- and threonine-specific protein kinase.A. S. Sadykov Institute of Bioorganic Chemistry, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax 627071. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 100–105, January–February, 1994. 相似文献
47.
Sal'keeva L. K. Nurmaganbetova M. T. Kurmanaliev O. Sh. Gazizov T. Kh. 《Russian Journal of General Chemistry》2002,72(11):1760-1763
Reactions of ethyl and tert-butyl phosphorodiamidites with chloroacetone, bromoacetone, and -chloroethyl acetate were studied. The reaction pathway is determined by the structure of the intermediate quasiphosphonium compound responsible for the formation of the Arbuzov product as well as for the occurrence of the amonalous reaction yielding vinyl phosphate. 相似文献
48.
49.
S. A. Talipov B. T. Ibragimov K. M. Beketov Sh. Yu. Islambekov R. G. Mardanov A. I. Ismailov 《Chemistry of Natural Compounds》1995,31(6):685-689
The results are given of an x-ray structural investigation of hemigossypolone isolated from the stems of a wiltinfected cotton plant and of gossypolone obtained by oxidizing gossypol. 相似文献
50.
N. P. Ramzaeva I. N. Goncharova M. Yu. Lidak Yu. Sh. Gol'dberg M. V. Shimanskaya 《Chemistry of Heterocyclic Compounds》1987,23(1):93-98
The mixture of 9-, 3-, and 7-benzyl-6-substituted purines is formed in almost quantitative yield by the alkylation of 6-benzylamino-, 6-furfurylamino-, 6-methylthio-, and 6-chloropurine with benzyl halides in the biphasic system of the liquid-liquid or liquid-solid type in the presence of interphase catalysts (quaternary ammonium salts, 18-crown-6). The catalytic activity of the quaternary ammonium salts increases with the increase in the lipophilicity of the cation. Taking the alkylation of 6-benzylaminopurine as an example, the possibility of the application of triphasic catalysis in the alkylation reaction of purines is indicated. The alkylation of 6-substituted purines with isopropyl bromide proceeds regioselectively under the conditions of the interphase catalysis with the formation of the corresponding 9-isopropylpurines.For the preliminary communication, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 113–118, January, 1987. 相似文献