排序方式: 共有13条查询结果,搜索用时 46 毫秒
1.
Fedyushin P. A. Serykh A. A. Vinogradov A. S. Mezhenkova T. V. Platonov V. E. Nasyrova D. I. Samigullina A. I. Fedin M. V. Zayakin I. A. Tretyakov E. V. 《Russian Chemical Bulletin》2022,71(8):1670-1678
Russian Chemical Bulletin - A method was developed for the synthesis of perfluoro-1,1′:4′,1″-terphenyl by the reaction of chloroperfluorobenzene with zinc dust followed by the... 相似文献
2.
S.I. Zhivetyeva I.A. Zayakin I.Yu. Bagryanskaya E.V. Zaytseva E.G. Bagryanskaya E.V. Tretyakov 《Tetrahedron》2018,74(28):3924-3930
A 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl lithium derivative was found to react with 2-methoxypentafluoro-1,4-naphthoquinone to form a product of addition at the carbonyl function: radical 2-(3,5,6,7,8-pentafluoro-1-hydroxy-2-methoxy-4-oxo-1,4-dihydronaphthalen-1-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl. The yield of the addition product increased with temperature and reached 84% at 0?°C. The reaction of the lithium derivative with hexafluoro-1,4-naphthoquinone gave rise to a product of addition at both carbonyl groups, namely, nitronyl nitroxide diradical 2,3,5,6,7,8-hexafluoro-1,4-bis(4,4,5,5-tetramethyl-3-oxide-1-oxyl-4,5-dihydro-1H-imidazole-2-yl)-1,4-dihydronaphthalene-1,4-diol in a 16% yield. The structures of both mono- and diradical were solved by X-ray diffraction analysis, which revealed formation of an intramolecular H-bond between the OH group and nitroxide oxygen. According to electron paramagnetic resonance (EPR) spectroscopy, the obtained mono- and dinitroxide are prone to spontaneous deoxygenation in a toluene solution to give corresponding iminonitroxides. In water, they are much more stable. 相似文献
3.
B. G. Milevsky N. P. Solov’eva T. A. Chibisova V. N. Yarovenko E. S. Zayakin V. V. Chernyshev M. M. Krayushkin V. F. Traven 《Russian Chemical Bulletin》2012,61(12):2311-2321
Novel hydrazones were obtained from thiooxamohydrazides and 3-3-formyl-4-hydroxycoumarin. According to data from NMR spectroscopy and X-ray diffraction, the coumarin fragment in the compounds obtained exists as 4-hydroxycoumarin or chromane-2,4-dione. When dissolved in dimethyl sulfoxide, these hydrazones undergo fragmentation into derivatives of 1,3,4-thiadiazole and 4-hydroxycoumarin. 相似文献
4.
Results of experiments on wavefront formation using multichannel modal correctors in an adaptive optical system with feedback
are reported. Two types of correctors, one based on a glass substrate with a high-resistance layer deposited onto it and the
other based on a high-permittivity ceramic substrate, are developed and investigated. The results show that it is expedient
to use the correctors in applications that do not require a high speed of response. 相似文献
5.
G. V. Vdovin I. R. Guralnik O. A. Zayakin N. A. Klimov S. P. Kotova M. Yu. Loktev A. F. Naumov V. V. Patlan S. A. Samagin 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(1):71-77
The results of the development of modal liquid crystal wavefront correctors are reviewed. The modal principle of control is described. Characteristics and examples of application of electrically and optically controlled lenses and multichannel correctors with a tunable response function in different systems are reported. 相似文献
6.
The rate of monopole decay into a dyon and an electron in an inhomogeneous external electric field is calculated by semiclassical
methods. Comparison is made to an earlier result where this quantity was calculated for a constant field. Experimental and
cosmological tests are suggested.
The text was submitted by the authors in English. 相似文献
7.
8.
Fedyushin P. A. Zayakin I. A. Tolstikov S. E. Lalov A. V. Akyeva A. Ya. Syroeshkin M. A. Romanenko G. V. Tretyakov E. V. Egorov M. P. Ovcharenko V. I. 《Russian Chemical Bulletin》2022,71(4):722-734
Russian Chemical Bulletin - New nitronyl nitroxide radicals, 2-(4′(5′)-methylimidazol-2′-yl)- and... 相似文献
9.
A. V. Zayakin 《Physics of Particles and Nuclei Letters》2007,4(3):232-238
Nonperturbative particle production in external variable fields is important in astrophysics. Although a wide range of techniques
exists for calculating production rate, none of them can handle exactly the case of a strongly inhomogeneous field. Here,
an electric field with an abrupt switch-on is considered. First, a standard semiclassical technique is used. Then, a scattering
problem approach to this case is developed and time-dependent corrections to the effective Euler-Heisenberg-Schwinger Lagrangian
are calculated.
The text was submitted by the author in English. 相似文献
10.
The problem of diffraction of a spherical wave with Gaussian amplitude distribution on two infinitesimally thin and ideally reflecting screens with apertures on an optical axis is solved within the framework of the quasi-optical approximation. It is shown theoretically and experimentally that when a Gaussian beam illuminates such a type of bicomponent diffraction system with small Fresnel numbers in a near zone of the second screen, the effect of diffractive multifocal focusing of radiation is observed. In this case, the diffraction picture from the second screen in the focal planes represents the circular nonlocal bands of the Fresnel zones with a bright narrow peak at the center, whose intensity can exceed by six times the value of the incident wave intensity. The energy efficiency of diffractive focusing of Gaussian beams by the bicomponent diffraction system can be as high as 70%. The diffractive method proposed allows the focusing of wide-aperture beams without using classical refraction elements such as lenses and prisms, and it is applicable to both low-intensity and high-power radiation. 相似文献