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排序方式: 共有497条查询结果,搜索用时 15 毫秒
1.
S. Ya. Gus'kov M. Yu. Mazur Yu. A. Mikhailov V. B. Rozanov A. V. Rode A. V. Sartori G. V. Sklizkov 《Journal of Russian Laser Research》1990,11(5):392-406
The preheating level of the thermonuclear fuel and of the gas-compressing shell is the main criterion of the target-compression efficiency in experiments on laserdriven thermonuclear fusion. This paper contains the result of investigations of electronic, radiative, and impact preheating in experiments on compression and heating of hlgh-aspect shell targets in the Del'fin-l laser-derived thermonuclear facility. A procedure, based on analysis of the epithermal emission of the plasma, is considered for measuring the target preheating by fast electrons. The radiative and impact preheating of compressing shells in DD gas are estimated. The results of the investigation demonstrate the high degree of adiabaticity of the compression of the thermonuclear fuel in experiments with the Del'fin-l facility.Nuclear Plasma Laboratory of the Lebedev Physics Institute. Translated from Preprint No. 3, Lebedev Physics Institute, Academy of Sciences of the USSR, Moscow, 1990. 相似文献
2.
P. M. Kochergin I. A. Mazur G. K. Rogul'chenko E. V. Aleksandrova B. E. Mandrichenko 《Chemistry of Heterocyclic Compounds》2001,37(2):224-226
Two novel preparative methods have been developed for the synthesis of 2,3-dihydroimidazo[1,2-a]pyrimidine from 2-aminopyrimidine. These are the reaction with 1,2-dibromoethane and also the reaction with ethylene chloro(bromo)hydrin, subsequent treatment of 1--hydroxyethyl-2-imino-1,2-dihydropyrimidine with thionyl chloride, and cyclization of the intermediate 1--chloroethyl-2-imino-1,2-dihydropyrimidine in the presence of sodium hydroxide. 相似文献
3.
L. Margulies N. Friedman M. Sheves Y. Mazur M.E. Lippitsch M. Riegler F.R. Aussenegg 《Tetrahedron》1985,41(1):191-195
Linear dichroism spectra of several retinoids and related polyenes incorporated in stretched polyethylene films were determined. It is suggested that the retinoids are oriented with the plane of the ring parallel to the stretching direction of the film, the long polyene chain being displaced from that direction. 相似文献
4.
Rahimipour S Litichever-Coslovsky N Alaluf M Freeman D Ehrenberg B Weiner L Mazur Y Fridkin M Koch Y 《Photochemistry and photobiology》2005,81(2):250-258
A combination of light, oxygen and a photosensitizer is used to induce death of cancer cells by photodynamic therapy. In this study, we have synthesized several new methyl helianthrone derivatives and compared their phototoxicity with that of hypericin. In contrast to hypericin, methyl helianthrones are soluble in aqueous solutions and have a broad range of light absorbance, which allows the use of polychromatic light. Structural modifications of methyl helianthrone demonstrated that substitution of hydrogen atoms of methyl helianthrone at Positions 2 and 5 with Br atoms or methylation of its phenolic hydroxyls, significantly increases the corresponding singlet oxygen quantum yield and their phototoxicity toward alphaT3-1, M2R and LNCaP cells. The phototoxicity of some of these compounds was similar to that of hypericin. Methyl helianthrones, like hypericin, accumulated mainly in the perinuclear region as evident by confocal microscopy. Irradiation of cells pretreated with methyl helianthrone derivatives generates intracellular reactive oxygen species and lipid free radicals, as shown by a fluorescentic probe and electron paramagnetic resonance methods, respectively. The phototoxicity of these methyl helianthrones as well as their ability to oxidize membrane lipids were significantly decreased on addition of specific Type-II inhibitors, suggesting the involvement of singlet oxygen as the main oxidant. 相似文献
5.
Dan Veierov Tuvia Bercovici Ernst Fischer Yehuda Mazur Amnon Yogev 《Helvetica chimica acta》1975,58(4):1240-1243
Enol-esters 1a-1e undergo clean Photo-Fries-rearrangements without side reactions. With anthroyl derivatives the reaction is observed only at 254 nm, not at 366 nm. 相似文献
6.
7.
K. I. Dikovskaya I. V. Turovskii T. V. Mazur Ya. F. Freimanis 《Chemistry of Heterocyclic Compounds》1993,29(8):878-882
A study was made of the condensation of bicyclic -lactone I with furylacrolein and furylpropionic aldehyde. Significant differences were observed in the reactivity of the aldols obtained, and in the stereochemical trend of their dehydration reaction.For Communication 35, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1035–1039, August, 1993. 相似文献
8.
Owczarek E Kwiatkowski W Lemieszewski M Mazur A Rostkowski M Paneth P 《The Journal of organic chemistry》2003,68(21):8232-8235
Nitrogen, deuterium, halogen, and carbon kinetic isotope effects have been modeled for the Menshutkin reaction between methyl halides and substituted N,N-dimethylaniline at the HF/6-31G(d) level of theory augmented by the C-PCM continuum solvent model for several solvents. Systematic changes in geometries of the transition states and Gibbs free energies of activation have been found with phenyl ring substituents, solvent, and the leaving group. Kinetic isotope effects also change systematically; however, these changes are predicted to be small, inside the usual precision of the experimental measurements. On the contrary, no correlation has been found between the kinetic isotope effects and the Hammett constants for para substituents. Thus opposite to previous assumptions, our results indicate that kinetic isotope effects on the Menshutkin reaction cannot be used to predict the position of the transition state on the reaction coordinate. 相似文献
9.
A new, precise photoelectric method of electron attenuation length measurement in alkali halides is proposed and experimentally verified. The obtained results confirm the Llacer-Garwin theory of electron-phonon interactions in these substances. 相似文献
10.
Ryszard Mazur 《Mathematische Nachrichten》1980,99(1):355-361
Let Q(D) be a class of functions q, q(0) = 0, |q(z)| < 1 holomorphic in the Reinhardt domain D ? C n, a and b — arbitrary fixed numbers satisfying the condition — 1 ≤ b < a ≤ 1. ??(a, b; D) — the class of functions p such that p ? ??(a, b; D) iff for some q ? Q(D) and every z ? D. S*(a, b; D) — the class of functions f such that f ? S*(a, g; D) iff Sc(a, b; D) — the class of functions q such that q ? Sc(a, b; D) iff , where p ε ??(a, b; D) and K is an operator of the form for z=z1,z2,…zn. The author obtains sharp bounds on |p(z)|, f(z)| g(z)| as well as sharp coefficient inequalities for functions in ??(a, b; D), S*(a, b; D) and Sc(a, b; D). 相似文献