排序方式: 共有26条查询结果,搜索用时 23 毫秒
1.
2.
3.
4.
S. Pellegrin A. Sarfati V.M. Akulin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(1):95-98
We consider interaction of a single level with a broad, tending to semi-infinite continuum. In an example of two exactly solvable
problems, we show that for time dependent quantum systems the probability of the irreversible transition from a discrete level
to a continuum is strongly inhibited or even completely suppressed by the presence of a discrete adiabatic level near the
continuum edge.
Received 10 October 2002 Published online 4 March 2003
RID="a"
ID="a"e-mail: Alain.Sarfati@lac.u-psud.fr 相似文献
5.
Akulin Yu. I. Strelets B. Kh. Éfros L. S. 《Chemistry of Heterocyclic Compounds》1977,13(11):1198-1201
The corresponding 6-arylamino derivatives were obtained by reaction of 6-chloro, 6-bromo, and 6-methoxy derivatives of benzo-1,2,3-dithiazolium and their selenium analogs — benzo-1,2,3-thiaselenazolium, benzo-2,1,3-thiaselenazolium, and benzo-1,2,3-diselenazolium salts — with aromatic amines. The 6-methoxy derivatives also react with acetates of secondary aliphatic amines, whereas in the case of the chloro derivatives attack is directed to the heteroring. 6-Aryl(dialkyl)amino derivatives of dithiazolium and 1,2,3-thiaselenazolium salts are protonated in concentrated sulfuric acid at the exocyclic nitrogen atom. The analogous derivatives of 2,1,3-thiaselenazolium and diselenazolium salts under the same conditions form a tautomeric mixture of dications, the position of the equilibrium between which depends on the substituent. The electronic and PMR spectra of the amination products are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1499–1502, November, 1977. 相似文献
6.
Electroreduction of benzo-1,2,3-dithiazolium salts and their selenium analogs in nonaqueous solution
V. Sh. Tsveniashvili M. V. Malashkhiya V. N. Gaprindashvili B. Kh. Strelets M. M. Gel'mont Yu. I. Akulin 《Chemistry of Heterocyclic Compounds》1985,21(2):181-184
The electroreduction of benzo-1,2,3-dithiazolium cations and their selenium analogs in aprotic solvents takes place in two steps. The first step is a reversible, one-electron transfer leading to the formation of stable radicals detected by EPR. As a result of further electroreduction, the radicals obtained combine with six electrons to form the corresponding o-aminothio(seleno)phenols. Analysis of the reduction potentials of the compounds studied shows that the substitution of a selenium atom for a sulfur in these cations, especially in the 2 position of the heterocycle, facilitates their electrochemical reduction. The electrochemical activity and the kinetics of nulceophilic substitution in the cations studied are compared.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 219–222, February, 1985. 相似文献
7.
We use tools of the equilibrium statistical mechanics of disordered systems to study analytically the statistical properties of an ecosystem composed of N species interacting via random mutual interactions, as well as via deterministic self-interactions of order p>/=2. We show that the main effect of increasing the order of the interactions among the species is to make the system less competitive, in the sense that the fraction of extinct species is greatly reduced. In addition, we find that for p>2 there is a threshold value which gives a lower bound to the concentration of the surviving species, preventing then the existence of rare species and, consequently, increasing the robustness of the ecosystem to external perturbations. 相似文献
8.
L. S. Éfros B. Kh. Strelets Yu. I. Akulin 《Chemistry of Heterocyclic Compounds》1976,12(10):1128-1131
The reaction of selenious acid on benzo-1,2,3-dithiazolium salts (Herz salts) gives benzo-1,2,3-thiaselenazolium salts, which were previously obtained from o-aminothiophenols. This reaction, which involves exchange of sulfur by selenium in the heteroring, occurs only under conditions in which the products of hydrolysis of the Herz salts —benzo-3H-1,2,3-dithiazole 2-oxides- are in equilibrium with them.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1361–1364, October, 1976. 相似文献
9.
10.
Allison M Fox Mike Anderson Corinne Reid Tim Smith Dorothy VM Bishop 《BMC neuroscience》2010,11(1):1-15