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131.
A model of the cluster radioactivity of even—even nuclei is presented. In this model, zero-point vibrations in the charge-asymmetry coordinate determine spectroscopic factors, while tunneling in the coordinate of the relative separation of the centers of mass of the cluster and the daughter nucleus determine the penetrability of the barrier of the nucleus-nucleus potential. The conservation of the total spin and energy in the decay process is taken into account. The potential of the model for describing experimental half-lives is demonstrated. A number of predictions for possible cluster-emission reactions in the regions of lead and tin radioactivities are made. 相似文献
132.
G. A. Mironova V. N. Kuklin E. N. Kirillova B. A. Ivin 《Chemistry of Heterocyclic Compounds》1986,22(1):1-13
Literature reports on the methods of synthesis, chemical properties, and tautomerism of oxo- and thioxo-1,3-thiazines have been summarized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 3–16, January, 1986. 相似文献
133.
The cold cluster decay model is presented in the framework of a dinuclear system concept. Spectroscopic factors are extracted from barrier penetrabilities and measured half-lives. The deformation of the light cluster and residual nucleus is shown to affect the nucleus-nucleus potential and decay characteristics. Half-lives are predicted for neutron-deficient actinides and intermediate-mass nuclei. The connection between spontaneous fission and cluster radioactivity is discussed. 相似文献
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A. N. Kondratenko V. M. Kuklin I. P. Panchenko S. M. Sevidov 《Russian Physics Journal》1987,30(5):433-437
The conditions of existence of stable formations of charged particles (clusters) moving in a plasma-like medium are discussed in this paper. The interaction of clusters is considered in the framework of a one-dimensional model. It is shown that the stability of a cluster depends strongly on the number of particles that form part of it. When two clusters moving with respect to each other interact, they break up if the relative velocity is fairly low. Fast-moving clusters hardly interact with each other.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 83–87, May, 1987. 相似文献
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通过固定化酶Novozyme435(NV435)催化聚乙二醇(PEG)开环聚合己内酯(CL)得到端基带有羟基的ABA型三嵌段聚合物,用2,2-二氯代乙酰氯将聚合物的端羟基功能化形成H型大分子引发剂,在CuCl/HMTETA体系中引发4-乙烯基吡啶(4VP)进行原子转移自由基聚合反应(ATRP),得到了具有两亲性的H型五嵌段聚合物(PVP)2-b—PCL-b.PEG-PCL-(PVP)2,用红外光谱(FT IR),核磁共振(^1H NMR),凝胶渗透色谱(GPC)对其结构与分子量及其分子量分布进行了表征,结果表明:H型五嵌段聚合物分子量46121g/mol,分子量分布1.30.并利用动态光散射(DLS)和原子力显微镜(AFM)对聚合物在水溶液中的自组装行为进行了研究,H型嵌段聚合物的胶束呈球形结构,平均直径为70nm左右. 相似文献
139.
Mixed-metal carbonyl clusters of W2Ir2(CO)10(η^5-C5H4Me)2 1 and W2Ir2(μ-L)(CO)8(η^5-C5H4Me)2 (L = dppe 2, dppf 3) have been studied by TDDFT method focusing on their electronic and nonlinear optical properties. These three clusters exhibit the first static hyperpolarizabilities of medium magnitude (βtot-10×10^-30 esu). The origin of β is discussed by the new proposed orbital-pair decomposition scheme by Barandes et al. The result suggests that the β values of the two clusters are mainly originated from d-d electron transition within the metal skeleton, and d-p (π*) electron transition from metals to carbonyls and phenyl. The additional coordination by the electron donor group, ferrocene, makes cluster 3 own much larger β values, and the relatively longer range charge transfer from d orbitals of ferrocene to d orbirals of Ir and W is responsible for the enhanced β values. 相似文献
140.