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71.
Photolysis of S,C-sulfonium ylides derived from thioanisol, thiophene, benzothiophene, or dibenzothiophene provides products deriving from dicarbomethoxycarbene. In methanol, no rearrangement of the carbene to the ketene derivative is observed. Formation of dibenzothiophene and benzothiophene is quantitative. For the thiophene-based ylide, insertion of the carbene into the alpha-CH bond of thiophene is observed. Evidence is presented that supports formation of both singlet and triplet carbene. 相似文献
72.
LIAO Rong-Baoa b LIU Cai-Pinga b SA Rong-Jiana LI Fu-Juna b HE Jian-Ganga b WU Ke-Chena② a 《结构化学》2008,27(6):724-732
The ground-state dipole moments and second-order nonlinear optical (NLO) properties of a series of one-dimensional (1D) chromophores with donor-bridge-acceptor (D-B-A) structures have been investigated by using the second-order MФller-Plesset (MP2) and density functional theory (DFT) methods with the basis set of 6-31+G(d). According to the calculated results, the relationship between the molecular static first hyperpolarizability (βμ) and the directions of electron transition has been summarized. In terms of the sign of βμ, these 1D organic chromophores were classified into two categories: type Ⅰ with negative βμ and type Ⅱ bearing positive βμ. The analyses show that the remarkable difference of the first hyperpolarizabilities between Ⅰ and Ⅱ chromophores is associated mainly with the electrostatic interaction between terminal groups and the transport electrons in excited states. Moreover, different from the popular viewpoint, the obtained results also show that most of this series of 1D D-B-A molecules are more charge-separated in the ground states than in the excited states. As a whole, this theoretical investigation, to some extent, can be considered as a useful reference in designing the NLO chromophores with large first hyperpolarizabilities. 相似文献
73.
DS Zhulai SA Bugaychuk GV Klimusheva TA Mirnaya VN Asaula VI Handziuk 《Liquid crystals》2017,44(8):1269-1276
The class of thermotropic ionic liquid crystals (LCs) of the metal alkanoates possesses a number of unique properties, such as intrinsic ionic conductivity, high dissolving ability and ability to form time-stable mesomorphic glasses. These ionic LCs can be used as nanoreactors for the synthesis and stabilisation of different types of nanoparticles (NPs). Thus, some semiconductors, metals and core/shell NPs were chemically synthesised in the thermotropic ionic liquid crystalline phase (smectic A) of the cadmium octanoate (CdC8) and of the cobalt octanoate (CoC8). By applying the scanning electron microscopy, the cadmium and cobalt octanoate composites containing CdS, Au, Ag and core/shell Au/CdS NPs have been studied. NPs’ sizes and dispersion distribution of the NPs’ size in the nanocomposites have been obtained. 相似文献
74.
用描写相对论性核 核碰撞的LUCIAE模型及相应的MonteCarlo事例产生器分析了WA97最近发表的 1 5 8AGeVp Pb和Pb Pb碰撞中单奇异粒子 (Λ ,Λ)和多奇异粒子 (Ξ-,Ξ-,Ω-,Ω-)的多重数和横质量分布 .由于LUCIAE模型包含了弦碎裂微观过程中奇异夸克压低因子随碰撞体系的能量、中心度和质量的增大而增大 ,以及由它导致的相对论性核 核碰撞宏观过程中奇异粒子产额随上述三因素之增而增的物理机制 ;LUCIAE模型计算结果能较好描写WA97实验所揭示的相对论性核 核碰撞中奇异粒子产额随中心度之增而增和奇异粒子增强随奇异夸克数之增而增的实验事实 ,以及单奇异和多奇异粒子的横质量分布 . 相似文献
75.
76.
The dependence of phase transition,associated with the disassembly of hot nuclei,on the mass number of hot nuclei is investigated.By studying six hot nuclei ranging from 56Ni* to 238U*,we find that in the curves of excitation energy of hot nuclei vs.Thermodynamic temperature T(E*) of 63Cu* and heavier ones there are always two temperature plateaus,but in T(E*) of 56Ni the first temperature plateau (at lower excitation energy) shrinks into a kink. 相似文献
77.
ON THE BEHAVIOR OF PHASE TRANSITION SHOWN IN DISASSYMBLY PROCESSES OF VERY HOT AND DILUTE FINITE NUCLEAR SYSTEMS 下载免费PDF全文
The behaviors of phase transition shown in disassymbly processes of very hot and dilute finite nuclear system have been exposed by using canonical (microcanonical) ensemble Monte Carlo simulation.It is explained that they result from the competition between Coulomb interaction and the effect of finiteness. 相似文献
78.
IMPROVEMENT OF THERMODYNAMICAL MONTE CARLO SIMULATION IN SU(2) PURE GAUGE FIELD THEORY ——AN APPROACH TO CONTINUUM PHYSICS LIMIT 下载免费PDF全文
The thermodynamical quantities of SU(2) pure lattice gauge field have been simulated first time on the asymmetric lattice (ξ>1).The finite size effect and continuum physics limits have also been studied.The results show that the use of asymmetric lattice is of benefit to calculate the thermodynamical quantities and study the behavior of continuum physics limits.In addition,it is explained that the efficiency of the whole Monte Carlo simulation and the calculation of heat capacity will be improved quite a lot by using bias sampling technique. 相似文献
79.
Ben-Hao SA 《理论物理通讯》1997,27(4):507-510
We use the event generator LUClAE to analyze the WA85 data of ratio of Ω- to Ω- in reaction (200A GeV/c)S + W. The result indicates that the reproduction of WA85 data might be achieved in hadronic rescattering regime of LUCIAE and might need not to rely on the formation of QGP. 相似文献
80.
采用YOCl/CaO为助烧剂常压烧结制备SiC陶瓷,研究助烧剂的配比及烧结温度对陶瓷的显微结构、热学性能及介电性能的影响.结果表明:在高温烧结过程中YOCl及CaO会与SiC发生置换还原反应,生成部分含钇化合物,对比各样品的热膨胀系数发现,在1800 ℃下烧结的YOCl/CaO=4:5的样品与常压烧结制备的纯SiC热膨胀系数α=4.0×10 -6相接近,而其它样品热膨胀系数与单晶硅的热膨胀系数α=2.62×10 -6较为接近,有望成为较好的封装材料. 相似文献