三甲基膦和环氧乙烷的加成产物裂解反应机理的MNDO法研究

文中用ＭＮＤＯ方法研究了三甲基膦和环氧乙烷加成产物裂解反应机理     

Bi3+和Eu3+在Ca2SiO4中的发光和能量传递

用高温固态反应合成了Ca2SiO4:Bi3+,Ca2SiO4:Eu3+和Ca2SiO4:Eu3+,Bi3+发光体。讨论了不同掺杂量和掺杂种类时Bi3+对Eu3+的5D0-7F1,5D0-7F2发射的影响规律。实验发现,Ca2SiO4:Bi3+在紫外线激发下发出明亮的蓝色光,Ca2SiO4:Eu3+,Bi3+中的Bi3+能将激发能传递给Eu3+,使Eu3+的5D0-7F1和5D0-7F2两种跃迁都大大加强,同时,Bi3+也发出鲜艳的紫色光。     

A quantum chaotic clock and damping of the coherent nuclear rotation in the 28 Si +64 Ni dissipative collision

We employ the statistical reactions with memory approach to study oscillating excitation functions in the ²⁸ Si(E _lab = 120–126.75 MeV)+⁶⁴ Ni strongly dissipative reaction and the time evolution of the collision process. The nonself-averaging of the oscillations in the excitation functions is interpreted as indication of quantum chaos and damping of the coherent nuclear rotation in dissipative heavy-ion collisions.     

AN INVARIANCE OF CDF EQUATION

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Barium(II)–2,4‐dinitrophenolate–18‐crown‐6 at 183 K

The title compound, bis(2,4‐dinitrophenolato‐κ²O,O′)(1,4,7,10,13,16‐hexaoxadecane‐κ⁶O)barium(II), [Ba(C₆H₃N₂O₅)₂(C₁₂H₂₄O₆)], is a 1:1 complex of barium(II)–2,4‐di­nitro­phenolate and 1,4,7,10,13,16‐hexaoxa­cyclo­octa­decane (18‐crown‐6). Its structure is located on a crystallographic inversion centre. The temperature dependence of the crystal structure has been studied. The monoclinic β angle of the P2₁/­n space group increases with increasing temperature. The packing structure of the complex is stabilized by intermolecular C—H?O interactions.     

取代基效应(SCS)与乙烯-α-烯烃共聚物的序列结构Ⅲ.定量分析

本文在分析乙烯-α-烯烃共聚物序列结构时,把代表共单体反接单元的亚甲基(CH₂)βγ和γδ分别归属给了二元组VV和三元组EEV。与此同时,CH₂-δδ和δδ⁺归属给了二元组EE。表征乙烯长序列的CH₂-δ⁺δ⁺分属二元组EE和三元组EEE,对应峰强度在EE和EEE之间的分配是处理序列分布的关键。在本文中运用序列结构的Bovey关系和Randall统计进行演算,求得了修正值△的数学表达式,严格解和近似解。在规则链条件下得到的近似解与G.J.Ray的结果完全相同。当共单体含量较少时,谱峰强度Iδ⁺δ⁺的分配接近相等。在二元组和三元组的水平上,乙烯-α-稀烃共聚物的¹³C NMR谱中共有十三个峰,属于CH₂的有十个,属于CH的有三个。利用这些谱峰的强度数据可以建立一套计算公式,由此提供共聚物序列结构的全部信息。因此这是一个研究乙烯-α-烯烃共聚物序列结构的普适方法。     

一维半导体的光学吸收

研究一维半导体在外电磁场中的光吸收、涉及电子带间的直接跃迁与间接跃迁，考虑了电子－空穴相互作用的激子光吸收，导出一维半导体的光吸收系数公式。     

A flow tube study of methyl iodine uptake on soot surface

The black carbon aerosols are now recognized for their potential impact on climate and the halogenated compounds are thought to be very important in atmospheric chemistry. However, there are very few studies on the interactions between soot aerosols and halogenated compounds. We report the measurement of the uptake of CH₃I on soot. The measured uptake coefficient is 0.0103 ± 0.0015 at a total pressure of 2–4 Torr and 298 K. The results suggest that the uptake of CH₃I occurs efficiently on soot particles. The present work suggests that heterogeneous loss of CH₃I on soot may influence the concentration of CH₃I throughout the atmosphere.     

Synthesis of 5‐Radioiodoarabinosyl Uridine Analog for Probing the HSV‐1 Thymidine Kinase Gene

Tumor cells transduced with herpes simplex virus thymidine kinase gene have been intensively applied to the field of positron emission tomography via imaging of its substrate. As a pilot synthesis approach, a facile preparation of 5‐[¹²⁵I] iodoarabinosyl uridine starting from commercially available uridine is reported herein.     

原子力显微术轻敲模式中探针样品接触过程及相位衬度研究

借助简单的有阻尼受迫振子模型，研究了原子力显微术轻敲模式中探针与样品接触时间t_c、样品的表面形变D_z和相位衬度对探针设置高度z_c及样品杨氏模量E_s的依赖关系.结果发现,t_c与D_z均随E_s及z_c的增大而减小，同时探针与样品作用过程伴随很小的能量耗散.对轻敲过程中相移量φ的研究表明，E_s较大的样品有较小的φ，且φ随 关键词： 原子力显微术 轻敲模式 相位衬度