Ph3PAuX和Ph3AsAuX(X=C1,Br)的最低三重激发态

分子水平上的激发态理论研究能够用来解释分子材料的多色发光机理.采用单组态相瓦作用方法,计算研究了四种二配位的An(Ⅰ)配合物Ph3PAuCl,Ph3PAuBr,Ph3AsAuCl和Ph3AsAuBr的分子结构限制的三重激发态(T1a)和分子结构松弛的三重激发态(T1b)的分子结构与光物理性质.由于θ(PAuX)/θ(AsAuX)从180°扭曲到120°左右,T1b态的能量在单线态组态相互作用(CIS)水平上降低了0.805-1.124 eV,在密度泛函理论(DFT)水平上降低了0.820-0.947 eV.自然键轨道电荷布居数分析表明,在T1a态中两个单电子主要分布在一个苯基上,而在T1b态中两个单电子分布在PAuX/AsAuX上.因此,在晶体中观察到的较高能磷光归属于T1a态的苯基之间的3π*→1π电子跃迁,而较低能磷光主要起源于T1b态的Au的3σ*→1σ电子跃迁.     

气相色谱法同时测定动物饲料中安定和三唑仑残留量

提出了气相色谱法同时测定动物饲料中安定和三唑仑的残留量的方法。饲料经过有机溶剂提取,采用SE-54毛细管柱(30 m×0.32 mm,0.32μm)分离,电子捕获检测器检测,外标法定量。安定和三唑仑的质量浓度均在0.3～60 mg·L~(-1)范围内与其峰面积呈线性关系,检出限(2SN)分别为0.007 1,0.021 3 mg·L~(-1)。方法的平均回收率分别为79.5%～93.1%,81.6%～91.8%,相对标准偏差(n=8)分别为2.11%～4.02%,2.09%～4.61%。     

基于非单一类型的组合模型在回归分析中的应用

本文研究的是非单一类型的组合模型应用于回归预测的问题.利用不同类型的子模型来构建组合模型,最大程度上减小了子模型间的相关性,得到了具有更好泛化能力的组合模型这一结果,在预测分析中具有重要的指导意义.     

Nafion修饰电极阴极溶出伏安法测定痕量钛

本文采用Ｎａｆｉｏｎ修饰玻碳电极阴极溶出伏安法测定痕量钛。研究了Ｎａｆｉｏｎ膜的有关特性和测定的佳化条件。当富集时间为１ｍｉｎ时，Ｔｉ（Ⅳ）浓度与峰电流在１．０～５０ｎｇ／ｍｌ范围内呈线性关系。本法应用于铝合金和白泥标样中钛的测定，结果满意。     

NaY超笼内[Pt_3(CO)_3(μ_2-CO)_2]_n~(2-)(n=3,4)簇合物的合成、表征及其催化CO+NO的反应性能

在NaY分子筛超笼内合成了桔黄色的[Pt_9(CO)_(18)]~(2-)和深绿色的[Pt_(12)(CO)_(24)]~(2-)簇合物。前者给出2056和1798cm~(-1)的线式和桥式羰基特征红外谱带;后者给出2080和1824cm~(-1)谱带。与在THF溶液中结果相比,NaY内合成的羰基簇合物的线式v_(CO)向高波数位移,而桥式v_(CO)向低波数位移。EXAFS为Pt羰基簇合物在分子筛内的规整形成提供了证据。NaY内Pt_9和Pt_(12)羰基簇合物在NO+CO反应中显示了较高的催化活性及稳定性。     

SYNTHESIS AND STRUCTURE OF CARBON NANOTUBES

The distribution, morphology and structure of carbon nanotubes and buckyonions produced from an arc discharge were investigated by means of scanning electron mi-croscopy and high-resolution transmission electron microscopy, The nanotubes and nanoonions were found to be located mainly near the porous region of the core in the deposited rods and the transition region between the growth ring-shaped graphite sheets. The tube bundles grew freely from carbon particles. Apart from the straight-line tubes, curved and bent tubes were also found. Studies on the structure of them showed that the carbon atomic sheets in the nanotubes displayed a stepped bending. Transverse sectional study predicted a helical structure of the carbon atomic sheets. In addition, the relationship between the number of pentagonal rings and cone angle at the tips of the tubes, as well as the mechanism of the formation of the steplike structure, were discussed.     

Γ函数乘积公式的一个新证明

Γ函数的乘积公式的证明方法有多种.例如,依据Γ函数对数微商的表达式     

INVESTIGATIONS ON THE CRYSTAL STRUCTURE OF 2-(m-CYANOPHENYL)-5-CYANOBENZOTHIAZOLE AND CONFORMATIONS OF ITS ISOMERS

The crystal structure of 2-(m-cyanophenyl)-5-cyanobenzothiazole has been determined by X-ray single crystal diffraction method and its conformational analysis and its two isomers have been carried out by employing the PCILO method. The crystal of title compound belongs to the monoclinic system, space group P2_1/c, a=23.793(7), b=3.852(1), c=27.004(11), β=98.40°(3), Z=8, D_(calc). =1.42g/cm~3, F(000)=1072, the final β=0.048. The crystals of this molecule and its two isomers belong to a same space group, but the packing schemes of the molecules in the unit cell, the separations and the mutual orientation of-C≡N bonds are not same. From the detailed analysis and comparison of their packing schemes in crystal, it can be considered that they may be possible to polymerize to different extent in the solid state by appropriate energy stimulation.