提高风险投资过程中两级委托—代理效率的思考

本文从对风险投资者与风险投资商、风险投资商与风险企业之间的两层委托代理的简要分析入手 ,首先在诠释委托—代理效率内涵的基础上构建了分析委托—代理效率的一个理论框架 ,并应用此框架对如何提高上述两层委托—代理关系的效率问题进行了探讨     

Study of asymmetric charge writing on Pb(Zr,Ti)O3 thin films by Kelvin probe force microscopy

Polycrystalline Pb(Zr_0.55Ti_0.45)O₃ thin film was deposited on Pt/Ti/SiO₂/Si(1 0 0) by radio-frequency-magnetron sputtering method, and the writing of charge bits on the surface of PZT thin film was studied by Kelvin probe force microscopy. It is found that the surface potential of the negative charge bits are higher than those of the corresponding positive ones. When ferroelectric polarization switching occurs, the potential difference becomes even more remarkable. A qualitative model was proposed to explain the origin of the asymmetric charge writing. It is demonstrated that the internal field in the interface layer, which is near the ferroelectric/electrode interface in ferroelectric film, is likely to be the cause for the occurrence of this phenomenon.     

FORTRAN程序调用C语言函数过程的方法

本文介绍FORTRAN语言调用C语言过程的方法。     

Adducts of Rh2[MTPA]4 with some phosphine chalcogenides: nature of binding and ligand exchange

Adducts of four phosphine chalcogenides with the chiral dirhodium complex ([Rh-Rh]) were investigated by variable-temperature 1H and 31P NMR spectroscopy in order to compare their properties as axial ligands. Whereas the selenide (1) and the sulfide (2) are strong ligands with electrostatic attraction and, in addition, a significant orbital (HOMO-LUMO) interaction, the phosphine oxide compounds (P=O) bind primarily via electrostatic attraction and are relatively weak donors. Moreover, the overall bond strength in these adducts depends on steric congestion around the P=O group.     

Multipole expansion of diatomic overlap

A systematic extension of Ruedenberg's expansion formula is applied to evaluate two-electron integrals occurring in calculations on molecular structure. Minimum STO basis sets are used for all SCF-calculations within the framework of the MEDO-method (Multipole Expansion of Diatomic Overlap). The errors due to this approximation scheme are almost negligible compared to those introduced by the truncated basis set: LiH, Li₂ and N₂ are chosen as examples.     

Reaktionen von Tetraphosphortrichalkogeniden mit Alkyliodiden

Reactions of Tetraphosphorus Trichalcogenides with Alkyl Iodides Reactions of alkyl iodides RI (R = CHI₂, CH₂I or tert-Butyl) with P₄E₃ (E = S or Se) under the influence of light resulted in cleavage of the basal P₃ ring. β-P₄E₃(I)R was formed initially, then it rearranged to the more stable α-P₄E₃(I)R structure. ³¹P NMR data of these products were measured and discussed, along with ⁷⁷Se data for α- and β-P₄⁷⁷SeSe₂(I)CHI₂. On reaction of P₄S₃ with tert-butyl iodide in CS₂ or with sec-butyl iodide or iso-propyl iodide in dioxane, the new type of compounds P₅S₂R was observed. In this a sulfur bridge of P₄S₃ is replaced by a P? R group. ³¹P-NMR data for these compounds are reported.     

电化学方法合成有机物综合实验设计与评价

本文提出在现有仪器设备基础上,改革传统实验教学模式,在化学专业高年级开设综合性实验,以便培养具有创新精神、创新意识、创新能力的适应素质教育需要的高质量人才。文章给出了综合实验设计方案并对其进行了分析、评价。     

MATLAB与C/C++、FORTRAN语言混合编程

对MATLAB与C／C 和FORTRAN语言进行混合编程的常用方法进行了介绍，分析了其实现方式和各自的利弊，并用实例对MEX文件实现方式进行了较详细的论述．     

塔里木盆地库车褶皱冲断带的构造特征与油气聚集

根据地面地质调查和地震剖面解释 ,认为库车褶皱冲断带具有分带组合的构造特点 ,即由南侧的滑脱褶皱和北侧的断展褶皱相互匹配 ,实例有喀桑托开背斜与吉迪克背斜、吐孜麻扎背斜与大宛齐背斜、亚克里克背斜与米斯坎塔格背斜以及东秋里塔格背斜与亚肯背斜等 .除了南北分带、上下分层和东西分段特征外 ,库车褶皱冲断带还具有构造分块特点 ,自西向东依次可分却勒、克拉、迪那和阳霞 4大区块 .库车褶皱冲断带的油气聚集主要与侧断坡相关背斜有关     

A Ten Years Monitoring of Chlorofluorocarbons at the Antarctica: Results and Perspectives

Abstract

Chlorofluorocarbons are man-made long lasting atmospheric pollutants of great environmental concern, responsible for important global change phenomena. Recently, they were replaced by hydrogenated halocarbons that, even if less persistent, do not lack in environmental impact. Atmospheric concentrations of these compounds were measured in Antarctica by gas chromatography. The extremely low atmospheric mixing ratios of these compounds require a pre-concentration step of the air sample on suitable adsorbent in order to meet the sensitivity of the analytical method Results obtained analyzing air samples collected in Antarctica since 1988 for the determination of CFC-12 and CFC-11 are reported, together with data concerning the less abundant species.