NASICON型化合物结构的NMR研究

在水热晶化合成一系列NASICON型化合物的基础上,应用固体高分辨³¹P和²⁹Si MAS NMR,研究了几种NASICON化合物的结构,观察其骨架原子P和Si在结构中的状态及分布,并解释了由于在结构中发生取代作用而引起,Si或P的化学位移的变化.     

汉折射波片用于发散光束的偏振像差分析

本文利用光线追迹法,对双折射波片用于发散光束的偏振像差进行了分析,并以标准1/4波片为例,给出了小角入射时的近似处理方法.     

用2D-NMR研究暗霉素T的化学结构

该文用NMR方法研究暗霉素T的化学结构.从1D谱和几种2D技术确认了暗霉素T是氨基糖苷类化合物.讨论了化合物的构型,并通过改变溶剂推断了氨基的连接位置.     

N-[(2,2–propinyldiferrocenyl)methinyl]benzoyl hydrazone and its bivalent transition metal complexes

Transition Metal Chemistry -     

Determination of the portfolio selection for a property-liability insurance company

This paper presents an analysis of a portfolio model which can be used to assist a property-liability insurance company in determining the optimal composition of the insurance and investment portfolios. By introducing insurer's threshold risk and relaxing some non-realistic assumptions made in traditional chance constraint insurance and investment portfolio models, we propose a method for an insurer to maximize his return threshold for a given threshold risk level. This proposed model can be used to optimize the composition of underwriting and investment portfolios regarding the insurer's threshold risk level, as well as to generate the efficient frontier by adjusting insurer's threshold risk levels. A numerical example is given based on the industry's aggregated data for a sixteen year period.     

Exact boundary observability for 1‐D quasilinear wave equations

By means of a direct and constructive method based on the theory of semi‐global C² solution, the local exact boundary observability and an implicit duality between the exact boundary controllability and the exact boundary observability are shown for 1‐D quasilinear wave equations with various boundary conditions. Copyright © 2006 John Wiley & Sons, Ltd.     

Electron attenuation lengths in fullerene and fullerides

Using X-ray photoemission measurements, we have determined the attenuation length of C 1s photoelectrons in C₆₀ film to be 21.5 Å with the incident photon energy of Mg Kα radiation. The inelastic mean free path calculated with the TPP-2M algorithm coincides fairly well with the experimentally determined attenuation length, indicating the validity of the algorithm to fullerene and fullerides. The inelastic mean free paths for some fullerides, i.e. K₃C₆₀, K₆C₆₀, Ba₄C₆₀, Sm_2.75C₆₀ and Sm₆C₆₀ are calculated to help the quantitative analyses of the photoemission spectra for these compounds.     

Effect of nitrogen surface doping on the work function and field emission of hydrogenated amorphous carbon films

The effect of nitrogen surface doping on the electron field emission characteristics of hydrogenated amorphous carbon films was studied. It was found that the emission threshold electric field decreased after nitrogen surface doping which indicated the reduction of the emission barrier at the film surface. It was demonstrated that this improvement arose from the decrease of the effective work function due to the formation of a dipole layer induced by chemical termination and chemical structural change on the film surface. PACS 52.75.Xx; 73.30 +y; 73.61.Jc