On order-preservation and positive correlations for multidimensional diffusion processes

Summary As a continuation of the study by Herbst and Pitt (1991), this note presents two criteria. The first one is on the order-preservation for two (may be different) multidimensional diffusion processes. The second one is on the preservation of positive correlations for a diffusion process.Research supported in part by the Ying-Tung Fok Educational Foundation and the National Natural Science Foundation of China     

最大度为6的极大外平面图的完备色数

证明了最大度为６的极大外平面图的完备色数为７。     

高精度CCD尺寸自动检测系统的光学系统设计

介绍测量精度为±０．００３ｍｍ的ＣＣＤ尺寸检测系统的光学系统设计特点及远心物镜设计原理，并给出了测试结果。     

Synthesis of a new class of uridine phosphorylase inhibitors

A new series of potent uridine phosphorylase inhibitors have been prepared from barbituric acid. Among them, 1-[(2-hydroxyethoxy)methyl]-5-)(m--benzyloxy)benzylbarbituric acid ( 37 , BBBA) is the most promising having a K_i value of 1.1 ± 0.2 nM with uridine phosphorylase from human liver. The new inhibitors are easily synthesized and are better inhibitors of human uridine phosphorylase than their uracil counterparts.     

关于“信息熵”分析及其应用的研究

本文用Ｓｈａｎｎｏｎ熵函数的观点及最大离散熵原理，探讨了对随机试验项目的优选问题：即压缩某种“不确定性”试验项目的实施与探索．并通过应用实例的计算，获得了满意的聚类效果．这种方法对于信息资料的数据处理及压缩“不确定性“验项目具有普遍意义．     

金属羰基化合物（CpFe（CO）2）2与金属氧化物表面作用的傅里叶变…

用漫反射红外光谱和光声红外光谱研究了金属羰基化合物（ＣｐＦｅ（ＣＯ）２）２Ｃｐ＝η＾５－Ｃ５Ｈ５与酸性，中性和碱性Ａｌ２Ｏ３及ＴｉＯ２的相互作用，结果表明，在Ａｌ２Ｏ３表面生成的洗生物种类及浓度与Ａｌ２Ｏ３的酸碱度明显相关，在酸性Ａｌ２Ｏ３表面，主要存在衍生物（ＣｐＦｅ（ＣＯ）２Ｆｅ－Ｈ－Ｆｅ（ＣＯ２Ｃｐ）＾＋及少量的ＣｐＦｅ（ＣＯ）２（－Ｏ－）；在中性Ａｌ２Ｏ３表面存在的ＣｐＦｅ（ＣＯ）２（－Ｏ     

α－萘甲酰呋喃甲酰甲烷的合成及谱学性质的研究

本文用Ｃｌａｉｓｅｎ缩合反应合成了未见文献报道的一种新的β－二酮，α－萘甲酰呋喃甲酰甲烷（α－ＮＦＭ），考察了该化合物的红外光谱、质谱及核磁共振氢谱。确定其存在着互变异构。     

胶束荧光法测定维生素B_2含量

维生素B_2(核黄素)为人体内黄酶类辅基的组成部分,参与人体内的生物氧化作用。药典规定其含量测定用分光光度法,文献报道有高效液相色谱法、荧光法等。但因维生素B_2(V_(B2))遇光易分解,尤其在碱性水溶液中,极易变质。其降解产物为感光黄素,二氢核黄素,光化色素等,因此给测定的准确度和灵敏度造成一定的麻烦,为了提     

Grid-search molecular accessible surface algorithm for solving the protein docking problem

An algorithm for solving the protein docking problem is presented. Many tentative dockings are first generated by requiring a hole on the surface of one protein to match a knob on the surface of the other. All the tentative dockings are then applied. The initial configurations thus generated are further optimized. The optimization is facilitated by giving a discrete representation to the protein interior and a double-layer discrete representation to the protein surface. The algorithm presented correctly predicts the association of trypsin with its inhibitor as well as that of the α and β subunits in hemoglobin.     

Analysis of the Coaxial Ridge-Loaded Helical Groove Waveguide

The coaxial ridge-loaded helical groove waveguide is proposed in this paper. As an all-metal slow-wave circuit, it has advantages of good heat dissipation and great size, and thus is suitable for use of millimeter TWT. By means of field theory, the expressions of the dispersion equation and the coupling impedance of the coaxial ridge-loaded helical groove waveguide are obtained. The influence of various circuit dimensions on the dispersion relation and the coupling impedance is investigated by the results of numerical computation.