高能碰撞实验数据非整数分割时的阶乘矩分析

在对相空间用非整数分割作阶乘矩分析时,由二粒子或多粒子关联所引起的非均匀因素的影响必须加以认真考虑.本文对高能碰撞末态粒子的阶乘矩在相空间进行非整数分割时的分析方法进行了仔细研究,建立了一套完整的对非整数分割下阶乘矩的分布进行修正的方法.用NA22实验组的实验数据计算,证明其方法是正确的.     

Time-variable Method for Studying Reaction Rates in a Calorimeter

A novel method for the determination of rate constants of reactions, the time-variable method, is proposed in this paper. The method needs only three time points (t), peak heights () and pre-peak areas (), obtained from the measured thermoanalytical curve. It does not require the thermokinetic reaction to be completed. It utilizes data-processing on a computer to give the rate constants. Four reaction systems, including a first-order reaction, second-order reactions (with equal concentrations and with unequal concentrations) and a third-order reaction, were studied with this method. The method was validated and its theoretical basis was verified by the experimental results.This revised version was published online in November 2005 with corrections to the Cover Date.     

Catalytic, Regiospecific End-Functionalization of Alkanes: Rhenium-Catalyzed Borylation under Photochemical Conditions

Approaching a Holy Grail? A regioselective functionalization of alkanes occurs with commercially available rhenium catalysts and borane reagents under photochemical conditions [Eq. (1)]. Mechanistic studies indicate that the regioselectivity results from a direct thermal reaction of a photochemically generated 16-electron boryl complex with alkane.     

Global Convergence Analysis of Algorithms for Finding Feasible Points in Norm-Relaxed MFD

This paper introduces two new algorithms for finding initial feasible points from initial infeasible points for the recently developed norm-relaxed method of feasible directions (MFD). Their global convergence is analyzed. The theoretical results show that both methods are globally convergent; one of them guarantees finding a feasible point in a finite number of steps. These two methods are very convenient to implement in the norm-relaxed MFD. Numerical experiments are carried out to demonstrate their performance on some classical test problems and to compare them with the traditional method of phase I problems. The numerical results show that the methods proposed in this paper are more effective than the method of phase I problems in the norm-relaxed MFD. Hence, they can be used for finding initial feasible points for other MFD algorithms and other nonlinear programming methods.     

Studies of artificial hydrolytic metalloenzymes: The catalyzed carboxyester hydrolysis by copper(II), zinc(II) and cobalt(II) complexes of the tripod ligand tris(2-benzimidazylmethyl)amine

The hydrolysis kinetics of p-nitrophenyl acetate (NA) catalyzed by Cu^II, Zn^II and Co^II complexes of tris(2-benzimidazylmethyl)amine (NBT) have been studied. The hydrolysis rate is first-order in both metal(II) complex and NA. The second-order rate constants, k_cat are 0.083, 0.241 and 0.285mol^–1Ls^–1 (298K, I = 0.10molL^–1 KNO₃, 0.02molL^–1 tris buffer, 40% MeCN aqueous solution) for Zn–NBT, Co–NBT and Cu–NBT complexes, respectively. The result indicates that the hydrolytic metalloenzyme activity of different metal complexes increases with the electrophilicity of the metal ions and that the complexes, in this paper, constitute that most efficient hydrolytic metalloenzyme models reported to date. An increase in MeCN content in the solution greatly reduces the hydrolytic activity of the nucleophiles.     

Preparation and characterisation of ultrafine amorphous alloy particles

Received: 3 July 1998     

稀土对PVC热稳定机理的光谱研究

稀土ＰＶＣ热稳定剂量是最近才发展起来的一类高效、无毒的稳定体系。本文通过对稀土化合物作用下ＰＶＣ降解的光声光谱和ＰＶＣ傅里叶红外光谱的分析证明,稀土热稳定剂具有优越的稳定性能。稀土作用下ＰＶＣ降解的光声光谱研究显示了稀土热稳定剂比其他热稳定剂具有更好的初色性能;红外光谱研究表明,稀土化合物的稳定作用是由于改变了ＰＶＣ分子的构象,从而增加了ＰＶＣ的稳定性。     

四苯基卟啉及其系列衍生物电子光谱的IDNO／CI研究

运用ＭＮＤＯ计算和群论,优化得到了较满意的中位取代四苯基卟啉的分子构型,并结合ＩＮＤＯ／ＣＩ方法,对四苯基卟啉及其系列衍生物进行了电子结构的研究和电子光谱主要吸收带的指认。对卟啉系列衍生物的取代基效应进行了讨论,得到一些有益的结论。     

固体中反斯托克斯荧光制冷的两种基本机制

研究和论术字激光制冷的两种机制－ＡＳＦＣＳＣ和ＡＳＦＣＥＴ,以及它们的相互关系和应用条件,提出了双机制并行制冷的概念,探讨了双机制并行制冷的可能性。     

1.3μm波长光纤偏振参数自动测试仪

本文介绍一种用于1.3μm波长的光纤偏振参数自动测试仪。它利用光路集成封装和计算机自动控制及信号处理等关键技术,方便、可靠、自动地进行1.3μm光纤及其器件偏振参数的测试,对于消光比为40dB以下的偏振态测量,误差优于0.3dB.