Calculating the energies for Ag(001) twist boundaries utilizing the modified analytical embedded atom method

The unrelaxed energies for Ag(001) twist grain boundaries (GBs) have been calculated using the modified analytical embedded atom method (MAEAM). The results show that, besides zero energy in a perfect crystal (corresponding to the twist angle 0°), the second smallest GB energy corresponds to the twist angle 36.87°. This is consistent with the experimental results. For other twist angles, the GB energies remain nearly constant even for a twist angle as small as 1.94°. Translation parallel to the boundary plane could result in a periodic change in GB energy. Copyright © 2004 John Wiley & Sons, Ltd.     

定标粒子理论的气相色谱保留值方程

以定标粒子理论为基础,通过对溶质、溶剂分子间的相互作用加以系统研究,得到了描述溶质、溶剂分子参量及色谱条件对气相色谱过程中溶质容量因子的影响规律。通过实验证实了溶质容量因子在一定范围内与柱压近似呈线性关系,并验证了容量因子与柱温及加和性物性参量的关系。     

Recoil spectrometry: Ion accelerator based elemental characterisation of surface layers

Recoil Spectrometry covers a group of techniques that are very similar to the well known Rutherford backscattering Spectrometry technique, but with the important difference that one measures the recoiling target atom rather than the projectile ion. This makes it possible to determine both the identity of the recoil and its depth of origin from its energy and velocity, using a suitable detector system. The incident ion is typically high-energy (30–100MeV)³⁵C1,⁸¹Br or¹²⁷I. Low concentrations of light elements such as C, O and N can be profiled in a heavy matrix such as Fe or GaAs. Here we present an overview of mass and energy dispersive recoil Spectrometry and illustrate its successful use in some typical applications.     

化学计量一级站量值传递工作及经验

介绍了国防科工委化学计量一级站为保证化学量值的准确与统一,在计量标准建立、标准物质研制、测量方法研究等方面所做的工作和经验。     

对MDTA中测样品热容量的准恒温法的评述

对用调制差热分析（ＭＤＴＡ）准恒温法测样品热容量的情形进行了讨论。通过结合最基本的热传导定律和ＭＤＴＡ模型，指出了目前国际上测量样品热容量的准恒温法只能得到在所测温度范围内的物质热容量平均值，调制温度的幅度越大或调制频率越高，所得到的热容量数据越平滑。在所测温度范围内样品热容量基本不变时，用ＭＤＴＡ准恒温法较好；但当样品热容量在所测温度范围内有明显变化时，用传统差热分析法（ＤＴＡ）更好一些。     

Proof of the Fukui conjecture via resolution of singularities and related methods. II $$^{\star}$$

The present article is a direct continuation of the first part of this series. We reduce a proof of the Fukui conjecture (concerning the additivity problem of the zero-point vibrational energies of hydrocarbons) to that of a proposition related to the theory of algebraic curves, so that we can focus on the key mechanism of the additivity phenomena. Namely, by establishing what is called the Basic Piecewise Monotone Theorem (BPMT), we reduce a proof of the Fukui conjecture to that of a proposition, called the Local Analyticity Proposition, Version 1 (LAP1), which admits a proof via resolution of singularities. By LAP1, the essential part of the mechanism of the asymptotic linearity phenomena is extracted and is elucidated by using tools from the mathematical theory of algebraic curves, whose language is of vital importance in analyzing the crux of the additivity mechanism. Dedicated to the memory of Prof. Kenichi Fukui (1918–1998).     

The assessment of compliance with legal limits. Part 2. How to consider both type I and type II errors when working in the concentration domain

Considering the uncertainty of measurement when assessing compliance with reference values given in compositional specifications and statutory limits is still a controversial matter. In theory, assessing compliance requires considering both type I (false positive) and type II (false negative) errors. The more the concentration of the analyte in the sample under investigation is close to the allowed concentration limit, the more critical it is to consider both types of errors. This paper describes how this could be done. The matter is discussed in the light of the most recent literature information.     

木材溶液中羟基与异氰酸酯反应的研究

以涂料工业广泛应用的新型助剂二元酸酯 (DBE)为液化试剂 ,盐酸为催化剂 ,将苯甲基化木材溶液化后 ,与不同结构的异氰酸酯反应 .利用FT IR及1 3C NMR分析液化苯甲基木质纤维素与不同结构异氰酸酯得到了聚氨酯树脂 ,证明了木材中羟基可以用来作为聚醚多元醇与异氰酸酯制备聚氨酯材料 .通过准确测量体系中游离的NCO含量 ,从而得出不同结构异氰酸酯与木材溶液中羟基的反应规律 .实验结果表明 ,异氰酸酯的存在大大促进了木材结构中羟基的释放 ,由于不同异氰酸酯的活性不同 ,使得羟基值变化亦不相同 ,其顺序为IPDI>HDI>TDI .为了保证最终的材料性能 ,选择TDI和IPDI作为木材溶液制备聚氨酯树脂的异氰酸酯组份较好     

由酸效应系数计算pH值的新方法

基于酸效应系数αL(H)与溶液酸度的关系,建立了一种由αL(H)手工计算pH值的新方法.该方法无需解高次方程,仅需对lgαL(H)及相关pKa作加减运算、复杂体系也只需增加少量以10为底的乘方运算及常用对数运算即可.因而方法简便,计算误差可预先设置,本文控制不超过5%.