40Cr钢复合热处理强韧化

用光学及电子显微镜(SEM.TEM)观察不同热处理的40Cr 钢的冲击及断裂韧性断口、及金相组织,阐明其间相互关系;断口结构可反映断裂特征,组织情况;细化晶粒提高强度、塑性和冲击韧性,但却减少脆断的特性距离 l 因而降低 K_(1c)模;减少碳(杂质)偏聚而使其呈较均匀地分布,从而减少可诱发塑坑的较粗大的碳(杂质)化合物的析出,即增加塑坑的间距 di 以及增加塑断组成物。从而都可增加断裂临界应变 ef,都可以提高 K_(1c)40Cr 复合热处理既靠先超高温淬、回火以减少碳(杂质)偏聚,改善其分布,以反增加位错马氏体从而提高 K_(1c),也靠后淬、回火细化晶粒而提高强度、塑性和冲击韧性,各自发挥长处达到强韧化。     

电子封装用金属基复合材料的制备

分析了电子封装用金属基复合材料的性能特点及其对制备工艺的要求，在此基础上论述了该种材料的各种制备工艺的特点及发展现状。     

Comments on “Equivalence of characterizations of fixed models”

In this note we present a proof to the conjecture given in the above paper, and therefore establish the equivalence of characterizations of fixed modes for the general case.     

一种光时分制交换时隙分配计算算法

介绍了一种专为时分复用系统设计的时院分配计算算法。这种算法中主要用到的技术是从一个话务矩阵的各行选出一个区别代表的系统方法。对于任何话务矩阵，这种算法的分配效率都能达到１００％，所产生的模式矩阵个数最多为ｎ２－２ｎ＋２个（对于ｎ×ｎ矩阵）。     

Bright Blue Light—emitting Diodes Based on a Novel Fluorescent Dye Containing Heterocyclic Groups

Novel molecular material ,1-benzothiazoly-3-pheny1-pyrazoline (BTPP) was found to function as bright blue light emitting dye in organic electroluminescent device, and its optical and electric characteristics were investigated. This heterovyclic compound exhibited good characteristics of blue photoluminescence and electroluminescence,which had the emission peak at 450nm .The single layer light-emitting devices using BTPP as light -emitting material dispersed in poly(N-vinylcarbazole)(PVK) and double layer ones using PBD as hole block layer above the light-emitting layer were fabricated using conventional spin-casting and vaccum vapour deposition methods. The introduction of PBD has enhanced electron injection and luminance efficiency, compared with the single layer LEDs.     

Chemical Interactions in Diboride-Reinforced Oxide-Matrix Composites

Thermochemical analyses of interfacial reactions in titanium, zirconium, and hafnium diboride reinforced oxidematrix composites have been carried out to evaluate the chemical compatibility. The chemical reactivity of these diborides with oxygen and the high volatility of B₂O₃( l ) at reduced oxygen pressures are concerns during processing and operating conditions. The thermochemical stability and the vaporization behavior of B₂O₃( l ) are discussed in terms of partial pressures of dominant gaseous species of the boron-oxygen system at 1700 and 2300 K. The TiB₂/ZrO₂ and TiB₂/HfO₂ systems are thermodynamically stable in a limited oxygen pressure range. The TiB₂/Al₂O₃ system is stable, but the reactions in this system may apparently be accompanied by formation of gaseous products (B₂O₃, AlO, Al₂O, and lower boron oxides) in the presence of elemental oxygen. These thermochemical considerations are very useful in evaluating the effectiveness of oxides as diffusion barrier coatings on diboride reinforcements.     

预测控制算法的统一格式及其在电加热炉的应用

本文根据常用的两类预测控制算法推出一种新型预测控制算法。并将其应用于一双输入/双输出的力学持久机电加热炉的温度控制系统上,获得了满意的结果:控温精度为±1.5℃/300℃,且适用于非最小相位系统。     

示例学习的扩张矩阵理论

本文提出示例学习的一种计算理论,扩张矩阵论.根据这个理论,示例学习中一些主要最优化问题被证明是NP难题,并给出这些难题的近似解法及下界的估计.     

On the mechanical behavior of aluminum alloys reinforced by long or short alumina fibers or SiC whiskers

This study was initiated to examine the dispersion of longitudinal and transverse waves in metal matrix composites in order to obtain the dynamic elastic modulus and to evaluate various models for predicting the composite's macroscopic elastic constants from the properties of its constituents. The materials chosen for this investigation were alumina continuous fibers on the one hand and alumina and SiC short fibers on the other hand, all embedded in an aluminum alloy matrix. In addition, some indications have been obtained experimentally for the acoustoelastic effect in the composite.     

点阵汉字无级变倍算法

本文给出了由一种汉字字库得到任意大小汉字点阵的算法.该算法能对任意二值点阵图像进行放大平滑.简单放大是按字节进行运算,速度快;最佳平滑操作不是对简单放大后的点阵按位操作,而是根据原点阵的特性,在需要平滑的地方进行操作,需操作的位数不会超过图像总点数的5％.用该方法输出的汉字质量和速度都令人满意.