δ－Al_2O_3纤维／Al－12Si复合材料室温拉伸强度分析

对δ－Ａｌ２Ｏ３纤维／Ａｌ－１２Ｓｉ复合材料室温拉伸强度的分析表明，在实验条件下该复合材料存在δ－Ａｌ２Ｏ３纤维的最小体积分数Ｖｍｉｎ和临界体积分数Ｖｃｒｉｔ，并求出其基体强度σ＇ｍ和室温强度σｃ－δ－Ａｌ２Ｏ３纤维体积分数Ｖｆ直线方程及纤维的临界长度ｌｃ和复合材料的剪切应力τｉ．确定复合材料的ＲＯＭ预测曲线，应首先判断σ＇ｍ是否等于未增强合金的强度σｕｍ才能得出正确的结论     

ANALYSIS ON ROOM TEMPERATURE TENSILE STRENGTH OF δ-Al_2O_3, FIBER / Al-12Si COMPOSITE

对δ－Ａｌ２Ｏ３纤维／Ａｌ－１２Ｓｉ复合材料室温拉伸强度的分析表明，在实验条件下该复合材料存在δ－Ａｌ２Ｏ３纤维的最小体积分数Ｖｍｉｎ和临界体积分数Ｖｃｒｉｔ，并求出其基体强度δｍ和室温强度σｃ－δ－Ａｌ２Ｏ３纤维体积分数Ｖｆ直线方程及纤维的临界长度ｌｃ和复合材料的剪切应力τＰ确定复合材料的ＲＯＭ预测曲线，应首先判断σｍ是否等于未增强合金的强度σｕｍ才能得出正确的结论。     

Zero aliasing ROM BIST

Signature analyzers are very efficient output response compactors for BIST design. The only limitation of signature analysis is the fault coverage reduction (aliasing) due to the information loss inherent to any data compaction. In this article, in order to increase the effectiveness of ROM BIST, we take advantage from the simplicity of the error patterns generated by ROMs and we show that aliasing free signature analysis can be achieved in ROM BIST.This work was performed when the author was on leave from Minsk Radio Engineering Institute, Computer Department, Belorus.     

无双线性对的无证书安全签密方案

已有的无双线性对的无证书签密方案,大都存在着机密性漏洞和签名选择性伪造问题。针对此问题,基于有限乘法交换群上的离散对数难题,提出一种无双线性对的无证书签密方案,并进行了安全分析和证明。指出采用随机预言模型的证明方法可能忽略不解决DL难题时对签密方案的攻击,不能证明破解签密方案的难度与解决DL难题相等价。通过对参数的数学分析,证明了破解本签密方案的必要条件是解决DL难题,不存在不解决DL难题攻击本签密方案的多项式时间算法。与已知所有方案相比,所提方案安全性更高。     

ZA22／Al2O3（F）复合材料室温拉伸强度的模拟研究

采用挤压法制备ＺＡ２２／Ａｌ２Ｏ３（Ｆ）复合材料，分别采用强度混合准则和神经网络模型研究了含Ｃｅ与不含Ｃｅ的ＺＡ２２／Ａｌ２Ｏ３（Ｆ）室温拉伸强度随短纤维体积分数Ｖｆ的变化情况，结果表明：强度混合准则能有效地预测复合材料的两个重要体积分数即最小体积分数Ｖｍｉｎ和临界体积分数Ｖｃｒｉｔ；而神经网络不仅能较准确地预测Ｖｍｉｎ和Ｖｃｒｉｔ，并且能够较好地描述复合材料强度随Ｖｆ的变化规律。     

复杂电磁干扰环境下的C6000 DSP自举方法

对TMS320C620X／670XDSP的存储结构和特点进行分析,采用分两次生成ROM文件的方式实现TMS320C620X／670XDSP自举,并阐述了该自举方法的关键过程。通过该自举方法,程序在片内RAM中执行,预置参数和常量从外部ROM中读取。结合软件三模冗余,该自举方法可以防止复杂电磁干扰环境下单粒子翻转效应。该方法已得到实际应用,行之有效。     

基于模块化的PGI ROM研究

介绍一种PCI ROM的模块化结构,探讨DOS系统下的.COM文件的特点,介绍UPX压缩软件的特点,研究UPX文件的头格式.针对PCIKOM容量的限制,提出一种用UPX方式压缩,COM文件并存储在PCI ROM中的广法,给出调用UPX文件的代码示例.     

基于ARM的加密锁设计

介绍一种基于ARM的密码锁,它对系统的硬件设计和软件设计进行详细的描述。硬件方面,系统采用LPC2114为微控制器,CSI24WCO2为E^2PROM。LPC2114通过I^2C总线与CS124WCO2通信以实现系统功能。软件方面,系统主要包括加密和解密两部分。     

Effects of military load carriage on kinematics of gait

Manual load carriage is a universal activity and an inevitable part of the daily schedule of a soldier. Indian Infantry soldiers carry loads on the waist, back, shoulders and in the hands for a marching order. There is no reported study on the effects of load on gait in this population. It is important to evaluate their kinematic responses to existing load carriage operations and to provide guidelines towards the future design of heavy military backpacks (BPs) for optimising soldiers' performance. Kinematic changes of gait parameters in healthy male infantry soldiers whilst carrying no load (NL) and military loads of 4.2–17.5 kg (6.5–27.2% body weight) were investigated. All comparisons were conducted at a self-selected speed. Soldier characteristics were: mean (SD) age 23.3 (2.6) years; height 172.0 (3.8) cm; weight 64.3 (7.4) kg. Walk trials were collected using a 3-D Motion Analysis System. Results were subjected to one-way ANOVA followed by Dunnett post hoc test. There were increases in step length, stride length, cadence and midstance with the addition of a load compared to NL. These findings were resultant of an adaptive phenomenon within the individual to counterbalance load effect along with changes in speed. Ankle and hip ranges of motion (ROM) were significant. The ankle was more dorsiflexed, the knee and hip were more flexed during foot strike and helped in absorption of the load. The trunk showed more forward leaning with the addition of a load to adjust the centre of mass of the body and BP system back to the NL condition. Significant increases in ankle and hip ROM and trunk forward inclination (≥10°) with lighter loads, such as a BP (10.7 kg), BP with rifle (14.9 kg) and BP with a light machine gun (17.5 kg), may cause joint injuries. It is concluded that the existing BP needs design improvisation specifically for use in low intensity conflict environments.

Statement of Relevance:The present study evaluates spatial, temporal and angular changes at trunk and limb joints during military load carriage of relatively lighter magnitude. Studies on similar aspects on the specific population are limited. These data can be used for optimising load carriage and designing ensembles, especially a heavy BP, for military operations.     

Wrist discomfort levels for combined movements at constant force and repetition rate

Sixteen male subjects each performed a repetitive, downwards, non-prehensile wrist exertion task with the arm pronated, at a rate of 15 times per minute and with a force of 10N?±?1N in 49 combinations of flexion/extension and radial/ulnar deviation to 0%, 18%, 38% and 55% of the Range of Motion (ROM) for 5 min each. The dependent measure was discomfort measured on a 100 mm visual analogue scale and for most of the analyses these were standardized by using the min?-?max procedure of <citeref rid="b20">Gescheider (1988)</citeref>. These Standardised Discomfort Levels (SDLs) were fitted to mathematical equations from which iso-discomfort contours were derived relative to the percentages of flexion/extension and radial/ulnar-deviation ROM used. The lowest standardized discomfort was found for the neutral wrist posture, followed by 18% extension with neutral radial/ulmar deviation. The results reveal interesting features of the processes involved and provide useful avenues for further research.