液氮制冷低气压试验箱的仿真设计

在采用液氮制冷的低气压试验箱的设计中,用常规工程设计方法计算的降温过程冷负荷过大,从而导致真空系统设计容量过大。本文采用分布参数模型对试验箱低气压条件下降温过程的冷负荷进行了精确仿真模拟,以此作为真空系统容量设计的基础,减小了设计规模,取得了良好的效果。     

国内钛合金近几年学术研究进展

在钛合金研发受到高度重视的同时,相关钛合金的基础研究国内也较重视,取得了较好的成绩,如发展的近β锻造技术、准β锻造技术、三态组织、阻燃机理、低温变形机理、原子与空位的交互作用等等。本文综述了国内钛合金近几年的学术研究进展。     

改进的深度脱木素的硫酸盐蒸煮：第一部分 用硫化钠预处理的桉树硫酸盐蒸煮

用硫化钠水溶液预处理桉树，接着进行改进的深度脱木素硫酸盐蒸煮。结果表明，在１６０℃预处理后脱木素的选择性较常规硫酸盐蒸煮有显著提高，可得到低Ｋａｐｐａ值（约为１０）的浆而没有明显的强度损失。     

宜昌地区下寒武统沉积环境分析

宜昌地区早寒武世除天柱山期(南部和西部称岩家河期)岩性变化较大外,其他依次沉积了以黑色炭质页岩夹灰岩、细碎屑岩、石灰岩、白云岩等为主的岩性组合,反映了中扬子区岩性四分的特点。晚震旦世灯影末期区内是一个东高西低、东北高西南低的浅海沉积区。在此背景上,早寒武世早期(即天柱山期)遭受了短暂而快速海进之后,依次经历了浅海盆地边缘、斜坡带、浅海陆棚及潮坪等沉积环境的缓慢演化,显示了有规律的海退序列。在区内天柱山组、岩家河组及水井沱组等均首次发现了重力流沉积;在水井沱组下部炭质页岩所夹的薄层粉晶云岩中,首次发现了沉积型重晶石富集层。根据区内天柱山期为浅海斜坡带(岩家河期为浅海盆地边缘)、水井沱期为浅海盆地边缘至斜坡带等沉积环境判断。天柱山组(岩家河组)与水井沱组之问应为连续沉积、整合接触。图3表1参7     

液晶显示器生产中的激光退火和缺陷修复

由于在大面积玻璃基底上制备由多层材料构成的高质量薄膜晶体管象元驱动阵列工艺的复杂性，使有源矩阵液晶显示器（AMLCD）的成品率低、价格高。利用激光对AMLCD进行非晶硅薄膜的退火和电路缺陷的修复，可有效的改善AMLCD的性能，提高成品率和降低成本。本文在介绍了激光对非晶硅薄膜退火和电路缺陷修复常用激光器的特性后，讨论了激光对不同类型缺陷修复的原理和过程。最后，分析比较了不同类型激光退火方法的特点。     

非洲爪蟾卵提取物中200nm膜泡与环形片层及核被膜上核孔复合体形成的关系

将ＬａｍｂｄａＤＮＡ引入活化的非洲爪蟾卵提取物中，在由磷酸肌酸与磷酸肌酸激酶构成的ＡＴＰ再生系统的参与下，在这种非细胞体系中能够围绕由ＬａｍｂｄａＤＮＡ诱导形成的染色质重建核被膜结构，同时在染色质外出现类似核被膜结构的环形片层。在这两种膜结构中核孔复合体的形成都与直径２００ｎｍ左右的单层圆形小膜泡密切相关，这些小膜泡可以附着在染色质表面或独立于染色质之外相互融合成扁平囊状的双层膜片层，双层膜进一步融合形成核孔，与此同时，核孔复合体在核孔上完成装配。     

Morphology and Forming Mechanism of Rare Earth Inclusions During Solidification of Steel

ＭｏｒｐｈｏｌｏｇｙａｎｄＦｏｒｍｉｎｇＭｅｃｈａｎｉｓｍｏｆＲａｒｅＥａｒｔｈＩｎｃｌｕｓｉｏｎｓＤｕｒｉｎｇＳｏｌｉｄｉｆｉｃａｔｉｏｎｏｆＳｔｅｅｌ￥ＺｈａｉＱｉ－Ｊｉｅ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｔａｌｌｕｒｇｙ，ＵｎｉｖｅｒｓｉｔｙｏｆＳ...     

Speed–accuracy tradeoff in Fitts’ law tasks—on the equivalency of actual and nominal pointing precision

Pointing tasks in human–computer interaction obey certain speed–accuracy tradeoff rules. In general, the more accurate the task to be accomplished, the longer it takes and vice versa. Fitts’ law models the speed–accuracy tradeoff effect in pointing as imposed by the task parameters, through Fitts’ index of difficulty (I_d) based on the ratio of the nominal movement distance and the size of the target. Operating with different speed or accuracy biases, performers may utilize more or less area than the target specifies, introducing another subjective layer of speed–accuracy tradeoff relative to the task specification. A conventional approach to overcome the impact of the subjective layer of speed–accuracy tradeoff is to use the a posteriori “effective” pointing precision W_e in lieu of the nominal target width W. Such an approach has lacked a theoretical or empirical foundation. This study investigates the nature and the relationship of the two layers of speed–accuracy tradeoff by systematically controlling both I_d and the index of target utilization I_u in a set of four experiments. Their results show that the impacts of the two layers of speed–accuracy tradeoff are not fundamentally equivalent. The use of W_e could indeed compensate for the difference in target utilization, but not completely. More logical Fitts’ law parameter estimates can be obtained by the W_e adjustment, although its use also lowers the correlation between pointing time and the index of difficulty. The study also shows the complex interaction effect between I_d and I_u, suggesting that a simple and complete model accommodating both layers of speed–accuracy tradeoff may not exist.     

基于Rough集的遥感影像增强方法研究

通过对Rough集理论特点和遥感影像信息的不确定特性分析,基于对Rough集理论的不可分辨关系、近似集合和分类概念的分析,研究实现了一种保护图像边缘的遥感图像滤波和增强的算法,并通过实验证明了该算法的效果和有效性.