一个Markov转移概率函数的确定

利用柯尔莫哥洛夫向前方程计算了电话呼唤次数的随机过程的转移概率函数。     

PWM控制变阻调速系统

分析了PWM的调整方式，利用绕线式电机和串电阻调速的原理，提出了一种结构简单、功率强的变阻调速系统。     

集成电路高精度高速度在线电阻检测

本文提出的具有粗、精测双回路的测试系统,可兼顾电阻在线检测过程中的高精度与高速度问题。该系统各器件间的信息交换满足IEEE-488标准。     

基于航速修正处理的单舰被动定位算法

提出一种基于航速修正处理的单舰被动定位算法，在修正增益推广卡尔曼滤波器的基础上，该算法把运动目标舰艇的航道约束当作输出为0的增加的观测数据加入到测量方程，约束的强度由约束条件的噪声方差确定。提出一种规避因子，用来约束目标状态方程中的航速，基本思想是根据当前估计的目标位置和航速，估计了一个针航行到陆地岛礁或即将航行到陆地岛礁时，用规避因子矩阵来修正航速的方向和大小，避免了出现目标航行到陆地岛礁的情况。计算机模拟结果表明，航速修正处理后不会出现穿越陆地岛礁的运动舰艇航透，同时还能提高对海上运动舰艇辐射源的被动定位精度。     

甘油—乙醇混合液超声性质研究

测量了不同浓度的甘油、乙醇混合液的声速和密度,计算了超额绝热压缩系数.结果表明,在整个浓度范围内,甘油和乙醇之间存在着强烈的分子相互作用.     

Cutting tool materials for high speed machining

High speed machining (HSM) is one of the emerging cutting processes, which is machining at a speed significantly higher than the speed commonly in use on the shop floor. In the last twenty years, high speed machining has received great attentions as a technological solution for high productivity in manufacturing. This article reviews the developments of tool materials in high speed machining operations, and the properties, applications and prospective developments of tool materials in HSM are also presented.     

恒压供水变频控制系统

变频控制供水系统先进的工作原理及实施方法,克服了传统的供水系统浪费较大、稳定精度较差的缺点,可以取得较大的经济效益。详细论述了这种系统的节能工作原理及实现方法。     

Evolutionary and ecological implications of cardenolide sequestration in the monarch butterfly

Summary Monarch butterflies sequester cardenolides from their larval host plants in the milkweed genusAsclepias for use in defense against predation. Of 108Asclepias species in North America, monarchs are known to feed as larvae on 27. Research on 11 of these has shown that monarchs sequester cardenolides most effectively, to an asymptote of approximately 350 g/0.1 g dry butterfly, from plants with intermediate cardenolide contents rather than from those with very high or very low cardenolide contents. SinceAsclepias host plant species are distributed widely in space and time across the continent, monarchs exploit them by migration between breeding and overwintering areas. After overwintering in central Mexico, spring migrants east of the Rocky Mountains exploit three predominantAsclepias species in the southern USA that have moderately high cardenolide contents. Monarchs sequester cardenolides very effectively from these species. First generation butterflies are thus well protected against predators and continue the migration north. Across the northern USA and southern Canada most summer breeding occurs on a fourthAsclepias species and in autumn most of these monarchs migrate back to Mexican overwintering sites. The ecological implications of this cycle of cardenolide sequestration for the evolution of monarch migration are discussed.     

含铝高速钢中奥氏体非均匀长大的机制

M2AI和M2高速钢经一次和二次淬火后,奥氏体晶粒和未溶碳化物的定量研究表明,在高温r/f比值相同的条件下,由于淬火前原始组织的差别,可发生正常(均匀)和异常(非均匀)两类长大。根据异常粗晶形成初期的组织观察,提出了“连续-非连续”再结晶模式和“合并—推移”式的生长机制。提出了减轻或消除M2AI钢混晶的工艺原则。     

“分区教学法”在速滑课中的运用

本文根据速滑课的教学特点,对速滑课组织教法的选择和运用进行了深入的研究和探讨,通过多种组织教法的实验和对比,认为“分区教学法”是速滑课组织教法的最佳选择。“分区教学法”有利于学生掌握和提高滑冰技术,有利于场地的合理使用,减少伤害事故的发生,使冰场上的教学秩序井然,有利于因材施教,使教师的主导作用得到充分的发挥,并能激励学生向明确的目标努力,增强学习的信心。