背越式跳高教学中应用多媒体技术的实践与探讨

在背越式跳高教学中实行多媒体组合教学 ,改进传统单一的教学方式 ,加深了学生对技术本质特征的理解 ,经教学实验对比 ,教学效果明显提高 .并具体分析探讨了开展多媒体教学的优越性和重要性     

HoBa2Cu3Ox的超导电性

通过交流磁化率和X-ray衍射分析，对用固态反应法制备的HoBa2Cu3Ox超导体的超导电性进行了研究．实验结果表明：随淬火温度的升高．由正交相(123相)向介于正交和四方相之间的过渡相变化；超导转变温度Tc(0)(零场下)从90K降到38．5K；交流磁化率虚部峰值温Tp(H)随附加直流磁场的增加而降低，Tp与Hdc之间的关系偏离[1一Tp(H)／丁(0)]∞H^2/3规律．     

构造Hadamard差集的新途径

利用环上的特殊非线性函数,提出构造参数为(4q\+2,q(2q-1),q(q-1))的Hadamard差集的新途径.     

霍耳效应实验分析

对霍耳效应测量磁感应强度的实验原理作了分析,讨论了外界定向干扰磁场对实验的影响、指出在实验教学中,相邻霍耳效应测量仪摆放距离宜大于等于2.5m才能忽略相互干扰.     

互补问题中Gauss-Newton方法全局收敛性的推广(英文)

研究了由Subramamian为求解互补问题提出的阻尼Gauss-Newton方法的收敛性质，在较弱的条件下，给出了一个全局收敛效果，这个结果是Subramanian PK (1993)和（1997）中相应结果的一个推广。     

利用二次贝齐尔函数的一维优化算法

本文利用贝齐尔函数良好的保型性质,将它作为拟合函数,构造了一个一维优化算法。数值实验表明,对于高度非线性的目标函数,新算法具有很强的适应性,比同类算法更有效。     

The genetic diversity of cen-tral and peripheral popula-tions of ratlike hamster(Cricetulus triton)

The impact of habitat fragmentation and isolation on the genetic diversity of populations has attracted much attention in studies of meta-population and conservation biology. In this work, using the randomly amplified polymorphic DNA (RAPD) technique, we studied the genetic diversity of central, peripheral and peninsular populations of ratlike hamster, which were collected in five locations of the North China Plain and its surrounding areas, in 1999. The study revealed that, ⅰ) the genetic diversity of central population of Raoyang County＞the sub-central populations of Gu'an County and Taikang County＞the peripheral population of Shunyi District＞the peninsular population of Mentougou District; ⅱ) the genetic diversities of the five populations were positively correlated to the nearest distances to the peripheral line of population distribution; ⅲ) there were significant differences of gene frequencies of some RAPD fragments among the five populations. More RAPD fragments disappeared in peripheral populations than in central or sub-central populations. The frequencies of two RAPD fragments were correlated to the latitude. This study clearly indicated that the variation of the genetic diversities of the five populations was caused by edge effect and frag- mentation through the enhanced inbreeding and genetic drift, and thus supported the view that habitat fragmentation and related edge effect reduce the population genetic diversity.     

用非线性反馈控制混沌Roessler系统到达任意目标

本文设计了识别不确定Roessler系统未知参数的观测器，提出了控制Roessler系统中混沌的非线性反馈控制策略。数值模拟结果表明：观测器可以有效地标识未知参数；选取不同的目标参数，既可以使Roessler系统稳定在不同周期轨道上，也可以稳定在任意目标点上。