高职院校学生退学现象探析

该文从客观与主观两方面,分别探讨各年级学生的特点,分析了高职院校学生退学的主要原因,并提出了相应的措施.     

Modification of the rib operon derived from Bacillus subtilis and its expression in Escherichia coli

A riboflavin operon （rib operon） derived from Bacillus subtilis 368 was modified on structure and the resulting operons were expressed in various strains of Escherichia coli. The results showed that the optimization of the rib operon and the host strain used for expression are two main factors affecting the riboflavin production. Replacing the promoterl and rfn box of the rib operon with a strong constructive promoter spol drastically increased the expression of the rib genes. When E. coli JM109 was used as the host strain, the highest riboflavin production reached 95.3μg/mL （about eight times higher than that of the unmodified r/b operon）. In addition, when tetracycline （20 μg/mL） was used as the selective pressure, compared with the ampicillin resistant transformants, a higher riboflavin yield was obtained in tetracycline resistant host strain.     

ECC点乘运算在网络并行实现中的装箱问题

基于网络并行计算,提出椭圆曲线公钥密码体制点乘运算在网络并行环境中实现的算法,详细分析了并行环境中的装箱问题,建立了并行子任务分派的数学模型,并对模型的采用贪心策略的FirstFit算法就行求解,解决了网络并行计算环境下的ECC点乘并行算法实现的任务分配问题.     

基于本体的个人信息构建方法及共享研究

讨论了本体的基本概念,个人本体Personal Ontology的形式化表达方法及本体元素之间的关系。在此基础上提出了个人本体模型的基本架构及其UML建模方法。并且讨论在大学校园里面,协商代理和个人代理通过Personal Ontology进行知识分享的解决方案。最后给出将本体模型映射到实际编程环境和持久存储模式的方法。     

矩阵的广义逆的正交反向传播算法

利用多层前向神经网络研究了矩阵广义逆的计算，但算法采用正交反向传播算法，利用ＯＢＰＡ算法，经过有限次迭代即可得到矩阵广义逆的精确解。     

基于RBF神经网络的一类非线性系统模糊自适应控制

针对一类非线性不确定系统,基于ＲＢＦ神经网络,结合模糊滑模控制提出了一种自适应控制方法。根据Ｌｙａｐｕｎｏｖ稳定性理论设计ＲＢＦ网络和模糊滑模补偿控制器的参数。     

红莲型水稻不育系与保持系线粒体DNA酶切分析

为研究红莲型水稻细胞质雄性不育的分子基础，我们提取纯化了红莲型水稻丛广４１Ａ和丛广４１Ｂ的线粒体ＤＮＡ，采用限制性内切酶酶切片段长度多态性（ＲＦＬＰ）方法比较了红莲型不育系和保持系线粒体ＤＮＡ酶切图谱，发现两者之间存在一定的差异，部分支持了细胞质雄性不育与线粒体ＤＮＡ有关的结论。     

Mapping of the nuclear fertility restorer gene for HL cytoplasmic male sterility in rice using microsatellite markers

Bulked segregant analysis (BSA) of a BC, population derived from Congguang 41A//Miyang 23/Congguang 41B was used to map the nuclear fertility restorer gene for Honglian (HL) cytoplasmic male sterility. One hundred and fifty-nine microsatellite primer pairs were screened for polymorphisms between the parents and between two bulks representing fertile and sterile plants. One microsatellite marker RM258 produced polymorphic products. The nuclear fertility restorer gene for HL cytoplasmic male sterility was mapped on chromosome 10, 7.8cM from RM258. The restorer gene may be clustered on chromosome.     

一类动力系统dy/dx=x_1/P_3(x,y)的全局结构

本文考察了以抛物线ｙ＝ａｘ２＋β为特解的一类三次系统的全局结构。首先得出其等价系统，然后通过对其奇点的分析及应用Ｄｕｌａｃ—函数证明了这一系统在全平面上无极限环。