Clones identification of Sequoia sempervirens (D. Don) Endl. in Chile by using PCR-RAPDs technique

A protocol of polymerase chain reaction-random amplified polymorphic DNAs (PCR-RAPDs) was established to analyse the gene diversity and genotype identification for clones of Sequoia sempervirens (D. Don) Endl. in Chile. Ten (out of 34) clones from introduction trial located in Voipir-Villarrica, Chile, were studied. The PCR-RAPDs technique and a modified hexadecyltrimethylammonium bromide (CTAB) protocol were used for genomic DNA extraction. The PCR tests were carried out employing 10-mer random primers. The amplification products were detected by electrophoresis in agarose gels. Forty nine polymorphic bands were obtained with the selected primers (BG04, BF07, BF12, BF13, and BF14) and were ordered according to their molecular size. The genetic similarity between samples was calculated by the Jaccard index and a dendrogram was constructed using a cluster analysis of unweighted pair group method using arithmetic averages (UPGMA). Of the primers tested, 5 (out of 60) RAPD primers were selected for their reproducibility and high polymorphism. A total of 49 polymorphic RAPD bands were detected out of 252 bands. The genetic similarity analysis demonstrates an extensive genetic variability between the tested clones and the dendrogram depicts the genetic relationships among the clones, suggesting a geographic relationship. The results indicate that the RAPD markers permitted the identification of the assayed clones, although they are derived from the same geographic origin. Project (No. CONICYT-FONDEF PROYECT D01 I 1008) supported by the National Commission of Science and Research of Chile     

New method of improving parts accuracy by adding heat balance support in selective laser sintering

In order to improve parts accuracy, a method of adding heat balance support （HBS） was proposed, and the detailed algorithm for generating HBS was developed. A number of experiments and a comparison between similar softwares, showed that the algorithm is efficient and feasible. Moreover, different features of riBS were studied for different kinds of materials, such as PS and nylon. The research findings indicate that automatically adding HBS can significantly improve the accuracy of the parts, and that the algorithm for generating HBS is efficient and precise.     

随机性模型下(s,S)订货策略在企业库存中的应用分析

现代企业在库存管理上主要采用两种模型,即确定性决策模型和随机性决策模型。通过对某拥有军用和民用两种产品的轮胎企业的调查研究,设计了适合其库存管理的决策模型。针对其民用轮胎产品需求的特性,结合企业数月实际的需求量,通过确定性模型推导出一般的随机性模型。仿真实验结果显示,(s,S)模型比EOQ模型有成本更低的优异性。     

基于CCD的回波信号图预处理软件设计与实现

随着光散射法测量PM2.5颗粒物浓度技术的发展,该技术成为测量大气PM2.5浓度的主要手段之一。散射激光雷达接收到的信号为回波信号图,通过建立回波信号图灰度值与PM2.5浓度的关系模型,实现对颗粒物浓度的测量。该技术需要对回波信号图进行预处理并提取散射信号,为了实现一种高性能、可实时测量的回波信号图预处理系统,设计一款基于Delphi7语言的实时图像处理软件。该软件通过对内存分配双缓冲区域、设置采集频率以及图像裁剪等方法,提高图片的采集与处理速率。实验结果表明,该软件操作简单、运行稳定且可扩展性较强。     

基于Struts2结构的在线考试系统设计与实现

基于Struts2和J2EE技术框架,结合MySQL数据库,设计并实现了一个基于B/S架构的在线考试系统,重点阐述了用户答题模块的设计,并提出了一种系统随机出题的方法。     

激光脉冲测量技术解析

介绍了超短激光脉冲技术的基本原理和产生过程,分析了超短脉冲的压缩技术以及近年来比较常用的几种测量技术直接测量法和间接测量法,重点研究了基于二次谐波的频率分辨光开关法（FROG）的脉冲测量法,以及这种测量方法的优缺点,并与自参考光谱相位相干电场重建法（缩写为SPIDER）进行了比较,分析了两种测量法各自的优缺点.     

增益开关激光脉冲时基抖动的测量方法

分析了增益开关激光脉冲抖动产生的原因及其分类.系统介绍了取样示波器法、相位噪声法、谐波分析法和互相关法等测量脉冲抖动的方法,并总结了它们的优缺点及适用范围.     

激光微细加工在电子工业中的应用

从电子工业的角度出发,介绍激光微细加工的应用,包括:激光打标、细导线剥离、微透镜列阵、激光光刻、激光表面改性等,并综述了它们的研究现状和未来发展趋势。     

计算机数值模拟实验设计Ⅱ——强激光脉冲对低密度等离子体通道中电子的共振加速

本文以计算机数值模拟方法,设计了一个新的近代物理实验:研究强激光脉冲对低密度等离子体通道中电子的共振加速。     

浅谈《概率论与随机过程》课程教学

《概率论与随机过程》是电子信息类专业的一门重要的学科基础课,该课程不仅具有较强的理论性,还具有较强的实践性。因此在课程教学中,如何有效组织课程内容,提高学生学习兴趣,进而开拓学生思维,是本课程教师应该深思的问题。文章结合作者的教学经验,对该课程的教学方法进行了总结和探索。