Off-Line Programming of a Robot for Laser Re-Manufacturing

Off-line programming provides an essential link for CAD/CAM. This paper introduced the principle of developing off-line programming system for laser re-manufacturing. Task and information flow of off-line programming for laser re-manufacturing robot was analyzed and the software structure of off-line programming based on commercial CAD software was constructed. The off-line programming system developed in this study includes 3-D solid model design, direct slicing for obtaining path data, graphical simulation of the robot and its workcell, kinematic model of the robot, motion planning, and creation of the control program for manufacturing process. The CAD software was used to design models of robot, workpiece, coaxial nozzle, and workspace. Through the application programming interface provided by the CAD software, the VC++ and ATL were chosen to develop such modules as direct slicing for obtaining path data, path planning, process specification, and control program automatic generation. The FANUC Roboguide software was used to realize graphical simulation. By direct slicing, the position and orientation data of robot end-effector was determined. The results show that the proposed system can be applied in laser re-manufacturing robot for manufacturing operations.     

法布里—泊罗标准具在精密测量中的应用

根据最小二乘法原理,直接对法布里-泊罗标准具产生的干涉条纹进行拟合,在拟合过程中充分考虑了矩阵的病态条件,推导出光波波长与拟合方程系数间的关系.利用干涉条纹数字化方法求出了光波波长,这种方法克服了传统方法难以对准中心(圆心)和干涉条纹发生畸变时不能保证△r2恒为常量的缺陷.利用此方法可实现特殊形状工件的精密测量,提高测量精度.试验结果表明:系统对工件的测量精度可达到10 μm量级,并可实现大规模快速测量.     

英汉语言性别歧视现象的成因及消除

英语和汉语中存在着大量的性别歧视现象,主要是对女性的歧视,它的存在有着深刻的社会经济原因和文化伦理原因。消除它不但需要语言改革,更需要社会革新。     

关于高等职业教育人才培养定位的探讨

随着经济和社会发展,市场对人才的需求呈现出高素质、多类别、多层次的态势。高等职业技术教育只有根据市场需求结合自身发展实际,确定人才培养目标,明确人才培养规格,才能促进自身的科学发展,把学生培养成社会有用之才。     

云南省高校学生参与体育活动的现状调查

运用文献资料、问卷调查及数理统计等研究方法,对云南省5所高校的949名学生进行问卷调查,了解云南省高校学生参与体育活动的现状．研究表明：云南省大学生大多是喜欢体育锻炼的,但没有形成良好的体育习惯;学生体育活动的投入时间少、频率低、随意性大;学生参加体育活动的积极性不高．     

不同挡板开度下静态分离器分离性能数值模拟

为实现对现有静态煤粉分离器及磨煤机系统的实验调整,采用FLUENT软件对MPS磨静态煤粉分离器的分离性能进行了数值模拟,分析了不同挡板开度下分离器内气相速度和不同粒度煤粉体积分数的分布情况。结果表明：分离器的锥形筒部位为强制涡和自由涡两种流动相结合的流动状态,挡板叶片至出口管部位的流动为复杂的三维流动。随着挡板叶片开度减小,分离器对煤粉的分离比率增加,分离能力增强,对较大颗粒的分离作用增强幅度较大,而对较小颗粒的分离作用影响较小。     

Au/TiO2催化剂室温催化燃烧甲醛的研究

采用沉积-沉淀法制备了负载型Au/TiO₂催化剂,以甲醛的催化氧化作为目标反应,采用XRD和TEM对该样品进行了表征并考察了金负载量、沉淀剂种类、反应液pH值、沉积沉淀温度、活化气氛、还原温度及时间等对Au/TiO₂催化甲醛氧化活性的影响。结果表明：1.80%（质量分数）的Au/TiO₂,经过85℃氢气气氛还原,显示了最高的催化甲醛氧化的活性,在30℃、体积空速为15000h^-1,甲醛的体积分数为4.5×10^-4时,可以将50%的甲醛完全转化为H₂O和CO₂。样品中金物种颗粒平均尺寸为4.5nm。     

既有线信号联锁"插入"试验技术

文章主要从施工角度介绍了既有线信号联锁"插入"试验方法,该方法能保证在倒接开通前,控制台--电缆--设备终端联锁关系试验彻底、正确,保证在信号设备倒接开通时正点、顺利,非常适合现在铁路列车运行速度高、运行密度大的既有线路上使用,是以后既有线信号施工试验的发展趋势.     

Blastomere biopsy influences epigenetic reprogramming during early embryo development,which impacts neural development and function in resulting mice

Blastomere biopsy is used in preimplantation genetic diagnosis; however, the long-term implications on the offspring are poorly characterized. We previously reported a high risk of memory defects in adult biopsied mice. Here, we assessed nervous function of aged biopsied mice and further investigated the mechanism of neural impairment after biopsy. We found that aged biopsied mice had poorer spatial learning ability, increased neuron degeneration, and altered expression of proteins involved in neural degeneration or dysfunction in the brain compared to aged control mice. Furthermore, the MeDIP assay indicated a genome-wide low methylation in the brains of adult biopsied mice when compared to the controls, and most of the genes containing differentially methylated loci in promoter regions were associated with neural disorders. When we further compared the genomic DNA methylation profiles of 7.5-days postconception (dpc) embryos between the biopsy and control group, we found the whole genome low methylation in the biopsied group, suggesting that blastomere biopsy was an obstacle to de novo methylation during early embryo development. Further analysis on mRNA profiles of 4.5-dpc embryos indicated that reduced expression of de novo methylation genes in biopsied embryos may impact de novo methylation. In conclusion, we demonstrate an abnormal neural development and function in mice generated after blastomere biopsy. The impaired epigenetic reprogramming during early embryo development may be the latent mechanism contributing to the impairment of the nervous system in the biopsied mice, which results in a hypomethylation status in their brains.     

基于Lyapunov稳定性理论的星型耦合电动机网络的混沌同步

基于Lyapunov稳定性理论和多个体协调控制,通过设计网络中互联电动机节点之间的耦合函数,实现整个星型耦合电动机网络的渐进同步。从理论分析和数值仿真两个方面,证明并验证了该控制策略的有效性。提出的耦合函数结构简单、控制效果良好,对保证电动机传动系统的协调同步运行具有较好的应用参考价值。