激光相变硬化性能与工艺参数关系的数学模型

用回归正文分析的方法．建立了中碳结构钢、碳素工具钢和合金结构钢的激光相变硬化性能与工艺参数间关系的数学模型。分析了回归力程的显著性并预测了各硬化指标的精度。     

内燃机车曲轴中频淬火过程的数值模拟

借助 ANSYS大型有限元分析软件 ,实现了 16 V2 4 0曲轴淬火过程的计算机模拟 ,模拟结果可直观地显示出任一时刻曲轴表面及内部的温度分布、冷却曲线以及淬火结束后的残余应力分布 ,并能预测淬硬层深度。同时对比了轴颈内圆角处进行淬火和不进行淬火两种工艺的效果 ,为现场提供了用虚拟现实方法详尽分析和研究淬火工艺的工具。     

章江水闸安全论证

结合江西赣州章江水闸安全鉴定工作,阐明了水闸安全鉴定基本内容和方法,并参照有关规范和标准作出了安全分析评价.     

汉白玉废料制备球形纳米碳酸钙的研究

将汉白玉废料通过高温煅烧分解得到氧化钙,再用氯化铵循环液溶解氧化钙制得碱性氯化钙溶液,除去其中的Mg、Fe等杂质得到氯化钙精制溶液,利用化学方法合成得到碳酸钙粉体.用X射线衍射(XRD)、扫描电镜(SEM)及激光粒度分析仪、白度仪对碳酸钙产品的晶相组成、形貌、粒度分布、白度及化学组成进行了分析,所得产品为纯度达98.5%以上、白度达97%以上、平均粒度为80nm左右的球形纳米级碳酸钙.并对碳化反应速率及合成球形纳米碳酸钙的影响因素进行了分析.实验中循环使用NH4Cl,氨的排放量小,减少了环境污染.     

A Survey of E-Commerce Security

E-commerce is a very active field of Internet research. A very important aspect of e-commerce is its security. Because of the variety of e-commerce applications, many security policies, protocols and techniques are involved in the deployment of the security. The related standards and protocols of e-commerce are studied in this paper. The general model of e-commerce security is set forth. In this model, two most important e-commerce protocols including secure sockets layer (SSL) and secure electronic transaction (SET) are analyzed. The open problems and new trends of e-commerce security are presented.     

光通信技术讲座--(五):WDM系统光节点器件

介绍WDM系统光节点所用到的器件,如波长转换器、光分插复用器及其使用的光隔离器和光环形器.     

^125I,^131I诱发小鼠精子畸形发生率比较

本文选用 ICR 雄性小鼠,经腹腔分别注射不同剂量的~(125)I 及~(131)I,观察并比较它们对小鼠精子畸形发生率的影响及染毒后睾丸中放射性活度的变化。实验结果表明:(1)~(125)I 染毒后4—5周,0、185、370和555 kBq 各组精子畸形发生率分别为9.00‰、9.57‰、11.6‰及13.9‰;~(131)I 染毒后4—5周,上述各组精子畸形发生率分别为8.50‰、12.5‰、14.7‰和15.5‰;在相同注入量下,~(125)I 与~(131)I 诱发小鼠精子畸形发生率的差异各组均不显著(X~2检验,p>0.05)。(2)~(125)I、~(131)I 染毒后2h 至7天内,两者在睾丸中的放射性活度及变化规律相似,即在染毒后2h 达最高值,每克睾丸中~(125)I 和~(131)I 的放射性活度分别占初始注入量(370 kBq)的0.72％和0.50％,然后迅速下降,至一周时,仅分别占初始注入量的0.035％和0.011％。     

具有常数收获率的竞争—扩散问题解的性态

讨论牛曼边界条件下具有常数收获率的竞争—扩散问题解的性态,得到当收获率满足当条件时,种群u将在有限时刻被消灭。     

Radiation of millimeter waves from NRD leaky wave antennas withtapered transition and tuning aperture

The radiation of millimeter waves from the nonradiative dielectric (NRD) leaky wave antennas with the tapered transition and the tuning aperture is investigated. An accurate theory for the leakage constant and the phase constant of the antennas is presented, which is based on the generalized scattering parameters considering the higher-order mode interactions at the discontinuities. The associated transverse equivalent network involves the characterization of the mode couplings at two air-to-dielectric interfaces, the coupled mode analysis of the tapered transition, and the calculation of the radiation fields at the tuning aperture via the extended spectral domain approach. The interesting behavior of the present modified configuration of NRD leaky wave antennas is illustrated by typical examples. The validity of the theory is confirmed by the comparison of the theoretical results with experimental data for the limiting cases     

燃气管网模拟分析软件的开发与应用

介绍了以牛顿节点法模型为基础、应用VB语言开发管网分析软件的思路和方法,开发的软件具有实用性、稳定性和易操作性.结合实例,说明了软件在天然气转换方案选择、事故工况分析等领域的应用.