齿轮强度校核的新方法

实现了渐开线标准圆柱齿轮在AYSYS软件中的参数化设计,模块的二次开发和有限元应力分析,提出了一种齿轮强度校核的新方法,为齿轮的优化设计提供了方法指导。     

导线接触不良火灾事故浅议

根据历年来的火灾统计,电气原因占全部火灾原因的近20%,笔者辖区除农村草垛火灾外,电气原因更是占到了30%以上。其中,导线接触不良引起的火灾占有一定比例。本文通过实例,探讨此类火灾事故的调查,并提醒社会单位注意防范。     

关于带传动中作用力计算的再探讨

<正> 在上文,笔者根据带传动的实际工作情况,对采用自动张紧装置的带传动,进行了理论分析,从而导出带的紧边拉力S_1、松边拉力S_2,以及带传动的有效抗力F的计算公式如下: 下面将对上述计算公式,在其他不同的带传动方式下,作进一步地具体分析与探讨。1.两带轮的中心距固定不变(图1)     

Some open problems in granular matter mechanics

Granular matter is a large assemblage of solid particles, which is fundamentally different from any other type of matters, such as solid and liquid. Most models presented for granular matter are phenomenological and are only suitable for solving engineering problems. Many fundamental mechanical problems remain open. By analyzing characteristics of internal state structure, we propose that granular matter is intrinsically multiscale, i.e. microscale of particle size, mesoscale of force chain, and macroscale of the bulk of granular matter. The correlations among difference scales would be crucial. The mesoscale force chain network is determined by both particle properties and macroscopic boundary conditions. The evolution of the force the chain network contributes to macroscopic mechanical properties of granular matter. In addition, we discuss the drawbacks in simplifying contact forces in the current models, and the difficulties in analyzing the interaction of interstitial fluid in wet granular matter. As an appropriate application of granular matter, debris flow can be studied with granular matter mechanics; meanwhile, debris flow brings more challenges which certainly motivate future studies on granular matter.     

城市污水脱氮除磷新工艺的发展动态

传统的同步脱氮除磷处理工艺存在着诸如泥龄矛盾、碳源竞争等问题,污水进水的低碳源更是给脱氮除磷带来不利影响。文章综述了目前脱氮除磷新工艺的发展动态,介绍了双污泥—诱导结晶工艺、CDPR-BAF工艺、CWSBR工艺和接触氧化—强化混凝组合工艺,并对新型脱氮除磷工艺的发展进行了展望。     

大型水轮机蜗壳座环与水泥基础间的接触问题

本文在采用板壳元、块体元、边界元、伪单元和建立接触点对的基础上,利用分步加载法对蜗壳、座环与水泥基础间的间隙和接触问题进行了有限元分析计算.实例考核证明本文的理论与方法正确、可靠.     

废纸造纸废水处理的工程实例

本文结合工程实例,介绍了废纸造纸工业废水的处理。实例表明,运用混凝气浮与二级生物处理相结合的工艺可行,系统运行稳定,出水水质各项指标均达到《造纸工业水污染物排放标准》（GB3544-2002）中一级排放标准。     

基于液滴轮廓割线的纤维接触角测量方法模拟研究

纤维的润湿性能是制约其在材料领域应用的一个重要因素,开展纤维润湿性能的研究是材料研究领域的一个重要工作。针对纤维润湿性能表征中使用的割线法进行数值模拟分析,考察割线法的可实施性及其测试精度的提升方案。经过分析发现,采用割线对切线进行近似处理时需要保证割线的相对长度(a/z_(max))在0.05到0.07的范围,此时通过优选测量液滴的大小可以将测量误差控制在±2.5°以内。为了方便研究结果的应用,还提出了一种基于液滴轮廓割线的纤维接触角测量方案。研究结果可用于指导一般工程技术人员在没有专门的仪器及软件的情况下开展纤维润湿性能的研究。     

Combined effects of fretting and pollutant particles on the contact resistance of the electrical connectors

Usually, when electrical connectors operate in vibration environments, fretting will be produced at the contact interfaces. In addition, serious environmental pollution particles will affect contact resistance of the connectors. The fretting will worsen the reliability of connectors with the pollutant particles. The combined effects of fretting and quartz particles on the contact resistance of the gold plating connectors are studied with a fretting test system. The results show that the frequencies have obvious effect on the contact resistance. The higher the frequency, the higher the contact resistance is. The quartz particles cause serious wear of gold plating, which make the nickel and copper layer exposed quickly to increase the contact resistance. Especially in high humidity environments, water supply certain adhesion function and make quartz particles easy to insert or cover the contact surfaces, and even cause opening resistance.     

基于容量约束的深空接触图路由算法

为有效利用节点间通信机会保证数据的可靠传输,提出一种基于容量约束的接触图路由算法。一方面,该算法通过比较节点接触的剩余容量和预计容量损耗计算最早到达路径,避免所选路径后续节点没有足够的容量。另一方面,数据包的转发节点数由反馈的链路状态和网络拓扑关系自适应决定,在网络性能和资源消耗中得到平衡。仿真表明,该算法能提高数据包投递率最高27.7%,端到端传输时延最高降低24.5%,有效应对深空恶劣环境的影响。