衔铁零件挤压成形工艺理论与实验研究

继电器衔铁零件是一种非对称的Z形薄壁纯铁件,其挤压工艺的凹模设计是一个难点。在构造出坯料和成型零部件的有限元模型的基础上,利用DERORM-3D软件对其进行有限元分析,得到了最优模角和最佳工作带长度,优化型腔结构,为挤压模具结构设计提供了坚实的依据。实验研究结果表明,数值模拟分析准确,模具结构设计合理。     

CONCURRENT SORPTION OF HEAVY METAL POLLUTANTS OF SEDIMENT OF DIFFERENT GRAIN SIZES

Generally, sediment in natural rivers is non-uniform, and sorption capacities of different grain sizes vary greatly. In order to quantitatively describe sorption of heavy metal pollutant by sediment in natural rivers, the concurrent sorption by sediment of different grain sizes should be studied. By combining systematic laboratory experiments and theoretical analysis the concurrent equilibrium sorption model and the concurrent sorption dynamic model by sediment of different grain sizes have been set up. Both of them indicate that there is no competition or interference among different grain sizes, its sorption content of unit weight of sediment is the sum of the sorption contents of each grain sizes , and the content of each grain size in non-uniform sediment. Furthermore, formulas for determining characteristic parameters ( b and k) in the Langmuir sorption isotherm for non-uniform sediment are deduced as follows: These can be used as a tool for predicting the sorption content of non-uniform sediment     

STUDY ON SORPTION OF HEAVY METAL POLLUTANTS BY SEDIMENT PARTICLES

Sorption of heavy metal on sediment particles is studied theoretically am experimentally. Sorption processes of heavy metal pollutants on sediment particles can b well described by Langmuir model. Parameters in the model b,,k and k1 depend on proper ties of sediment and water, and have nothing to do with sediment concentration. By com bining the sorption dynamic equation and the mass conservation equation, the variation c N(sorption content of heavy metal pollutant by specific weight of sediment) and c (con centration of heavy metal pollutant in water phase) with time can be deduced. Further more, formulas for calculating the equilibrium sorption content N and the equilibriur concentration of heavy metal pollutant in water phase c are established too. Experimenta data well coincide with theoretical formulas. These can be treated as the basis for furthe quantitative study of sediment sorption-desorption characteristics.     

3D model study of coal/coke combustion in a blast furnace effects of coal properties

A three-dimensional mathematical model of the combustion of pulverized coal and coke has been developed.The model is applied to the blowpipe-tuyere-raceway-coke bed region in an ironmaking blast furnace in one computational domain,which includes two parts:pulverized coal combustion model in the blowpipe-tuyere-raceway cavity and the coal/coke combustion model in the surrounding coke bed.The effects of coal properties are examined comprehensively,in terms of coal burnout and gas species distributions.The ...     

分置式膜-生物反应器处理染料废水的试验研究

对分置式膜—生物反应器处理染料废水进行了研究,进水COD为 350～400mg/L,出水为30～70mg/L,COD去除率约85％,膜的截留去除COD约占10％。TOC去除率为85％～90％,色度去除率约为70%,膜生物反应器中的活性污泥的粒径范围为1～100μm,平均粒径40μm,酶的含量为7.95mgTTC/gVSS。     

防空导弹制导控制系统混合计算机实时仿真

本文扼要介绍了导弹制导控制系统在大型现代混合计算机上进行实时系统仿真建模、验模和运行的全过程,说明了建立实时仿真模型的重要性。文章用较大篇幅详细阐述了建立导弹飞行实时混合仿真模型时,分配数字、模拟任务和确定混合仿真帧时的原则;编程控制A/D、D/A通道数据转換,设计气动多变量函数,坐标变换实时仿真模型的方法以及仿真模型校验方法。     

海洋含气土工程特性研究现状

近年来,海洋工程建设过程中出现灾害事故的一个重要原因是海床含气土中天然气水合物受外界扰动而分解,改变了海洋地基土体的工程性质,因此,对于海洋含气土工程特性的研究越来越受到人们的重视.文章总结了海洋含气土工程特性的研究现状,阐述了含气土工程特性室内试验的样本来源,介绍了评价海洋含气土工程特性的几种试验方法:微观结构观测试验、声学特性测试试验和土体力学特性试验,并对含气土工程特性研究中存在的问题和发展趋势进行了讨论.     

基于知识重用的标准件建库方法研究

知识重用是一种在已有的设计知识和经验的基础上,进行新产品设计的过程。通过分析基于知识的标准件模型知识表达、重用、搜索等关键技术,提出了将标准件的尺寸信息、开孔信息、装配信息、配置信息等提取出来,建立基于知识重用的标准件库,从而实现标准件的自适应,提高了产品设计的质量和效率。     

板类零件数控切割的自动编程

利用ＣＡＤ系统与ＮＣ连接自动编程的方法，研究了工业锅炉板类零件数控切割。通过对ＡｕｔｏＣＡＤ状态下的零件图形进行处理，读取图形交换ＤＸＦ文件中的几何信息，可以自动确定切割路线和自动编制数控加工程序。结果表明，该方法可以大大提高编程的可靠性、数控切割效率及自动化水平。