Stage-efficiency of centrifugal extractor used in nuclear industry

1　INTRODUCTIONComparedwithamixer settlerorpulsedcolumnusedinthenuclearfuelreprocessingextraction pro cesses,ashort residence timecentrifugalextractorcatchesresearcher seyesbecauseofthe goodphaseseparationandasmallhold upvolume .Itshowsthefollowingadvantagesinthenuclearindustry[1] :1)Reducingsolventdegradationduetoradiation ;2 )Reducinginventoryofaqueousandorganicphases ,whichgivesrapidstart upandshut down ;3)Com pactdesignthatcontributestothereductionofplantcost .Manydifferenttypesofcen…     

齿轮精锻的数值模拟与实验研究

本文对空心直齿圆柱齿轮的精锻成形过程进行三维刚塑性有限元模拟和实验研究。通过有限元数值模拟和实验研究 ,得出了直齿圆柱齿轮精锻过程的金属流动规律和变形力学特征 ,揭示了直齿圆柱齿轮精锻过程的变形机理 ,数值模拟结果与实验结果吻合较好     

金属注射成形技术进展

分析了影响金属注射成形（ＭＩＭ）产业化进程的两个主要技术因素，即适合ＭＩＭ要求的原料粉末的生产方法和ＭＩＭ生产工艺，并概述了目前ＭＩＭ技术的发展状况。     

钴纳米颗粒的制备及其表征

采用简单的溶液还原方法，以聚乙烯吡咯烷酮（PVP，MW=58，000）作为高分子表面修饰剂，用水合肼（50％）作为还原剂，经回流处理，成功地制备出了分散性较好的钻纳米颗粒。利用XRD、TEM、SQUID等实验方法对产物的形貌、物相及磁性进行了表征。结果表明，产物为六方结构。其饱和磁化强度为153emu／g-1．62μB／Co，是体相材料的饱和磁矩的95％，其矫顽力为5174A·m^-1。此方法的优点在于反应条件温和、成本较低，重复性强、产率高且宜于控制。     

金属塑性成形过程的微观组织模拟与优化技术研究现状

介绍了金属塑性成形过程中微观组织演变的数学模型和常用的微观组织优化目标函数 ,给出了金属塑性成形微观组织模拟和优化的主要方法———微观遗传算法和灵敏度分析方法的基本原理 ,叙述了近年来国内外金属塑性成形微观组织模拟与优化研究概况。     

稀盐酸中锰结核还原浸出溶液净化除铁

针对酸性氯化物中黄铁矿还原浸出锰结核的溶液成分特点，选择黄钠铁矾法进行了沉淀分离铁的研究。结果表明温度和晶种以及溶液ｐＨ值是影响铁矾沉淀的重要因素。在ｐＨ２．０左右，溶液温度高于９０℃，足量晶种加入的情形下，１５０ｍｉｎ后可将溶液中的铁含量降至０．１ｇ／Ｌ。沉矾过程的表观活化能为９４．６６ｋＪ／ｍｏｌ。黄铁矿氧化生成的硫酸根随铁一同沉淀，从而消除了ＳＯ２－４在氯化物体系中的积累。     

A backward extrusion analysis by the rigid–plastic integralless–meshless method

The rigid–plastic integralless–meshless method is applied to the analysis of plane strain backward extrusion. The rigid–plastic integralless–meshless method, based on the moving least squares approximation and the partial differential equations of mechanical equilibrium, is a truly meshless method. In addition, since there is no any integration in the formulation of the rigid–plastic integralless–meshless method, this method is also an integralless method. Compared with the conventional rigid–plastic FEMs, the rigid–plastic integralless–meshless method has some advantages that are briefly no mesh generation, no remeshing and no integration. Compared with BEMs and FBEMs, the rigid–plastic integralless–meshless method is found to have some merits such as sparse matrix, no singularity, no integration and no fundamental solution. Contours of the equivalent strain rate, the equivalent strain, the equivalent stress and the shear stress, etc. of the backward extrusion analysis using the rigid–plastic integralless–meshless method are obtained successfully.     

流变成形浆料制备技术发展动向及其对策

提出了流变成形对半固态浆料的质量要求，归纳了与流变成形相应的半固态浆料制备新工艺。指出半固态金属流变成形的关键技术为如何快速获得理想的等轴非枝晶半固态组织，固相率、晶粒形状、晶粒尺寸和粘合度是表征半固态浆料的主要指标。介绍了低转速输送管控制浇注制备半固态浆料的新工艺，半固态组织的主要指标可达到：①形状因子1．08～1．36；②固相率20％～60％；③晶粒平均直径40～100／μm；④固相体积粘合度小于0．22。介绍了等轴非枝晶形成机理的研究现状，指出微观组织数值模拟技术是研究等轴非枝晶形成机理的新趋势、新思路，采用元胞自动机模拟技术对其进行了初步研究。     

模糊控制在半固态浆料制备装置中的应用

介绍了低转速输送管半固态浆料制备装置的原理和组成，采用模糊控制技术改进了该装置的温度控制系统，并详细介绍了该控制系统的总体设计及软硬件方案。试验证明，模糊控制技术的应用提高了该装置的温度控制效果，实现了良好稳定的铝金属半固态浆料微观组织控制作用。     

Effects of CeF3 on properties of self-shielded flux cored wire

0 IntroductionSelf-shielded flux cored wire is a newly developedwelding material used without gas protection. Use of suchcored wires has grown rapidly in developed countriesbecause of the following advantages: simple use, goodwind resistance ability, lower cost resulted from highproductivity and strong desulfurization ability[1]. Self-shielded flux cored wires are preferred for on-site weldingsuch as ship and barge building, storage tank, bridge,offshore oil platform buildings and so on[2 -3].…