压铸过程工艺参数与压铸机及压铸模具相关的数学模型与分析

压铸过程的合理工艺参数的选择是保证压铸件质量的核心，压铸机及压铸模具正确合理的调节是保证工艺参数的关键。本以压铸过程和物理学原理出发，讨论与压铸机及压铸模具相关的运动过程的数学关系，揭示压铸工艺参数的本质。     

我国台湾电子废物回收利用的法律及实施

一、台湾电子废弃物回收利用的相关法规政策 1997年7月,台湾环保署依据《废弃物清理法》,宣布废弃的电视机、电冰箱、洗衣机及空调为不易清除处理及长期不易腐化的一般废弃物.翌年3月起开始回收处理,废家电专业处理机构2000年1月起陆续建设完成并运营处理.法律规定了废家电的回收处理责任为生产商和进口商,要求责任方全部负担回收处理费用,为此成立了专项基金.     

大型预焙铝电解槽电解质过热度的测定以及炉帮与过热度的关系

铝电解槽炉膛内形的规整与否严重影响着电流效率,而铝电解槽的炉膛内形与电解质的过热度有很大的关系。本文通过现场测试电解温度和炉帮厚度,实验室测定电解质初晶温度的方法,考察了电解质的过热度以及过热度与炉帮厚度之间的关系。通过研究发现,过热度低于12℃时,电解槽可形成良好炉帮。     

全脸式面罩及罩体模具设计

介绍一种新型全脸式防护面具面罩的结构特点及其罩体、阻水罩模具的设计。罩体和阻水罩采用橡胶压制成型 ,根据罩体和阻水罩的特点 ,详细介绍了模具整体结构设计、分型面的选择、定位方式的确定及活块、镶块的设计     

电机端盖成形工艺及模具设计

介绍了电机端盖冲压成形工艺及其模具设计 ,对中心带局部变形结构的拉伸件提供了工艺分析与模具设计的范例     

胺法冷芯盒制芯工艺中的影响因素

简要介绍了三乙胺法冷芯盒制芯工艺的特点及原理，分析了影响三乙胺冷芯盒制芯工艺的因素及在生产中如何进行有效的控制。     

Numerical simulation of the stress-strain curve and the stress and strain distributions of the titanium-duplex alloy

The stress-strain curve of an a-β Ti-8Mn alloy was measured and then it was calculated with finite element method (FEM) based on the stress-strain curves of the single α and β phase alloys.By comparing the calculated stress-strain curve with the measured one,it can be seen that they fit each other very well.Thus,the FE model built in this work is effective.According to the above mentioned model,the distributions of stress and strain in the α and β phases were simulated.The results show that the stress gradients exist in both α and β phases,and the distributions of stress are inhomogeneons.The stress inside the phase is generally higher than that near the interface.Meanwhile,the stress in the α phase is lower than that in the β phase,whereas the strain in the a phase is higher than that in the β phase.     

空压机试验台测控系统研究与应用

介绍了空压机总成性能试验台测控系统的总体结构,该系统采用了"软化"的设计思想,并应用模糊控制(FUZZY)算法实现了系统的智能控制。实际应用结果表明,该控制系统调节参数速度快、测量准确、测试范围宽、自动化水平高,各技术指标均符合试验要求。     

弧齿锥齿轮和准双曲面齿轮模型设计的方法及展望

Accurate modeling of spiral bevel and hypoid gear is the foundation of the tooth contact analysis(TCA) technology and error correction technology of the tooth surface,which is the key technology in digitized manufacturing. This paper summarized the related achievements and divided the methods of modeling spiral bevel and hypoid gear into three categories,including modeling by discrete points on the tooth surface,curve fitting,and simulation machining,and generalized the main steps and the key ideas of each method. At the same time,this paper analyzed the problems and inadequacies existing in the process of model design. Three directions were proposed for modeling of spiral bevel and hypoid gear in the future,that are more accuracy,more efficiency and more flexibility. The paper provides some methods that make the design and machining of spiral bevel and hypoid gear faster and more accurately.在弧齿锥齿轮和准双曲面齿轮的数字化制造中,精确模型是其关键技术—齿面接触分析技术(TCA)和齿面误差修正技术的基础。总结和归纳了近些年来国内外相关研究成果,将弧齿锥齿轮和准双曲面齿轮的模型设计方法分成离散点、曲线拟合、仿真加工模型设计3种类型,并概括了其关键思想与步骤。同时,分析了模型设计过程中存在的一些问题与不足,整合先进方法和思想,对未来弧齿锥齿轮和准双曲面齿轮模型设计研究提出了高精度、高效率、高柔性3个发展方向,为弧齿锥齿轮和准双曲面齿轮更加快捷精确地设计和加工提供了参考。     

花岗石显微硬度与磨加工效率相关性的试验研究

本文对10种花岗石分别进行钻进、磨削和锯切3种磨加工试验,分析了花岗石加权显微硬度和硬度的离散值与磨加工效率的相关性,提出了相应的复回归方程式,以此为基础结合实际生产,将花岗石可加工性分成三大类别。     

电渣熔铸模具钢/低合金钢双金属平板件组织与性能的研究

采用电渣熔铸方法制备Cr12MoV模具钢/40Cr结构钢双金属复合材料,研究了热处理工艺参数对双金属组织和性能的影响.结果表明:采用适当的熔铸工艺可获得界面结合牢固、均匀平整且过渡层适当的双金属平板件.双金属Cr12MoV钢一侧的淬火和回火组织为回火马氏体 网状共晶碳化物 细小粒状二次碳化物 少量残余奥氏体.双金属的最佳热处理工艺为980 ℃淬火 230 ℃回火,其冲击韧度αk值可达25 J/cm2以上,工作层硬度HRC≥62.     

细丝小马鞍型埋弧焊试验及其在汽包管座角焊缝上的应用

为了实现锅炉汽包骑坐式管座角焊缝的机械化、自动化,达到高效、高质量焊接的目的,从设备选型、焊材匹配试验、接头性能试验、工艺参数的确定等方面进行了系统的工艺试验工作。试样结果表明:选用合理的工艺参数,采用细丝马鞍形埋弧焊工艺方法焊接汽包骑座式管座角焊缝,与焊条电弧焊对比,可以较大幅度提高焊接效率,同时更利于保证焊接质量。     

面包箱左右侧板成形工艺及模具设计

通过对圆筒形和矩形组合拉伸件的工艺计算和分析 ,确定了合理的工艺方案 ,同时介绍了模具的结构特点及工作过程 ,并充分利用工件相互对称的特点 ,减少了模具的数量     

Crystallography of the past and in the future

ABSTRACT

This paper is partly a summary of the book ‘From a grain of salt to the ribosome’ [1 OlovssonI, LiljasA, LidinS. From a grain of salt to the ribosome. Singapore: World Scientific; 2014; ISBN 978-9814623117.[Crossref] , [Google Scholar]], with extension on some points. Sometimes the developments in science may be very rapid and not fully appreciated at all corners of the scientific society. Harry Clary Jones was a well-known chemist at Johns Hopkins University at the turn of the previous century. He had, in his earlier days, spent time in the laboratories of Wilhelm Ostwald in Leipzig, Svante Arrhenius in Stockholm and Jacobus van’t Hoff in Amsterdam. He wrote many papers and twelve books. In 1913 he claimed in a book [2 JonesHC. A new era in chemistry – some of the more important developments in chemistry during the last quarter of a century. New York : D van Nostrand; 1913. [Google Scholar]]:

We do not know the formula of rock salt, or of ice; and we have no reliable means of finding out these simplest matters about solids. Our ignorance of solids is very nearly complete.

It is evident that he was unaware of the very recent developments and the revolution in chemistry that had just taken place with the birth of X-ray crystallography.     

Corinthian bronze and the gold of the alchemists

Alloys that went under the name of Corinthian Bronze were highly prized in the Roman Empire at the beginning of the Christian era, when Corinthian Bronze was used to embellish the great gate of Herod’s Temple in Jerusalem. From the ancient texts it emerges that Corinthian Bronze was the name given to a family of copper alloys with gold and silver which were depletion gilded to give them a golden or silver lustre. An important centre of production appears to have been Egypt where, by tradition, alchemy had its origins. From an analysis of the earliest alchemical texts, it is suggested that the concept of transmutation of base metals into gold arose from the depletion gilding process.     

电机定子冲片内外圆同轴超差原因分析及解决方案

对电机定子冲片内外圆同轴度超差原因进行分析,通过对模具定位轴结构的改进,避免了模具刃磨时对定位轴反复拆装造成的定位轴位置度的改变,解决了因定位轴原因造成的定子冲片同轴度超差。     

叉车桥壳的拉伸缺陷分析及解决措施

从板料拉伸变形可能产生的缺陷入手 ,将传统的用2副模具拉伸的工件用1副模具成形 ,在模具结构上进行了改进 ,以保证设计目标的实现。在试模中准确地分析产生缺陷的原因 ,并予以消除