金企沪金套利大获全胜——沪金期现套利分析

自沪金期货上市以来,一直与黄金现货保持同步走势,主力合约维持与上海黄金交易所现货95金1-2元的升水状态。但最近一周这种平衡状态被打破,上周五收盘时,沪金0812合约收盘价与金交所T＋D合约收盘价相差8．85元／克!     

动圈式交流弧焊机设计中铜铁比值的探讨

由于交流弧焊机用的是工频交流电源,每秒一百次过零点,因而对电弧的稳定燃烧,就成为众所关心的问题。在设计中,考虑焊接性能就涉及产品的铜铁比值。在符合     

铜-锡配比对Cu基耐磨合金耐磨性的影响

采用粉末冶金工艺制备了w(Sn)/w(Cu+Sn)比值分别为0、6%、9%和12%的Cu基耐磨材料,对其组织结构、显微硬度变化幅度和不同载荷下的摩擦磨损性能进行分析。结果表明,Cu基耐磨材料中加入Sn可明显提高其显微硬度和耐磨性;w(Sn)/w(Cu+Sn)为9%时,主要磨损机制为磨粒磨损,并且在高载荷下呈现出了较好的耐磨性。     

永磁无刷直流电机性能的影响因素的数学推导与仿真分析

在理论上推导出电机性能的影响因素是科学设计电机的前提。为了在理论上推导出影响永磁无刷直流电机的电磁转矩和电磁效率的影响因素,并用虚拟仿真加以验证,按照电机学的粘性阻尼理论,结合电磁学基本原理推导了电磁转矩和电磁效率关于各设计变量的公式。通过公式可以发现,此类电机的电磁转矩和电磁效率可用多元函数来表达,两者的决定性因素是额定电压、平均半匝长系数、永磁体厚度、极数和气隙等设计参数,并且经过数学分析可以得到电磁转矩和效率关于各设计变量的变化趋势。为了进一步证实理论推导的正确性,ANSYS Electronics Desktop软件的RMxprt模块进行了此类电机性能影响因素的仿真分析,分析结果与理论研究基本一致。这些趋势可以为永磁无刷直流电机研发人员选取优化设计变量和调整变量的数值提供方向。     

心血管的卫士——铜

<正>专家指出:铜作为动物和人类的必需微量元素, 具有重要的生理生化功能。微量元素与心血管病关系的研究报告很多。     

注重学术服务民族——论罗家伦的大学理念

在民国教育史上,作为国立清华大学和中央大学的校长,罗家伦始终以发展学术为办理大学的中心任务,其大学理念体现为:大学应以文、理学院为中心,兼顾应用科学的发展;大学应以学术为标准,选聘优良师资;大学应以学术研究为灵魂,为人类增加知识总量;大学要把握时代的精神和需要,为民族的生存和发展做贡献.在近代中国复杂多变的历史条件下,罗家伦坚持学术救国的信念,执着地以大学作为振兴民族文化的基地,他对清华大学和中央大学的办理功不可没,其大学理念与办学实践有值得称道之处.     

铝——铜的浸焊

我省各电机、变压器制造厂均有试制及生产铝线电机、铝线变压器的任务,而铝—铜、铝—铝的焊接工艺是个关键性的问题。目前我省大都采用气焊工艺,效率低,质量不可靠,不能适应大批生产的需要。这次我们应用优选法,在学习兄弟单位先进经验的基础上,在各级领导的重视和支持下,试验成功了铝—铜、铝—铝直接浸焊工艺。经大电流冲击,抗拉试验,证明此种焊接符合要求。     

铜——人类亲密的朋友

<正> 岁月的风尘往往会抹去人类的种种努力,但当人们在埃及金字塔内看到一段铜水管道虽经历了五千年的时光流转,仍能淌出潺潺清流,不禁会暗暗欣慰,大自然给人类留下了历经久远的物质——铜。 铜是一种质地坚硬的金属,耐腐蚀,能在各种不同环境中不受损坏。铜在化学活性排序的序位很低,仅高于银、铂、金,因而性能极稳定。铜在大气中还会生成氧化铜膜,防止铜进一步氧化腐蚀。所以当许多同时期的     

铜——不锈钢翅片管的氩弧焊

热沉中采用了大量由Ｔ２（厚度２ｍｍ）翅片与１Ｃｒ１８Ｎｉ９Ｔｉ（３２×２．５ｍｍ）管焊接的翅片管。由于两母材的物理性能相差较大,存在着热裂纹和渗透裂纹的倾向,不锈钢的渗透裂纹更具危害性,因而焊接难度较大。为此选择多种填充金属进行了可焊性试验。镍基焊丝ＥＲＮｉＣｒ－３的Ｍｎ等还原性元素能有效地改善熔敷金属的流动性并抑制热裂纹的产生,因此确定该焊丝为填充金属。通过试验确定了最佳的焊接参数匹配,并设计了焊接专用工装。结果证明,采用该工艺焊接的接头具有良好的综合性能,确保了铜—不锈钢翅片管承受液氮（－１９６℃）与高温蒸汽（２００℃）的交替冲击。     

铜的回收与再生利用——废杂铜利用的途径

有色金属的再生利用是一个发展较快同时又是一个工艺技术发展比较固定的领域。即使是在信息化高度发达的今天，人们也依然遵循过去在实践中总结出来的一些经验和典型的工艺过程，这些工艺过程针对的物料相对固定，工艺路线也相对固定；产品的用途也相对固定。不少读者通过多种途径表达了一些共同的意愿，那就是希望我们能够介绍一些再生金属方面的实用技术，为此，我们从一些专家过去撰写的论文中选编了一些文章，这些文章中所提出的工艺路线虽然已经用了多年，但是今天看起来仍然有着不少的指导意义。特别是对于刚刚起步的下行再生利用企业还是有一定的借鉴作用的。这篇废杂铜的直接利用途径的介绍选自国内贸易部物资再生利用研究所高级工程师张邦安先生曾经发表过的文章。     

结晶器铜管的失效分析

针对结晶器铜管在生产中出现的硬度不均、表面＂桔子皮＂、脱方现象,秦皇岛首钢长白结晶器有限责任公司采用调整加热温度和保温时间的方法,保证硬度符合标准,并解决了铜管裂纹和难以加工问题;控制铜管的变形量〉15%,消除了铜管的＂桔子皮＂现象;采取时效处理使铜管不在出现脱方现象。     

砷酸铜制备工艺过程热力学分析

绘制了Cu-As-H2O系电位－pH图、不同As浓度下lg[Cu]T[As]T)-pH图以及Fe-As(V)-H2O系lg[Fe]T-pH图等,分析了由墨铜渣制备胂酸铜过程的热力学。酸性氧化浸出可同时浸出Cu和As,pH＝2左右脱脱铁率可达99％以上。铜砷比和pH值的不同,可以得到不同形式的砷酸铜;CuHAsO4,Cu2AsO4OH,Cu5H2(AsO4)。在胂酸铜制备工艺条件下,所得砷酸铜分子式为Cu5H2(AsO4)4。热力学分析结果与XRD相一致。     

Pore structure analysis of directionally solidified porous copper

Directionally solidified porous copper is considered as a potential candidate in the field of microchannel heat sinks.By the Bridgman-type directional solidification method,a porous copper ingot was fabricated.Evolution of the porosity,pore number density,average pore diameter and average interpore spacing at different ingot heights was investigated.The results show that with the increase of ingot height,the porosity firstly increases and then basically remains unchanged from the ignot height of 65 mm;the pore number density rapidly decreases at first,and the decreasing speed becomes slower when the ignot height higher than 85 mm;the average pore diameter increases and then remains unchanged from the ingot height of 85 mm;the average interpore spacing increases,and the increasing speed of average interpore spacing becomes slower with the increase of height to higher than 85 mm.In order to study the evolution of diameter and spatial distribution of pores,the distribution ranges of pore diameter,nearest-neighbor distance and radial cumulative pore number were analyzed.As the ingot height increases,the distribution ranges of pore diameter and nearest-neighbor distance firstly increase and then tend to be stable.There are no pore clusters and for long distance,the spatial distribution of pores is uniform at different ingot heights.Pore structure and 3D pore morphology of porous copper were observed with the help of light illumination and X-ray tomography.Pore nucleation,pore interruption,pore coalescence,diameter change of pores and lateral displacement of pores were found to exist in the pore structure.     

电力行业铜抱杆线夹失效分析

针对安徽电网近期发生的几起典型铜抱杆线夹失效案例,并结合线夹的类型分析失效原因,提出今后金属监督的重点。结果表明,铜抱杆线夹频繁开裂主要与其合金成分和成型工艺有关。对于黄铜线夹,主要加强合金成分的检测,可辅以现场电导率检测或硬度检测;对于紫铜线夹,主要加强对强度的校核以及对成型质量的外观检测。同时,注重安装阶段紧固力矩的复核。     

Numerical simulation analysis of Guixi copper flash smelting furnace

A numerical simulation analysis for reactions of chalcopyrite and pyrite particles coupled with momentum,heat and mass transfer between the particle and gas in a flash smelting furnace is presented.In the simulation.the equations governing the gas flow are solved numerically by Eular method.The particle phase is introduced into the gas flow by the particle-source-in-cell technique(PSIC),Predictions including the fluid flow field,temperature field,concentration field of gas phase and the tracks of particles have been obtained by the numerical simulation.The visualized results show that the reaction of sulfide particles is almost completed in the upper zone of the shaft within 1.5m far from the central jet distributor (CJD)type concentrate burner,The simulation results are in good agreement with data obtained from a series of experiments and tests in the plant and the error is less than 2%.     

Corrosion domain analysis of copper corrosion in aqueous media

Abstract

The technology that is being developed in Sweden for the disposal of high level nuclear waste calls for storage of the waste in copper canisters, which are encapsulated in a bentonite buffer contained in drill holes in the floors of drifts (tunnels) in a granitic rock repository. A controversial issue has arisen during the development of this technology: that copper, when in contact with pure water under anoxic conditions corrodes and hence is not immune as previously believed. This issue is resolved in the present paper by deriving corrosion domain diagrams as a means of presenting the thermodynamics of the system in the clearest form possible, when assessing the immunity and activation of copper.     

Chromatographic analysis of copper patinas formed in the atmosphere

Gas chromatography/mass spectrometry and ion chromatography have been used to characterize the water and acetone soluble components of copper patina formed in the atmosphere. The patina samples examined were from the Statue of Liberty in New York Harbor and from the copper roof at AT&T Bell Laboratories in Murray Hill, New Jersey. Sulfate, nitrate, chloride, acetate, formate, and oxalate were detected in the water extract of the patina. Analysis of the acetone extract revealed the presence of organic compounds commonly detected in precipitation and associated with airborne particulates. These compounds include several monocarboxylic acids, alkanes, and polynuclear aromatic compounds. The results of the analyses described here provide further evidence for the participation of an organic binder in the formation, growth, and durability of copper patina.     

结晶器铜管在使用中存在的问题及分析

对结晶器铜管在使用中的一些问题进行论述,分析了结晶器铜管的正常使用与工艺、设备的关系.