用含Pb、As、Sn地方生铁砂型铸造生产D型石墨铸铁的研究

基于Ph、As、Sn等元素有增大铁液过冷倾向的作用，利用含Ph、As、Sn的地方生铁，采用合金化和砂型铸造可以获得D型石墨铸铁，对其工艺方案进行了研究。用正交试验法设计试验方案，得到最佳工艺方案为：在亚共晶成分（WB％：3．2C，2．1si）的铁液中加入适量的铝（0．6％）和钛（0．8％），可以得到含有100％D型石墨的铸铁，其抗拉强度最高可达276MPa。     

Cu-Zn-Al形状记忆合金直接淬火和分级淬火后马氏体稳定性的研究SCIEI

用透射电镜,X射线衍射仪和电阻法研究了Cu-14.84wt-％Zn-7.75wt-％Al形状记忆合金在直接淬火和分级淬火后马氏体的稳定性。试验结果表明,直接淬火和分级淬火(150℃,2min)后于室温时效约3h的马氏体均为M18R结构,但刚直接淬火后马氏体并不稳定,其某些衍射峰位置和电阻率均随室温时效而变化;而分级淬火(150℃,2min)后马氏体是稳定的,其所有衍射峰位置和电阻率几乎不随室温时效而变化。上述结果可用“马氏体再有序化机制”解释。     

液力偶合器用铝合金材料的超声波检测

铝硅合金ZAlSi9Mg(代号ZL104)具有优良的力学性能,在大气和淡水中不宜腐蚀、耐磨耐热、塑性成形能力强、铸造性能和切削加工性能好、不易产生“咬死”现象,是一种优良的绿色环保材料[1],被笔者公司广泛用于液力机械产品中的涡轮、泵轮、离合器等高速运转部件,降低了经济成本,也     

射线检测中运动模糊图像的恢复

X射线实时成像检测中,若曝光时间内工件和X射线图像采集设备有相对线性运动,会造成图像运动模糊降质。提出利用运动模糊点扩展函数的频域特征和Hough变换得到模糊图像的运动方向,并将之旋转到水平轴方向,利用差分法求解运动模糊点扩展函数的长度。并用Wiener滤波的方法,恢复降质的图像,取得了较好的效果。     

联合法提镓工艺研究

针对联合法氧化铝厂循环母液含镓的特点 ,提出采用化学法和树脂吸附法相结合的方式从烧结法拜耳法循环母液回收镓的新工艺 ,并通过小试和扩大试结果分析 ,从技术和经济诸方面阐述了该工艺的可行性     

Influence of electroplating conditions on magnetic properties of Fe-36wt.% Ni alloy film

A Fe-Ni soft magnetic film was prepared in sulphate solution by electroplating. The influences of the molar ratio of n [Fe2+ ]/ n [Ni2+ ], current density, bath temperature, pH and L-ascorbic acid concentration on magnetic properties of Fe-Ni alloy film were investigated. The results show that the saturated flux density(BS) of the film increases initially and decreases after it reaches the specific value with the increase of n [Fe2+ ]/ n [Ni2+ ] molar ratio, current density, bath temperature and pH. However, the relationship between L-ascorbic acid concentration and B S keeps linear. It is observed that the coercive force( Hc) is enhanced with the increase of n [Fe2+ ]/ n [Ni2+ ] molar ratio, current density and pH. By comparison, when the bath temperature increases, Hc always decreases. With the increase of L-ascorbic acid concentration, the coercive force increases initially and then decreases.     

INVESTIGATION ON CRYSTALLIZATION KINETICS OF Pd-Cu-Si GLASS

The crystallization kinetics of Pd-Cu-Si glass was studied by means of diferential scanningcalorimetry-Ⅱ.According to Kissinger peak shift meth(?)d and Arrhenius equation,theapparent activation energy was calculated.The crystallization kinetics follows Johnson-Mehl-Avrami equation with n=3.0 within 0.15相似文献   

板料弯曲回弹的有限元模拟影响因素研究

阐述了板料成形数值模拟中回弹问题的研究历史和发展现状,分析了塑性弯曲加工中工件发生弯曲回弹的原因、特点及有限元模拟过程的影响因素,总结了回弹模拟的算法,从成形过程模拟和回弹计算两方面系统分析了影响回弹模拟准确性和收敛性的主要因素及改进方向,讨论了模具设计中回弹的补偿算法 ,并提出了当前控制回弹的基本方法     

Phase transformation behavior in Al-Zn-Cu alloys by hammering

The 5Cu40Zn55Al and 15Cu20Zn65Al alloys were prepared in the AI-Zn-Cu system, There exist the metastable phases ε and θ in the two alloys after homogenization treatment and furnace cooling, respectively. It is shown that the particles are refined from 3 mm to less than 10 μm after hammering the two alloys but there are still metastable phases. This means that the phase constituents of the two alloys have no changes by the deformation, which is different from that by balling. The phase constituents are not changed at room temperature by hammering, which is dependent on the deformation mechanism of hammering.     

军队医院网络信息系统的安全分析

随着网络技术在医院的应用,其安全性日益受到重视。首先结合军队医院信息系统网络应用的特点,从硬件系统、软件系统、环境因素、人为因素等方面分析该网络系统的安全性;最后研究该网络系统安全可能造成的威胁,并提出安全应对措施。