The influence of solid-phase concentration on the performance of electrorheological fluids in dynamic squeeze flow

The yield stress of electrorheological (ER) fluids increases by orders of magnitude when electric field is applied across them. In the absence of the field, ER fluids behave as Newtonian fluids. This paper is concerned with an experimental investigation to determine the rheological performance of ER fluids, consisting of a dielectric liquid carrier with a range of solid-phase concentration. The ER fluid was contained in a squeeze cell, which during motion subjects the fluid to both compressive and tensile loading. The results were analysed in terms of the capacity for the transmission of imposed forces across the fluid and showed a great dependence on the applied D.C voltage and the weight fraction of the dispersed solid-phase. In addition, the implications of the results to vibration control, where the ER fluid is employed in an engine mount, are discussed.     

汽车拨叉热处理工艺研究

采用正交试验法,确定的汽车拨叉零件热处理工艺参数组合,满足使用要求;分析了该工艺形成的拨叉表层碳浓度情况和碳浓度梯度分布,获得浅层碳氮共渗碳浓度梯度分布对性能的影响,采用在升温阶段手动通入适量氨气的工艺调整方法,可以缩短均温时间,保证表面硬度达到技术要求,探索了合适氨气流量确保表层不出现过量残余奥氏体和黑色组织的机理,选用MT25656分级淬火油,可以满足零件变形要求。     

叉车门架断裂原因分析

采用化学成分分析、力学性能测试、金相检验以及断口分析等方法对某叉车门架断裂的原因进行了分析。结果表明:由于在门架焊缝收弧部位存在凹坑缺陷和裂纹,形成缺口效应,产生缺口应力集中,加之门架的不对称工作应力的作用,最终造成门架发生了疲劳断裂失效。     

Plasma induced luminescence (PIL)

Laser-induced breakdown spectroscopy (LIBS) is well known tool for elemental analysis of solid, liquid and gaseous materials. The species emission life times in typical plasma are in 10–50 μs range. It is recognized that after this time following plasma formation any useful information does not exist. It is not the case when matrix subjected for plasma excitation is capable to luminescence. In such case UV, visible photons and possibly X-rays created by plasma excite the matrix luminescence, which may be detected after the corresponding delay when plasma emission becomes comparable by its intensity with luminescence. It may be supposed that plasma created by other means, for example, by spark, will also generate luminescence. Evidently it is new luminescence excitation mechanism and correspondingly new luminescence type, plasma induced luminescence (PIL).     

Linear eigenvalue code for edge plasma in full tokamak X-point geometry

A new code is presented for solving linear eigenvalue problems from fluid models of the edge plasma of tokamaks. The 2DX code solves linearized fluid equations in a 2D cross-section of the plasma, with toroidal mode number resolving the third dimension. Geometry capabilities include both closed and open field lines, allowing solution of X-point problems as well as a variety of other toroidal and cylindrical systems. The code generates a pair of sparse matrices forming a generalized eigenvalue problem which is then solved using a standard sparse eigensolver package. Use of a specialized equation parser permits a high degree of flexibility in both equations and coordinate systems. Both analytic and full geometry benchmark cases are presented.     

A Study on the Electrochemical Deoxidation Using ZrO2 Based Solid Electrolyte and a Periodic DC Voltage

An electrochemical deoxidation using a ZrO₂ based solid electrolyte was investigated to control the interfacial oxygen concentration between the molten steel and ZrO₂. The electrochemical deoxidation cell consisted of an MgO stabilized ZrO₂ and an external power supply. In a previous study with constant external DC voltage, the oxygen concentration at the interface between the solid electrolyte and the molten steel was decreased to 2.2 ppm, which was the limit caused by the cathodic over‐potential when a constant external DC voltage was applied. In the present study, a novel process of using a periodic or cyclic voltage for the electrochemical deoxidation cell was developed, to surpass this limitation caused by the over‐optential of the electrochemical cell and thus decreasing the oxygen concentration to sub‐ppm levels at the interface between the molten Fe and the solid electrolyte.     

铜冶炼渣尾矿综合利用现状及研究

铜冶炼炉渣含有大量的有价金属元素,经过选矿工艺处理后,大部分铜被回收,选出的渣精矿返回熔炼炉,渣尾矿外售至水泥厂,尾矿中有价金属仍存在较大利用价值,在现有工艺流程后增加磁选工艺,磁选后的铁精粉用作炼钢配料,尾矿外售。主要介绍了熔炼渣及尾矿成分,现有工艺尾矿处理方式,新工艺的应用及实践。     

红外低硫传感器信噪比改善方法研究

低硫的红外探测是一个非常重要的研究领域,但由于红外硫的吸收峰在一个特殊的波段,与人体红外波段重合,所以国外的先进技术大都对中国封锁,而国内的低硫传感器存在交叉吸收误差,检出限不够、检测精度低等缺陷;文章以煤中硫元素的测试为基础,研究采用了电调制热释电红外传感器在测量硫元素过程中存在的以上问题,主要开展了探测器稳定性、恒温测试、气室噪声、滤波等改善传感器信噪比的相关改进设计和实验,并提出了优化的方案,优化后经过实验测试,整个测试系统的信噪比提升近50%,检出限从原来的100 ppm提升到近10 ppm;低硫测量平均值为0.382%,SD为0.006%,RSD为1.2%,瓶内RSD为0.9%;达到了低硫的高精密测试。     

炉水中氯离子浓度高的原因分析与预防措施

氯离子对亚临界机组的腐蚀危害极大,其腐蚀表现形式主要是破坏水冷壁管金属表面的钝化膜,进而向金属晶格里面渗透,引起金属表面性质的变化。分析炉水系统中氯离子对金属腐蚀的现象,并针对炉水系统内部氯离子的来源,提出了相应的解决措施。     

基于有限元法的汽轮机轴系磨损故障处理

汽轮机轴系磨损部位的合理处理关系到机组的运行安全,为了使处理方案更加科学合理,采用有限元软件ANSYS建立轴系磨损部位的局部有限元模型;通过合理设置边界条件,求出了不同处理方案下磨损部位的应力集中系数,为方案的优化选择提供依据。以某电厂磨损故障为例,采用该方法对处理方案进行优化,计算结果表明,优化后的方案较大幅度地降低了磨损部位的应力集中系数,为机组的安全运行提供了可靠的保障,说明该方法是有效可行的。本文提出的方法适用于类似故障的处理。