Growth and Application of Chalcogenides of Lead and Related Compounds

Large grain, low-dislocation, high-quality single crystals of various Pb-salt compounds have been grownreproducibly by the Horizontal Unseeded Vapor Growth (HUVG) technique. The Tunable Diode Lasers withbetter performance have been made with such crystals. The annealing feature, dislocations and diffusion in thecrystals have also been investigated.     

Intensifying digestion of diaspore and separation of alumina and silica

1　INTRODUCTIONDespitetheabundantdepositofbauxitesinChi na ,ofthosepredominantisthediasporictypewithhighalumina ,highsilicaandlowferricoxides .Thebauxitedeposit,withthemassratioofaluminatosil ica(A/S)between 4and 8,accountsfor 80 %ofallthebauxitedeposit.Thenatureofhighsilicacontentdeterminesthatthemainlyadoptedtechniquetopro ducealuminainChinashouldbeBayer sinteringcom binationprocessorevenpuresinteringprocess .Althoughadramaticadvancementinaluminaproductionhasbeenachievedandthetechnolo…     

Synthesis and purification of trialkyl compounds of gallium and indium

The research progress in trialkyl compounds of gallium and indium was discussed from two aspects, one was the chemical synthesis of the compounds and the other was the purification of them. There are three synthesis routes being reported in the first aspect, i.e. the route staring from pure metal, the route starting from the pure metal trihalides, and the electrochemical route. In the second aspect, the purifying methods of decomposition-distillation and zone refining were reviewed.     

Effect of Y on structure and properties of copper and its alloy

The possibility of substituting 72.5Cu-22.7Zn-3.4Al brass for phosphorus bronze in some case that is now extensively used for elastic component, and purifying the scrap copper for recycling metal was investigated. By adding a little amount of rare earth Y into scrap copper and 72.5Cu-22.7Zn-3.4Al brass to research their structure and characteristics, especially the electric conductivity for scrap copper and HV for the brass were researched. The results show that the tensile strength, elongation and electric conductivity （IACS） of 0.38 mm strip of scrap copper with 0.04% Y, are 213.8 MPa, 23% and 98.5% that suit for the elastic components. The tensile strength, elongation and HV of 0.25mm strip of the brass with 0.03% Y are 665.1MPa, 2.86% and 226 that satisfy the usage requirement for the elastic components. Meanwhile, the cost is cheaper than phosphorous bronze because of implying 22.7% zinc in the brass, which has the actual application value.     

Microstructure and properties of composite of stainless steel and partially stabilized zirconia

1　ＩＮＴＲＯＤＵＣＴＩＯＮＯｗｉｎｇｔｏｔｈｅｒｅｑｕｉｒｅｍｅｎｔｓｏｆｒｅｐｅａｔｅｄｓｅｒｖｉｃｅａｎｄｌｏｎｇｗｏｒｋｉｎｇｔｉｍｅｏｆｈｉｇｈｔｅｍｐｅｒａｔｕｒｅｂｕｒｎｅｒｓ ,ｓｕｃｈａｓｓｐａｃｅｃｒａｆｔｅｎｇｉｎｅ ,ｔｈｅｍａｔｅｒｉａｌｏｆｔｈｅｂｕｒｎｅｒｓｓｈｏｕｌｄｈａｖｅｇｏｏｄｓｔｒｕｃｔｕｒｅｐｒｏｃｅｓｓａｂｉｌｉｔｙ ,ａｓｗｅｌｌａｓｈｉｇｈｔｅｍｐｅｒａｔｕｒｅｒｅｓｉｓｔａｎｃｅ ,ｔｈｅｒｍａｌｓｈｏｃｋｒｅｓｉｓｔａｎｃｅａｎｄｔｈｅｒｍａｌｆａｔｉ…     

Comparison of microstructure and corrosion properties of Al-Zn-Mg-Cu alloys 7150 and 7010

The influence of coarse Cu-bearing particles, matrix and subgrain boundary precipitates on the stress corrosion susceptibility of the Al-Zn-Mg-Cu alloys was investigated. The strength of 7150 alloy is about 15 MPa higher than that of 7010 alloy. The 7010 alloy exhibits higher resistance to stress corrosion cracking as compared with the 7150 alloy. The coarse Cu-bearing particles are detrimental to the resistance to stress corrosion cracking. The increase of size of matrix and subgrain boundary precipitates decreases the susceptibility of stress corrosion. The anodic dissolution and hydrogen embrittlement govern the cracking process. The severity of stress corrosion cracking is shown to be related to the coarse Cu-bearing particles, matrix and subgrain precipitates in Al-Zn-Mg-Cu alloys.     

Measurement of surface crystallinity of PAA and PAANa coatings and its effect on hydrophilicity of coatings

1　INTRODUCTIONAsanimportantwater solublemacromoleculecompound,poly (acrylicacid) (PAA)anditssaltshavebeenwidelyused[1] .Utilizingitsfinefilm form ingcapacityandhydrophilicity ,Okoroaforetal[2 ] ,andPanetal[3] developedanewhydrophilicpaintforaluminiumfin[2 ,3] .Hydrophilic paintforheat ex changerofairconditioningdemandslittlesurfacecon tactangle ,sothatcontinuoushomogeneouswaterfilmcanformeasily ,andcandrainoffcondensedwa teronthesurfaceoffintimely[4 6 ] .Hydrophilicityofcoatingsisaffec…     

The Influence of Method of Carburizing and Nitrocarburizing on the Microstructure and Properties of Tool Steels

The paper presents the results of wear and metallography tests of tool steel grades: ASTM A681, ChI2M and Ch12FS per GOST, AMS 6437E i BS X46Cr13, all surface hardened by the Carbo process (carburizing) and by the NiCar process (nitrocarburizing). The therrno-chemical treatment was conducted in powder pack for a duration of 6 h (carburizing) and for 4 h in the case of nitrocarburizing. Factors investigated were: morphology, depth and microhardness of the cases obtained, their microstructure, as well as phase composition. Wear tests were conducted by the three cylinder-cone method.Wear velocity was 0.58 m/s, unit load was 50 MPa and 400Mpa, wear path was 3470 m. Oil SAE30 was applied at the rate of 30 drops per minute.     

Test and analysis of mechanism and influential elements of axial drifting of weldment on turning rolls

0　IntroductionTheweldingturningrollsismainlyusedforweldingassemblyofcylindricalweldingcomponents.Duetode viationinfabricationandassemblyofweldingturningrollsandgeometricirregularityofweldment,theweld mentthrobsaxiallywhileitrollsontheweldingturningrolls .Itwillinfluencetheweldingqualityandbreaknor malweldingprocedure .Intheworstcases,theweld mentfallsdownfromtheweldingturningrollsandcaus esaccident.Akindofweldingturningrollsagainstaxialdriftinghasbeeninventedabroadinthemiddleof 1980andhasbee…     

Viscosity of In and In-Sballoys

The dynamic viscosity of pure In, In-1%Sb (mass fraction, so as the follows) alloy, In-55%Sb hypoeutectic alloy and In-69.5%Sb eutectic alloy was measured by using a torsional oscillation viscometer at different temperatures above liq-uidus. The experimental results show that the viscosity of these melts decreases with increasing temperature. The anomalous change of viscosity occurs at about 430 and 470℃in pure In melt. The variation of viscosity with temperature well meets exponential correlation and no anomalous change occurs in measured temperature range in the In-1%Sb alloy melt. A transition occurs at about 800℃ in both of In-55%Sb and In-69.5%Sb alloy melts. The sudden change of viscosity suggests the structure change of melts. DSC (differential scanning calorimetry) curves of In-1%Sb alloy during heating and cooling were measured, and the results show that no structural variation in In-1%Sb alloy melt was testified further. In addition, the viscosity of In melt decreases with the addition of1%S     

基于自抗扰控制技术的某舰船机械装置液压系统改进研究

由于某舰船筒盖液压系统存在非线性因素以及不确定的外部干扰,舰船筒盖开关盖过程的控制精度以及动作平稳性难以保证。为提高开关盖过程的控制精度以及平稳性,基于自抗扰控制方法开展了筒盖开关盖过程控制研究。仿真及试验结果表明：相比传统的 PID 控制,基于自抗扰控制方法提高了开关盖过程的轨迹跟踪精度,有效保证了开盖瞬间及到位瞬间的平稳性。     

基于回流能量调节的液压执行机构运动位移控制仿真研究

为提高液压执行机构控制系统响应速度,从而降低执行机构运动位移输出误差,采用超螺旋滑模控制器,并进行仿真验证。建立回流能量调节的液压执行机构简图,定义差动阀液压流量数学模型,推导出液压执行机构动力学方程式。针对传统滑模控制器进行改进,提出超螺旋滑模控制器。给出液压执行机构超螺旋滑模控制的流程,并分析控制系统的稳定性。为进一步验证超螺旋滑模控制器输出精度,采用MATLAB软件对液压执行机构运动位移进行仿真,并且与传统滑模控制器进行对比。结果表明：采用传统滑模控制器,在空载状态下,液压执行机构运动位移与期望值偏差较小,但是在负载状态下,其偏差较大;采用超螺旋滑模控制器,在空载或者负载状态下,液压执行机构运动位移与期望值偏差都较小,执行机构反应速度较快。采用超螺旋滑模控制器,可以有效降低液压执行机构滑模控制器的抖动幅度,提高运动精度。     

基于连续滑模控制的电液伺服系统轨迹追踪控制

为改善电液伺服系统的轨迹追踪精度,设计一种连续滑模控制器,用于对电液伺服系统进行轨迹追踪控制.在电液伺服系统的建模过程中,以控制阀阀芯位移为依据,得到了电磁线圈上的电压及电流方程.在液压流体的作用下,建立气缸内液压流体的流量方程.根据系统的轨迹误差,构造滑动面模型.在开环传递函数状态空间模型的基础上,建立控制律的连续方...     

80MN锻造液压机液压控制系统的研制

研制了具有等温锻功能的80 MN锻造液压机液压控制系统.针对能量损耗低和控制精度高的要求,采用了西门子S7-400 PLC与Trio控制器相结合的控制方案,PLC实现液压泵的控制、电液伺服阀的切换、工作台控制、加热与冷却系统控制、润滑系统控制及安全监测;Trio完成速度控制与平度控制的任务,获得了预期的控制结果.     

基于改进遗传算法优化的双步进电机伺服阀控制研究

针对当前电液伺服阀控制系统响应速度慢、输出误差较大的问题,采用改进遗传算法优化控制系统,并对控制效果进行仿真验证。设计了新型电液伺服阀结构,建立了电液伺服系统动力学模型,推导了液压缸流量运动方程式。采用改进遗传算法优化RBF神经网络结构,通过MATLAB软件对双步进电机伺服阀改进的控制系统进行仿真验证,并且与传统PID控制效果进行对比。结果显示:在无干扰环境中,采用传统PID控制和改进RBF神经网络控制方法都能较好地提高活塞杆运动位移输出精度;在有干扰环境中,采用传统PID控制方法,活塞杆运动位移输出的误差较大,而采用改进RBF神经网络控制方法,活塞杆运动位移输出的误差较小。采用改进RBF神经网络控制方法,能够抑制外界的干扰,从而提高双步电机伺服阀控制系统的响应速度和输出精度。     

基于改进PID控制的电液伺服系统执行器运动轨迹仿真

电液伺服系统执行器运动轨迹跟踪容易受到外界干扰,导致控制系统不稳定。为解决此问题,设计小波神经网络PID控制系统,并对控制效果进行仿真验证。建立电液伺服阀简图模型,创建阀芯运动的动力学模型,分别推导出控制阀、液压执行器和比例溢流阀动力学方程式。采用小波神经网络对传统增量式PID控制器进行改进,利用MATLAB软件对改进后的控制系统进行仿真;对比分析改进前、改进后系统液压执行器的跟踪轨迹。结果表明：液压执行器在没有受到外界波形突然干扰情况下,2种控制方法都能较好地实现轨迹跟踪;在受到外界波形突然干扰情况下,采用增量式PID控制的液压执行器运动轨迹与期望轨迹存在较大误差,采用小波神经网络PID控制的液压执行器运动轨迹与期望轨迹存在较小误差。所设计的控制系统响应速度较快,能够自适应在线调整控制参数,有效地抑制外界环境对控制系统的干扰,从而提高液压执行器运动轨迹跟踪精度     

Iterative learning control of electro-hydraulic proportional feeding system in slotting machine for metal bar cropping

A non-linear method, iterative learning control (ILC), is proposed to control the electro-hydraulic feeding process of a new slotting machine. The method attempts to acquire high precision of feeding length and trapezoid feedrate, whereas the complexity of iterative learning control algorithm does not increase much more than that of industrial PID controller. After an analysis of the two-way proportional feeding system, a non-linear dynamical mathematic model with system delay, saturation and dead-zone is developed. The computer flowrate control and the ILC controller are investigated in detail. PID controller, ILC of displacement and ILC of feedrate are compared with the dynamical model under the same desired trajectory. It is experimentally found that the proposed control scheme is more effective to improve the tracking accuracy of hydraulic feeding system of the slotting machine than that of fuzzy PID controller.     

神经网络PID控制的液压驱动主动升沉补偿预测控制研究

为了提高船舶在海面上作业时补偿精度,采用BP神经网络PID控制方法,并对船舶升沉运动输出误差进行仿真。建立船舶主动升沉补偿系统简图,分析船舶升沉运动工作原理,给出液压缸驱动传递函数。引用BP神经网络算法,采用梯度下降法对BP神经网络加权值进行修正,通过学习速率来补偿控制系统输出误差,从而实现PID控制器参数在线调节。在受到不同负载影响状况下,采用MATLAB软件对船舶升沉运动补偿精度进行仿真,并且与PID控制补偿精度进行对比。结果表明:采用PID控制器,船舶升沉运动输出误差较大,控制系统反应速度较慢;而采用BP神经网络PID控制器,船舶升沉运动输出误差较小,控制系统反应速度较快,同时,随着负载质量的增加,输出误差就会增大。采用BP神经网络PID控制系统,响应速度快,补偿精度高,提高了船舶在海面上作业定位精度。     

基于CMAC滑模控制的双马达同步技术研究

以大型起重机双卷扬系统为研究对象,针对起升过程中存在的双马达同步误差问题,提出一种基于小脑神经网络(CMAC)滑模控制方法,充分利用CMAC响应速度快及滑模变结构控制(SMC)抗干扰能力强的特点,以解决传统控制方法鲁棒性差的问题;在控制过程中采用交叉耦合控制方式,并根据液压系统动态特性将液压泵出口压力差以及吊钩的倾斜角度作为控制指标进行仿真,最后以起升工况进行实验研究。结果表明:与传统方法相比,所提出的控制策略能有效提高两个马达的同步控制精度,抗干扰能力强,满足实际工况需要。     

液压支架立柱端盖拆卸机的液压系统设计

介绍了液压支架立柱端盖拆卸机的工作原理和液压系统设计,采用可编程序控制器实现了拆卸机的动作控制,提高了系统的稳定性和灵活性。