逆变器弧焊电源

本文对逆变器弧焊电源进行了阐述，介绍了高频变换技术在逆变器弧焊电源中的应用。     

模糊逻辑控制在焊接中的应用进展

介绍了近年来模糊逻辑在焊缝跟踪、焊接电源和焊接质量控制中的应用技术进展，探讨了模糊逻辑在弧焊过程控制中的应用途径．     

05CuPCrNi钢等离子弧焊焊接接头的组织与力学性能

 为了研究等离子弧焊在焊接薄板耐候钢时的优越性,对2 mm厚 05CuPCrNi耐大气腐蚀钢分别进行等离子弧焊与MAG焊(熔化极活性气体保护电弧焊)对接焊接,然后对焊接接头分别进行拉伸、弯曲、金相、硬度等试验,通过与MAG焊焊接接头的组织与力学性能对比,结果表明,与MAG焊相比,等离子弧焊时05CuPCrNi耐大气腐蚀钢焊接接头强度相对提高约6%,焊接接头组织为更均匀且细小的铁素体＋珠光体,并无MAG焊中出现的粗大块状铁素体及贝氏体,焊接热影响区较小,焊接接头弯曲性能良好,硬度值及硬度分布情况与MAG相近且无软化现象。     

铝合金激光—电弧双面焊接中“双弧”形成机理探讨

铝合金激光焊接技术存在着一定难度,探讨铝合金激光-电弧双面焊接中"双弧"的形成机理。通过了解铝合金激光焊接发展现状,获得其焊接方法,得出铝合金激光的焊接中存在接头产生焊缝裂纹和接头软化等难点。分别研究铝合金双面双弧非对称焊接、对称焊接,得到-电弧双面焊接中"双弧"形成机理。反面碳弧气刨和检验等焊接程序,被双弧焊取消了,在一定程度上提升了焊接效率,这一焊接方法是高效节能的工艺技术,为提高焊件质量和力学效果提供可靠的参考依据。     

弧焊逆变器的应用与发展现状

本文结合工厂实际 ,通过原理分析及参数比较 ,对弧焊逆变器的应用与发展现状进行剖析 ,提出相应观点。     

钛薄板材的脉冲钨极氩弧焊

1前言钛材由于其高的比强度和优良的角蚀性而广泛的应用于石油化工、航空航天、兵器、电子、医疗等行业．随着钛工业的发展，其焊接技术也有了一个大的发展．现常用的焊接方法有电子束焊，镇极氢孤焊、熔化极氢弧焊，等离子弧焊和舒焊等．而钛的薄板材焊接，采用常规焊法易出现焊穿、变形大、性能不稳定、焊速低等现象．为此，本文采用脉冲钨极氢弧焊，探讨了钛薄板材的焊接性能．2试验方法11母材选用0．4tnlll厚的TAI退火板，其化学成分符合国标．2．2试样制备将巧板材沿轧制方向和横向切割成门01llln“85Inln“队4mln的试扳后进行焊接，…     

大型电机转子背套焊接工艺探索与实践

介绍了一种大型电机转子背套焊接方法——经改进的磷铜焊条手弧焊，其具有焊接质量好，耗时少，推广价值高等显著特点，经实践检验，效果明显。     

高性能耐火耐候建筑用钢焊接性能研究

对武钢研制的高性能耐火耐候建筑用钢WGJ510C2的焊接性能，包括最高硬度、斜Y坡口、手弧焊焊接接头力学性能和不同线能量下模拟焊接热影响区（CGHAZ）的组织结构进行了研究，试验结果表明，该钢具有低的冷纹敏感性，其焊接性能优良，并能承受大线能量焊接。     

高性能耐火耐候建筑用钢焊接性能及其应用研究

对武钢研制的高性能耐火耐候建筑用钢WGJ510C2的焊接性能，包括最高硬度、斜Y坡口、手弧焊焊接接头力学性能和不同线能量下模拟焊接热影响区(CGHAZ)的组织结构及该钢的实际应用进行了研究。试验结果表明：该钢具有低的冷裂纹敏感性，其焊接性能优良，并能承受大线能量焊接。     

SCR—MOSFET双逆变交流方波弧焊电源的研究

对SCR-MOSFET双逆变交流方波弧焊电源的工作原理做了详细介绍,并探讨了场效应管逆变器的若干问题。包括逆变器的动态数学分析,场效应管并联均流及峰值电压抑制等问题,并对其工艺试验结果进行了分析。     

旋吹袋式除尘器及戈尔玻纤覆膜滤料技术在热电厂除尘系统中的应用

马钢掺烧高炉煤气燃煤锅炉的烟气处理系统中，采用了高效的低压脉冲旋转反吹袋式除尘器。并大胆选用了戈尔玻纤覆膜滤料，获得了较好效果，开创了应用先例。     

Correlation of microstructure and fracture toughness in high-chromium white iron hardfacing alloys

A correlation is made of microstructure and fracture toughness in hypereutectic high-chromium white iron hardfacing alloys. In order to investigate the matrix effect of these alloys, in particular, four different matrices such as pearlite, austenite, and a mixture of pearlite and austenite were employed by changing the ratio of Mn/Si, while the total volume fraction of carbides was fixed. The hardfacing alloys were deposited twice on a mild steel plate by the self-shielding flux-cored arc-welding method. Fracture toughness was increased by increasing the volume fraction of austenite in the matrix, whereas hardness and abrasion resistance were nearly constant.In situ observation of the fracture process showed that cracks initiated at large primary carbides tended to be blocked at the austenitic matrix. This suggested that fracture toughness was controlled mainly by the amount of austenite in the matrix, thereby yielding the better toughness in the hardfacing alloy having the austenitic matrix. Considering both abrasion resistance and fracture toughness, therefore, the austenitic matrix was preferred for the high-chromium white iron hardfacing alloys.     

3000t热矫直机辊系更换的优化与改造

分析辊系更换现状,查找影响辊系更换效率的因素,通过系统地优化辊系更换方案,提升辊系更换效率,大幅缩短了换辊时间。     

Oligodendrocytes from forebrain are highly vulnerable to AMPA/kainate receptor-mediated excitotoxicity

STATEMENT OF PROBLEM: Titanium and its alloys are more commonly used in prosthodontics and welding has become the most common modality for their joining. Studies on the welding of titanium and its alloys have not quantified this value, though its importance has been suggested. PURPOSE: This study compared the strength and properties of the joint achieved at various butt joint gaps by the arc-welding of cast Ti-6Al-4V alloy tensile bars in an argon atmosphere. MATERIAL AND METHODS: Forty of 50 specimens were sectioned and welded at four gaps. All specimens underwent tensile testing to determine ultimate tensile strength and percentage elongation, then oxygen analysis and scanning electron microscopy. RESULTS: As no more than 3 samples in any group of 10 actually fractured in the weld itself, a secondary analysis that involved fracture location was initiated. There were no differences in ultimate tensile strength or percentage elongation between specimens with weld gaps of 0.25, 0.50, 0.75, and 1.00 mm and the as-cast specimens. There were no differences in ultimate tensile strength between specimens fracturing in the weld and those fracturing in the gauge in welded specimens; however, as-cast specimens demonstrated a higher ultimate tensile strength than welded specimens that fractured in the weld. Specimens that fractured in the weld site demonstrated less ductility than those that fractured in the gauge in both welded and as-cast specimens, as confirmed by scanning electron microscopy examination. The weld wire showed an oxygen scavenging effect from the as-cast parent alloy. CONCLUSIONS: The effects of the joint gap were not significant, whereas the characteristics of the joint itself were, which displayed slightly lower strength and significantly lower ductility (and thus decreased toughness). The arc-welding of cast titanium alloy in argon atmosphere appears to be a reliable and efficient prosthodontic laboratory modality producing predictable results, although titanium casting and joining procedures must be closely controlled to minimize heat effects and oxygen contamination.     

Action potential classifiers: a functional comparison of template matching, principal components analysis and an artificial neural network

Multiunit neural activity occurs often in electrophysiological studies when utilizing extracellular electrodes. In order to estimate the activity of the individual neurons each action potential in the recording must be classified to its neuron of origin. This paper compares the accuracy of two traditional methods of action potential classification--template matching and principal components--against the performance of an artificial neural network (ANN). Both traditional methods use averages of action potential shapes to form their corresponding classifiers while the artificial neural network 'learns' a nonlinear relationship between a set of prototype action potentials and assigned classes. The set of prototypic action potentials and the assigned classes is termed the training set. The training set contained action potentials from each class which exhibited the full range of amplitude variability. The ANN provided better classification results and was more robust in analysis of across-animal data sets than either of the traditional action potential classification methods.     

连铸结晶器电液伺服系统的研究

介绍了电液伺服驱动连铸结晶器振动系统,建立了系统的数学模型,进行了计算机仿真和现场运行.与传统的结晶器振动装置相比,该系统能根据连铸工艺要求改变波形,在线改变振动频率和振幅等参数,有效地提高了控制精度和铸坯表面质量.     

基于改进CV模型的金相图像分割

对金相图像进行快速精确分割是金相晶粒评级的关键步骤,利用传统Chan-Vese（CV）模型很难将晶粒精确地提取出来.为了更加精确地对金相图像进行分割,提出一种基于改进CV模型的金相图像分割方法.初始化水平集函数,对曲线内外两部分分别计算其倒数坎贝拉距离,并将该距离的大小作为拟合中心的权重系数,有效抑制了噪声点对区域拟合中心准确性的影响;引入指数熵自适应调节曲线内外能量权重,减少固定能量权重对曲线演化的影响;同时加入距离规范项以避免水平集函数的重新初始化,加速该模型的收敛.实验结果表明,与传统CV模型、测地线活动轮廓模型、距离规范项的水平集模型以及偏置场修正水平集模型相比,所提方法分割出的金相图像更加精确,分割效率较高且模型收敛性较好.      

Lung reduction surgery: a true advance?

Occupational asthma is one of the commonest occupational lung diseases. This is a case of asthma related to arc-welding in a shipyard. Serial peak expiratory flow rate readings were taken with and without exposure to the welding process. The results showed that the patient had occupational asthma from welding. This case report serves to remind us of the need to ask every adult with asthma for their occupational history. It emphasises the need for early diagnosis and removal from the cause of asthma. A delay in diagnosis may lead to non-specific bronchial reactivity and persistence of symptoms.     

钢铁流程固废资源化利用逆向供应链体系探讨

 以“减量化 再利用 再循环”的 3R 原则为指导，以实现钢铁流程固体废弃物再利用为目标，设计了钢铁流程固体废弃物资源化利用逆向供应链体系。结合各类固体废弃物的成分特性，设定有价元素为新资源，构建了钢铁流程固体废弃物资源化利用逆向供应链组合方案，并配置了流程自循环、外部利用和产物升级的梯级实施路径。为了达到逆向供应链操作过程的动态有序、协同连续和集约高效，建议引入固体废弃物全生命周期绿色化管理体系，并贯穿到固体废弃物资源化利用逆向供应链组合方案的初步规划与具体实施中，这将有利于降低企业固体废弃物环境管理投入成本和取得优良的钢铁全流程绿色化效果。     

基于模糊神经网络的PID钢丝电接触运动加热温度控制

对于非线性、时变性的工业对象,采用模糊神经网络整定PID参数,提高了传统PID控制的自适应能力。仿真结果及其应用表明,其控制性能优于一般PID的控制性能。