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为使短电弧加工过程中电弧放电通道更容易、有效地建立,使其电源电气特性满足试验要求,通过分析短电弧加工脉冲电源系统的增益特性,设计出满足短电弧加工试验所需的电源反馈环路,并建立基于Matlab的电源反馈环路仿真模型,通过仿真验证了设计的电源反馈环路具有输出电压平稳,受外界干扰小,响应速度快等优点,具有良好的可行性及稳定性. 最后通过电源空载及短电弧切削加工试验,验证了设计的电源反馈环路能够满足短电弧加工试验所需要求,为短电弧加工机理研究提供了重要的技术支持. 相似文献
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<正> 0 概 述 沾化电厂1、2号除氧器环焊缝存在大量宏观裂纹和连续未焊透缺陷,在运行过程中发生多处泄漏现象,被迫降压运行,效率大大 相似文献
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《Science & Technology of Welding & Joining》2013,18(3):271-277
AbstractManual underwater welding is usually time consuming, expensive and hard to perform because of the rigorous underwater environment. Automatic underwater welding can be performed faster at less cost and with higher quality. An automatic seam tracking system for underwater flux cored arc welding has been developed. It consists of a vision sensing module, a seam recognition module, a fuzzy controller (FC) and an X–Y travel platform. The vision sensing module can capture clear seam images during welding, successfully resolving the problem of welding arc interference during underwater flux cored arc welding. The seam recognition module filters, enhances and thresholds the seam images and then recognises the seam deviation angle with a three layer back propagation neural network. The FC outputs the control parameters according to the seam deviation angle and then controls the X–Y platform to drive the torch to the centre of the seam. In this study, three different welds were considered: a straight line, a kinked straight line and an S curved line. These welds were tracked real timely during underwater flux cored arc welding. The results show that this seam tracking system can meet the requirements of the automatic underwater flux cored arc welding. 相似文献
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《Science & Technology of Welding & Joining》2013,18(3):352-357
AbstractUsing laser scanning techniques, scanning lens rotating around a laser diode and a circular laser trajectory was projected onto the surface of a weldment to detect it. Furthermore, one novel vision sensor based on the circular laser is developed. The three-dimensional (3D), circular laser based seam location sensor is investigated. On the basis of the light path system, 3D calculation algorithm is brought forward and used to locate the welded joint. After image denoise, filter, segmentation and thinning, characteristic points of the welded joint could be detected real time using a proposed vision sensor and confirmed by real experiments of butt welded joints with I groove and V groove, and lap, and fillet and ramp welded joints. The results show that circular laser based vision sensor can be used in seam locating and its calculation precision meets the requirement of seam tracking. 相似文献
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D. H. Brain 《纺织学会志》2013,104(10):493-505
An absolute method of seam-strength testing is described. The effects of fabric type and gauge length on seam strength are examined. The effects of the type of sewing thread used and various measures of thread strength on the accuracy of seam-strength prediction are also investigated. A simple method of determining the minimum loop strength of a thread is described. The efficiency of this value, corrected for one aspect of fabric construction, for seam-strength prediction is discussed. 相似文献
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Thiopave改性沥青路面力学响应研究 总被引:1,自引:0,他引:1
基于Thiopave改性沥青路面良好的高低温稳定性,采用有限元软件对典型半刚性基层沥青面层进行计算,得到不同沥青面层层底力学响应,并对计算结果进行对比研究,得到的主要结论如下:Thiopave沥青路面层底弯拉应力显著大于SBS沥青及基质沥青路面,路表轮隙中心处弯沉值小于SBS沥青及基质沥青路面;随着SEAM掺量的增加,... 相似文献
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《Science & Technology of Welding & Joining》2013,18(1):103-109
AbstractA seam tracking method is presented based on the estimation of weld position during the gas tungsten arc welding process. Kalman filtering of the weld pool images from a visual sensor is applied to compute recursively the solution to the weld position equations which are established based on an estimation of the centroid position of the weld pool images. This centroid, the position of which corresponds with the weld position, is extracted as the measurement eigenvector. The evolution of the weld position data from the weld pool images can be described through an appropriate process model, so that the weld position can be detected by applying a Kalman filter. This allows adjustment of the welding torch position in real time, which may significantly reduce processing time and promote seam tracking accuracy. Simulations and actual welding experiments have demonstrated the effectiveness of the proposed algorithm in the presence of weld pool image noise and have demonstrated the robustness of weld position detection for seam tracking. 相似文献
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Li Shuwei Jin Yixin Zhou Tianming Zhang Baolin Ning Yongqiang Jiang Hong Yuan Guang 《Journal of Electronic Materials》1995,24(11):1667-1670
The quaternary GaInAsSb alloy system with direct band gaps adjustable in wavelength from 1.7 to 4.3 μm, which may provide
the basis for emitters and detectors over this entire region, was studied. Alloys of GaInAsSb were grown lattice-matched on
GaSb substrates by metalorganic chemical vapor deposition using a conventional atmospheric pressure horizontal reactor. The
properties of the GalnAsSb alloys were characterized by single crystal x-ray rocking curves, the double crystal x-ray rocking
curves, the photoluminescence and infrared absorption. A preliminary study of the capabilities of scanning electron acoustic
microscopy in the characterization of GaInAsSb alloy has been made, some observations are briefly compared with scanning electron
microscopy. 相似文献