Some measurement methods of wafer bonding strength were summarized. The principle of crack-opening method was analyzed and the system parameters and function were presented. A design idea was used to develope the test...
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Some measurement methods of wafer bonding strength were summarized. The principle of crack-opening method was analyzed and the system parameters and function were presented. A design idea was used to develope the testing system. Some key technique modules including precision positioning, micro-vision, IR measurement and control system are studied respectively. A wafer bonding strength measurement system are designed based on integrating all the modules. Finally, the feasibility of the system is tested by some contrast experiments with different bonding samples.
In this paper, the micromanipulation system for the MEMS assembly is constructed. An improved focus measure and clamping strategy are proposed for the assembly of the MEMS. The focus measure is used to focusing the mi...
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In this paper, the micromanipulation system for the MEMS assembly is constructed. An improved focus measure and clamping strategy are proposed for the assembly of the MEMS. The focus measure is used to focusing the miniaturized gear and clamp images, and the clamping strategy is used to obtain the miniaturized gear Z-directional information between the gear and clam and assemble the planetary gears. Experiments show the good performance of the algorithm and strategy.
In recent years, Internet-scale worm incidents occurred many times. People wonder at the speediness of the worm spread and the severe damage to the Internet. So people began to find methods to detect worms as quickly ...
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In recent years, Internet-scale worm incidents occurred many times. People wonder at the speediness of the worm spread and the severe damage to the Internet. So people began to find methods to detect worms as quickly as possible. The paper first describes a worm behavior and propagation model. And then based on it, a new approach for early detection of Internet worms is proposed. This approach determines whether a worm incident has occurred by the change of the computers' connection degree. The approach is proved to be effective on early detection of unknown worms by experiments.
A dual-beam electronic speckle pattern interferometry (ESPI) system was adopted to get speckle patterns for the measurement of welding dynamic displacement fields. The mathematical model of this system was described, ...
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A dual-beam electronic speckle pattern interferometry (ESPI) system was adopted to get speckle patterns for the measurement of welding dynamic displacement fields. The mathematical model of this system was described, based on which methods of the ESPI pattern image processing were discussed. Gray transformation and histogram equalization were used to enhance the contrast of speckle patterns. A discrete cosine image processing method was carried out and an exponent low-pass filter was chosen to reduce multiplicative noise in speckle patterns. Speckle grain noise can be eliminated effectively after these processes.
The high-speed camera system and data acquisition system of welding parameters were created in tandem MIG welding of high strength aluminum alloy. The experiments were carried out in order to obtain the photos of drop...
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The high-speed camera system and data acquisition system of welding parameters were created in tandem MIG welding of high strength aluminum alloy. The experiments were carried out in order to obtain the photos of droplet transfer under different welding parameters in pulsed mode. The droplet transfer mode of “one pulse one droplet” becomes the preferred selection during welding process because of its stable procedure and sound weld form. The parameter ranges for corresponding transfer mode were experimentally achieved, among which the stable droplet transfer mode of “one pulse one droplet” can be realized. These efforts brave the way for control weld heat input and weld formation in the future.
The plasma is an important characteristic during laser keyhole welding processing;the weld quality is related to the shape and stability of plasma directly. By using a CCD sensor system, the optical emission of the pl...
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ISBN:
(纸本)0912035765
The plasma is an important characteristic during laser keyhole welding processing;the weld quality is related to the shape and stability of plasma directly. By using a CCD sensor system, the optical emission of the plasma was investigated. It was found that the gas in the laser path would be cascade ionized due to the effects of the thermal lens and reflection of molten pool metal, which cause the plasma abnormally expanded and ejected. As a result, welding process was disturbed and penetration depth was in unstable state. The experimental results also indicated that, during the stable welding process, the dimensions of the plasma were corresponding to the weld depth on some degree, this can be used to monitoring the stability of laser welding process.
Associate Editor in Chief Marc Donner examines the Witty Worm and what its existence might mean for the future of the software development infrastructure.
Associate Editor in Chief Marc Donner examines the Witty Worm and what its existence might mean for the future of the software development infrastructure.
作者：
Yiyu QIAN Feng GAO Fengjiang WANG Hui ZHAOState Key Laboratory of Advanced Welding Production Technology
Harbin Institute of Technology Harbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China
In the applications of heat exchangers, the fin efficiency of heat transfer is the key issue. Thermal distribution withinthe brazed joints in heat exchanger under loading conditions is investigated in this paper. Simu...
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In the applications of heat exchangers, the fin efficiency of heat transfer is the key issue. Thermal distribution withinthe brazed joints in heat exchanger under loading conditions is investigated in this paper. Simulated results showedthat the thermal distribution at the brazed joint zone is related to not only the geometry of the fin and tube, butalso the brazed joint topology. A poor brazed joint will result in very poor heat transfer. Thermal contact resistanceis adopted to analyze the fin heat efficiency.
According to specifications for Welding Procedure Qualification of ASME IX Section and Chinese code, JB 4708 2000, a software package for managing welding documents has been rebuilt. Consequently, the new software pa...
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According to specifications for Welding Procedure Qualification of ASME IX Section and Chinese code, JB 4708 2000, a software package for managing welding documents has been rebuilt. Consequently, the new software package can be used in a Limited Area Network (LAN) with 4 different levels of authorities for different users. Therefore, the welding documents, including DWPS (Design for Welding Procedure Specifications), PQRs (Procedure Qualification Records) and WPS (Welding Procedure Specifications) can be shared within a company. At the same time, the system provides users various functions such as browsing, copying, editing, searching and printing records, and helps users to make decision of whether a new PQR test is necessary or not according to the codes above as well. Furthermore, super users can also browse the history of record modification and retrieve the records when needed.
In this paper, various laser scanning methods were presented. A new and promising laser scanning method was discussed, and the principle of the laser scanning reflow system was illustrated. With this system, laser sca...
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ISBN:
(纸本)0780381688
In this paper, various laser scanning methods were presented. A new and promising laser scanning method was discussed, and the principle of the laser scanning reflow system was illustrated. With this system, laser scanning reflow experiments of PBGA solder balls were carried out. Results of experiments showed that laser scanning reflow of PBGA solder balls could be realized with a wide parameter window. The formation of the solder bump is strongly influenced by laser input energy. With proper laser input energy, solder bumps with a smooth surface, high shear strength and fine microstructure could be obtained.
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