Hot compression behavior of Al6061/Al2O3nanocomposite was investigated in the temperature range of350-500°C andthe strain rate range of0.0005-0.5s-1,in order to determine the optimum conditions for the hot workab...Hot compression behavior of Al6061/Al2O3nanocomposite was investigated in the temperature range of350-500°C andthe strain rate range of0.0005-0.5s-1,in order to determine the optimum conditions for the hot workability of nanocomposite.Theactivation energy of285kJ/mol for the hot compression test is obtained by using hyperbolic sine function.By means of dynamicmaterial model(DMM)and the corresponding processing map,safe zone for the hot workability of AA6061/Al2O3is recognized attemperature of450°C and strain rate of0.0005s-1and at temperature of500°C and the strain rate range of0.0005-0.5s-1,with themaximum power dissipation efficiency of38%.Elongated and kinked grains are observed at400°C and strain rate of0.5s-1due tothe severe deformation.展开更多
In order to utilize integrated passive technology in printed circuit boards （PCBs）, manufacturing processing for integrated resistors by lamination method was investigated. Integrated resistors fabricated from Ohmeg...In order to utilize integrated passive technology in printed circuit boards （PCBs）, manufacturing processing for integrated resistors by lamination method was investigated. Integrated resistors fabricated from Ohmega technologies in the experiment were 1 408 pieces per panel with four different patterns A, B, C and D and four resistance values of 25, 50, 75 and 100 fL Six panel per batch and four batches were performed totally. The testing was done for 960 pieces of integrated resistors randomly selected with the same size. The value distribution ranges and the relative standard deviation （RSD） show that the scatter degree of the resistance decreases with the resistor size increasing and/or with the resistance increasing. Patterns D with resistance of 75 and 100% for four patterns have the resistance value variances less than 10%. Patterns C and D with resistance of 100 Ω have the manufacturing tolerance less than 10%. The process capabilities are from about 0.6 to 1.6 for the designed testing patterns, which shows that the integrated resistors fabricated have the potential to be used in multilayer PCBs in the future.展开更多
We report about current work which is aimed to improve the adhesion of melt processable elastomers onto relevant reinforcement materials by means of short wave UVC （ultraviolet C） light. Results of laboratory tests ...We report about current work which is aimed to improve the adhesion of melt processable elastomers onto relevant reinforcement materials by means of short wave UVC （ultraviolet C） light. Results of laboratory tests regarding UVC surface activation ofpolyamide fiber materials in air using low-pressure mercury lamps with 185 nm and 254 nm emissions are shown. The effect of irradiation on fiber strength was studied to find out suitable process parameters for providing the UVC treatment efficient but as gentle as possible to avoid negative effects on reinforcement properties. Application of a laboratory process for UVC pretreatment leads to significantly increased adhesion strength between the fibers and the melt processable elastomers on the base of TPA （polyamide） respectively TPU （polyurethane）.展开更多
A mobile in-situ testing equipment used to detect geotechnical thermophysical properties was developed. The equipment is composed of a heat pump, frequency pumps, an electric tee joint regulator valve, some sensors, a...A mobile in-situ testing equipment used to detect geotechnical thermophysical properties was developed. The equipment is composed of a heat pump, frequency pumps, an electric tee joint regulator valve, some sensors, an electric control system, data acquisition and control system, which can do tests under the condition of extracting and storing subsurface heat. Applying the line source and the cylinder source heat transfer model, and combining the parameters estimation, the average thermophysieal property parameters of rock and soil will be calculated, which provides the basis for designing the ground source heat pump systems.展开更多
The mechanism of ultrasonic vibration honing Nd-Fe-B has been briefly elaborated after the introduction of the strategic significance of processing Nd-Fe-B. Based on the formation principle of Scanning Electrtmic Micr...The mechanism of ultrasonic vibration honing Nd-Fe-B has been briefly elaborated after the introduction of the strategic significance of processing Nd-Fe-B. Based on the formation principle of Scanning Electrtmic Microscope （SEM）, and at the examination with the aid of SEM to the ultrasonic vibration honing Nd-Fe-B material＇s superficial microscopic topography, the paper discusses the new processing nechanism according to the SEM examination picture. The research indicates that as a result of supersonic high frequency vibration, the path of the abrasion extends at the same time, and the supersonic cavitation effect forms the intense shock-wave, knpacting Nd-Fe-B material＇s intemal surface, providing the supersonic energy for the superticial abrasive dust＇s dimination, which directly explain that the honing processing efficiency is enhanced, and the processing surface roughness is high.展开更多
Microchannel heat sinks constitute an innovative cooling technology for the removal of a large amount of heat from a small area and are suitable for electronics cooling.In the present work,Tool Steel D2 grade milling ...Microchannel heat sinks constitute an innovative cooling technology for the removal of a large amount of heat from a small area and are suitable for electronics cooling.In the present work,Tool Steel D2 grade milling slitting saw type plain milling cutter is fabricated The microchannels are machined in aluminum work pieces to form the microchannel heat sink using the fabricated milling cutter in an horizontal milling machine.A new experimental set-up is fabricated to conduct the tests on the microchannel heat sink.The heat carried by the water increases with mass flow rate and heat input.The heat transfer coefficient and Nusselt number increases with mass flow rate and increased heat input.The pressure drop increases with Reynolds number and decreases with input heat.The friction factor decreases with Reynolds number and decreases with input heat.The thermal resistance decreases with pumping power and decreases with input heat.展开更多
文摘Hot compression behavior of Al6061/Al2O3nanocomposite was investigated in the temperature range of350-500°C andthe strain rate range of0.0005-0.5s-1,in order to determine the optimum conditions for the hot workability of nanocomposite.Theactivation energy of285kJ/mol for the hot compression test is obtained by using hyperbolic sine function.By means of dynamicmaterial model(DMM)and the corresponding processing map,safe zone for the hot workability of AA6061/Al2O3is recognized attemperature of450°C and strain rate of0.0005s-1and at temperature of500°C and the strain rate range of0.0005-0.5s-1,with themaximum power dissipation efficiency of38%.Elongated and kinked grains are observed at400°C and strain rate of0.5s-1due tothe severe deformation.
基金Project(041010) supported by Start-Up Foundation of Northwest University,ChinaProject(UIT/39) supported by University-Industry Collaboration Program from the Innovation and Technology Fund of Hong Kong,China
文摘In order to utilize integrated passive technology in printed circuit boards （PCBs）, manufacturing processing for integrated resistors by lamination method was investigated. Integrated resistors fabricated from Ohmega technologies in the experiment were 1 408 pieces per panel with four different patterns A, B, C and D and four resistance values of 25, 50, 75 and 100 fL Six panel per batch and four batches were performed totally. The testing was done for 960 pieces of integrated resistors randomly selected with the same size. The value distribution ranges and the relative standard deviation （RSD） show that the scatter degree of the resistance decreases with the resistor size increasing and/or with the resistance increasing. Patterns D with resistance of 75 and 100% for four patterns have the resistance value variances less than 10%. Patterns C and D with resistance of 100 Ω have the manufacturing tolerance less than 10%. The process capabilities are from about 0.6 to 1.6 for the designed testing patterns, which shows that the integrated resistors fabricated have the potential to be used in multilayer PCBs in the future.
文摘We report about current work which is aimed to improve the adhesion of melt processable elastomers onto relevant reinforcement materials by means of short wave UVC （ultraviolet C） light. Results of laboratory tests regarding UVC surface activation ofpolyamide fiber materials in air using low-pressure mercury lamps with 185 nm and 254 nm emissions are shown. The effect of irradiation on fiber strength was studied to find out suitable process parameters for providing the UVC treatment efficient but as gentle as possible to avoid negative effects on reinforcement properties. Application of a laboratory process for UVC pretreatment leads to significantly increased adhesion strength between the fibers and the melt processable elastomers on the base of TPA （polyamide） respectively TPU （polyurethane）.
基金Supported by Special Project of Public Sector Funding for Scientific Research,Ministry of Land and Resources,China(No.200811066)
文摘A mobile in-situ testing equipment used to detect geotechnical thermophysical properties was developed. The equipment is composed of a heat pump, frequency pumps, an electric tee joint regulator valve, some sensors, an electric control system, data acquisition and control system, which can do tests under the condition of extracting and storing subsurface heat. Applying the line source and the cylinder source heat transfer model, and combining the parameters estimation, the average thermophysieal property parameters of rock and soil will be calculated, which provides the basis for designing the ground source heat pump systems.
基金supported by The Natural Science Foundation of China(50975265)The Natural Science Foundation of Shanxi Province of China(2007011071)Program for the Top Young Academic Leaders of Higher Learning Institutions of Shanxi(20080205ZX)
文摘The mechanism of ultrasonic vibration honing Nd-Fe-B has been briefly elaborated after the introduction of the strategic significance of processing Nd-Fe-B. Based on the formation principle of Scanning Electrtmic Microscope （SEM）, and at the examination with the aid of SEM to the ultrasonic vibration honing Nd-Fe-B material＇s superficial microscopic topography, the paper discusses the new processing nechanism according to the SEM examination picture. The research indicates that as a result of supersonic high frequency vibration, the path of the abrasion extends at the same time, and the supersonic cavitation effect forms the intense shock-wave, knpacting Nd-Fe-B material＇s intemal surface, providing the supersonic energy for the superticial abrasive dust＇s dimination, which directly explain that the honing processing efficiency is enhanced, and the processing surface roughness is high.
文摘Microchannel heat sinks constitute an innovative cooling technology for the removal of a large amount of heat from a small area and are suitable for electronics cooling.In the present work,Tool Steel D2 grade milling slitting saw type plain milling cutter is fabricated The microchannels are machined in aluminum work pieces to form the microchannel heat sink using the fabricated milling cutter in an horizontal milling machine.A new experimental set-up is fabricated to conduct the tests on the microchannel heat sink.The heat carried by the water increases with mass flow rate and heat input.The heat transfer coefficient and Nusselt number increases with mass flow rate and increased heat input.The pressure drop increases with Reynolds number and decreases with input heat.The friction factor decreases with Reynolds number and decreases with input heat.The thermal resistance decreases with pumping power and decreases with input heat.
