The Seebeck coefficient is determined from silicon microchannel plates （Si MCPs） prepared by photo- assisted electrochemical etching at room temperature （25 ℃）. The coefficient of the sample with a pore size of 5...The Seebeck coefficient is determined from silicon microchannel plates （Si MCPs） prepared by photo- assisted electrochemical etching at room temperature （25 ℃）. The coefficient of the sample with a pore size of 5 × 5μm^2, spacing of 1 μm and thickness of about 150 μm is -852μV/K along the edge of the square pore. After doping with boron and phosphorus, the Seebeck coefficient diminishes to 256 μV/K and -117 μV/K along the edge of the square pore, whereas the electrical resistivity values are 7.5 × 10^-3 Ω·cm and 1.9 × 10^-3 Ω·cm, respectively. Our data imply that the Seebeck coefficient of the Si MCPs is related to the electrical resistivity and is consistent with that of bulk silicon. Based on the boron and phosphorus doped samples, a simple device is fabricated to connect the two type Si MCPs to evaluate the Peltier effect. When a proper current passes through the device, the Peltier effect is evidently observed. Based on the experimental data and the theoretical calculation, the estimated intrinsic figure of merit ZT of the unicouple device and thermal conductivity of the Si MCPs are 0.007 and 50 W/（m.K）, respectively.展开更多
The asymmetric thermo-physical mechanism of the resistance spot welding technique with intermediate frequency(2 kHz)and direct current(RSWIFDC)on the high strength aluminum(Al)alloy TL091 was studied here in view of t...The asymmetric thermo-physical mechanism of the resistance spot welding technique with intermediate frequency(2 kHz)and direct current(RSWIFDC)on the high strength aluminum(Al)alloy TL091 was studied here in view of the Peltier effect.On the basis of the analysis of the electrode cap surface erosion state and the shape-position of the nugget,it was concluded that asymmetric thermo-physical phenomenon occurred on both ends of the nugget,and even had an influence upon the shape-forming coefficient and the vertical position deviation of the nugget,and the erosion degree of the electrode caps.In this work,the relative thermo-physical model of the welding was established combined with the Peltier effect and the spot welding characteristics.Accordingly the relative welding phenomena,such as nugget center deviation and different erosion degree of the electrode cap surface,was explained clearly using the model related with the Peltier effect for the first time.This model provides important theoretical basis for future study and application of Al alloy spot welding,based on which,effective works may be done to promote the quality of the Al alloy welded joints and to obtain favorable control upon parameters of Al alloy welding for electrode caps.展开更多
【目的】为解决传统蒸馏装置蒸馏液体时的高能耗和低能效比问题,提出一种采用循环水作为冷却介质的耦合热电制冷器(thermo electric cooler,TEC)的蒸馏装置。【方法】首先选取甲醇作为目标液体进行试验验证;然后考察TEC冷热端的热力学...【目的】为解决传统蒸馏装置蒸馏液体时的高能耗和低能效比问题,提出一种采用循环水作为冷却介质的耦合热电制冷器(thermo electric cooler,TEC)的蒸馏装置。【方法】首先选取甲醇作为目标液体进行试验验证;然后考察TEC冷热端的热力学参数在不同输入电压下对系统蒸馏速率及能效比的影响。【结果】使用4片型号为TEC1-12706的制冷片,当循环水流速为40 L/h、电压为15 V时,甲醇的馏出速率最大值为18.7 g/min,此时系统的能效比最高为285.5%。【结论】本研究结果可为传统蒸馏装置能效比的提升提供一些参考。展开更多
基金Project supported by the Shanghai Fundamental Key Project(No.10JC1404600)the Shanghai Natural Science Foundation(No. 11ZR1411000)+3 种基金the Innovation Program of Shanghai Municipal Education Commission(No.09ZZ46)the International Collaboration Project(No.10520704400)the National Natural Science Foundation of China(Nos.60990312,61076060,61176108)the City University of Hong Kong Strategic Research Grant(SRG)(No.7008009).
文摘The Seebeck coefficient is determined from silicon microchannel plates （Si MCPs） prepared by photo- assisted electrochemical etching at room temperature （25 ℃）. The coefficient of the sample with a pore size of 5 × 5μm^2, spacing of 1 μm and thickness of about 150 μm is -852μV/K along the edge of the square pore. After doping with boron and phosphorus, the Seebeck coefficient diminishes to 256 μV/K and -117 μV/K along the edge of the square pore, whereas the electrical resistivity values are 7.5 × 10^-3 Ω·cm and 1.9 × 10^-3 Ω·cm, respectively. Our data imply that the Seebeck coefficient of the Si MCPs is related to the electrical resistivity and is consistent with that of bulk silicon. Based on the boron and phosphorus doped samples, a simple device is fabricated to connect the two type Si MCPs to evaluate the Peltier effect. When a proper current passes through the device, the Peltier effect is evidently observed. Based on the experimental data and the theoretical calculation, the estimated intrinsic figure of merit ZT of the unicouple device and thermal conductivity of the Si MCPs are 0.007 and 50 W/（m.K）, respectively.
文摘The asymmetric thermo-physical mechanism of the resistance spot welding technique with intermediate frequency(2 kHz)and direct current(RSWIFDC)on the high strength aluminum(Al)alloy TL091 was studied here in view of the Peltier effect.On the basis of the analysis of the electrode cap surface erosion state and the shape-position of the nugget,it was concluded that asymmetric thermo-physical phenomenon occurred on both ends of the nugget,and even had an influence upon the shape-forming coefficient and the vertical position deviation of the nugget,and the erosion degree of the electrode caps.In this work,the relative thermo-physical model of the welding was established combined with the Peltier effect and the spot welding characteristics.Accordingly the relative welding phenomena,such as nugget center deviation and different erosion degree of the electrode cap surface,was explained clearly using the model related with the Peltier effect for the first time.This model provides important theoretical basis for future study and application of Al alloy spot welding,based on which,effective works may be done to promote the quality of the Al alloy welded joints and to obtain favorable control upon parameters of Al alloy welding for electrode caps.
基金supported by the National Natural Science Foundation of China(No.21973086 and No.21633006)the Ministry of Education of China(111 Project Grant No.B18051)+1 种基金the Fundamental Research Funds for the Central Universities(No.WK2060000018)The computational resources are provided by the Supercomputing Center of University of Science and Technology of China.
