Conventional refrigeration processes release ammonia and freon into the atmosphere,which results in global warming.These problems may be overcome by using thermoelectric modules because of the absence of coolants or r...Conventional refrigeration processes release ammonia and freon into the atmosphere,which results in global warming.These problems may be overcome by using thermoelectric modules because of the absence of coolants or refrigerants in these systems.However,the cooling performances of such modules are relatively small in comparison to those of conventional refrigerators.In this paper,the working principles of thermoelectric modules are discussed together with a review of different relevant aspects,namely:the thermoelectric materials,and their mechanical properties used to build thermoelectric devices,different types of thermoelectric devices available on the market,mathematical modeling of thermoelectric materials,and various applications of thermoelectric materials in different fields.展开更多
Based on the phenomenon of curvature-induced doping in graphene we propose a class of Peltier cooling devices, produced by geometrical effects, without gating. We show how a graphene nanorib- bon laid on an array of c...Based on the phenomenon of curvature-induced doping in graphene we propose a class of Peltier cooling devices, produced by geometrical effects, without gating. We show how a graphene nanorib- bon laid on an array of curved nano cylinders can be used to create a targeted and tunable cooling device. Using two different approaches, the Nonequilibrium Green＇s Function （NEGF） method and experimental inputs, we predict that the cooling kW/cm2, on par with the best known techniques power of such a device can approach the order of using standard superlattice structures. The structure proposed here helps pave the way toward designing graphene electronics which use geometry rather than gating to control devices.展开更多
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
In this paper, operator-based nonlinear water temperature control for a group of three connected microreactors actuated by Peltier devices is proposed. To control the water temperature of tube in the microreactor, the...In this paper, operator-based nonlinear water temperature control for a group of three connected microreactors actuated by Peltier devices is proposed. To control the water temperature of tube in the microreactor, the temperature change of aluminum effects is considered. Therefore, the temperature change of aluminum becomes the part of an input of the tube. First, nonlinear thermal models of aluminum plates and tubes that structure the microreactor are obtained. Then, an operator based nonlinear water temperature control system for the microreactor is designed. Finally, the effectiveness of the proposed models and methods is confirmed by simulation and experimental results.展开更多
文摘Conventional refrigeration processes release ammonia and freon into the atmosphere,which results in global warming.These problems may be overcome by using thermoelectric modules because of the absence of coolants or refrigerants in these systems.However,the cooling performances of such modules are relatively small in comparison to those of conventional refrigerators.In this paper,the working principles of thermoelectric modules are discussed together with a review of different relevant aspects,namely:the thermoelectric materials,and their mechanical properties used to build thermoelectric devices,different types of thermoelectric devices available on the market,mathematical modeling of thermoelectric materials,and various applications of thermoelectric materials in different fields.
基金It is a pleasure to thank Y. Chen, E.- A. Kim, and Y. L. Loh for conversations. W. J. Li would like to thank Vinh Quang Diep and Seokmin Hong for many useful discussions. W. J. Li, D. X. Yao, and E. W. Carlson acknowledge support from Research Corporation for Science Advancement and NSF Grant No. DMR 11-06187. W. J. Li acknowledges support from the Purdue Research Foundation. D. X. Yao aeknowledgcs support from the National Basic Research Program of China （No. 2012CB821400）, the National Natural Science Foundation of China （Grant Nos. 11074310 and 11275279）, Research Fund for the Doctoral Program of Higher Education of China （20110171110026）, and NCET-11-0547. EWC thanks Ecole Superieure de Physique et de Chimie Industrielles （ESPCI） for hospitality.
文摘Based on the phenomenon of curvature-induced doping in graphene we propose a class of Peltier cooling devices, produced by geometrical effects, without gating. We show how a graphene nanorib- bon laid on an array of curved nano cylinders can be used to create a targeted and tunable cooling device. Using two different approaches, the Nonequilibrium Green＇s Function （NEGF） method and experimental inputs, we predict that the cooling kW/cm2, on par with the best known techniques power of such a device can approach the order of using standard superlattice structures. The structure proposed here helps pave the way toward designing graphene electronics which use geometry rather than gating to control devices.
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In this paper, operator-based nonlinear water temperature control for a group of three connected microreactors actuated by Peltier devices is proposed. To control the water temperature of tube in the microreactor, the temperature change of aluminum effects is considered. Therefore, the temperature change of aluminum becomes the part of an input of the tube. First, nonlinear thermal models of aluminum plates and tubes that structure the microreactor are obtained. Then, an operator based nonlinear water temperature control system for the microreactor is designed. Finally, the effectiveness of the proposed models and methods is confirmed by simulation and experimental results.
