A numerical model of thermoelectric module (TEM) is created by academic analysis,and the impacts of the resistance ratio and thermoelement size on the output power and thermoelectric efficiency of the TEM are analyz...A numerical model of thermoelectric module (TEM) is created by academic analysis,and the impacts of the resistance ratio and thermoelement size on the output power and thermoelectric efficiency of the TEM are analyzed by the MATLAB numerical calculation.The numerical model is validated by the ANSYS thermal,electrical,and structural coupling simulation.The effects of the variable physical property parameters and contact effect on the output power and thermoelectric efficiency are evaluated,and the concept of aspect ratio optimal domain is proposed,which provides a new design approach for the TEM.展开更多
The present paper reviewed the researches of how they have affected agricultural pests in the territory of Mexico. It emphasizes that traditional climate models are not “predict” non-linear systems and are necessary...The present paper reviewed the researches of how they have affected agricultural pests in the territory of Mexico. It emphasizes that traditional climate models are not “predict” non-linear systems and are necessary to resort to the construction of scenarios for study. Some climate change models applied to Mexico used for this purpose obtained significant results. It showed that to better understand the ecology of pests and their hosts, it is necessary to further research the correlations between them and improve climate modeling and its consequences, to prioritize risks and improve the reliability of predictions and scenarios in the future.展开更多
This article presented a four-fingered soft bionic robotic gripper with variable effective actuator lengths. By combining approaches of finite element analysis, quasi-static analytical modeling, and experimental measu...This article presented a four-fingered soft bionic robotic gripper with variable effective actuator lengths. By combining approaches of finite element analysis, quasi-static analytical modeling, and experimental measurements, the deformation of the single soft actuator as a function of air pressure input in free space was analyzed. To investigate the effect of the effective actuator length on the gripping per- formance of the gripper, we conducted systematical experiments to evaluate the pull-off force, the actuation speed, the precision and error tolerance of the soft gripper while grasping objects of various sizes and shapes. A combination of depressurization and pressurization in actuation as well as applying variable effective actuator length enhanced the gripper's performance significantly, with no sensors. For example, with tunable effective actuator length, the gripper was able to grasp objects ranging from 2 mm 170 mm robustly. Under the optimal length, the gripper could generate the maximum pull-off force for the corresponding object size; the precision and the error tolerance of the gripper were also significantly improved compared to those of the gripper with full-length. Our soft robotic prototype exhibits a simple control and low-cost approach of gripping a wide range of objects and may have wide leverage for future industrial operations.展开更多
Indoor air dynamics and quality in high density residential buildings can be complex as it is affected by both building parameters,pollution sources,and outdoor meteorological conditions.The present study used CONTAM ...Indoor air dynamics and quality in high density residential buildings can be complex as it is affected by both building parameters,pollution sources,and outdoor meteorological conditions.The present study used CONTAM simulations to investigate the intra-building transport and concentration of an inert pollutant continuously emitted from an underground garage of a 15-floor building under moderate Mediterranean weather.The effects of outdoor meteorological conditions(air temperature,wind speed and direction)on indoor distribution of the emitted pollutant was tested under constant conditions.The importance of using actual transient meteorological data and the impact of their temporal resolution on calculated concentrations and exposure levels were also investigated.Vertical profiles of air exchange rate(AER)and CO concentration were shown to be sensitive to indoor-outdoor temperature difference,which controls the extent of the stack effect and its importance relative to wind effect.Even under constant conditions,transient mode simulations revealed that the time needed for pollutant distribution to reach steady state can be quite long(>24h in some cases).The temporal resolution(Ih vs.8h)of the meteorological data input was also found to impact calculated exposure levels,in an extent that varied with time,meteorological conditions and apartment position.展开更多
This paper investigates the impact of China's outward foreign direct investment (OFDI) on its economic growth. By using a provincial-level panel dataset and applying fixed- effects and instrumental variable regress...This paper investigates the impact of China's outward foreign direct investment (OFDI) on its economic growth. By using a provincial-level panel dataset and applying fixed- effects and instrumental variable regression techniques, the study finds that both OFDI from provincial firms and OFDI from state-owned enterprises have a positive impact on China's provincial economic growth. The positive impact of OFDI on provincial economic growth may be the result of reverse knowledge spillovers from OFDI to the home provincial economy through demonstration and imitation, labor movement, and backward and forward industrial linkages, thus increasing the productivity and the efficiency of home firms and promoting the growth of the home economy.展开更多
基金Funded by Guangdong Natural Science Foundation (No.00355991220615019)
文摘A numerical model of thermoelectric module (TEM) is created by academic analysis,and the impacts of the resistance ratio and thermoelement size on the output power and thermoelectric efficiency of the TEM are analyzed by the MATLAB numerical calculation.The numerical model is validated by the ANSYS thermal,electrical,and structural coupling simulation.The effects of the variable physical property parameters and contact effect on the output power and thermoelectric efficiency are evaluated,and the concept of aspect ratio optimal domain is proposed,which provides a new design approach for the TEM.
文摘The present paper reviewed the researches of how they have affected agricultural pests in the territory of Mexico. It emphasizes that traditional climate models are not “predict” non-linear systems and are necessary to resort to the construction of scenarios for study. Some climate change models applied to Mexico used for this purpose obtained significant results. It showed that to better understand the ecology of pests and their hosts, it is necessary to further research the correlations between them and improve climate modeling and its consequences, to prioritize risks and improve the reliability of predictions and scenarios in the future.
基金Acknowledgment This work was supported by the National Science Foundation support projects, China (grant numbers 61633004, 61403012, and 61333016) the Open Research Fund of Key Laboratory Space Utilization, Chinese Academy of Sciences (No.6050000201607004). Many thanks to Ziyu Ren and Hui Wang for their kind help in implementing the experimental apparatus, con- ducting the force experiments and performing the data analysis. Thanks to Xi Fang for her kind help in revising the paper.
文摘This article presented a four-fingered soft bionic robotic gripper with variable effective actuator lengths. By combining approaches of finite element analysis, quasi-static analytical modeling, and experimental measurements, the deformation of the single soft actuator as a function of air pressure input in free space was analyzed. To investigate the effect of the effective actuator length on the gripping per- formance of the gripper, we conducted systematical experiments to evaluate the pull-off force, the actuation speed, the precision and error tolerance of the soft gripper while grasping objects of various sizes and shapes. A combination of depressurization and pressurization in actuation as well as applying variable effective actuator length enhanced the gripper's performance significantly, with no sensors. For example, with tunable effective actuator length, the gripper was able to grasp objects ranging from 2 mm 170 mm robustly. Under the optimal length, the gripper could generate the maximum pull-off force for the corresponding object size; the precision and the error tolerance of the gripper were also significantly improved compared to those of the gripper with full-length. Our soft robotic prototype exhibits a simple control and low-cost approach of gripping a wide range of objects and may have wide leverage for future industrial operations.
文摘Indoor air dynamics and quality in high density residential buildings can be complex as it is affected by both building parameters,pollution sources,and outdoor meteorological conditions.The present study used CONTAM simulations to investigate the intra-building transport and concentration of an inert pollutant continuously emitted from an underground garage of a 15-floor building under moderate Mediterranean weather.The effects of outdoor meteorological conditions(air temperature,wind speed and direction)on indoor distribution of the emitted pollutant was tested under constant conditions.The importance of using actual transient meteorological data and the impact of their temporal resolution on calculated concentrations and exposure levels were also investigated.Vertical profiles of air exchange rate(AER)and CO concentration were shown to be sensitive to indoor-outdoor temperature difference,which controls the extent of the stack effect and its importance relative to wind effect.Even under constant conditions,transient mode simulations revealed that the time needed for pollutant distribution to reach steady state can be quite long(>24h in some cases).The temporal resolution(Ih vs.8h)of the meteorological data input was also found to impact calculated exposure levels,in an extent that varied with time,meteorological conditions and apartment position.
文摘This paper investigates the impact of China's outward foreign direct investment (OFDI) on its economic growth. By using a provincial-level panel dataset and applying fixed- effects and instrumental variable regression techniques, the study finds that both OFDI from provincial firms and OFDI from state-owned enterprises have a positive impact on China's provincial economic growth. The positive impact of OFDI on provincial economic growth may be the result of reverse knowledge spillovers from OFDI to the home provincial economy through demonstration and imitation, labor movement, and backward and forward industrial linkages, thus increasing the productivity and the efficiency of home firms and promoting the growth of the home economy.