The innovation of technologzv and the improvement of people＇s living standard accelerate the replacement of consumer electronic appliances, resulting in a significant increase of waste household electronic appliances...The innovation of technologzv and the improvement of people＇s living standard accelerate the replacement of consumer electronic appliances, resulting in a significant increase of waste household electronic appliances （WHEA）. To address the environmental problems of WHEA, many countries have enacted legislation according to WHEA management, including collecting, processing and recycling. The regulations on the management of WHEA were also drafted in China and pilot programs of WHEA recycling management encountered difficulties in collecting WHEA. The success of a recycling scheme is dependent on people＇s willingness of participating in the scheme, This paper applies Ajzen＇s theory of planned behavior to seek the main factors to engourage consumers to participate in WHEA recycling management in China. Data from a survey conducted with a sample of 633 consumers show that service motivation is the first predictor of participation behavior intention, followed by environmental behavior attitude, economic motivation, subjective norm. and perceived behavior barrier. Environmental knowledge is found not to be the predictor of behavior intention in this recycling scheme. Study results also suggest that publicity is the key situational factor in the WHEA recycling management. Recycling network and policy have little influence on changing consumers＇ current behavior intention and participation. Implications of the findings are discussed and future research directions are suggested in the end.展开更多
Since 1865, the scholars from different countries have been studying the Genoese Massari＇s ledger of 1340. The authors have used a fundamentally new approach when studying this famous register. The authors have also ...Since 1865, the scholars from different countries have been studying the Genoese Massari＇s ledger of 1340. The authors have used a fundamentally new approach when studying this famous register. The authors have also analyzed the full-scale financial processes （from registering the expenses of the commune to their coverage by revenue） instead of analyzing some separate transactions which could prove the presence of the double-entry when registering each economic fact. This becomes possible as a result of the reconstruction of medieval entries and registers in the form of a modem account and the construction of the computer model of the whole ledger of 1340. The model of the system is formed according to seven summits of the revenue of the commune, which are distributed upon many factors of registered expenses and united into 17 reporting points. The special attention is paid to the date of the transaction. The authors have found many answers to some questions which were mysteries before. The explanation is given to the sales of goods below the purchasing price and to the exchange of money with significant losses.展开更多
The wireless electric vehicle(EV) charging system is highly safe and flexible. To reduce the weight and cost of EVs, the wireless charging system, which simplifies the structure inside an EV and utilizes the transmitt...The wireless electric vehicle(EV) charging system is highly safe and flexible. To reduce the weight and cost of EVs, the wireless charging system, which simplifies the structure inside an EV and utilizes the transmitter-side control method, has become popular. This study investigates the transmitter-side control methods in a wireless EV charging system. First, a universal wireless charging system is introduced, and the function of its transfer power is derived. It is observed that the transfer power can be controlled by regulating either the phase-shift angle or the DC-link voltage. Further, the influence of the control variables is studied using numerical analysis. Additionally, the corresponding control methods, namely the phase-shift angle and the DC-link voltage control, are compared by calculation and simulation. It is found that:(1) the system efficiency is low with the phase-shift control method because of the converter switching loss;(2) the dynamic response is slow with the DC-link voltage control method because of the large inertia of the inductor and capacitor;(3) both the control methods have limitations in their adjustable power range. Therefore, a combined control method is proposed, with the advantages of high system efficiency, fast dynamic response, and wide adjustable power range. Finally, experiments are performed to verify the validity of the theoretical analysis and the effectiveness of the proposed method. This study provides a detailed and comprehensive analysis of the transmitter-side control methods in the wireless charging system, considering the sensitivity of parameters, converter losses, system efficiency,and dynamic performance, with the dead-time effect taken into consideration. Moreover, the proposed control method can be used to realize the optimal combination of the phase-shift angle and the DC-link voltage with good dynamic performance, and it is useful for the optimal operation of the wireless charging system.展开更多
The charging kinetics of electric double layers （EDLs） is closely related to the performance of a wide variety of nanostructured devices including supercapacitors, electro-actuators, and electrolyte-gated transistor...The charging kinetics of electric double layers （EDLs） is closely related to the performance of a wide variety of nanostructured devices including supercapacitors, electro-actuators, and electrolyte-gated transistors. While room temperature ionic liquids （RTIL） are often used as the charge carrier in these new applications, the theoretical analyses are mostly based on conventional electrokinetic theories suitable for macroscopic electrochemical phenomena in aqueous solutions. In this work, we study the charging behavior of RTIL-EDLs using a coarse-grained molecular model and constant-potential molecular dynamics （MD） simulations. In stark contrast to the predictions of conventional theories, the MD results show oscillatory variations of ionic distributions and electrochemical properties in response to the separation between electrodes. The rate of EDL charging exhibits non-monotonic behavior revealing strong electrostatic correlations in RTIL under confinement.展开更多
文摘The innovation of technologzv and the improvement of people＇s living standard accelerate the replacement of consumer electronic appliances, resulting in a significant increase of waste household electronic appliances （WHEA）. To address the environmental problems of WHEA, many countries have enacted legislation according to WHEA management, including collecting, processing and recycling. The regulations on the management of WHEA were also drafted in China and pilot programs of WHEA recycling management encountered difficulties in collecting WHEA. The success of a recycling scheme is dependent on people＇s willingness of participating in the scheme, This paper applies Ajzen＇s theory of planned behavior to seek the main factors to engourage consumers to participate in WHEA recycling management in China. Data from a survey conducted with a sample of 633 consumers show that service motivation is the first predictor of participation behavior intention, followed by environmental behavior attitude, economic motivation, subjective norm. and perceived behavior barrier. Environmental knowledge is found not to be the predictor of behavior intention in this recycling scheme. Study results also suggest that publicity is the key situational factor in the WHEA recycling management. Recycling network and policy have little influence on changing consumers＇ current behavior intention and participation. Implications of the findings are discussed and future research directions are suggested in the end.
文摘Since 1865, the scholars from different countries have been studying the Genoese Massari＇s ledger of 1340. The authors have used a fundamentally new approach when studying this famous register. The authors have also analyzed the full-scale financial processes （from registering the expenses of the commune to their coverage by revenue） instead of analyzing some separate transactions which could prove the presence of the double-entry when registering each economic fact. This becomes possible as a result of the reconstruction of medieval entries and registers in the form of a modem account and the construction of the computer model of the whole ledger of 1340. The model of the system is formed according to seven summits of the revenue of the commune, which are distributed upon many factors of registered expenses and united into 17 reporting points. The special attention is paid to the date of the transaction. The authors have found many answers to some questions which were mysteries before. The explanation is given to the sales of goods below the purchasing price and to the exchange of money with significant losses.
基金supported by the International Science and Technology Cooperation Program of China(Grant No.2016YFE0102200)
文摘The wireless electric vehicle(EV) charging system is highly safe and flexible. To reduce the weight and cost of EVs, the wireless charging system, which simplifies the structure inside an EV and utilizes the transmitter-side control method, has become popular. This study investigates the transmitter-side control methods in a wireless EV charging system. First, a universal wireless charging system is introduced, and the function of its transfer power is derived. It is observed that the transfer power can be controlled by regulating either the phase-shift angle or the DC-link voltage. Further, the influence of the control variables is studied using numerical analysis. Additionally, the corresponding control methods, namely the phase-shift angle and the DC-link voltage control, are compared by calculation and simulation. It is found that:(1) the system efficiency is low with the phase-shift control method because of the converter switching loss;(2) the dynamic response is slow with the DC-link voltage control method because of the large inertia of the inductor and capacitor;(3) both the control methods have limitations in their adjustable power range. Therefore, a combined control method is proposed, with the advantages of high system efficiency, fast dynamic response, and wide adjustable power range. Finally, experiments are performed to verify the validity of the theoretical analysis and the effectiveness of the proposed method. This study provides a detailed and comprehensive analysis of the transmitter-side control methods in the wireless charging system, considering the sensitivity of parameters, converter losses, system efficiency,and dynamic performance, with the dead-time effect taken into consideration. Moreover, the proposed control method can be used to realize the optimal combination of the phase-shift angle and the DC-link voltage with good dynamic performance, and it is useful for the optimal operation of the wireless charging system.
基金This work was supported as part of the Fluid Interface Reactions, Structures and Transport （FIRST） Center, an Energy Frontier Research Center funded by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences. K. X. is grateful to the Chinese Scholarship Council for a visiting fellowship. Additional support was provided by National Natural Science foundation of China （No. 21276138） and Tsinghua University Foundation （No. 2013108930）. The numerical calculations were performed at the National Energy Research Sdentific Computing Center （NERSC）.
文摘The charging kinetics of electric double layers （EDLs） is closely related to the performance of a wide variety of nanostructured devices including supercapacitors, electro-actuators, and electrolyte-gated transistors. While room temperature ionic liquids （RTIL） are often used as the charge carrier in these new applications, the theoretical analyses are mostly based on conventional electrokinetic theories suitable for macroscopic electrochemical phenomena in aqueous solutions. In this work, we study the charging behavior of RTIL-EDLs using a coarse-grained molecular model and constant-potential molecular dynamics （MD） simulations. In stark contrast to the predictions of conventional theories, the MD results show oscillatory variations of ionic distributions and electrochemical properties in response to the separation between electrodes. The rate of EDL charging exhibits non-monotonic behavior revealing strong electrostatic correlations in RTIL under confinement.
