Electrochemical extraction of contaminants from soils is a promising soil decontamination technology. Various experiments have been conducted to study electrochemical reactions and geochemical processes in the electro...Electrochemical extraction of contaminants from soils is a promising soil decontamination technology. Various experiments have been conducted to study electrochemical reactions and geochemical processes in the electrochemical extraction using different experimental apparatuses. This paper presents the development of a new closed two-dimensional(2D) apparatus that can better simulate the field application of the technology and accurately monitor the most important electrochemical parameters to understand the process. The innovative features of the new apparatus include the outer and inner electrodes designed to apply a non-uniform electrical field across the specimen as in the field electrochemical remediation process, the probes installed to measure the 2D distribution of electrical voltage, and the gas and fluid volume measurement devices used to accurately monitor the gas generation and electroosmotic flow rates at both electrodes as a function of time. The components of this new apparatus and the features of each component are described. The operating procedure and some typical results from three experiments with the apparatus are demonstrated. The results show that the variation of the gas generation rate is in good agreement with the electric current. Their relation provides a valid evaluation for electrochemical behavior of the system and Faraday's laws of electrolysis. The 2D profiles of cadmium concentration and voltage distribution at the end of the experiment reveal the great effects of a non-uniform electrical field on the contaminant mobilization.展开更多
We report a theoretic study on the inverse spin-Hall effect （ISHE） in a two-terminal nano-device that consists of a two-dimensional electron gas （2DEG） with Rashba spin-orbit coupling （RSOC） and two ideal leads....We report a theoretic study on the inverse spin-Hall effect （ISHE） in a two-terminal nano-device that consists of a two-dimensional electron gas （2DEG） with Rashba spin-orbit coupling （RSOC） and two ideal leads. Based on a two-site toy model and Keldysh Green＇s function method, we derive an analytic result of ISHE, which shows clearly that a nonzero transverse charge current stems from the combined effect of the RSOC, the spin bias, and its spin polarization direction in spin space. Our further numerical calculations in a larger system other than two-site lattice model demonstrate that the transverse charge current, dependent on the strength of the RSOC, the Fermi energy of the system, as well as the system size, can exhibit oscillating behavior and even reverse its sign due to Rashba spin precession. These properties may be helpful for eficient detection of the spin current （spin bias） by measuring the transverse charge current in a spin-orbital coupling system.展开更多
In this study,a jet cavitation device aimed at producing two-dimensional nanosheets was designed.The effects of cavitation generator type and jet pressure on the cavitation inception and intensity were examined by mon...In this study,a jet cavitation device aimed at producing two-dimensional nanosheets was designed.The effects of cavitation generator type and jet pressure on the cavitation inception and intensity were examined by monitoring the changes of sound pressure level(SPL).As such,the optimized cavitation generator with the best cavitation capability under the same ambient condition was determined.Further,BN and MoS 2,two kinds of layered materials,were exfoliated into individual flakes in aqueous solutions by this jet cavitation device.By investigating the morphology of these exfoliated flakes via scanning electron microscopy and transmission electron microscope,it was found that these pristine materials were mostly exfoliated into two-dimensional nanosheets,among which even monolayers were generally presented.This exfoliation process happened mainly due to the cavitation-induced intensive tensile stress acting on the layered materials.As graphene has been produced by this device successfully,it is anticipated that this jet cavitation device is suitable for producing other various two-dimensional nanosheets.展开更多
A grate cooler is key equipment in quenching clinker and recovering heat in cement production. A two-dimensional numerical model based on a 5000 t/d cement plant is proposed to for a study on the gas-solid coupled hea...A grate cooler is key equipment in quenching clinker and recovering heat in cement production. A two-dimensional numerical model based on a 5000 t/d cement plant is proposed to for a study on the gas-solid coupled heat transfer process between the cooling air and clinker in a grate cooler. In this study, we use the Fluent dynamic mesh technique and porous media model through which the transient temperature distribution with the clinker motion process and steady temperature and pressure distribution are obtained. We validate the numerical model with the operating data of the cooling air outlet temperature. Then, we discuss the amount of mid-temperature air outlet and average diameter of clinker particles, which affect the heat effective utilization and cooling air pressure drop in clinker layer. We found that after adding one more mid-temperature air outlet, the average temperature of the air flowing into the heat recovery boiler increases by 29.04℃ and the ratio of heat effective utilization increases by 5.3%. This means heat recovery is more effective on adding one more mid-temperature air outlet. Further, the smaller the clinker particles, the more is the pressure drop in clinker layer; thus more power consumption is needed by the cooling fan.展开更多
基金Supported by the National Natural Science Foundation of China(41201303,20807028,41372262)the Fundamental Research for the Central Universities(14CX02052A,14CX02191A)+1 种基金the Qingdao Science and Technology Program for young scientists(14-2-4-86-jch)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(PCRRF13023)
文摘Electrochemical extraction of contaminants from soils is a promising soil decontamination technology. Various experiments have been conducted to study electrochemical reactions and geochemical processes in the electrochemical extraction using different experimental apparatuses. This paper presents the development of a new closed two-dimensional(2D) apparatus that can better simulate the field application of the technology and accurately monitor the most important electrochemical parameters to understand the process. The innovative features of the new apparatus include the outer and inner electrodes designed to apply a non-uniform electrical field across the specimen as in the field electrochemical remediation process, the probes installed to measure the 2D distribution of electrical voltage, and the gas and fluid volume measurement devices used to accurately monitor the gas generation and electroosmotic flow rates at both electrodes as a function of time. The components of this new apparatus and the features of each component are described. The operating procedure and some typical results from three experiments with the apparatus are demonstrated. The results show that the variation of the gas generation rate is in good agreement with the electric current. Their relation provides a valid evaluation for electrochemical behavior of the system and Faraday's laws of electrolysis. The 2D profiles of cadmium concentration and voltage distribution at the end of the experiment reveal the great effects of a non-uniform electrical field on the contaminant mobilization.
基金Supported by National Natural Science Foundation of China under Grant No.10704016National Natural Science Foundation of Jiangsu Province under Grant No.BK2007100New Teacher Fund of Ministry of Education of China under Grant No.20070286036
文摘We report a theoretic study on the inverse spin-Hall effect （ISHE） in a two-terminal nano-device that consists of a two-dimensional electron gas （2DEG） with Rashba spin-orbit coupling （RSOC） and two ideal leads. Based on a two-site toy model and Keldysh Green＇s function method, we derive an analytic result of ISHE, which shows clearly that a nonzero transverse charge current stems from the combined effect of the RSOC, the spin bias, and its spin polarization direction in spin space. Our further numerical calculations in a larger system other than two-site lattice model demonstrate that the transverse charge current, dependent on the strength of the RSOC, the Fermi energy of the system, as well as the system size, can exhibit oscillating behavior and even reverse its sign due to Rashba spin precession. These properties may be helpful for eficient detection of the spin current （spin bias） by measuring the transverse charge current in a spin-orbital coupling system.
基金supported by the Special Financial Support of Joint Building Project of the Beijing Education Committee
文摘In this study,a jet cavitation device aimed at producing two-dimensional nanosheets was designed.The effects of cavitation generator type and jet pressure on the cavitation inception and intensity were examined by monitoring the changes of sound pressure level(SPL).As such,the optimized cavitation generator with the best cavitation capability under the same ambient condition was determined.Further,BN and MoS 2,two kinds of layered materials,were exfoliated into individual flakes in aqueous solutions by this jet cavitation device.By investigating the morphology of these exfoliated flakes via scanning electron microscopy and transmission electron microscope,it was found that these pristine materials were mostly exfoliated into two-dimensional nanosheets,among which even monolayers were generally presented.This exfoliation process happened mainly due to the cavitation-induced intensive tensile stress acting on the layered materials.As graphene has been produced by this device successfully,it is anticipated that this jet cavitation device is suitable for producing other various two-dimensional nanosheets.
基金supported by the Horizontal Subject(Grant No.11471501)the National Basic Research Program of China("973"Project)(Grant No.2013CB228305)
文摘A grate cooler is key equipment in quenching clinker and recovering heat in cement production. A two-dimensional numerical model based on a 5000 t/d cement plant is proposed to for a study on the gas-solid coupled heat transfer process between the cooling air and clinker in a grate cooler. In this study, we use the Fluent dynamic mesh technique and porous media model through which the transient temperature distribution with the clinker motion process and steady temperature and pressure distribution are obtained. We validate the numerical model with the operating data of the cooling air outlet temperature. Then, we discuss the amount of mid-temperature air outlet and average diameter of clinker particles, which affect the heat effective utilization and cooling air pressure drop in clinker layer. We found that after adding one more mid-temperature air outlet, the average temperature of the air flowing into the heat recovery boiler increases by 29.04℃ and the ratio of heat effective utilization increases by 5.3%. This means heat recovery is more effective on adding one more mid-temperature air outlet. Further, the smaller the clinker particles, the more is the pressure drop in clinker layer; thus more power consumption is needed by the cooling fan.
