To assist emergency management planning and prevention in case of hazardous chemical release into the atmosphere,especially in densely built-up regions with large populations,a multi-scale urban atmospheric dispersion...To assist emergency management planning and prevention in case of hazardous chemical release into the atmosphere,especially in densely built-up regions with large populations,a multi-scale urban atmospheric dispersion model was established.Three numerical dispersion experiments,at horizontal resolutions of 10 m,50 m and 3000 m,were performed to estimate the adverse effects of toxic chemical release in densely built-up areas.The multi-scale atmospheric dispersion model is composed of the Weather Forecasting and Research （WRF） model,the Open Source Field Operation and Manipulation software package,and a Lagrangian dispersion model.Quantification of the adverse health effects of these chemical release events are given by referring to the U.S.Environmental Protection Agency＇s Acute Exposure Guideline Levels.The wind fields of the urban-scale case,with 3 km horizontal resolution,were simulated by the Beijing Rapid Update Cycle system,which were utilized by the WRF model.The sub-domain-scale cases took advantage of the computational fluid dynamics method to explicitly consider the effects of buildings.It was found that the multi-scale atmospheric dispersion model is capable of simulating the flow pattern and concentration distribution on different scales,ranging from several meters to kilometers,and can therefore be used to improve the planning of prevention and response programs.展开更多
Taking the revitalization strategy in conservation and renewal of Shangxiahang historical and cultural district as an example,the paper analyzes the main problems at the present stage and the main contradictions with ...Taking the revitalization strategy in conservation and renewal of Shangxiahang historical and cultural district as an example,the paper analyzes the main problems at the present stage and the main contradictions with urban development,and puts forward the revitalization practice for conservation and renewal of Shangxiahang historical district by using related revitalization theory and planning principles.Furthermore,the contemporary practicality of Shangxiahang district is increased on the basis of protection,giving play to its contemporary charm.展开更多
Dielectric elastomer actuators(DEAs) have attracted much interest over the past decades due to the inherent flexibility, large strain, high efficiency, high energy density, and fast response of the material, which are...Dielectric elastomer actuators(DEAs) have attracted much interest over the past decades due to the inherent flexibility, large strain, high efficiency, high energy density, and fast response of the material, which are known as one of the most promising candidates for artificial muscle. In this paper, we first introduce the actuation principle and electromechanical modeling approaches of dielectric elastomers(DEs). Then, the performance of different DEs material and existing compliant electrodes that are widely utilized for DEAs are presented. We also highlight the compatibility of DEs, which is suitable for a variety of actuator designs and applications. Lastly, we summarize the challenges and future development in terms of electromechanical modeling, improvement of materials including compliant electrodes and dielectric elastomer, designs and applications of novel dielectric elastomer actuators.展开更多
基金supported by the Public Welfare Special Fund Program (Meteorology) of the Chinese Ministry of Finance (Grant No.GYHY201106033)
文摘To assist emergency management planning and prevention in case of hazardous chemical release into the atmosphere,especially in densely built-up regions with large populations,a multi-scale urban atmospheric dispersion model was established.Three numerical dispersion experiments,at horizontal resolutions of 10 m,50 m and 3000 m,were performed to estimate the adverse effects of toxic chemical release in densely built-up areas.The multi-scale atmospheric dispersion model is composed of the Weather Forecasting and Research （WRF） model,the Open Source Field Operation and Manipulation software package,and a Lagrangian dispersion model.Quantification of the adverse health effects of these chemical release events are given by referring to the U.S.Environmental Protection Agency＇s Acute Exposure Guideline Levels.The wind fields of the urban-scale case,with 3 km horizontal resolution,were simulated by the Beijing Rapid Update Cycle system,which were utilized by the WRF model.The sub-domain-scale cases took advantage of the computational fluid dynamics method to explicitly consider the effects of buildings.It was found that the multi-scale atmospheric dispersion model is capable of simulating the flow pattern and concentration distribution on different scales,ranging from several meters to kilometers,and can therefore be used to improve the planning of prevention and response programs.
文摘Taking the revitalization strategy in conservation and renewal of Shangxiahang historical and cultural district as an example,the paper analyzes the main problems at the present stage and the main contradictions with urban development,and puts forward the revitalization practice for conservation and renewal of Shangxiahang historical district by using related revitalization theory and planning principles.Furthermore,the contemporary practicality of Shangxiahang district is increased on the basis of protection,giving play to its contemporary charm.
基金supported by the National Natural Science Foundation of China(Grant Nos.51575187&91223201)Science and Technology Program of Guangzhou(Grant No.2014Y2-00217)+3 种基金Science and Technology Major Project of Huangpu District of Guangzhou(Grant No.20150000661)Research Project of State Key Laboratory of Mechanical System and Vibration(Grant No.MSV201405)the Fundamental Research Funds for the Central University(Grant No.2015ZZ007)the Natural Science Foundation of Guangdong Province(Grant No.S2013030013355)
文摘Dielectric elastomer actuators(DEAs) have attracted much interest over the past decades due to the inherent flexibility, large strain, high efficiency, high energy density, and fast response of the material, which are known as one of the most promising candidates for artificial muscle. In this paper, we first introduce the actuation principle and electromechanical modeling approaches of dielectric elastomers(DEs). Then, the performance of different DEs material and existing compliant electrodes that are widely utilized for DEAs are presented. We also highlight the compatibility of DEs, which is suitable for a variety of actuator designs and applications. Lastly, we summarize the challenges and future development in terms of electromechanical modeling, improvement of materials including compliant electrodes and dielectric elastomer, designs and applications of novel dielectric elastomer actuators.
