Due to the serious greenhouse gas effects caused by the increasing concentration of atmospheric CO_2,carbon capture and storage(CCS) has been an important area of research and many technologies are developed within th...Due to the serious greenhouse gas effects caused by the increasing concentration of atmospheric CO_2,carbon capture and storage(CCS) has been an important area of research and many technologies are developed within this field. Molten salt CO_2 capture and electrochemical transformation(MSCC-ET) process is a desirable method due to a high CO_2 solubility, a wide potential window of molten salts and easily-controlled electrode reactions. Generally, electro-splitting CO_2 in molten salts begins with CO_2 absorption reactions to form CO_3^(2-), which is then followed by the carbon deposition at the cathode and O_2 evolution at the anode. As a result, CO_2 is electro-converted to O_2 and carbon with different morphologies, compositions, microstructures and functional properties. This report introduces the MSCC-ET process, summarizes the reactions occurring in the molten salts and at the electrode surfaces, as well as the morphological variations of the cathodic products. The inert anode materials, cost estimation and scale-up evaluation of the process are then discussed. It is presumed that with a comprehensive understanding of the electrode reactions during electrolysis and the functional properties of carbon materials obtained during CO_2 electro-splitting can provide a foundation for further developing this environmentally friendly process.展开更多
The increased concern over global climate change and lack of long-term sustainability of fossil fuels in the projected future has prompted further research into advanced alternative fuel vehicles to reduce vehicle emi...The increased concern over global climate change and lack of long-term sustainability of fossil fuels in the projected future has prompted further research into advanced alternative fuel vehicles to reduce vehicle emissions and fuel consumption. One of the primary advanced vehicle research areas involves electrification and hybridization of vehicles. As hybrid-electric vehicle technology has advanced, so has the need for more innovative control schemes for hybrid vehicles, including the development and optimization of hybrid powertrain transmission shift schedules. The hybrid shift schedule works in tandem with a cost function-based torque split algorithm that dynamically determines the optimal torque command for the electric motor and engine. The focus of this work is to develop and analyze the benefits and limitations of two different shift schedules for a position-3 (P3) parallel hybrid-electric vehicle. a traditional two-parameter shift schedule that operates as a function of vehicle accelerator position and vehicle speed (state of charge (SOC) independent shift schedule), and a three-parameter shift schedule that also adapts to fluctuations in the state of charge of the high voltage batteries (SOC dependent shift schedule). The shift schedules were generated using an exhaustive search coupled with a fitness function to evaluate all possible vehicle operating points. The generated shift schedules were then tested in the software-in-the-loop (SIL) environment and the vehicle-in-the-loop (VIL) environment and compared to each other, as well as to the stock 8L45 8-speed transmission shift schedule. The results show that both generated shift schedules improved upon the stock transmission shift schedule used in the hybrid powertrain comparing component efficiency, vehicle efficiency, engine fuel economy, and vehicle fuel economy.展开更多
Due to the transboundary nature of air pollutants,a province's efforts to improve air quality can reduce PM_(2.5) concentration in the surrounding area.The inter-provincial PM_(2.5) pollution transport could bring...Due to the transboundary nature of air pollutants,a province's efforts to improve air quality can reduce PM_(2.5) concentration in the surrounding area.The inter-provincial PM_(2.5) pollution transport could bring great challenges to related environmental management work,such as financial fund allocation and subsidy policy formulation.Herein,we examined the transport characteristics of PM_(2.5) pollution across provinces in 2013 and 2020 via chemical transport modeling and then monetized inter-provincial contributions of PM_(2.5) improvement based on pollutant emission control costs.We found that approximately 60%of the PM_(2.5) pollution was from local sources,while the remaining 40%originated from outside provinces.Furthermore,about 1011 billion RMB of provincial air pollutant abatement costs contributed to the PM_(2.5) concentration decline in other provinces during 2013-2020,accounting for 41.2%of the total abatement costs.Provinces with lower unit improvement costs for PM_(2.5),such as Jiangsu,Hebei,and Shandong,were major contributors,while Guangdong,Guangxi,and Fujian,bearing higher unit costs,were among the main beneficiaries.Our study identifies provinces that contribute to air quality improvement in other provinces,have high economic efficiency,and provide a quantitative framework for determining inter-provincial compensations.This study also reveals the uneven distribution of pollution abatement costs(PM_(2.5) improvement/abatement costs)due to transboundary PM_(2.5) transport,calling for adopting inter-provincial economic compensation policies.Such mechanisms ensure equitable cost-sharing and effective regional air quality management.展开更多
为了减小高性能视频编码(high efficiency video coding,HEVC)的复杂度,提出一种基于四叉树结构类型分析的帧间预测模式快速决策改进算法。一方面,统计并分析空时域相邻编码单元(coding unit,CU)和CU深度之间的相关性,确定其深度遍历区...为了减小高性能视频编码(high efficiency video coding,HEVC)的复杂度,提出一种基于四叉树结构类型分析的帧间预测模式快速决策改进算法。一方面,统计并分析空时域相邻编码单元(coding unit,CU)和CU深度之间的相关性,确定其深度遍历区间,跳过一些冗余CU的分割,从而减少CU深度划分的复杂度;另一方面,通过分析遍历区间内CU的运动特征和预测单元(prediction unit,PU)模式特性,确定不同运动特征所对应的PU模式,减少所需遍历候选PU模式的数量和所需要进行的率失真代价计算的数量。与HM14.0相比,采用该算法的HEVC编码器在输出比特率增加很小的情况下,平均编码时间降低了46.9%,而编码后的视频质量基本不变。展开更多
基金funding support from the National Natural Science Foundation of China (51722404 and 51674177)
文摘Due to the serious greenhouse gas effects caused by the increasing concentration of atmospheric CO_2,carbon capture and storage(CCS) has been an important area of research and many technologies are developed within this field. Molten salt CO_2 capture and electrochemical transformation(MSCC-ET) process is a desirable method due to a high CO_2 solubility, a wide potential window of molten salts and easily-controlled electrode reactions. Generally, electro-splitting CO_2 in molten salts begins with CO_2 absorption reactions to form CO_3^(2-), which is then followed by the carbon deposition at the cathode and O_2 evolution at the anode. As a result, CO_2 is electro-converted to O_2 and carbon with different morphologies, compositions, microstructures and functional properties. This report introduces the MSCC-ET process, summarizes the reactions occurring in the molten salts and at the electrode surfaces, as well as the morphological variations of the cathodic products. The inert anode materials, cost estimation and scale-up evaluation of the process are then discussed. It is presumed that with a comprehensive understanding of the electrode reactions during electrolysis and the functional properties of carbon materials obtained during CO_2 electro-splitting can provide a foundation for further developing this environmentally friendly process.
文摘The increased concern over global climate change and lack of long-term sustainability of fossil fuels in the projected future has prompted further research into advanced alternative fuel vehicles to reduce vehicle emissions and fuel consumption. One of the primary advanced vehicle research areas involves electrification and hybridization of vehicles. As hybrid-electric vehicle technology has advanced, so has the need for more innovative control schemes for hybrid vehicles, including the development and optimization of hybrid powertrain transmission shift schedules. The hybrid shift schedule works in tandem with a cost function-based torque split algorithm that dynamically determines the optimal torque command for the electric motor and engine. The focus of this work is to develop and analyze the benefits and limitations of two different shift schedules for a position-3 (P3) parallel hybrid-electric vehicle. a traditional two-parameter shift schedule that operates as a function of vehicle accelerator position and vehicle speed (state of charge (SOC) independent shift schedule), and a three-parameter shift schedule that also adapts to fluctuations in the state of charge of the high voltage batteries (SOC dependent shift schedule). The shift schedules were generated using an exhaustive search coupled with a fitness function to evaluate all possible vehicle operating points. The generated shift schedules were then tested in the software-in-the-loop (SIL) environment and the vehicle-in-the-loop (VIL) environment and compared to each other, as well as to the stock 8L45 8-speed transmission shift schedule. The results show that both generated shift schedules improved upon the stock transmission shift schedule used in the hybrid powertrain comparing component efficiency, vehicle efficiency, engine fuel economy, and vehicle fuel economy.
基金the Australian large ARC grants No.DP0449535DP0559536 and DP0667060(澳大利亚ARC项目)+4 种基金the Key Project of National Natural Science Foundation of China under Grant No.60496327(国家自然科学基金重大项目)the National Natural Science Foundation of China under Grant No.60463003(国家自然科学基金)the Overseas-Returning High-level Talent Research Pro-gram of Human-Resource Ministry of China(人事部(2004-2005年度首批)海外高层次留学人才回国资助项目)the Innovation Project of Guangxi Graduate Education No.2006106020812M35(广西研究生教育创新计划资助项目).
基金National Natural Science Foundation of China under Grant No.72171157 and 72140005.
文摘Due to the transboundary nature of air pollutants,a province's efforts to improve air quality can reduce PM_(2.5) concentration in the surrounding area.The inter-provincial PM_(2.5) pollution transport could bring great challenges to related environmental management work,such as financial fund allocation and subsidy policy formulation.Herein,we examined the transport characteristics of PM_(2.5) pollution across provinces in 2013 and 2020 via chemical transport modeling and then monetized inter-provincial contributions of PM_(2.5) improvement based on pollutant emission control costs.We found that approximately 60%of the PM_(2.5) pollution was from local sources,while the remaining 40%originated from outside provinces.Furthermore,about 1011 billion RMB of provincial air pollutant abatement costs contributed to the PM_(2.5) concentration decline in other provinces during 2013-2020,accounting for 41.2%of the total abatement costs.Provinces with lower unit improvement costs for PM_(2.5),such as Jiangsu,Hebei,and Shandong,were major contributors,while Guangdong,Guangxi,and Fujian,bearing higher unit costs,were among the main beneficiaries.Our study identifies provinces that contribute to air quality improvement in other provinces,have high economic efficiency,and provide a quantitative framework for determining inter-provincial compensations.This study also reveals the uneven distribution of pollution abatement costs(PM_(2.5) improvement/abatement costs)due to transboundary PM_(2.5) transport,calling for adopting inter-provincial economic compensation policies.Such mechanisms ensure equitable cost-sharing and effective regional air quality management.
