In addition to the quality and quantity of farmland, the health of farmland has also become an important research direction in the field of farmland protection. In order to comprehensively evaluate the relationship an...In addition to the quality and quantity of farmland, the health of farmland has also become an important research direction in the field of farmland protection. In order to comprehensively evaluate the relationship and distribution of health and farmland production capacity, the depression area behind the Yellow River in Henan Province is taken as the research object. Using production capacity evaluation data and system health evaluation results, the health status and production capacity of farmland in the region are coupled. The results show that high productivity farmland is most distributed in areas with moderate health risks, while low productivity farmland is more distributed in areas with low health risks. Based on their coupling characteristics, the depression area behind the Yellow River can be divided into five types, and management and protection strategies can be formulated separately.展开更多
Aiming at the consumption problems caused by the high proportion of renewable energy being connected to the distribution network,it also aims to improve the power supply reliability of the power system and reduce the ...Aiming at the consumption problems caused by the high proportion of renewable energy being connected to the distribution network,it also aims to improve the power supply reliability of the power system and reduce the operating costs of the power system.This paper proposes a two-stage planning method for distributed generation and energy storage systems that considers the hierarchical partitioning of source-storage-load.Firstly,an electrical distance structural index that comprehensively considers active power output and reactive power output is proposed to divide the distributed generation voltage regulation domain and determine the access location and number of distributed power sources.Secondly,a two-stage planning is carried out based on the zoning results.In the phase 1 distribution network-zoning optimization layer,the network loss is minimized so that the node voltage in the area does not exceed the limit,and the distributed generation configuration results are initially determined;in phase 2,the partition-node optimization layer is planned with the goal of economic optimization,and the distance-based improved ant lion algorithm is used to solve the problem to obtain the optimal distributed generation and energy storage systemconfiguration.Finally,the IEEE33 node systemwas used for simulation.The results showed that the voltage quality was significantly improved after optimization,and the overall revenue increased by about 20.6%,verifying the effectiveness of the two-stage planning.展开更多
Sheet-bulk metal forming(SBMF)is a promising process for manufacturing complex sheet components with functional elements.In this study,the entire forming process for a typical thin-walled component with external geari...Sheet-bulk metal forming(SBMF)is a promising process for manufacturing complex sheet components with functional elements.In this study,the entire forming process for a typical thin-walled component with external gearing is investigated,including sheet forming and bulk forming processes.Deep drawn cups are prepared during sheet forming;subsequently,upsetting is performed on the sidewall to form external gearing.The upsetting method performed is known as upsetting with a controllable deformation zone(U-CDZ).Compared with the conventional upsetting method,a floating counter punch with a counter force is used in the U-CDZ method such that the forming mechanism is changed into the accumulation of the deformation zone instead of deformation throughout the entire sidewall.The effects of the counter force and material flow are investigated to understand the mechanism.The forming quality,i.e.,the formfilling and effective strain distribution,improved,whereas a high forming load is avoided.In addition,a punch with a lock bead is used to prevent folding at the inner corner during the experiment.展开更多
Zoning system is the basic mode of establishment of overall land use planning. In this study,the zoning mode and practice in the three rounds of overall land use planning that have been carried out in China were analy...Zoning system is the basic mode of establishment of overall land use planning. In this study,the zoning mode and practice in the three rounds of overall land use planning that have been carried out in China were analyzed and summarized firstly,and then some obvious problems existing in the implementation of the zoning mode were analyzed. Finally,countermeasures and suggestions were put forward to provide necessary reference for further development and improvement of the zoning mode and the development of overall land use planning at all levels in China.展开更多
Maintenance and rehabilitation projects of interstate facilities typically mandate lane closures. Lane closures require merging maneuvers that often result in reduced speeds and traffic bottlenecks. Work zone impacts ...Maintenance and rehabilitation projects of interstate facilities typically mandate lane closures. Lane closures require merging maneuvers that often result in reduced speeds and traffic bottlenecks. Work zone impacts on traffic operations are magnified when project durations are extended. Conventionally, work zone traffic control plans are developed to address work zone impacts. This study evaluated various merge control strategies at interstate work zones peak and off-peak traffic conditions and summarized related impacts. A comprehensive microscopic simulation model was developed in full consideration of driver/vehicle behavior at work zones. The analysis of simulation results revealed that merge control strategies, when implemented during peak and off-peak conditions, can preserve the level of service and provide favorable mobility, safety, and environmental impacts. In addition, results indicate that transportation agencies’ practice of scheduling work zone activities during the off-peak may not be the most optimum approach. Overall, the findings of this study highlight the need for evaluation of work zone scheduling practices in full consideration of agency, user, and project costs.展开更多
This paper investigates whether environmental regulation affects firm's performance including productivity,wage and employment using firm-level data in 1996-2007.The identification uses Two Control Zones(TCZ)polic...This paper investigates whether environmental regulation affects firm's performance including productivity,wage and employment using firm-level data in 1996-2007.The identification uses Two Control Zones(TCZ)policy implemented by the Chinese government in 1998,in which tougher environmental regulations were imposed in TCZ cities but not others.By difference-indifferences estimation,we find that tougher environmental regulation leads to larger increase on both total factor productivity and wage,and firms tend to employ fewer workers under pressure of environmental protection.Heterogeneous tests show that the impacts are better for nonpollution intensive firms,non-exporters and SOEs.Finally,we find that R&D input and exiting firms among industry are the driving forces for enhancing TFP and increasing wage and unemployment.展开更多
Chemical mechanical polishing (CMP) is the most effective wafer global planarization technology. The CMP polishing head is one of the most important components, and zone back pressure control technology is used to d...Chemical mechanical polishing (CMP) is the most effective wafer global planarization technology. The CMP polishing head is one of the most important components, and zone back pressure control technology is used to design a new generation of polishing head. The quality of polishing not only depends on slurry, but also depends on the precise control of polishing pressures. During the CMP polishing process, the set pressure of each chamber is usually not the same and the presence of a flexible elastic diaphragm causes coupling effects. Because of the coupling effects, the identification of multi-chambers and pressure controls becomes complicated. To solve the coupling problem, this paper presents a new method of multi-chamber decoupled control, and then system identification and control parameter tuning are carried out based on the method. Finally, experiments of multi- chambers inflated at the same time are performed. The experimental results show that the presented decoupling control method is feasible and correct.展开更多
In this paper we address the problem of pressure management in water supply system (WSS) network. The model-based predictive control (MPC) strategies have some important features to deal with WSS. By hydraulic ana...In this paper we address the problem of pressure management in water supply system (WSS) network. The model-based predictive control (MPC) strategies have some important features to deal with WSS. By hydraulic analysis of WSS, the predictive model is derived from the dynamic model and static model of WSS. Through WSS, the consumers' demands are required to be met at all times according to some operational constraints that must be satisfied. The constraints of flow through actuators, the water level of reservoirs and the consumer areas' pressure demand are determined by a specific system. In this work, we develop a constrained MPC controller that considers the zone control of the pressure outputs and incorporates steady state economic targets in the control cost function. The designed management strategies are applied to a case study and simulation results, covering different aspects, are provided. The output nodal pressure can be controlled in the desired zone by optimal scheduling the actuators of the WSS. If the variation range of reservoir's water level is broader, the rate of flow through the actuators is gentle, and vice versa.展开更多
基金Supported by Henan Provincial Natural Science Foundation Project(212300410168)Basic Research Business Fee Project of Henan Academy of Sciences(220601065).
文摘In addition to the quality and quantity of farmland, the health of farmland has also become an important research direction in the field of farmland protection. In order to comprehensively evaluate the relationship and distribution of health and farmland production capacity, the depression area behind the Yellow River in Henan Province is taken as the research object. Using production capacity evaluation data and system health evaluation results, the health status and production capacity of farmland in the region are coupled. The results show that high productivity farmland is most distributed in areas with moderate health risks, while low productivity farmland is more distributed in areas with low health risks. Based on their coupling characteristics, the depression area behind the Yellow River can be divided into five types, and management and protection strategies can be formulated separately.
基金supported by North China Electric Power Research Institute’s Self-Funded Science and Technology Project“Research on Distributed Energy Storage Optimal Configuration and Operation Control Technology for Photovoltaic Promotion in the Entire County”(KJZ2022049).
文摘Aiming at the consumption problems caused by the high proportion of renewable energy being connected to the distribution network,it also aims to improve the power supply reliability of the power system and reduce the operating costs of the power system.This paper proposes a two-stage planning method for distributed generation and energy storage systems that considers the hierarchical partitioning of source-storage-load.Firstly,an electrical distance structural index that comprehensively considers active power output and reactive power output is proposed to divide the distributed generation voltage regulation domain and determine the access location and number of distributed power sources.Secondly,a two-stage planning is carried out based on the zoning results.In the phase 1 distribution network-zoning optimization layer,the network loss is minimized so that the node voltage in the area does not exceed the limit,and the distributed generation configuration results are initially determined;in phase 2,the partition-node optimization layer is planned with the goal of economic optimization,and the distance-based improved ant lion algorithm is used to solve the problem to obtain the optimal distributed generation and energy storage systemconfiguration.Finally,the IEEE33 node systemwas used for simulation.The results showed that the voltage quality was significantly improved after optimization,and the overall revenue increased by about 20.6%,verifying the effectiveness of the two-stage planning.
基金Supported by National Natural Science Foundation of China(Grant Nos.51875351,51475296).
文摘Sheet-bulk metal forming(SBMF)is a promising process for manufacturing complex sheet components with functional elements.In this study,the entire forming process for a typical thin-walled component with external gearing is investigated,including sheet forming and bulk forming processes.Deep drawn cups are prepared during sheet forming;subsequently,upsetting is performed on the sidewall to form external gearing.The upsetting method performed is known as upsetting with a controllable deformation zone(U-CDZ).Compared with the conventional upsetting method,a floating counter punch with a counter force is used in the U-CDZ method such that the forming mechanism is changed into the accumulation of the deformation zone instead of deformation throughout the entire sidewall.The effects of the counter force and material flow are investigated to understand the mechanism.The forming quality,i.e.,the formfilling and effective strain distribution,improved,whereas a high forming load is avoided.In addition,a punch with a lock bead is used to prevent folding at the inner corner during the experiment.
文摘Zoning system is the basic mode of establishment of overall land use planning. In this study,the zoning mode and practice in the three rounds of overall land use planning that have been carried out in China were analyzed and summarized firstly,and then some obvious problems existing in the implementation of the zoning mode were analyzed. Finally,countermeasures and suggestions were put forward to provide necessary reference for further development and improvement of the zoning mode and the development of overall land use planning at all levels in China.
文摘Maintenance and rehabilitation projects of interstate facilities typically mandate lane closures. Lane closures require merging maneuvers that often result in reduced speeds and traffic bottlenecks. Work zone impacts on traffic operations are magnified when project durations are extended. Conventionally, work zone traffic control plans are developed to address work zone impacts. This study evaluated various merge control strategies at interstate work zones peak and off-peak traffic conditions and summarized related impacts. A comprehensive microscopic simulation model was developed in full consideration of driver/vehicle behavior at work zones. The analysis of simulation results revealed that merge control strategies, when implemented during peak and off-peak conditions, can preserve the level of service and provide favorable mobility, safety, and environmental impacts. In addition, results indicate that transportation agencies’ practice of scheduling work zone activities during the off-peak may not be the most optimum approach. Overall, the findings of this study highlight the need for evaluation of work zone scheduling practices in full consideration of agency, user, and project costs.
基金The authors are supported financially by the National Natural Science Foundation of China[Grant Number.71403216,71703128,71832012]MOE(Ministry of Education of China)of Humanities and Social Sciences Project[Grant Number.19YJC790062].
文摘This paper investigates whether environmental regulation affects firm's performance including productivity,wage and employment using firm-level data in 1996-2007.The identification uses Two Control Zones(TCZ)policy implemented by the Chinese government in 1998,in which tougher environmental regulations were imposed in TCZ cities but not others.By difference-indifferences estimation,we find that tougher environmental regulation leads to larger increase on both total factor productivity and wage,and firms tend to employ fewer workers under pressure of environmental protection.Heterogeneous tests show that the impacts are better for nonpollution intensive firms,non-exporters and SOEs.Finally,we find that R&D input and exiting firms among industry are the driving forces for enhancing TFP and increasing wage and unemployment.
基金Project supported by the National Science Council of the People Republic of China(No.2008ZX02104)the State Key Laboratory of Tribology,China(No.SKLT08B08).
文摘Chemical mechanical polishing (CMP) is the most effective wafer global planarization technology. The CMP polishing head is one of the most important components, and zone back pressure control technology is used to design a new generation of polishing head. The quality of polishing not only depends on slurry, but also depends on the precise control of polishing pressures. During the CMP polishing process, the set pressure of each chamber is usually not the same and the presence of a flexible elastic diaphragm causes coupling effects. Because of the coupling effects, the identification of multi-chambers and pressure controls becomes complicated. To solve the coupling problem, this paper presents a new method of multi-chamber decoupled control, and then system identification and control parameter tuning are carried out based on the method. Finally, experiments of multi- chambers inflated at the same time are performed. The experimental results show that the presented decoupling control method is feasible and correct.
基金supported by National Natural Science Foundation of China(Nos.61233004 and 61221003)the National Basic Research Program of China(973 Program)(No.2013CB035500)the Higher Education Research Fund for the Doctoral Program of China(No.20120073130006)
文摘In this paper we address the problem of pressure management in water supply system (WSS) network. The model-based predictive control (MPC) strategies have some important features to deal with WSS. By hydraulic analysis of WSS, the predictive model is derived from the dynamic model and static model of WSS. Through WSS, the consumers' demands are required to be met at all times according to some operational constraints that must be satisfied. The constraints of flow through actuators, the water level of reservoirs and the consumer areas' pressure demand are determined by a specific system. In this work, we develop a constrained MPC controller that considers the zone control of the pressure outputs and incorporates steady state economic targets in the control cost function. The designed management strategies are applied to a case study and simulation results, covering different aspects, are provided. The output nodal pressure can be controlled in the desired zone by optimal scheduling the actuators of the WSS. If the variation range of reservoir's water level is broader, the rate of flow through the actuators is gentle, and vice versa.