From the perspective of agricultural insurance agency,this paper focuses on the study of operational efficiency of agricultural insurance agency,and analyzes the operational efficiency of agricultural insurance agency...From the perspective of agricultural insurance agency,this paper focuses on the study of operational efficiency of agricultural insurance agency,and analyzes the operational efficiency of agricultural insurance agency and its influencing factors,in order to improve the operational efficiency of agricultural insurance agency,better supply agricultural insurance and achieve the policy effect of agricultural insurance.The results of this paper are as follows:( i) Either comprehensive operational efficiency or scale efficiency of Chinese-funded agency is higher than that of foreign-funded agency,but its pure technical efficiency is lower than that of foreign-funded agency,indicating that the managerial decision ability of Chinese-funded agency is weaker than that of foreign-funded agency,and needs to be improved;( ii) The operational efficiency of professional agricultural insurance agency is higher than that of comprehensive agricultural insurance agency,and the agricultural insurance agency is greatly affected by environmental factors;( iii) The operating time of agricultural insurance agency is proportional to its operational efficiency;( iv) The quality of employees is positively correlated with the capital and cost input difference,but negatively correlated with the difference in the number of employees. Therefore,it is necessary to pay attention to the improvement of employees' working efficiency while laying emphasis on employees' quality.展开更多
The use of an electrical network as close as possible to its limits can lead to its instability in the event of a high amplitude disturbance. The damping of system oscillations can be achieved by conventional means of...The use of an electrical network as close as possible to its limits can lead to its instability in the event of a high amplitude disturbance. The damping of system oscillations can be achieved by conventional means of voltage and speed regulation but also by FACTS (Flexible AC Transmission Systems) devices, which are increasingly used in power networks. In this work, optimal control coordination between a hybrid power flow controller and a three-level inverter was used to improve the transient stability of a transmission line. The UPFC is a combination of a serial compensator (SSSC) and a parallel compensator (STATCOM) both connected to a DC-LINK DC bus. The SSSC acts as a voltage source for the network and injects a voltage that can be adjusted in phase and amplitude in addition to the network voltage;the STATCOM acts as a current source. The approach used is tested in the Matlab Simulink environment on a single machine network. Optimal controller tuning gives a better transient stability improvement by reducing the transport angle oscillations from 248.17% to 9.85%.展开更多
This paper uses a three-stage DEA model to measure the land use efficiency of the three major urban agglomerations in the Yangtze River Delta,Beijing-Tianjin-Hebei,and the Pearl River Delta from 2007 to 2018.The follo...This paper uses a three-stage DEA model to measure the land use efficiency of the three major urban agglomerations in the Yangtze River Delta,Beijing-Tianjin-Hebei,and the Pearl River Delta from 2007 to 2018.The following conclusions are drawn through research:first,the urban land use efficiency of the three major urban agglomerations in the Yangtze River Delta,Beijing-Tianjin-Hebei,and the Pearl River Delta all showed a downward trend,with the rates of decline being 6.06%,2.86%,and 24.34%respectively.In particular,the Pearl River Delta urban agglomeration had the largest decline.Second,the overall urban land use efficiency of the Beijing-Tianjin-Hebei urban agglomeration is relatively high,and the amount of redundancy is relatively small.The rate of decline is significantly lower than the urban land use efficiency of the two major urban agglomerations in the Yangtze River Delta and the Pearl River Delta.The land use efficiency of the Yangtze River Delta and Pearl River Delta urban agglomerations is in a state of continuous decline.Third,the proportion of cities with the effectiveness of returns to scale of urban land use efficiency in the three major urban agglomerations has decreased by 10.53%,10%,and 33.34%,respectively.The Pearl River Delta has the largest decline.Fourth,the land use efficiency of the Yangtze River Delta urban agglomeration is quite different.The central-peripheral phenomenon is evident for the Beijing-Tianjin-Hebei urban agglomerations and the Pearl River Delta urban agglomerations.展开更多
Objective: To investigate the effects of standardized three-stage rehabilitation combined with edaravone therapy on the neurotrophic state and oxidative stress injury in patients with cerebral infarction. Methods: A t...Objective: To investigate the effects of standardized three-stage rehabilitation combined with edaravone therapy on the neurotrophic state and oxidative stress injury in patients with cerebral infarction. Methods: A total of 90 patients with acute cerebral infarction who were treated in the hospital between May 2015 and April 2017 were divided into control group (n=45) and observation group (n=45) by random number table. Control group received edaravone therapy, and observation group received standardized three-stage rehabilitation combined with edaravone therapy. The differences in neurotrophic state and oxidative stress injury were compared between the two groups before and after treatment. Results: There was no statistically significant difference in serum levels of neurotrophic indexes and oxidative stress indexes between the two groups before treatment. After treatment, serum neurotrophic indexes BDNF and NGF levels of observation group were higher than those of control group;serum oxidation indexes AOPPs, LHP and MDA levels were lower than those of control group whereas SOD, CAT and T-AOC levels were higher than those of control group. Conclusion:Standardized three-stage rehabilitation combined with edaravone therapy can effectively optimize the neurotrophic state and inhibit the oxidative stress in patients with cerebral infarction.展开更多
As the non-periodic inspections are common in practice,a two-stage inspection model based on a three-stage failure process is proposed. The two-stage inspection means that the system is inspected with the first inspec...As the non-periodic inspections are common in practice,a two-stage inspection model based on a three-stage failure process is proposed. The two-stage inspection means that the system is inspected with the first inspection interval T_1 and the second inspection interval T_2. Because of the three color schemes commonly used in industry,three stages are divided by the system lifetime:normal, minor defective and severe defective stages. Upon the failure of the system,replacement is carried out. Maintenance is done once identifying the severe defective stage. However,when the minor defective stage is identified by the second inspection interval T_2,action of halving the subsequent inspection interval is adopted.Otherwise,no action is required. Our objective function is to optimize the inspection intervals so as to minimize the expected cost per unit time. Finally,a numerical example is presented to illustrate the effectiveness of the proposed model.展开更多
Objective Rapakivi granites,characterized by rapakivi texture,Atype granite feature and an anorogenic setting,commonly occur in the Proterozoic of the Northern Hemisphere（Fig.la）.Recently,more and more Phanerozoic r...Objective Rapakivi granites,characterized by rapakivi texture,Atype granite feature and an anorogenic setting,commonly occur in the Proterozoic of the Northern Hemisphere（Fig.la）.Recently,more and more Phanerozoic rapakivi granite suites have been identified and some even occur in orogenic belts.Significantly,three-stage,Proterozoic.展开更多
In response to the strategic call for the " Great Protection" of the Yangtze River Economic Belt and to fulfill the important historical tasks assigned by the state to the provinces and cities of the area,th...In response to the strategic call for the " Great Protection" of the Yangtze River Economic Belt and to fulfill the important historical tasks assigned by the state to the provinces and cities of the area,the Yangtze River Economic Belt is adjusting the agricultural industry structure,optimizing the input-output ratio,and ensuring stable and sustainable agricultural production. Based on the combination of the three-stage Data Envelopment Analysis( DEA) model and cluster analysis,this study examined the Yangtze River Economic Belt from 2008 to 2018 to measure its agricultural production efficiency and to analyze its temporal and spatial characteristics. Studies showed that exogenous environmental factors significantly( P < 5%) impacted agricultural production efficiency in the Yangtze River Economic Zone,and there were temporal and spatial differences. These included:(1) after excluding environmental factors,the overall agricultural production efficiency of the Yangtze River Economic Zone had improved. Sichuan Province and Jiangsu Province were at the forefront of efficiency,whereas the agricultural production efficiency of Shanghai had declined obviously.(2) The agricultural production efficiency of the Yangtze River Economic Belt varied year by year,with fluctuating development. The middle reaches of the Yangtze River had advanced agricultural production efficiency more than the upstream and downstream regions,and the agricultural production efficiency of the individual provinces did not match their economic and social development.(3) Increases in labor,land,irrigation,and other input factors increased agriculture production efficiency,and there was no correlation between fiscal investment,per capita gross domestic product( GDP) and agricultural production efficiency,while the disaster-affected area had a significantly negative impact on agricultural production efficiency.展开更多
A novel frequency compensation technique for three-stage amplifier with dual complex pole-zero (DCP) cancellation is proposed. It uses one pair of complex zeros to cancel one pair of complex poles, resulting in featur...A novel frequency compensation technique for three-stage amplifier with dual complex pole-zero (DCP) cancellation is proposed. It uses one pair of complex zeros to cancel one pair of complex poles, resulting in feature that frequency response of the three-stage amplifier exhibits that of a single-pole system. Thus the gain-bandwidth (GBW) is expected to be increased several times compared to the conventional nested miller compensation (NMC) approach. Moreover, this technique requires only one very small compensation capacitor even when driving a big load capacitor. A GBW 4.63 MHz, DC gain 100 dB, PM 90o and power dissipation 0.87 mW can be achieved for a load capacitor 100 pF with a single Miller compensation capacitor 2 pF at a ±1V supply in a standard 0.6-μm CMOS technology.展开更多
电感储能型脉冲电源是目前电磁发射技术的研究热点,提升装置储能密度对于推动电感储能型脉冲电源的应用和研究具有重要意义。本文介绍了一种适用于电感储能型脉冲电源的名为meat grinder with SECT的新电路,并对该电路进行了详细的原理...电感储能型脉冲电源是目前电磁发射技术的研究热点,提升装置储能密度对于推动电感储能型脉冲电源的应用和研究具有重要意义。本文介绍了一种适用于电感储能型脉冲电源的名为meat grinder with SECT的新电路,并对该电路进行了详细的原理分析,指出该电路兼具电流关断能力强和拓扑结构简单的优点。通过仿真将meat grinder with SECT和STRETCH meat grinder、STRETCH meat grinder with ICCOS这两种主流电路进行了性能比较,发现meat grinder with SECT电路在保持电气性能不变的同时,成本最低,体积最小。基于meat grinder with SECT电路,本文研制了50k J电感储能型脉冲电源并进行了试验测试,测试结果达到了预期目标。展开更多
This article mainly introduces the innovative internship and training model of vocational colleges,including five aspects such as“four-party collaboration,three-stage progression,four-way integration,value-added eval...This article mainly introduces the innovative internship and training model of vocational colleges,including five aspects such as“four-party collaboration,three-stage progression,four-way integration,value-added evaluation,and double selection and promotion.”The model aims to improve students’practical skills and professional quality to better adapt to market demand and social development.The article also presents the prospects of the future internship and training model,including strengthening cooperation and communication with industry enterprises,focusing on students’personalized development and practical skill cultivation,and establishing a scientific and objective evaluation and feedback mechanism.展开更多
文摘From the perspective of agricultural insurance agency,this paper focuses on the study of operational efficiency of agricultural insurance agency,and analyzes the operational efficiency of agricultural insurance agency and its influencing factors,in order to improve the operational efficiency of agricultural insurance agency,better supply agricultural insurance and achieve the policy effect of agricultural insurance.The results of this paper are as follows:( i) Either comprehensive operational efficiency or scale efficiency of Chinese-funded agency is higher than that of foreign-funded agency,but its pure technical efficiency is lower than that of foreign-funded agency,indicating that the managerial decision ability of Chinese-funded agency is weaker than that of foreign-funded agency,and needs to be improved;( ii) The operational efficiency of professional agricultural insurance agency is higher than that of comprehensive agricultural insurance agency,and the agricultural insurance agency is greatly affected by environmental factors;( iii) The operating time of agricultural insurance agency is proportional to its operational efficiency;( iv) The quality of employees is positively correlated with the capital and cost input difference,but negatively correlated with the difference in the number of employees. Therefore,it is necessary to pay attention to the improvement of employees' working efficiency while laying emphasis on employees' quality.
文摘The use of an electrical network as close as possible to its limits can lead to its instability in the event of a high amplitude disturbance. The damping of system oscillations can be achieved by conventional means of voltage and speed regulation but also by FACTS (Flexible AC Transmission Systems) devices, which are increasingly used in power networks. In this work, optimal control coordination between a hybrid power flow controller and a three-level inverter was used to improve the transient stability of a transmission line. The UPFC is a combination of a serial compensator (SSSC) and a parallel compensator (STATCOM) both connected to a DC-LINK DC bus. The SSSC acts as a voltage source for the network and injects a voltage that can be adjusted in phase and amplitude in addition to the network voltage;the STATCOM acts as a current source. The approach used is tested in the Matlab Simulink environment on a single machine network. Optimal controller tuning gives a better transient stability improvement by reducing the transport angle oscillations from 248.17% to 9.85%.
文摘This paper uses a three-stage DEA model to measure the land use efficiency of the three major urban agglomerations in the Yangtze River Delta,Beijing-Tianjin-Hebei,and the Pearl River Delta from 2007 to 2018.The following conclusions are drawn through research:first,the urban land use efficiency of the three major urban agglomerations in the Yangtze River Delta,Beijing-Tianjin-Hebei,and the Pearl River Delta all showed a downward trend,with the rates of decline being 6.06%,2.86%,and 24.34%respectively.In particular,the Pearl River Delta urban agglomeration had the largest decline.Second,the overall urban land use efficiency of the Beijing-Tianjin-Hebei urban agglomeration is relatively high,and the amount of redundancy is relatively small.The rate of decline is significantly lower than the urban land use efficiency of the two major urban agglomerations in the Yangtze River Delta and the Pearl River Delta.The land use efficiency of the Yangtze River Delta and Pearl River Delta urban agglomerations is in a state of continuous decline.Third,the proportion of cities with the effectiveness of returns to scale of urban land use efficiency in the three major urban agglomerations has decreased by 10.53%,10%,and 33.34%,respectively.The Pearl River Delta has the largest decline.Fourth,the land use efficiency of the Yangtze River Delta urban agglomeration is quite different.The central-peripheral phenomenon is evident for the Beijing-Tianjin-Hebei urban agglomerations and the Pearl River Delta urban agglomerations.
文摘Objective: To investigate the effects of standardized three-stage rehabilitation combined with edaravone therapy on the neurotrophic state and oxidative stress injury in patients with cerebral infarction. Methods: A total of 90 patients with acute cerebral infarction who were treated in the hospital between May 2015 and April 2017 were divided into control group (n=45) and observation group (n=45) by random number table. Control group received edaravone therapy, and observation group received standardized three-stage rehabilitation combined with edaravone therapy. The differences in neurotrophic state and oxidative stress injury were compared between the two groups before and after treatment. Results: There was no statistically significant difference in serum levels of neurotrophic indexes and oxidative stress indexes between the two groups before treatment. After treatment, serum neurotrophic indexes BDNF and NGF levels of observation group were higher than those of control group;serum oxidation indexes AOPPs, LHP and MDA levels were lower than those of control group whereas SOD, CAT and T-AOC levels were higher than those of control group. Conclusion:Standardized three-stage rehabilitation combined with edaravone therapy can effectively optimize the neurotrophic state and inhibit the oxidative stress in patients with cerebral infarction.
文摘As the non-periodic inspections are common in practice,a two-stage inspection model based on a three-stage failure process is proposed. The two-stage inspection means that the system is inspected with the first inspection interval T_1 and the second inspection interval T_2. Because of the three color schemes commonly used in industry,three stages are divided by the system lifetime:normal, minor defective and severe defective stages. Upon the failure of the system,replacement is carried out. Maintenance is done once identifying the severe defective stage. However,when the minor defective stage is identified by the second inspection interval T_2,action of halving the subsequent inspection interval is adopted.Otherwise,no action is required. Our objective function is to optimize the inspection intervals so as to minimize the expected cost per unit time. Finally,a numerical example is presented to illustrate the effectiveness of the proposed model.
基金supported by the National Natural Science Foundation of China(grants No.41172062, 40872054 and 40372043)the China Geological Survey(grant No.1212010811033)
文摘Objective Rapakivi granites,characterized by rapakivi texture,Atype granite feature and an anorogenic setting,commonly occur in the Proterozoic of the Northern Hemisphere（Fig.la）.Recently,more and more Phanerozoic rapakivi granite suites have been identified and some even occur in orogenic belts.Significantly,three-stage,Proterozoic.
基金Supported by the Strategic Leading Science and Technology Project (Class A)of Chinese Academy of Sciences (XDA23020101)the National Natural Science Foundation of China (41801129)。
文摘In response to the strategic call for the " Great Protection" of the Yangtze River Economic Belt and to fulfill the important historical tasks assigned by the state to the provinces and cities of the area,the Yangtze River Economic Belt is adjusting the agricultural industry structure,optimizing the input-output ratio,and ensuring stable and sustainable agricultural production. Based on the combination of the three-stage Data Envelopment Analysis( DEA) model and cluster analysis,this study examined the Yangtze River Economic Belt from 2008 to 2018 to measure its agricultural production efficiency and to analyze its temporal and spatial characteristics. Studies showed that exogenous environmental factors significantly( P < 5%) impacted agricultural production efficiency in the Yangtze River Economic Zone,and there were temporal and spatial differences. These included:(1) after excluding environmental factors,the overall agricultural production efficiency of the Yangtze River Economic Zone had improved. Sichuan Province and Jiangsu Province were at the forefront of efficiency,whereas the agricultural production efficiency of Shanghai had declined obviously.(2) The agricultural production efficiency of the Yangtze River Economic Belt varied year by year,with fluctuating development. The middle reaches of the Yangtze River had advanced agricultural production efficiency more than the upstream and downstream regions,and the agricultural production efficiency of the individual provinces did not match their economic and social development.(3) Increases in labor,land,irrigation,and other input factors increased agriculture production efficiency,and there was no correlation between fiscal investment,per capita gross domestic product( GDP) and agricultural production efficiency,while the disaster-affected area had a significantly negative impact on agricultural production efficiency.
文摘A novel frequency compensation technique for three-stage amplifier with dual complex pole-zero (DCP) cancellation is proposed. It uses one pair of complex zeros to cancel one pair of complex poles, resulting in feature that frequency response of the three-stage amplifier exhibits that of a single-pole system. Thus the gain-bandwidth (GBW) is expected to be increased several times compared to the conventional nested miller compensation (NMC) approach. Moreover, this technique requires only one very small compensation capacitor even when driving a big load capacitor. A GBW 4.63 MHz, DC gain 100 dB, PM 90o and power dissipation 0.87 mW can be achieved for a load capacitor 100 pF with a single Miller compensation capacitor 2 pF at a ±1V supply in a standard 0.6-μm CMOS technology.
文摘电感储能型脉冲电源是目前电磁发射技术的研究热点,提升装置储能密度对于推动电感储能型脉冲电源的应用和研究具有重要意义。本文介绍了一种适用于电感储能型脉冲电源的名为meat grinder with SECT的新电路,并对该电路进行了详细的原理分析,指出该电路兼具电流关断能力强和拓扑结构简单的优点。通过仿真将meat grinder with SECT和STRETCH meat grinder、STRETCH meat grinder with ICCOS这两种主流电路进行了性能比较,发现meat grinder with SECT电路在保持电气性能不变的同时,成本最低,体积最小。基于meat grinder with SECT电路,本文研制了50k J电感储能型脉冲电源并进行了试验测试,测试结果达到了预期目标。
基金Special Project for Research on Vocational Education and Industrial Talent in Shandong Province in 2023:General Fund Project“Innovative Research on the‘Four-Way Integration,Three-Stage Progression,Four-Way Progression,Value-Added Evaluation,Double Selection and Promotion’Internship Training Mode Under the Reform of the Modern Vocational Education System Construction”(Project number:2023ZX058)。
文摘This article mainly introduces the innovative internship and training model of vocational colleges,including five aspects such as“four-party collaboration,three-stage progression,four-way integration,value-added evaluation,and double selection and promotion.”The model aims to improve students’practical skills and professional quality to better adapt to market demand and social development.The article also presents the prospects of the future internship and training model,including strengthening cooperation and communication with industry enterprises,focusing on students’personalized development and practical skill cultivation,and establishing a scientific and objective evaluation and feedback mechanism.
