This paper examines the explorations and practices of environmental- economic accounting in the international community, provides a comprehensive overview and evaluation of the nature and research progress of China＇s...This paper examines the explorations and practices of environmental- economic accounting in the international community, provides a comprehensive overview and evaluation of the nature and research progress of China＇s natural resources balance sheet, reviews the relevant systems of China＇s natural resources balance sheet and the development of ecological civilization, identifies the issues in the formulation of natural resources balance sheet and makes suggestions for improvement.展开更多
The Expert Committee of Wild Animal Hunting,an organization under the State Forestry Administration of China,recently approved a group of foreign hunters’applications to shoot wildlife in China. The news has gained m...The Expert Committee of Wild Animal Hunting,an organization under the State Forestry Administration of China,recently approved a group of foreign hunters’applications to shoot wildlife in China. The news has gained much attention across the country. The application was submitted by two domestic travel agencies on behalf of seven foreign hunters,who plan to shoot nine blue sheep and seven Tibetan gazelles in an international hunting ground in west China’s Qinghai Province. Despite the expert committee’s approval,however,the hunters still can’t fire a shot in China until they get an official license from the State Forestry Administration.According to recent news,the administration has declined the application. In China,blue sheep and Tibetan gazelles are ranked as Class 2展开更多
The conventional multilevel inverters(MLIs)have the disadvantages of numerous devices,incapacity of boost,unbalance for capacitor’s voltage,high complexity for control,and etc.Motivated by this issue,a seven-level bo...The conventional multilevel inverters(MLIs)have the disadvantages of numerous devices,incapacity of boost,unbalance for capacitor’s voltage,high complexity for control,and etc.Motivated by this issue,a seven-level boost inverter(7LBI)based on a switched capacitor is presented for singlephase applications in this paper.The proposed 7LBI using only seven transistors can achieve seven output levels,1.5 voltage gain,and natural balance of capacitors’voltages without sensors or other auxiliary methods,which illustrates its suitability for the applications of renewable energy generation.The configuration of topology and operating principles are illustrated in detail.The natural balance of capacitors and capacitance calculations are deduced as well.Moreover,the comparative study is conducted for different types of MLIs.The results illustrate the merits of the proposed 7LBI with respect to reduced devices,lower voltage stress,and less power loss.Finally,a simulation for the proposed 7LBI with PWM modulation is realized based on the theoretical analysis;an experimental prototype is also implemented,verifying multilevel output,boost ability,natural balance for switched capacitors,and performance of transient response.展开更多
文摘This paper examines the explorations and practices of environmental- economic accounting in the international community, provides a comprehensive overview and evaluation of the nature and research progress of China＇s natural resources balance sheet, reviews the relevant systems of China＇s natural resources balance sheet and the development of ecological civilization, identifies the issues in the formulation of natural resources balance sheet and makes suggestions for improvement.
文摘The Expert Committee of Wild Animal Hunting,an organization under the State Forestry Administration of China,recently approved a group of foreign hunters’applications to shoot wildlife in China. The news has gained much attention across the country. The application was submitted by two domestic travel agencies on behalf of seven foreign hunters,who plan to shoot nine blue sheep and seven Tibetan gazelles in an international hunting ground in west China’s Qinghai Province. Despite the expert committee’s approval,however,the hunters still can’t fire a shot in China until they get an official license from the State Forestry Administration.According to recent news,the administration has declined the application. In China,blue sheep and Tibetan gazelles are ranked as Class 2
基金supported by the National Natural Science Foundation of China under Grants 62173148 and 52377186,and Joint Laboratory of Energy Saving and Intelligent Maintenance for Modern Transportations。
文摘The conventional multilevel inverters(MLIs)have the disadvantages of numerous devices,incapacity of boost,unbalance for capacitor’s voltage,high complexity for control,and etc.Motivated by this issue,a seven-level boost inverter(7LBI)based on a switched capacitor is presented for singlephase applications in this paper.The proposed 7LBI using only seven transistors can achieve seven output levels,1.5 voltage gain,and natural balance of capacitors’voltages without sensors or other auxiliary methods,which illustrates its suitability for the applications of renewable energy generation.The configuration of topology and operating principles are illustrated in detail.The natural balance of capacitors and capacitance calculations are deduced as well.Moreover,the comparative study is conducted for different types of MLIs.The results illustrate the merits of the proposed 7LBI with respect to reduced devices,lower voltage stress,and less power loss.Finally,a simulation for the proposed 7LBI with PWM modulation is realized based on the theoretical analysis;an experimental prototype is also implemented,verifying multilevel output,boost ability,natural balance for switched capacitors,and performance of transient response.
