In this study,the neutral gas distribution and steady-state discharge under different discharge channel lengths were studied via numerical simulations.The results show that the channel with a length of 22 mm has the a...In this study,the neutral gas distribution and steady-state discharge under different discharge channel lengths were studied via numerical simulations.The results show that the channel with a length of 22 mm has the advantage of comprehensive discharge performance.At this time,the magnetic field intensity at the anode surface is 10%of the peak magnetic field intensity.Further analysis shows that the high-gas-density zone moves outward due to the shortening of the channel length,which optimizes the matching between the gas flow field and the magnetic field,and thus increases the ionization rate.The outward movement of the main ionization zone also reduces the ion loss on the wall surface.Thus,the propellant utilization efficiency can reach a maximum of 96.8%.Moreover,the plasma potential in the main ionization zone will decrease with the shortening of the channel.The excessively short-channel will greatly reduce the voltage utilization efficiency.The thrust is reduced to a minimum of 46.1 m N.Meanwhile,because the anode surface is excessively close to the main ionization zone,the discharge reliability is also difficult to guarantee.It was proved that the performance of Hall thrusters can be optimized by shortening the discharge channel appropriately,and the specific design scheme of short-channel of HEP-1350 PM was defined,which serves as a reference for the optimization design of Hall thruster with large height–radius ratio.The shortchannel design also helps to reduce the thruster axial dimension,further consolidating the advantages of lightweight and large thrust-to-weight ratio of the Hall thruster with large height–radius ratio.展开更多
The memorial hall is an important place to learn red culture in China,which plays a positive role in carrying forward red culture and continuing revolutionary spirit.The outline of the “14^(th) Five-year” plan point...The memorial hall is an important place to learn red culture in China,which plays a positive role in carrying forward red culture and continuing revolutionary spirit.The outline of the “14^(th) Five-year” plan points out that “it should adhere to the integrated development,shape tourism with culture,highlight culture with tourism,and improve the system of integrated development of culture and tourism”.On this basis,it is proposed that the development of memorial halls in the new era needs the integration of culture and tourism.In this paper,the protection status of red culture of Hehan Detachment is investigated,and its existing problems are analyzed.The construction of Hehan Detachment Memorial Hall is taken as research object.The design strategy of the memorial hall is put forward,and rural red culture undertakings and the integrated development of culture and tourism industry are further established and improved.The research could provide a valuable reference for continuing red culture undertakings and innovating the development of culture and tourism industry at present.展开更多
University hall is an important carrier of information exchange and sharing in higher education campuses,and the correct architectural design positioning can improve the value of university halls.There are many differ...University hall is an important carrier of information exchange and sharing in higher education campuses,and the correct architectural design positioning can improve the value of university halls.There are many different features in the design and use of university halls and urban theaters.This paper investigates the feasibility study report and indexes of university hall projects,analyzes the indexes,construction scale and functional positioning of university halls in the pre-design period,summarizes some design suggestions,and believes that the use efficiency of university halls should be improved through intensive and compound construction to meet the needs of the rapid development of Chinas Universitys and universities.展开更多
基金This work is funded by the Defense Industrial Technology Development Program(No.JCKY2019603B005)National Natural Science Foundation of China(Nos.52076054,51777045)the Hunan Science and Technology Innovation Project(No.2019RS1102).
文摘In this study,the neutral gas distribution and steady-state discharge under different discharge channel lengths were studied via numerical simulations.The results show that the channel with a length of 22 mm has the advantage of comprehensive discharge performance.At this time,the magnetic field intensity at the anode surface is 10%of the peak magnetic field intensity.Further analysis shows that the high-gas-density zone moves outward due to the shortening of the channel length,which optimizes the matching between the gas flow field and the magnetic field,and thus increases the ionization rate.The outward movement of the main ionization zone also reduces the ion loss on the wall surface.Thus,the propellant utilization efficiency can reach a maximum of 96.8%.Moreover,the plasma potential in the main ionization zone will decrease with the shortening of the channel.The excessively short-channel will greatly reduce the voltage utilization efficiency.The thrust is reduced to a minimum of 46.1 m N.Meanwhile,because the anode surface is excessively close to the main ionization zone,the discharge reliability is also difficult to guarantee.It was proved that the performance of Hall thrusters can be optimized by shortening the discharge channel appropriately,and the specific design scheme of short-channel of HEP-1350 PM was defined,which serves as a reference for the optimization design of Hall thruster with large height–radius ratio.The shortchannel design also helps to reduce the thruster axial dimension,further consolidating the advantages of lightweight and large thrust-to-weight ratio of the Hall thruster with large height–radius ratio.
基金Sponsored by Stage Achievements of Major Projects of Humanities and Social Sciences in Colleges and Universities of Anhui Province (SK2021ZD0036)。
文摘The memorial hall is an important place to learn red culture in China,which plays a positive role in carrying forward red culture and continuing revolutionary spirit.The outline of the “14^(th) Five-year” plan points out that “it should adhere to the integrated development,shape tourism with culture,highlight culture with tourism,and improve the system of integrated development of culture and tourism”.On this basis,it is proposed that the development of memorial halls in the new era needs the integration of culture and tourism.In this paper,the protection status of red culture of Hehan Detachment is investigated,and its existing problems are analyzed.The construction of Hehan Detachment Memorial Hall is taken as research object.The design strategy of the memorial hall is put forward,and rural red culture undertakings and the integrated development of culture and tourism industry are further established and improved.The research could provide a valuable reference for continuing red culture undertakings and innovating the development of culture and tourism industry at present.
文摘University hall is an important carrier of information exchange and sharing in higher education campuses,and the correct architectural design positioning can improve the value of university halls.There are many different features in the design and use of university halls and urban theaters.This paper investigates the feasibility study report and indexes of university hall projects,analyzes the indexes,construction scale and functional positioning of university halls in the pre-design period,summarizes some design suggestions,and believes that the use efficiency of university halls should be improved through intensive and compound construction to meet the needs of the rapid development of Chinas Universitys and universities.
