The negative ion based neutral beam injector(NNBI)with a beam energy of 400 keV is one of the subsystems at the Comprehensive Research fAcility for Fusion Technology(CRAFT)in China.The distributed capacitance of the h...The negative ion based neutral beam injector(NNBI)with a beam energy of 400 keV is one of the subsystems at the Comprehensive Research fAcility for Fusion Technology(CRAFT)in China.The distributed capacitance of the high-voltage components is an important basis for the design of surge suppression devices at CRAFT NNBI.This study conducted calculations of distributed capacitance for the key components,including the high-voltage deck,transmission line and isolation transformer in the power supply system using the finite element method.The relationship between the high-voltage deck(HVD)distributed capacitance and the distance from the wall is discussed.The differences in distributed capacitance and energy storage between noncoaxial and coaxial transmission lines are also debated.Finally,the capacitance between the primary and secondary windings of the-400 kV isolation transformer,as well as between the secondary winding and the oil tank casing,was calculated.展开更多
Neutral beam injection(NBI)has been proven as a reliable heating and current drive method for fusion plasma.For the high-energy NBI system(particle energy>150 ke V)of large-scale fusion devices,the negative ion sou...Neutral beam injection(NBI)has been proven as a reliable heating and current drive method for fusion plasma.For the high-energy NBI system(particle energy>150 ke V)of large-scale fusion devices,the negative ion source neutral beam injection(NNBI)system is inevitable,which can obtain an acceptable neutralization efficiency(>55%).But the NNBI system is very complex and challengeable.To explore and master the key NNBI technology for future fusion reactor in China,an NNBI test facility is under development in the framework of the Comprehensive Research Facility for Fusion Technology(CRAFT).The initial goal of CRAFT NNBI facility is to achieve a 2 MW hydrogen neutral beam at the energy of 200–400 ke V for lasting 100 s.In the first operation of the CRAFT NNBI facility,a negative ion source with dual RF drivers was developed and tested.By using the 50 keV accelerator,the long-pulse and highcurrent extractions of negative hydrogen ions have been achieved and the typical values were 55.4 keV,7.3 A(~123 A/m^(2)),105 s and 55.0 keV,14.7 A(~248 A/m^(2)),30 s,respectively.By using the 200 keV accelerator,the megawatt-class negative hydrogen beam has also been achieved(135.9 keV,8.9 A,8 s).The whole process of the gas neutralization of negative ion beam,electric removal of residual ions,and beam transport have been demonstrated experimentally.展开更多
Long pulse operation of high power ion source is the requirement of fusion science research on neutral beam injector. A breakdown of accelerator column is drastically increased when operating with high beam energy and...Long pulse operation of high power ion source is the requirement of fusion science research on neutral beam injector. A breakdown of accelerator column is drastically increased when operating with high beam energy and long beam duration. To extend the pulse length, which was stopped with every breakdown so far, the beam re-starting technology was developed and utilized. As a result, the voltage drop of every power supply due to breakdown was recovered within a time of 90 ms and beam pulse length was extended much longer than the case before this improvement. The details of the beam re-starting technology and the preliminary results were presented in this manuscript.展开更多
Background Compared with traditional thoracotomy,video-assisted thoracoscopic surgery(VATS)has less minor trauma,faster recovery,higher patient compliance,but higher requirements for surgeons.Virtual surgery training ...Background Compared with traditional thoracotomy,video-assisted thoracoscopic surgery(VATS)has less minor trauma,faster recovery,higher patient compliance,but higher requirements for surgeons.Virtual surgery training simulation systems are important and have been widely used in Europe and America.Augmented reality(AR)in surgical training simulation systems significantly improve the training effect of virtual surgical training,although AR technology is still in its initial stage.Mixed reality has gained increased attention in technology-driven modern medicine but has yet to be used in everyday practice.Methods This study proposed an immersive AR lobectomy within a thoracoscope surgery training system,using visual and haptic modeling to study the potential benefits of this critical technology.The content included immersive AR visual rendering,based on the cluster-based extended position-based dynamics algorithm of soft tissue physical modeling.Furthermore,we designed an AR haptic rendering systems,whose model architecture consisted of multi-touch interaction points,including kinesthetic and pressure-sensitive points.Finally,based on the above theoretical research,we developed an AR interactive VATS surgical training platform.Results Twenty-four volunteers were recruited from the First People's Hospital of Yunnan Province to evaluate the VATS training system.Face,content,and construct validation methods were used to assess the tactile sense,visual sense,scene authenticity,and simulator performance.Conclusions The results of our construction validation demonstrate that the simulator is useful in improving novice and surgical skills that can be retained after a certain period of time.The video-assisted thoracoscopic system based on AR developed in this study is effective and can be used as a training device to assist in the development of thoracoscopic skills for novices.展开更多
Background The lack of social activities among the elderly due to physical limitations can result in loneliness and depression. The spread of COVID-19 has made it difficult for the elderly to conduct stable social act...Background The lack of social activities among the elderly due to physical limitations can result in loneliness and depression. The spread of COVID-19 has made it difficult for the elderly to conduct stable social activities, increasing feelings of loneliness. The metaverse is a virtual world that mirrors reality. This allows the elderly to overcome the constraints of reality and perform social activities stably and continuously, providing new ideas for alleviating loneliness. Methods By analyzing their needs, a virtual social center framework for the elderly was proposed in this study. In addition, a prototype system was designed according to this framework. The elderly can socialize in virtual reality with metaverse-related technologies and human–computer interaction tools. Additionally, a test was conducted jointly with the chief physician of the geriatric rehabilitation department of a tertiary hospital. Results The results demonstrated that the mental state of the elderly who had used the virtual social center was significantly better than that of those who had not used it. Conclusions Thus, virtual social centers can help relieve loneliness and depression among the elderly with increasing global epidemics and an aging society. Hence,they have promotional value.展开更多
Using high-frequency onshore wind data from four different heights of a coastal tower,the variations in gust factor with turbulence intensity,height and wind speed were studied under typhoon conditions.The gust factor...Using high-frequency onshore wind data from four different heights of a coastal tower,the variations in gust factor with turbulence intensity,height and wind speed were studied under typhoon conditions.The gust factor increases with increasing turbulence intensity and,most often,can be described by a linear relationship with the turbulence intensity.The gust factor decreases with height and is relatively small compared with those presented in the national codes and other studies.A value of 2.5 is acceptable for the peak factor,which is close to the recommended value of the national code in China.The gust factor increases with increasing wind speed and is also affected by the wind direction.The gust factor has a value to that of previously published results when the wind flows roughly perpendicular to the shoreline,and has a smaller value when the wind flows roughly parallel to the shoreline.The phenomenon is caused by the confinement of shoreline on the sea wave development.Sea waves tend to propagate normal to the shoreline because of the refraction effect.As a result,a shorter roughness length exists in the parallel direction to the shoreline.It can be further explained by the weakness in the momentum flux exchange between the air and sea based on the wave form drag theory when the wind flows parallel to the shoreline.展开更多
基金supported by the Comprehensive Research Facility for Fusion Technology Program of China(No.2018000052-73-01-001228)National Natural Science Foundation of China(No.11975263)Postgraduate Research and Practice Innovation Program of NUAA(No.xcxjh20231501)。
文摘The negative ion based neutral beam injector(NNBI)with a beam energy of 400 keV is one of the subsystems at the Comprehensive Research fAcility for Fusion Technology(CRAFT)in China.The distributed capacitance of the high-voltage components is an important basis for the design of surge suppression devices at CRAFT NNBI.This study conducted calculations of distributed capacitance for the key components,including the high-voltage deck,transmission line and isolation transformer in the power supply system using the finite element method.The relationship between the high-voltage deck(HVD)distributed capacitance and the distance from the wall is discussed.The differences in distributed capacitance and energy storage between noncoaxial and coaxial transmission lines are also debated.Finally,the capacitance between the primary and secondary windings of the-400 kV isolation transformer,as well as between the secondary winding and the oil tank casing,was calculated.
基金supported by the Comprehensive Research Facility for Fusion Technology Program of China(No.2018-000052-73-01-001228)。
文摘Neutral beam injection(NBI)has been proven as a reliable heating and current drive method for fusion plasma.For the high-energy NBI system(particle energy>150 ke V)of large-scale fusion devices,the negative ion source neutral beam injection(NNBI)system is inevitable,which can obtain an acceptable neutralization efficiency(>55%).But the NNBI system is very complex and challengeable.To explore and master the key NNBI technology for future fusion reactor in China,an NNBI test facility is under development in the framework of the Comprehensive Research Facility for Fusion Technology(CRAFT).The initial goal of CRAFT NNBI facility is to achieve a 2 MW hydrogen neutral beam at the energy of 200–400 ke V for lasting 100 s.In the first operation of the CRAFT NNBI facility,a negative ion source with dual RF drivers was developed and tested.By using the 50 keV accelerator,the long-pulse and highcurrent extractions of negative hydrogen ions have been achieved and the typical values were 55.4 keV,7.3 A(~123 A/m^(2)),105 s and 55.0 keV,14.7 A(~248 A/m^(2)),30 s,respectively.By using the 200 keV accelerator,the megawatt-class negative hydrogen beam has also been achieved(135.9 keV,8.9 A,8 s).The whole process of the gas neutralization of negative ion beam,electric removal of residual ions,and beam transport have been demonstrated experimentally.
基金supported by National Natural Science Foundation of China(Nos.11675215,11575240)the Key Program of Research and Development of Hefei Science Center,CAS(No.2016HSC-KPRD002)the National Key R&D Program of China(No.2017YFE300101)
文摘Long pulse operation of high power ion source is the requirement of fusion science research on neutral beam injector. A breakdown of accelerator column is drastically increased when operating with high beam energy and long beam duration. To extend the pulse length, which was stopped with every breakdown so far, the beam re-starting technology was developed and utilized. As a result, the voltage drop of every power supply due to breakdown was recovered within a time of 90 ms and beam pulse length was extended much longer than the case before this improvement. The details of the beam re-starting technology and the preliminary results were presented in this manuscript.
基金the National Science Foundations of China(62062069,62062070,62005235).
文摘Background Compared with traditional thoracotomy,video-assisted thoracoscopic surgery(VATS)has less minor trauma,faster recovery,higher patient compliance,but higher requirements for surgeons.Virtual surgery training simulation systems are important and have been widely used in Europe and America.Augmented reality(AR)in surgical training simulation systems significantly improve the training effect of virtual surgical training,although AR technology is still in its initial stage.Mixed reality has gained increased attention in technology-driven modern medicine but has yet to be used in everyday practice.Methods This study proposed an immersive AR lobectomy within a thoracoscope surgery training system,using visual and haptic modeling to study the potential benefits of this critical technology.The content included immersive AR visual rendering,based on the cluster-based extended position-based dynamics algorithm of soft tissue physical modeling.Furthermore,we designed an AR haptic rendering systems,whose model architecture consisted of multi-touch interaction points,including kinesthetic and pressure-sensitive points.Finally,based on the above theoretical research,we developed an AR interactive VATS surgical training platform.Results Twenty-four volunteers were recruited from the First People's Hospital of Yunnan Province to evaluate the VATS training system.Face,content,and construct validation methods were used to assess the tactile sense,visual sense,scene authenticity,and simulator performance.Conclusions The results of our construction validation demonstrate that the simulator is useful in improving novice and surgical skills that can be retained after a certain period of time.The video-assisted thoracoscopic system based on AR developed in this study is effective and can be used as a training device to assist in the development of thoracoscopic skills for novices.
基金Supported by Supported by the″Jie Bang Gua Shuai″Science and Technology Project of the Henan Province (211110110500)the Scientific and Technological Project in Henan Province,China (No. 222102210030)。
文摘Background The lack of social activities among the elderly due to physical limitations can result in loneliness and depression. The spread of COVID-19 has made it difficult for the elderly to conduct stable social activities, increasing feelings of loneliness. The metaverse is a virtual world that mirrors reality. This allows the elderly to overcome the constraints of reality and perform social activities stably and continuously, providing new ideas for alleviating loneliness. Methods By analyzing their needs, a virtual social center framework for the elderly was proposed in this study. In addition, a prototype system was designed according to this framework. The elderly can socialize in virtual reality with metaverse-related technologies and human–computer interaction tools. Additionally, a test was conducted jointly with the chief physician of the geriatric rehabilitation department of a tertiary hospital. Results The results demonstrated that the mental state of the elderly who had used the virtual social center was significantly better than that of those who had not used it. Conclusions Thus, virtual social centers can help relieve loneliness and depression among the elderly with increasing global epidemics and an aging society. Hence,they have promotional value.
基金supported by the National Key R&D Program of China (Grant No.2023YFC3008501)the Shanghai Science and Technology Commission Project (Grant No.23DZ204701)the Science and Technology Research and Development Project of China Construction Eighth Engineering Division Corp.,LTD. (Grant No.2022-Q-03).
文摘Using high-frequency onshore wind data from four different heights of a coastal tower,the variations in gust factor with turbulence intensity,height and wind speed were studied under typhoon conditions.The gust factor increases with increasing turbulence intensity and,most often,can be described by a linear relationship with the turbulence intensity.The gust factor decreases with height and is relatively small compared with those presented in the national codes and other studies.A value of 2.5 is acceptable for the peak factor,which is close to the recommended value of the national code in China.The gust factor increases with increasing wind speed and is also affected by the wind direction.The gust factor has a value to that of previously published results when the wind flows roughly perpendicular to the shoreline,and has a smaller value when the wind flows roughly parallel to the shoreline.The phenomenon is caused by the confinement of shoreline on the sea wave development.Sea waves tend to propagate normal to the shoreline because of the refraction effect.As a result,a shorter roughness length exists in the parallel direction to the shoreline.It can be further explained by the weakness in the momentum flux exchange between the air and sea based on the wave form drag theory when the wind flows parallel to the shoreline.
