The research and development of a C-band (5712 MHz) high gradient traveling-wave accelerating structure has been in progress for some years at the Shanghai Institute of Applied Physics, Chinese Academy of Sciences. Co...The research and development of a C-band (5712 MHz) high gradient traveling-wave accelerating structure has been in progress for some years at the Shanghai Institute of Applied Physics, Chinese Academy of Sciences. Conceptual design of the accelerating structure has been accomplished, and verified by cold testing an experimental model. The first prototype structure is now ready for high RF power tests. To develop a robust high gradient C-band accelerating structure, an optimized constant gradient structure with a 4 /5 operating mode for future X-ray Free Electron Laser facilities is proposed in this paper. This scheme can improve the breakdown stability and beam quality. The high power RF system, four operating modes and disk iris shape are analyzed and optimized.展开更多
An RF pulse compressor is a device used to convert a long RF pulse to a short one with a much higher peak RF magnitude. SLED can be regarded as the earliest RF pulse compressor to be used in large-scale linear acceler...An RF pulse compressor is a device used to convert a long RF pulse to a short one with a much higher peak RF magnitude. SLED can be regarded as the earliest RF pulse compressor to be used in large-scale linear accelerators. It has been widely studied around the world and applied in the BEPC and BEPCⅡ linac for many years. During routine operation, error and jitter effects will deteriorate the performance of SLED, either on the output electromagnetic wave amplitude or phase. The error effects mainly include the frequency drift induced by cooling water temperature variation and the frequency/Q 0 /β unbalances between the two energy storage cavities caused by mechanical fabrication or microwave tuning. The jitter effects refer to the PSK switching phase and time jitters. In this paper, we re-derive the generalized formulae for the conventional SLED used in the BEPCⅡ linac, and the error and jitter effects on SLED performance are also investigated.展开更多
The critically ill patient is capable of presenting a multiple organ dysfunction syndrome (MODS) caused by different diseases, which can be infectious (sepsis, septic shock) as well as non-infectious (pancreatitis, la...The critically ill patient is capable of presenting a multiple organ dysfunction syndrome (MODS) caused by different diseases, which can be infectious (sepsis, septic shock) as well as non-infectious (pancreatitis, large surgeries, traumatic injuries, burn patients and brain injuries), this syndrome is characterized by global hemodynamic and organ perfusion alterations accompanied by an uncontrolled and marked inflammatory response unresponsive to pharmacological treatment due to which extracorporeal organ support can be a viable option. Acute renal lesion can occur in up to 60% of patients receiving intensive care, and close to 10% - 20% require renal replacement therapy (RRT) globally this can be provided as peritoneal dialysis (PD) or intermittent hemodialysis (IHD), continuous renal replacement therapy (CRRT), hybrid therapies known as sustained slow efficiency dialysis (SLED), which combines the benefits IHD and CRRT, slow continuous ultrafiltration (SCUF). Extracorporeal membrane oxygenation (ECMO) and extracorporeal elimination of CO<sub>2</sub>, have been used more frequently lately, these are temporal artificial support used for respiratory and/or cardiac insufficiency that is refractory to conventional treatment. Acute liver failure in adults has a mortality rate close to 50% furthermore one-third of patients hospitalized for cirrhosis are likely to progress to acute liver failure which will drastically increase its mortality. Based on concepts of albumin dialysis, one of its most known is the following: Molecular Adsorbent Recirculating System (MARS), Fractionated Plasma Separation and Absorption—FPSA (Prometheus<sup>®</sup>) and also, hemoperfusion with different cartridges used in different extracorporeal therapies, used in liver failure, rhabdomyolysis, cytokine release syndrome and more in the context of the pandemic covid19. The objective of this review is to know the different extracorporeal therapies and the therapeutic utility in critical patients.展开更多
The nitrogen alloyed ultralow carbon stainless steel is a good candidate material for primary loop pipes of AP1000 nuclear power plant. These pipes arc manufactured by hot forging, during which dynamic recrystallizati...The nitrogen alloyed ultralow carbon stainless steel is a good candidate material for primary loop pipes of AP1000 nuclear power plant. These pipes arc manufactured by hot forging, during which dynamic recrystallization acts as the most important microstructural evolution mechanism. A physically based model was proposed to describe and predict the microstructural evolution in the hot forging process of those pipes. In this model, the coupled effects of dislocation density change, dynamic recovery, dynamic recrystallization and grain orientation function were con sidered. Besides, physically based simulation experiments were conducted on a Gleeble 3500 thermo-mcchanical sire ulator, and the specimens after deformation were observed by optical metallography （OM） and clectron back scat toted diffraction （EBSD） method. The results confirm that dynamic recrystallization is easy to occur with increasing deformation temperature or strain rate. The grains become much finer after full dynamic recrystallization. The model shows a good agreement with experimental results obtained by OM and EBSD in terms of stress strain curves, grain size, and recrystallization kinetics. Besides, this model obtains an acceptable accuracy and a wide applying scope for engineering calculation.展开更多
An S band SLED-type pulse compressor has been manufactured by the Institute of High Energy Physics,Beijing, trying to reach 100 MW maximum input power, which means the output peak power is about 500 MW at the phase re...An S band SLED-type pulse compressor has been manufactured by the Institute of High Energy Physics,Beijing, trying to reach 100 MW maximum input power, which means the output peak power is about 500 MW at the phase reversal time. To improve the reliability at very high power, amplitude modulation and phase modulation with flat-top output are considered, and RF modulation studies on the S-band SLED are presented in this paper.Furthermore, a method is developed using the CST Microwave Studio transient solver to simulate the time response of the pulse compressor, which can verify the modulation theory. In addition, the experimental setup was constructed and the flat-top output obtained in low power tests. Both amplitude modulation and phase modulation methods can give flat-top output, and the average power gain for both methods is almost the same.展开更多
SLAC energy doubler （SLED） type radio-frequency pulse compressors are widely used in large-scale particle accelerators for converting long-duration moderate-power input pulses into short-duration high-power output p...SLAC energy doubler （SLED） type radio-frequency pulse compressors are widely used in large-scale particle accelerators for converting long-duration moderate-power input pulses into short-duration high-power output pulses. Phase shift keying （PSK） is one of the key components in SLED pulse compression systems. Performance of the PSK will influence the output characteristics of the SLED, such as the rise-time of the output pulse, maximal peak power gain, and energy efficiency. In this paper, a high power microwave source based on power combining and pulse compression of conventional klystrons is introduced. The effects of nonideal PSK with slow switching speed and PSK without power output during the switching process are investigated, and the experimental results with nonideal PSK agree well with the analytical results.展开更多
SLED （SLAC Energy Doubler） is a crucial component for the C-band microwave acceleration unit of a soft X-ray Free Electron Laser （SXFEL）. To study the behavior of SLED, a mathematical model is commonly built and a...SLED （SLAC Energy Doubler） is a crucial component for the C-band microwave acceleration unit of a soft X-ray Free Electron Laser （SXFEL）. To study the behavior of SLED, a mathematical model is commonly built and analyzed. In this paper, a new method is proposed to build the model of SLED at the Shanghai Institute of Applied Physics. With this method, the parameters of the two cavities can be analyzed separately. Also it is suitable to study parameter optimization of SLED and analyze the effect from the parameters variations. Simulation results of our method are also presented.展开更多
当前IMS Learning Design(IMS LD)规范中虽然整合了QTI(Question and Test Interoperability)规范,但是在当前的播放器中却没有很好地整合QTI服务,这就阻碍了播放器和QTI之间的通信,从而不能很好地实现QTI服务。文中针对SLeD体系结构,...当前IMS Learning Design(IMS LD)规范中虽然整合了QTI(Question and Test Interoperability)规范,但是在当前的播放器中却没有很好地整合QTI服务,这就阻碍了播放器和QTI之间的通信,从而不能很好地实现QTI服务。文中针对SLeD体系结构,在该体系结构中加入了中间软件层,利用这个中间软件层实现了播放阶段QTI和播放器的通信。展开更多
基金supported by the Program of the Shanghai Subject Chief Scientist-Natural Science Foundation (08XD1405400)
文摘The research and development of a C-band (5712 MHz) high gradient traveling-wave accelerating structure has been in progress for some years at the Shanghai Institute of Applied Physics, Chinese Academy of Sciences. Conceptual design of the accelerating structure has been accomplished, and verified by cold testing an experimental model. The first prototype structure is now ready for high RF power tests. To develop a robust high gradient C-band accelerating structure, an optimized constant gradient structure with a 4 /5 operating mode for future X-ray Free Electron Laser facilities is proposed in this paper. This scheme can improve the breakdown stability and beam quality. The high power RF system, four operating modes and disk iris shape are analyzed and optimized.
基金Supported by the National Natural Science Foundation of China (11105164)
文摘An RF pulse compressor is a device used to convert a long RF pulse to a short one with a much higher peak RF magnitude. SLED can be regarded as the earliest RF pulse compressor to be used in large-scale linear accelerators. It has been widely studied around the world and applied in the BEPC and BEPCⅡ linac for many years. During routine operation, error and jitter effects will deteriorate the performance of SLED, either on the output electromagnetic wave amplitude or phase. The error effects mainly include the frequency drift induced by cooling water temperature variation and the frequency/Q 0 /β unbalances between the two energy storage cavities caused by mechanical fabrication or microwave tuning. The jitter effects refer to the PSK switching phase and time jitters. In this paper, we re-derive the generalized formulae for the conventional SLED used in the BEPCⅡ linac, and the error and jitter effects on SLED performance are also investigated.
文摘The critically ill patient is capable of presenting a multiple organ dysfunction syndrome (MODS) caused by different diseases, which can be infectious (sepsis, septic shock) as well as non-infectious (pancreatitis, large surgeries, traumatic injuries, burn patients and brain injuries), this syndrome is characterized by global hemodynamic and organ perfusion alterations accompanied by an uncontrolled and marked inflammatory response unresponsive to pharmacological treatment due to which extracorporeal organ support can be a viable option. Acute renal lesion can occur in up to 60% of patients receiving intensive care, and close to 10% - 20% require renal replacement therapy (RRT) globally this can be provided as peritoneal dialysis (PD) or intermittent hemodialysis (IHD), continuous renal replacement therapy (CRRT), hybrid therapies known as sustained slow efficiency dialysis (SLED), which combines the benefits IHD and CRRT, slow continuous ultrafiltration (SCUF). Extracorporeal membrane oxygenation (ECMO) and extracorporeal elimination of CO<sub>2</sub>, have been used more frequently lately, these are temporal artificial support used for respiratory and/or cardiac insufficiency that is refractory to conventional treatment. Acute liver failure in adults has a mortality rate close to 50% furthermore one-third of patients hospitalized for cirrhosis are likely to progress to acute liver failure which will drastically increase its mortality. Based on concepts of albumin dialysis, one of its most known is the following: Molecular Adsorbent Recirculating System (MARS), Fractionated Plasma Separation and Absorption—FPSA (Prometheus<sup>®</sup>) and also, hemoperfusion with different cartridges used in different extracorporeal therapies, used in liver failure, rhabdomyolysis, cytokine release syndrome and more in the context of the pandemic covid19. The objective of this review is to know the different extracorporeal therapies and the therapeutic utility in critical patients.
基金Item Sponsored by National High-tech Research and Development Program of China(2012AA03A507,2012AA050901)National Science and Technology Major Project of China(2011ZX06004)
文摘The nitrogen alloyed ultralow carbon stainless steel is a good candidate material for primary loop pipes of AP1000 nuclear power plant. These pipes arc manufactured by hot forging, during which dynamic recrystallization acts as the most important microstructural evolution mechanism. A physically based model was proposed to describe and predict the microstructural evolution in the hot forging process of those pipes. In this model, the coupled effects of dislocation density change, dynamic recovery, dynamic recrystallization and grain orientation function were con sidered. Besides, physically based simulation experiments were conducted on a Gleeble 3500 thermo-mcchanical sire ulator, and the specimens after deformation were observed by optical metallography （OM） and clectron back scat toted diffraction （EBSD） method. The results confirm that dynamic recrystallization is easy to occur with increasing deformation temperature or strain rate. The grains become much finer after full dynamic recrystallization. The model shows a good agreement with experimental results obtained by OM and EBSD in terms of stress strain curves, grain size, and recrystallization kinetics. Besides, this model obtains an acceptable accuracy and a wide applying scope for engineering calculation.
基金Supported by National Natural Science Foundation of China(11475201)
文摘An S band SLED-type pulse compressor has been manufactured by the Institute of High Energy Physics,Beijing, trying to reach 100 MW maximum input power, which means the output peak power is about 500 MW at the phase reversal time. To improve the reliability at very high power, amplitude modulation and phase modulation with flat-top output are considered, and RF modulation studies on the S-band SLED are presented in this paper.Furthermore, a method is developed using the CST Microwave Studio transient solver to simulate the time response of the pulse compressor, which can verify the modulation theory. In addition, the experimental setup was constructed and the flat-top output obtained in low power tests. Both amplitude modulation and phase modulation methods can give flat-top output, and the average power gain for both methods is almost the same.
文摘SLAC energy doubler （SLED） type radio-frequency pulse compressors are widely used in large-scale particle accelerators for converting long-duration moderate-power input pulses into short-duration high-power output pulses. Phase shift keying （PSK） is one of the key components in SLED pulse compression systems. Performance of the PSK will influence the output characteristics of the SLED, such as the rise-time of the output pulse, maximal peak power gain, and energy efficiency. In this paper, a high power microwave source based on power combining and pulse compression of conventional klystrons is introduced. The effects of nonideal PSK with slow switching speed and PSK without power output during the switching process are investigated, and the experimental results with nonideal PSK agree well with the analytical results.
文摘SLED （SLAC Energy Doubler） is a crucial component for the C-band microwave acceleration unit of a soft X-ray Free Electron Laser （SXFEL）. To study the behavior of SLED, a mathematical model is commonly built and analyzed. In this paper, a new method is proposed to build the model of SLED at the Shanghai Institute of Applied Physics. With this method, the parameters of the two cavities can be analyzed separately. Also it is suitable to study parameter optimization of SLED and analyze the effect from the parameters variations. Simulation results of our method are also presented.
文摘当前IMS Learning Design(IMS LD)规范中虽然整合了QTI(Question and Test Interoperability)规范,但是在当前的播放器中却没有很好地整合QTI服务,这就阻碍了播放器和QTI之间的通信,从而不能很好地实现QTI服务。文中针对SLeD体系结构,在该体系结构中加入了中间软件层,利用这个中间软件层实现了播放阶段QTI和播放器的通信。
