This paper deals with an innovative low-loss AC switch, named as TBBS （transistor based bidirectional switch）, based on the association of super-gain BJTs developed by the GREMAN laboratory. The main characterizatio...This paper deals with an innovative low-loss AC switch, named as TBBS （transistor based bidirectional switch）, based on the association of super-gain BJTs developed by the GREMAN laboratory. The main characterization results of the super-gain BJT are reminded to identify the key parameters that are essential to build the TBBS. A complete characterization database in static mode of this new AC switch is discussed. In particular, its forward and reverse-biased features have been measured to see the evolution of the DC current gain as a function of the current density. The TBBS makes sense when using the super-gain BJT （bipolar junction transistor） in reverse mode. It means that the reverse DC current gain has to be sufficient （at least higher than l compared with the conventional BJT one）. This new AC switch is bidirectional in current and voltage, totally controllable （turn-on and turn-off） and the most attractive solution in terms of on-state power losses. Further, its manufacturing process is as easier as existing device such as triac.展开更多
The Ordovician fracture-vug carbonate reservoirs of Tarim Basin,are featured by developed vugs,caves and fractures.The strong heterogeneity results in huge uncertainty when these reservoirs are quantitatively characte...The Ordovician fracture-vug carbonate reservoirs of Tarim Basin,are featured by developed vugs,caves and fractures.The strong heterogeneity results in huge uncertainty when these reservoirs are quantitatively characterized using merely static seismic data.The effective quantitative characterization of the reservoirs has been an urgent problem to be solved.This study creatively proposes the"second quantitative characterization"technique with the combination of dynamic and static data based on the primary static quantitative characterization and fully considering lots of key influence factors when conducting characterization.In this technique,dynamic analysis methods such as well testing,production rate transient analysis,dynamic reserve evaluation and dynamic connectivity evaluation are used to get understandings on this kind of reservoir.These understandings are used as statistical parameters to constrain the inversion of seismic wave impedance to improve the relationship between wave impedance and porosity and determine the fracture-vug morphology,calculate dynamic reserves,and then a more accurate fracture-vugmodel can be selected and used to calculate the oil-water contact inversely based on the results of"second quantitative characterization".This method can lower the uncertainties in the primary quantitative characterization of fracture-vug reservoirs,enhance the accuracy of characterization results significantly,and has achieved good application results in the fracture-vug carbonate reservoirs of Tarim Basin.展开更多
Nowadays,mild hypothermia is widely used in the fields of post-cardiac arrest resuscitation,stroke,cerebral hemorrhage,large-scale cerebral infarction,and craniocerebral injury.In this paper,a locally mixed sub-low te...Nowadays,mild hypothermia is widely used in the fields of post-cardiac arrest resuscitation,stroke,cerebral hemorrhage,large-scale cerebral infarction,and craniocerebral injury.In this paper,a locally mixed sub-low temperature device is designed,and the cold and hot water mixing experiment is used to simulate the human blood transfer process.To set a foundation for the optimization of the heat transfer system,the static characteristics are analyzed by building the mathematic model and setting up the experimental station.In addition,the affection of several key structure parameters is researched.Through experimental and simulation studies,it can be concluded that,firstly,the mathematical model proved to be effective.Secondly,the results of simulation experiments show that 14.52℃ refrigeration can reduce the original temperature of 33.42℃ to 32.02℃,and the temperature of refrigerated blood rises to 18.64℃,and the average error is about 0.3℃.Thirdly,as the thermal conductivity of the vascular sheath increases,the efficiency of the heat exchange system also increases significantly.Finally,as the input cold blood flow rate increases,the mass increases and the temperature of the mixed blood temperature decreases.It provides a research basis for subsequent research on local fixed-point sub-low temperature control technology.展开更多
文摘This paper deals with an innovative low-loss AC switch, named as TBBS （transistor based bidirectional switch）, based on the association of super-gain BJTs developed by the GREMAN laboratory. The main characterization results of the super-gain BJT are reminded to identify the key parameters that are essential to build the TBBS. A complete characterization database in static mode of this new AC switch is discussed. In particular, its forward and reverse-biased features have been measured to see the evolution of the DC current gain as a function of the current density. The TBBS makes sense when using the super-gain BJT （bipolar junction transistor） in reverse mode. It means that the reverse DC current gain has to be sufficient （at least higher than l compared with the conventional BJT one）. This new AC switch is bidirectional in current and voltage, totally controllable （turn-on and turn-off） and the most attractive solution in terms of on-state power losses. Further, its manufacturing process is as easier as existing device such as triac.
基金Supported by the General Program of Natural Science Foundation of China(51874346).
文摘The Ordovician fracture-vug carbonate reservoirs of Tarim Basin,are featured by developed vugs,caves and fractures.The strong heterogeneity results in huge uncertainty when these reservoirs are quantitatively characterized using merely static seismic data.The effective quantitative characterization of the reservoirs has been an urgent problem to be solved.This study creatively proposes the"second quantitative characterization"technique with the combination of dynamic and static data based on the primary static quantitative characterization and fully considering lots of key influence factors when conducting characterization.In this technique,dynamic analysis methods such as well testing,production rate transient analysis,dynamic reserve evaluation and dynamic connectivity evaluation are used to get understandings on this kind of reservoir.These understandings are used as statistical parameters to constrain the inversion of seismic wave impedance to improve the relationship between wave impedance and porosity and determine the fracture-vug morphology,calculate dynamic reserves,and then a more accurate fracture-vugmodel can be selected and used to calculate the oil-water contact inversely based on the results of"second quantitative characterization".This method can lower the uncertainties in the primary quantitative characterization of fracture-vug reservoirs,enhance the accuracy of characterization results significantly,and has achieved good application results in the fracture-vug carbonate reservoirs of Tarim Basin.
基金Supported by Open Research Project of the State Key Laboratory of Media Convergence and Communication,Communication University of China(Grant No.SKLMCC2020KF002)Fundamental Research Funds for Central Public Welfare Research Institutes,National Key Research and Development Project(Grant No.2019YFC0121700)China Postdoctoral Science Foundation(Grant No.2019M660392).
文摘Nowadays,mild hypothermia is widely used in the fields of post-cardiac arrest resuscitation,stroke,cerebral hemorrhage,large-scale cerebral infarction,and craniocerebral injury.In this paper,a locally mixed sub-low temperature device is designed,and the cold and hot water mixing experiment is used to simulate the human blood transfer process.To set a foundation for the optimization of the heat transfer system,the static characteristics are analyzed by building the mathematic model and setting up the experimental station.In addition,the affection of several key structure parameters is researched.Through experimental and simulation studies,it can be concluded that,firstly,the mathematical model proved to be effective.Secondly,the results of simulation experiments show that 14.52℃ refrigeration can reduce the original temperature of 33.42℃ to 32.02℃,and the temperature of refrigerated blood rises to 18.64℃,and the average error is about 0.3℃.Thirdly,as the thermal conductivity of the vascular sheath increases,the efficiency of the heat exchange system also increases significantly.Finally,as the input cold blood flow rate increases,the mass increases and the temperature of the mixed blood temperature decreases.It provides a research basis for subsequent research on local fixed-point sub-low temperature control technology.
