高关水库1972年运行以来蓄满率低,防洪与兴利之间的矛盾突出。本文将高关水库的年最大洪水系列延长至2023年和考虑历史洪水调查资料,开展设计洪水复核计算,并与采用暴雨途径推求的成果进行对比分析。结果显示:由流量途径推求的设计洪水...高关水库1972年运行以来蓄满率低,防洪与兴利之间的矛盾突出。本文将高关水库的年最大洪水系列延长至2023年和考虑历史洪水调查资料,开展设计洪水复核计算,并与采用暴雨途径推求的成果进行对比分析。结果显示:由流量途径推求的设计洪水结果比由暴雨途径计算的结果明显偏小,百年一遇设计洪峰、12 h洪量和1 d洪量分别偏小15.92%、27.93%和23.58%,两千年一遇校核洪峰、12 h洪量和1 d洪量分别偏小12.21%、17.52%和13.56%;从安全和管理两方面综合考虑,建议年最大洪峰流量设计值采用暴雨途径计算的结果,而年最大洪量设计值采用流量途径计算的结果;采用同频率放大法推求设计洪水过程线,重新确定水库汛限水位,可提高水库的综合利用效益。The fill storage ratio of the Gaoguan Reservoir is very low since operation in 1972, and the contradiction between flood control and comprehensive utilization is prominent. In this study, extending the annual maximum (AM) flood data series to 2023 and considering the historical flood information, the design floods were rechecked and compared with those estimated by design storm. The result shows that the 100-year design flood (2000-year check flood) peak discharge, 12 h and 1 d flood volume estimated by the flow discharge series are 15.92% (12.21%), 27.93% (17.52%), and 23.58% (13.56%) smaller than those calculated by the rain storm data, respectively;Comprehensively considering the safety and management factors, it is suggested that the design discharge peak and flood volume are selected based on AM rain storm and flood data series, respectively. The same frequency amplify method was used to derive design flood hydrograph, so as to determine the reservoir’s flood limited water level which will improve the comprehensive utilization benefit of the reservoir.展开更多
GaAs PIN diodes optimized for X-band low loss and high isolation switch application are presented. The impact of diode physical characteristics and electrical parameters on switch performance is discussed. A new struc...GaAs PIN diodes optimized for X-band low loss and high isolation switch application are presented. The impact of diode physical characteristics and electrical parameters on switch performance is discussed. A new structure for GaAs PIN diodes is proposed and the fabrication process is described. GaAs PIN diodes with an on-state resistance of 〈2. 2Ω and off-state capacitance -〈20fF in the range of 100MHz to 12.1GHz are obtained.展开更多
Both the repeated triaxial test （RTT） and the Hamburg wheel tracking test （HWTT） are adopted to evaluate the high temperature performance of the stone mastic asphalt （SMA） and the mastic asphalt （MA）. The corr...Both the repeated triaxial test （RTT） and the Hamburg wheel tracking test （HWTT） are adopted to evaluate the high temperature performance of the stone mastic asphalt （SMA） and the mastic asphalt （MA）. The correlation of the permanent deformations of the MA and the correlation of the deformation developments of the SMA between the two tests are analyzed, respectively. Results show that both the two tests can effectively identify the high temperature performance of mixtures, and the correlation between the final results of the two tests as well as that between the deformation developments of the two tests are excellent with R20.9. In order to further prove the correlation, viscoelastic parameters estimated from the RTT results is used to simulate the rutting development in the HWTT slabs by the finite element method （FEM）. Results indicate that the correlation between the two tests is significant with errors less than 10%. It is suitable to predict the rutting development with the viscoelastic parameters obtained from the RTT.展开更多
A model for theoretical analysis of nonlinear (or high gain) mode of photoconductive semiconductor switches (PCSS's) is proposed.The switching transition of high gain PCSS's can be described with an optically...A model for theoretical analysis of nonlinear (or high gain) mode of photoconductive semiconductor switches (PCSS's) is proposed.The switching transition of high gain PCSS's can be described with an optically activated charge domain. The switching characteristics including rise time,delay and their relationship to electric field strength,optical trigger energies are discussed.The formation and radiation transit,accumulation of the charge domain are related with the triggering and sustaining phases of PCSS's,respectively.The results of the mathematical model on this mechanism agree with experimental results.展开更多
High-speed on-off valves are widey used in PWM electropneumatic servo sys- tems and their characteristics are generally described by their on and off delay time. This paper focuses on establishing the relationships be...High-speed on-off valves are widey used in PWM electropneumatic servo sys- tems and their characteristics are generally described by their on and off delay time. This paper focuses on establishing the relationships between their on-off switching behaviors and their frequency response characteristics. A method is proposed by which the frequency response characteristics of an analog PWM high-speed on-off valve can be calculated for inputs whose periods are certain multiples of the carrier period, based on its switching be- haviors. Thus, a simple and direct describing function for a PWM high-speed on-off valve is established.展开更多
文摘高关水库1972年运行以来蓄满率低,防洪与兴利之间的矛盾突出。本文将高关水库的年最大洪水系列延长至2023年和考虑历史洪水调查资料,开展设计洪水复核计算,并与采用暴雨途径推求的成果进行对比分析。结果显示:由流量途径推求的设计洪水结果比由暴雨途径计算的结果明显偏小,百年一遇设计洪峰、12 h洪量和1 d洪量分别偏小15.92%、27.93%和23.58%,两千年一遇校核洪峰、12 h洪量和1 d洪量分别偏小12.21%、17.52%和13.56%;从安全和管理两方面综合考虑,建议年最大洪峰流量设计值采用暴雨途径计算的结果,而年最大洪量设计值采用流量途径计算的结果;采用同频率放大法推求设计洪水过程线,重新确定水库汛限水位,可提高水库的综合利用效益。The fill storage ratio of the Gaoguan Reservoir is very low since operation in 1972, and the contradiction between flood control and comprehensive utilization is prominent. In this study, extending the annual maximum (AM) flood data series to 2023 and considering the historical flood information, the design floods were rechecked and compared with those estimated by design storm. The result shows that the 100-year design flood (2000-year check flood) peak discharge, 12 h and 1 d flood volume estimated by the flow discharge series are 15.92% (12.21%), 27.93% (17.52%), and 23.58% (13.56%) smaller than those calculated by the rain storm data, respectively;Comprehensively considering the safety and management factors, it is suggested that the design discharge peak and flood volume are selected based on AM rain storm and flood data series, respectively. The same frequency amplify method was used to derive design flood hydrograph, so as to determine the reservoir’s flood limited water level which will improve the comprehensive utilization benefit of the reservoir.
文摘GaAs PIN diodes optimized for X-band low loss and high isolation switch application are presented. The impact of diode physical characteristics and electrical parameters on switch performance is discussed. A new structure for GaAs PIN diodes is proposed and the fabrication process is described. GaAs PIN diodes with an on-state resistance of 〈2. 2Ω and off-state capacitance -〈20fF in the range of 100MHz to 12.1GHz are obtained.
基金The Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry (No.6821001005)
文摘Both the repeated triaxial test （RTT） and the Hamburg wheel tracking test （HWTT） are adopted to evaluate the high temperature performance of the stone mastic asphalt （SMA） and the mastic asphalt （MA）. The correlation of the permanent deformations of the MA and the correlation of the deformation developments of the SMA between the two tests are analyzed, respectively. Results show that both the two tests can effectively identify the high temperature performance of mixtures, and the correlation between the final results of the two tests as well as that between the deformation developments of the two tests are excellent with R20.9. In order to further prove the correlation, viscoelastic parameters estimated from the RTT results is used to simulate the rutting development in the HWTT slabs by the finite element method （FEM）. Results indicate that the correlation between the two tests is significant with errors less than 10%. It is suitable to predict the rutting development with the viscoelastic parameters obtained from the RTT.
文摘A model for theoretical analysis of nonlinear (or high gain) mode of photoconductive semiconductor switches (PCSS's) is proposed.The switching transition of high gain PCSS's can be described with an optically activated charge domain. The switching characteristics including rise time,delay and their relationship to electric field strength,optical trigger energies are discussed.The formation and radiation transit,accumulation of the charge domain are related with the triggering and sustaining phases of PCSS's,respectively.The results of the mathematical model on this mechanism agree with experimental results.
文摘High-speed on-off valves are widey used in PWM electropneumatic servo sys- tems and their characteristics are generally described by their on and off delay time. This paper focuses on establishing the relationships between their on-off switching behaviors and their frequency response characteristics. A method is proposed by which the frequency response characteristics of an analog PWM high-speed on-off valve can be calculated for inputs whose periods are certain multiples of the carrier period, based on its switching be- haviors. Thus, a simple and direct describing function for a PWM high-speed on-off valve is established.
