A multi-gap and multi-channel gas switch with convexo-convex discal planet electrodes was designed and investigated. Eight gaps are formed in series by a trigger electrode, six intermediate electrodes and two high vol...A multi-gap and multi-channel gas switch with convexo-convex discal planet electrodes was designed and investigated. Eight gaps are formed in series by a trigger electrode, six intermediate electrodes and two high voltage electrodes with a uniform gap length of 5 ram. The self breakdown and triggered breakdown performance of the switch are reported. Both the delay time and jitter decrease with the increase in the trigger voltage, switching coefficient and the decrease in the trigger isolating resistor. The delay time of the switch is about 40 ns, and the jitter is less than 2 ns when charged with 4-85 kV and triggered by a voltage pule of -75 kV. The inductance of the switch is about 30 nH.展开更多
In order to realize the small error attitude transformation of a free floating space robot,a new method of three degrees of freedom（ DOF） attitude transformation was proposed for the space robot using a bionic joint...In order to realize the small error attitude transformation of a free floating space robot,a new method of three degrees of freedom（ DOF） attitude transformation was proposed for the space robot using a bionic joint. A general kinematic model of the space robot was established based on the law of linear and angular momentum conservation. A combinational joint model was established combined with bionic joint and closed motion. The attitude transformation of planar,two DOF and three DOF is analyzed and simulated by the model,and it is verified that the feasibility of attitude transformation in three DOF space. Finally,the specific scheme of disturbance elimination in attitude transformation is presented and simulation results are obtained.Therefore,the range of application field of the bionic joint model has been expanded.展开更多
To establish the algorithm of SAT-TMD system with the wavelet transform(WT),the modal mass participation ratio is proposed to distinguish if the high-rising structure has the characteristic of closely distributed freq...To establish the algorithm of SAT-TMD system with the wavelet transform(WT),the modal mass participation ratio is proposed to distinguish if the high-rising structure has the characteristic of closely distributed frequencies.A time varying analytical model of high-rising structure such as TV-tower with the SAT-TMD is developed.The proposed new idea is to use WT to identify the dominant frequency of structural response in a segment time,and track its variation as a function of time to retune the SAT-TMD.The effectiveness of SAT-TMD is investigated and it is more robust to change in building stiffness and damping than that of the TMD with a fixed frequency corresponding to a fixed mode frequency of the building.It is proved that SAT-TMD is particularly effective in reducing the response even when the building stiffness is changed by ±15%;whereas the TMD loses its effectiveness under such building stiffness variations.展开更多
Performance analysis during the early design stage can significantly reduce building energy consumption.However,it is difficult to transform computer-aided design(CAD)models into building energy models(BEM)to optimize...Performance analysis during the early design stage can significantly reduce building energy consumption.However,it is difficult to transform computer-aided design(CAD)models into building energy models(BEM)to optimize building performance.The model structures for CAD and BEM are divergent.In this study,geometry transformation methods was implemented in BES tools for the early design stage,including auto space generation(ASG)method based on closed contour recognition(CCR)and space boundary topology calculation method.The program is developed based on modeling tools SketchUp to support the CAD format(like*.stl,*.dwg,*.ifc,etc.).It transforms face-based geometric information into a zone-based tree structure model that meets the geometric requirements of a single-zone BES combined with the other thermal parameter inputs of the elements.In addition,this study provided a space topology calculation method based on a single-zone BEM output.The program was developed based on the SketchUp modeling tool to support additional CAD formats(such as*.stl,*.dwg,*.ifc),which can then be imported and transformed into*.obj.Compared to current methods mostly focused on BIM-BEM transformation,this method can ensure more modeling flexibility.The method was integrated into a performance analysis tool termed MOOSAS and compared with the current version of the transformation program.They were tested on a dataset comprising 36 conceptual models without partitions and six real cases with detailed partitions.It ensures a transformation rate of two times in any bad model condition and costs only 1/5 of the time required to calculate each room compared to the previous version.展开更多
聚变堆主机关键系统综合研究设施(Comprehensive Research Facility for Fusion Technology,CRAFT)负离子源中性束注入(Negative Neutral Beam Injection,NNBI)电源首次采用逆变型整流方案,但离子源的时变、非线性及高可控等负荷特征给...聚变堆主机关键系统综合研究设施(Comprehensive Research Facility for Fusion Technology,CRAFT)负离子源中性束注入(Negative Neutral Beam Injection,NNBI)电源首次采用逆变型整流方案,但离子源的时变、非线性及高可控等负荷特征给电源电压和纹波控制带来了挑战。采用傅里叶变换分析逆变型直流高压电源拓扑,针对低频开关信号,提出一种新的逆变型直流高压电源传递函数分析方法以快速建立系统近似模型。通过PWM方式控制逆变器开关管占空比,相控整流控制直流母线电压,实现系统输出电压闭环控制以及提升纹波抑制能力,并设计1200 V/5 A实验测试平台验证控制方法的有效性。展开更多
基金supported by National Natural Science Foundation of China(Nos.50477019,50637010)the State Key Laboratory of Electrical Insulation and Power Equipment of China(EIPE.09207)
文摘A multi-gap and multi-channel gas switch with convexo-convex discal planet electrodes was designed and investigated. Eight gaps are formed in series by a trigger electrode, six intermediate electrodes and two high voltage electrodes with a uniform gap length of 5 ram. The self breakdown and triggered breakdown performance of the switch are reported. Both the delay time and jitter decrease with the increase in the trigger voltage, switching coefficient and the decrease in the trigger isolating resistor. The delay time of the switch is about 40 ns, and the jitter is less than 2 ns when charged with 4-85 kV and triggered by a voltage pule of -75 kV. The inductance of the switch is about 30 nH.
文摘In order to realize the small error attitude transformation of a free floating space robot,a new method of three degrees of freedom（ DOF） attitude transformation was proposed for the space robot using a bionic joint. A general kinematic model of the space robot was established based on the law of linear and angular momentum conservation. A combinational joint model was established combined with bionic joint and closed motion. The attitude transformation of planar,two DOF and three DOF is analyzed and simulated by the model,and it is verified that the feasibility of attitude transformation in three DOF space. Finally,the specific scheme of disturbance elimination in attitude transformation is presented and simulation results are obtained.Therefore,the range of application field of the bionic joint model has been expanded.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50478031)China Postdoctoral Science Foundation(Grant No.2006040240)
文摘To establish the algorithm of SAT-TMD system with the wavelet transform(WT),the modal mass participation ratio is proposed to distinguish if the high-rising structure has the characteristic of closely distributed frequencies.A time varying analytical model of high-rising structure such as TV-tower with the SAT-TMD is developed.The proposed new idea is to use WT to identify the dominant frequency of structural response in a segment time,and track its variation as a function of time to retune the SAT-TMD.The effectiveness of SAT-TMD is investigated and it is more robust to change in building stiffness and damping than that of the TMD with a fixed frequency corresponding to a fixed mode frequency of the building.It is proved that SAT-TMD is particularly effective in reducing the response even when the building stiffness is changed by ±15%;whereas the TMD loses its effectiveness under such building stiffness variations.
基金We would like to thank the National Science Foundation of China(Grant No.52130803)for funding this study.
文摘Performance analysis during the early design stage can significantly reduce building energy consumption.However,it is difficult to transform computer-aided design(CAD)models into building energy models(BEM)to optimize building performance.The model structures for CAD and BEM are divergent.In this study,geometry transformation methods was implemented in BES tools for the early design stage,including auto space generation(ASG)method based on closed contour recognition(CCR)and space boundary topology calculation method.The program is developed based on modeling tools SketchUp to support the CAD format(like*.stl,*.dwg,*.ifc,etc.).It transforms face-based geometric information into a zone-based tree structure model that meets the geometric requirements of a single-zone BES combined with the other thermal parameter inputs of the elements.In addition,this study provided a space topology calculation method based on a single-zone BEM output.The program was developed based on the SketchUp modeling tool to support additional CAD formats(such as*.stl,*.dwg,*.ifc),which can then be imported and transformed into*.obj.Compared to current methods mostly focused on BIM-BEM transformation,this method can ensure more modeling flexibility.The method was integrated into a performance analysis tool termed MOOSAS and compared with the current version of the transformation program.They were tested on a dataset comprising 36 conceptual models without partitions and six real cases with detailed partitions.It ensures a transformation rate of two times in any bad model condition and costs only 1/5 of the time required to calculate each room compared to the previous version.
