We propose a lumped element Josephson parametric amplifier with vacuum-gap-based capacitor.The capacitor is made of quasi-floating aluminum pad and on-chip ground.We take a fabrication process compatible with air-brid...We propose a lumped element Josephson parametric amplifier with vacuum-gap-based capacitor.The capacitor is made of quasi-floating aluminum pad and on-chip ground.We take a fabrication process compatible with air-bridge technology,which makes our design adaptable for future on-chip integrated quantum computing system.Further engineering the input impedance,we obtain a gain above 20 dB over 162-MHz bandwidth,along with a quasi quantum-limit noise performance.This work should facilitate the development of quantum information processing and integrated superconducting circuit design.展开更多
Experimental study of the long-gap distance vacuum arc distortion for three types of axial magnetic field （AMF） contacts, by using high-speed charge coupled device （CCD）, is presented. The arc current was of a hal...Experimental study of the long-gap distance vacuum arc distortion for three types of axial magnetic field （AMF） contacts, by using high-speed charge coupled device （CCD）, is presented. The arc current was of a half-cycle sine wave with a frequency of 50 Hz, produced by an L=C discharging circuit. The time of appearance and duration of vacuum arc distortion under three conditions were studied. It was found that the gap distance, current and diameter of the electrode affected the characteristics of vacuum distortion at a long-gap distance. Some characteristics of the vacuum arc at a long-gap distance were revealed and the experience and data for further investigation were provided.展开更多
The greenhouse effect of SFe is a great concern today. The development of high voltage vacuum circuit breakers becomes more important. The vacuum circuit breaker has minimum pollution to the environment. The vacuum in...The greenhouse effect of SFe is a great concern today. The development of high voltage vacuum circuit breakers becomes more important. The vacuum circuit breaker has minimum pollution to the environment. The vacuum interrupter is the key part of a vacuum circuit breaker. The interrupting characteristics in vacuum and arc-controlling techniue are the main problems to be solved for a longer gap distance in developing high voltage vacuum interrupters. To understand the vacuum arc characteristics and provide effective technique to control vacuum arc in a long gap distance, the arc mode transition of a cup-type axial magnetic field electrode is observed by a high-speed charge coupled device （CGD） video camera under different gap distances while the arc voltage and arc current are recorded. The controlling ability of the axial magnetic field on vacuum arc obviously decreases when the gap distance is longer than 40 ram. The noise components and mean value of the arc voltage significantly increase. The effective method for controlling the vacuum arc characteristics is provided by long gap distances based on the test results. The test results can be used as a reference to develop high voltage and large capacity vacuum interrupters.展开更多
Ⅰ. INTRODUCTION The vacuum is used extensively for the insulation of high voltages. It is expected to understand the process of vacuum breakdown, so as to improve the insulation qualities of the vacuum gap and preven...Ⅰ. INTRODUCTION The vacuum is used extensively for the insulation of high voltages. It is expected to understand the process of vacuum breakdown, so as to improve the insulation qualities of the vacuum gap and prevent the unexpected accident. So far, there are several models, such as field electron emission model, microparticle model, to explain the processes of breakdown in the vacuum gap. These models have explained展开更多
The influence of an arc current on the discharge development and the arc modes of a single coil type axial magnetic field （AMF） electrode were investigated by a high-speed charge couple device （CCD） video camera i...The influence of an arc current on the discharge development and the arc modes of a single coil type axial magnetic field （AMF） electrode were investigated by a high-speed charge couple device （CCD） video camera in a long gap distance of 40 mm. The distribution of the axial magnetic field of the single coil type AMF electrode was computed. By computational results, the single coil type AMF electrode could generate higher axial magnetic flux density than the slot type AMF electrode. It was found that the single coil type AMF electrode could perform better than the slot type AMF electrode with the same designing parameters. And the development of the arc modes experienced diffuse mode, constricted but unstable mode, and constricted and stable mode with the amplitude of the arc current increasing. The correlation between the vacuum arc and the noise components of arc voltage was investigated too. The interruption capability could be known in a practical commercial vacuum interrupter by the test results in a demountable vacuum interrupter （DVC） with a electrode diameter of 50 mm and a gap distance of 40 mm.The test results could provide reference to design the high voltage vacuum interrupter adopting the single coil type AMF electrode.展开更多
To improve the performance of a metal ion plasma jet in vacuum discharge, an anode-insulated cone-cylinder electrode with insulating sleeve is proposed in this paper. Discharge characteristics and generation character...To improve the performance of a metal ion plasma jet in vacuum discharge, an anode-insulated cone-cylinder electrode with insulating sleeve is proposed in this paper. Discharge characteristics and generation characteristics of plasma of the electrode are investigated, effects of diameter of insulating sleeve, variety of cathode material and length of the insulating sleeve on characteristics of metal ion plasma jet are discussed. Results indicate that a directional and steady plasma jet is formed by using the novel electrode with insulating sleeve under high vacuum conditions. Moreover, the properties of metal ion plasma jet are improved by using the aluminum cathode and thin and long insulating sleeve. The study provides strong support for research of vacuum metal ion plasma thruster and ion implantation technology.展开更多
When subjected to high voltages between opened contacts, vacuum interrupters may emit X-rays. In order to ensure that these are of an acceptable level, vacuum interrupters should comply with the limits for X-ray emiss...When subjected to high voltages between opened contacts, vacuum interrupters may emit X-rays. In order to ensure that these are of an acceptable level, vacuum interrupters should comply with the limits for X-ray emission and the test procedures to be carried out to verify this based on relevant standards and specifications. In this paper, a comprehensive experimental study has been performed for 126 kV vacuum interrupters used in a transmission system to understand the X-radiation level and its influence by three main parameters, namely applied power-frequency voltage, contact gap and power=frequency voltage conditioning. The radiation instrument is an FJ347 radiometer and the X-radiation dose was measured at the power-frequency test voltage. These tests demonstrated that the X-radiation emission level for a 126 kV vacuum interrupter did not exceed the following： 5 μSv per hour at a rated voltage of 126 kV and 150 μSv per hour at a power-frequency voltage of 230 kV at 1 m distance. The X-radiation dose increased with the applied power-frequency voltage increasing and decreased with the contact gap increasing. The X- radiation dose for 126 kV vacuum interrupters decreased by 57% after the conditioning procedure with a certain power-frequency voltage. During the conditioning procedure, the average value of the X-radiation dose was 4.49 mSv, which means if a professional conditions 180 interrupters per year, it will be safe at the 6.4 m distance.展开更多
为提升采用CO2气体作为灭弧介质的高压断路器大电流开断能力,对真空间隙与CO2气体间隙串联开断过程进行研究。通过建立12 k V真空间隙与72.5 k V CO2气体间隙组成的串联间隙电弧黑盒模型,分析两间隙承担暂态恢复电压起始时刻不同时两间...为提升采用CO2气体作为灭弧介质的高压断路器大电流开断能力,对真空间隙与CO2气体间隙串联开断过程进行研究。通过建立12 k V真空间隙与72.5 k V CO2气体间隙组成的串联间隙电弧黑盒模型,分析两间隙承担暂态恢复电压起始时刻不同时两间隙协同作用关系;研究两间隙并联分压电容对间隙间电压分布特性的影响;对比串联间隙与单一气体间隙开断性能的差异。仿真结果表明：真空间隙先承担恢复电压有利于CO2气体间隙介质强度快速恢复,真空间隙提前15～30μs承担恢复电压时串联间隙表现出较好的协同开断效果;两间隙在不同时刻承担恢复电压时设置合适的分压电容可优化间隙间的恢复电压分布特性。CO2气体间隙串联真空间隙后可提升其大电流开断能力,为环保型高压断路器设计提供可借鉴方法。展开更多
基金the National Key Research and Development Program of China(Grant No.2016YFA0301200)the National Natural Science Foundation of China(Grant Nos.62074091,12004044,and U1930402)+2 种基金the Science Challenge Project(Grant No.TZ2018003)the Fund from the New Energy and Industrial Technology Development Organization(Grant No.JPNP16007)Japan Science and Technology Agency(Moonshot R&D,Grant No.JPMJMS2067 and CREST,Grant No.JPMJCR1676).
文摘We propose a lumped element Josephson parametric amplifier with vacuum-gap-based capacitor.The capacitor is made of quasi-floating aluminum pad and on-chip ground.We take a fabrication process compatible with air-bridge technology,which makes our design adaptable for future on-chip integrated quantum computing system.Further engineering the input impedance,we obtain a gain above 20 dB over 162-MHz bandwidth,along with a quasi quantum-limit noise performance.This work should facilitate the development of quantum information processing and integrated superconducting circuit design.
基金supported by National Natural Science Foundation of China (No.50477024)
文摘Experimental study of the long-gap distance vacuum arc distortion for three types of axial magnetic field （AMF） contacts, by using high-speed charge coupled device （CCD）, is presented. The arc current was of a half-cycle sine wave with a frequency of 50 Hz, produced by an L=C discharging circuit. The time of appearance and duration of vacuum arc distortion under three conditions were studied. It was found that the gap distance, current and diameter of the electrode affected the characteristics of vacuum distortion at a long-gap distance. Some characteristics of the vacuum arc at a long-gap distance were revealed and the experience and data for further investigation were provided.
基金supported by National Natural Science Foundation of China(No.50477024)
文摘The greenhouse effect of SFe is a great concern today. The development of high voltage vacuum circuit breakers becomes more important. The vacuum circuit breaker has minimum pollution to the environment. The vacuum interrupter is the key part of a vacuum circuit breaker. The interrupting characteristics in vacuum and arc-controlling techniue are the main problems to be solved for a longer gap distance in developing high voltage vacuum interrupters. To understand the vacuum arc characteristics and provide effective technique to control vacuum arc in a long gap distance, the arc mode transition of a cup-type axial magnetic field electrode is observed by a high-speed charge coupled device （CGD） video camera under different gap distances while the arc voltage and arc current are recorded. The controlling ability of the axial magnetic field on vacuum arc obviously decreases when the gap distance is longer than 40 ram. The noise components and mean value of the arc voltage significantly increase. The effective method for controlling the vacuum arc characteristics is provided by long gap distances based on the test results. The test results can be used as a reference to develop high voltage and large capacity vacuum interrupters.
基金Project supported by the National Natural Science Foundation of China
文摘Ⅰ. INTRODUCTION The vacuum is used extensively for the insulation of high voltages. It is expected to understand the process of vacuum breakdown, so as to improve the insulation qualities of the vacuum gap and prevent the unexpected accident. So far, there are several models, such as field electron emission model, microparticle model, to explain the processes of breakdown in the vacuum gap. These models have explained
基金National Nature Science Foundation of China(No.50477024)
文摘The influence of an arc current on the discharge development and the arc modes of a single coil type axial magnetic field （AMF） electrode were investigated by a high-speed charge couple device （CCD） video camera in a long gap distance of 40 mm. The distribution of the axial magnetic field of the single coil type AMF electrode was computed. By computational results, the single coil type AMF electrode could generate higher axial magnetic flux density than the slot type AMF electrode. It was found that the single coil type AMF electrode could perform better than the slot type AMF electrode with the same designing parameters. And the development of the arc modes experienced diffuse mode, constricted but unstable mode, and constricted and stable mode with the amplitude of the arc current increasing. The correlation between the vacuum arc and the noise components of arc voltage was investigated too. The interruption capability could be known in a practical commercial vacuum interrupter by the test results in a demountable vacuum interrupter （DVC） with a electrode diameter of 50 mm and a gap distance of 40 mm.The test results could provide reference to design the high voltage vacuum interrupter adopting the single coil type AMF electrode.
基金supported by National Natural Science Foundation of China(No.51577011)
文摘To improve the performance of a metal ion plasma jet in vacuum discharge, an anode-insulated cone-cylinder electrode with insulating sleeve is proposed in this paper. Discharge characteristics and generation characteristics of plasma of the electrode are investigated, effects of diameter of insulating sleeve, variety of cathode material and length of the insulating sleeve on characteristics of metal ion plasma jet are discussed. Results indicate that a directional and steady plasma jet is formed by using the novel electrode with insulating sleeve under high vacuum conditions. Moreover, the properties of metal ion plasma jet are improved by using the aluminum cathode and thin and long insulating sleeve. The study provides strong support for research of vacuum metal ion plasma thruster and ion implantation technology.
基金supported by National Key Basic Research Program of China(973 Program)(No.2015CB251002)
文摘When subjected to high voltages between opened contacts, vacuum interrupters may emit X-rays. In order to ensure that these are of an acceptable level, vacuum interrupters should comply with the limits for X-ray emission and the test procedures to be carried out to verify this based on relevant standards and specifications. In this paper, a comprehensive experimental study has been performed for 126 kV vacuum interrupters used in a transmission system to understand the X-radiation level and its influence by three main parameters, namely applied power-frequency voltage, contact gap and power=frequency voltage conditioning. The radiation instrument is an FJ347 radiometer and the X-radiation dose was measured at the power-frequency test voltage. These tests demonstrated that the X-radiation emission level for a 126 kV vacuum interrupter did not exceed the following： 5 μSv per hour at a rated voltage of 126 kV and 150 μSv per hour at a power-frequency voltage of 230 kV at 1 m distance. The X-radiation dose increased with the applied power-frequency voltage increasing and decreased with the contact gap increasing. The X- radiation dose for 126 kV vacuum interrupters decreased by 57% after the conditioning procedure with a certain power-frequency voltage. During the conditioning procedure, the average value of the X-radiation dose was 4.49 mSv, which means if a professional conditions 180 interrupters per year, it will be safe at the 6.4 m distance.
文摘为提升采用CO2气体作为灭弧介质的高压断路器大电流开断能力,对真空间隙与CO2气体间隙串联开断过程进行研究。通过建立12 k V真空间隙与72.5 k V CO2气体间隙组成的串联间隙电弧黑盒模型,分析两间隙承担暂态恢复电压起始时刻不同时两间隙协同作用关系;研究两间隙并联分压电容对间隙间电压分布特性的影响;对比串联间隙与单一气体间隙开断性能的差异。仿真结果表明：真空间隙先承担恢复电压有利于CO2气体间隙介质强度快速恢复,真空间隙提前15～30μs承担恢复电压时串联间隙表现出较好的协同开断效果;两间隙在不同时刻承担恢复电压时设置合适的分压电容可优化间隙间的恢复电压分布特性。CO2气体间隙串联真空间隙后可提升其大电流开断能力,为环保型高压断路器设计提供可借鉴方法。
