In this study, the changes of a vacuum arc＇s appearance were observed and the volt-ampere characteristics of the vacuum arc at intermediate frequency were analyzed under a transverse magnetic field （TMF）. The TMF a...In this study, the changes of a vacuum arc＇s appearance were observed and the volt-ampere characteristics of the vacuum arc at intermediate frequency were analyzed under a transverse magnetic field （TMF）. The TMF and phase shift time were calculated by using the TMF contact model and the large phase shift of the magnetic field at a higher frequency was conductive to the dispersion process of residual plasma. The arc velocity was higher at 800 Hz than at 400 Hz. It can be inferred that TMF will encourage arc movement at 800 Hz. Moreover, the arc movement has an impact on the arc voltage. Because of the increasing length of the arc column with a high arc velocity, the elongated arc causes the arc voltage to increase. Specifically, the volt-ampere characteristics of the vacuum arc are divided into three stages in this paper. The higher the frequency, the greater the initial rate of rise in the arc voltage and the larger the area surrounded by arc volt-ampere characteristics. The correlations between the arc voltage and the amplitude and frequency of the current are also presented.展开更多
Thermal steam plasma jet is promising for applications in environmental industries due to its distinctive characteristics of high enthalpy and high chemical reactivity. However, the performance of the steam plasma tor...Thermal steam plasma jet is promising for applications in environmental industries due to its distinctive characteristics of high enthalpy and high chemical reactivity. However, the performance of the steam plasma torch for its generation is limited by the problems of the large arc voltage fluctuation and serious erosion of the electrodes. In this study, a gas-stabilized steam plasma torch which can operate continuously and stably was designed. Experiments were conducted to reveal the effect of the different working parameters, including the anode diameter, the cooling water temperature, the arc current and the steam flow rate, on its Volt-Ampere characteristics, arc voltage fluctuation, thermal efficiency, jet characteristics and electrodes erosion. Results showed that the use of hot water to cool the electrodes can effectively prevent the condensation of steam on the inner wall of the electrodes, thus significantly reducing the arc voltage fluctuations and electrodes erosion. This is crucial for increasing the working life of the electrodes and ensuring long-term stability of the steam plasma torch. In addition, suitable anode diameter can greatly reduce the arc voltage fluctuation of the steam plasma torch and effectively improve the stability of the steam plasma jet. Furthermore, high arc current can effectively reduce the fluctuations of the arc voltage and increase the length and the volume of the steam plasma jet. Finally, using steam as the plasma forming gas can achieve higher thermal efficiency compared to air. An ideal thermal efficiency can be achieved by properly reducing the arc current and increasing the steam flow rate.展开更多
Based on the principle of ion-bombarded reemission and sputtering desorption, the Glow Discharge Cleaning with helium (GDC(He)) is an effective method for controlling the recycle of H on the chamber wall, Carbon(C), O...Based on the principle of ion-bombarded reemission and sputtering desorption, the Glow Discharge Cleaning with helium (GDC(He)) is an effective method for controlling the recycle of H on the chamber wall, Carbon(C), Oxygen(O) impurity and improving the wall conditioning in HL-lM tokamak. It is characterized by simplicity without magnet and safety, compared with Taylor Discharge Cleaning (TDC), Alternating current glow discharge Cleaning (AC), Electron Cyclotron Resonance-Discharge Cleaning (ECR-DC). Compared with bake-out degassing, the wall has a higher degassing rate during GDC(He) and a lower impurity concentration in vacuum chambers after GDC(He). Cleaning patterns have been developed dominantly for de-oxidization, de-carbonization and de-hydrogenization. The cleaning parameters for H recycle on the wall are also presented. This paper mainly describes the GDC system along with its parameters, breakdown voltage, volt-ampere characteristic, the range of operation safe and suitable cleaning patterns in the HL-lM tokamak, finally concluding with some suggestions on HL-2A GDC.展开更多
In order to study the methods to enhance the efficacy of electrodeless lamp,volt-ampere characteristics,illuminance and emission spectrum have been investigated in home-built electrodeless lamp experimental system wit...In order to study the methods to enhance the efficacy of electrodeless lamp,volt-ampere characteristics,illuminance and emission spectrum have been investigated in home-built electrodeless lamp experimental system with an electrodeless lamp in shape like QL 85 lamp.The results show that lamp current increases as lamp voltage increases in non-discharge,the current decreases first and then increases as the voltage increases in discharge.The illuminance of electrodeless lamp increases linearly with discharge power increasing,and it decreases linearly with power decreasing.The emission spectrum is different for different bulb and lighting time.The spectrum of Ar 811.5 nm,76.5 nm,750.4 nm and Hg 313.2 nm decrease with lighting time.While the intensity of Hg 407.8 nm increases with lighting time.展开更多
The volt-ampere (Ⅰ-Ⅴ) characteristics of the c/s-poly (phenyl acetylene) (PPA) of cis-transoidal structure has been studied in the temperature range of 253-288K. An ITO/ PPA/ Au sandwich configuration was used for t...The volt-ampere (Ⅰ-Ⅴ) characteristics of the c/s-poly (phenyl acetylene) (PPA) of cis-transoidal structure has been studied in the temperature range of 253-288K. An ITO/ PPA/ Au sandwich configuration was used for the measurements. Under an applied field of less than 10~5V/ cm it showed ohmic behavior, while the space charge limited current (SCLC) was observed at applied fields above 5×10~5V/ cm. In the ohmic region a conductivity of 1.37×10^(-16)S/ cm was obtained at room temperature with an activation energy of 0.5eV. These data indicate that the conduction is not intrinsic one but is the result of thermal release of trapped carriers. In fact the data in the SCLC region treated according to the theory for a single Gaussian distribution of traps gave a mean trap energy of 0.48 eV with a half-width of 0.4 eV and a total density of trapping states of 5×10^(16)/cm^3.展开更多
The characteristics of a nitrogen arc using a graphite cathode and a melting anode in a pilot-scale plasma furnace are investigated. The voltage is examined as a function of current and apparent plasma length. The vol...The characteristics of a nitrogen arc using a graphite cathode and a melting anode in a pilot-scale plasma furnace are investigated. The voltage is examined as a function of current and apparent plasma length. The voltage increases non-linearly with the increase of apparent plasma length, with the current fixed. The experimental data so obtained are compared with the predictions of the Bowman model for the electric arc, and with numerical simulations as well. The level of agreement between the experimental data at the melting anode and the numerical predictions confirms the suitability of the proposed the Bowman model. These characteristics are relevant to the engineering design and evaluation of a DC plasma furnace and reactor for the treatment of hazardous fly ash waste.展开更多
Current dependence and stability of the measured resistance value are very important for the accurate measurement of DC standard resistor. In this paper, the volt-ampere （V-I） measurement method has been applied ...Current dependence and stability of the measured resistance value are very important for the accurate measurement of DC standard resistor. In this paper, the volt-ampere （V-I） measurement method has been applied to study the current depend-ence of four different types of standard resistors. Diverse values are obtained through the investigation of their stability at dif-ferent currents. Therefore, the current dependence coefficient （CDC） can be determined for each one of the studied resistors. Research shows CDC depends on the applied current value, the measurement time and the resistor type, as clearly demonstra-ted in this research.展开更多
从现有波动量法出发,研究用户波动与背景谐波变化对公共联结点谐波电流、谐波电压的影响,提出一种基于用户主导波动量筛选原理的用户谐波发射水平估计方法。提出公共连接点(point of common coupling,PCC)谐波波动伏安特性比的概念,研...从现有波动量法出发,研究用户波动与背景谐波变化对公共联结点谐波电流、谐波电压的影响,提出一种基于用户主导波动量筛选原理的用户谐波发射水平估计方法。提出公共连接点(point of common coupling,PCC)谐波波动伏安特性比的概念,研究系统侧、用户侧谐波波动对其变化的影响;利用统计学筛选方法从PCC点谐波电流测量值中筛选出用户主导谐波电流波动量,以此估计系统谐波阻抗;采用用户谐波电压发射水平修正公式消除背景谐波的影响。对理论模型和实际工程算例的仿真证明该文方法的正确性和有效性。展开更多
基金supported by Special Scientific and Research Funds for Doctoral Specialty of Institution of Higher Learning (200800060004)National Natural Science Foundation of China (No. 51177004)by the Innovation foundation of BUAA for Ph.D Graduates
文摘In this study, the changes of a vacuum arc＇s appearance were observed and the volt-ampere characteristics of the vacuum arc at intermediate frequency were analyzed under a transverse magnetic field （TMF）. The TMF and phase shift time were calculated by using the TMF contact model and the large phase shift of the magnetic field at a higher frequency was conductive to the dispersion process of residual plasma. The arc velocity was higher at 800 Hz than at 400 Hz. It can be inferred that TMF will encourage arc movement at 800 Hz. Moreover, the arc movement has an impact on the arc voltage. Because of the increasing length of the arc column with a high arc velocity, the elongated arc causes the arc voltage to increase. Specifically, the volt-ampere characteristics of the vacuum arc are divided into three stages in this paper. The higher the frequency, the greater the initial rate of rise in the arc voltage and the larger the area surrounded by arc volt-ampere characteristics. The correlations between the arc voltage and the amplitude and frequency of the current are also presented.
基金the support of the Key Research Program of the Sichuan Provincial Science and Technology Department,China(No.2017GZ0096)
文摘Thermal steam plasma jet is promising for applications in environmental industries due to its distinctive characteristics of high enthalpy and high chemical reactivity. However, the performance of the steam plasma torch for its generation is limited by the problems of the large arc voltage fluctuation and serious erosion of the electrodes. In this study, a gas-stabilized steam plasma torch which can operate continuously and stably was designed. Experiments were conducted to reveal the effect of the different working parameters, including the anode diameter, the cooling water temperature, the arc current and the steam flow rate, on its Volt-Ampere characteristics, arc voltage fluctuation, thermal efficiency, jet characteristics and electrodes erosion. Results showed that the use of hot water to cool the electrodes can effectively prevent the condensation of steam on the inner wall of the electrodes, thus significantly reducing the arc voltage fluctuations and electrodes erosion. This is crucial for increasing the working life of the electrodes and ensuring long-term stability of the steam plasma torch. In addition, suitable anode diameter can greatly reduce the arc voltage fluctuation of the steam plasma torch and effectively improve the stability of the steam plasma jet. Furthermore, high arc current can effectively reduce the fluctuations of the arc voltage and increase the length and the volume of the steam plasma jet. Finally, using steam as the plasma forming gas can achieve higher thermal efficiency compared to air. An ideal thermal efficiency can be achieved by properly reducing the arc current and increasing the steam flow rate.
文摘Based on the principle of ion-bombarded reemission and sputtering desorption, the Glow Discharge Cleaning with helium (GDC(He)) is an effective method for controlling the recycle of H on the chamber wall, Carbon(C), Oxygen(O) impurity and improving the wall conditioning in HL-lM tokamak. It is characterized by simplicity without magnet and safety, compared with Taylor Discharge Cleaning (TDC), Alternating current glow discharge Cleaning (AC), Electron Cyclotron Resonance-Discharge Cleaning (ECR-DC). Compared with bake-out degassing, the wall has a higher degassing rate during GDC(He) and a lower impurity concentration in vacuum chambers after GDC(He). Cleaning patterns have been developed dominantly for de-oxidization, de-carbonization and de-hydrogenization. The cleaning parameters for H recycle on the wall are also presented. This paper mainly describes the GDC system along with its parameters, breakdown voltage, volt-ampere characteristic, the range of operation safe and suitable cleaning patterns in the HL-lM tokamak, finally concluding with some suggestions on HL-2A GDC.
基金Project Supported by National Natural Science Foundation of China(50477005)China Postdoctoral Science Foundation (20100480255)Basic Research Foundation of Tsinghua University(JCpy2005053,20092000399,20102000442)
文摘In order to study the methods to enhance the efficacy of electrodeless lamp,volt-ampere characteristics,illuminance and emission spectrum have been investigated in home-built electrodeless lamp experimental system with an electrodeless lamp in shape like QL 85 lamp.The results show that lamp current increases as lamp voltage increases in non-discharge,the current decreases first and then increases as the voltage increases in discharge.The illuminance of electrodeless lamp increases linearly with discharge power increasing,and it decreases linearly with power decreasing.The emission spectrum is different for different bulb and lighting time.The spectrum of Ar 811.5 nm,76.5 nm,750.4 nm and Hg 313.2 nm decrease with lighting time.While the intensity of Hg 407.8 nm increases with lighting time.
文摘The volt-ampere (Ⅰ-Ⅴ) characteristics of the c/s-poly (phenyl acetylene) (PPA) of cis-transoidal structure has been studied in the temperature range of 253-288K. An ITO/ PPA/ Au sandwich configuration was used for the measurements. Under an applied field of less than 10~5V/ cm it showed ohmic behavior, while the space charge limited current (SCLC) was observed at applied fields above 5×10~5V/ cm. In the ohmic region a conductivity of 1.37×10^(-16)S/ cm was obtained at room temperature with an activation energy of 0.5eV. These data indicate that the conduction is not intrinsic one but is the result of thermal release of trapped carriers. In fact the data in the SCLC region treated according to the theory for a single Gaussian distribution of traps gave a mean trap energy of 0.48 eV with a half-width of 0.4 eV and a total density of trapping states of 5×10^(16)/cm^3.
基金supported by the National Natural Science Foundation of China (Grant No. 21171169)the Knowledge Innovation Project of the Chinese Academy of Sciences (Grant No. O45CF3A211)
文摘The characteristics of a nitrogen arc using a graphite cathode and a melting anode in a pilot-scale plasma furnace are investigated. The voltage is examined as a function of current and apparent plasma length. The voltage increases non-linearly with the increase of apparent plasma length, with the current fixed. The experimental data so obtained are compared with the predictions of the Bowman model for the electric arc, and with numerical simulations as well. The level of agreement between the experimental data at the melting anode and the numerical predictions confirms the suitability of the proposed the Bowman model. These characteristics are relevant to the engineering design and evaluation of a DC plasma furnace and reactor for the treatment of hazardous fly ash waste.
文摘Current dependence and stability of the measured resistance value are very important for the accurate measurement of DC standard resistor. In this paper, the volt-ampere （V-I） measurement method has been applied to study the current depend-ence of four different types of standard resistors. Diverse values are obtained through the investigation of their stability at dif-ferent currents. Therefore, the current dependence coefficient （CDC） can be determined for each one of the studied resistors. Research shows CDC depends on the applied current value, the measurement time and the resistor type, as clearly demonstra-ted in this research.
文摘从现有波动量法出发,研究用户波动与背景谐波变化对公共联结点谐波电流、谐波电压的影响,提出一种基于用户主导波动量筛选原理的用户谐波发射水平估计方法。提出公共连接点(point of common coupling,PCC)谐波波动伏安特性比的概念,研究系统侧、用户侧谐波波动对其变化的影响;利用统计学筛选方法从PCC点谐波电流测量值中筛选出用户主导谐波电流波动量,以此估计系统谐波阻抗;采用用户谐波电压发射水平修正公式消除背景谐波的影响。对理论模型和实际工程算例的仿真证明该文方法的正确性和有效性。
