In order to eliminate influence of the carriers on the evaporation of rare earth elements in DC arc,a de- vice which introduces axially the sample aerosol has been designed to study the effects of controlled-atmos- ph...In order to eliminate influence of the carriers on the evaporation of rare earth elements in DC arc,a de- vice which introduces axially the sample aerosol has been designed to study the effects of controlled-atmos- phere,discharge current,electrode polarity and introduction direction of aerosol on the emission of rare earth elements in DC arc discharge.The influence of various matrices and carriers on the line density and excitation condition of rare earth elements have also been studied,then the related excitation mechnism is proposed.展开更多
A direct current（DC） source excited plasma jet consisting of a hollow needle anode and a plate cathode has been developed to form a diffuse discharge plume in ambient air with flowing argon as the working gas.Using ...A direct current（DC） source excited plasma jet consisting of a hollow needle anode and a plate cathode has been developed to form a diffuse discharge plume in ambient air with flowing argon as the working gas.Using optical and electrical methods,the discharge characteristics are investigated for the diffuse plasma plume.Results indicate that the discharge has a pulse characteristic,under the excitation of a DC voltage.The discharge pulse corresponds to the propagation process of a plasma bullet travelling from the anode to the cathode.It is found that,with an increment of the gas flow rate,both the discharge plume length and the current peak value of the pulsed discharge decrease in the laminar flow mode,reach their minima at about1.5 L/min,and then slightly increase in the turbulent mode.However,the frequency of the pulsed discharge increases in the laminar mode with increasing the argon flow rate until the argon flow rate equals to about 1.5 L/min,and then slightly decreases in the turbulent mode.展开更多
Time moments have been introduced in automatic control because of the analogy between the impulse response of a linear system and a probability function. Pasek described a testing procedure for determining the DC para...Time moments have been introduced in automatic control because of the analogy between the impulse response of a linear system and a probability function. Pasek described a testing procedure for determining the DC parameters from the current response to a step in the armature voltage motor. In this paper, two identification algorithms developed based on the moments and Pasek's methods are introduced and applied to the parameter identification of a DC motor. The simulation and experimental results are presented and compared, showing that the moments method makes the model closer to reality, especially in a transient regime.展开更多
文摘In order to eliminate influence of the carriers on the evaporation of rare earth elements in DC arc,a de- vice which introduces axially the sample aerosol has been designed to study the effects of controlled-atmos- phere,discharge current,electrode polarity and introduction direction of aerosol on the emission of rare earth elements in DC arc discharge.The influence of various matrices and carriers on the line density and excitation condition of rare earth elements have also been studied,then the related excitation mechnism is proposed.
基金supported by National Natural Science Foundation of China(Nos.10805013,11375051)Funds for Distinguished Young Scientists of Hebei Province,China(No.A2012201045)+1 种基金Department of Education for Outstanding Youth Project of China(No.Y2011120)Youth Project of Hebei University of China(No.2011Q14)
文摘A direct current（DC） source excited plasma jet consisting of a hollow needle anode and a plate cathode has been developed to form a diffuse discharge plume in ambient air with flowing argon as the working gas.Using optical and electrical methods,the discharge characteristics are investigated for the diffuse plasma plume.Results indicate that the discharge has a pulse characteristic,under the excitation of a DC voltage.The discharge pulse corresponds to the propagation process of a plasma bullet travelling from the anode to the cathode.It is found that,with an increment of the gas flow rate,both the discharge plume length and the current peak value of the pulsed discharge decrease in the laminar flow mode,reach their minima at about1.5 L/min,and then slightly increase in the turbulent mode.However,the frequency of the pulsed discharge increases in the laminar mode with increasing the argon flow rate until the argon flow rate equals to about 1.5 L/min,and then slightly decreases in the turbulent mode.
文摘Time moments have been introduced in automatic control because of the analogy between the impulse response of a linear system and a probability function. Pasek described a testing procedure for determining the DC parameters from the current response to a step in the armature voltage motor. In this paper, two identification algorithms developed based on the moments and Pasek's methods are introduced and applied to the parameter identification of a DC motor. The simulation and experimental results are presented and compared, showing that the moments method makes the model closer to reality, especially in a transient regime.
