Introduction The importance about the edge plasma rotation is mainly shown in the L-H *** measurement by the passive spectroscopy of inherent impurity ions doesn't affect the plasma in *** it is chosen as a conven...
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Introduction The importance about the edge plasma rotation is mainly shown in the L-H *** measurement by the passive spectroscopy of inherent impurity ions doesn't affect the plasma in *** it is chosen as a conventional diagnostic on *** a spectral diagnostic control system(SDCS) is developed to implement the automatic process of the edge rotation diagnostic system on J-TEXT tokamak.
Introduction The study of CarbonⅢ(CⅢ) radiation is of benefit to the research of tokamak edge physics and the amelioration of tokamak *** J-TEXT tokamak,a PDA array is used for detecting plasma CⅢradiation,and its ...
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Introduction The study of CarbonⅢ(CⅢ) radiation is of benefit to the research of tokamak edge physics and the amelioration of tokamak *** J-TEXT tokamak,a PDA array is used for detecting plasma CⅢradiation,and its characteristics in high density are studied. Experimental results In J-TEXT,oscillation of CⅢsignal is observed when a kind of big sawtooth appears on soft x-ray in high density state,as shown in Fig.1.
Focusing on the needs of radiated power measurement in J-TEXT tokamak,we designed a current preamplifier with stable performance for the weak signal from the AXUV detector. The amplifier circuit adopts a composite str...
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Focusing on the needs of radiated power measurement in J-TEXT tokamak,we designed a current preamplifier with stable performance for the weak signal from the AXUV detector. The amplifier circuit adopts a composite structure so as to suppress the high frequency noise.A photoelectric detection test system composed of a laser light source and an optical chopper is *** bandwidth and the stability of the equipment set including the current preamplifier and AXUV detector are tested by the test system *** the test on the preamplifier individually by a current source,it is found that an oscillating signal can easily arise in the test with AXUV *** phenomenon comes from the parasitic capacitance of the detector by a detailed analysis from the circuit's transfer *** a systematic test and analysis,we developed an amplifier with the gain of 5.1×10~5V/A,the bandwidth of 10 *** the same time,the amplifier can ensure the system stability and signal undistorted ***,due to the terrible electromagnetic environment in the J-TEXT tokamak,the methods of grounding, shielding and wire layout were analyzed and *** noise level is decreased to less than 20mV while *** experimental tests in J-TEXT tokamak indicate that the amplifier can provide a precise result about the sawtooth and precursor oscillation phenomena on the radiation signal.
Summary form only given. Due to several urgent applications, room temperature atmospheric pressure plasma jets (RT-APPJs) have attracted lots of interest worldwide in the past decade and many different types of RT-APP...
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Summary form only given. Due to several urgent applications, room temperature atmospheric pressure plasma jets (RT-APPJs) have attracted lots of interest worldwide in the past decade and many different types of RT-APPJs have been reported. One of the most interesting phenomena of RT-APPJs, i.e. “plasma bullet” behavior has been studied by many different groups. We know much more about the “plasma bullet” now than in the beginning. In this paper, an overview of the research on the “plasma bullet” behavior will be presented, which including the effect of the photoionization, seed electrons, Penning ionization, gas flow rate, polarity of the applied voltage, pulse rising time, pulse repetition frequency, and pulse width. In addition, some newly discovered “plasma bullet” phenomena, including the multiple bullets for a single voltage pulse, dragon shape propagation path, and virtual electrode propagation of the plasma plume are reported 1-5 .
Summary form only given. Plasma induced by electron beam (EB) have been receiving widely attentions for its attractive features compared with traditional plasma generation techniques such as dielectric barrier dischar...
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Summary form only given. Plasma induced by electron beam (EB) have been receiving widely attentions for its attractive features compared with traditional plasma generation techniques such as dielectric barrier discharge, electron cyclotron resonance and the surface wave 1 . This plasma source has higher ionization and dissociation efficiencies and can generate large scale non-equilibrium plasma at high pressure. Besides, by using high energy electron beam, it is convenient to control the electron density via modulation of beam parameters such as the beam energy. In this paper, a large scale non-equilibrium plasma, Fig. 1 which has a diameter of 50 cm and length of 35 cm at 20 kPa N 2 induced by electron beam is reported. The experimental results are consistent with the results simulated by software EGSnrc. The emission spectra reveals that the plasma contains abundant excited N* 2 and N + 2 . It is similar to the traditional plasma generation techniques such as pulse discharge. The rotational and vibrational temperature of the plasma next to the electron beam entrance is about 550 and 1700 K, respectively. The results of time evolution experiment show that there are no obvious influences of space charge on this plasma.
A 100kV/60A high-voltage power supply (HVPS) has been established to energize the electron cyclotron resonance heating (ECRH) system for J-TEXT tokamak. With the pulse step modulation (PSM) technology, the HVPS has ma...
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ISBN:
(纸本)9781479901708
A 100kV/60A high-voltage power supply (HVPS) has been established to energize the electron cyclotron resonance heating (ECRH) system for J-TEXT tokamak. With the pulse step modulation (PSM) technology, the HVPS has many advantages, especially the low stored energy and short protective time in case of short-circuit fault. This paper gives a description and key design features for the isolated transformers, switch power supplies (SPS) modules, measurement equipments and controller. In this HVPS, 4 dry-type transformers with 36 secondary-windings drive the 144 series SPS modules and isolate the high voltage between the rectifiers and the 6.3kV AC bus. A controller based on the PXI technology, which conforms to the ITER CODAC standard, has been developed to operate the series switches in each SPS module. The error signals from all the modules are monitored by the controller and the fast protection responses any over current fault in less than 5 μs. Moreover, to acquire better dynamic response and stability, a control strategy improved from the conventional PWM phase-shift modulation method has been proposed. The experimental results are also presented and show that the power supply system performing good.
Room temperature atmospheric pressure plasma jets (RTAPP-Js) have widespread biomedical and health care applications in pathogen inactivation, wound healing, blood coagulation, and interventional oncology, to mention ...
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Room temperature atmospheric pressure plasma jets (RTAPP-Js) have widespread biomedical and health care applications in pathogen inactivation, wound healing, blood coagulation, and interventional oncology, to mention just a few. The overwhelming majority of the existing RTAPP-Js rely on external power (e.g., generators or wall power) and gas feed (e.g., He or Ar gas) supply. This limits their utility in mobile handheld devices for point-of-care applications, e.g., in natural disaster rescue and military combat operations, treatments in remote locations, etc. Moreover, treatment efficacy of such devices should be comparable or superior to current equipment. Recently, Pei et al. have developed a handheld RTAPP-Js (named “Plasma Flashlight”) powered by a 12 V DC battery 1 . The plasma source does not rely on any external power or feedstock gas supplies. In this report, we quantitative measured the O 3 density of the Plasma Flashlight by absorption spectroscopy which was performed with a standard mercury lamp. Atom O and OH radicals that play a crucial role in the inactivation process were measured using the laser-induced fluorescence (LIF) technology. The distribution of Atom O and OH radicals in the plasma plum was also studied.
As a result of world's energy resources crisis and environment pollution increasingly aggravating, distributed generation (DG) based on renewable energy has become a developmental trend for electric power industry...
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As a result of world's energy resources crisis and environment pollution increasingly aggravating, distributed generation (DG) based on renewable energy has become a developmental trend for electric power industry in 21 century. However, DG's are usually affected by natural conditions being not able to output power continuously and steadily, so when large scale wind turbine generators are incorporated into the grid there is likely attendance impact it would bring on electric power system stability. In this investigation, the wind farm connection was done at 33/1 1kV level at Kastina substation located at Northern part of Nigeria. This paper is to establish voltage instability and frequency fluctuation that might be associated with the connection of the wind farm to the existing grid. The DigSILENT Power Factory software was used for modeling and simulation analysis of the studies and the results shows that when wind farm is connected to the grid, large clearance time is required for the fault to be cleared for voltage and frequency to become normalize again as compare with normal grid system. The studies has verified transient stability associated problem due to voltage and frequency stability variation phenomenon during the disconection of both windfarm and the load from the existing grid and is easier to predict in future the setting of protective devices and clearance time.
In order to ensure the safety of DFIG when severe fault happens, crowbar protection is adopted. But during slight fault condition, the crowbar protection will not trip, and the DFIG is still excited by AC-DCAC convert...
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Theoretical research and equipment development of traveling-wave fault location seriously depend on digital simulation. Meanwhile, the fault-generated transient traveling wave must be transferred through transmission ...
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