Low-temperature plasma is generated by glow discharge with a high direct current power supply and argon gas. A brush-shaped plasma source with large volume is obtained with a width of 15 mm, a thickness of 1 mm, and a length of about 18 mm. The source design and mechanism of the plasma generation are presented and discussed. The large-volume plasma source provides advantages in surface treatment, such as high working efficiency, sufficient utilization of the plasma gas, and natural cooling down. The characteristics of large volume, high energy density, and low temperature allow this kind of plasma source to be more suitable to practical applications.Index Terms-Atmospheric pressure, direct current, glow discharge, low-temperature plasma.L OW-TEMPERATURE plasmas generated by dc glow discharges at atmospheric pressure show considerable interests for a wide range of applications [1]- [3]. In this paper, we present a new design of a brush-shaped plasma device that can generate a stable homogeneous dc glow discharge plasma with large volume. The plasma source, which can run at atmospheric pressure in argon, as shown in Fig. 1, consists of a discharge chamber made of ceramic and two cylindrical metal rods (with a diameter of 0.75 mm) operating as electrodes set at a certain distance (15 mm) apart inside the discharge chamber. One of the two electrodes is connected with a ballast resistor (100 KΩ), which is used to suppress the electrical field fluctuations in the cathode region so that the stability of the atmospheric plasma source can be significantly improved through restraining the electrical current to pass through the discharge. Both suppression of the electrical field fluctuation and limitation of electrical current will prevent the discharge from glow-to-arc transition. The working gas (argon), which is controlled by a mass flow Manuscript
To reduce the dynamic responding time of cryogenic valve, and improve the reliability and security of cryogenic valve, depending on the operation principle of cryogenic valve, a dynamic responding transferring non-linear function and dynamic responding model of cryogenic valve were built based on kinetics theory. Afterwards, by means of Runge-Kutta solution method, a dynamic recursive four stages Runge-Kutta solution method was constructed by the introducing of changed step length coefficient and oblivion coefficient. Finally, this method was demonstrated and validated by a sample. Consequently, this method has provide a support for reducing dynamic responding time of cryogenic valve, and has provide an approach to rationally and exactly evaluating reliability and security of cryogenic valve.
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