A plasma source with a combined cathode

Results are presented of an experimental investigation of a plasma source the central electrode of which consists of a combination of a copper cylindrical cathode with a heated tungsten cathode at the end; the tests were conducted in argon and helium at currents of 0.4-3.0 kA.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol.21, No. 5, pp. 855–861, November, 1971.     

Investigation of heat fluxes in a pulsed plasma accelerator

We determine the thermal state of the structure elements and estimate the energy distribution in a coaxial plasma injector operating under pulsed conditions. It is demonstrated that the insulator temperature affects the main parameters of the plasma jet.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 18, No. 3, pp. 534–537, March, 1970.     

Spectral diagnostics of plasma discharge between a metal cathode and liquid anode

The results from studies of an electric discharge between a metal cathode and liquid anode at atmospheric pressure are presented. We investigate the discharge shape, the plasma emission spectrum, the electron concentration and temperature, and the molecule temperature; we analyze the continuous emission in the plasma spectrum and perform infrared thermography.     

Interaction of plasma jets in a two-jet electric arc

The interaction of plasma jets in a two-jet electric arc was analyzed based on the results of the numerical solution of magnetogasdynamic equations in a plane parallel approximation of an equilibrium plasma. The role of the mass, heat, and charge transfer processes in the formation of the calculated two-jet arc structure has been established which qualitatively agrees with the experimentally observed properties.     

Generation of a homogeneous plasma in a glow discharge with a hollow anode and a wide-aperture hollow cathode

The principles for designing electrode systems for sources of ion beams of large cross section on the basis of a glow discharge are considered, and a system with combined magnetic and electrostatic confinement of the fast electrons in a wide-aperture hollow cathode and the generation of an ion-emitting plasma in the anode cavity is proposed. It is shown that the system investigated generates a plasma with a nearly homogeneous distribution of the ion emission current density at low gas pressures and can be effectively used to obtain ion beams over a broad range of energies. Pis’ma Zh. Tekh. Fiz. 25, 83–88 (June 26, 1999)     

Enhanced emission during submillisecond low-energy electron beam generation in a diode with grid-stabilized plasma cathode and open anode plasma boundary

We have experimentally studied the phenomenon of emission enhancement in a gas-filled diode with grid-stabilized plasma cathode and open (mobile) anode plasma boundary at an accelerating voltage of up to 20 kV. As the working gas pressure is increased to p ≥ 10⁻² Pa and the longitudinal magnetic field is increased to B _z ≥ 20 mT, the current in the accelerating gap exhibits significant growth, sometimes by a factor of two or more. Experimental data show that the most probable mechanism responsible for this effect is ion-induced secondary electron emission from the emitting electrode surface bombarded by ions from plasma generated by the electron beam in the drift space. These ions are accelerated in the space charge layer between the emitting electrode surface and the mobile boundary of the beam-generated (anode) plasma.     

Thin film deposition using a plasma source with a hot refractory anode vacuum arc

Vacuum arc generated plasma was used to deposit metallic Al, Zn, and Sn coatings on glass substrates. An arc mode with a refractory anode and an expendable cathode (the “hot refractory anode vacuum arc”), overcomes macroparticle (MP) contamination experienced in other arc modes. I = 100–225 A arcs were sustained between a water-cooled coating source cathode and an anode, which was heated by the arc, separated from each other by a 10-mm gap, for times up to 150 s. The distance from the arc axis to the substrate (L) was 80–165 mm. Film thickness was measured with a profilometer. It was found that the deposition rate increased with time to a peak, and then decreased to a steady-state value. The peak occurred earlier when using short anode (9 mm long), e.g., with the Al cathode, L = 110 mm, and I = 200 A, the peak was at t _p = 15 s after arc ignition while with the long anode t _p = 45 s. t _p decreased with I, from 45 s with I = 100 A, to 10 s with I = 225 A with the short anode. The peak is believed to appear due to initial condensation of cathode material (including MPs) on the cold anode, and its subsequent evaporation as the anode heated. In the later HRAVA steady state, a balance between condensation and evaporation on the anode is established. The deposition rate peak was significant with low melting temperature Al and Zn cathodes, which produce many MPs, and negligible with Cu and Ti cathodes.     

Formation of quasisteady supersonic flow with a pulse-periodic plasma heat source

An analysis is made of experimental data on the influence of a pulse-periodic optical discharge in a supersonic argon stream on the aerodynamic drag of streamlined objects. The interrelation established between the parameters of the laser radiation and the stream is used to determine the threshold frequency of the laser pulses which determines the transition to quasi-steady-state flow. Pis’ma Zh. Tekh. Fiz. 24, 8–13 (August 26, 1998)     

Polymer pre-treatment by linear anode layer source plasma for adhesion improvement of sputtered TiN coatings

The pre-treatment of work-piece surfaces is decisive for improved adhesion of tribological, decorative, sensor, biocompatible, etc. coatings subsequently deposited by vacuum coating techniques. Most current industrial techniques (mainly glow discharges) miss the requirements for activating temperature-sensitive and electrically insulating materials. Gridless plasma sources like the linear anode layer ion source are an excellent alternative due to their low investment and operating costs and scalability to many industrial applications, and also due to the measured plasma characteristics (low surface charging, broad energy distribution). The appreciable increase of adhesion by anode layer source plasma pre-treatment and the effects of ion energy and gas composition are presented for room temperature sputtered titanium nitride coatings polyamide, polycarbonate, and poly(ethyleneterephtalate). For these polymers, the oxygen-based functionalization (chain-scissoring and cross-linking) strongly influence the wetting behaviour and improve the adhesion by suppressing adhesive cracking at low scratching loads. Low O₂ contents in Ar-O₂ discharge of ∼400 eV average ion energy lead to best coating adhesion.     

Atomic oxygen in remote plasma of radio-frequency hollow cathode discharge source: Characterization and efficiency

Low-pressure, low-temperature remote oxygen plasma ignited by a radio-frequency (RF) hollow cathode discharge (HCD-L300) system is shown to be a powerful and effective source of neutral atomic oxygen (AO), useful in processing of polymeric materials. The density of AO was determined by a catalytic nickel probe as a function of pressure, RF power, oxygen flow rate and axial distance in the processing chamber. It was found to vary between ∼1×10¹⁹ to ∼1×10²⁰ atom m⁻³. The AO rich remote plasma-induced modification of wetting properties of polyimide (PI) and fluorinated ethylene propylene (FEP) surfaces has also been investigated. The wetting properties of the PI and FEP surfaces before and after exposure to the plasma were characterized by contact angle measurements and analysis. It was found that the influence of plasma surface treatment on wetting properties of FEP has an opposite effect to that of PI. On increasing the time of treatment, the surface of PI becomes more hydrophilic, whereas the hydrophobicity of FEP surface enhances. Moreover, a superhydrophobic FEP surface is produced at prolonged time of treatment. Changes in the surface morphology due to the plasma treatment were viewed under a scanning electron microscope (SEM).     

Model of glow discharge between an electrolytic anode and a metal cathode

High Temperature - The results of the numerical simulation of the glow discharge between the pin cathode and the electrolytic anode are presented. The electron concentration distribution for the...     

Peculiarities of electric discharge between jet anode and metal cathode

We present the results of a DC electric discharge experimental study between a jet anode and copper cathode at atmospheric pressure. We found the essential influence of the jet anode flow nonuniform character on the discharge development for different power supply regimes. Discharge burning peculiarities are revealed in the jet regime at different power supply voltages with small fluctuation in the milli-, micro-, and nanosecond ranges of the time sweep. We also determined temperatures at the copper cathode surface and its atomization. By means of the Fourier transformation, we reveal the frequency spectrum of the discharge current oscillations.     

冷阴极潘宁离子源的磁路研究

研究了冷阴极潘宁离子源的磁路设计，在简要叙述冷阴潘宁离子源的基本原理及其对磁场要求的基础上，考虑了在设计冷阴极潘宁离子源磁路时的关键问题和解决方法，并给出了实验结果和分析结论。     

Stable homogeneous microdischarge at atmospheric pressure between a flat cathode and point anode

Conditions of stable operation of a homogeneous glow microdischarge in air at atmospheric pressure between a flat cathode and point anode are established and realized at interelectrode gap widths within ～1–30 μm and discharge currents within from ～10^?4 to 1 A.     

Calculation of the operation of a metallohydride refrigerator and optimization of the switching time for heat fluxes

A mathematical model permitting the calculation of heat and mass transfer processes in a metallohydride refrigerator is proposed. An algorithm for determining the optimum switching time for the heat fluxes in the system is developed for a prescribed cycle time from the condition of producing the maximum refrigeration effect per unit heat supplied from a high-temperature source.A. A. Blagonravov Institute of Machine Research, Moscow. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 67, Nos. 3–4, pp. 266–274, September–October, 1994.     

A multichannel discharge between a stream electrolytic cathode and a metal anode at atmospheric pressure

An experimental investigation is performed of the structure and current-voltage characteristics (CVC) of a multichannel discharge (MD) between a stream electrolytic cathode (SEC) and a metal anode, as well as of the density of SEC and anode current in a wide range of values of current I = 0.02–10 A, interelectrode spacing l = 5–50 mm, and anode diameter d _a = 5–40 mm. The development of cathode spots on the SEC surface is studied. It is found that a cathode spot of SEC may have various shapes and structures (regular circle, horseshoes, filamentary spots, and so on). The CVC of a multichannel discharge between SEC and metal anode depends significantly on I, l, and d _a , as well as on the material of the anode and on the composition and concentration of electrolyte. The dependence of the density of SEC current on discharge current is nonmonotonic. It is for the first time that a bundle-like MD between SEC and metal anode and multichannel and diffuse discharges between the plasma region and stream electrolytic cathode are observed, and their characteristics are investigated.     

Dense plasma formation on the surface of a ferroelectric cathode

An enhanced electron emission mode of the ferroelectric plasma cathode operation is reported. The enhanced emission is achieved due to the generation of dense plasma (10¹⁹-10²⁰ m⁻³). This plasma is formed by a flashover which is initiated by charged particles. These particles are attracted to the ferroelectric surface by a driving electric field and are released during its decay. Generation of an electron beam with current amplitude ?2.5 kA is demonstrated in a diode under an accelerating voltage of 150-300 kV and pulse duration of 300 ns.     

某大楼空调冷热源方案比较

综合考虑地域特征、项目特性,使用特性和社会效益,通过比较冷机组,燃气锅炉、溴化锂体化直燃机等多种冷热源方案的初投资和运行费用,得出最佳的冷热源方案。