翻訳と辞書 Words near each other ・ Induction coil ・ Induction cooking ・ Induction cut ・ Induction equation ・ Induction forging ・ Induction furnace ・ Induction generator ・ Induction hardening ・ Induction heater ・ Induction heating ・ Induction loop ・ Induction motor ・ Induction motors modelling in ABC frame of reference ・ Induction of regular languages ・ Induction period ・ Induction plasma technology ・ Induction programme ・ Induction puzzles ・ Induction regulator ・ Induction sealing ・ Induction shrink fitting ・ Induction training ・ Induction variable ・ Induction welding ・ Induction-recursion (type theory) ・ Inductionism ・ Inductive amplifier ・ Inductive Automation ・ Inductive bias ・ Inductive charging Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Induction plasma technology ： ウィキペディア英語版 Induction plasma technology The 1960s were the incipient period of Thermal Plasma Technology, driven by the necessity of aerospace programs. Among the various methods of thermal plasma generation, induction plasma (or inductively coupled plasma) takes up an important role. The early effort to maintain inductively coupled plasma on a stream of gas could retrospect to Babat〔G. I. Babat, Inst. Elec. Eng., London, England, 94, 27(1947)〕 in 1947, and Reed〔T. B. Reed, J. Appl. Phys., 32, 821(1961)〕 in 1961. The earlier stage of the investigations was concentrated in the fundamental studies of the energy coupling mechanism and the characteristics of the flow, temperature and concentration fields in the plasma discharge. In 1980’s, with the increasing demand for high performance materials and other scientific issues, people demonstrated high interest in applications of induction plasma technology in industrial scale production and other projects, for example, the waste treatment. Numerous research and development were devoted to bridge the gap between the laboratory gadget and the industry integration. After decades’ effort, induction plasma technology has got a firm foothold in modern advanced industry. ==The generation of induction plasma== Induction heating is a mature technology of hundred years’ history. A conductive metallic piece, inside a coil of high frequency, will be “induced”, and heated to the red-hot state. There is no difference in cardinal principle for either induction heating or “inductively coupled plasma”, only that the medium to induce, in the latter case, is replaced by the flowing gas, and the temperature obtained is extremely high, as it arrives the "fourth state of the matter”—plasma. An inductively coupled plasma (ICP) torch is essentially a copper coil of several turns, through which cooling water is running in order to dissipate the heat produced in operation. The coil wraps a confinement tube, inside which the induction plasma is generated. One end of the confinement tube is open; the plasma is actually maintained on a continuum gas flow. During induction plasma operation, the generator supplies an alternating current (ac) of radio frequency (r.f.) to the torch coil; this ac induces an alternating magnetic field inside the coil, after Ampère’s law (for a solenoid coil): $\backslash phi\_B=(\backslash mu\_0\backslash ,I\_c\backslash ,N)(\backslash pi\backslash ,r\_0^2)\backslash quad(1)$ where, $\backslash phi\_B$ is the flux of magnetic field, $\backslash mu\_0$ is permeability constant $4\backslash pi\backslash ,10^\backslash ,\backslash textrm$, $I\_c$ is the coil current, $N$ is the number of coil turns per unit length, and $r\_0$ is the mean radius of the coil turns. According to Faraday’s Law, a variation in magnetic field flux will induce a voltage, or electromagnetic force: $E=-N(\backslash Delta\backslash phi\_B/\backslash Delta\; t)\backslash quad(2)$ where, $N$ is the number of coil turns, and the item in parenthesis is the rate at which the flux is changing. The plasma is conductive (assuming a plasma already exists in the torch). This electromagnetic force, E, will in turn drive a current of density j in closed loops. The situation is much similar to heating a metal rod in the induction coil: energy transferred to the plasma is dissipated via Joule heating, j2R, from Ohm’s Law, where R is the resistance of plasma. Since the plasma has a relatively high electrical conductivity, it is difficult for the alternating magnetic field to penetrate it, especially at very high frequencies. This phenomenon is usually described as the “skin effect”. The intuitive scenario is that the induced currents surrounding each magnetic line counteract each other, so that a net induced current is concentrated only near the periphery of plasma. It means the hottest part of plasma is off-axis. Therefore, the induction plasma is something like an “annular shell”. Observing on the axis of plasma, it looks like a bright “bagel”. In practice, the ignition of plasma under low pressure conditions (<300 torr) is almost spontaneous, once the r.f. power imposed on the coil achieves a certain threshold value (depending on the torch configuration, gas flow rate etc.). The state of plasma gas (usually argon) will swiftly transit from glow-discharge to arc-break and create a stable induction plasma. For the case of atmospheric ambient pressure conditions, ignition is often accomplished with the aid of a Tesla coil, which produces high-frequency, high-voltage electric sparks that induce local arc-break inside the torch and stimulate a cascade of ionization of plasma gas, ultimately resulting in a stable plasma. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Induction plasma technology」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.