时间：2011-03-11 23:18来源：蓝天飞行翻译 作者：航空 点击：次
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plasma torch. A torch in which plasma gas is injected into an electric arc formed between two electrodes in a chamber. The stream of hot gases leaves the torch at an extremely high speed through an orifice in the negative electrode. This high-velocity, high-temperature stream can be used for welding, cutting, or spraying molten metal. The temperature produced by a plasma torch can be as high as 60,000°F. plasticizer (finishing material constituent). Materials used in a lacquer finishing system to give the film flexibility and resilience. plastic (material condition). The condition in which a material is capable of being shaped or formed. A material in its plastic condition is normally in a semi-solid state. plastics. The generic name for any of the organic materials produced by polymerization. Plastics can be shaped by molding or drawing. Plastic Wood. The registered trade name for a form of wood filler made of wood fibers mixed with a synthetic resin. Plastic wood is used to fill cracks and holes in wood. When it hardens, it can be worked with ordinary woodworking tools and can be finished to match the wood it is used to fill. plate (electron tube component). The anode of an electron tube. A high positive voltage on the plate attracts electrons from the cathode. This flow of electrons is controlled by the voltage on grids located between the cathode and the plate. plate current (electron tube current). Current that flows between the cathode and plate in an electron tube. plate glass. A thick, flat, high-quality sheet of glass. Plate glass is used for windows where strength and undistorted vision are necessary. plate power supply (electron tube equipment). A high-voltage, positive DC power supply for electronic equipment using electron tubes (vacuum tubes). Plate power supplies are usually called B+ power supplies. plate resistance (electron tube specification). A dynamic value found by dividing the change in plate voltage by the change in plate current caused by the voltage change. No conditions other than the voltage and current are allowed to change when making this measurement. plate saturation (electron tube condition). The condition in an electron tube in which the plate, or anode, is attracting all of the electrons being emitted by the cathode. plating (metal surface treatment). The process in which a thin coating of one metal is electrolytically deposited on the surface of another. Cadmium and chromium are used to plate steel parts to protect the steel from corrosion. Chromium also makes the surface of the steel resistant to wear. platinum. A heavy, silvery-white, metallic chemical element that is resistant to nearly all acids. Platinum’s symbol is Pt, its atomic number is 78, and its atomic weight is 195.09. Because platinum is able to withstand extremely high temperatures, it is used as the electrodes in some fine-wire spark plugs. Platinum’s appearance is pleasing, and it is so durable it is used for jewelry. |
