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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screeding tool. A tool used when working with plastic resins, to spread the resin evenly over a surface and level it. Screeding tools are often made of some form of polyvinylchloride plastic material that releases the resin, making the tool easy to clean. screen grid (electron tube component). The grid in an electron tube between the control grid and the plate (anode). The screen grid has a positive voltage on it slightly lower than the voltage on the plate. The steady positive voltage on the screen grid minimizes voltage feedback from the plate to the control grid through the interelectrode capacitance. screwdriver. A hand tool used to install or remove screws. The bit of a screwdriver may be in the form of a straight, flat-edged blade, or it may be fluted to fit into a recessed-head screw. A screwdriver has a handle on its shank in line with the blade, but on the opposite end. The bit of the screwdriver fits into the slot or recess in the head of the screw, and the handle is twisted to turn the screw. screw-pitch gage. A set of thin metal blades with a series of V-shaped notches cut along one edge of each blade. The notched edge of each gage is compared with the thread being checked until one is found that exactly meshes with it. The number marked on the gage that fits the threads shows the number of threads per inch in the nut or on the bolt. scriber. A sharp-pointed tool used to scribe (mark) lines on metal. scud (meteorology). A commonly used term for small patches of low clouds that often form below a heavy overcast. scuffing. A severe type of damage to moving parts caused when one metal part moves across another without sufficient lubricant between them. Enough heat is generated by friction to cause the high points of the surfaces to weld together, and continued movement tears, or scuffs, the metal. scupper (fuel tank component). A recess around the filler neck of an aircraft fuel tank. Any fuel spilled when the tank is being filled collects in the scupper and drains to the ground through a drain line, rather than flowing into the aircraft structure. sea anchor. An open-bottom canvas bucket towed behind a boat or seaplane in the water. A sea anchor causes a large amount of drag and is used to reduce the drift and to aid in maneuvering the vessel. sea breeze (meteorology). A coastal breeze blowing from sea to land. Sea breezes are caused by the temperature difference when the land surface is warmer than the sea surface. sea fog (meteorology). A type of advection fog that forms when air that has been lying over a warm land surface moves over a colder water surface. seal. A component used to prevent fluid leaking between two surfaces. If there is relative movement between the surfaces, the seal is called a packing. If there is no movement between the surfaces, it is called a gasket. sealant. A heavy liquid or paste spread between two surfaces to form a seal. Sealant may be used with a gasket or, in some instances, instead of a gasket. |
