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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soapstone. A soft, grayish-white stone composed of talc and chlorite, a mineral similar to mica. Soapstone has a slick, or soapy, feel that gives it its name. soaring (aircraft flight). A type of flight in which the aircraft, usually a glider or sailplane, flies without the use of engine power. The aircraft is normally pulled into the air with a powered airplane and, when released, it glides down. The pilot circles in a column of rising air, and as long as the air is rising faster than the aircraft is descending, the aircraft goes up in altitude. As soon as an altitude is reached where the air is no longer rising, the pilot leaves that column and searches out another, to continue the flight. socket-head bolt. A bolt with a socket, usually hexagon-shaped, formed in its head. A hexagon wrench that fits into the socket is used to turn a socket-head bolt. socket wrench. A type of wrench used to turn a nut or bolt. The socket is a small cylinder of high-strength chrome-vanadium steel. One end of the cylinder has either a 6-point or 12-point opening that fits the nut or bolt head. The other end has a square hole that fits the handle used to drive the socket. These drive holes are usually 1/4-inch, 3/8-inch, 1/2-inch, or 3/4-inch square, depending on the size nut the socket is designed to turn. Ratchet handles, breakover handles, and speed handles can be used to drive the socket. Extensions of various lengths, and universal joints may be used between the socket and the drive handle to allow the socket to fit squarely on the nut and be turned by the handle. sodium. A soft, light, malleable, ductile, silvery-white, metallic chemical element that has a waxy feel. Sodium’s symbol is Na, its atomic number is 11, and its atomic weight is 22.9898. Sodium is in the alkaline metal group and is extremely active, combining readily with other chemical elements. Pure sodium metal combines instantly with oxygen when it is exposed to air, and it causes water to decompose with a violent reaction. Because of this, sodium metal must be kept covered with kerosine. sodium bicarbonate. A white, powdery salt of sodium. When mixed with water, sodium bicarbonate forms a weak alkaline solution. Sodium bicarbonate is useful for neutralizing spilled battery acid and as a fire extinguishing agent. When sodium bicarbonate is heated, it releases carbon dioxide that smothers the fire. Other names for sodium bicarbonate are baking soda and saleratus. sodium-filled exhaust valve (reciprocating engine component). A hollow exhaust valve that is partially filled with metallic sodium. The sodium is a soft solid at room temperature, but at the operating temperature of the valve, it melts and becomes a liquid that wets the inside surfaces of the hollow valve stem and head. As the valve opens and closes, the sodium sloshes back and forth, picking up heat from the head and carrying it into the stem, where it is transferred through the valve guide into the cylinder head and is subsequently dissipated into the air. |
