“valve”的概念、定义、翻译、参考文献-科学参考

valve

Physics

See thermionic valve.

Chemical Engineering

A device used to regulate and control the rate of flow of a fluid. Used in pipes, they consist of a controlled flow area, which is activated electronically, pneumatically, or manually. There are various designs and sizes including butterfly valves, diaphragm valves, ball valves, globe valves, and gate valves. In gate valves, the flow area is adjusted by the movement of a stem to increase or decrease the available area. Globe valves have a ball with a hole that sits in the passage of flow in which the available flow area is adjusted by rotation of the ball away from the axis of the pipe. See control valve.

Electronics and Electrical Engineering

An active device in which two or more electrodes are enclosed in an envelope, usually of glass, one of the electrodes acting as a primary source of electrons. The electrons are most often provided by thermionic emission (in a thermionic valve) and the device may be either evacuated (vacuum tube) or gas-filled (gas-filled tube). The name derives from the rectifying properties of the devices, i.e. current flows in one direction only. The word valve is becoming obsolete and is being replaced by electron tube.

Biology

1. Any of various structures for restricting the flow of a fluid through an aperture or along a tube to one direction. Valves in the heart (see bicuspid valve; semilunar valve; tricuspid valve), veins, and lymphatic vessels consist of two or three flaps of tissue (cusps) fastened to the walls. The cusps are flattened to the walls to allow the normal passage of blood or lymph, but a reverse flow causes them to block the vessel or aperture, so preventing further backflow.
2. Any of the parts that make up a capsule or other dry fruit that sheds its seeds.
3. One of the two halves of the cell wall of a diatom.
4. Either of the two hinged portions of the shell of a bivalve mollusc.

Geology and Earth Sciences

1. One of the two halves of the hinged shell of brachiopods (Brachiopoda), or molluscs (Mollusca) of the class Bivalvia.
2. One half of the cell wall of a diatom.
3. A flap or other constriction that can close to ensure that a fluid flows in only one direction.

单词	valve
释义	valve Physics See thermionic valve. Chemical Engineering A device used to regulate and control the rate of flow of a fluid. Used in pipes, they consist of a controlled flow area, which is activated electronically, pneumatically, or manually. There are various designs and sizes including butterfly valves, diaphragm valves, ball valves, globe valves, and gate valves. In gate valves, the flow area is adjusted by the movement of a stem to increase or decrease the available area. Globe valves have a ball with a hole that sits in the passage of flow in which the available flow area is adjusted by rotation of the ball away from the axis of the pipe. See control valve. Electronics and Electrical Engineering An active device in which two or more electrodes are enclosed in an envelope, usually of glass, one of the electrodes acting as a primary source of electrons. The electrons are most often provided by thermionic emission (in a thermionic valve) and the device may be either evacuated (vacuum tube) or gas-filled (gas-filled tube). The name derives from the rectifying properties of the devices, i.e. current flows in one direction only. The word valve is becoming obsolete and is being replaced by electron tube. Biology 1. Any of various structures for restricting the flow of a fluid through an aperture or along a tube to one direction. Valves in the heart (see bicuspid valve; semilunar valve; tricuspid valve), veins, and lymphatic vessels consist of two or three flaps of tissue (cusps) fastened to the walls. The cusps are flattened to the walls to allow the normal passage of blood or lymph, but a reverse flow causes them to block the vessel or aperture, so preventing further backflow. 2. Any of the parts that make up a capsule or other dry fruit that sheds its seeds. 3. One of the two halves of the cell wall of a diatom. 4. Either of the two hinged portions of the shell of a bivalve mollusc. Geology and Earth Sciences 1. One of the two halves of the hinged shell of brachiopods (Brachiopoda), or molluscs (Mollusca) of the class Bivalvia. 2. One half of the cell wall of a diatom. 3. A flap or other constriction that can close to ensure that a fluid flows in only one direction.
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