“channel”的概念、定义、翻译、参考文献-科学参考

channel

Physics

1. The region between the source and the drain in a field-effect transistor. The conductivity of the channel is controlled by the voltage applied to the gate.

2. A path, or a specified frequency band, along which signals, information, or data flow.

Chemical Engineering

A trough used for the passage or transport of liquids, usually with a free surface. That is, there is a gas or vapour such as air above the surface of the liquid. The cross section of the channel is usually square, trapezoidal, or semi-circular.

Computer

1. In telecommunications in general, a separate path through which signals can flow.
2. In the public switched telephone network (PSTN), one of multiple transmission paths within a single link between network points.
3. In mainframe parlance, a specialized processor that comprises an information route and associated circuitry to control input and/or output operations. It normally provides for formatting and buffering and has the necessary control to meet the timing requirements of an I/O device.
Several different I/O devices may be connected to one channel and the control circuitry within the channel directs the data streams to or from the appropriate device. If the I/O devices have a relatively slow data rate, then a multiplexer channel is used in which transfers to or from the separate devices are interleaved, character by character, such that several devices can work simultaneously.
When a number of devices with high data rates, e.g. magnetic disk and tape, are to be connected, a selector channel is used. This will transfer a complete record to or from a device before reselecting.
A channel is often a wired-program processor. As channels have become more elaborate they have tended to become programmed computers (I/O processors) in themselves. See also peripheral processor.
4. A greyscale digital image equivalent to one of the components of a colour image. For example, an RGB image consists of red, green, and blue channels.
5. On the World Wide Web, a pre-defined website that can automatically send updated information for immediate display or viewing on request.
6. In computer marketing, a ‘middleman’ between a product creator and the marketplace. This is distinct from direct selling where the manufacturer sells directly to the end user. Value-added resellers (VAR) and retail store chains are examples of channels in this context.
7. In a field-effect transistor (FET), the path in the semiconductor through which current flows.

Internet

An alternative name for a transmission line.

Electronics and Electrical Engineering

1. A specified frequency band or a particular path used in communications for the reception or transmission of electrical signals.
2. A route along which information may travel or be stored in a data-processing system or a computer.
3. (in a field-effect transistor) The region connecting source and drain, the conductivity of which is modulated by the gate voltage.
4. (in a p-n-p bipolar junction transistor) The spurious extension of n-type base across the surface of the collector to the edge of the chip. This results in excessive leakage currents and may be overcome using a channel stopper. The inevitable presence of positive charges at the interface of the high-resistivity p-type collector with the passivating oxide layer causes the formation of the n-type channel on the surface of the collector.

Geology and Earth Sciences

1. The preferred linear route along which surface water and groundwater flow is usually concentrated (although water can flow across wide, flat surfaces as sheet flow). It is commonly a linear, concave-based depression (e.g. river channel, submarine fan channel). The geometry may be sinuous, anastomosing, or straight, and with a widely variable width-to-depth ratio. See braided stream; meander.
2. A narrow sea-way connecting two wider bodies of water (e.g. the English Channel).
3. In remote sensing, the range of wavelengths recorded by a single detector to form an image.

Geography

A watercourse. The nature of any river channel is a result of the interaction of: the material properties of the bed and banks; the flow hydraulics; and sediment transport within the river. Any alteration in any one of them affects the other two. Narrow, stable channel stretches are linked to finer bed material and high levels of river vegetation; wider, unstable channels are associated with larger bed material and less riparian vegetation (Rowntree and Dollar (1996) S. Afric. Geog. J. 78, 1).
The Smith and Bretherton (1972, Water Resources Res. 8, 1506) explanation of channel initiation is based on the continuity equation for sediment transport. Its central result is a criterion for an infinitesimal perturbation on the surface to begin to grow. See also Smith (2000) Computers and Geoscience 26, 541.
For more mature landscapes, channel extent is based on competition between diffusion and runoff processes: a channel is initiated once the magnitude of incising runoff processes exceeds the magnitude of infilling diffusion processes, such as creep, rainsplash, and shallow landsliding; see Tucker and Bras (1998) Water Resources Res. 34, 2751–64.
The channel capacity of a river is its cross-sectional area in square metres, but the borders of a channel are not easy to establish; see Rajaguru et al. (1995) ESPL 20. Channel resistance slows or impedes the flow; friction with the bed is the major cause. See Righetti and Armanini (2002) J. Hydrol. 269, 1 and Wohl (2007) Phys. Geog. 28, 3.

单词	channel
释义	channel Physics 1. The region between the source and the drain in a field-effect transistor. The conductivity of the channel is controlled by the voltage applied to the gate. 2. A path, or a specified frequency band, along which signals, information, or data flow. Chemical Engineering A trough used for the passage or transport of liquids, usually with a free surface. That is, there is a gas or vapour such as air above the surface of the liquid. The cross section of the channel is usually square, trapezoidal, or semi-circular. Computer 1. In telecommunications in general, a separate path through which signals can flow. 2. In the public switched telephone network (PSTN), one of multiple transmission paths within a single link between network points. 3. In mainframe parlance, a specialized processor that comprises an information route and associated circuitry to control input and/or output operations. It normally provides for formatting and buffering and has the necessary control to meet the timing requirements of an I/O device. Several different I/O devices may be connected to one channel and the control circuitry within the channel directs the data streams to or from the appropriate device. If the I/O devices have a relatively slow data rate, then a multiplexer channel is used in which transfers to or from the separate devices are interleaved, character by character, such that several devices can work simultaneously. When a number of devices with high data rates, e.g. magnetic disk and tape, are to be connected, a selector channel is used. This will transfer a complete record to or from a device before reselecting. A channel is often a wired-program processor. As channels have become more elaborate they have tended to become programmed computers (I/O processors) in themselves. See also peripheral processor. 4. A greyscale digital image equivalent to one of the components of a colour image. For example, an RGB image consists of red, green, and blue channels. 5. On the World Wide Web, a pre-defined website that can automatically send updated information for immediate display or viewing on request. 6. In computer marketing, a ‘middleman’ between a product creator and the marketplace. This is distinct from direct selling where the manufacturer sells directly to the end user. Value-added resellers (VAR) and retail store chains are examples of channels in this context. 7. In a field-effect transistor (FET), the path in the semiconductor through which current flows. Internet An alternative name for a transmission line. Electronics and Electrical Engineering 1. A specified frequency band or a particular path used in communications for the reception or transmission of electrical signals. 2. A route along which information may travel or be stored in a data-processing system or a computer. 3. (in a field-effect transistor) The region connecting source and drain, the conductivity of which is modulated by the gate voltage. 4. (in a p-n-p bipolar junction transistor) The spurious extension of n-type base across the surface of the collector to the edge of the chip. This results in excessive leakage currents and may be overcome using a channel stopper. The inevitable presence of positive charges at the interface of the high-resistivity p-type collector with the passivating oxide layer causes the formation of the n-type channel on the surface of the collector. Geology and Earth Sciences 1. The preferred linear route along which surface water and groundwater flow is usually concentrated (although water can flow across wide, flat surfaces as sheet flow). It is commonly a linear, concave-based depression (e.g. river channel, submarine fan channel). The geometry may be sinuous, anastomosing, or straight, and with a widely variable width-to-depth ratio. See braided stream; meander. 2. A narrow sea-way connecting two wider bodies of water (e.g. the English Channel). 3. In remote sensing, the range of wavelengths recorded by a single detector to form an image. Geography A watercourse. The nature of any river channel is a result of the interaction of: the material properties of the bed and banks; the flow hydraulics; and sediment transport within the river. Any alteration in any one of them affects the other two. Narrow, stable channel stretches are linked to finer bed material and high levels of river vegetation; wider, unstable channels are associated with larger bed material and less riparian vegetation (Rowntree and Dollar (1996) S. Afric. Geog. J. 78, 1). The Smith and Bretherton (1972, Water Resources Res. 8, 1506) explanation of channel initiation is based on the continuity equation for sediment transport. Its central result is a criterion for an infinitesimal perturbation on the surface to begin to grow. See also Smith (2000) Computers and Geoscience 26, 541. For more mature landscapes, channel extent is based on competition between diffusion and runoff processes: a channel is initiated once the magnitude of incising runoff processes exceeds the magnitude of infilling diffusion processes, such as creep, rainsplash, and shallow landsliding; see Tucker and Bras (1998) Water Resources Res. 34, 2751–64. The channel capacity of a river is its cross-sectional area in square metres, but the borders of a channel are not easy to establish; see Rajaguru et al. (1995) ESPL 20. Channel resistance slows or impedes the flow; friction with the bed is the major cause. See Righetti and Armanini (2002) J. Hydrol. 269, 1 and Wohl (2007) Phys. Geog. 28, 3.
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