“node”的概念、定义、翻译、参考文献-科学参考

node

Physics

1. (in physics) A point of minimum disturbance in a stationary-wave system.

2. (in astronomy) Either of two points at which the orbit of a celestial body intersects a reference plane, usually the plane of the ecliptic or the celestial equator (see celestial sphere).

Mathematics

See double point.
See graph, tree.

Astronomy

Either of the two points at which an orbit intersects a reference plane such as the plane of the ecliptic or of the celestial equator. The line joining these points is known as the line of nodes or nodal line. At the ascending node an orbiting body moves from south to north of the reference plane; at the descending node it moves from north to south. See also regression of nodes.

Statistics

See network.

Chemistry

A point of minimal disturbance in a wave. The definition applies to the wave function of the Schrödinger equation. As the wave function for the solution of the Schrödinger equation for the hydrogen atom can be found exactly by factorizing the overall wave function into a radial part and an angular part, the existence of nodes can be demonstrated explicitly. For a principal quantum number n, the radial part has (n – 1) nodes. Thus, the higher the energy of a quantum state, the more nodes the wave function has.
For a given value of n, each increase in the value of l results in an additional node in the overall wave function, meaning, in general, that for a given value of n, the energy increases as l increases. The hydrogen spectrum is an exception to this because of Fock degeneracy.

Computer

1. A point in a computer network where communication lines, such as telephone lines, electric cables, or optical fibres, are interconnected. The device used to make the connection(s) may be a simple electric interface—as used in a local area network. In more complex longer-distance networks a computer is required.
Node computers vary in their functional capabilities but their basic use is to switch incoming information to the necessary output line so that the information ultimately reaches its specified destination. The information may be transmitted as a whole or may be split into segments (see message switching, packet switching). When the information reaches its final destination, the node computer at this point will send it through to the recipient(s).
Nodes can also be called stations, and in many X25 networks the switching nodes are known as exchanges.
2. A substructure of a hierarchical data structure that cannot be further decomposed, e.g. a vertex in a graph or tree.

Internet

A device attached to a network. The device could be a computer or a hardware entity such as a router or bridge.

Electronics and Electrical Engineering

1. Any point, line, or surface in a distributed field at which some specified variable of a standing wave, such as voltage or current, attains a minimum value, usually zero. A partial node has a nonzero minimum. A point at which maximum magnitude is attained is an antinode.
2. (branch point) A point within an electrical network at which three or more elements are joined. See network.
3. An interconnection point in a communications network.

Biology

1. (in botany) The part of a plant stem from which one or more leaves arise. The nodes at the stem apex are very close together and remain so in species of monocotyledons that form bulbs. In older regions of the stem they are separated by areas of stem called internodes.
2. (in anatomy) A natural thickening, bulge, or distinct mass of tissue in an organ or part of the body. Examples are the sinoatrial node that controls the heartbeat (see pacemaker) and the lymph nodes.
3. (in phylogenetics) (vertex) A branch point in a phylogram.

Geology and Earth Sciences

1. A point of zero displacement in a material transmitting standing waves, produced by destructive interference between waves propagating in opposite directions.
2. In a phylogenetic tree, a representation of an extant (terminal node) or ancestral (internal node) operational taxonomic unit.

Geography

Accessibility of a node is given by the travel cost between a node and another node, or a weighted average of travel cost to a number of nodes in the network (Holl (2007) J. Transp. Geog. 15, 4). Transport nodes show a distinct hierarchy, and the importance of a transport node appears to correlate strongly with its effects on the surroundings (van den Berg and Pol (1998) Env. & Plan. C 16, 4). Factors that determine the importance of a transport node are: the situation of the transport node with respect to major metropolitan regions; the number and type of the converging transport modes; the number of destinations that can be reached from the transport node, and the frequency of the transport moves. The more important a transport node, the greater the potential regional economic development (van den Berg and Pol (1997) Eur. Reg. Sci. Assoc. 37th Eur. Congr.). See also de Langen and Visser (2005) J. Transp. Geog. 13, 2. See Devlin et al. (2008) J. Transp. Geog. 16, 1 on arc-node topology—the topological data structure ArcInfo uses to represent connectivity between arcs and nodes.

单词	node
释义	node Physics 1. (in physics) A point of minimum disturbance in a stationary-wave system. 2. (in astronomy) Either of two points at which the orbit of a celestial body intersects a reference plane, usually the plane of the ecliptic or the celestial equator (see celestial sphere). Mathematics See double point. See graph, tree. Astronomy Either of the two points at which an orbit intersects a reference plane such as the plane of the ecliptic or of the celestial equator. The line joining these points is known as the line of nodes or nodal line. At the ascending node an orbiting body moves from south to north of the reference plane; at the descending node it moves from north to south. See also regression of nodes. Statistics See network. Chemistry A point of minimal disturbance in a wave. The definition applies to the wave function of the Schrödinger equation. As the wave function for the solution of the Schrödinger equation for the hydrogen atom can be found exactly by factorizing the overall wave function into a radial part and an angular part, the existence of nodes can be demonstrated explicitly. For a principal quantum number n, the radial part has (n – 1) nodes. Thus, the higher the energy of a quantum state, the more nodes the wave function has. For a given value of n, each increase in the value of l results in an additional node in the overall wave function, meaning, in general, that for a given value of n, the energy increases as l increases. The hydrogen spectrum is an exception to this because of Fock degeneracy. Computer 1. A point in a computer network where communication lines, such as telephone lines, electric cables, or optical fibres, are interconnected. The device used to make the connection(s) may be a simple electric interface—as used in a local area network. In more complex longer-distance networks a computer is required. Node computers vary in their functional capabilities but their basic use is to switch incoming information to the necessary output line so that the information ultimately reaches its specified destination. The information may be transmitted as a whole or may be split into segments (see message switching, packet switching). When the information reaches its final destination, the node computer at this point will send it through to the recipient(s). Nodes can also be called stations, and in many X25 networks the switching nodes are known as exchanges. 2. A substructure of a hierarchical data structure that cannot be further decomposed, e.g. a vertex in a graph or tree. Internet A device attached to a network. The device could be a computer or a hardware entity such as a router or bridge. Electronics and Electrical Engineering 1. Any point, line, or surface in a distributed field at which some specified variable of a standing wave, such as voltage or current, attains a minimum value, usually zero. A partial node has a nonzero minimum. A point at which maximum magnitude is attained is an antinode. 2. (branch point) A point within an electrical network at which three or more elements are joined. See network. 3. An interconnection point in a communications network. Biology 1. (in botany) The part of a plant stem from which one or more leaves arise. The nodes at the stem apex are very close together and remain so in species of monocotyledons that form bulbs. In older regions of the stem they are separated by areas of stem called internodes. 2. (in anatomy) A natural thickening, bulge, or distinct mass of tissue in an organ or part of the body. Examples are the sinoatrial node that controls the heartbeat (see pacemaker) and the lymph nodes. 3. (in phylogenetics) (vertex) A branch point in a phylogram. Geology and Earth Sciences 1. A point of zero displacement in a material transmitting standing waves, produced by destructive interference between waves propagating in opposite directions. 2. In a phylogenetic tree, a representation of an extant (terminal node) or ancestral (internal node) operational taxonomic unit. Geography Accessibility of a node is given by the travel cost between a node and another node, or a weighted average of travel cost to a number of nodes in the network (Holl (2007) J. Transp. Geog. 15, 4). Transport nodes show a distinct hierarchy, and the importance of a transport node appears to correlate strongly with its effects on the surroundings (van den Berg and Pol (1998) Env. & Plan. C 16, 4). Factors that determine the importance of a transport node are: the situation of the transport node with respect to major metropolitan regions; the number and type of the converging transport modes; the number of destinations that can be reached from the transport node, and the frequency of the transport moves. The more important a transport node, the greater the potential regional economic development (van den Berg and Pol (1997) Eur. Reg. Sci. Assoc. 37th Eur. Congr.). See also de Langen and Visser (2005) J. Transp. Geog. 13, 2. See Devlin et al. (2008) J. Transp. Geog. 16, 1 on arc-node topology—the topological data structure ArcInfo uses to represent connectivity between arcs and nodes.
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