“efficiency”的概念、定义、翻译、参考文献-科学参考

efficiency

Physics

A measure of the performance of a machine, engine, etc., being the ratio of the energy or power it delivers to the energy or power fed to it. In general, the efficiency of a machine varies with the conditions under which it operates and there is usually a load at which it operates with the highest efficiency. The thermal efficiency of a heat engine is the ratio of the work done by the engine to the heat supplied by the fuel. For a reversible heat engine (see reversible process) this efficiency is equal to (T₁−T₂)/T₁, where T₁ is the thermodynamic temperature at which all the heat is taken up and T₂ is the thermodynamic temperature at which it is given out (see Carnot cycle). For real engines it is always less than this.

Mathematics

See machine.

Statistics

See estimator.

Chemistry

A measure of the performance of a machine, engine, etc., being the ratio of the energy or power it delivers to the energy or power fed to it. In general, the efficiency of a machine varies with the conditions under which it operates and there is usually a load at which it operates with the highest efficiency. The thermal efficiency of a heat engine is the ratio of the work done by the engine to the heat supplied by the fuel. For a reversible heat engine this efficiency equals (T₁ – T₂)/T₁, where T₁ is the thermodynamic temperature at which all the heat is taken up and T₂ is the thermodynamic temperature at which it is given out (see Carnot cycle). For real engines it is always less than this.

Chemical Engineering

A measure of the effectiveness of a machine or process expressed as a ratio of the energy or power output or delivered to the energy or power supplied. For example, the efficiency of a compressor is the ratio of the energy consumed in isoentropic compression to the actual power consumption.

Electronics and Electrical Engineering

The relationship between the benefit obtained from a device and the effort required to get that benefit. The most common example is energy efficiency, but other comparisons are also possible. For example, of interest in power distribution is the comparison of the capital cost of the transmission line to the cost of the electrical power lost in that line over its expected life.

Geography

The ratio of the work done to the effort used; usually the relation of output to input. Spatial efficiency—the organization of space in order to minimize costs—is central to location theory; see Borrás and Pastor (1998) Location Sci. 6, 1–4.

Economics

Obtaining the maximum output for given inputs. Efficiency in consumption means allocating goods between consumers so that it would not be possible by any reallocation to make some people better off without making anybody else worse off. Efficiency in production means allocating the available resources between industries so that it would not be possible to produce more of some goods without producing less of any others. Efficiency in the choice of goods to produce means choosing so that it would not be possible to change the set of goods so as to make some consumers better off without others becoming worse off. The concept of Pareto efficiency is used as a test of efficiency for an economic allocation. See also technical efficiency; X-efficiency.

单词	efficiency
释义	efficiency Physics A measure of the performance of a machine, engine, etc., being the ratio of the energy or power it delivers to the energy or power fed to it. In general, the efficiency of a machine varies with the conditions under which it operates and there is usually a load at which it operates with the highest efficiency. The thermal efficiency of a heat engine is the ratio of the work done by the engine to the heat supplied by the fuel. For a reversible heat engine (see reversible process) this efficiency is equal to (T₁−T₂)/T₁, where T₁ is the thermodynamic temperature at which all the heat is taken up and T₂ is the thermodynamic temperature at which it is given out (see Carnot cycle). For real engines it is always less than this. Mathematics See machine. Statistics See estimator. Chemistry A measure of the performance of a machine, engine, etc., being the ratio of the energy or power it delivers to the energy or power fed to it. In general, the efficiency of a machine varies with the conditions under which it operates and there is usually a load at which it operates with the highest efficiency. The thermal efficiency of a heat engine is the ratio of the work done by the engine to the heat supplied by the fuel. For a reversible heat engine this efficiency equals (T₁ – T₂)/T₁, where T₁ is the thermodynamic temperature at which all the heat is taken up and T₂ is the thermodynamic temperature at which it is given out (see Carnot cycle). For real engines it is always less than this. Chemical Engineering A measure of the effectiveness of a machine or process expressed as a ratio of the energy or power output or delivered to the energy or power supplied. For example, the efficiency of a compressor is the ratio of the energy consumed in isoentropic compression to the actual power consumption. Electronics and Electrical Engineering The relationship between the benefit obtained from a device and the effort required to get that benefit. The most common example is energy efficiency, but other comparisons are also possible. For example, of interest in power distribution is the comparison of the capital cost of the transmission line to the cost of the electrical power lost in that line over its expected life. Geography The ratio of the work done to the effort used; usually the relation of output to input. Spatial efficiency—the organization of space in order to minimize costs—is central to location theory; see Borrás and Pastor (1998) Location Sci. 6, 1–4. Economics Obtaining the maximum output for given inputs. Efficiency in consumption means allocating goods between consumers so that it would not be possible by any reallocation to make some people better off without making anybody else worse off. Efficiency in production means allocating the available resources between industries so that it would not be possible to produce more of some goods without producing less of any others. Efficiency in the choice of goods to produce means choosing so that it would not be possible to change the set of goods so as to make some consumers better off without others becoming worse off. The concept of Pareto efficiency is used as a test of efficiency for an economic allocation. See also technical efficiency; X-efficiency.
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