关于绝对温度

绝对温度是什么意思？~

绝对温度（absolute temperature）
　　热力学温度又称开尔文温度,或称绝对温度,符号为K.绝对零度时的温度定义为0K.冰水混合物的温度为摄氏0度,定义为273.15K.水在标准大气压下结冰的温度,即摄氏温度0℃,或华氏温度32℉,相当于热力学温度273.16K 。

热力学温度又称开尔文温度，或称绝对温度，符号为K。 绝对零度时的温度定义为0K。冰水混合物的温度为摄氏0.01度，定义为273.16K。 抛开那些学术用语

The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. The Kelvin scale is a thermodynamic (absolute) temperature scale where absolute zero, the theoretical absence of all thermal energy, is zero kelvin (0 K). The Kelvin scale and the kelvin are named after the British physicist and engineer William Thomson, 1st Baron Kelvin (1824–1907), who wrote of the need for an "absolute thermometric scale". Unlike the degree Fahrenheit and degree Celsius, the kelvin is not referred to as a "degree", nor is it typeset with a degree symbol; that is, it is written K and not °K.

Contents [hide]
1 History
2 Usage conventions
2.1 Use in conjunction with Celsius
3 Color temperature
4 Kelvin as a measure of noise
5 See also
6 References
7 External links

[edit] History
See also: thermodynamic temperature#History
1848
Lord Kelvin (William Thomson), wrote in his paper, On an Absolute Thermometric Scale, of the need for a scale whereby "infinite cold" (absolute zero) was the scale’s null point, and which used the degree Celsius for its unit increment. Thomson calculated that absolute zero was equivalent to −273 °C on the air thermometers of the time.[1] This absolute scale is known today as the Kelvin thermodynamic temperature scale. It’s noteworthy that Thomson’s value of "−273" was actually derived from 0.00366, which was the accepted expansion coefficient of gas per degree Celsius relative to the ice point. The inverse of −0.00366 expressed to five significant digits is −273.22 °C which is remarkably close to the true value of −273.15 °C.
1954
Resolution 3 of the 10th CGPM gave the Kelvin scale its modern definition by designating the triple point of water as its second defining point and assigned its temperature to exactly "273.16 degrees Kelvin."[2]
1967/1968
Resolution 3 of the 13th CGPM renamed the unit increment of thermodynamic temperature "kelvin", symbol K, replacing "degree absolute", symbol °K.[3] Furthermore, feeling it useful to more explicitly define the magnitude of the unit increment, the 13th CGPM also held in Resolution 4 that "The kelvin, unit of thermodynamic temperature, is equal to the fraction 1/273.16 of the thermodynamic temperature of the triple point of water."[4]
2005
The Comité International des Poids et Mesures (CIPM), a committee of the CGPM, affirmed that for the purposes of delineating the temperature of the triple point of water, the definition of the Kelvin thermodynamic temperature scale would refer to water having an isotopic composition specified as VSMOW.[5]
[edit] Usage conventions
When reference is made to the unit kelvin (either a specific temperature or a temperature interval), kelvin is always spelled with a lowercase k unless it is the first word in a sentence.[6] When reference is made to the "Kelvin scale", the word "kelvin"—which is normally a noun—functions adjectivally to modify the noun "scale" and is capitalized.

Until the 13th General Conference on Weights and Measures (CGPM) in 1967–1968, the unit kelvin was called a "degree", the same as with the other temperature scales at the time. It was distinguished from the other scales with either the adjective suffix "Kelvin" ("degree Kelvin") or with "absolute" ("degree absolute") and its symbol was °K. The latter (degree absolute), which was the unit’s official name from 1948 until 1954, was rather ambiguous since it could also be interpreted as referring to the Rankine scale. Before the 13th CGPM, the plural form was "degrees absolute". The 13th CGPM changed the name to simply "kelvin" (symbol K).[7] The omission of "degree" indicates that it is not relative to an arbitrary reference point like the Celsius and Fahrenheit scales, but rather an absolute unit of measure which can be manipulated algebraically (e.g., multiplied by two to indicate twice the amount of "mean energy" available among elementary degrees of freedom of the system).

This SI unit is named after William Thomson, 1st Baron Kelvin. As with every SI unit whose name is derived from the proper name of a person, the first letter of its symbol is uppercase (K). When an SI unit is spelled out in English, it should always begin with a lowercase letter (kelvin), except where any word would be capitalized, such as at the beginning of a sentence or in capitalized material such as a title. Note that "degree Celsius" conforms to this rule because the "d" is lowercase.

—Based on The International System of Units, section 5.2.
The kelvin symbol is always a roman, non-italic capital K. In the SI naming convention, all symbols named after a person are capitalized; in the case of the kelvin, capitalizing also distinguishes the symbol from the SI prefix "kilo", which has the lowercase k as its symbol. The admonition against italicizing the symbol K applies to all SI unit symbols; only symbols for variables and constants (e.g., P = pressure, and c = 299,792,458 m/s) are italicized in scientific and engineering papers. As with most other SI unit symbols (angle symbols, e.g. 45° 3′ 4〃, are the exception) there is a space between the numeric value and the kelvin symbol (e.g. "99.987 K").[8][9]

Unicode provides a compatibility character for the kelvin at U+212A (decimal 8490), for compatibility with CJK encodings that provide such a character (as such, in most fonts the width is the same as for fullwidth characters).

[edit] Use in conjunction with Celsius
In science and in engineering, the Celsius scale and the kelvin are often used simultaneously in the same article (e.g., "...its measured value was 0.01028 °C with an uncertainty of 60 µK..."). This practice is permissible because the degree Celsius is a special name for the kelvin for use in expressing Celsius temperatures and the magnitude of the degree Celsius is exactly equal to that of the kelvin.[10] Notwithstanding that the official endorsement provided by Resolution 3 of the 13th CGPM states, "a temperature interval may also be expressed in degrees Celsius," the practice of simultaneously using both "°C" and "K" remains widespread throughout the scientific world as the use of SI prefixed forms of the degree Celsius (such as "µ°C" or "microdegrees Celsius") to express a temperature interval has not been widely adopted. A helpful way to think of the kelvin system is thinking that nothing can be colder than 0 kelvin (-273.15 degrees Celsius) [3]

[edit] Color temperature
Main article: Color temperature
See also: Stefan–Boltzmann constant
The kelvin is often used in the measure of the color temperature of light sources. Color temperature is based upon the principle that a black body radiator emits light whose color depends on the temperature of the radiator. Black bodies with temperatures below about 4000 K appear reddish whereas those above about 7500 K appear bluish. Color temperature is important in the fields of image projection and photography where a color temperature of approximately 5600 K is required to match "daylight" film emulsions. In astronomy, the stellar classification of stars and their place on the Hertzsprung-Russell diagram are based, in part, upon their surface temperature, known as effective temperature. The photosphere of the Sun, for instance, has an effective temperature of 5778 K.

[edit] Kelvin as a measure of noise
Main article: noise figure
In electronics, the Kelvin unit is used as an indicator of how noisy a circuit is in relation to an ultimate noise floor, i.e. the noise temperature. The so-called Johnson–Nyquist noise of discrete resistors and capacitors is a type of thermal noise derived from the Boltzmann constant and can be used to determine the noise temperature of a circuit using the Friis formulas for noise.

[edit] See also
Comparison of temperature scales
International Temperature Scale of 1990
Negative temperature
Rankine scale
Thermodynamic temperature
Triple point

(Supplement)I have the link to you, somehow Baidu is not allow to post it here.

* Don't lose sync with your promise.

绝对温度
绝对温度（absolute temperature）

热力学温度又称开尔文温度，或称绝对温度，符号为K。

绝对零度时的温度定义为0K。水的三相点，即液体、固体、气体状态的水同时存在的温度，定义为273.16K。

水在标准大气压下结冰的温度，即摄氏温度0℃，或华氏温度32℉，相当于热力学温度273.16K

参考资料：http://baike.baidu.com/view/304654.html

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安西县13221152100： 热力学温度(物理学术语) - 搜狗百科？
五桦妥布： 绝对温度的解释要先了解绝对零度的概念. 1948年国际上确定绝对零度为摄氏零下273.15度. 绝对温度就是以摄氏零下273.15度为零度的摄氏温度,单位用K表示. 摄氏零度对应的绝对温度就是273.15K 转换公式应该是: 绝对温度(K) =摄氏温度+273.15(K) 摄氏温度(℃)=绝对温度-273.15(℃)

安西县13221152100： 我们在生活中常用摄氏温度来表示物体的冷热程度,在科学研究中常用绝对温度表示物体的冷热程度,绝对温度的单位是K,绝对温度=(摄氏温度+273)K,... - ？
五桦妥布：[答案] 1.绝对温度=-38.8+273=234.7度 2.摄氏度=0-(-273)=273摄氏度

安西县13221152100： 请问何谓绝对温度? ？
五桦妥布： 绝对温度取-273.15为零度,而每度的间隔与摄氏温标相同.用绝对温标量度的温度称为绝对温度,其单位用符号K表示.

安西县13221152100： 谁能介绍下绝对温度呢? ？
五桦妥布： 温度绝对温度编辑温度绝对温标建立在卡诺循环基础上的理想而科学的温标,将水的冰点(0℃)取为273.15K(K称开尔文,绝对温标的单位),绝对温标的分度与摄氏温标相同

安西县13221152100： 绝对温度的名词解释? 要简洁但正确完整的解释. - ？
五桦妥布： 以-273.15℃为起点计算的温度(-273.15℃是最低的温度),用K来表示.

安西县13221152100： 什么叫热力学温度 什么叫绝对温度 什么叫摄氏温度 - ？
五桦妥布： 热力学温度即热力学温标,是根据卡诺热机的效率公式定义的,它的特点是和测温物质的性质无关.热力学温度又称开尔文温度,或称绝对温度,符号为K. 绝对零度时的温度定义为0K.冰水混合物的温度为摄氏0.01度,定义为273.16K. 抛开那些学术用语绝对温度(K)减去273.15.曾定义为以标准大气压力下水沸点为100℃,冰点为0℃的温度分度叫做摄氏温度

安西县13221152100： 绝对温度什么意思(自己的话说) - ？
五桦妥布： 把冰水混合状态下的温度称为零度,摄氏度为表示摄氏温度时代替开的一个专门名称.而水的三相点温度为0.01摄氏度.因此热力学温度T与人们惯用的摄氏温度t的关系是:T(K)=273.16+t(℃). 以绝对零度(0K)为最低温度,规定水的三相点的温度为 273.16K,开定义为水三相点热力学温度的1/273.16. 绝对零度是物理与化学上冷却无法再低的温度,这是宇宙的一个常数,是自然界的一个最低温度,即当温度达到负的273.16摄氏度时,就无法再冷却了,达到极限

安西县13221152100： 有没有绝对温度？
五桦妥布： 绝对温度=摄氏温度+273.15. 摄氏-275.15度为绝对零度.在这温度,所有的物质都停止运动,处于静止状态.以现在的科技,还没有找到达到该温度的方法.

安西县13221152100： 为什么绝对温度是 - 273.15摄氏度而不是别的? - ？
五桦妥布： 后来发现了温度的本质是物质的粒子无规则运动,温度差正比于粒子平均动能差,-273.15摄氏度处粒子没有任何热运动,任何物质的温度不可能低于那个温度,所以称作“绝对零度”,于是订了个新的单位“开耳文”,每一开耳文和一摄氏度的温度差一样,但开耳文的0点在绝对零度,即定义“绝对零度”为0开耳文,冰水混合物的温度 是273.15开耳文,水的沸点是373.15开耳文.