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第75行： − + − 《数学》+ − + − + − + − \begin{align}+ − + − 开始{ align }+ − + − is the number of molecules which ''all'' have positions lying within a volume element <math> d^3\bf{r}</math> about '''r''' and momenta lying within a [[momentum space]] element <math> \mathrm{d}^3\bf{p}</math> about '''p''', at time ''t''.<ref>{{Cite book |last=Huang |first=Kerson |year=1987 |title=Statistical Mechanics |url=https://archive.org/details/statisticalmecha00huan_475 |url-access=limited |location=New York |publisher=Wiley |isbn=978-0-471-81518-1 |page=[https://archive.org/details/statisticalmecha00huan_475/page/n65 53] |edition=Second }}</ref> [[Integration (calculus)|Integrating]] over a region of position space and momentum space gives the total number of particles which have positions and momenta in that region:+
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The equation arises not by analyzing the individual positions and momenta of each particle in the fluid but rather by considering a probability distribution for the position and momentum of a typical particle—that is, the probability that the particle occupies a given very small region of space (mathematically the volume element <math>\mathrm{d}^3 \bf{r}</math>) centered at the position <math>\bf{r}</math>, and has momentum nearly equal to a given momentum vector <math> \bf{p}</math> (thus occupying a very small region of momentum space <math>\mathrm{d}^3 \bf{p}</math>), at an instant of time.
The equation arises not by analyzing the individual positions and momenta of each particle in the fluid but rather by considering a probability distribution for the position and momentum of a typical particle—that is, the probability that the particle occupies a given very small region of space (mathematically the volume element <math>\mathrm{d}^3 \bf{r}</math>) centered at the position <math>\bf{r}</math>, and has momentum nearly equal to a given momentum vector <math> \bf{p}</math> (thus occupying a very small region of momentum space <math>\mathrm{d}^3 \bf{p}</math>), at an instant of time.
玻尔兹曼方程并不分析流体中每个粒子的单个位置和动量，而是着重考虑一个典型粒子的位置和动量的概率分布，也就是粒子在某一时刻占据给定很小空间区域
方程的导出不是通过分析流体中每个粒子的单独位置和动量，而是通过考虑一个典型粒子的位置和动量的概率分布——即粒子某一时刻位于给定位置的小邻域（数学上的体积元<math>\mathrm{d}^3 \bf{r}</math>）、在动量空间占据给定动量矢量<math> \bf{p}</math>的小邻域（<math>\mathrm{d}^3 \bf{p}</math>）的概率。一个给定的非常小的空间区域的概率(数学上是体积元素 < math > mathrm { d } ^ 3 bf { r } </math >) ，动量几乎等于给定的动量矢量 < math > (因此在瞬间占据了一个非常小的动量空间 mathrm { d }3 bf/math >)。
方程的导出不是通过分析流体中每个粒子的单独位置和动量，而是通过考虑一个典型粒子的位置和动量的概率分布——即粒子某一时刻位于给定位置的小邻域（数学上的体积元<math>\mathrm{d}^3 \bf{r}</math>）、在动量空间占据给定动量矢量<math> \bf{p}</math>的小邻域（<math>\mathrm{d}^3 \bf{p}</math>）的概率。一个给定的非常小的空间区域的概率(数学上是体积元素 < math > mathrm { d } ^ 3 bf { r } </math >) ，动量几乎等于给定的动量矢量 < math > (因此在瞬间占据了一个非常小的动量空间 mathrm { d }3 bf/math >)。
The equation arises not by analyzing the individual [[position vector|position]]s and [[momentum|momenta]] of each particle in the fluid but rather by considering a probability distribution for the position and momentum of a typical particle—that is, the [[probability]] that the particle occupies a given [[infinitesimal|very small]] region of space (mathematically the [[volume element]] <math>\mathrm{d}^3 \bf{r}</math>) centered at the position <math>\bf{r}</math>, and has momentum nearly equal to a given momentum vector <math> \bf{p}</math> (thus occupying a very small region of [[momentum space]] <math>\mathrm{d}^3 \bf{p}</math>), at an instant of time.
The equation arises not by analyzing the individual [[position vector|position]]s and [[momentum|momenta]] of each particle in the fluid but rather by considering a probability distribution for the position and momentum of a typical particle—that is, the [[probability]] that the particle occupies a given [[infinitesimal|very small]] region of space (mathematically the [[volume element]] <math>\mathrm{d}^3 \bf{r}</math>) centered at the position <math>\bf{r}</math>, and has momentum nearly equal to a given momentum vector <math> \bf{p}</math> (thus occupying a very small region of [[momentum space]] <math>\mathrm{d}^3 \bf{p}</math>), at an instant of time.
The Boltzmann equation can be used to determine how physical quantities change, such as heat energy and momentum, when a fluid is in transport. One may also derive other properties characteristic to fluids such as viscosity, thermal conductivity, and electrical conductivity (by treating the charge carriers in a material as a gas).
The Boltzmann equation can be used to determine how physical quantities change, such as heat energy and momentum, when a fluid is in transport. One may also derive other properties characteristic to fluids such as viscosity, thermal conductivity, and electrical conductivity (by treating the charge carriers in a material as a gas).
<math>
<math>
《数学》
\begin{align}
开始{ align }
is the number of molecules which ''all'' have positions lying within a volume element <math> d^3\bf{r}</math> about '''r''' and momenta lying within a [[momentum space]] element <math> \mathrm{d}^3\bf{p}</math> about '''p''', at time ''t''.<ref>{{Cite book |last=Huang |first=Kerson |year=1987 |title=Statistical Mechanics |url=https://archive.org/details/statisticalmecha00huan_475 |url-access=limited |location=New York |publisher=Wiley |isbn=978-0-471-81518-1 |page=[https://archive.org/details/statisticalmecha00huan_475/page/n65 53] |edition=Second }}</ref> [[Integration (calculus)|Integrating]] over a region of position space and momentum space gives the total number of particles which have positions and momenta in that region:
N & = \int\limits_\mathrm{momenta} \text{d}^3\mathbf{p} \int\limits_\mathrm{positions} \text{d}^3\mathbf{r}\,f (\mathbf{r},\mathbf{p},t) \\[5pt]
N & = \int\limits_\mathrm{momenta} \text{d}^3\mathbf{p} \int\limits_\mathrm{positions} \text{d}^3\mathbf{r}\,f (\mathbf{r},\mathbf{p},t) \\[5pt]