regularity conditions

A simple rule to judge the column regularity is suggested. That the retention time do not change when the column is turned round under the same temperature and pressure operating conditions can be served as the necessary and sufficient premise for a uniform column.

提出了柱均匀性的简单判据：相同柱压和温度条件下调换柱的进出口后保留时间不变是柱均匀的充分必要条件，是柱几何对称必要条件。

A physical model describing the heat and mass transfer processes of the evaporating thin film is set up and an evolution equation which shows the development regularity of dimensionless film thickness with time is obtained from the liquid vapor interfacial conditions.

论文对平面蒸发薄液膜的传热传质过程建立了物理模型，从汽液界面上的边界条件得到无量纲液膜厚度随时间变化的发展方程。

The purpose is to show that under certain conditions threshold autoregressive model can describe the random system of periodical regularity of more complicacy.

引进极限环的概念说明门限自回归模型的特性，并说明在一定条件下，门限自回归模型可以用来描述含有较复杂周期规律的随机系统。