林龄单因变量的蓄积量生长模型决定系数低，引入地位指数和密度指数再次参数化的生长模型可显著提高模型拟合度。
Single age variable stock volume growth model had low coefficient of determination, but it was improved a lot by introducing site index and stand density index in reparameterization.
本文把环境温度梯度作为一个变量引入LEC法生长的理论模型中进行分析，得到了晶体中温度分布的表达式。
This paper presents an expression for temperature distribution in growing crystal by considering the ambient temperature gradient as a variable introduced in LEC model.
结果表明，立木各器官变量之间存在着很好的相对生长关系；
The results showed that there is an allometric growth relationship among the organ variables.
最后，我们还研究了一般生长曲线模型在不同可预测变量下的简单投影预测关于协方差阵的稳健性。
Finally, robustness of the simple projection predictor in the general growth curve model with different linear predictable variable on the covariance matrix are investigated.
在林分生长模型建立中，通过分析变量间的显著影响选择变量。
The variables in stand growth model were selected through analyzing the significant influences among the variables.
树木直径的实际生长年龄小于树木年龄，用树木年龄作为自变量来描述直径生长会导致生长曲线出现拐点。
Description of the tree diameter growth using tree age as independent variable may thus give an inflection point of the growth curve.
引入地位指数和密度指数可大幅提高林龄单因变量平均高生长模型的拟合度。
Repameterizing the average tree height growth model improved the fitting results a lot by introducing site index and density index variables.
实行温室控制的首要步骤是建立一个合理的数学模型，用该模型来描述温室外部变量和作物生长环境的关系。
For controlling the greenhouse environment the first step is to set up a mathematical model which describes the relationship between the external variables and the plant environment.
实行温室控制的首要步骤是建立一个合理的数学模型，用该模型来描述温室外部变量和作物生长环境的关系。
For controlling the greenhouse environment the first step is to set up a mathematical model which describes the relationship between the external variables and the plant environment.
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