本文研究石油机械企业多产品生产的规划决策问题，运用系统动力学的原理建立了相应的系统模型。
This paper researches the planning and decision making problem of petroleum mechanical multiproduct enterprises, and establishes the corresponding system model by using systematic dynamic principle.
蒂森克虏伯的MULTI电梯采用的技术，与高速列车运用的磁悬浮系统原理非常相似。
The technology backing ThyssenKrupp's MULTI elevator is very similar to magnetic levitation systems used in high-speed trains.
运用变质量系统的基本原理，建立轴流脱粒过程中谷物运动的非线性动力学模型。
Based on the principle of a varied mass system, the non linear mathematical model of the crop mechanics for an axial threshing process was set up.
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