在动态子结构修改方法的基础上，建立了车身结构的低噪声优化设计模型。

An optimization model for low noise design of an automobile body structure is developed based on the dynamic substructure modification method.

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本文根据海洋噪声场随机局部谱展开理论，分析了典型浅海负梯度(或负跃层)下低噪声信道的理论模型。

Based on the theory of the local spectrum of ambient-sea noise field, theoretical models of the low-noise-channel for typical shallow-water negative gradient (or thermocline) are developed.

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建立了漏斗型MCP的数学模型，给出了降低MCP的噪声因子及提高电流增益的理论依据，为低噪声mcp进一步的工艺研究打下了基础。

A mathematic model of funnel MCP is built. The theoretical evidence of reducing noise figure and improving the current gain is given. It will provide a theory foundation for further craft research.

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