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采用球－三盘磨损试验机在３７０℃，聚乙烯醇及磷酸三甲苯基酯气相润滑下研究了Ｓｉ３Ｎ４与Ｍ５０工具钢对磨时的磨损特性．结果表明：在气相润滑下聚乙烯醇可以有效地降低Ｓｉ３Ｎ４的磨损；在聚乙烯醇中添加少量的三甲苯基磷酸酯可以进一步降低Ｓｉ３Ｎ４的磨损．Ｘ射线光电子能谱分析发现，Ｓｉ３Ｎ４的摩擦表面形成了主要由元素碳、氧和磷组成的固体润滑膜，Ｓｉ３Ｎ４发生了氧化并生成了ＳｉＯ２和—ＳｉＮＯ等化合物，而三甲苯基磷酸酯则在摩擦过程中发生了降解．

关键词：气相润滑氮化硅陶瓷聚乙烯醇碳酸三甲苯基酯

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Separable Space-Time Pattern Synthesis for SBR Sparse Aperture Array GMTI

Separable Space-Time Pattern Synthesis for SBR Sparse Apertu...

引用

2007 Asian and Pacific Conference on Synthetic Aperture Radar(APSAR 2007)

作者： Long Zhuang and Xingzhao Liu ee Department of Shanghai Jiaotong University Shanghai China

In this paper,a novel GMTI method is proposed for spaceborne sparse aperture radar using separable space-time processing. The extremely long baseline of a sparse aperture array can provide a narrow main beam at he cost of large number of grating lobes. To suppress ground clutter caused by grating lobes,a Doppler filter is applied at the output of the sparse array. An efficient,yet robust projection method is used to solve the Doppler filter coefficients,which is an ill-posed problem. More than -30 dB substantial gains can be achieved after sparse array beamforming and Doppler filtering.

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