排序方式: 共有126条查询结果,搜索用时 46 毫秒
121.
The present study focuses on the mitigation of shock wave using novel geometric passages in the flow field. The strategy is to produce multiple shock reflections and diffractions in the passage with minimum flow obstruction, which in turn is expected to reduce the shock wave strength at the target location. In the present study the interaction of a plane shock front (generated from a shock tube) with various geometric designs such as, 1) zig-zag geometric passage, 2) staggered cylindrical obstructions and 3) zig-zag passage with cylindrical obstructions have been investigated using computational technique. It is seen from the numerical simulation that, among the various designs, the maximum shock attenuation is produced by the zig-zag passage with cylindrical obstructions which is then followed by zig-zag passage and staggered cylindrical obstructions. A comprehensive investigation on the shock wave reflection and diffraction phenomena happening in the proposed complex passages have also been carried out. In the new zig-zag design, the initial shock wave undergoes shock wave reflection and diffraction process which swaps alternatively as the shock front moves from one turn to the other turn. This cyclic shock reflection and diffraction process helps in diffusing the shock wave energy with practically no obstruction to the flow field. It is found that by combining the shock attenuation ability of zig-zag passage (using shock reflection and diffraction) with the shock attenuation ability of cylindrical blocks (by flow obstruction), a drastic attenuation in shock strength can be achieved with moderate level of flow blocking. 相似文献
122.
物体表面反射光由镜面反射光和漫反射光组成,针对光滑物体表面镜面反射光和漫反射光的分离问题,建立了一个结合镜面反射和漫反射共同作用的偏振态表征模型,并使用该模型对混合反射区域偏振特征进行分析。基于镜面反射光和漫反射光的偏振特征,根据镜面反射光和漫反射光在光滑物体表面垂直方向及平行方向上的分布关系,采用偏振正交分解的方法实现了镜面反射成分和漫反射成分的求解。利用镜面反射光图像和漫反射光图像之间的相关性,通过梯度下降算法得到镜面反射成分和漫反射成分归一化互相关最小值及其对应的镜面反射偏振度和漫反射偏振度,从而实现反射光的分离。通过对不同场景中获取的反射光图像进行测试,实验结果表明,该算法具有较好的反射光分离效果。 相似文献
123.
时景秀 《中国人民武装警察部队学院学报》2009,25(9):5-9
当前,面对新的形势、新的任务和新的要求,认真分析并解决公安现役高等院校在新的历史条件下一些带有方向性、根本性的重大问题,使公安现役高等教育在更高的起点上实现全面协调可持续发展。要实现这一目标。前提条件是不断解放思想,根本要求是内涵发展,基本途径是走特色之路。 相似文献
124.
张凤艳 《兵团教育学院学报》2009,19(4):35-37
坚持不懈地用马克思主义、中国特色社会主义理论体系武装全党、教育人民,是我们在新的历史发展机遇期高扬的伟大旗帜,也是全国人民又好又快建设中国特色社会主义的共同思想基础。边疆高校必须把:中国特色社会主义理论体系教育、社会主义核心价值观教育、爱国主义教育、民族团结和发展和谐的社会主义民族观教育、民族自豪感和民族自信心教育、艰苦创业无私奉献等教育作为思想政治理论教育教学主渠道建设的核心和基本内容。 相似文献
125.
分析了斜入射角条件下F-P干涉腔的透过率特性;结合单层介质膜和单层金属膜的反射特性随入射角的变化规律,得出了反射特性参数为恒定值时微腔、低反F-P干涉腔透过率的计算误差;仿真结果表明,在光束斜入射条件下,特别是在大入射角下,单层介质膜的反射率指数增大,单层金属膜的反射率和反射相移也指数增大,但其吸收系数指数减小,造成微腔、低反F-P干涉腔透过率曲线与反射特性参数为恒定值时相比均明显向下偏移,且偏移量逐渐增大。 相似文献
126.