基于压缩感知的弹道导弹微多普勒提取方法

利用微多普勒识别弹道目标的关键是宽带雷达回波信号的微多普勒提取。宽带雷达回波信号的高速采样对硬件和算法提出了更高的要求。将压缩感知方法应用到宽带雷达回波信号的微多普勒提取中,并给出了弹道导弹目标的微多普勒计算公式和利用压缩感知重构弹道导弹微多普勒的方法。在低采样频率下利用压缩感知理论从回波信号中提取的微多普勒,与在高采样频率下利用Gabor变换提取的微多普勒是一致的,这表明利用压缩感知理论以低频率采样弹道导弹回波信号,提取微多普勒,降低工程实现难度的方法是可行的、有效的。     

使用双波带板径向剪切干涉仪检测非球面透镜

为了实现对光学非球面的低成本在线测量,在比较和分析现有非球面检测技术的基础上,设计并制作了一种小型径向剪切干涉仪用于检测非球面透镜。基于波带板可以聚焦成像的原理,该干涉仪采用不同焦距的双波带板产生径向剪切干涉。波带板由工业缩微矢量图制版技术设计和制作而成,并通过实验验证了该波带板的聚焦精度。采用傅里叶变换条纹相位分析法对干涉条纹进行处理,计算出波相差和波面面形。实验中给出了平面波光束经过一个非球面透镜后的波面面形检测结果和误差分析,使用该技术对标准非球面进行测试,波差峰谷值(P-V)达到了λ/5的精度,均方差(RMS)达到λ/10的精度。结果表明,该干涉仪具有体积小、抗干扰能力强等特点,适用于对小型非球面透镜进行在线检测。     

战术弹道导弹飞行环境中GPS卫星可用性探讨

系统地分析了在战术弹导弹飞行环境下,如何选择可用来参与弹道导弹组合制导的ＧＰＳ卫星的准则,探讨了提高弹载接收机的抗干扰能力的方法,针对战术弹道导弹标准飞行弹道,利用实测降临星历进行了仿真,给出了仿真结果。     

转叶孔板螺旋流消能的影响因素试验分析

为解决供水工程中的过剩水头问题,常在有压输水管道中配置合适的消能装置,转叶孔板螺旋流消能是一种新型的内消能方式,通过转叶孔板螺旋流消能装置的水力特性试验,可知影响转叶孔板螺旋流消能效率的主要影响因素有雷诺数Re、转叶孔板开口角度和孔板之间的相互扭转角度,还有试验装置结构的设置。根据试验数据计算分析各个影响因素对消能效率的影响。结果表明,转叶孔板螺旋流消能效率与转叶孔板之间的扭转角成正比,与雷诺数成正比,与转叶板的开口角度成反比。试验装置在进口段和出口段设置管径突变均对消能有利,该装置比与其消能原理类似的孔板消能装置更实用,且消能效率更高,对下游建筑物设施起到良好的保护作用,可推广应用。     

黑河金盆水利枢纽引水系统水力设计

黑河水库为西安市城市供水的水源地,在满足城市供水为主的任务要求外,兼顾灌溉、发电等任务。同时又与石头河供水渠道汇流,满足西安市的用水需求,因此引水系统较为繁杂。通过对引水系统水工模型试验时存在的问题的妥善解决,并采取一定的工程措施,取得了较好的运用效果。     

真空玻璃盖板热管平板式太阳能热水器的研制

介绍了研究成功的采用真空玻璃盖板的热管平板式太阳能热水器,测试了其性能,并与全玻璃真空管太阳能热水器和蜂窝热管太阳能热水器进行了比较。实测得到,真空玻璃盖板热管平板式热水器的日平均效率比后两分别大13．3％和6．5％,平均热损系数比后两分别小52．5％和21．5％。真空玻璃盖板平板式太阳能热水器性能优越,有很好的应用前景。     

Study and optimization of the thermal performances of the offset rectangular plate fin absorber plates, with various glazing

The low thermophysical characteristics of air used as a heat transfer fluid in the solar collectors with thermal conversion require a fully developed turbulent flow. This increases the thermal heat transfer between the absorber plate and the fluid, which clearly improves the thermal performances of the solar collector with obstacles arranged into the air channel duct. In the present work, we introduce, in solar collector, the offset rectangular plate fins, which are used in heat exchangers. An experimental investigation carried out showed the generated enhancement of thermal performance. The offset rectangular plate fins, mounted in staggered pattern, are oriented parallel to the fluid flow and are soldered to the underside of absorber plate. They are characterized by high heat transfer area per unit volume. High thermal performances are obtained with low pressure losses and in consequence a low electrical power consumption by the fan in comparison to the flat plate collector. The experimental results are all so compared by using two types of transparent cover; double and triple.     

带有平面反射板的全玻璃真空集热管表面能流分析

本文用解析方法对带平面反射板的单根太阳能真空集热管表面辐射流分布进行了分析，并得出了相应的结果。太阳直射辐射和散射辐射直接或通过反光板间接散布在真空管吸热体表面。为能更清楚地理解辐射的物理过程，在文中对不同辐射成分，不同反射方式分别进行了分析计算。     

平板和叉排散热器的综合换热性能分析及结构优化

本文引用无量纲品质因数F,分别对平板和叉排散热器的换热性能进行了综合分析。研究了空气流动速度、肋片排列方式以及几何尺寸对散热器综合换热性能的影响,并且以最小化F为目标函数优化了散热器。计算所得的数据有利于散热器结构的设计与改进。     

Simulation and experimental investigation of two hybrid solar domestic water heaters with drain water heat recovery

In this paper, the performance of two solar domestic hot waters (SDHW) with drain water heat recovery (DWHR) units is investigated. Both SDHW systems are recently installed at the Archetype Sustainable Twin Houses at Kortright Center, Vaughan, Ontario. The first SDWH system in House A consists of a flat plate solar thermal collector in combination with a gas boiler and a DWHR unit. The second SDHW system in House B includes an evacuated tube solar collector, an electric tank, and a DWHR unit. Both systems are modeled in TRNSYS, and the models are validated by experimental data. The addition of the DWHR and the flat‐plate solar thermal collector would result in 1831 kWh of annual energy saving in House A. While the addition of the DWHR and the evacuated tube collector in House B would result in an annual energy saving of 1771 kWh. Subsequently, the models are used to investigate the performance of similar systems for five major Canadian cities of Halifax, Montreal, Toronto, Edmonton, and Vancouver. The conjunctions of solar thermal collectors with DWHR units are found most beneficial in Edmonton. It is also noted from experimental and simulated results that flat‐plate solar collector‐based water heater produced more thermal energy than the system based on the evacuated tube solar collector for all major Canadian cities. Copyright © 2015 John Wiley & Sons, Ltd.