变势能阱双稳态气动弹性能量收集的性能增强研究

提出一种新型的磁耦合变势能阱双稳态压电颤振能量收集器，设计了外部磁场作用下颤振能量收集系统的双稳态构型，并利用弹性支撑的外部磁铁的运动实现了变势能阱技术，解释了变势能阱双稳态对颤振能量收集系统的性能增强机理。建立了磁力-压电-气动弹性耦合的颤振能量收集系统的动力学分析模型，根据非线性磁偶极模型以及平衡点稳定性理论，讨论了系统出现双稳态构型的参数条件。对磁耦合双稳态颤振能量收集系统的动态特性进行了数值仿真研究，结果显示，双稳态构型能够使无磁力颤振能量收集系统的超临界颤振行为转变为亚临界颤振，发生极限环振动的风速能够降低50%以上，拓宽了能量收集器的有效工作风速范围，并分析了磁铁间距、磁偶极矩对能量收集性能的影响规律。采用弹性支撑的外部磁铁的运动来自适应调节内外部磁铁之间的距离，达到变势能阱的目的，有效地降低了双稳态的势能阱深度，使系统更容易发生双稳态势能阱间的跃迁运动，从而在双稳态的设计基础上，实现了能量收集工作风速范围和输出电功率的同步提升，为低风速下的能量收集提供了一种有效的设计途径。     

太阳能飞机循环飞行的高度剖面能量策略

为满足设定的太阳能飞机多日连续飞行条件，依据飞行过程中当前时刻的飞行高度、光伏输出功率、动力电池组余量等系统状态参数，研究如何分配动力电池组充放电和电推进系统输入等功率。所用策略立足于实时功率平衡，充分利用正午前后的光伏峰值功率用于飞机爬升及充电，在午后下滑过程中利用全部光伏输出，以最大化利用光伏资源；在光伏有效输出不足时则以一定的维持功率下滑，使能量的综合损失最小。方法能够提高以预定夜间飞行高度连续多日续航的成功率，提升飞行高度、纬度、季节范围或搭载能力，或者拓展这几种飞行条件的组合域，优化太阳能飞机的适用性。     

A robust object-based shadow detection method for cloud-free high resolution satellite images over urban areas and water bodies

Unwanted contrast in high resolution satellite images such as shadow areas directly affects the result of further processing in urban remote sensing images. Detecting and finding the precise position of shadows is critical in different remote sensing processing chains such as change detection, image classification and digital elevation model generation from stereo images. The spectral similarity between shadow areas, water bodies, and some dark asphalt roads makes the development of robust shadow detection algorithms challenging. In addition, most of the existing methods work on pixel-level and neglect the contextual information contained in neighboring pixels. In this paper, a new object-based shadow detection framework is introduced. In the proposed method a pixel-level shadow mask is built by extending established thresholding methods with a new C₄ index which enables to solve the ambiguity of shadow and water bodies. Then the pixel-based results are further processed in an object-based majority analysis to detect the final shadow objects. Four different high resolution satellite images are used to validate this new approach. The result shows the superiority of the proposed method over some state-of-the-art shadow detection method with an average of 96% in F-measure.     

流动阻力及能量损失对注射成型制件的影响

本文分析了在塑料熔体充满型腔的过程中，流动阻力及能量损失产生的形式和物理原因，进而讨论了对塑料制件成型及凝固过程中的影响。并提出降低影响的措施。     

Space Astronomy in China:2002-2004

More and more proposals, or potential projects have been proposed in recent two years. We try to briefly outline these new proposals, although most of them are in fact only in their conception studies. The progress of previously mentioned projects, like Space Solar Telescope (SST), the Hard X-ray Modulation Telescope (HXMT), as well as newly initiated LUnar Resource Explorer (LUREX), will be introduced elsewhere.     

高频大电压标准器

主要阐述了该标准器的基本原理,从理论上对结构补偿法进行了分析和数学推导,当R/Z_o=1.9～2.0之间时,具有最小的交直流差。设计了匹配的同轴热电转换标准器;进行了误差分析;给出了试验结果,说明该标准器交直流差的重复性和复现性是好的。     

Water Cherenkov detectors:MILAGRO

This paper discusses the properties of using the water Cherenkov technique to detect air showers in the few hundred GeV to 100 TeV energy range. The responses of a 6 m² 2 m deep water Cherenkov counter and that of a 6 m² 10cm thick scintillator-lead sandwich counter to air shower electrons and photons is described. The advantages of water Cherenkov detector is outlined. Its application to do VHE gamma ray astronomy is discussed with particular reference to the MILAGRO telescope currently under construction. Milagro, a water-Cherenkov detector to do gamma ray astronomy above 100 Gev, uses an existing pool 60m × 80m by 8m, located in the Jemez mountains near Los Alamos, NM. The threshold of the MILAGRO detector is comparable to atmospheric Cherenkov detectors, however it has several advantages over these optical detectors. MILAGRO can operate 24 hours a day in all weather conditions and it has an open aperture which allows it to view the entire northern sky every day. These capabilities allow for a systematic all-sky survey to be done for the first time at these energies. MILAGRO will measure the Crab spectrum with high significance over a wide energy range, it will detect and measure the spectra from AGN's such as MRK 421 and it will search for short duration bursts from GRBs and possibly evaporating PBHs.     

新建他激反激变换器方程及其解析解

引用文 [1 ]的思路 ,寻找他激反激变换器的运行状态特征参量 (磁通密度增量、剩余磁通密度和占空比 )与构成这一变换器的基本物理参量之间的函数关系。首先阐明由于频率给定 ,他激反激变换器稳态运行时会出现无剩磁工况和有剩磁工况两种。而后确定这两种工况下 ,磁路等效储能空间单位体积每个周期的传输能量 (命名为“磁能传输密度”)。在这基础上 ,分别建立和解出他激反激变换器在不同工况下稳定运行时应满足的方程。最后根据所得的解析解阐明这种变换器的特性。本文和文 [1 ],以磁路分析为基础建立了一种新的反激变换器理论。     

用于高压动态校准的快开阀装置

介绍一种高压快开阀装置。它可产生３７０ＭＰａ上升时间小于２０μｓ的阶跃压力，用于对高压传感器进行动态校准。     

空间能量粒子探测方法研究

阐述了空间能量粒子探测的原理和方法。介绍了国外在能量粒子探测方面所采用的半导体望远镜测量法、电场加速法、磁偏转法等方法，分析了它们各自的优缺点。就制约能量粒子探测技术发展的关键因素进行了讨论。并以此为基础，结合我国实际情况提出了一种新的探测方法。