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891.
Y. Yan J. Huang B. Chen Y. Liu C. Tan 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
Radio bursts with fine structures in decimetric–centimetric wave range are generally believed to manifest the primary energy release process during flare/CME events. By spectropolarimeters in 1–2 GHz, 2.6–3.8 GHz, and 5.2–7.6 GHz at NAOC/Huairou with very high temporal (1.25–8 ms) and spectral (4–20 MHz) resolutions, the zebra patterns, spikes, and new types of radio fine structures with mixed frequency drift features are observed during several significant flare/CME events. In this paper we will discuss the occurrence of radio fine structures during the impulsive phase of flares and/or CME initiations, which may be connected to the magnetic reconnection processes. 相似文献
892.
本文提出了一种适用于推挽线路的IGBT低损耗吸收回路,分析了该电路的工作原理。进行了能量损耗地计算,并与传统电路进行了比较,提供了实验数据。 相似文献
893.
Zhaoqiang Bi Jian Li Zheng-She Liu 《IEEE transactions on aerospace and electronic systems》1999,35(1):267-281
Super resolution synthetic aperture radar (SAR) image formation via sophisticated parametric spectral estimation algorithms is considered. Parametric spectral estimation methods are devised based on parametric data models and are used to estimate the model parameters. Since SAR images rather than model parameters are often used in SAR applications, we use the parameter estimates obtained with the parametric methods to simulate data matrices of large dimensions and then use the fast Fourier transform (FFT) methods on them to generate SAR images with super resolution. Experimental examples using the MSTAR and Environmental Research Institute of Michigan (ERIM) data illustrate that robust spectral estimation algorithms can generate SAR images of higher resolution than the conventional FFT methods and enhance the dominant target features 相似文献
894.
Shun Liu Hagiwara H. Shoji R. Tamara H. Okano T. 《Aerospace and Electronic Systems Magazine, IEEE》2004,19(11):3-11
A complete grasp of the actual vessel traffic flow by accurate observation is essential to carry out vessel traffic management, design of vessel traffic route, plan of port construction, etc. Up to now, the observation of vessel traffic has needed many efforts such as the use of a special ship or car equipped with radar observation systems and the observation staff preparation for a considerably long period. In order to perform accurate observation of vessel traffic without such efforts, the authors have developed a completely automated radar network system covering the main traffic route of Tokyo Bay. In August 2003, as the second remote radar station attaching AIS equipment was set at East Ogishima (the first was installed at the National Defense Academy in 2002), the observing range could be enlarged and cover most traffic routes in Tokyo Bay. These two radars can observe the vessel traffic in Tokyo Bay simultaneously so as to know the traffic flow accurately on the basis of analyzing the integrated radar data. In addition to the development of a radar network system, the software to analyze observed vessel traffic flow has been developed. This software has various functions such as tracking of ship's position, automatic determination of ship's size, animation of ship's movements, superposition of successive radar images, display of ship's tracks, calculation of ship's speed distribution, extraction of dangerous ship encounters using subjective judgment value and bumper model, etc. Some analyzed results on vessel traffic flow observed by the remote radars in January and September 2003 are shown in this paper. 相似文献
895.
896.
本文介绍了配料生产过程中单片机控制系统的硬件结构及软件流程。由于硬件和软件设计上都采用了模块化的结构,所以便于安装调试,整个系统可推广到诸如水泥、矿产、食品加工等生产中。 相似文献
897.
Grasping Strategy in Space Robot Capturing Floating Target 总被引:3,自引:3,他引:0
When the space robot captures a floating target, contact impact occurs inevitably and frequently between the manipulator hand and the target, which seriously impacts the position and attitude of the robot and grasping security. “Dynamic grasping area” is introduced to describe the collision process of manipulator grasping target, and grasping area control equation is established. By analyzing the impact of grasping control parameters, base and target mass on the grasping process and combining the life experience, it is found that if the product of speed control parameter and dB adjustment parameter is close to but smaller than the minimum grasping speed, collision impact in the grasping process could be reduced greatly, and then an ideal grasping strategy is proposed. Simulation results indicate that during the same period, the strategy grasping is superior to the accelerating grasping, in that the amplitude of impact force is reduced to 20%, and the attitude control torque is reduced to 15%, and the impact on the robot is eliminated significantly. The results would have important academic value and engineering significance. 相似文献
898.
介绍一种以线性调频半导体激光为光源的衍射光栅干涉仪。激光与光栅上衍射的±1级衍射波会合,由于有光程差而发生光拍频,测量拍频信号的相位移则可测得光栅的位移。设计了一种克服激光波长漂移和空气折射率变化影响的对称差动光路,使这种方法达到实用化的程度,分辨力达到纳米级。此外,还介绍了应用于接触干涉仪的实验情况。 相似文献
899.
刘奎 《南京航空航天大学学报》1998,30(3):300-305
首次提出了在烧结型金刚石工具的制造中引入热处理的新工艺,并系统地研究了淬火温度、淬火时间及回火温度等热处理工艺参数对热压烧结型铁基金刚石圆盘锯节块及其胎体材料机械性能的影响,同时对经热处理的铁基金刚石圆盘锯节块在石材旺苍红上进行磨损试验研究。试验结果表明,热压烧结型铁基金刚石圆盘锯节块胎体热处理的最佳工艺参数为:淬火温度为760~790℃、淬火时间为3.5min、回火温度为245~315℃;经热处理后铁基金刚石圆盘锯胎体及节块的强度、硬度等机械性能有显著的提高,热处理也能明显改善铁基金刚石圆盘锯节块的耐磨性能。这说明将热处理工艺用于烧结型金刚石工具的制造中是切实可行的。 相似文献
900.
Both the Capon and APES estimators can be shown to belong to the class of matched-filterbank spectral estimators and can be used to obtain complex spectral estimates that have more narrow spectral peaks and lower sidelobe levels than the fast Fourier transform (FFT) methods. It can also be shown that APES has better statistical performance than Capon. In this paper, we address the issue of how to efficiently implement Capon and APES for spectral estimation 相似文献