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751.
卫星正常运行要求星载子网的数据传输管理需具备可靠性、安全性与实时性,能够在规定的时间内完成传输任务,因此需要设计一种合理的数据传输管理方案来满足要求。考虑到1553B总线的数据传输具备速率高、可靠性好和实时性强等优点,选取1553B总线作为星载子网的数据总线,并提出了一种适用的数据传输管理方案。方案合理设计了星载子网的消息结构、消息种类、组网方式、消息传输机制、消息传输流程、消息传输时隙等。最后通过搭建测试平台对传输管理方案进行测试,测试结果表明此方案传输速率高、误码率低、实时性强,可以满足要求。 相似文献
752.
P.K. Subhadra Devi K. Unnikrishnan 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
In this study, 30 storm sudden commencement (SSC) events during the period 2001–2007 for which daytime vertical E × B drift velocities from JULIA radar, Jicamarca (geographic latitude 11.91°S, geographic longitude 283.11°E, 0.81°N dip latitude), Peru and ΔH component of geomagnetic field measured as the difference between the magnitudes of the horizontal (H) components between two magnetometers deployed at two different locations Jicamarca (geographic latitude 11.91°S, geographic longitude 283.11°E, 0.81°N dip latitude) and Piura (geographic latitude 5.21°S, geographic longitude 279.41°E, 6.81°N dip latitude), in Peru, were considered. It is observed that a positive correlation exists between peak value of daytime vertical E × B drift velocity and peak value of ΔH for the three consecutive days of SSC. A qualitative analysis made after selecting the peak values of daytime vertical E × B drift velocity and ΔH showed that 57% of the events have daytime vertical E × B drift velocity peak in the magnitude range 20–30 m/s and 63% of the events have ΔH peak in the range 80–100 nT. The maximum probable (45%) range of time of occurrence of peak value for both vertical E × B drift velocity and ΔH during the daytime hours were found to be the same, i.e., 10:00–12:00 LT. A strong positive correlation was also found to exist between the daytime vertical E × B drift velocity and ΔH for all the three consecutive days of SSC, for all the events considered. To establish a quantitative relationship between day time vertical E × B drift velocity and ΔH, linear and polynomial (order 2 and 3) regression analysis (Least Square Method (LSM)) were carried out, considering the fully disturbed day after the commencement of the storm as ‘disturbed period’ for the SSC events selected for analysis. The formulae indicating the relationship between daytime vertical E × B drift velocity and ΔH, for the ‘disturbed periods’, obtained through the regression analysis were verified using the JULIA radar observed E × B drift velocity for 3 selected events. Root Mean Square (RMS) error analysis carried out for each case suggest that polynomial regression (order 3) analysis provides a better agreement with the observations from among the linear, polynomial (order 2 and 3) analysis. 相似文献
753.
Jinlu Hu Liang Jin Xiaojuan Wang Wenkai Cai Yongding Liu Gaohong Wang 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
The present study investigated the physiological and biochemical characteristics of Scytonema javanicum, a pioneer species isolated from desert biological crusts, under salinity stress. Pigment analysis showed that salinity decreased chlorophyll a and phycocyanin content, while low salinity increased carotenoid concentration and high salinity decreased carotenoid concentration. Salinity also inhibited CO2 assimilation rate and photosynthetic oxygen evolution in this cyanobacterium. Chlorophyll a fluorescence transient parameters (φPo, φEo, ψO, RC/ABS, RC/CS, PIABS, and PICS) were decreased under salt stress, while dVo/dto(Mo), Vj and φDo were increased. The decrease of ETRmax and Yield and the change of chlorophyll a fluorescence transients showed that salt stress had an important influence on photosynthesis. These results indicated that the effects of salinity stress on photosynthesis in S. javanicum may depend on the inhibition of electron transport and the inactivation of the reaction centers, but this inhibition may occur in the electron transport pathway at the PSII donor and acceptor sites. 相似文献
754.
在高职院校,普遍存在着辅导员学习研究意识淡漠,缺乏学科背景支持、学习氛围不浓等问题,针对这些问题,高职院校须构建一支学习型辅导员队伍,可采取的具体策略包括:建设学习型学生工作领导队伍、培养问题研究意识、加强团队学习和培训指导等策略。 相似文献
755.
依据高职院校新生报到管理的工作要求,讨论以B/S架构为基础架构,使用Microsoft Visual studio2010作为前端开发工具,以SQL Server 2008作为后台数据库的新生报到管理系统的设计与实现。 相似文献
756.
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758.
自动化测试系统在环境减灾-1A、1B卫星中的应用 总被引:1,自引:1,他引:0
在环境减灾-1A、1B(HJ-1A、1B)卫星的研制中,双星并行电性能综合测试是一个非常复杂和细致的过程,为此应用了卫星自动化测试系统,实现了测试信息的集中管理、测试数据的综合利用和测试流程的自动化,提高了测试工作的效率和质量。文章介绍HJ-1A、1B双星并行自动化综合测试系统,主要阐述测试实时数据库、自动化测试控制台、参数自动化监视软件等。 相似文献
759.
Operation and Application of A, B Satellites for Environment and Disaster Monitoring and Forecasting
Wang Jianyu Liu Yinnian Fang Zhiyon Yang Siquan Nie Juan Wu Wei Liu Sanchao Wang Lei Wang Qiao Wei Bin Wang Changzuo Zhang Feng Yu Jin Li Zhaozhou 《空间科学学报》2010,30(5):486-492
Environment and disaster monitoring and forecasting small satellite constellation A and B satellites (HJ-1-A, B) are called "environment and disaster reduction satellites A and B' for short. The constellation adopts a 10:30 LT sun-synchronous circular orbit, with orbit altitude of 649 km. HJ-1-A and HJ-1-B are distributed with a phase difference of 180o in the same orbital plane, so as to enhance the time resolution of earth observation. The satellites have orbit maintenance capability, the lifetime is 3 years. Both satellites adopt CAST968 platforms. Two wide-coverage multispectral CCD cameras with resolution 30 m and width 700 km, a super-spectral imager with resolution 100 m and width 50 km as well as a data transmission subsystem of 120 Mbit/s are deployed on HJ-1-A, which also carries Ka communication testing equipment of Thailand. HJ-1-B has two wide-coverage multispectral CCD cameras (the same as satellite A), one infrared camera with resolution 150 m and width 720 km and a data transmission subsystem of 60 Mbit/s. The coverage period of the wide-coverage multispectral CCD camera is 48 hours. The revisit period of super-spectral imager is 96 hours and the coverage period of infrared camera is 96 hours. 相似文献
760.
针对某型便携式导弹,研究了其初始段侧向推力与空气动力的复合控制。首先介绍了自旋导弹控制力产生机理,建立了引入侧向推力后的动力学模型,设计了相应的控制方法,并对其进行了仿真。仿真结果表明引入侧向推力后的控制效果与加前置量的效果相近,可以达到直瞒的目的。 相似文献