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951.
根据北斗一号卫星天线在轨的实际飞行温度,反推出了SR107-ZK白漆的太阳吸收比αs退化曲线,并根据该曲线外推,得到了8年寿命末期的太阳吸收比αs,预测了卫星寿命末期天线反射面的最高温度。 相似文献
952.
从新体制卫星信号的特性出发,论述新体制卫星导航信号跟踪环路的一种实现方式,即三环双估计器跟踪环路的设计方法,并以一个仿真系统为例给出各项参数推导的详细过程,最终的仿真结果证明所述方法合理可行。 相似文献
953.
954.
针对LEACH协议在能耗方面存在的不足,提出了一种分区簇头选择和簇间多跳的新协议。该协议分区域进行簇头选举、考虑了节点剩余能量、簇间采用多跳的方式传输数据。仿真结果表明,与LEACH协议相比,新协议有效的均衡了节点能耗,提高了能量利用率,延长了网络寿命。 相似文献
955.
简要介绍了末端能量管理的研究情况,然后对末端能量管理段进行轨迹规划。在轨迹规划的基础上,设计基于滑模变结构控制的制导律,对轨迹进行跟踪,对能量进行管理。仿真结果表明,滑模变结构控制在末端能量管理制导中合理、有效,具有很强的鲁棒性。 相似文献
956.
R. A. Mewaldt 《Space Science Reviews》2006,124(1-4):303-316
Recent progress in measuring the composition and energy spectra of solar energetic particles (SEPs) accelerated by CME-driven
shocks is reviewed, including a comparison of the observed charge-to-mass dependence of breaks in SEP spectra with model predictions.
Also discussed is a comparison of SEP and CME kinetic energies in seventeen large SEP events, and estimates of the SEP radiation
dose that astronauts would be subject to once they venture outside the protective cover of Earth’s magnetosphere. 相似文献
957.
This paper presents the results of finite element analysis of rubber structures based on novel strain energy functions stemming from the representation theorem of tensorial function. The stress tensor is represented by Taylor expansion, using the representation theorem of tensorial function of a single tensorial argument for all terms in each order of the expansion. The scalar-valued coefficient functions of the theorem are represented by the integrity bases of the strain tensor and material constants to be determined by experiment. The computer implementation of the new constitutive laws has been verified by comparing the FE results with analytical solutions. A complicated structure of rubber bearing was analyzed. The FE results show good correlation with experimental data. 相似文献
958.
G. P. Chernov 《Space Science Reviews》2006,127(1-4):195-326
This review covers fairly comprehensively experimental and theoretical research on the fine structure of types zebra pattern
(ZP) and fiber bursts (FB) in solar type II + IV radio bursts. The basic attention is given to the latest experimental data.
A comparative analysis of several recent solar type IV radio outbursts with these fine structure in dynamical radio spectra
is carried out using available ground-based and satellite data (Yohkoh, SOHO, TRACE, RHESSI). New data on microwave zebra
structures and fiber bursts testifies that they are analogous to similar structures observed at meter wavelengths. The discovery
of the superfine structure, in the form of millisecond spikes is the most significant new effect in the cm range. All basic
theoretical models of the zebra pattern and fiber bursts are discussed critically. Two main models are studied for their interpretation:
(i) interactions between electrostatic plasma waves and whistlers, (ii) radio emission at double plasma resonance (DPR). The
relative significance of several possible mechanisms remains uncertain. 相似文献
959.
We present a preliminary analysis of two quiet Sun transition region areas observed with the SOHO/SUMER spectrometer, using
lines from oxygen, nitrogen and silicon. The average quiet Sun physical parameters are studied as a function of line intensity.
Systematic variations of line position and width with increasing intensity are found. A large number of small-scale active
points have been observed, and preliminary analysis of the physical properties and dynamics of these active features is presented.
A jet-like structure, found in an active point, is also investigated and its velocity along the line of sight determined.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
960.
Brian E. Wood 《Space Science Reviews》2006,126(1-4):3-14
Exposure to the solar wind can have significant long term consequences for planetary atmospheres, especially for planets such
as Mars that are not protected by global magnetospheres. Estimating the effects of solar wind exposure requires knowledge
of the history of the solar wind. Much of what we know about the Sun’s past behavior is based on inferences from observations
of young solar-like stars. Stellar analogs of the weak solar wind cannot be detected directly, but the interaction regions
between these winds and the interstellar medium have been detected and used to estimate wind properties. I here review these
observations, with emphasis on what they suggest about the history of the solar wind. 相似文献