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1.
《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2020,65(11):2551-2558
The whistler-mode chorus waves are one of the most important plasma waves in the Earth’s magnetosphere. Generally, the amplitude of whistler-mode chorus waves prefers to strengthen when the energetic fluxes of anisotropic electrons increase outside the plasmapause. This characteristic is commonly associated with the geomagnetic storms or substorms. However, the relationship between the solar wind dynamic pressure (Psw) and the long-time variation of chorus waves during the quiet period of the geomagnetic activity still needs more detailed investigations. In this paper, based on MMS observations, we present a chorus event just observed in the inner side of magnetopause without obvious geomagnetic storms or substroms. Interestingly, during this time interval, some Psw fluctuations were recorded. Both the amplitudes and frequencies of chorus waves changed as a response to the variation in Psw. It proved that the enhancement of Psw increases the energetic electrons fluxes, which provides free energies for the chorus amplification. Furthermore, the wave growth rates calculated using linear theory increases and the central frequency of the chorus waves shifts to a higher frequency when the Psw enhancement is greater, which are also consistent well with the observations. The results provide a direct evidence that the Psw play an important role in the long-time variation of whistler-mode chorus waves inside the magnetopause. 相似文献
2.
《中国航空学报》2020,33(3):879-892
Detailed experimental measurements were conducted to study the interactions between incoming wakes and endwall secondary flow in a high-lift Low-Pressure Turbine (LPT) cascade. All of the measurements were conducted in both the presence and absence of incoming wakes, and numerical analysis was performed to elucidate the flow mechanism. With increasing Reynolds number, the influence of the incoming wakes on suppressing the secondary flow gradually increased owing to the greater influence of incoming wakes on reducing the negative incidence angle at higher Reynolds numbers, leading to a lower blade loading near the leading edge and suppression of the Pressure Side (PS) leg of the horseshoe vortex. However, the effect of unsteady wakes on suppressing the profile losses gradually became weaker owing to the reduced size of the Suction Side (SS) separation bubble and increased mixing loss in the free-flow region at high Reynolds numbers. Incoming wakes clearly improved the aerodynamic performance of the low-pressure turbine cascade at low Reynolds numbers of 25,000 and 50,000. In contrast, at the high Reynolds number of 100,000, the profile loss at the midspan and mass-averaged total losses downstream of the cascade were higher in the presence of wakes than in the absence of wakes, and the unsteady wakes exerted a negative influence on the aerodynamic performance of the LPT cascade. 相似文献
3.
Space Science Reviews - We discuss afresh the problem of the auroral electron acceleration based on the controversy reports of Bryant, D. A. et al.: 1992, Phys. Rev. Lett. 68, 37, and Borovsky, J.:... 相似文献
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5.
总量控制与排污权交易的理论分析 总被引:3,自引:0,他引:3
本文从总量控制与排污权交易的概念出发,论述了排污权交易的基本理论和市场机制模型,分析了总量控制与排污权交易的经济、环境和社会效益,阐述了排污权的初始分配方式及交易方式。 相似文献
6.
谢石 《华北航天工业学院学报》2005,15(5):3-6
计算机技术和通信技术的结合把计算机从传统的孤立应用推进到支持群体协同工作,从而产生了计算机支持的协同工作和多媒体电子会议系统等新型应用。本文结合本单位的实际,进行了基于Sametime电子会议协同研制工作的研究,详细论述了型号研制对电子会议系统的要求及其实现。 相似文献
7.
丁羟推进剂拉伸断裂行为的扫描电镜研究 总被引:10,自引:0,他引:10
利用扫描电镜及附属微型动态拉伸装置实验手段,对丁羟基复合固体推进剂进行了断口微观形貌观察和电镜微型拉伸试件在应变状上的断裂行为分析。结果表明,从推进剂拉伸力学行为的微观结构变化以预示其宏 同力学性能,改善丁羟推进剂粘合剂与固体颗粒之间的界面性质,是固体推进剂力学性能的一个重要方向。 相似文献
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9.
D. B. Melrose 《Space Science Reviews》1994,68(1-4):159-170
The theory of electron cyclotron maser emission and its application to solar spike bursts are reviewed. By analogy with the Earth's AKR, three sources of free energy are considered: a loss-cone anisotropy, a velocity-space hole, and a trapped distribution. The problem of how the radiation escapes through the second harmonic absorption layer is emphasized. Harmonic emission due to z mode coalescence may operate for some bursts, but the 2–5s delay between hard X-ray bursts and spike bursts suggests that some other mechanisms is required for most spike bursts. A model involving formation of a trapped distribution in low-density regions neighboring the flaring flux tube is considered. 相似文献
10.
李源生 《沈阳航空工业学院学报》1995,12(3):56-60
本文综合地运用了555集成电路,TWH9248,TWH9249雷达式扫描探测传感集成电路的SR9G26A/D、D/A转换语音存放电路等,中大规模集成电路。并利用一种简单的高频发射线路,而研制成的实用型报警装置。 相似文献