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151.
V.V. Mishin V.M. Mishin Z. Pu S.B. Lunyushkin L.A. Sapronova U. Sukhbaatar D.G. Baishev 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
The magnetic flux of tail lobes Ψ is divided in two parts of comparable values Ψ1 and Ψ02, with the first that appears during substorm and the second, observed before substorm start. The first was named “new magnetic flux”, the second – “old magnetic flux”. The first, Ψ1, is known to play a definitive role in the energy transport from the solar wind into the magnetosphere-ionosphere-atmosphere system, but the role of Ψ02 in this transport is not well known. From the 27 August 2001 substorm data we study the involvement in the above transport process of the old flux Ψ02. This involvement is observed in the polar cap (PC) area, which existed prior to the substorm and is called respectively “the old PC”. In this study, as distinct from earlier works, we use the balance equation of the energy stored in magnetosphere and energy consumed. Activation of the old PC magnetic flux Ψ02 was found to increase the energy input by ∼85% in the event under consideration. 相似文献
152.
A. Devdariani 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
The review is aimed at the discussion of recent results on spectral profiles produced in collisions of few-electron atoms/ions. Calculations of spectral profiles produced by atom/ion collisions need some preliminary quantum-chemical information such as potential energy surfaces, dipole transition moments, etc. The main advantage of few-electron systems is that all input data can be obtained ab initio or analytically, thus the profiles calculated do not include any fit parameters. Two specific examples have been discussed. The first one deals with radiative transitions accompanying charge-exchange in collisions of one-electron ions with bare nuclei. The second example concerns radiative transitions produced by H− + H collisions. 相似文献
153.
针对反作用飞轮电机换相所产生的非理想力矩影响卫星姿态控制精度的问题,采用永磁无刷直流电机绕组感生电势、相电流和电磁转矩的解析计算方法得到了反作用飞轮电机的换相力矩波动最小化条件,提出了基于该最小化条件的换相力矩波动抑制高动态协同控制方法,抑制反作用飞轮电机三种运行状态下的换相力矩波动.试验结果表明,电动状态下换相力矩波动减小了12%、可控能耗制动和反接制动状态下换相力矩波动减小了90%以上,验证了该方法的可行性和有效性. 相似文献
154.
《中国航空学报》2022,35(9):71-80
With the development of Unmanned Aerial Vehicles (UAVs), the applications of UAVs have been extensively explored. In the field of wireless communications, the relay nodes are often used to extend network coverage. However, traditional fixed ground relays cannot be flexibly deployed due to their low heights and fixed locations. Hence, deploying UAV as relay node is a promising solution and has become a research hotspot. In this paper, we consider an UAV-enabled relaying network in which a fixed-wing UAV is deployed between the Base Station (BS) and Ground Users (GUs). We study the energy-efficiency gap between the link “BS-UAV-GUs” and the link “BS-GUs”, and jointly optimize UAV relay transmission power and flight radius to achieve the highest energy-efficiency. Firstly, the UAV/BS-GUs channels models and the UAV energy consumption model are built. Secondly, the optimization objective function is formulated to maximize the energy-efficiency gap. Then, the solution of the optimization problem is divided into a two-step iteration process, in which the UAV relay transmission power and flight radius are adjusted to maximize the energy-efficiency gap. Finally, the experimental results under different simulation scenarios (such as cities, forests, deserts, oceans, etc.) are shown to illustrate the effectiveness of the proposed algorithm. The results show that the proposed algorithm can always find the optimal UAV relay transmission power and flight radius settings, and achieve the largest energy-efficiency gap. The convergency speed of the proposed algorithm is fast, and can obtain the optimal solution within only a few iterations. 相似文献
155.
复合材料混合模式分层断裂的实验表征 总被引:1,自引:0,他引:1
介绍了一种碳纤维增强复合材料混合模式层间断裂试验方法,它采用改进的混合模式弯曲试验构型,可对Ⅰ型对Ⅱ型断裂按比例加载,且使用对开裂的梁形试件。 相似文献
156.
157.
IEEE802.16e技术以其高带宽、强移动性正成为宽带无线接入技术的焦点,与此同时,移动用户站在移动中如何去节省能量、延长工作时间,也日益被人们所关注。文章研究了IEEE802.16e无线城域网中的节能机制问题。首先介绍了IEEE802.16e下移动用户站的睡眠模式,然后对该睡眠模式建立分析模型,并根据模型进行了仿真,最后对仿真结果进行了总结。 相似文献
158.
Numerical study of the generation of linear energy transfer spectra for space radiation applications
Francis F. Badavi John W. Wilson Abigail Hunter 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
In analyzing charged particle spectra in space due to galactic cosmic rays (GCR) and solar particle events (SPE), the conversion of particle energy spectra into linear energy transfer (LET) distributions is a convenient guide in assessing biologically significant components of these spectra. The mapping of LET to energy is triple valued and can be defined only on open energy subintervals where the derivative of LET with respect to energy is not zero. Presented here is a well-defined numerical procedure which allows for the generation of LET spectra on the open energy subintervals where, in spite of their singular nature, the spectra are integrable. The efficiency of the numerical procedures is demonstrated by providing examples of computed differential and integral LET spectra and their equilibrium components for historically large SPEs and 1977 solar minimum GCR environments. Due to the biological significance of tissue, all simulations are done with tissue as the target material. 相似文献
159.
液体火箭发动机试验流量测量技术研究 总被引:1,自引:0,他引:1
介绍了液体火箭发动机试验推进剂流量测量技术与方法,阐述流量测量系统设计要点、传感器的选择与安装工艺、现场校准技术、信号调理器设计、抗干扰措施、数据分析与提供方法。文中论述的测量技术实现了发动机试验流量参数的准确测量,为发动机性能评价提供准确、可靠的依据。 相似文献
160.
李楠江卓远 《民用飞机设计与研究》2013,(2):13-17
在对国外飞机环境控制与热能综合管理技术进行分析的基础上,以某飞机为背景,开展环境控制系统与热能综合管理系统的初步研究。提出某飞机环境控制与热能综合管理系统方案,初步完成各子系统能量的合理匹配,以期为民用飞机综合热能管理技术的预研发展提供依据。 相似文献