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161.
针对新型电缆密封结构的密封挡板、密封结构板、橡胶密封板及其连接螺栓建立了有限元模型,考虑了几何、边界及材料非线性因素,计算了模型在螺栓预紧力和气压作用下电缆密封结构的应力和变形,校核该结构的强度是否满足设计要求。结果表明,密封结构的局部出现屈服,需更换更高强度的材料;密封结构密封性能良好,密封性能试验验证了计算结果的合理性。 相似文献
162.
L. Eliasson O. Norberg R. Lundin K. Lundin S. Olsen H. Borg M. André H. Koskinen P. Riihelä M. Boehm B. Whalen 《Space Science Reviews》1994,70(3-4):563-576
The Hot Plasma Experiment, F3H, on boardFreja is designed to measure auroral particle distribution functions with very high temporal and spatial resolution. The experiment consists of three different units; an electron spectrometer that measures angular and energy distributions simultaneously, a positive ion spectrometer that is using the spacecraft spin for three-dimensional measurements, and a data processing unit. The main scientific objective is to study positive ion heating perpendicular to the magnetic field lines in the auroral region. The high resolution measurements of different positive ion species and electrons have already provided important information on this process as well as on other processes at high latitudes. This includes for example high resolution observations of auroral particle precipitation features and source regions of positive ions during magnetic disturbances. TheFreja orbit with an inclination of 63° allows us to make detailed measurements in the nightside auroral oval during all disturbance levels. In the dayside, the cusp region is covered during magnetic disturbances. We will here present the instrument in some detail and some outstanding features in the particle data obtained during the first months of operation at altitudes around 1700 km in the northern hemisphere auroral region. 相似文献
163.
Hannes Alfvén 《Space Science Reviews》1984,39(1-2):65-90
A theory of the origin and evolution of the Solar System (Alfvén and Arrhenius, 1975, 1976) which considered electromagnetic forces and plasma effects is revised in the light of new information supplied by space research. In situ measurements in the magnetospheres and solar wind have changed our views of basic properties of cosmic plasmas. These results can be extrapolated both outwards in space, to interstellar clouds, and backwards in time, to the formation of the solar system. The first extrapolation leads to a revision of some cloud properties which are essential for the early phases in the formation of stars and solar nebulae. The latter extrapolation makes possible to approach the cosmogonic processes by extrapolation of (rather) well-known magnetospheric phenomena.Pioneer-Voyager observations of the Saturnian rings indicate that essential parts of their structure are fossils from cosmogonic times. By using detailed information from these space missions, it seems possible to reconstruct certain events 4–5 billion years ago with an accuracy of a few percent. This will cause a change in our views of the evolution of the solar system. 相似文献
164.
G. K. Parks C. Gurgiolo C. S. Lin K. A. Anderson R. P. Lin F. Martel H. Réme 《Space Science Reviews》1978,22(6):765-776
This article presents some of the new and important particle features that have been detected in the energy range 1 keV to 290 keV by the ISEE-1 and -2 spacecraft near the magnetopause, bow shock, and the interplanetary space. Only examples of data from the first few orbits, when the spacecraft were on the front side, are shown.Paper presented at 13th ESLAB Symposium, Innsbruck, Austria (June 5, 1978). 相似文献
165.
166.
TiAl+Sb合金的研究 总被引:1,自引:0,他引:1
研究了Sb的添加对Ti-32wt-%Al合金的显微组织和力学性能的影响。试验结果表明,Sb的添加量在较大范围内能够使TiAl基合金的室温综合力学性能得到提高。使用光学金相显微镜和SEM对其组织进行了分析,使用X射线衍射仪对典型合金进行了结构和相组成分析。同时,使用SFM对合金试样断口形貌进行了观察分析。 相似文献
167.
Theories and Observations of Ion Energization and Outflow in the High Latitude Magnetosphere 总被引:4,自引:0,他引:4
A review is given of several mechanisms causing outflow at high latitudes of ionospheric ions to the terrestrial magnetosphere. The upward ion motion along the geomaagnetic field can be divided into several categories, including polar wind, bulk ion outflow in the auroral region, upwelling ions and ion conics and beams. More than one ion energization mechanism can be operating within each category, and a combination of categories is important for the total ion outflow. 相似文献
168.
对带弧形尾翼某导弹模型的实验研究表明,具有该种配置的导弹在以平衡攻角为中心俯仰振荡时,动稳定形态随来流马赫数 Ma∞ 变化,呈现非线性特点;亚音速时,稳定在平衡攻角状态;超音速时,存在临界马赫数 Macr,出现极限环运动。对俯仰振荡过程中的实验模型进行了流态显示。 相似文献
169.
170.
不锈钢电解抛光工艺研究 总被引:11,自引:0,他引:11
阐述了不锈钢电解抛光的机理和工艺过程,分析了抛光液各主要成分的作用,同时讨论了工艺参数选择、电场分布分析、辅助电极设计、抛光效果评价等。 相似文献