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T.A. Jacobsen J. Tr∅im B.N. Maehlum M. Friedrich 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):123-127
A “mother-daughter” rocket code-named “Electron 2” was launched from And?ya, Northern Norway in November, 1978. The “daughter”, carrying a 10 keV electron accelerator, was separated from the “mother” payload with a speed of 0.4 m/s. A series of plasma diagnostic instruments were included on the “mother” to study effects produced by the interaction between the electron beam and the ionospheric plasma. Results obtained by two different plasma probes are presented. It was found that pronounced changes in the ambient electron population took place in regions penetrated by the electron beam. Estimates of the dimensions of the disturbed region are presented. 相似文献
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Claudia Borries Volker Wilken Knut Stanley Jacobsen Alberto García-Rigo Beata Dziak-Jankowska Guram Kervalishvili Norbert Jakowski Ioanna Tsagouri Manuel Hernández-Pajares Arthur A. Ferreira Mainul M. Hoque 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(2):919-920
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用于铝合金的集成计算材料工程是将微观(10-10~10-8m)、细观(10-8~10-4m)、介观(10-4~10-2m)和宏观(10-2~10 m)等多尺度计算模拟和关键实验集成到铝合金设计开发的全过程中,通过成分-工艺-结构-性能的集成化,把铝合金的研发由传统经验式提升到以组织演化及其与性能相关性为基础的科学设计上,从而大大加快其研发速度,降低研发成本。本文详细阐述了原子尺度模拟、相图计算、相场、元胞自动机和有限元等计算模拟方法及微结构表征和性能测定的实验方法,论述了其在铝合金研发中所发挥的具体作用。基于集成计算材料工程,提出了从用户需要、设计制备和工业生产3个层面研发铝合金的具体框架。通过2个应用实例,展示了集成计算材料工程在铝合金研发中的强大功能,这也为新型铝合金及其它新材料的设计和开发提供了新模式。 相似文献
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为了研究水润滑高分子材料轴承的微观界面的流场特性,本文以单个微凹体中的流场作为研究对象,建立了单个微凹体流动模型。采用多松弛格子玻尔兹曼方法MRT-LBM (multi-relaxation time lattice Boltzmann method)对单个微凹体的流体流动问题进行数值模拟。研究了流场中速度的变化规律,以及流场中流线分布随雷诺数的变化规律。结果表明当雷诺数较低时,流场处于稳定性流动状态;当雷诺数达到一定程度时,流场处于周期流动状态;当雷诺数很高时,流场处于湍流运动状态。探究微观流场中复杂的变化规律,为研究水润滑高分子材料轴承的润滑和摩擦性能提供一些理论支撑。 相似文献
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针对车载捷联惯导系统(SINS),提出一种快速行进间粗对准方法。将捷联矩阵分解为3个矩阵相乘,利用GPS提供的载体在导航坐标系的速度和里程计提供的载体在载体坐标系的速度构建不共线向量,求解初始载体坐标系相对惯性坐标系的常值转换矩阵,进而求得初始姿态矩阵。该对准方法对载车的唯一要求是在对准过程中做一个转弯机动。与现有对准方法相比,该方法没有用到加速度计信息。仿真结果表明,该方法能在1 min之内完成粗对准,采用零偏为0.1(°)/h的低精度陀螺,对准误差小于0.3°。 相似文献
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J.A. Holtet B.K. Pran A. Egeland B. Grandal T.A. Jacobsen B.N. Maehlum J. Trøim 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):117-122
The sounding rocket POLAR 5 carried a 10 keV electron accelerator and various diagnostic instruments in a mother-daughter configuration. Onboard wave receivers recorded several types of VLF wave phenomena directly associated with the operation of the accelerator, with delays from 5 to 50 ms after the injection of the electrons. These delayed after-effects range from broadband noise, f > 3 kHz, observed above 170 km, through narrow band emissions at 2 and 5.6 kHz which appeared when the rocket crossed a region with precipitation of energetic electrons, to emissions covering frequencies from 3–4 to well above 100 kHz observed within the E-region (150-95 km). The latter was also associated with apparent changes in electron density. The observed emission properties indicate that the region perturbed by the beam and the neutralizing return current to the daughter may be a favoured generation region. 相似文献
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