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本文利用欧洲的EISCAT雷达观测资料及与这配合的地磁观测数据,用电离层参数直接计算和地面磁场反演两种方法导出了极区电离层Hall电导率,特别显示出在强对流电场激发的E层等离子体不稳定波对电子加热情况下,电导率明显增高。 相似文献
23.
为了准确模拟飞行器在高速飞行时的瞬态气动加热状态,必须使用快速、高精度的计算机瞬态热能控制系统,对气动模拟试验的加热过程,实行快速、高精度的非线性动态控制.为此,传感器的快速、高精度"E-T"转换是一个必须解决的非常重要的问题.提出一种高速飞行器瞬态气动加热控制系统中传感器的快速、高精度"E-T"转换方法.该方法具有计算简单、转换速度快、校正精度高的优点,使用该方法实现了高速飞行器气动加热过程中温度场高速变化状态下的瞬态非线性动态控制. 相似文献
24.
高空高速无人飞行器热控制系统设计 总被引:1,自引:0,他引:1
针对飞行时间短、速度和高度变化快、表面温度波动大的无人飞行器UAV(Unmanned Aerial Vehicles)热控制系统设计难题,提出了一种可解决实际工程问题的热分析计算方法.即把热天工况、冷天工况和标准天工况作为设计/试验工况;采用参考温度法、高超音速工程预测法或计算流体动力学CFD(Computational Fluid Dynamics)数值模拟法,确定了飞行器表面温度分布,并把其作为后续热分析数学模型的外边界条件;分析结构热容量对瞬态热载荷的影响,建立与之相应的边值问题方程,并采用有限差分法求解;根据高空高速飞行特点及瞬态热载荷值,确定仪器设备舱调温系统方案. 相似文献
25.
V.E. Kunitsyn A.M. Padokhin A.E. Vasiliev G.A. Kurbatov V.L. Frolov G.P. Komrakov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
The purpose of this work is to report the experimental evidences for the influence of perturbations in the electron density in the dayside mid-latitude ionosphere, that are caused by high-frequency heating of the F2 layer, on the GNSS signals. The experiments were carried out at the Sura heater (Radio Physical Research Institute, N. Novgorod). During the sessions of ionospheric heating with different time modulations of the radiated power the rays linking the navigational satellites with the ground receiver intersected the heated region. Variations in the total electron content (TEC) were studied; these variations are proportional to the reduced phases of navigational signals. It is shown that with the square-wave modulation of the radiated power (with periods of 1, 6, 10 and 15 min), perturbations with periods of the main modulation of heating and its harmonics appear in the spectrum of TEC variations. Examples are presented of identification of the heating-induced variations in TEC, including determination of the amplitudes and time characteristics of these variations. 相似文献
26.
根据波音AMM手册要求,在更换波音737NG飞机上的大气数据系统传感器后,需通过试车测试其自动加温功能。本文研究了波音737NG飞机大气数据系统探头自动加温的工作原理,并提出避免试车的解决方案。 相似文献
27.
R.V. Semenyshyn A.N. VeklichI.L. Babich V.F. Boretskij 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
Plasma of the free burning electric arc between Ag–SnO2–ZnO composite electrodes as well as brass electrodes were investigated. The plasma temperature distributions were obtained by Boltzmann plot method involving Cu I, Ag I or Zn I spectral line emissions. The electron density distributions were obtained from the width and from absolute intensity of spectral lines. The laser absorption spectroscopy was used for measurement of copper atom concentration in plasma. Plasma equilibrium composition was calculated using two independent groups of experimental values (temperature and copper atom concentration, temperature and electron density). It was found that plasma of the free burning electric arc between brass electrodes is in local thermodynamical equilibrium. The experimental verification of the spectroscopic data of Zn I spectral lines was carried out. 相似文献
28.
Marking arbitrary three-dimensional(3D) target curves on given objects with curved surface is required in many industrial fields, such as fabric prepreg placement in composite material part fabrication, product assembly, surface painting for decoration, etc. A shortcut to the solution of this intractable problem is proposed by utilizing a galvanometric laser scanner(GLS) with the aid of a camera. Without using the existing tedious GLS calibration procedures,the proposed method directly establishes a mapping between the 3D coordinates of the laser spots on the object surface and the control voltages of the scanner. A single-hidden layer feedforward neural network(SLFN) is employed to model the mapping. By projecting a dense grid of laser spots on the object to be marked and simultaneously taking only one image, the SLFN model is trained in minutes via a linear solving mechanism. Experiments demonstrate that the trained SLFN model has a good generalization performance for marking 3D target curves. The 3D laser marking errors on experimental objects are less than 0.5 mm. The proposed method is especially suitable for on-site use and can be conveniently extended to multiple GLSs for marking large complex objects. 相似文献
29.
介绍了激光器的主要性能指标,根据实际需要进行了激光性能测试设备的研究,提出了一种周全的激光性能测试设备研制方案,对该设备的结构设计、光路设计、以及测试方法作了详尽论述。设备中利用两对相互垂直的P分光镜和S分光镜以补偿偏振光在45°面上透反射率不同而造成的测量误差,进一步保证了激光能量测试的准确性。误差分析结果表明该设备满足实际应用中对激光器性能的测试要求。 相似文献
30.