厉兵秣马迎进博 上海机场服务保障工作准备就绪

10月25日,距第二届中国国际进口博览会开幕倒计时还有10天,上海机场集团认真贯彻落实把进博会越办越好的工作要求,浦东、虹桥两场将以更高水准、更美环境、更佳体验迎接来自世界各地的展客商和观展旅客,让中外嘉宾在上海机场感受上海服务,留下对中国、对上海、对上海机场的美好印象。     

Low-mass evolution from he ignition to beyond the horizontal branch

The evolution of an 0.6 m stellar model during core helium burning is presented. Following the off-center ignition of helium in the core flash, the star remains on the red giant branch for > 10⁶ years, undergoing twelve additional flashes. After leaving the giant branch, the star evolves on the horizontal branch for 8.15×10⁷ years before re turning to the giant branch and undergoing strong helium-shell flashes. The implications for horizontal branch and RR Lyrae stars are discussed.     

ATM/CNS: the response to current and future needs

Sweeping improvements are planned in European ATM to meet the challenge of traffic growth. This paper reviews the possible elements of an improved ATM system and discusses preferred avenues of progress in the light of current research and past experience.     

空间站姿态控制的一种新算法

以四元数作为定位参数对空间站进行姿态控制。首先给出了以四元数表示的系统动力学西式其次提出了非线性三轴姿态控制方法,该方法是以四元数作为反馈量,控制力矩陀螺作为执行元件,利用李亚普诺夫函数对非线性系统进行控制,为大型航天器的姿态控制开辟了新的途径;最后以一空间粘为例进行了姿态控制仿真计算,从而说明以四元数为定位参数的空间站姿态控制方法具有计算速度快、计算精度高等优点。     

推进空域资源优化配置保障航空事业发展需求

一、引言空域是国家的重要战略资源,优化配置合理利用空域资源,对于经济社会发展和国防建设具有重要意义。改革开放以来,在国务院、中央军委领导下,军民航加强空管系统建设,推进空域管理改革,实现了航空事业的快速发展。随着我国民用运输航空飞行量迅速增     

Two-fluid 2.5D MHD Simulations of the Fast Solar Wind in Coronal Holes and the Relation to UVCS Observations

Recent SOHO/UVCS observations indicate that the perpendicular proton and ion temperatures are much larger than electron temperatures. In the present study we simulate numerically the solar wind flow in a coronal hole with the two-fluid approach. We investigate the effects of electron and proton temperatures on the solar wind acceleration by nonlinear waves. In the model the nonlinear waves are generated by Alfvén waves with frequencies in the 10^-3 Hz range, driven at the base of the coronal hole. The resulting electron and proton flow profile exhibits density and velocity fluctuations. The fluctuations may steepen into shocks as they propagate away from the sun. We calculate the effective proton temperature by combining the thermal and wave velocity of the protons, and find qualitative agreement with the proton kinetic temperature increase with height deduced from the UVCS Ly-α observations by Kohl et al. (1998). This revised version was published online in June 2006 with corrections to the Cover Date.     

Application of the restricted problem of three bodies to space mechanics

The most celebrated problem of dynamics, the problem of three bodies, is defined in the first chapter and it is shown how the problème restreint is obtained from the general formulation. This is followed by a historical review of the restricted problem from the point of view of space dynamics applications and the present state of the art is described in some detail. The third and final chapter reviews the major activities in the field of space mechanics and their relation to the restricted problem are pointed out.The purpose of this compte rendu is to demonstrate two theses. Firstly, based on the history of the restricted problem of three bodies, it will be shown that combining recent advances in computer technology and in analytical dynamics with modern topological techniques, a terra firma exists for a new attack on this classical problem.The second thesis is that the restricted problem of three bodies plays a central role in celestial mechanics and in space dynamics. From the second thesis it follows that progress in the solution of this problem will further the case of the entire field of space dynamics.An outline of a combined theoretical and experimental program, leading to possible significant contributions to this pièce de résistance of dynamics, completes the paper.     

Probabilistic estimation of fulfilling favorable conditions to realize the gravity-sensitive processes aboard a space laboratory

We consider a probabilistic estimation of microaccelerations being produced in the inboard environment of an orbital laboratory as a random process; based on this estimation we analyzed a probability of fulfilling the favorable conditions to realize gravity-sensitive processes. The approach suggested can be applied when designing a space laboratory to meet the requirements for the microaccelerations inside the working zone of technological equipment.     

The use of multiple receivers to measure the wave characteristics of very-low-frequency noise in space

Until now most very-low-frequency (VLF) radio noise experiments in the ionosphere, magnetosphere and solar wind have been able to provide only the amplitude and spectral characteristics of VLF phenomena. Experiments using multiple receivers to measure the amplitudes and relative phases of the magnetic and electric wave components, however, can give the wave characteristics in addition. Knowledge of both the spectral and the wave characteristics are desirable in making deductions about the noise source location and mechanism and about the properties of the propagation path. Expressions are derived for obtaining the electromagnetic wave characteristics — wave normal vector, Poynting vector and wave polarization — and the electrostatic wave characteristics — wave normal direction and field magnitude — from the amplitudes and relative phases of the wave components. The antenna systems capable of measuring the necessary wave components on payloads which are not spinning, spinning, or spinning and precessing are described. Consideration is given to the experimental technique of reducing payload interference, of transferring the required data to the ground and of obtaining the desired spatial, frequency, amplitude and phase resolution.The data obtained with such an experiment may represent the superposition of signals from multiple sources and multiple paths and from interference signals. Interpretation of these results is discussed and the use of the results of obtaining information on the source location and mechanism and on the propagation path properties is described. Recently several sounding rocket and satellite experiments capable of measuring some of the wave characteristics have been flown. The results concerning the wave normal directions for several different types of VLF noise phenomena are summarized.