The impact of US export controls on the Canadian space industry

The International Traffic in Arms Regulations (ITAR) govern the export of defense-related technologies and services from the USA. In 1999 Canada's exemption to ITAR was suspended because of American objections over some Canadian companies retransferring US technology to third countries. This paper is a first attempt to quantify the impact of ITAR on the Canadian space industry. Thirty-two space-related companies were contacted and a total of nine responses were received, representative of around 60% of the Canadian space industry in terms of workforce and revenue. According to the results, the Canadian space industry has been relatively effective in meeting the challenges imposed by ITAR. However, these workarounds do not diminish its negative impacts, particularly with respect to cost and schedule. It is expected that ITAR will continue to affect the Canadian space industry, as no near-term relief from the current regulatory environment is on the horizon.     

Complexity,Forced and/or Self-Organized Criticality,and Topological Phase Transitions in Space Plasmas

The first definitive observation that provided convincing evidence indicating certain turbulent space plasma processes are in states of ‘complexity’ was the discovery of the apparent power-law probability distribution of solar flare intensities. Recent statistical studies of complexity in space plasmas came from the AE index, UVI auroral imagery, and in-situ measurements related to the dynamics of the plasma sheet in the Earth's magnetotail and the auroral zone. In this review, we describe a theory of dynamical ‘complexity’ for space plasma systems far from equilibrium. We demonstrate that the sporadic and localized interactions of magnetic coherent structures are the origin of ‘complexity’ in space plasmas. Such interactions generate the anomalous diffusion, transport, acceleration, and evolution of the macroscopic states of the overall dynamical systems. Several illustrative examples are considered. These include: the dynamical multi- and cross-scale interactions of the macro-and kinetic coherent structures in a sheared magnetic field geometry, the preferential acceleration of the bursty bulk flows in the plasma sheet, and the onset of ‘fluctuation induced nonlinear instabilities’ that can lead to magnetic reconfigurations. The technique of dynamical renormalization group is introduced and applied to the study of two-dimensional intermittent MHD fluctuations and an analogous modified forest-fire model exhibiting forced and/or self-organized criticality [FSOC] and other types of topological phase transitions. This revised version was published online in August 2006 with corrections to the Cover Date.     

TVC/PSM飞机的过失速动态边界及敏捷性分析

以飞机为质点，考虑在最少输入数据情况下，曲于转弯速率图并从能量的角度计算和分析了TVC/PSM飞机的过失速动态边界，选取敏捷性尺度空战周期时间和指向裕度，对比分析了TVC/PSM飞机和传统飞机的敏捷性，得出了一些有益的结论，并提出了一些建议。     

Performance of a two-layer LEO satellite communication network

A novel two-layer low Earth orbiting (LEO) satellite network is proposed. Comparing with a single layer global network, not only the system performance is improved but also the number of satellites can be reduced. The main ideas include (1) to raise the altitude of the original global network, and (2) to add several satellites at lower altitude to form a regional network to serve calls from the areas of heavy traffic. In order to fully utilize the benefits of the two-layer network, additional functions such as adjustable beam and dynamic channel management are added. Call blocking rate is derived. Numerical examples are provided to demonstrate several interesting phenomena.     

航空发动机百年回顾

本系统回顾了航空发动机的百年发展，可供航空史研究参考。     

Attitude control of a bias momentum satellite using moment ofinertia

Analysis on the attitude controller based upon moment of inertia distribution for a bias momentum satellite is discussed. Spacecraft moment of inertia distribution is represented in the form of product of inertia terms in the system inertia matrix. The product of inertia between orthogonal body axes of the satellite is used to build a controller which controls the nutational motion caused by the angular momentum of the wheel. The attitude controller in the pitch axis controlling the pitch motion as well as nutational dynamics in the roll/yaw planes is analyzed in detail. Analytic expressions using linearized equations are derived providing further insight into the dynamic coupling effect among orthogonal body axes     

时分式平面—立体电视图像转换器

时分式平面－立体电视图像转换器是由视频图像信号处理电路、控制信号产生电路和液晶眼镜驱动电路三部分构成，根据其构成和工作原理，可采用多种具体电路来实现。     

空气动力迟滞引起飞机横航向极限环振荡的一种近似解法

 本文给出近似解析公式,确定空气动力迟滞引起的飞机横航向极限环振荡特性。计算表明,它与文献[1、2]中提出的数值迭代法求得的结果相当一致,并消除了该文中求出的滚转迟滞引起的滚转速率极限环振荡振幅不是最大幅值的缺陷。     

Real-time stereoscopic applications using the goes operational satellites

We have investigated the use of real and synthetic stereo satellite images and stereo graphics in applications such as cloud-tracked winds, severe storm cloud analysis, and general meteorological interpretation. We have concluded that a stereo meteorological presentation is possible and desirable in an operational environment. Synthetic stereo could be used immediately in cloud-tracked wind operations. The presentation allows one to appreciate the interrelations between cloud motions and cloud structures, especially in multi-layered situations. Reprocessing of FGGE tropical wind sets with a synthetic stereo presentation showed some improved yields of low-level vectors, a significant increase in mid-level vectors, and very little change in the high-level vectors. Severe local storm real-stereo presentations are possible operationally because the 15 minute RISOP operations of GOES-East allow simultaneous scanning of both geosynchronous satellites twice per hour. The real-stereo height measurements of overshooting turrets are an improvement over infrared heights and can be used to monitor the strength of the thunderstorm updraft. Synthetic stereo presentations of thunderstorm tops can be presented in a non-linear fashion which stretches out the cloud top features. The synthetic stereo presentation is easier for most people to see. We recommend the use of a hybrid system where the viewing is done on the synthetic stereo image and the quantitative measurements are done on the real-stereo pairs.