Innovative design and optimization of a two-dimensional deployable nine-grid planar antenna mechanism with a flat reflection surface

With the development of the aerospace industry, space missions are becoming more complicated and diversified, and there is a demand for antenna mechanisms with a larger physical aperture. In this paper, a planar deployable mechanism is proposed, which can form a flat reflection surface with a small gap between plates. To this end, a novel large-scale two-dimensional deployable nine-grid planar antenna mechanism is designed. First, two antenna folding schemes and four supporting mechanism schemes...     

Interfacial characteristics in CNTs-AgCuTi systems

AgCuTi-based composite fillers reinforced with Carbon Nanotubes（CNTs） were prepared by mechanical ball milling and ultrasonic agitation. The morphological features, chemical components, and melting characteristics of the composite fillers with different content of CNTs addition were investigated using Field Emission Scanning Electron Microscopy（FESEM）, XRay Diffraction（XRD） and a Differential Scanning Calorimeter（DSC）. After being heated at 900 ℃, the microstructure of the composite fillers was ...     

Improvement in Time Efficiency in Numerical Simulationfor Solid Propellant Rocket Motors （SPRM）

The main purpose of the present work is to study the possibilities of reducing calculation time while maintaining the validity in the numerical simulation of the combustion product flow in SPRM chamber. Three ways of decreasing the calculation time-the use of numerical methods of high accuracy order, the reduction in spatial dimension of the problem, and the use of physical features of the processes in SPRM chamber while constructing a calculation model-were considered. Presented calculation data show that the use of these approaches makes it possible to reduce the time for solving the problems of SPRM simulation significantly (up to 100 times). Also conclusions about the applicability of the mentioned above approaches in SPRM design were made.     

Electrochemical drilling of small holes by regulating in real-time the electrolyte flowrate in multiple channels

Electrochemical drilling(ECD) provides an alternative technique for drilling multiple small holes in difficult-to-machine materials in numerous industrial applications such as for aeroengines. The value and fluctuation of electrolyte flowrate can seriously affect the machining stability and hole quality in ECD. In particular, when drilling multiple holes, the distribution and fluctuations of the electrolyte flowrate in each channel could influence the uniformity of the electrolyte flowrate among...     

Unimpeded Routes in the Blue Sky

The air transport in China is developing rapidly with an annual average growth rate of20 %since the reform and open to the outside.The rising air traffic will make ATC more difficult.With questions about China‘s ATC development at present and in the future,the reporters of IA interviewed to Mr.Chen Xuhua,the director general of the Air Traffic Managment Bureau of the CAAC.     

Improvements of Edges Diffraction Computing in GRECO

图形电磁计算(GRECO)方法是计算复杂目标高频区雷达散射截面(RCS)的有效方法之一。分析了原始GRECO方法在判定目标图象棱边象素的不足之处，给出了相应的改进措施。改进后的软件能够更准确、充分地判定目标的棱边象素及获得棱边参数。在边缘绕射场的计算方面，指出了相关文献中存在的错误，给出了基于等效电磁流法(MEC)和物理绕射理论(PTD)的边缘绕射场计算式，及与物理光学(PO)场叠加求取RCS的完整表达式。计算实例表明，新的方法具有更高的准确度，与实验测量值吻合。     

First Summit On China Airports in Shanghai

he first summit on China airports was held inShanghai from April 4 to 6. The meeting wassponsored by Airports Council International (ACI),China Civil Aviation and JF Pearson.ACI Director General Robert Aaronson, ZhangGuanghui, Director General of Airport Department ofCAAC, Wu Nianzu, Chairman and President ofShanghai Airport Authority, attended the summit anddelivered speeches.The summit discussed and analyzed the new policiesof China's civil aviation industry and howChinese ai…     

OUR READERS SAY IT ALL in 2003

中航第一集团公司总经理:刘高倬 2003年是人类从事航空飞行100周年,中国的航空工业也走过了半个世纪的里程。在此,我谨通过《国际航空》杂志,向国内外航空工业界的新老朋友们致以良好的祝愿,向所有关心支持中航第一集团发展的各界人士表示衷心的感谢！我希望《国际航空》杂志继续为国际间航空领域交流与合作,为中国航空工业的发展起刭积极作用,为实现集团公司快速成长、创造卓越、跻身世界航空工业强者之林做出应有的贡献。     

Aeronautics — a pioneer in European integration

As the first trans-national European industry, aeronautics has been a pioneer in European integration. The European aeronautics business is now a leading player on the world stage contributing to Europe's standing in the global market. Aeronautics creates employment and advances the cutting-edge technology sector in Europe — in education, business and defence matters. Taking its responsibility for the environment seriously, Europe sets the pace for environmental standards in international aeronautics. After all, air travel has become more convenient, practical and affordable — to the benefit of all citizens.     

Experimental Investigation of Hydrocarbon-fuel Ignition in Scramjet Combustor

模拟飞行Ma=3．5的超燃冲压发动机的燃烧室进口条件，采用氢为先锋火焰，在氢氧燃烧加热脉冲风洞上，对超燃燃烧室煤油燃料的点火和火焰稳定进行了实验研究，实现了煤油的点火和火焰稳定。实验测量了燃烧室壁面压力分布，并拍摄了燃烧火焰紫外光图像。实验表明，在燃烧室进口温度较低(小于900K)的条件下，在超燃燃烧室中实现煤油自燃十分困难，采用氢为先锋火焰实现煤油的点火是较为有效的途径之一。     

Do drones have a realistic place in a pandemic fight for delivering medical supplies in healthcare systems problems?

The advancement of Unmanned Aerial Vehicle (UAV) technology in terms of industrial processes and communication and networking technologies has led to an increase in their use in civil, business, and social applications. Global rules in most countries had previously limited the use of drones to military applications due to their deployment in the open air, drones are likely to be lost, destroyed, or physically hijacked. However, more recently, the presence of COVID-19 has forced the world to present new implementing measures which will also widen the use of drones in civil and commercial and social applications, especially now in the delivery of medicines for medical home care. In the period of required public isolation as a consequence of the SARS-COV-2 pandemic, this knowledge has become one of the principal partners in the fight against the coronavirus. This paper offers a summary of the medical drone manufacturing, with a specific emphasis on its approval by the pharmaceutical sector to solve logistical problems in healthcare during times of sensitive need. We also discuss the numerous challenges to be met in the integration of drones to save our lives and suggest future research directions. The question that arises for this problem, how to optimize delivery medical supplies times in-home health care made up of drones? We conducted a synthesis literature review devoted to the use of UAVs in healthcare with their different aspects. A total of different research made are given to describe the role of UAV in Home healthcare with the presence of SARS-COV-2. We conclude that the drones will be able to optimize the way of eliminating contamination with a very high percentage (through the reduction of human contact) with the increase of the flexibility of the flight (reaching the less accessible regions every hour of the day).     

Hand in Hand of Airlines and the Bank

OnAngust13,ChinaEasternAirGroupandChinaEasternAirlinsCo.,Ltd.signedanagreementoftheentirecooperationwithIndustrial&CommerialBankofChina,whichstipulatedthatthebankwouldofferChillEastemaeredhatofRMB30billionyuanandtheall-aroundfinancialservicetill2000.Accodringtotheagreement,ChinaEastheAirlinesCo.,Ltd.,thecoreofthegroup,willreceiveanaircraft-leasingguaranteecreditlindtof$2.5billionandcreditlndofloansinforeignexchangeofRMB9billionyuan,besides,theothersubsidiariesofthegroupwillbeoffereda…     

Credit Determination of Fibre Channel in Avionics Environment

Fibre channel (FC) is the main candidate architecture for “unified network”. Flow control deals with the problem in which a de- vice receives frames faster than it can process them. Credit is an important service parameter for fibre channel flow control. Configuring the credit reasonably can avoid buffer overflow in nodes. This paper derives the mathematic relationships among credit, bandwidth and message sets under real-time condition according as three main topologies of fibre channel, and proposes the credit determination and the optimal credit for typical message sets. This study is based on the features of hard real-time communications in avionics environ- ment.     

Development and Application of Laser Peening in Japan

Recent advances in laser technology have yielded amultitude of innovative processes and applications invarious industries. Laser peening without protectivecoating (LPPC) is a typical example and blazes a trail inthe field of preventive maintenance of operating nuclearfacilities, taking full advantage of inertia-less processover mechanical treatment[1]. LPPC introduces a compres-sive residual stress on metal surface by simply irradiat-ing laser pulses under water environment[2] . A remotepro…     

March in the Sky with 40 Year''''s Confidence

ＭａｒｃｈｉｎｔｈｅＳｋｙｗｉｔｈ４０Ｙｅａｒ＇ｓＣｏｎｆｉｄｅｎｃｅ（ＳｈｅｙａｎｇＬｉｍｉｎｇＥｎｇｉｎｅＭａｎｕｆａｃｔｕｒｉｎｇＣｏ）ＧｅｎｅｒａｌＭａｎａｇｅｒ；ＳｕｎＭｉｎｇｔａｎｇＦｏｕｎｄｅｄｏｎ３１，Ｍａｒｃｈ，１９５４，Ｌｉｍｉｎ...     

Periodic or random acceleration in solar flares?

The issue whether acceleration and injection of electron beams is coherently modulated by a single quasi-periodic source, or whether the injection is driven by a stochastic process in time or (eventually fragmented) in space, is investigated by menas of a periodicity analysis of metric type III bursts.We analyze 260 continuous type III groups observed byIkarus (ETH Zurich) in the frequency range of 100–500 MHz during 359 solar flares with simultaneous 25 keV hard X-ray emission, in the years 1980–1983. Pulse periods have been measured between 0.5 and 10 s, and can be described by an exponential distribution, i.e.N(P) e ^–P/1.0s. We measure the mean periodP and its standard deviation p in each type III group, and quantify the degree of periodicity by the dimensionless parameter p/P. The representative sample of 260 type III burst groups shows a mean periodicity of p/P=0.37±0.12, while Monte-Carlo simulations of an equivalent set of truly random time series show a distinctly different value of p/P=0.93±0.26. This result suggests that the injection of electron beams is periodically modulated by a particle acceleration source which is either compact or has a global organization on a time scale of seconds.     

Application of Road Information in Ground Moving Target Tracking

A new algorithm is developed to achieve accurate state estimation in ground moving target tracking by means of using road information. It is an adaptive variable structure interacting multiple model estimator with dynamic models modification （DMM VS-IMM for short）. Firstly, road information is employed to modify the target dynamic models used by filter, including modification of state transition matrix and process noise. Secondly, road information is applied to update the model set of a VS-IMM estimator. Predicted state estimation and road information are used to locate the target in the road network on which the model set is updated and finally IMM filtering is implemented. As compared with traditional methods, the accuracy of state estimation is improved for target moving not only on a single road, but also through an intersection. Monte Carlo simulation demonstrates the efficiency and robustness of the proposed algorithm with moderate computational loads.     

Small Scale Alfvénic Structure in the Aurora

This paper presents a comprehensive review of dispersive Alfvén waves in space and laboratory plasmas. We start with linear properties of Alfvén waves and show how the inclusion of ion gyroradius, parallel electron inertia, and finite frequency effects modify the Alfvén wave properties. Detailed discussions of inertial and kinetic Alfvén waves and their polarizations as well as their relations to drift Alfvén waves are presented. Up to date observations of waves and field parameters deduced from the measurements by Freja, Fast, and other spacecraft are summarized. We also present laboratory measurements of dispersive Alfvén waves, that are of most interest to auroral physics. Electron acceleration by Alfvén waves and possible connections of dispersive Alfvén waves with ionospheric-magnetospheric resonator and global field-line resonances are also reviewed. Theoretical efforts are directed on studies of Alfvén resonance cones, generation of dispersive Alfvén waves, as well their nonlinear interactions with the background plasma and self-interaction. Such topics as the dispersive Alfvén wave ponderomotive force, density cavitation, wave modulation/filamentation, and Alfvén wave self-focusing are reviewed. The nonlinear dispersive Alfvén wave studies also include the formation of vortices and their dynamics as well as chaos in Alfvén wave turbulence. Finally, we present a rigorous evaluation of theoretical and experimental investigations and point out applications and future perspectives of auroral Alfvén wave physics.     

China''''s Civil Aviation Industry Announcing Jts Targets in 1999

In1999,thetotaltrafficofChineseairlinesisexpectedtoincrease6.4%overlastyeartoreach9.8billionton-kilometres.Passengertransportwillachieve60million,andpassengertrafficvolumewillreach83.6billionpassengerkilometres,up5%and6.4%respectivelyAtotalof1.5milliontonsofcargo&postand3.5billionton-kilometresofcargo&posttrafficvolumeareestimatedtobeaccomplished,up7.9%and6.5%respectively.ThegeneralaviationOperationwillcomplete4l(XX)Ilighthours.ThemajorbusinessrevenueoftheenterPrisesdirectunderCAACisschedu…