Design and applications of airborne radars in the VHF/UHF band

The simultaneous need for ground penetration and high resolution dictates the use of frequencies less than 500 MHz for imaging ground penetrating radar (GPR) designs. It is possible to build such systems with good performance and yet not interfere with ground installations operating in the same bands. The total number of airborne GPR systems needed to saturate the market is small, (possibly less than ten), and so the buildup of noise in this spectral region occupied by these radars will be negligible. This is fortunate, since there is a clear need for such radars in such areas as humanitarian demining and unexploded ordnance (UXO) mapping. Some formal set of guidelines is needed beyond that given in Part 15 of the FCC regulations, which both recognizes the need for airborne UWB radar operations, and still protects licensed users in the band     

The Radar Support System (RSS): a tool for siting radars andpredicting their performance

The Radar Support System (RSS) is a software tool for assisting the radar siting engineer in determining the best location for a sensor, evaluating performance in a site-specific environment and analyzing operational problems. The RSS uses detailed sensor models, along with digital topographic, land cover and cultural databases, to provide accurate performance predictions. The RSS is currently being used by the FAA to assist in their sensor deployments and analyses     

中国航发北京航空材料研究院

中国航发北京航空材料研究院(中国航发航材院)成立于1956年,是我国“一五”计划156个重点建设项目之一,是我国大型的材料研究工程中心,是全额拨款中央科研事业单位。中国航发航材院是国内面向航空,从事航空先进材料应用基础研究、材料研制与应用技术研究、工程化技术研究、关键件研制交付与小批量生产以及型号应用的综合性科研机构,是我国国防科技工业领域高水平材料研究发展中心,是国家科技创新体系和国防科技创新体系的重要组成部分。     

中国航发北京航空材料研究院

中国航发北京航空材料研究院(中国航发航材院)成立于1956年,是我国“一五”计划156个重点建设项目之一,是我国大型的材料研究工程中心,是全额拨款中央科研事业单位。中国航发航材院是国内面向航空,从事航空先进材料应用基础研究、材料研制与应用技术研究、工程化技术研究、关键件研制交付与小批量生产以及型号应用的综合性科研机构,是我国国防科技工业领域高水平材料研究发展中心,是国家科技创新体系和国防科技创新体系的重要组成部分。     

中国航发北京航空材料研究院

中国航发北京航空材料研究院(中国航发航材院)成立于1956年,是我国"一五"计划156个重点建设项目之一,是我国大型的材料研究工程中心,是全额拨款中央科研事业单位。中国航发航材院是国内面向航空,从事航空先进材料应用基础研究、材料研制与应用技术研究、工程化技术研究、关键件研制交付与小批量生产以及型号应用的综合性科研机构,是我国国防科技工业领域高水平材料研究发展中心,是国家科技创新体系和国防科技创新体系的重要组成部分。     

中国航发北京航空材料研究院

中国航发北京航空材料研究院(中国航发航材院)成立于1956年,是我国“一五”计划156个重点建设项目之一,是我国大型的材料研究工程中心,是全额拨款中央科研事业单位。中国航发航材院是国内面向航空,从事航空先进材料应用基础研究、材料研制与应用技术研究、工程化技术研究、关键件研制交付与小批量生产以及型号应用的综合性科研机构,是我国国防科技工业领域高水平材料研究发展中心,是国家科技创新体系和国防科技创新体系的重要组成部分。     

以推进品牌建设为契机提升材料院质量管理水平

介绍了北京航空材料院以推进品牌建设为契机,提升质量管理水平的一些作法.     

Review of energetic (> 20 ke V) bremsstrahlung X-ray measurements from satellites

Worldwide maps of electron precipitation into the atmosphere can be obtained remotely with a unique separation of spatial and temporal variations by sensing from a satellite the bremsstrahlung X-rays produced in the atmosphere by the incident electrons. From X-ray measurements electron fluxes and energy spectra can be derived over a broad range of energies under both daytime and nighttime conditions. The technique was first demonstrated in 1972 and has now been used sucessfully in several programs. The most continuous and widespread coverage can clearly be achieved from high altitudes, but even at only a few hundred kilometers it has been possible to obtain mappings over a wide area since bremsstrahlung X-ray fluxes are often rather steady in time during the few minute duration of a low altitude satellite pass over the polar region. The satellite bremsstrahlung data already acquired have provided information on the long term morphology of the total fluxes and energy spectra of bremsstrahlung X-rays emitted from a large area and have shown that pronounced longitude structure commonly occurs in the X-ray emissions. The data have tended to be complementary in nature to that obtained by the more well established technique of measuring bremsstrahlung X-rays from balloons, whereby time variations can be studied in detail with more limited geographic coverage. From balloons it is known that the X-rays show a variety of time variations, but many of the faster microburst type phenomena have yet to be observed from satellites. The present status of satellite bremsstrahlung X-ray measurements is reviewed here, some of the key results summarized and suggestions made for future improvements in instrumentation. The review is limited to X-rays > 20 ke V and therefore to the associated precipitation of only the more energetic electrons.     

Gravity Recovery and Interior Laboratory (GRAIL): Mapping the Lunar Interior from Crust to Core

The Gravity Recovery and Interior Laboratory (GRAIL) is a spacecraft-to-spacecraft tracking mission that was developed to map the structure of the lunar interior by producing a detailed map of the gravity field. The resulting model of the interior will be used to address outstanding questions regarding the Moon’s thermal evolution, and will be applicable more generally to the evolution of all terrestrial planets. Each GRAIL orbiter contains a Lunar Gravity Ranging System instrument that conducts dual-one-way ranging measurements to measure precisely the relative motion between them, which in turn are used to develop the lunar gravity field map. Each orbiter also carries an Education/Public Outreach payload, Moon Knowledge Acquired by Middle-School Students (MoonKAM), in which middle school students target images of the Moon for subsequent classroom analysis. Subsequent to a successful launch on September 10, 2011, the twin GRAIL orbiters embarked on independent trajectories on a 3.5-month-long cruise to the Moon via the EL-1 Lagrange point. The spacecraft were inserted into polar orbits on December 31, 2011 and January 1, 2012. After a succession of 19 maneuvers the two orbiters settled into precision formation to begin science operations in March 1, 2012 with an average altitude of 55 km. The Primary Mission, which consisted of three 27.3-day mapping cycles, was successfully completed in June 2012. The extended mission will permit a second three-month mapping phase at an average altitude of 23 km. This paper provides an overview of the mission: science objectives and measurements, spacecraft and instruments, mission development and design, and data flow and data products.     

Proton phase space densities (0.5eV<Ep<5MeV) at midlatitudes from Ulysses SWICS/HI-SCALE measurements

Proton phase space densities in the solar wind frame from suprathermal velocities 10 km s^–1 to 30,000 km s^–1 (0.5 eV–5 MeV) were derived from combined SWICS and HISCALE measurements when Ulysses was at 5 AU and –24° heliolatitude. The period (19–23 January 1993) encompasses a forward/reverse shock pair (20 January, 0500 UT and 22 January, 0300 UT). Strong evidence is found for shock acceleration of pickup protons from interstellar hydrogen at all energies measured.     

Surgery benefits from defense technology: dual use applications ofWright Laboratory Avionics technologies to Computer Assisted MinimallyInvasive Surgery (CAMIS)

Wright Laboratory Avionics Directorate is helping to assemble a team of defense and civilian researchers to transition defense avionics and related technologies to the medical community with the goal of improving the Computer Assisted Minimally invasive Surgery (CAMIS) concept. Key partners include Ohio Aerospace Institute (OAI), a not-for-profit state-chartered agency, Cleveland Clinic Foundation hospital, and Picker International, medical equipment manufacturer. The CAMIS concept is in response to the fact that despite technical advances, most excision surgeries are exploratory rather than remedial. As a result, large incisions are required so the surgeon can first search for the “target” tissue and then, more cutting is needed to remove or destroy the “target”. CAMIS is an opportunity to transition defense avionics technologies to help tackle a critical non-defense issue on the national agenda, health care     

对RLC串联电路中通频带与RLC参数关系的讨论——从一道习题引起的问题

讨论了RLC串联电路中通频带与RLC参数的关系,说明在设计一个RLC串联谐振电路时,在给定谐振频率,电感量和频带宽度时,上下边界频率不能只满足通频带宽度而任意假定,还应满足通频带与RLC这些参数之间关系的表达式.