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自从本世纪30年代末,美国西科斯基飞机公司制造了世界上首架具有使用价值的VS—300型直升机以来,经过半个多世纪界内人士的不懈努力,世界军民用直升机技术与其前代相比已经有了脱胎换骨的发展。直升机在各种军民用领域的应用,在今天的欧美一些发达国家,如美、加、英、法、俄等国已经达到了成熟化、普遍化的水平,而且在推动社会发展,促进国防和国民经济建设中发挥了重要作用。竞争不断,创新不止──世界民用直升机发展走向@赵秀丽 相似文献
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日本的两种无人直升机 总被引:1,自引:0,他引:1
雅马哈公司研制的RMAX民用无人直升机和富士重工研制的军用无人直升机前视观察系统(FFOS),是日本近年来研制的非常成功的两种无人直升机,并已在日本军民用领域广泛应用 相似文献
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目前,人们正在寻求将夜视增强技术应用于直升机民用领域的途径。近几年,军用与公用直升机才开始结合夜视目镜使用,不久,它将在有限的应用中为民用用户带来了好处。美国联邦航空局(FAA)对民用领域使用夜视目镜的态度遭到了一家主要的“紧急医疗救护(EMS)”机构的反对,并诉诸于法律。FAA原有的观点是:在民用直升机的运营中使用夜视目镜可能是“不安全的”,并可能导致“草率和鲁莽的使用一架直升机”。一位联邦 相似文献
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进入21世纪,数字化、信息化、先进材料、飞控和航空电子技术的迅速发展,为传统直升机技术性能进步起着重要推动作用,使直升机在日益激烈的市场竞争环境中,面对空管部门越来越苛刻的飞行标准,能够直面未来挑战,充分利用其独特的性能特点,继续发挥在军民用领域无以替代的重要作用 相似文献
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2006~2015年10年间,全球直升机市场在产量上呈现民用直升机缓慢下降,军用直升机快速增长的非均衡发展态势;在产值上则是军民用直升机均呈上升趋势,而且军用直升机产值几乎增长了一倍,这主要源于市场对于高性能、先进技术产品需求度增加以及其他人工成本增加等因素。美欧几家主要的直升机制造商仍将在这10年间占据着全球直升机市场的垄断地位。 相似文献
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简要分析了适航条例对民用直升机材料的有关规定,结合民用直升机的设计思想,从标准化的视角阐述了民用直升机材料工作的具体内容,探讨了民用直升机材料适航符合性分析与验证工作的重点及难点,指出了目前民用直升机材料标准化工作中存在的问题,并对如何开展民用直升机的材料标准化工作提出若干设想。 相似文献
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H_∞滤波算法及其在GPS/SINS组合导航系统中的应用 总被引:4,自引:0,他引:4
在对 H∞ 估计问题进行数学描述的基础上,建立了一种 H∞ 次优滤波算法的迭代方程。定性讨论了H∞滤波算法与传统 Kalman滤波器的关系,通过在 GPS/SINS组合系统中的实际应用进一步从精度、鲁棒性等性能指标方面对 H∞ 滤波和 Kalman滤波算法进行了比较。仿真结果表明,在理想条件下,Kalman滤波方法具有较高的精度;但是,当系统模型和外部干扰统计特性发生变化时,H∞ 滤波算法明显具有良好的鲁棒性能,同时,估计精度也较高,有效地克服了 Kalman滤波器存在的局限性。 相似文献
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将结构参数不确定性问题引入到参数化的一般 H∞ 控制器中 ,并考虑 H2 性能指标 ,提出了 1种被控系统中存在结构参数不确定性的混合 H∞ /H2 控制器的设计方法 ,给出了相应问题求解的充分必要条件 ,问题的解归结为求解 3个 Riccati方程。设计的控制器在某型双转子涡喷发动机气动热力学非线性模型上进行了仿真验证 相似文献
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对于航空发动机结构参数不确定性系统,引用文献[1]的代数Riccati不等式负定裕度的概念,给出了按基准模型设计H∞状态反馈控制器时确定鲁棒稳定界的方法及其扫描搜索算法. 相似文献
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Due to the outstanding brightness of Comet Hale-Bopp measurements of water production rates were possible over a wide range
of heliocentric distances (up to 5 AU). A variety of observing techniques have been used, including radio observations, IR-
and UV-measurements. The H2O-production of a comet is closely connected with the energy balance and the composition of its surface. By comparing measured
and calculated rates it is possible to derive properties of the nucleus. The results of this study demonstrate the importance
of seasonal effects and show that a low thermal conductivity enhances the water production rate. The observations can be matched
with a relatively low, lunar-like thermal conductivity. A lower size limit for the nucleus of Hale-Bopp is derived.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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Hiroki Kurokawa 《Space Science Reviews》1989,51(1-2):49-84
This paper gives a review of the recent high-resolution H observations of solar flares and flare-productive active regions. From studies of the morphological and evolutional features of H flare emitting regions, two types of two-ribbon flares, which are termed separating two-ribbon flare and confined two-ribbon flare, are discussed. The former is characterized by conspicuous separating motions or expanding motions of the H two ribbons, whereas the latter shows only a short range of or no separating motions of the two ribbons. The explosive compact flares, which occur in some compact newly-emerging flux regions, are also discussed.Attention is paid to the successive and impulsive brightenings of H flare points which form the H flare kernels and the front lines of H two ribbons at the impulsive phases of flares. Temporal relationships between H line intensities or profiles and hard X-ray or microwave emissions are discussed to discriminate the energy transport mechanisms in the flare loops.H monochromatic image of high spatial resolution, at the present time, is the most sensitive detector for finding the first appearance of newly-emerging magnetic flux region and the developing features of sheared configuration of magnetic field, both of which are the key factors in flare energy build-up processes. It is suggested that the successive emergence of a twisted magnetic flux rope might be essential for the production of a major flare.Contributions from the Kwasan and Hida Observatories, Kyoto University, No. 292. 相似文献
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面临全球经济危机的严峻挑战,国内外一些航空公司纷纷消减航线、缩减航班数量,以期降低运营成本,减少亏损。而世界最大的航空公司——达美航空公司1月12日在上海宣布,上海与底特律之间的直飞航班将于今年6月如期开通。为此,记者专访了达美航空公司首席执行官理查德·安德森(Richard H. Anderson)。他表示,达美航空公司全球高层领导此次访华重申了达美航空对中国市场 相似文献
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The statistical distribution of all available published D/H ratios of carbonaceous chondrites is presented. The possible interpretations
of this distribution are reviewed at the global scale of the solar system planetary objects and at the scale defined by the
carbonaceous meteorites. New issues concerning the chemical origin of the deuterium enrichment in solar system water and organic
molecules are put into light by this exercise. This distribution is a robust constraint on the origin of water on Earth.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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J. L. Linsky 《Space Science Reviews》2007,130(1-4):367-375
Analysis of UV spectra obtained with the HST, FUSE and other satellites provides a new understanding of the deuterium abundance
in the local region of the galactic disk. The wide range of gas-phase D/H measurements obtained outside of the Local Bubble
can now be explained as due to different amounts of deuterium depletion on carbonaceous grains. The total D/H ratio including
deuterium in the gas and dust phases is at least 23 parts per million of hydrogen, which is providing a challenge to models
of galactic chemical evolution. Analysis of HST and ground-based spectra of many lines of sight to stars within the Local
Bubble have identified interstellar velocity components that are consistent with more than 15 velocity vectors. We have identified
the structures of 15 nearby warm interstellar clouds on the basis of these velocity vectors and common temperatures and depletions.
We estimate the distances and masses of these clouds and compare their locations with cold interstellar clouds. 相似文献