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101.
通过对空客A320系列和波音737NG系列飞机生产制造体系的比较和研究,系统地阐述了从监造计划制定到监造方式选择,再到客户检查项目确定以及现场检查方法等一系列飞机监造工作的基本原则和方法,同时对CAAC签发新引进飞机三证和航空公司工程管理所需的各类文件、表单进行了梳理说明,为航空公司飞机监造工作的开展提供指导和借鉴。 相似文献
102.
Man-Lian Zhang Libo Liu Weixing Wan Baiqi Ning 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
In this paper, we present our recent work on developing an updated global model of the ionospheric F2 peak height hmF2 parameter by combining data from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC/FORMOSAT-3) radio occultation (RO) measurements and from the extended global ionosonde stations. In particular, 10 Chinese ionosonde stations’ data are newly introduced into this study. The modeling technique used is based on a two-layer empirical orthogonal function (EOF) expansion. Global distributions of hmF2 maps calculated using the newly constructed global model and the one provided by the International Reference Ionosphere model (IRI-ITU-R) are compared with the global distributions of hmF2 obtained by the COSMIC RO measurements and quantitative statistical analysis of the differences between the model results and those of the COSMIC RO measurements is made for the low (2008) and high (2012) solar activity years. The obtained average root-mean-square differences (RMSEs) for our model are 27.7 km (11.1%) and 31.0 km (9.8%), respectively for the years 2008 and 2012, whereas those for the IRI-ITU-R model are 39.9 km (16.9%) and 35.0 km (11.6%), respectively. Comparison of the results calculated both by our model and the IRI-ITU-R model with the digisonde observation is also made. The comparisons show that the newly constructed global hmF2 model can reproduce reasonably well the observations and perform better than IRI-ITU-R model. 相似文献
103.
E.I. Astafyeva E.L. Afraimovich A.V. Oinats Yu.V. Yasukevich I.V. Zhivetiev 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
We analyzed the dynamics of global electron content (GEC) for the period 1998–2005 and compared the estimated GEC with variations of the 10.7-cm solar radio emission and with and with GEC values obtained with IRI-2001. We found a strong resemblance between the curves’ shapes for the experimental and modeled GEC: strong semiannual variations are discernible in these series and both curves tend to increase the absolute GEC value during the period of maximum of solar activity. However, there are some significant distinctions, such as absence of 27-day fluctuations in the series of GEC computed by the IRI-2001. On the contrary, observational GEC reflects well dynamics of solar activity: 27-day variations of GEC are very similar to the ones of the index F10.7, but GEC undergoes a lagging of about of 30–60 h as compared to value of the F10.7 index. The relative amplitude of 27-day variations decreases from 8% at the rising and falling solar activity to 2% at the period of its maximum. 相似文献
104.
M.G. Deminov G.F. Deminova G.A. Zherebtsov N.M. Polekh 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
The statistical analysis of the quiet ionosphere F2-layer maximum parameters variability (deviations of NmF2 and hmF2 from the quiet medians, δn and Δh) under solar minimum at day (10–16 LT) and night (22–04 LT) hours based on data of Irkutsk station for 2007–2010 is presented. It is found that the experimental distribution (histogram) of δn can be approximated by a mixture of two normal distributions. The first and second components of the mixture characterize, mainly, relatively weak and strong fluctuations of δn which are presumably associated with the ionospheric effects of the atmospheric gravity waves and of the planetary waves and tides correspondingly. Deviation of the δn histogram from a single normal distribution is most considerable at night hours in winter and equinoxes. For these conditions the weak fluctuations of δn are mainly negative and the strong ones are mainly positive. The Δh histogram is a normal distribution except day hours in winter and equinoxes when a weak deviation of the histogram from the normal distribution occurs. 相似文献
105.
Man-Lian Zhang Chunxu LiuWeixing Wan Libo LiuBaiqi Ning 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
Global modeling of M(3000)F2 and hmF2 based on three alternative EOF (empirical orthogonal function) expansion methods is described briefly. Data used for the model construction is the monthly median hourly values of M(3000)F2 from the ionosonde/digisonde stations distributed around the world for the period of 1975–1985 and the hmF2 data of the same period converted from the measured M(3000)F2 based on the strong anti-correlation existing between them. Independent data of a low (1965) and a high (1970) solar activity year are used to validate the three alternative models based on different EOF expansion methods. Comparisons between the modeled results and observed data for both the low (1965) and high (1970) solar activity years showed good agreement for both M(3000)F2 and hmF2 parameters. Statistical analysis on the differences between model values and observed data showed that all the three alternative models (Model A, B and C) based on the different EOF expansion methods have better agreement with the observed data than the models currently used in IRI. All three alternative EOF based models have almost the same accuracy. Discussion on the preference of the three alternative EOF based models is given. 相似文献
106.
V. Ivanova V. Kurkin V. Ivanov G. Vertogradov V. Uryadov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
An estimation of the F2 ionospheric region critical frequency (foF2) variations using analysis of round-the-world radio sounding data has been made. Experimental data obtained by the Russian chirp-sounders network have been used. For the first time, using experimental data and numerical simulation, the quantitative dependency between the minimum foF2 magnitudes over round-the-world propagation paths and round-the-world maximum usable frequencies has been obtained. 相似文献
107.
S.G. Wang J.K. Shi X. Wang G.J. Wang 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
NeQuick ionospheric electron density model, which has been developed to version 2, produces the full electron density profile in the ionosphere. Each part of the profile is modeled using Epstein layer formalism. Simple empirical relations are used to compute the thicknesses of each layer. In order to validate the B2bot parameter in the NeQuick model during high solar activity, we use the data at Hainan, China (109.1°E, 19.5°N; Geomagnetic coordinates: 178.95°E, 8.1°N), measured with DPS-4, and study the diurnal and seasonal variations of B2bot, ΔB2 (B2best − B2NeQuick 2) and the seasonal median values of B2best/B2NeQuick 2 at that region. The results show that, (1) The differences between B2best and B2NeQuick 2 have diurnal and seasonal variations. (2) The diurnal variations of B2NeQuick 2 are smaller than those of B2best. (3) Generally, except for early morning the experimental values are properly reproduced. (4) Generally, during morning the NeQuick model has an underestimation. The magnitude of underestimation varies with LT and season. 相似文献
108.
109.
基于F2812的多处理器串行加载系统设计 总被引:1,自引:0,他引:1
阐述了一种基于F2812的多处理器串行加载系统,对加栽系统的工作原理和软件设计进行了详细介绍。系统可实现系统集成环境下多处理器软件代码的在线编程。经过大量测试和环境试验考核,串行加载系统工作稳定可靠。 相似文献
110.