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排序方式: 共有269条查询结果,搜索用时 31 毫秒
131.
H. Takahashi S. Costa Y. Otsuka K. Shiokawa J.F.G. Monico E. Paula P. Nogueira C.M. Denardini F. Becker-Guedes C.M. Wrasse A.S. Ivo V.C.F. Gomes W. Gargarela Jr. N. Sant’Anna R. Gatto 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
The total electron content (TEC) in the equatorial and low-latitude ionosphere over Brazil was monitored in two dimensions by using 2011 data from the ground-based global navigation satellite system (GNSS) receiver network operated by the Brazilian Institute for Geography and Statistics. It was possible to monitor the spatial and temporal variations in TEC over Brazil continuously during both day and night with a temporal interval of 10 min and a spatial resolution of about 400 km. The daytime equatorial ionization anomaly (EIA) and post-sunset plasma enhancement (PS-EIA) were monitored over an area corresponding to a longitudinal extension of 4000 km in South America. Considerable day-to-day variation was observed in EIA and PS-EIA. A large latitudinal and longitudinal gradient of TEC indicated a significant ionospheric range error in application of the GNSS positioning system. Large-scale plasma bubbles after sunset were also mapped over a wide range. Depletions with longitudinally separated by more than 800 km were observed. They were extended by more than 2000 km along the magnetic field lines and drifted eastward. It is expected that 2-dimensional TEC mapping can serve as a useful tool for diagnosing ionospheric weather, such as temporal and spatial variation in the equatorial plasma trough and crest, and particularly for monitoring the dynamics of plasma bubbles. 相似文献
132.
针对某型飞机给出了DFADS系统的构型描述,进行了DFADS的算法设计,算法采用了一种非物理映射的方法来建立各测压点压力和基本大气参数之间的关系.先是利用制定的多传感器数据表决规则表决出2~3对相关的测压点,然后通过建立相关测压点压力和其压力系数值之间的关系,利用这几对测压点的压力对事先建立的Cpi(α,β,Ma)映射关系表格数据库进行查表计算,从而得到当前的飞行状态.本文利用计算流体动力学(CFD)计算手段获得了332个飞行状态下飞机前机身14个测压点的表面压力系数数据,并以此为基础对DFADS的算法进行了仿真验证.结果表明,该DFADS的算法可以根据14个点的压力输入,正确地解算当前的大气参数. 相似文献
133.
Siyu Tang Zhi Huang Hong Yuan 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(2):722-730
Radial basis function (RBF) interpolation with multi-quadric is developed to perform ionospheric total electron content (TEC) mapping for the Chinese region between 15°N ~ 40°N and 100°E ~ 125°E. TEC measurements from the Centre for Orbit Determination in Europe (CODE) covering the solar maximum year 2011 are used to investigate the performance of the proposed RBF interpolation method. The differences between the RBF interpolated TEC and the CODE TEC are within 0.5 TECU and the root mean square error (RMSE) is very small when 49 data points are used. The maximum difference is ~5 TECU and the error is less than 1 TECU with 25 samples. Our study suggests that a random distribution of measurement points gives smaller RMSEs than a homogenous distribution when the number of sample points is low. The study indicates that RBF interpolation offers a powerful and reliable tool for ionospheric TEC mapping. 相似文献
134.
As an efficient artificial truncating boundary condition, conformal perfectly matched layer (CPML) is a kind of multilayer anisotropic absorbing media. To reduce computing effort of CPML, this article proposes a layer-oriented element integration algorithm. In this algorithm, the relative dielectric constant and permeability are considered as constants for each the very thin monolayer of CPML, and the element integration of multilayer along the normal direction is substituted by the element integration of monolayer. The CPML is divided into multilayer elements, whose element matrixes are evaluated by monolayer integration. Numerical examples show that the layer-oriented element integration algorithm is reliable and the CPML formed with this algorithm possesses high-efficient absorbing performance. 相似文献
135.
Abstract The present work explores an interactive model of spatial and temporal information in map memory. In four experiments, participants learned a map with temporal and spatial information confounded or unconfounded. Attentional and representational levels of information were made apparent through tasks that tap spatial, temporal, or other information. Learning criteria emphasizing sequential order or location imposed differential weighting of the information types in memory. Results indicate that map memory is spatial, but also interacts with the order in which map locations are encountered. Findings show flexibility in allocating attention and information indexing of location and sequential order information in map learning. 相似文献
136.
江慎铭 《南昌航空工业学院学报》2009,23(1):17-21
本文主要在FC-空间内讨论一类截口定理,得到一些存在性定理,这些结果推广和改进了最近一些成果. 相似文献
137.
138.
Mineral mapping in the Kap Simpson complex,central East Greenland,using HyMap and ASTER remote sensing data 总被引:1,自引:0,他引:1
Enton Bedini 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
This research focuses on the application of HyMap airborne hyperspectral data and ASTER satellite multispectral data to mineral exploration and lithologic mapping in the Arctic regions of central East Greenland. The study area is the Kap Simpson complex in central East Greenland. The Kap Simpson complex is one of the largest exposed Palaeogene felsic complexes of East Greenland. It has been the target of several mineral exploration projects. The analysis of the HyMap data produced a detailed picture of the spatial distribution of the alteration minerals in the Kap Simpson complex, unavailable from field-based studies in the area. The analysis of the ASTER data produced mineral maps which due to the moderate spatial and spectral resolution of the ASTER imagery can be useful for reconnaissance level mineral exploration. Colour composites of the mean normalized ASTER thermal bands display lithological information and detected a large felsic igneous intrusion that has not been shown on the recently compiled geological maps of the area. The results of this research have considerable potential to evaluate the use of hyperspectral and multispectral remote sensing for geological purposes in the Arctic regions of central East Greenland. 相似文献
139.
本文将Fuuzy压缩原理进行了推广,首次通过引入一个Fuzzy ε上半连续函数和Fuzzy链空间成功的证明了Fuzzy数值函数的不动点定理。 相似文献
140.