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Predicting Duct Height in Atmospheric Duct by Neural Network
Advanced Materials Research, 2012The experimental data show that Southeast China Sea has a higher occurrence probability of atmospheric duct. Based on modified refractivity, Neural Network was introduced to predict the duct height of evaporation duct and analyze the anomalous propagation of electromagnetic wave in marine evaporation duct.
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EMI potential of radiowaves in presence of atmospheric ducts
International Journal of Electronics, 1990Radiowave propagation measurements were conducted over a smooth-Earth diffraction path (35 km) between Roorkee and Saharanpur for a period of one year. The data collected were analysed with a view to contribute to the understanding of the propagation phenomenon involved and to provide some physical basis for the prediction techniques to be considered ...
R. K. TEWARI, B. S. JASSAL, M. N. ROY
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The effect of atmospheric ducts on the propagation of AIS signals
Australian Journal of Electrical and Electronics Engineering, 2019Electromagnetic wave propagates abnormally under atmospheric duct conditions. It is very important to study the influence of atmospheric duct on the radio propagation of the shipborne automatic ide...
Wenlong Tang, Hao Cha, Min Wei, Bin Tian
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The operating characteristics of a ducted rocket in the Mars atmosphere
46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, 2010The Mars vehicle which can fly in the Mars atmosphere is necessary to do detailed surveys of the surface of Mars. This vehicle needs a propulsion engine which can work in the Mars atmosphere, mainly consisting of carbon dioxide. The ducted rocket is effective as propulsion engine, because it uses carbon dioxide as an oxidizer and combusts metal as fuel.
Masamichi Ushijima +3 more
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Design of an ocean atmospheric duct signal processor
2010 International Symposium on Intelligent Signal Processing and Communication Systems, 2010The atmospheric refractive section plane retrieved from radar sea clutter is of importance for the might enhancement of military naval radar. In this paper, an atmospheric duct signal processor with hardware of an intermediate-frequency board and a high-speed DSP board, besides the arithmetic of clutter suppression and sea clutter extraction, have been
null Li XueHua +3 more
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Prediction of Electromagnetic Shadow Zone in Atmospheric Duct
The 2006 4th Asia-Pacific Conference on Environmental Electromagnetics, 2006Electromagnetic shadow zone is an important propagation character which is caused by atmospheric duct. The purpose of this paper is to find a method to predict such shadow zone. Two numerical models are introduced in this paper. The first one is used to predict the top hole in evaporation duct. The other one is to predict the skip zone in surface duct.
Jiao Lin, Wang Hua, Zhang Yong-gang
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Trends and frontiers of atmospheric duct research based on CiteSpace and deep learning
Environmental Science and Pollution Research, 2022The research of evaporation duct is of fundamental importance in the radar and signal communication industry. Particularly, in a real atmosphere environment, most of the radar holes cannot be corrected in time because of the persistent evaporation duct phenomenon.
Jiajing, Wu +5 more
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Background covariance of atmospheric duct properties based on ensembles
2015 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), 2015In Refractivity Data Fusion (RDF), the Cartesian representation of refractivity calculated from the Numerical Weather Prediction (NWP) output is mapped into a set of 2-dimensional diagnostic variables which are surfaces over the NWP domain. The diagnostic parameters (e.g. duct base height, duct strength, duct thickness, evaporation duct height) include
Neil D. Gordon +4 more
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Ducted propagation in the atmosphere, from audible sound to infrasound.
The Journal of the Acoustical Society of America, 2010Earth’s atmosphere supports complicated and highly variable winds and temperature gradients. Temperature inversions and wind jets provide ducts in which sound can propagate efficiently to great distances from the source. Due to the intrinsic variability of the atmospheric winds, these sound ducts are also quite variable, both temporally and spatially ...
Roger Waxler +6 more
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Ducted Acoustic Gravity Waves in a Nearly Isothermal Atmosphere
The Journal of the Acoustical Society of America, 1967The propagation of acoustic gravity waves is analyzed in atmospheres that have vertical profiles of sound speed squared of the form c2(z) = c2(∞)±Δc2e−2/l, where c2(∞)≫Δc2>0, and both c2(∞) and Δc2 are constant. Ducted wave dispersion relations are obtained from the requirements that the earth's surface act as a rigid boundary to the atmospheric
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