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Inconel 718合金钨极惰性气体保护焊的热循环(英文) 被引量:7
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作者 M.HERNáNDEZ R.R.AMBRIZ +3 位作者 R.CORTéS C.M.GóMORA G.PLASCENCIA D.JARAMILLO 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2019年第3期579-587,共9页
采用热动源模型和瞬态热分析相结合,并借助于有限元方法,确定在Inconel 718合金板上应用钨极惰性气体保护焊获得的焊接热循环和等温截面。Rosenthal厚板模型和有限元分析结果显示,焊接热循环与实验值较相近。与实验曲线相比,用双椭圆模... 采用热动源模型和瞬态热分析相结合,并借助于有限元方法,确定在Inconel 718合金板上应用钨极惰性气体保护焊获得的焊接热循环和等温截面。Rosenthal厚板模型和有限元分析结果显示,焊接热循环与实验值较相近。与实验曲线相比,用双椭圆模型热分布数值模拟确定的等温截面其拟合效果优于高斯模型。为了分析不同冷却速率下熔融区和热影响区显微组织的转变,进行维氏显微硬度测量(由横截面硬度分布曲线和纵截面硬度分布映射图表示)。与基体材料的显微硬度(~350 HV_(0.2))相比,热影响区(~200 HV_(0.2))和熔融区(~240 HV_(0.2))的显微硬度降低,这是由于根据连续冷却转变曲线,γ″相(镍基体)的不均匀溶解过程生成Laves相、δ相和金属间化合物过渡相,使熔融区的硬度值降低。 展开更多
关键词 INCONEL718合金 钨极惰性气体保护焊(GTAW) 焊接热循环 有限元方法 热动源
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Earth observation using radar data:an overview of applications and challenges
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作者 C.Palmanna S.Mavromatis +2 位作者 m.hernandez J.Sequeira B.Brisco 《International Journal of Digital Earth》 SCIE 2008年第2期171-195,共25页
The first pictures of the earth were taken from a balloon in the mid-19^(th) century and thus started‘earth observation’.Aerial missions in the 20^(th) century enabled the build-up of outstanding photographic librar... The first pictures of the earth were taken from a balloon in the mid-19^(th) century and thus started‘earth observation’.Aerial missions in the 20^(th) century enabled the build-up of outstanding photographic libraries and then with Landsat-1,the first civilian satellite launched in 1972,digital images of the earth became an operational reality.The main roles of earth observation have become scientific,economic and strategic,and the role of synthetic aperture radar(SAR)is significant in this overall framework.Radar image exploitation has matured and several operational programs regularly use SAR data for input and numerous applications are being further developed.The technological development of interferometry and polarimetry has helped further develop these radar based applications.This paper highlights this role through a description of actual applications and projects,and concludes with a discussion of some challenges for which SAR systems may provide significant assistance. 展开更多
关键词 remote sensing synthetic aperture radar APPLICATIONS
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