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高斯函数参量法及其在山区降水计算中的应用 被引量:7
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作者 张小咏 刘耕年 +1 位作者 李永化 陈正超 《地理研究》 CSCD 北大核心 2008年第3期594-602,共9页
本文根据乌鲁木齐河流域7个雨量站点多年(17~61年)的月平均降水数据的统计规律,提出一种新的、能够同时满足空间维和时间维插值需求的降水分布及降水量计算模型——高斯函数参量化法。该模型根据高斯函数的几何意义和降水分布规律... 本文根据乌鲁木齐河流域7个雨量站点多年(17~61年)的月平均降水数据的统计规律,提出一种新的、能够同时满足空间维和时间维插值需求的降水分布及降水量计算模型——高斯函数参量化法。该模型根据高斯函数的几何意义和降水分布规律,给高斯函数的参数赋予了明确的物理意义,从而把对降水量和分布函数规律的计算转化为对高斯函数少量参数(1~3个)的估计。不仅能够实现山区降水在时间上和空间上的插值,而且能够实现降水量和降水分布函数的相互转换。特别是能解决在高山区降水数据稀缺条件下的降水量和降水分布估计的问题。大大提高了降水数据的可用性。 展开更多
关键词 高斯参量法 山区降水 降水分布函数 乌鲁木齐河流域
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Influence of precipitation on recrystallization texture of AA3104 aluminum alloy
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作者 黄元春 李青 +2 位作者 肖政兵 刘宇 张欢欢 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第10期3683-3688,共6页
The development of the recrystallization texture of the alloy AA3104 was investigated by analysis of orientation distribution functions determined by X-ray diffraction,supported by EBSD local texture analysis.A typic... The development of the recrystallization texture of the alloy AA3104 was investigated by analysis of orientation distribution functions determined by X-ray diffraction,supported by EBSD local texture analysis.A typical β-fiber with nearly 20%Bs orientation {011}211 was detected in the final hot rolled sheet.At the beginning of annealing at 350 ℃,the cube component{001}100 got a sharp increase.TEM results show that the growth of both number and size of precipitation appears to inhibit the advantage of Cube orientation {001}100 notably after annealing at 350 ℃ for 15 min.Finally,it comes out to be a random distributed orientation by full recry stallization. 展开更多
关键词 AA3104 aluminum alloy recrystallization texture PRECIPITATION particle stimulated nucleation(PSN)
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A graded index for evaluating precipitation heterogeneity in China 被引量:1
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作者 刘永林 延军平 +3 位作者 岑敏仪 方群生 刘铮瑶 李英杰 《Journal of Geographical Sciences》 SCIE CSCD 2016年第6期673-693,共21页
Precipitation heterogeneity has a nontrivial influence on human life. Many studies have analyzed precipitation heterogeneity but none have proposed a systematic graded index for its evaluation, and therefore, its true... Precipitation heterogeneity has a nontrivial influence on human life. Many studies have analyzed precipitation heterogeneity but none have proposed a systematic graded index for its evaluation, and therefore, its true characteristics have not been expressed. After comparisons of various methods, the precipitation concentration degree(PCD) method was selected to study precipitation heterogeneity. In addition to the PCD, normal distribution functions, cumulative frequencies, and percentiles were used to establish a graded index for evaluating precipitation heterogeneity. A comprehensive evaluation of precipitation heterogeneity was performed, and its spatiotemporal variation in China from 1960 to 2013 was analyzed. The results indicated that(1) seven categories of precipitation heterogeneity were identified(high centralization, moderate centralization, mild centralization, normal, mild dispersion, moderate dispersion, and high dispersion) and(2) during the study period, the precipitation in more parts of China tended to be normal or dispersed, which is beneficial to human activities. 展开更多
关键词 HETEROGENEITY precipitation concentration degree evaluation index comprehensive evaluation China
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