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一种计算沉积速率的新方法——宇宙尘埃特征元素法 被引量:40
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作者 吴智平 周瑶琪 《沉积学报》 CAS CSCD 北大核心 2000年第3期395-399,共5页
地球每时每刻都在接受宇宙尘埃的沉降 ,且其年沉降量相对稳定 ,加之宇宙尘埃中的Ir、Co等特征元素的平均含量较恒定 ,因此沉积物中宇宙尘埃特征元素Ir、Co的丰度值能够体现出沉积物的沉积速率。当沉积速率较慢时 ,沉积物中宇宙尘埃特征... 地球每时每刻都在接受宇宙尘埃的沉降 ,且其年沉降量相对稳定 ,加之宇宙尘埃中的Ir、Co等特征元素的平均含量较恒定 ,因此沉积物中宇宙尘埃特征元素Ir、Co的丰度值能够体现出沉积物的沉积速率。当沉积速率较慢时 ,沉积物中宇宙尘埃特征元素的丰度值较大 ,反之 ,则较小。本文在前人工作的基础上 ,对利用宇宙尘埃特征元素计算沉积速率的方法和原理进行了探讨 ,并运用该方法对山东临朐N/E界线地层的沉积速率进行了实例研究。与传统方法相比 ,依据宇宙尘埃特征元素在地层中的分布特征计算沉积速率具有更好的实用性和准确性。 展开更多
关键词 沉积速率 宇宙尘埃 沉积学 特征元素法
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工程制图中形体尺寸标注完整性的分析 被引量:2
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作者 薛爱文 杨胜强 《机械管理开发》 2004年第5期7-8,10,共3页
分析形体表面投影特性与图形元素之间的关系,提出了一种“空间元素投影特征识别法”,并从线面分析法角度论证了此法的可行性。
关键词 一般形体 投影特性 尺寸完整性 空间元素投影特征识别
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Comparative analysis of seismic response characteristics of pile-supported structure
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作者 孔德森 李纯洁 +1 位作者 张伟伟 孟庆辉 《Journal of Central South University》 SCIE EI CAS 2010年第6期1370-1375,共6页
In order to analyze the seismic response characteristics of pile-supported structure,a computational model considering pile-soil-structure interaction effect was established by finite element method.Then,numerical imp... In order to analyze the seismic response characteristics of pile-supported structure,a computational model considering pile-soil-structure interaction effect was established by finite element method.Then,numerical implementation was made in time domain.At the same time,a simplified approximation for seismic response analysis of pile-soil-structure system was briefly presented.Furthermore,comparative study was performed for an engineering example.Through comparative analysis,it is shown that the results obtained by the simplified method well agree with those achieved by the finite element method.These results show that spectrum characteristics and intensity of input earthquakes are two important factors that can notablely influence the seismic response characteristics of superstructure.When the input ground motion acceleration amplitude gradually increases from 1 to 4 m/s2,the acceleration of pier top will increase,but it will not be simply proportional to the increase of input acceleration amplitude. 展开更多
关键词 pile-supported structure pile-soil interaction seismic response spectrum characteristics finite element method
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Terahertz band simulations using two different radiative transfer models
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作者 Linjun PAN Daren Lü 《Science China Earth Sciences》 SCIE EI CAS CSCD 2018年第10期1482-1490,共9页
A high-resolution dual-band terahertz(THz) radiometer was designed to measure vertical distributions of chemical elements in the middle atmosphere of the Tibetan Plateau. A forward simulation, which always should be c... A high-resolution dual-band terahertz(THz) radiometer was designed to measure vertical distributions of chemical elements in the middle atmosphere of the Tibetan Plateau. A forward simulation, which always should be conducted firstly for the development of a matching retrieval algorithm, has not been done before. We use two radiative transfer models, ARTS and AM, to simulate the water vapor, ozone and carbon monoxide spectra on the plateau based on the spectral design of the THz radiometer. The emission line characteristics of the three gases in this spectral band are identified. Reasons for the differences in the spectral simulations between the two models are analyzed for individual gases. The impact of several different spectral parameter settings on the simulations are evaluated through a series of sensitivity experiments. This study suggests that the ARTS is more suitable for the development of the THz radiometer retrieval algorithm. An optimal parameter setting of the ARTS for the three elements are given. 展开更多
关键词 Terahertz radiation RADIOMETER Radiative transfer model Spectral simulation PLATEAU
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