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浅析时轮历中的“三种日”理论 被引量:1
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作者 索郎桑姆 格朗 《西北民族大学学报(哲学社会科学版)》 CSSCI 2014年第6期89-94,共6页
时轮历是藏族天文历算的核心部分,"三种日"理论则是时轮历的基础。从太阳日与太阳的周日视运动、宫年与太阳的周年视运动、太阴月与月亮视运动三个方面论述"三种日"理论所体现的藏族天文历算之天文观,分析该理论所... 时轮历是藏族天文历算的核心部分,"三种日"理论则是时轮历的基础。从太阳日与太阳的周日视运动、宫年与太阳的周年视运动、太阴月与月亮视运动三个方面论述"三种日"理论所体现的藏族天文历算之天文观,分析该理论所体现的以太阳和月亮为典型代表的天体运动规律,根据太阳日、太阴月和宫年之间的关系分析藏历历法中重日、缺日和闰月的设置思想。太阳日与太阴日之间日序的相互配合产生了重日与缺日这种藏历中独有的结构,重日与缺日的积累便形成大小月份,闰月则是按宫月与太阴月的配合关系产生,闰章为65年24闰。 展开更多
关键词 藏族天文历算 时轮历 “三种”理论 天文观 重缺日 闰月
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Reconstruction of a defect in an open waveguide
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作者 BAO Gang TRIKI Faouzi 《Science China Mathematics》 SCIE 2013年第12期2539-2548,共10页
The paper is concerned with the reconstruction of a defect in the core of a two-dimensional open waveguide from the scattering data. Since only a finite numbers of modes can propagate without attenuation inside the co... The paper is concerned with the reconstruction of a defect in the core of a two-dimensional open waveguide from the scattering data. Since only a finite numbers of modes can propagate without attenuation inside the core, the problem is similar to the one-dimensional inverse medium problem. In particular, the inverse problem suffers from a lack of uniqueness and is known to be severely ill-posed. To overcome these difficulties, we consider multi-frequency scattering data. The uniqueness of solution to the inverse problem is established from the far field scattering information over an interval of low frequencies. 展开更多
关键词 inverse problem Helmholtz equation open waveguide Green function multi-frequency data
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