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第二类型含铁地下水除铁研究 被引量:5
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作者 黄宇萍 蔡同辛 《中国给水排水》 CAS CSCD 北大核心 1993年第2期4-7,19,共5页
我国不少地方的地下水属于第二类型含铁地下水。这种水具有特殊的水化学特征,在除铁处理上具有特殊的规律。从实践与理论的角度阐述了第二类型地下水除铁的机理,并从氧化率调控、滤料选择及铝盐除铁等方面介绍了处理的方法。
关键词 地下水 除铁 机理 第二类型
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Complete Spacelike Hypersurfaces with Constant Scalar Curvature in Locally Symmetric Lorentz Spaces
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作者 张士诚 吴报强 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2007年第2期266-275,共10页
The complete space-like hypersurfaces with constant normal saclar curvature is discussed in a locally symmetric Lorentz space. A classified theorem is obtained by the operator L1 introduced by S Y Cheng and S T Yau [3].
关键词 locally symmetric Lorentz space constant saclar curvature space-like hypersurfaces second fundamental form
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Cartan-Fubini type extension of holomorphic maps respecting varieties of minimal rational tangents
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作者 HWANG JunMuk 《Science China Mathematics》 SCIE CSCD 2015年第3期513-518,共6页
A fundamental result in the theory of minimal rational curves on projective manifolds is Cartan- Fubini extension theorem proved by Hwang and Mok, which describes the extensibility of biholomorphisms between connected... A fundamental result in the theory of minimal rational curves on projective manifolds is Cartan- Fubini extension theorem proved by Hwang and Mok, which describes the extensibility of biholomorphisms between connected open subsets of two Fano manifolds of Picard number 1 which preserve varieties of minimal rational tangents (VMRT), under a mild geometric assumption on the second fundamental forms of VMRT's. Hong and Mok have developed Cartan-Fubini extension for non-equidimensional holomorphic immersions from a connected open subset of a Pano manifold of Picard number 1 into a uniruled projective manifold, under the assumptions that the map sends VMRT's onto linear sections of VMRT's and it satisfies a mild geometric condition formulated in terms of second fundamental forms on VMRT's. In the current paper, we give a generalization of Hong and Mok's result, under the same condition on second fundamental forms, assuming only that the holomorphic immersions send VMRT's to VMRT's. Our argument is different from Hong and Mok's and is based on the study of natural foliations on the total family of VMRT's. This gives a substantially simpler proof than Hong and Mok's argument. 展开更多
关键词 varieties of minimal rational tangents extension of holomorphic maps
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