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Oceanic lithosphere heterogeneity in the eastern Paleo-Tethys revealed by PGE and Re-Os isotopes of mantle peridotites in the Jinshajiang ophiolite

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Geoscience Frontiers 2021年第3期12卷 416-427页

作者： Yan-JunWang Wen-Jun Hu Hong zhong Wei-Guang Zhu zhong-Jie bai State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China Department of Earth Sciences The University of Hong KongHong KongChina College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

Platinum group elements(PGE)and Re-Os isotopes of mantle peridotites in the Jinshajiang ophiolite(SW China)were investigated in this study,in order to constrain the evolution of the lithospheric mantle beneath the Jinshajiang-Ailaoshan Ocean,which was a branch of the eastern *** Jinshajiang peridotites have whole-rock compositions(e.g.,MgO=32.7-38.1 wt.%;Al_(2)O_(3)=0.67-1.30 wt.%)and spinels with moderate Cr#values(0.4-0.6)similar to those of abyssal peridotites,which indicate moderate degrees of partial melting(15%-20%).These peridotites exhibit U-shaped chondrite-normalized REE patterns that could be caused by hydrothermal alteration or melt-rock interaction after mantle *** addition,Pd concentrations and(Pd/Ir)_(N)ratios of the Jinshajiang peridotites increases with decreasing Al_(2)O_(3) *** negative correlations cannot be explained by simple partial melting but record a melt-rock reaction event after mantle *** study therefore demonstrates the efficiency of PGE in detecting the melt-rock reaction process relative to whole-rock major and trace *** suprachondritic^(187)Os/^(188)Os ratios(0.1272-0.1374)further indicate that the later percolating melt derived from a mantle domain with distinct^(187)Os-enriched isotopic *** comparison with peridotites in the Ailaoshan ophiolite belt,which were not significantly affected by melt percolation,this study further highlights that the lithospheric mantle compositions beneath different segments of the same ocean basin are highly variable and might be controlled by distinct mantle processes in response to different rifting mechanisms.

关键词： Jinshajiang ophiolite Paleo-Tethys Mantle peridotites Melt-rock reaction

BLOCK-TRIANGULAR PRECONDITIONERS FOR SYSTEMS ARISING FROM EDGE-PRESERVING IMAGE RESTORATION

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Journal of Computational Mathematics 2010年第6期28卷 848-863页

作者： zhong-Zhi bai Yu-Mei Huang Michael K. Ng LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China School of Mathematics and Statistics Lanzhou University Lanzhou 730000 China Department of Mathematics Hong Kong Baptist University Kowloon Tong Hong Kong

Signal and image restoration problems are often solved by minimizing a cost function consisting of an l2 data-fidelity term and a regularization term. We consider a class of convex and edge-preserving regularization functions. In specific, half-quadratic regularization as a fixed-point iteration method is usually employed to solve this problem. The main aim of this paper is to solve the above-described signal and image restoration problems with the half-quadratic regularization technique by making use of the Newton method. At each iteration of the Newton method, the Newton equation is a structured system of linear equations of a symmetric positive definite coefficient matrix, and may be efficiently solved by the preconditioned conjugate gradient method accelerated with the modified block SSOR preconditioner. Our experimental results show that the modified block-SSOR preconditioned conjugate gradient method is feasible and effective for further improving the numerical performance of the half-quadratic regularization approach.

关键词： Block system of equations Matrix preconditioner Edge-preserving Image restoration Half-quadratic regularization.

Forces Driving Changes in Cultivated Land and Management Countermeasures in the Three Gorges Reservoir Area,China

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Journal of Mountain Science 2013年第1期10卷 149-162页

作者： CAO Yin-gui bai zhong-ke ZHOU Wei WANG Jing School of Land Science and Technology China University of Geosciences Key Laboratory of Land Reconsolidation and Rehabilitation Ministry of Land and Resources Key Laboratory of Land Use Ministry of Land and Resources

The Three Gorges project accelerates economic development in the Three Gorges Reservoir *** paper aimed to investigate the distribution,changes and features of cultivated land in this area,analyze the forces driving the changes in cultivated land area,and propose the countermeasures for cultivated land *** matrix was used to analyze the features of cultivated land changes,and quantitative analysis and qualitative analysis were adopted to research the driving forces according to the features of cultivated land *** land in the Three Gorges Reservoir Area mainly lay to the northwest of the Yangtze River,especially the upper *** areas of cultivated land increased from 1996 to 1999,then decreased from 2000 to 2006,and finally increased again from 2007 to *** important forces driving changes in cultivated land included government policies,employment and food security,increasing construction land,agriculture structure adjustment,land rearrangement,*** cultivated land management,firstly,it is necessary to insist on the principle of cultivated land protection,standardize land exploitation and strictly restrict the transformation of cultivated land into non-farming ***,land rearrangement must be implemented,which can not only increase the area of the cultivated land,but also improve the quality of the cultivated ***,it is feasible to intensify eco-agriculture construction to increase the quantity and quality of cultivated ***,it is helpful to improve the traditional agriculture production methods to promote cultivated land ***,it is important to propagandize cultivated land protection and realize the enormous pressure of cultivated land shortage,making more people obligated to protect cultivated land.

关键词： Land use change Driving force Management countermeasure Cultivated land Three Gorges Reservoir Area

Melting geodynamics reveals a subduction origin for the Purang ophiolite,Tibet,China

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Acta Geochimica 2024年第4期43卷 754-773页

作者： Tao Ruan zhong-Jie bai Wei-Guang Zhu Shi-Ji Zheng State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China University of Chinese Academy of Sciences Beijing 100049China

The debate regarding whether the Yarlung-Zangbo ophiolite(YZO)on the south of the Qinghai-Tibet Plateau,formed in a mid-ocean ridge(MOR)or a supra-subduction zone(SSZ)setting has remained *** we present petrological,mineralogical,and geochemical data associated with modeling melting geodynamics of the mantle peridotites from the Purang ophiolite in the western segment of the Yarlung-Zangbo Suture Zone(YZSZ)to explore its tectonic *** Purang lherzolites are characterized by the protogranular texture and have abyssal-peridotite-like mineral compositions,including low Cr^(#)(20-30)and TiO_(2) contents(<0.1wt%)in spinel,high Al_(2)O_(3)(2.9wt%-4.4wt%)and CaO(1.9wt%-3.7wt%)contents in orthopyroxene and LREE-depletion in *** of these lherzolites can be modeled by~11%dynamic melting of the DMM source with a small fraction of melt(~0.5%)entrapped within the source,a similar melting process to typical abyssal *** Purang harzburgites are characterized by the porphyroclastic texture and exhibit highly refractory mineral compositions such as high spinel Cr^(#)(40-68),low orthopyroxene Al_(2)O_(3)(<2.2wt%)and CaO(<1.1wt%)*** in these harzburgites are enriched in Sr(up to 6.0 ppm)and LREE[(Ce)N=0.02-0.4],but depleted in Ti(200 ppm,on average)and HREE[(Yb)N<2].Importantly,the more depleted samples tend to have higher clinopyroxene Sr and LREE *** observations indicate an open-system hydrous melting with a continuous influx of slab fluid at a subduction *** modeled results show that these harzburgites could be formed by 19%-23%hydrous melting with the supply rate of slab fluid at 0.1%-1%.The lower clinopyroxene V/Sc ratios in harzburgites than those in lherzolites suggest a high oxidation stage of the melting system of harzburgites,which is consistent with a hydrous melting environment for these *** is therefore concluded that the Purang ophiolite has experienced a transformat

关键词： Melting geodynamics SSZ peridotites MOR peridotites Clinopyroxene Purang ophiolite

A SHIFT-SPLITTING PRECONDITIONER FOR NON-HERMITIAN POSITIVE DEFINITE MATRICES

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Journal of Computational Mathematics 2006年第4期24卷 539-552页

作者： zhong-zhi bai Jun-feng Yin Yang-feng Su LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China Department of Mathematics Fudan University Shanghai 200433 China

A shift splitting concept is introduced and, correspondingly, a shift-splitting iteration scheme and a shift-splitting preconditioner are presented, for solving the large sparse system of linear equations of which the coefficient matrix is an ill-conditioned non-Hermitian positive definite matrix. The convergence property of the shift-splitting iteration method and the eigenvalue distribution of the shift-splitting preconditioned matrix are discussed in depth, and the best possible choice of the shift is investigated in detail. Numerical computations show that the shift-splitting preconditioner can induce accurate, robust and effective preconditioned Krylov subspace iteration methods for solving the large sparse non-Hermitian positive definite systems of linear equations.

关键词： Non-Hermitian positive definite matrix Matrix splitting Preconditioning Krylov subspace method Convergence.

Measuring fiber position errors from spectral data

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Research in Astronomy and Astrophysics 2015年第4期15卷 608-616页

作者： Jian-Jun Chen zhong-Rui bai A-Li Luo Yong-Heng Zhao National Astronomical Observatories Chinese Academy of Sciences Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of Sciences University of Chinese Academy of Sciences

Precise fiber positioning is crucial to a wide field, multi-fiber spectroscopic survey such as the Guoshoujing Telescope （the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, LAMOST）. are based on CCD photographic and Nowadays, most position error measurements image processing techniques. These methods only work for measuring errors orthogonal to the telescope optical axis, but there are also errors that lie parallel to the optical axis of the telescope, such as defocusing, and errors caused by the existing deviation angle between the optical axes of a fiber and the telescope. Directly measuring the two latter types of position errors is difficult for an individual fiber, especially during observations. Possible sources of fiber position errors are discussed in brief for LAMOST. By constructing a model of magnitude loss due to the fiber position error for a point source, we propose an indirect method to calculate both the total and systematic position errors for each individual fiber from spectral data. Restrictions and applications of this method are also discussed.

关键词： techniques: multi-fiber -- fiber spectroscopy -- spectrophotometry

Synthesis of Novel 3-Aryl Isoindolinone Derivatives

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Chemical Research in Chinese Universities 2013年第3期29卷 487-494页

作者： HU Chen-ming ZHENG Lian-you PEI Ya-zhong bai Xu Center for Combinatorial Chemistry and Drug Discovery College of Chemistry and School of Pharmaceutical Sciences Jilin University Changchun 130021 P. R. China

A library of novel 3-aryl isoindolinone derivatives with aromatic amino acid derivative fragments was designed and synthesized. Two synthetic routes were employed to construct 3-aryl isoindolinone ring system for diff... 详细信息

关键词： Molecular library 3-Aryl isoindolinone Aromatic amino acid derivative

Study of Soil Seed Banks in Antaibao Opencast Mine

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Journal of China University of Mining and Technology 2006年第3期16卷 333-337页

作者： HAN Li-jun bai zhong-ke LI Jin-chuan College of Resource ＆ Environmental Science Shanxi Agricultural University Taigu Shanxi 030801 China Department of Land Science Technique China University ofGeosciences Beijing 100083 China Institute of Biology in Shanxi Taiyuan Shanxi 030006 China

A seed germinating method was used to study soil seed banks in dump sites of the Antaibao opencast mine for soil reclamation and ecological rehabilitation. Based on a richness index, a diversity index and an evenness index, the diversity of species of soil seed banks was studied. As well, the progress of vegetation succession in this thoroughly destroyed ecosystem is discussed and the self-renewal ability of the soil seed banks is analyzed. The results indicate that 1） there are 17 plant species belonging to five families with annuals as the dominant species; 2） the soil seed banks at the dump site show great temporal and spatial heterogeneity and 3） the model of Robinia pseudoacacia x Pinus tabulaeformis × Caragana korshinskii in the anaphase is the best among several reclamation models studied. Therefore, with the extension of reclamation time, the correct choice of a reclamation model is quite helpful for the improvement of the self-renewal ability of soil seed banks and for the stability of the ecosystem, which is very important for land reclamation and ecological rehabilitation of the dump sites of the ATB opencast coal mine.

关键词： dump of Antaibao opencast mine re-vegetation soil seed bank species diversity

A CLASS OF NEW PARALLEL HYBRID ALGEBRAIC MULTILEVEL ITERATIONS

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Journal of Computational Mathematics 2001年第6期19卷 651-672页

作者： zhong-zhi bai (LSEC ICMSEC, Academy of Mathematics and Systems Sciences, Chinese Academy of Sciences, Beijing 100080, China) 中科院计算数学与科学工程计算所北京 100080

Presents preconditioning matrices having parallel computing function for the coefficient matrix and a class of parallel hybrid algebraic multilevel iteration methods for solving linear equations. Solution to elliptic ... 详细信息

关键词： elliptic boundary value problem system of linear equations symmetric positive definite matrix multilevel iteration parallel method