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Compositions of heavy minerals in Northeastern china sandlands and provenance analysis

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Science china Earth sciences 2007年第11期50卷 1715-1723页

作者： XIE Jing1,2 & DING ZhongLi1 1 Institute of Geology and Geophysics, chinese academy of sciences, beijing 100029, china 2 Graduate University of chinese academy of sciences, beijing 100049, china Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China

Sand samples deposited since the Last Glacial Maximum (LGM) from the Hulun Buir, Horqin and Otin-dag sandlands were measured for their assemblages of heavy minerals and chemical compositions of detrital garnets and tourmalines. Heavy mineral assemblages of these three sandlands consist mainly of garnet, ilmenite, epidote and minor amphibole and magnetite. Garnets consist mainly of high Mg type-A ones (58% on average), and minor type-B ones. Toumalines are mainly composed of Mg-rich and minor Fe-rich ones. Compared with those of central-southern Mongolia and central Tarim, these three sandlands are derived from the Phanerozoic rocks of the Central Asian Orogenic Belt and the Archean and Paleoprotorozoic basement rocks of the North china Craton. Our results provide direct evidence that the present-day sands may be reworked from LGM ones. Differences of heavy mineral composi-tions occur between the samples of the three sandlands and Taklimakan Desert, indicating that the material of the western arid regions contributes little to the eastern sandlands.

关键词： heavy minerals,provenance,Northeastern china,garnet,tourmaline

Palynological characters of Glycyrrhiza,Glycyrrhizopsis,and Meristotropis(Leguminosae),with special reference to their taxonomic significance

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Journal of Systematics and Evolution 2010年第6期48卷 455-463页

作者： 1,2Lei MENG 2Xiang-Yun ZHU 1(College of Biological sciences,china Agricultural University,beijing 100094,china) 2(Institute of Botany,chinese academy of sciences,beijing 100093,china) (College of Biological sciences China Agricultural University Beijing 100094 China) (Institute of Botany Chinese Academy of Sciences Beijing 100093 China)

The pollen morphology of 11 species of the genus Glycyrrhiza *** one from each of the genera Glycyrrhizopsis Boiss.& *** Meristotropis Fisch.& *** investigated by scanning electron *** pollen morphology,the main differences between Glycyrrhizopsis and Glycyrrhiza are:Glycyrrhizopsis-pollen grains 36.63 × 40.42 μm in size,oblate spheroidal in shape;and Glycyrrhiza-pollen grains 24.47-33.18 × 23.82-31.83 μm in size,prolate spheroidal in *** and Glycyrrhiza should be recognized as two distinct genera based on palynological and morphological *** and Glycyrrhiza are similar in many important palynological and morphological characters,suggesting that the two should be *** Glycyrrhiza,two types of pollen grains,3-lobed-circular or subtriangular in polar view,are found in different species,in accordance with morphological differences in the two groups,shedding light on the classification and evolution of the genus.

关键词： exine sculpture morphological character pollen morphology taxonomic revision.

Simulation of aerodynamic performance affected by vortex generators on blunt trailing-edge airfoils

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Science china(Technological sciences) 2010年第1期53卷 1-7页

作者： YANG Ke1,2,ZHANG Lei1,3 & XU JianZhong1,2 1 Institute of Engineering Thermophysics,chinese academy of sciences,beijing 100190,china 2 Key Laboratory of Wind Energy Utilization,chinese academy of sciences,beijing 100190,china 3 Graduate School of chinese academy of sciences,beijing 100190,china Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing China Key Laboratory of Wind Energy Utilization Chinese Academy of Sciences Beijing China Graduate School of chinese academy of sciences Beijing China

An investigation was carried out by numerical simulation on a wind turbine airfoil and a blunt trailing-edge airfoil with and without vortex generators (VGs), and the performance of the airfoils was analyzed. By the simulation of airfoil DU 91-W2-250 it was verified that the numerical method and model were credible. Based on this airfoil, a new one with a blunt trailing edge of 6% chord was blended by symmetrically adding thickness, and its characteristics curves were obtained through computing at key angles of attack. Additionally, the pressure distribution on blended airfoil was analyzed by comparing to the airfoil without blend. The interaction of streamwise vortices induced by VGs with trailing vortex or separation vortex was considered, followed by the uncovery of how VGs can suppress the boundary layer separation.

关键词： vortex generators airfoil blunt trailing-edge

THE DUAL MIXED METHOD FOR AN UNILATERAL PROBLEM

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Journal of Computational Mathematics 2003年第6期21卷 733-746页

作者： Lie-heng Wang(LSEC, ICMSEC, academy of Mathematics and System sciences, chinese academy of sciences,beijing 100080, china) 中科院数学与系统科学院 LSEC ICMSEC CAS 北京 100080

In this paper, the dual mixed method for an unilateral problem, which is the simplified modelling of scalar function for the friction-free contact problem, is considered. The dual mixed problem is introduced, the existence and uniqeness of the solution of the problem are presented, and error bounds O(h3/4) and O(h3/2) are obtained for the dual mixed finite element approximations of Raviart-Thomas elements for k = 0 and k = 1 respectively.

关键词： Dual Mixed Method Unilateral Problem.

A novel operation mode for spaceborne polarimetric SAR

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Science china(Information sciences) 2011年第4期54卷 884-897页

作者： QI WeiKong 1,2 & YU WeiDong 1 1 Institute of Electronics,chinese academy of sciences,beijing 100190,china 2 Graduate School of chinese academy of sciences,beijing 100039,china Institute of Electronics Chinese Academy of Sciences Beijing China Graduate School of chinese academy of sciences Beijing China

A novel operation mode for spaceborne polarimetric SAR,named polarization space-division adding polarization code-division (PSD-PCD) operation mode,is proposed in this paper through combining polarimetric SAR with elevation digital beam-forming (DBF) on *** a pulse repetition interval the up-chirp LFM sub-pulse is transmitted with horizontal polarization antenna,and with some delay the down-chip LFM subpulse is transmitted with vertical polarization antenna to realize code *** every sub-aperture receives returns from ground,SAR system uses range DBF to separate echoes relative to different sub-pulses in order to realize space *** system PRF is equal to that of single-polarization SAR,and elevation DBF help reduce range ambiguity ***,the main system parameters,including PRF,delay between two sub-pulses,radar equation and ambiguity are analyzed and compared with those of single-polarization *** results demonstrate the feasibility and validity of PSD-PCD operation mode.

关键词： spaceborne synthetic aperture radar (SAR) polarimetry digital beamforming (DBF) operation mode ambiguity ratio polarization space-division polarization code-division

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

Transformations and non-degenerate maps

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Science china Mathematics 2005年第Z1期48卷 195-205页

作者： LI Baokui & WANG Yuefei Institute of Mathematics, academy of Mathematics and System sciences, chinese academy of sciences, beijing 100080, china Graduate School, chinese academy of sciences, beijing 100080, china Institute of Mathematics Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing China Graduate School Chinese Academy of Sciences Beijing China

We shall prove the equivalences of a non-degenerate circle-preserving map and a M(o)bius transformation in ^Rn, of a non-degenerate geodesic-preserving map and an isometry in Hn of a non-degenerate line-preserving map and an affine transformation in Rn. That a map is non-degenerate means that the image of the whole space under the map is not a circle, or geodesic or line respectively. These results hold without either injective or surjective, or even continuous assumptions, which are new and of a fundamental nature in geometry.

关键词： M(o)bius transformation, circle-preserving map, non-degenerate map.

CONVERGENCE OF NONLINEAR CONJUGATE GRADIENT METHODS

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Journal of Computational Mathematics 2001年第5期19卷 539-548页

作者： Yu-hong Dai (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 a study on methods for unconstrained optimization. Assumptions of the study; Main results; Convergence properties of the methods under simplified Armijo-type line search.

关键词： unconstrained optimization conjugate gradient (generalized) line search global convergence

COMPOSITE-STEP LIKE FILTER METHODS FOR EQUALITY CONSTRAINT PROBLEMS

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Journal of Computational Mathematics 2003年第5期21卷 613-624页

作者： Pu-yan Nie(LSEC, ICMSEC, academy of Mathematics and System sciences, chinese academy of sciences, beijing 100080, china) 中科院数学与系统科学院 LSEC ICMSEC CAS 北京 100080

In a composite-step approach, a step Sk is computed as the sum of two components Uk and hk. The normal component Vk, which is called the vertical step, aims to improve the linearized feasibility, while the tangential component hk, which is also called horizontal step, concentrates on reducing a model of the merit functions. As a filter method, it reduces both the infeasibility and the objective function. This is the same property of these two methods. In this paper, one concerns the composite-step like filter approach. That is, a step is tangential component hk if the infeasibility is reduced. Or else, Sk is a composite step composed of normal component Uk, and tangential component hk.

关键词： Composite-step like approaches Filter methods Equality constraints Sequen- tial quadratic programming(SQP) algorithms Normal component Tangential component Convergence.