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中国科学：技术科学英文版 2010年第4期53卷 969-975页

作者： HU YanMing1,2 & NIE ChaoQun1 1 Key Laboratory of Advanced Energy and Power Technology,institute of Engineeting Thermophysics,chinese academy of Science,beijing 100190,china 2 Graduate School of chinese academy of sciences,beijing 100190,china 1. Key Laboratory of Advanced Energy and Power Technology Institute of Engineeting Thermophysics Chinese Academy of Science Beijing 100190 China2. Graduate School of Chinese Academy of Sciences Beijing 100190 China

Experimental investigations are performed in a three-stage low-speed axial compressor with variable inlet guide vanes(IGV) and adjustable *** characteristics of the compressor,especially the efficiency and stall margin,are analyzed in design and off-design operation conditions by adjusting stagger angles of IGV and stators as well as changing the rotational *** experimental results show that the off-design performance of the multistage axial compressor is improved by restaggering of IGV and stators related to rotational *** the background of engineering applications,digital signal processing(DSP) technique is used to realize online adjustment of stagger angles according to the corresponding relations between incidence angles of rotor and rotational speed.

关键词： axial compressor IGV surge DSP techniques off-design

Investigation on the skewness for independent component analysis

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Science china(Information sciences) 2011年第4期54卷 849-860页

作者： LIU ZhiYong & QIAO Hong institute of Automation,chinese academy of sciences,beijing 100190,china 1. institute of Automation Chinese Academy of Sciences Beijing 100190 China

Skewness has received much less attention than kurtosis in the independent component analysis (ICA).In particular,the skewness seems to become a useless statistics after the kurtosis related one-bit-matching theorem was ***,as the non-Gaussianity of one signal comes mainly from skewness,it is intuitively understandable that its recovery should not rely on *** this paper we discuss the skewness based ICA,and show that any probability density function (pdf) with non-zero skewness can be employed by ICA for the recovery of the source with non-zero skewness,without needing to consider the skewness *** observation together with the one-bit-matching theorem provides a basic guideline for the model pdf design in ICA algorithm.

关键词： independent component analysis skewness kurtosis one-bit-matching theorem

Remarks on Hard Lefschetz conjectures on Chow groups Dedicated in celebration of SCIENCE china on the occasion of its 60th birthday

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Science china Mathematics 2010年第1期53卷 105-114页

作者： FU BaoHua institute of Mathematics, academy of Mathematic and Systems Science, chinese academy of sciences, beijing 100190, china institute of Mathematics Academy of Mathematic and Systems Science Chinese Academy of Sciences Beijing China

We propose two conjectures of Hard Lefschetz type on Chow groups and prove them for some special cases. For abelian varieties, we show that they are equivalent to the well-known conjectures of Beauville and Murre.

关键词： Chow groups abelian varieties Bloch-Beilinson conjectures Beauville conjecture Murre conjecture

An auto-focus algorithm for imaging of objects under a lossy earth from multi-frequency and multi-monostatic data

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Science china(Information sciences) 2010年第9期53卷 1880-1890页

作者： LIU YanLi1,2,LI LianLin1 & LI Fang1* 1institute of electronics,chinese academy of sciences,beijing 100190,china 2National Science Library,chinese academy of sciences,beijing 100049,china 1. institute of electronics Chinese Academy of Sciences Beijing 100190 China2. National Science Library Chinese Academy of Sciences Beijing 100049 China

The problem of auto-focusing imaging of 2D dielectric objects imbedded in a lossy earth is *** Born approximation,the half-space spectrum Green's function is employed to formulate the half-space imaging algorithm from multi-frequency and multi-monostatic *** the fast Fourier transform can be used to achieve real-time imaging in a very short computing *** the proposed algorithm has avoided the time-consuming regularization of a large-scale ill-posed matrix,the computing time can be greatly cut *** by the principle of time reversed imaging and the minimum entropy criterion,an auto-focusing imaging algorithm is presented to remove the image degradation caused by estimated error of the unknown dielectric parameters of the *** results have shown that the proposed algorithm can provide good quality focused images for both low-contrast and high-contrast targets in a short computing time despite the inaccurate estimation of the earth electric *** proposed algorithm can be extended to three-dimensional case naturally.

关键词： multi-frequency multi-monostatic minimum entropy auto-focusing lossy earth time reversal imaging(TRI)

Markov chain approach to identifying Wiener systems

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Science china(Information sciences) 2012年第5期55卷 1201-1217页

作者： ZHAO WenXiao 1,2 & CHEN HanFu 1,2 1 Key Laboratory of Systems and Control,institute of Systems Science,AMSS,chinese academy of sciences,beijing 100190,china 2 National Center for Mathematics and Interdisciplinary sciences,chinese academy of sciences,beijing 100190,china 1. Key Laboratory of Systems and Control Institute of Systems Science AMSS Chinese Academy of Sciences Beijing 100190 China2. National Center for Mathematics and Interdisciplinary Sciences Chinese Academy of Sciences Beijing 100190 China

Identification of the Wiener system composed of an infinite impulse response (IIR) linear subsystem followed by a static nonlinearity is *** recursive estimates for unknown coefficients of the linear subsystem and for the values of the nonlinear function at any fixed points are given by the stochastic approx-imation algorithms with expanding truncations (SAAWET).With the help of properties of the Markov chain connected with the linear subsystem,all estimates derived in the paper are proved to be strongly *** comparison with the existing results on the topic,the method presented in the paper simplifies the convergence analysis and requires weaker conditions.A numerical example is given,and the simulation results are consistent with the theoretical analysis.

关键词： Wiener system recursive identification stochastic approximation Markov chain strong consis-tency

Holomorphic invariant forms of a bounded domain

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Science china Mathematics 2008年第11期51卷 1945-1964页

作者： LU QiKeng institute of Mathematics, academy of Mathematics and Systems Science, chinese academy of sciences, beijing 100190, china institute of Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

Given a complete ortho-normal system ? = (?0,?1,?2,…) of L 2 H( $ \mathcal{D} $ ), the space of holomorphic and absolutely square integrable functions in the bounded domain $ \mathcal{D} $ of ? n , we construct a holomorphic imbedding $ \iota _\phi :\mathcal{D} \to \mathfrak{F}(n,\infty ) $ , the complex infinite dimensional Grassmann manifold of rank n. It is known that in $ \mathfrak{F}(n,\infty ) $ there are n closed (μ, μ)-forms τμ (μ = 1,…,n) which are invariant under the holomorphic isometric automorphism of $ \mathfrak{F}(n,\infty ) $ and generate algebraically all the harmonic differential forms of $ \mathfrak{F}(n,\infty ) $ . So we obtain in $ \mathcal{D} $ a set of (μ, μ)-forms ι ? * τμ (μ = 1,…, n), which are independent of the system ? chosen and are invariant under the bi-holomorphic transformations of $ \mathcal{D} $ . Especially the differential metric ds 2 1 associated to the K?hler form ι ? * τ1 is a K?hler metric which differs from the Bergman metric ds 2 of $ \mathcal{D} $ in general, but in case that the Bergman metric is an Einstein metric, ds 1 2 differs from ds 2 only by a positive constant factor.

关键词： complete ortho-normal system holomorphic invariant forms 32A36 32A65

The lepton flavor violating signal of the extra gauge boson Z′in photon-photon collision at the ILC

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Science china(Physics,Mechanics & Astronomy) 2010年第11期53卷 1992-1997页

作者： LIU GuoLi 1,2 1 Physics Department,Zhengzhou University,Zhengzhou 450001,china 2 Kavli institute for Theoretical Physics china,chinese academy of sciences,beijing 100190,china 1. Physics Department Zhengzhou University Zhengzhou 450001 China2. Kavli Institute for Theoretical Physics China Chinese Academy of Sciences Beijing 100190 China

The hitherto unconstrained lepton flavor mixings,induced by the new gauge boson Z ,which are the prediction of many new physics models,such as topcolor-assisted technicolor (TC2) models and flavor-universal TC2 models,may lead to the lepton flavor violating productions of τμˉ,τeˉ and μeˉ in photon-photon collision at the proposed International Linear Collider (ILC).Through a comparative analysis of these processes,we find that the better channel to probe the new physics models is the production of τμˉ or τeˉ which occurs at a much higher rate than μeˉ production due to the large mixing angle and the large flavor changing coupling,and may reach the detectable level of the ILC for a large part of the parameter *** the rates predicted by the Standard Model are far below the detectable level,these processes may serve as a sensitive probe for such new physics models.

关键词： new gauge boson Z lepton flavor violating processes photon-photon

High Throughput SNP Genotyping with Two Mini-sequencing Assays

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Acta Biochimica et Biophysica Sinica 2004年第6期36卷 379-384页

作者： Chunqing LUO1,2#, Libin DENG1#, and Changqing ZENG1,2* The institute of Genetic and Developmental Biology, the chinese academy of sciences, beijing 100101, china 2beijing Genomics institute, the chinese academy of sciences, beijing 101300, china The institute of Genetic and Developmental Biology the Chinese Academy of SciencesBeijing 100101 China beijing Genomics institute the Chinese Academy of SciencesBeijing 101300 China

Two mini-sequencing methods, FP-TDI (template-directed dye-terminator incorporation with fluorescence-polarization) and MassArray (matrix assisted laser desorption ionization time of flight detection mass spectrometry), were optimized. A numeric standard was introduced to evaluate the SNP scoring quality of FP-TDI assay, thus made the optimization work easier. At the same time, using multi-PCR technology, 8-plex genotyping of MassArray assay was successfully carried out, some softwares were developed and the data process of MassArray was highly automated. Then these two methods were applied to high throughput SNP genotyping, the accuracy, efficiency and robustness were compared. The result shows FP-TDI is more sensitive to the concentration of SNPprimer and PCR product, as well as extension cycles, the SNPprimer length of FP-TDI should be 24–30 bp long, whereas MassArray assay prefers to be as short as only 16 *** 6440 SNP sites of human chromosome 3 were genotyped in a sample of 90 individuals, 4792 sites by FP-TDI assay and 1648 sites by MassArray assay, the success rates of FP-TDI and MassArray were 67.7% and 93.6% respectively. The throughput of MassArray was higher than FP-TDI, and the cost of MassArray was lower, MassArray was more suitable for high throughput SNP genotyping.

关键词： SNP genotyping FP-TDI MassArray high throughput

MODELLING AND NUMERICAL SOLUTIONS OF A GAUGE PERIODIC TIME DEPENDENT GINZBURG-LANDAU MODEL FOR TYPE-Ⅱ SUPERCONDUCTORS

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Journal of Computational Mathematics 1997年第4期15卷 365-384页

作者： Zhi-ming Chen (institute of Mathematics, chinese academy of sciences, beijing, china) 中科院数学所北京

In this paper we seek the solutions of the time dependent Ginzburg-Landau model for type-Ⅱ superconductors such that the associated physical observables are spatially periodic with respect to some lattice whose basic lattice cell is not necessarily rectangular. After appropriately foring the gange, the model can be formulated as a system of nonlinear parabolic partial differential equations with quasi-periodic boundary conditions. We first give some results concerning the existence, uniqueness and regularity of solutions and then we propose a semiimplicit finite element scheme solving the system of nonlinear partial dmerential equations and show the optimal error estimates both in the L2 and energy *** also report on some numerical results at the end of the paper.

关键词： Math QT MODELLING AND NUMERICAL SOLUTIONS OF A GAUGE PERIODIC TIME DEPENDENT GINZBURG-LANDAU MODEL FOR TYPE SUPERCONDUCTORS

Plastic deformation of nanocrystalline nickel

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Science china(Technological sciences) 2009年第8期52卷 2216-2221页

作者： WU XiaoLei State Key Laboratory of Nonlinear Mechanics, institute of Mechanics, chinese academy of sciences, beijing 100190, china State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China

A high-resolution electron microscopy study has uncovered the plastic behavior of accommodating large strains in nanocrystalline (NC) Ni subject to cold rolling at liquid nitrogen temperature. The activation of grain-boundary-mediated-plasticity is evidenced in NC-Ni, including twinning and formation of stacking fault via partial dislocation slips from the grain boundary. The formation and storage of 60? full dislocations are observed inside NC-grains. The grain/twin boundaries act as the barriers of dislocation slips, leading to dislocation pile-up, severe lattice distortion, and formation of sub-grain boundary. The vicinity of grain/twin boundary is where defects preferentially accumulate and likely the favorable place for onset of plastic deformation. The present results indicate the heterogeneous and multiple natures of accommodating plastic strains in NC-grains.

关键词： nanocrystalline metal plastic deformation deformation twinning dislocation microstructure