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An iterative wavefront sensing algorithm for high-contrast imaging systems

Research in Astronomy and Astrophysics 2011年第2期11卷 198-204页

作者： Jiang-Pei Dou 1,2,De-Qing Ren 1,2,3 and Yong-Tian Zhu 1,2 1 National Astronomical Observatories/Nanjing Institute of Astronomical Optics & Technology,Chinese academy of sciences,Nanjing 210042,China 2 Key Laboratory of Astronomical Optics & Technology,Nanjing Institute of Astronomical Optics & Technology,Chinese academy of sciences,Nanjing 210042,China 3 Physics & Astronomy department,california State University Northridge,18111 Nordhoff Street,Northridge,california 91330-8268,USA National Astronomical Observatories / Nanjing Institute of Astronomical Optics & Technology Chinese Academy of Sciences Nanjing 210042 China Key Laboratory of Astronomical Optics & Technology Nanjing Institute of Astronomical Optics & Technology Chinese Academy of Sciences Nanjing 210042 China Physics & Astronomy department California State University Northridge 18111 Nordhoff Street Northridge California 91330-8268 USA

Wavefront sensing from multiple focal plane images is a promising technique for high-contrast imaging ***,the wavefront error of an optics system can be properly reconstructed only when it is very *** paper presents an iterative optimization algorithm for the direct measurement of large static wavefront errors from only one focal plane *** first measure the intensity of the pupil image to get the pupil function of the system and acquire the aberrated image on the focal plane with a phase error that will be *** we induce a dynamic phase on the tested pupil function and calculate the associated intensity of the reconstructed image on the focal *** algorithm will then try to minimize the intensity difference between the reconstructed image and the aberrated test image in the focal plane,where the induced phase is a variable of the optimization *** simulation shows that the wavefront of an optical system can theoretically be reconstructed with high precision,which indicates that such an iterative algorithm may be an effective way to perform wavefront sensing for high-contrast imaging systems.

关键词： techniques: image processing -- methods: numerical -- planetarysystems

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Linear EV model with replicate observations on independent variables

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Science China Mathematics 2006年第6期49卷 752-769页

作者： LIU Jixue, ZHANG Sanguo & CHEN Xiru department of Statistics and Finance, University of Science and Technology of China, Hefei 230026, China department of Mathematics, Graduate School of Chinese academy of sciences, Beijing 100049, China department of Statistics and Finance University of Science and Technology of China Hefei China department of Mathematics Graduate School of Chinese Academy of Sciences Beijing China

This paper studies the linear EV model when replicate observations are made only on independent variables. We construct the estimates of regression coefficients and prove the consistency and asymptotic normality under some proper conditions. Results obtained reveal the difference between the case where the independent and dependent variables are observed repeatedly and simultaneously and the case studied in this article.

关键词： linear EV model, consistency, asymptotic normality.

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CONVERGENCE RATES TO TRAVELLING WAVES FOR A RELAXATION MODEL WITH LARGE INITIAL DISTURBANCE

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Acta Mathematica Scientia 2004年第2期24卷 213-227页

作者：张辉赵引川 departmentofMathematics BeijingNormalUniversityBeijing100825China

This paper is concerned with the convergence rates to travelling waves for a relaxation model with general flux functions. Compared with former results in this direction, the main novelty in this paper lies in the fact that the initial disturbance can be chosen large in suitable norm. Our analysis is based on the L^1-stability results obtained by C. Mascia and R. Natalini in [12].

关键词： Convergence rate relaxation travelling waves large initial disturbance

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Bifurcations and Chaos in a Discrete Predator-prey System with Holling Type-IV Functional Response

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Acta Mathematicae Applicatae Sinica 2005年第1期21卷 157-176页

作者： Ji-cai Huang department of Applied Mathematics, College of Science, China Agriculture University academy of Mathematics and Systems Science, Chinese academy of sciences, Beijing 100080, China department of Applied Mathematics College of Science China Agriculture University academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China

A discrete predator-prey system with Holling type-IV functional responseobtained by the Euler method is first investigated. The conditions of existence for foldbifurcation, flip bifurcation and Hopf bifurcation are derived by using the center manifold theoremand bifurcation theory. Furthermore, we give the condition for the occurrence of codimension-twobifurcation called the Bogdanov-Takens bifurcation for fixed points and present approximateexpressions for saddle-node, Hopf and homoclinic bifurcation sets near the Bogdanov-Takensbifurcation point. We also show the existence of degenerated fixed point with codimension three atleast. The numerical simulations, including bifurcation diagrams, phase portraits, and computationof maximum Lyapunov exponents, not only show the consistence with the theoretical analysis but alsoexhibit the rich and complex dynamical behaviors such as the attracting invariant circle,period-doubling bifurcation from period-2,3,4 orbits, interior crisis, intermittency mechanic, andsudden disappearance of chaotic dynamic.

关键词： predator-prey system bifurcations Bogdanov-Takens bifurcation chaos

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Survival and differentiation of transplanted neural stem cells in mice brain with MPTP-induced Parkinson disease

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Acta Pharmacologica Sinica 2003年第12期24卷 18-24页

作者： LI Xue-Kun, GUO An-Chen, ZUO Ping-Ping department of Pharmacology, School of Basic Medicine, Peking Union Medical College & Chinese academy of Medical sciences, Beijing 100005, China department of Pharmacology School of Basic Medicine Peking Union Medical College & Chinese Academy of Medical Sciences 北京 100005

AIM: To determine survival and differentiation of cultured neural stem cells (NSCs) into viable and functional neurons upon transplantation into mice brain of MPTP-induced Parkinson disease (PD). METHODS: Mouse model of PD was established with two subcutaneous (sc) injections of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 40 mg/kg) twice, 16h apart. NSCs isolated from rat embryo midbrain were cultured in clonal density. After labeled with 5-bromo-2’-deoxyuridine (BrdU), the NSCs were transplanted into the uni-or bi-lateral striatum of PD mouse. Tyrosine hydroxylase (TH) immunofluorescence was used to evaluate the toxicity of MPTP on the neural cells in the substantia nigra. Immunohistology and laser confocal microscope were used to detect the survival and differentiation of transplanted NSCs. RESULTS: The cultured NSCs generated neurospheres and differentiated into neuron and astrocyte. It indicated that the cultured NSCs were multipotent and self-renewal in vitro. TH-positive neural cells were

关键词： neural stem cells cell transplantation Parkinson disease cell survival cell differentiation

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A Simulated Test of Algal Influence of Formation and Deposition of Phosphates

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Acta Geologica Sinica(English Edition) 1991年第4期65卷 417-426页

作者： Liu Zhili Liu Xuexian Fan Yigong Zhu Shixin department of Biology, Nanjing University Tianjin Institute of Geology and Mineral Resources,Chinese academy of Geological sciences department of Biology Nan jing University China

This paper deals with a simulated test of biogenic mineralization made with a blue-green alga species,Spirulina platensix. The data in the experiment were recorded by a computerized surveying system. The influ-ence of algae on the accumulation of phosphorus by changing their microenvironment to promote the forma-tion and deposition of phosphate was studied. The results show that the pH value of cultural liquor rose up to 10 and the redox potential (Eh) may dropby 100-200 mV during the algal logarithmic growth stage, and the cultrual liquor was changed into a mediumwith a weakly reducing condition. At the end of the logarithmic growth stage white deposits of Na_2Ca(CO_3)_2·5H_2O and Ca_2Mg (PO_4)_2·2H_2O were formed on the floor of cultural containers. The test presented a wduableevidence for the theory of biogenic mineralization.

关键词： In A Simulated Test of Algal Influence of Formation and Deposition of Phosphates Test

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DOUBLE　SUBSTITUTE　CALIBRATION　FOR　THE　ISOTOPIC　RATIO　MEASUREMENT　AMONG　RARE　EARTH　ELEMENTS

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Chinese Chemical Letters 1996年第5期7卷 499-502页

作者： Teing Lien CHANG (department of Chemistry, Peking University, Beijing 100871)Dun Min ZHAO (Institute of Geology, academy of Geological sciences. Beijing 100037) department of Chemistry Peking University Beijing 100871 Institute of Geology Academy of Geological Sciences Beijing 100037

Abstract: Through the application of the method of double substitute calibration using the true isotopic ratios of cerium and europium of our laboratory standards, the atomic weight of ytterbium has been determined a... 详细信息

关键词： RATIO CALIBRATION DOUBLE EARTH ELEMENTS FOR ISOTOPIC MEASUREMENT RARE AMONG

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Pleonaste in Boxian meteorite

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Chinese Science Bulletin 1998年第19期43卷 1656-1660页

作者： WANG Kuiren and HONG Ji’an department of Earth and Space sciences, University of Science and Technology of China Advanced Research Center for Earth sciences and Astronomy, University of Science and Technology of China, Third World academy of sciences department of Earth and Space sciences University of Science and Technology of China China Advanced Research Center for Earth sciences and Astronomy University of Science and Technology of China Third World Academy of Sciences Hefei China

There are three kinds of occurrence of pleonaste, a rare meteoritic mineral, totally found in Boxian meteorite. They are as the following: (ⅰ) occurring in the inner circle of the chondrule edge, of which a circle texture is composed; (ⅱ) occurring in the state of inclusions, included in an olivine chondrule, with close paragenesis of wadsleyite; (ⅲ) occurring in the state of porphyry. The chondrule in the first occurrence belongs to CA chondrules. The chemical compositions of pleonaste are heterogeneity except for the atomic ratios of Fe/(Mg+Fe), which can be attributed to the following reasons: (ⅰ) they are congenetic minerals; (ⅱ) the heterogeneity of the compositions of the solar clouds in the early states; (ⅲ) the chondrites are the multiple-stage evolution; (ⅳ) the further proof of Boxian meteorite is an unequilibrium common chondrite.

关键词： rare pleonaste in meteorites found genesis.

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The Constrained Solutions of Two Matrix Equations

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Acta Mathematica Sinica,English Series 2002年第4期18卷 671-678页

作者： An Ping LIAO Zhong Zhi BAI department of Mathematics. Hunan University. Changshu, 410082. P. R. China department of Mathematics and Information Science, Changsha University, Changsha 410003. P. R. China academy of Mathematics and System. sciences. Chinese academy of sciences. Beijing 100080. P. R. China State Key Laboratory of Scientific/Engineering Computing. Chinese academy of sciences. Institute of Computational Mathematics and Scientific/Engineering Computing. academy of Mathematics and System sciences. Chinese academy of sciences. P. O. Box 2719. Beijing 100080. P. R. China department of Mathematics Hunan University Changsha P. R. China department of Mathematics and Information sciences Changsha University Changsha P. R. China academy of Mathematics and System sciences Chinese Academy of Sciences Beijing P. R. China State Key Laboratory of Scientific/Engineering Computing Chinese Academy of Sciences Institue of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing P. R. China

We study the symmetric positive semidefinite solution of the matrix equation AX_1A^T + BX_2B^T=C. where A is a given real m×n matrix. B is a given real m×p matrix, and C is a given real m×m matrix, with m, n, p positive integers: and the bisymmetric positive semidefinite solution of the matrix equation D^T XD=C, where D is a given real n×m matrix. C is a given real m×m matrix, with m. n positive integers. By making use of the generalized singular value decomposition, we derive general analytic formulae, and present necessary and sufficient conditions for guaranteeing the existence of these solutions.

关键词： Matrix equation Symmetric positive semidefinite matrix Bisymmetric positive semidefinite matrix

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Two New Oxindole Alkaloids from Ervatamia yunnanensis

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Chinese Chemical Letters 1999年第7期10卷 575-578页

作者： Yang YU Jin Ming GAO Ji Kai LIU(department of Phytochemistry,Kunming Institute of Botany. The Chinese academy of sciences. Kunming 650204) department of Phytochemistry Kunming Institute of Botany Chinese Academy of Sciences Kunming 650204 China

Two new oxindole alkaloids. 17-demethoxy-hydroisorhynchophylline 1 and 17-demethoxy-hydroisorhynchophylline N-oxide 2, have been isolated from the aerial parts of Ervatamin yunnanensis, and their structures were eluci... 详细信息

关键词： Ervatamia yunnanensis Tsiang Apocynaceae oxindole alkaloids

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