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Planar cubic hybrid hyperbolic polynomial curve and its shape classification

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Progress in Natural Science:Materials International 2004年第1期14卷 42-47页

作者： WANG Guozhao 1,2. * and YANG Qinmin 1,2. (1. Institute of Computer Graphics and Image Processing, 2. department of Mathematics, zhejiang university,{2., china) Institute of Computer Graphics and Image Processing Zhejiang University Hangzhou 310027 China. department of Mathematics Zhejiang University Hangzhou 310027 China

The planar cubic hybrid hyperbolic polynomial curves and cubic H Bézier curves are presented. The conditions leading to inflection points and singularities (cusps and loops) are investigated and the shape of these curves is classified. The conclusions enable us to detect inflection points and singularities and get an idea of how to preserve the fair shape when designing such curves.

关键词： hybrid hyperbolic polynomial curve H-Bézier curve shape classification inflection points singularities

POLYMERIZATION OF γ-STEARYL-α,l-GLUTAMATE N-CARBOXYANHYDRIDE USING RARE earth COORDINATION CATALYSTS

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Chinese Journal of Polymer Science 2000年第4期18卷 369-372页

作者： Xiao-ping Hu Jian Wu Zhi-kang Xu Lin-xian Feng Institute of Polymer Science, zhejiang university, hangzhou 31002.,{2. department of Chemistry, zhejiang university, hangzhou 31002.,{2. 浙江大学浙江杭州

A rare earth coordination system was first investigated as a new type of catalyst for the ring-openingpolymerization of α-amino acid N-carboxyanhydrides (NCAs). The results for the polymerization of γ-stearyl-α,L-glutamate(SLG) NCA using neodymium acetylacetonate (Nd(acac)_3)- or neodymium tris(2.ethylhexylphosphonate) (Nd(P_(2.4))_3)-triethylaluminum-water as catalysts were compared with those using conventional catalysts. It was found that the helicalpoly(γ-stearyl-L-glutamate) with high molecular weight as well as narrow molecular weight distribution can be obtained inthe presence of Nd(acac)_3/AlEt_3-1/2._2.. The polymer obtained was characterized by IR and NMR spectroscopy.

关键词： Rare earth coordination catalyst Ring-opening polymerization Polypeptide Poly(γ-stearyl-α,L-glutamate)

Derivation of Martin-Hou Equation of State from Hard-particle Perturbation Theory

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Chemical Research in Chinese Universities 2000年第1期16卷 49-56页

作者： ZHANG Bing-jian (department of Chemistry, zhejiang university,{2., P. R. china) HOU Yu-chun (department of Chemical Engineering, zhejiang university,{2., P. R. china) 浙江大学浙江杭州 310027

In this paper, the Martin-Hou equation of state is derived by using a power series representation of radial distribution function and an analytic representation of multi-section potential based on the Barker-Henderson hard-particle perturbation theory including high-order terms. In the derivation, a theoretical form of Martin-Hou equation was obtained. It had a similar form and the same capability to predict P-V-T properties as the Martin-Hou equation and no additional data were required for evaluating the constants. The characteristic constants of the theoretical expression have certain relationships with the molecular parameters.

关键词： Perturbation theory Martin-Hou equation of state Theoretical expression P-V-T properties Molecular parameter

Paleomagnetic results of the Cretaceous marine sediments in Tongyouluke, southwest Tarim

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Science china earth {2. 2005年第3期48卷 406-416页

作者： SHEN Zhongyue1, CHEN Hanlin1, FANG Dajun1, DING Jinghai1, ZHANG Shiben2. HUANG Zhibin2.& LI Meng2.1. department of earth {2., zhejiang university, hangzhou 31002. china 2. Tarim Oil Field Company, Petrochina Company Limited, Korla 830011, china department of earth {2. Zhejiang University Hangzhou China Tarim Oil Field Company PetroChina Company Limited Korla China

Paleomagnetic and rock magnetic studies on samples of 18 sites from the Creta- ceous marine sedimentary rocks in the Tongyouluke section, Akto County, southwest Tarim, china show that the magnetic carriers of the Lower Cretaceous are dominated by hematite with some magnetite, while the magnetic carriers of the Upper Cretaceous are characterized by a combination of magnetite and titanomagnetite as well as hematite and goethite. Stepwise thermal demagnetization is performed and vector analysis is used to isolate magnetic components, which illustrates a single magnetic component or double magnetic components. The high temperature stable components are dual polarities and pass polarity test, reversal test and consistency test. The overall mean direction of the Lower Cretaceous is D = 2..0°, I = 42.0°, α95=6.5° with pole position at φ = 190.3°, λ=63.1°, dp=4.9°, dm=8.0°. The overall mean direction of the Upper Cretaceous is D = 2..1°, I = 39.4°, α95=11.2. with pole position at φ =190.9°, λ=60.3°, dp= 8.0°, dm=13.4°. Compared with the inclination of the Early Cretaceous from red beds of north Tarim, the contemporary inclination of southwest Tarim is 10.0°±7.8° sharper, but it is still 8.1° ±8.9°, shallower than that of Early Cretaceous basalts in southwest Tarim. Although these pa- leomagnetic data show slightly larger confidence limit, the paleolatitude of the marine Cretaceous tends to lie between that of terrestrial red beds and volcanic rocks.

关键词： Tarim paleomagnetism, Cretaceous, magnetic inclination, red beds, marine sedimentary rock.

On a class of weak Landsberg metrics

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Science china Mathematics 2007年第4期50卷 573-589页

作者： Ben-ling LI & Zhong-min SHEN department of Mathematics, zhejiang university,{2., china department of Mathematical sciences, Indiana university Purdue university Indianapolis (IUPUI), 402.N. Blackford Street, Indianapolis, IN 462.2.32.6, USA Center of Mathematical sciences, zhejiang university,{2., china department of Mathematics Zhejiang University Hangzhou China department of Mathematical sciences Indiana University Purdue University Indianapolis (IUPUI) Indianapolis USA Center of Mathematical sciences Zhejiang University Hangzhou China

In this paper, we discuss a class of Finsler metrics defined by a Riemannian metric and a 1-form on a manifold. We characterize weak Landsberg metrics in this class and show that there exist weak Landsberg metrics whi... 详细信息

关键词： Finsler metric weak Landsberg metric (α,β)-metric 53B40

Rotationally symmetric translating soliton of H^k-flow

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Science china Mathematics 2010年第4期53卷 1011-1016页

作者： SHENG WeiMin & WU Chao department of Mathematics,zhejiang {2.,hangzhou 31002.,china department of Mathematics Zhejiang University

This paper mainly considers the translating soliton of H k-flow for k > *** give the asymptotic expression of the entire rotationally symmetric translating soliton,and obtain non-convex 'Wing-like' solution as well as... 详细信息

关键词： H k-flow translating soliton 'Wing-like' solution

K-Functional, Weighted Moduli of Smoothness, and Best Weighted Polynomial Approximation on a Simplex

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Acta Mathematica Sinica,English Series 1999年第3期15卷 395-403,405-406页

作者： Song Li department of Mathematics, zhejiang university,{2., P. R. china department of Mathematics Zhejiang University Hangzhou P. R. China

An inverse theorem for the best weighted polynomial approximation of a function in Lwαp（S） is established. We also investigate Besov spaces generated by Freud weight and their connection with algebraic polynomial approximation in Lp（R）wλ, where wα is a Jacobi-type weight on S, 0λ is a Freud weight. For Ditzian-Totik K-functionals on LP（S）, 1≤P≤∞, we obtain a new equivalence expression.

关键词： Weighted moduli of smoothness K-functional Best weighted polynomial approximation Simplex

Geochronology, Geochemistry and Its Tectonic Significance of Chahe Granites in Hainan Island

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Journal of earth Science 2013年第4期24卷 619-625页

作者：唐立梅陈汉林董传万初凤友 Key Laboratory of Submarine Geosciences Second Institute of OceanographyState Oceanic Administration department of earth {2. Zhejiang University

There are very few studies on the granites formed in Late Permian in Hainan （海南） Island. Petrology, geochronology and geochemistry research on Late Permian granites in Chahe （叉河） area, Hainan Island will be reported in this article. The results show that, Chahe granites formed in 2.1 Ma, are riched in SiO2. alkali, Fe2.3 while depleted in MgO and CaO, with low Sr and high Yb, and have all the features consistent with A-type granite. The forming of Chahe granites may suggest that Hainan Island was already in post-orogenic setting in Late Permian.

关键词： granite U-Pb age dating geochemistry Hainan Island.

Characteristics of fMRI BOLD signal and its neurophysiological mechanism

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Progress in Natural Science:Materials International 2007年第6期17卷 630-638页

作者： Zhao Xiaohu1,2. Wu Yigen3 and Guo Shengli3(1. College of Life sciences, zhejiang university, {2. 310058, china 2. Imaging department of Tongji Hospital of Tongji university, Shanghai 2.0065, china 3. College of Mathematics and Physics, Nanjing university of Information Science and Technology, Nanjing 2.0044, china) College of Life sciences Zhejiang University Hangzhou 310058 China Imaging department of Tongji Hospital of Tongji university Shanghai 200065 China College of Mathematics and Physics Nanjing University of Information Science and Technology Nanjing 210044 China

The functional magnetic resonance imaging (fMRI) based on blood oxygen level dependent (BOLD) contrast has emerged as one of the most potent noninvasive tools for mapping brain function and has been widely used to explore physiological, pathological changes and mental activity in the brain. Exploring the nature and property of BOLD signal has recently attracted more attentions. Despite that great progress has been made in investigation of the characteristics and neurophysiological basis, the exact nature of BOLD signal remains unclear. In this paper we discuss the characteristics of BOLD signals, the nonlinear BOLD response to external stimuli and the relation between BOLD signals and neural electrophysiological recordings. Furthermore, we develop our new opinions regarding nonlinear BOLD response and make some perspectives on future study.

关键词： functional magnetic resonance imaging blood oxygen level dependent nonlinear response neural electrophysiological activity.