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STUDIES ON THE PRENYLFLAVONOIDS PART X IX SYNTHESIS OF EXIGUAFLAVANONE K

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Chinese Chemical Letters 1996年第1期7卷 11-12页

作者： Xian Yong BU Li XIAO and Yu Lin LI(State Key Laboratory of applied Organic Chemistry and institute of Organic Chemistry, {2. University {2., 730000) State Key Lab. of Appl. Organ Institide Organic Chemistry Lanzhou University Lanzhou 730000

K was first synthesized via the Condensation of 2.hydroxy-3-prenyl-4, 6-dimethoxymethoxyacetophenone 3- methoxy-4methoxymethoxybenzaldehyde followed by cyclixation

关键词： IX STUDIES ON THE PRENYLFLAVONOIDS PART X IX SYNTHESIS OF EXIGUAFLAVANONE K

An exact solution for flow past an accelerated horizontal plate in a rotating fluid with the generalized Oldroyd-B model

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Acta Mechanica Sinica 2009年第4期25卷 463-469页

作者： Jianhong Kang Mingyu Xu institute of applied mathematics,School of mathematics and System Science,Shandong University, 2.0100 Jinan,{2. institute of applied mathematics School of Mathematics and System Science Shandong University 250100 Jinan China

In this paper, the generalized Oldroyd-B with fractional calculus approach is used. An exact solution in terms of Fox-H function for flow past an accelerated horizontal plate in a rotating fluid is obtained by using discrete Laplace transform method. A comparison among the influence of various parameters in the Oldroyd-B model and the angular velocity of the fluid on the velocity profiles is made through numerical method in graphic form.

关键词： Generalized Oldroyd-B model Rotating fluid Accelerated plate Exact solution

MIXED FINITE ELEMENT METHODS FOR A STRONGLYNONLINEAR PARABOLIC PROBLEM

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Journal of Computational mathematics 1999年第2期17卷 209-220页

作者： Yan-ping Chen(Department of mathematics, Nanjing University, Naming 2.0008, china {2. ofComputational and applied mathematics, Xiangtan University, Hunan 411105, china) 南京大学数学系江苏南京

A mixed finite element method is developed to approximate the solution of a strongly nonlinear second-order parabolic problem. The existence and uniqueness of the approximation are demonstrated and L-2.error estimates... 详细信息

关键词： finite element method nonlinear parabolic problem

Variational Iteration Method for Delay Differential Equations

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Communications in Nonlinear Science and Numerical Simulation 1997年第4期2卷 235-236页

作者： Jihuan HE (Shanghai University,Shanghai institute of applied mathematics and Mechanics,Shanghai 2.0 0 0 72.,china) Shanghai University Shanghai Institute of Applied Mathematics and Mechanics Shanghai 200072 China

The variational iteration method is shown to be applicable to delay differential equations for analytical approximate solutions

关键词： Variational Iteration Method for Delay Differential Equations

Theoretical and experimental researches on C-band three-cavity transit-time effect oscillator

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Science china(Physics,Mechanics & Astronomy) 2004年第3期47卷 310-329页

作者： FAN Zhikai1, LIU Qingxiang1, CHEN Daibing1, TAN Jie1 & ZHOU Haijing2.1. institute of applied Electronics, Chinese Academy of Engineering Physics, Mianyang 62.900,{2. 2. institute of applied Physics and Computational mathematics, Beijing 100088,{2. 1. institute of applied Electronics Chinese Academy of Engineering Physics 621900 Mianyang China 2. institute of applied Physics and Computational {2. 100088 Beijing China

The C-band three-cavity transit-time effect oscillator (3C TTTO) is a novel high power microwave device based on the transit-time effect of the three-cavity (3C) resonator. The operational principle of this device is briefly expounded in this paper, and the theoretical and experimental researches on the radial insulation diode, the 3C resonator, the double-gap output cavity and the circular waveguide bevel cut radiation antenna are presented in detail. By using the analytic method, the eigen modes and their field distributions of the 3C resonator are developed, and some basic laws of the transit-time effect are obtained in non-π mode field of the 3C resonator. At last, the experimental results are given. This device generated RF peak power in excess of 400MW with 15ns FWHM, and its beam-wave power conversion efficiency is about 17%.

关键词： C-band, three-cavity (3C) resonator, transit-time effect, high power microwave, oscillator.

Existence of solutions for the dynamic equation of ferrimagnets

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Progress in Natural Science:Materials International 2007年第11期17卷 1279-1283页

作者： Zeng Ming1, Guo Boling2.and Cheng Caozong1(1. College of applied Sciences, Beijing University of Technology, Beijing 10002., china 2. Center for Nonlinear Studies, {2. of applied Physics and Computational mathematics, Beijing 100088, china) College of applied Sciences Beijing University of Technology Beijing 100022 China Center for Nonlinear Studies Institute of Applied Physics and Computational Mathematics Beijing 100088 China

Ferrimagnet is a kind of basic and important multi-sublattice magnet material. It has attracted more and more attention of physicists and mathematicians. Many results of solitons and numerical computations on this topic have appeared. In this article, the dynamic equation for an isotropic ferrimagnet with two non-equivalent sublattices is studied, existence of weak solutions in multi dimension case is proved through the penalized method, the uniqueness and smoothness of the solution in one dimension case are also obtained by the relation between this equation and hyperbolic equation.

关键词： ferrimagnet weak solutions penalized method finite difference method

Analysis of the Theoretical Foundation and Engineering Effect for Air-duct Embankment on the Qinghai-Tibet Railway

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工程科学（英文版） 2007年第2期5卷 153-160页

作者： Jiang Fuqiang~ 1, 2.(1.The Northwest Research institute Co.Ltd of CREC, lanzhou 730000, Gansu,{2. 2.lanzhou jiaotong Universirty, lanzhou 730070, Gansu,{2.)

Based on the corresponding theories of engineering thermodynamics and hydro-dynamics, a careful study is made of the characteristics of air flow in different duct-embedded ways. According to critical Reynolds number, the atmospheric critical velocity of the duct with different diameters, which makes laminar flow different from turbulent flow, is calculated. Given the condition in which a forced flow occurs and the wind strength is larger than the atmospheric pressure gradient along the air-duct, a rational ratio of the length to the diameter is presented. Based on the above theory and field test data on soil temperature and embankment settlement, the advantages and disadvantages are discussed in details of all duct-embedded ways that might affect the stability of embankment.

关键词： Qinghai-Tibet railway air-duct embankment application permafrost engineering

The First Total Synthesis of Five Elegan Type Natural Products

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Chinese Chemical Letters 1997年第7期8卷 595-598页

作者： Jing LI Jiong LAN Zuo Sheng LIU Yu Lin LI(National Laboratory of applied Organic Chemistry and institute of Organic Chemistry,{2. Univerity, {2. 730000) lanzhou UNIV NATL LAB APPL ORGAN CHEM LANZHOU 730000 PEOPLES R CHINA lanzhou UNIV INST ORGAN CHEM LANZHOU 730000 PEOPLES R CHINA

The first total synthesis of five linear diterpenes: eleganolone (1), eleganolone acetate (2., elegandiol (3), eleganonal (4) and epoxyeleganolone (5), was achieved from (E,E)-farnesol (6) via 4 to 6 steps. The key st... 详细信息

关键词： ppm HNMR cm IR EIMS The First Total Synthesis of Five Elegan Type Natural Products MHz

Simulation of nuclei morphologies for binary alloy

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Science china mathematics 2010年第11期53卷 2927-2936页

作者： LI DaMing1, & ZHANG PingWen2.1Department of mathematics, Shanghai jiaotong University, Shanghai 2.02.0,{2. 2.ey Lab of mathematics and applied mathematics, Center for applied Physics and Technology and School of Mathematical Sciences, Peking University, Beijing 100871,{2. 1. Department of mathematics Shanghai Jiaotong University Shanghai 200240 China2. Key Lab of Mathematics and Applied Mathematics Center for Applied Physics and Technology and School of Mathematical Sciences Peking University Beijing 100871 China

We study the critical nuclei morphologies of a binary alloy by the string method. The dynamic equation of the string, connecting the metastable phase (liquid) and stable phase (solid), is governed by Helmholtz free energy for the binary alloy system at a given temperature. The stationary string through the critical nucleus (saddle point) is obtained if the relaxation time of the string is su?ciently large. The critical nucleus radius and energy barrier to nucleation of a pure alloy with isotropic interface energy in two and three dimensions are calculated, which are consistent with the classical nucleation theory. The critical nuclei morphologies are sensitive to the anisotropy strength of interface energy and interface thickness of alloy in two and three dimensions. The critical nucleus and energy barrier to nucleation become smaller if the anisotropy strength of the interface energy is increased, which means that it is much easier to form a stable nucleus if the anisotropy of the interface energy is considered.

关键词： nucleation crystal morphology string method