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钢制焊接管弯头的系数展开法
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作者 彭化龙 《中国井矿盐》 CAS 1990年第5期26-30,共5页
在真空制盐工业的汽、卤管路中,有很多大直径的焊接管弯头,这些管弯头在制作时要经过画展开图这一工序。常用的展开图画法一般都比较麻烦,要花去较长的工时,还要有较好的工作场地,由于作图误差,在组合拼接的时候要耗去一些氧气、电石,... 在真空制盐工业的汽、卤管路中,有很多大直径的焊接管弯头,这些管弯头在制作时要经过画展开图这一工序。常用的展开图画法一般都比较麻烦,要花去较长的工时,还要有较好的工作场地,由于作图误差,在组合拼接的时候要耗去一些氧气、电石,制作出来的弯头度数也就不十分准确了。我矿在画这些管弯头的展开图时,常常采用的是系数法,至今已沿用10多年,事实证明它有很多优点。本文先以下一例介绍其系数的数学过程,然后将各种常用管弯头展开系数列入表中,并略举例说明其用法。 展开更多
关键词 焊接管弯头 系数展开法
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变系数F展开法求解非线性Schrodinger方程的精确解 被引量:1
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作者 曹娜 徐丽阳 尹晓军 《应用数学》 北大核心 2023年第1期161-169,共9页
本文基于变系数F展开法,并借助Mathematica数学软件,求解了水平科氏力作用下Rossby波振幅满足的非线性Schrodinger方程,得到一系列Jacobi椭圆函数解,以及当模数m→1和m→0时由其退化的双曲函数解和三角函数解,并绘制它们的三维图形.扩... 本文基于变系数F展开法,并借助Mathematica数学软件,求解了水平科氏力作用下Rossby波振幅满足的非线性Schrodinger方程,得到一系列Jacobi椭圆函数解,以及当模数m→1和m→0时由其退化的双曲函数解和三角函数解,并绘制它们的三维图形.扩展了变系数F展开法求解非线性偏微分方程的应用范畴.同时也为非线性Schr?dinger方程得到更多形式的精确解. 展开更多
关键词 系数F展开 非线性SCHRODINGER方程 JACOBI椭圆函数解
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New Families of Rational Form Solitary Wave Solutions to (2+1)-Dimensional Broer-Kaup-Kupershmidt System*
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作者 WANGQi CHENYong +1 位作者 LIBiao ZHANGHong-Qing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第5期769-774,共6页
Taking the (2+1)-dimensional Broer-Kaup-Kupershmidt system as a simple example, some families of rational form solitary wave solutions, triangular periodic wave solutions, and rational wave solutions are constructed b... Taking the (2+1)-dimensional Broer-Kaup-Kupershmidt system as a simple example, some families of rational form solitary wave solutions, triangular periodic wave solutions, and rational wave solutions are constructed by using the Riccati equation rational expansion method presented by us. The method can also be applied to solve more nonlinear partial differential equation or equations. 展开更多
关键词 Riccati equation rational expansion method (2+1) -dimensional Broer-Kaup-Kupershmidt system symbolic computation rational form solitary wave solutions
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New Families of Exact Solutions for (2+1)-Dimensional Broer-Kaup System
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作者 ZHAOHong BAICheng-Lin HANJi-Guang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第2期251-256,共6页
Using a further modified extended tanh-function method, rich new families of the exact solutions for the (2+ 1)-dimensional Broer-Kaup (BK) system, comprising the non-traveling wave and coefficient functions' soli... Using a further modified extended tanh-function method, rich new families of the exact solutions for the (2+ 1)-dimensional Broer-Kaup (BK) system, comprising the non-traveling wave and coefficient functions' soliton-like solutions, singular soliton-like solutions, periodic form solutions, are obtained. 展开更多
关键词 further modified extended tanh-function method (2+1)-dimensional Broer-Kaup(BK) system soliton-like solutions periodic form solution
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一种新的热源强度识别的非迭代方法研究 被引量:2
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作者 吴国鹏 徐闯 +1 位作者 李英健 余波 《工程热物理学报》 EI CAS CSCD 北大核心 2020年第9期2233-2240,共8页
本文提出了一种新的非迭代反演方法来识别二维、三维功能梯度材料导热问题的热源强度。首先,基于有限元法计算正问题来获得测点温度信息;其次,通过矩阵变换建立测点温度和待演热源强度之间的关系,从而建立误差函数;最后借助最小二乘法... 本文提出了一种新的非迭代反演方法来识别二维、三维功能梯度材料导热问题的热源强度。首先,基于有限元法计算正问题来获得测点温度信息;其次,通过矩阵变换建立测点温度和待演热源强度之间的关系,从而建立误差函数;最后借助最小二乘法直接反演获得热源强度。为了提高反演结果的抗不适定性,本文采用了奇异值分解和系数展开法。数值算例分别讨论了基函数的选取,测量误差和测点数量对反演结果的影响。数值结果显示,该方法在识别二维、三维功能梯度材料导热问题的热源强度方面具有较高的精度和计算效率。 展开更多
关键词 非迭代反演方 功能梯度材料 热源强度识别 奇异值分解 系数展开法
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Sharma-Tasso-Olver方程的新显式行波解
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作者 王鑫 《数学的实践与认识》 2022年第7期202-207,共6页
借鉴(G'/G)展开法的基本思路,构造了一类变系数G展开法,并借助Mathematica计算软件,对Sharma-Tasso-Olver方程进行了求解,获得了该方程新的显式行波解.事实证明,此类变系数G展开法对于求解非线性微分方程的精确解是行之有效的.
关键词 Sharma-Tasso-Olver方程 系数G展开 显式行波解
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Wave interaction with a two-layer porous breakwater in the presence of step-type bottom
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作者 Saista Tabssum Balaji Ramakrishnan 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2022年第11期36-47,共12页
Oblique wave interaction with a two-layer breakwater consisting of perforated front and back wall in the presence of bottom undulations is analyzed.Wave characteristics are studied in the framework of small-amplitude ... Oblique wave interaction with a two-layer breakwater consisting of perforated front and back wall in the presence of bottom undulations is analyzed.Wave characteristics are studied in the framework of small-amplitude wave theory,and Darcy’s law is used for flow past porous structures.The varying bottom topography spanned over a finite interval connected by two semi-infinite intervals of uniform water depths.Eigenfunction expansion method is used to handle the solution in the regions of uniform bottom and a modified mild-slope equation along with jump conditions is employed for varying bottom topography.Reflection,transmission,and wave energy dissipation coefficients are obtained numerically by applying the matrix method to understand the effects of several physical quantities such as wavenumber,porosity,and angle of incidence.The transmission coefficient reduces significantly and the wave energy dissipation is high for the present model.Also,Bragg scattering is analyzed in the presence of step-type rippled bottom and presented in this paper. 展开更多
关键词 Two-layer porous breakwater Mild-slope equation Bragg resonance Reflection coefficient Transmission coefficient
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The periodic unfolding method for the heat equation in perforated domains 被引量:1
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作者 DONATO Patrizia YANG ZhanYing 《Science China Mathematics》 SCIE CSCD 2016年第5期891-906,共16页
We study the heat equation with non-periodic coefficients in periodically perforated domains with a homogeneous Neumann condition on the holes. Using the time-dependent unfolding method, we obtain some homogenization ... We study the heat equation with non-periodic coefficients in periodically perforated domains with a homogeneous Neumann condition on the holes. Using the time-dependent unfolding method, we obtain some homogenization and corrector results which generalize those by Donato and Nabil(2001). 展开更多
关键词 heat equations perforated domains homogenization correctors periodic unfolding method
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Dynamics of Analytical Matter-Wave Solutions in Three-Dimensional Bose–Einstein Condensates with Two- and Three-Body Interactions
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作者 靳海芹 何俊荣 +2 位作者 梁检处 蔡泽彬 易林 《Communications in Theoretical Physics》 SCIE CAS CSCD 2014年第2期207-213,共7页
Using the F-expansion method we present analytical matter-wave solutions to Bose-Einstein condensates with two- and three-body interactions through the generalized three-dimensional Gross-Pitaevskii equation with time... Using the F-expansion method we present analytical matter-wave solutions to Bose-Einstein condensates with two- and three-body interactions through the generalized three-dimensional Gross-Pitaevskii equation with time- dependent coefficients, for the periodically time-varying interactions and quadratic potential strength. Such solutions exist under certain conditions, and impose constraints on the functions describing potential strength, nonlinearities, and gain (loss). Various shapes of analytical matter-wave solutions which have important applications of physical interest are s^udied in details. 展开更多
关键词 matter-wave solutions Bose-Einstein condensates breathing solitons
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One-dimensional heat equation with discontinuous conductance
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作者 CHEN Zhen-Qing ZILI Mounir 《Science China Mathematics》 SCIE CSCD 2015年第1期97-108,共12页
We study a second-order parabolic equation with divergence form elliptic operator,having a piecewise constant diffusion coefficient with two points of discontinuity.Such partial differential equations appear in the mo... We study a second-order parabolic equation with divergence form elliptic operator,having a piecewise constant diffusion coefficient with two points of discontinuity.Such partial differential equations appear in the modelization of diffusion phenomena in medium consisting of three kinds of materials.Using probabilistic methods,we present an explicit expression of the fundamental solution under certain conditions.We also derive small-time asymptotic expansion of the PDE’s solutions in the general case.The obtained results are directly usable in applications. 展开更多
关键词 stochastic differential equation semimartingale local time strong solution skew Brownian mo-tion heat kernel asymptotic expansion
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