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1.
讨论高阶演化方程au/at=a(a^2k+1)/(ax^2k+1)(其中a≠0为实常数,k=1,2,3,...)的2层3层显式差分格式,已有格式的精度是O(τ+h)或O(τ+h^2)利用半离散化方法给出一类具有任意阶精度O(τ^p+h^q)(p.q=1.2,...)的显式格式,p=3,4,q=2k.2(k+2)(2层格式)和p=2,4,q=2k,2(k+1).2(k+3)(3层格式)(k=1,2,  相似文献   

2.
本文对于Kuramoto-Tsuzuki方程的混合初边值问题构造了一个广义Box格式,可用追赶法求解。证明了该差分格式是唯一可解的,且当τ=O(h^ε+/4)(ε〉0)时在l2范数下以O(τ^2+h^2)阶收敛。特别可取τ=O(h)。  相似文献   

3.
本文对色散方程ut=auxxx的初边值问题,构造两个绝对稳定的半显式格式,其局部截断 误差为O(τ2+h4+τ2/h2),精度较高.  相似文献   

4.
解KdV方程的一个隐式差分格式   总被引:5,自引:0,他引:5  
对KdV方程ui+uux+Euxxx=0构造了一个二层隐式差分格式,具有三对角线阵,其局部截断误差为O(τ+h+τ/h)其线性化稳定条件为(1+2LQ)^2≥1,L=τ/h,Q=(uTR^n+1+uTR^n+uTR-1^n)/3。数值例子表明,格式长时间稳定,可以描述孤波(Soliton)的性态.  相似文献   

5.
对色散方程ut=auxxx(a为常数,可正可负),本文提出两个在中间层具有六个网格点的三层显式差分格式,其稳定性条件为|r|=|a|τ/h3≤1.25,优于格式的|r|≤1.1815,其局部截断误差仍为 O(τh+h2).  相似文献   

6.
利用待定系数法,建立了解色散方程μt=auxxx的若干蛙跳型对称差分格式,其中稳定性最好的格式稳定性条件是|R|≤3.2470。此外,得到一个高精度蛙跳型对称显格式的截断误差为O(τ^2+h^6),但其稳定性条件仅为|R|≤0.16208。  相似文献   

7.
本文给出了两个解SchrO¨dinger型方程的半显式格式,两格式均能显式计算,且绝对稳定,截断误差为O(τh+τ+h2).  相似文献   

8.
本文对四阶杆振动方程提出两个半显式格式,这些格式都是绝对稳定且可显式地计算,其截断误差均为O(τ/h+τ2+h2).  相似文献   

9.
对四阶抛物型方程Ut+Uxxxx=0提出两类新的三层隐式差分格式,其局部截断误差阶分别为O(Δt2+Δx2)和O(Δt2+Δx4).当参数适当选取时,这些格式都是绝对稳定的且可用追赶法求解.数值例子表明这些格式是有效的.  相似文献   

10.
本给出了两个解SchrOdinger型方程的半显式格式,两格式均能显式计算,且绝对稳定,截断误差为O(τ/h+τ+h^2)。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

13.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

14.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

15.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

16.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

17.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

18.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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