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1.
本文提出了一类含二阶导数的适合于求解刚性常微分方程初值问题手数值公式,讨论了这类公式的收敛性和稳定性,得到了相应的收敛性及稳定性定理,并构造了一个单步三阶L的数值公式和一个两步四阶A稳定的数值公式。  相似文献   

2.
术文研究泛函数微分方程数值解的混合算法,给出了收敛性定理及数值例子。  相似文献   

3.
常微分方程初值问题若干数值方法的分析比较   总被引:1,自引:0,他引:1  
讨论了常微分方程初值问题的一些数值方法,导出了若干种数值方法, 如显式Eul er法、隐式Euler法、θ-法、预报-修正法、龙格-库塔法等, 并对这些数值方法进行了分析比较, 最后给出了相应的数值例子.  相似文献   

4.
本文综述了过去四年中,在一阶脉冲偏微分方程理论方面所获得的部分成果。介绍了脉冲偏微分方程的一些基本理论和定性性质,同时还给出了适用这类方程近似解的数值方法。  相似文献   

5.
时滞微分方程真解光滑化的定性分析   总被引:1,自引:0,他引:1  
通过对时滞微分方程作适当扰动使得扰动解充分光滑.讨论了时滞微分方程的真解、扰动方程的真解和它们的数值解之间的关系.得到了时滞微分方程数值解的整体误差与相应扰动方程数值解的整体误差之间的关系.为处理时滞微分方程真解的不光滑性提供了新的途径.  相似文献   

6.
针对中立型微分方程给出了一类数值算法,并得出了其算法新的渐近稳定性充要条件,数值实验表明,该算法对于中立方程是有效的。  相似文献   

7.
讨论随机微分方程的几类数值计算格式,构造了求解非线性随机微分方程隐格式的预估校正算法,并利用这些数值算法进行了数值实验,分析比较了各种格式的平均全局误差.数值结果表明,Euler方法和Milstein方法的显格式和半隐格式的计算精度比隐格式高.  相似文献   

8.
Treanor显式方法是一种求解刚性常微分方程的数值积分法,用它来解刚性方程时仍然存在一些问题。本文对Treanor方法的稳定性进行了分析和讨论,以Treanor方法为基础,采用Richardson外推技巧,构造出一种改进型方法—T-R预估-校正法。分析和计算都表明,与Treanor方法相比,改进的方法具有更大的稳定域,且提高了数值解的精度。它更适合于刚性方程的求解,是数字仿真中一种较好的数值解法。  相似文献   

9.
针对带有一个延迟项的分段连续型微分方程,研究θ-方法的数值散逸性.将两种θ-方法:线性θ-方法和单腿θ-方法应用于试验方程,得到数值解为散逸的充分条件.主要定理显示两种θ-方法具有一致的散逸性结果,且都保持了原方程的散逸性.  相似文献   

10.
Tau方法是一种数值求解偏微分方程的多项式近似解法.运用Tau方法数值求解Volterra积分微分方程,给出误差估计和几个数值算例说明算法的有效性.  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.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
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   

14.
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   

15.
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   

16.
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   

17.
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   

18.
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   

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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