“good”Boussinesq方程的平均向量场方法

提出了利用保能量的平均向量场方法求解"good"Boussinesq方法.首先用Fourier拟谱方法得到半离散的"good"Boussinesq方程,再利用平均向量场方法求解半离散的"good"Boussinesq方程,得到"good"Boussinesq方程的平均向量场格式,然后利用"good"Boussinesq方程的平均向量场格式在不同振幅下对孤立波进行数值模拟.数值结果表明平均向量场格式能很好模拟"good"Boussinesq方程中孤立波行为,能精确保持方程能量守恒特性.     

枝晶生长的傅里叶谱相场模拟

用傅里叶谱方法求解相场模型,并运用该方法对聚合物结晶过程中出现的枝晶生长形态进行数值模拟.通过数值模拟与已有实验结果对比,模拟结果与实验结果基本吻合,验证了傅里叶谱方法求解相场模型的可行性.与有限差分法对比,傅里叶谱方法的运用,简化了对某些运算算子的演化.     

船舶Z形操纵试验的数值模拟

建立三维黏性流数值水池,采用CFD方法对船舶Z形操纵试验进行数值模拟研究.利用重叠网格技术实现船舶航行中的姿态变化,通过求解RANS方程和船舶运动方程,并结合单相Level Set方法,对船舶在开敞水域黏性流场Z形操纵试验进行数值模拟.以"育鲲"轮为对象,数值模拟10°/10°Z形试验.结果表明,计算结果和实船试验数据吻合度较高.     

复杂截面扭转问题的孔洞拟填充法分析

为解决复杂截面应力、变形问题的求解,以柱体扭转问题的应力函数及多连域转化为单连域的方法为基础,应用有限元-边界元法,提出了"孔洞拟填充"的方法,并利用有限元分析软件ANSYS Workbench以偏心轮为例模拟求解扭转问题.结果证明该方法可以适用于任何截面的杆件.     

校正双重介质模拟模型中迭代解的新方法

由于用双重介质模型对裂缝水窜等强非线性渗流问题进行数值模拟时 ,迭代求解往往难以收敛 ,这种不收敛性使得物质平衡误差偏大 ,有时甚至会使模拟失败 .针对这种模拟求解过程中物质平衡误差偏大问题 ,提出了迭代解的物质平衡校正方法 .实际应用表明 ,此方法可以大大降低双重介质模拟模型的物质平衡误差 ,同时还能提高油藏模拟过程中迭代求解的收敛速度     

深亚微米MOSFET的蒙特卡罗快速模拟

用蒙特卡罗-泊松方程自洽求解的方法,对深亚微米金属-氧化物-半导体场效应晶体管--MOSFET的电特性进行了模拟.在泊松方程的求解上,使用了矩阵法,与一般的迭代方法相比,求解速度得到了极大的提高.为减少自散射的次数,用阶梯自散射方案求电子的自由飞行时间.这两个措施的实施,减小了蒙特卡罗模拟时间,加快了模拟速度.模拟中主要考虑了电离杂质、声学形变势、表面粗糙散射和电子谷间散射四种散射机制.模拟的MOSFET输出特性曲线和电子速度在沟道中的分布与报道的相关结果符合得很好.     

大跨度钢结构分步施工模拟方法

针对施工过程中结构几何及边界条件随时间不断变化这一施工力学分析难点,基于先装和后装结构间可通过节点设计构造预夹角的工程实践,提出"生死"子结构先后独立求解、调整"死"结构边界节点转动约束条件的施工模拟方法.分别针对"死"结构为静定和超静定的体系,阐述了两种边界转角条件的调整方法,推导了"生死"子结构的有限元方程,并用该方法对典型算例进行分析、模拟.结果表明,该施工工艺便于后装结构加工且后装结构变形较小,施工完成后结构更接近设计原型.     

武装直升机机体红外辐射数值模拟方法研究

针对武装直升机机体红外辐射的数值计算问题,本文首先在分析蒙皮受热情况的基础上,提出了一种利用区域分解求解机体表面温度分布的方法.该方法将机体分为3个温度区域:一般蒙皮区域,其温度变化通过热网络法求解;发动机热影响蒙皮区域,其温度变化由热源法求解;喷焰加热蒙皮区域,其温度变化由直升机旋翼洗流干扰下的热喷流模拟求解.在此基础上,研究了机体红外辐射的数值模拟方法,包括蒙皮自身辐射的计算和蒙皮反射辐射的计算.最后,应用本文方法,对某型武装直升机的机体红外辐射强度进行了数值模拟,计算结果符合实际分布规律,计算误差在工程精度要求内.该方法已应用于武装直升机红外辐射数值模拟软件中,应用表明该方法稳定、可靠,适于工程分析.     

一种数字模拟电路混联的统一分析法

本文提出了一种数字电路与模拟电路混联的统一分析方法.这种方法主要是采用了数字电路和模拟电路同时变换成函数逻辑求解,因而使得数字模拟VLSI能准确、简单、统一求解.     

容差模拟电路复杂故障的测试与诊断

改进了模拟电路故障参数识别法.对容差模拟电路的复杂故障提出了基于节点电压方程的故障诊断方程,方便了方程的建立.将不可及节点电压作为辅助未知参量,降低了方程的非线性.采用改进的Newton-Raph-son迭代法求解故障诊断方程,加快了求解速度.最后,诊断实例验证了本方法的可行性和有效性.     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Achieving Unusual States of Matter Under High Pressure

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-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

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     

Call for Papers

<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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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