A low order nonconforming anisotropic finite element approximation to parabolic problem

A low order nonconforming finite element is applied to the parabolic problem with anisotropic meshes. Both the semidiscrete and fully discrete forms are studied. Some superclose properties and superconvergence are obtained through some novel approaches and techniques. This research was supported by the National Natural Science Foundation of China under Grant No. 10671184.     

ANISOTROPIC BIQUADRATIC ELEMENT WITH SUPERCLOSE RESULT

The main aim of this paper is to study the convergence of biquadratic finite element forthe second order problem on anisotropic meshes.By using some novel approaches and techniques,theoptimal error estimates are obtained.At the same time,the anisotropic superclose results are alsoachieved.Furthermore,the numerical results are given to demonstrate our theoretical analysis.     

PO Solution for Scattering by the Complex Object Coated with Anisotropic Materials

1 .INTRODUCTIONItisknownthatphysicaloptics(PO)hasbeenwidelyusedinfastpredictionofradarcrosssection (RCS)ofacomplexconductingorcoatedobject.POisadoptedwithoutexceptionamongtheissuedfamouscomputa tionalsoftwareofhigh frequencyEMscatteringbyacomplexobjectsuchasRECOTA[1 ] ,GRECO[2 ,3] ,X PATCH[4] ,whereonlytheisotropiccoatingisconcerned .However,theanisotropiccoatingencoun teredinsomepracticalapplicationsimpelsonetofindthesuitablesolutionforhigh frequencyscatteringbytheobjectcoatedwi…     

基于灰度值数学形态算子处理的各向异性扩散

在各向异性扩散去噪音处理中,目前的正则化方法不能阻止国像边界和角的退化介绍了在非线性扩散方程中应用灰度值侵蚀和渐进正则化尺度的新算法．它能在有效地去噪音的同时保持边界和角的局域性另外在扩散方程离散化中,用形态算于梯度代替中心差商梯度,对于图像中的单像素点的线条．前者不能增强而后者则能有效地增强最后分别给出了两种算法的增强图像的例子。     

地下水在渐变各向异性介质中的渗流速度方程的改进

Darcy定律是地下水动力学的基础公式,也是描述地下水运动状态的基本公式。怎样应用Darcy定律全面而简单的表达地下水在渐变各向异性介质中的流速方程是本文的目的。     

Tuning the magnetic anisotropy in LSMO manganite films through non-magnetic nanoparticles

We report the observation of anomalous magnetic anisotropy driven by nonmagnetic ZrO2 nanoparticles in epitaxial La2/3Sr1/3MnO (LSMO) films grown on LaAlO3 (LAO) substrates. The compressive epitaxial strain imposed by the lattice mismatch of substrate and film is tuned by the density of ZrO2 nanoparticles embedded in the film matrix and affects the magnetic anisotropy as well as the magnetotransport properties. Epitaxial 54 nm thick LSMO thin films with different concentrations of ZrO2 nanoparticles demonstrate anisotropic hysteresis loops concomitant with anisotropic magnetotresistance behavior. The biaxial epitaxial strain, induced by the substrate/film lattice parameter mismatch is partially relaxed by increasing the density of precipitates and they serve as a tuning parameter for the strain state. We interpret our results by a strain-induced interplay of impurity scattering, weak localization and magnetic domain structure.     

Uniaxial compression behavior and spectroscopic properties of energetic 1,1-diamino-2,2-dinitroethylene(FOX-7) crystals from density functional theory calculations

Using dispersion-corrected density functional theory (DFT),we investigate the effect of uniaxial compression on1,1-diamino-2,2-dinitroethene (FOX-7) crystal.Principal and shear stresses along the [100],[010],and [001]orientations exhibit considerable anisotropic compressibility.Raman spectra are complemented by DFT calculations in vibrational modes.Several abnormal pressure-induced changes in selected Raman modes are observed along the [100] orientation.Combined Raman peak shifts with inter/intra-molecular hydrogen bonds and N-H/N-O covalent bonds,the results demonstrate that the spectroscopic variation are associated with the rearrangement of hydrogen-bonded networks of FOX-7 crystal.These findings imply a possible phase transformation or some minor changes in molecular conformation in the pressure regions under uniaxial compression.     

各向异性厚板静力分析新方法

本文提出了一种各向异性厚板静力分析新方法。按照此方法,可以建立含有横向坐标Z的任意高次项的高阶方程,而不需增加基本未知函数的个数。与现有厚板理论相比,本文所述方法具有基本未知函数少、基本方程易于建立、且简单易解、计算结果精度较高等优点。     

基于有限元方法的CF/PTFE复合材料界面应力

经表面改性和未经改性的碳纤维（CF）增强聚四氟乙烯（PTFE）复合材料的弹性强度均随着碳纤维含量的增加而增强．以碳纤维增强聚四氟乙烯（CF／PTFE）复合材料弯曲强度试验结果作为依据，开展CF／PTFE复合材料界面应力的研究工作．采用各向异性等参单元，推导出在平面载荷作用下多层纤维增强复合板的层间应力分布．进一步利用有限元方法对CF／PT—FE复合材料的界面进行应力分析，并得到与试验结果相一致的结论．     

抗弯刚度对盐溶液中DNA构型的影响

作为DNA连续体模型,界面压力下的弹性杆模型被作为研究盐溶液中DNA平衡构型.研究界面牵引力,盐离子浓度的变化和抗弯刚度变化对构型影响.结果显示DNA凝缩主要受界面牵引力和抗弯刚度影响,随着抗弯刚度的变化,DNA将经历从初始构型到凝缩构型的一系列变化,螺旋型构型的出现与实验中观察现象一致.