基于Legendre正交矩的三维边界检测算子

提出一种基于Legendre正交矩的新的三维边界检测算子. 通过窗口计算, 该算子可以用来检测三维物体的边界, 并具有比一般其他算子更高的方向灵敏度和表面精度, 同时具有明确的几何模型意义. 计算量是采用矩算子时必须考虑的一个地方. 通过预先计算模板, 可以大大加速计算过程. 我们通过光线跟踪方法将该算子应用于医学图像的绘制当中. 结果表明, 采用Legendre矩的三维边界检测算子, 是一种位置方向计算精度较高的三维边界检测方法.     

一般球对称引力场中的拉普拉斯算子

从三维平直空间中的梯度算子出发,推导出四维弯曲空时中的梯度算子,进而推导出四维弯曲空时中的Laplace算子;作为特例,得到了一般球对称引力场中的Laplace算子.     

船体三维曲板展开方法多目标优化模型

为了有效推进无余量造船的精益造船方法,充分考虑船体三维曲板展开后的板材套料和板材成形等后续工艺环节,基于单元等长展开方法,提出船体三维曲板展开优化模型.以面积误差、边缘线性和平均应变能为目标函数,采用带有启发算子的多目标文化基因算法对船体三维曲板展开优化模型进行求解,基于层次分析法对多组求解所得的方案进行选择,获得最终的展开曲面.通过与测地线法的展开结果进行对比,验证该优化算法的有效性,同时进一步验证了算法中局部搜索算子和启发算子的有效性.     

基于双线性算子计算Boussinesq方程的孤子解

文章通过引入双线性算子,经等价变换得到双线性算子表示下的Boussinesq方程.将幂级数表示的函数代入变换后的方程求得方程的单孤子、双孤子、N孤子以及一般方程的解析解,并用三维图像成功展示了单孤子、双孤子随时间变化的相互作用过程,结果推广了方程的非线性解.Boussinesq方程孤子解析解及其三维显示,有助于对波浪破碎模型和水深变化方程的理解.     

层状介质中三维物体重构的对比源反演算法

对比源反演(CSI)算法将反演问题转化为求解成本泛函的极小值问题,从而形成重构对比源和对比度的迭代序列.开发了一种三维CSI算法对层状介质中的三维物体进行重构,该算法是对二维对比源反演算法的推广.该算法无须正演计算,亦无须人为地选择正则化参数,反演过程更稳定.CSI的每一次迭代过程均采用快速Fourier变换技术计算并矢Green函数算子及其共轭算子,确保了该算法在三维层状介质情况下的高效率.复杂模型的反演结果说明,CSI算法对重构层状介质中的任意三维异常体是非常有效的.     

在频率波数域实现三维叠前深度偏移

叠前深度偏移是理想的改善复杂地区和强横向速度变化的地震资料成像技术,对于复杂变速介质成像,常用的时间域成像方法已不能满足实际需要,必须借助于深度域成像方法,特别是三维地震叠前深度偏移方法.推导了三维叠前深度波场延拓算子公式,指出其实质含义,并通过模型测试进行了验证,介绍了一种三维叠前深度偏移的实现方法,最后进行了偏移算子的误差分析.理论分析与实例计算表明,该计算方法是合理和有效的.     

基于双线性算子计算Boussinesq方程的孤子解

文章通过引入双线性算子,经等价变换得到双线性算子表示下的Boussinesq方程.将幂级数表示的函数代入变换后的方程求得方程的单孤子、双孤子、N孤子以及一般方程的解析解,并用三维图像成功展示了单孤子、双孤子随时间变化的相互作用过程,结果推广了方程的非线性解.Boussinesq方程孤子解析解及其三维显示,有助于对波浪破...     

三维各向同性谐振子的升、降算子

本文利用在粒子数表象中三维各向同性谐振子的升、降算子、推导出在坐标表象中三维各向同性谐振子的升、降算子并求出对三维各向性谐振的三个量子数（N,l,m)的升、降算子。     

变系数三二次长方体有限元解最大模的超逼近

针对某种三维变系数二阶椭圆方程,利用三维投影型插值算子和插值逼近性质获得了长方体剖分下三二次长方体有限元的弱估计,进而结合三维离散Green函数获得了高精度逐点意义下三二次长方体有限元位移及梯度最大模的超逼近.     

油水资源数值模拟中分数步长法和算子分裂法

作者应用计算数学、渗流力学及其理论分析来研究海水入侵和防治、油田勘探和开发中数值模拟的分数步长法和算子分裂法.数学模型是一类耦合非线性偏微分方程组的初边值问题.考虑三维问题大规模科学与工程计算的特征,重点研究三维迎风分数步长差分方法、特征分数步长差分方法和算子分裂特征有限元法及其数值分析.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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