约束值域广义多项式最佳一致逼近的强唯一性问题

本文在许树声给出的一般情形下约束值域广义多项式最佳一致逼近的特征定理的基础上,建立起了该情形下最佳一致逼近的强唯一性定理及最佳逼近算子在 C(?)的一个子集上的连续性定理。     

约束值域广义多项式最佳一致逼近的强唯一性

本文在许树声给出的一般情形下约束值域广义多项式最佳一致逼近的特征定理的基础上,建立起该情形下最佳一致逼近的强唯一性定理及最佳逼近算子在C(?)的一个子集上的连续性定理.     

变形L非线性逼近

§1.引 言 众所周知,L~p逼近与一致逼近理论有许多区别,在L~p范数下最佳逼近元特征不具有交错性。文献提出了两种L~p范数的变形度量,并证明了在两种度量下,最佳线性逼近元特征具有交错性。然而这两种度量都不是范数,史应光给出了连续函数的一种L变形范数,并且建立了经典线性Chebyshev理论的几乎所有结果。文献讨论了在变形L范数下普通     

非线性同时Chebyshev逼近的存在性和特征

本文主要研究了实连续函数空间C(Ω)中的非线性最佳同时Chebyshev逼近问题,得到最佳同时Chebyshev逼近的存在性定理、Kolmogorov型的特征定理以及Chebyshev型的交错定理.文章最后还给出了具体函数空间中的应用.对有理函数以及指数和函数得到了一系列推论.     

子阵约束下实矩阵反问题的最小二乘解

提出了子阵约束下实矩阵反问题的最小二乘问题,给出了解的表达式．考虑了解集合对给定矩阵的最佳逼近问题,证明了最佳逼近问题解的存在性与唯一性,给出了求最佳逼近解的数值方法．将所得结果应用于解决子阵约束下实矩阵特征反问题．     

拉普拉斯级数的部分和

讨论了拉普拉斯级数的部分的一致逼近。通过估计瓦勒普山和逼近度，建立了部分和算子收敛度的最佳逼近估计，其估计式主最佳Ｌｐ逼近，改进了经典的勒贝格型估计，证明在某种情形下其估计式是最好可能的。     

摄动距离函数最佳逼近元的存在性

应用Gateaux导数的性质来研究摄动距离函数最佳逼近元的存在性,得到了最佳逼近元存在的必要条件和充分条件.     

实域内Newton-Pade''''逼近与最佳有理逼近之间的关系

在[1]中,J.L.Walsh研究了Tchebycheff意义下最佳有理逼近与经典pade′逼近之问的关系。本文把[1]中的结果推广到Newton-Pade′逼近和Pade′型逼近。     

关于Orlicz空间中多项式最佳逼近元的特征

最佳逼近理论在工程中应用,需要解决最佳逼近元的实现问题。该文在Orlicz空间中研究最佳多项式逼近元的特征,得出了Otlicz空间中最佳多项式逼近元的充分必要条件和判别法,为Orlicz空间中最佳逼近元的实现找到了一种方法。     

作为最佳有理逼近极限的Newton-padé逼近和padé型逼近

在[1]中,J.L.Walsh研究了Tchebycheff意义下最佳有理逼近与经典pade逼近之间的关系,他得出了当区域充分小时,在此区域上对给定函数的最佳有理逼近是以该函数的padé逼近为极限,本文把[1]中的结果拓广到Newton-padé逼近与pade型逼近上去,     

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