Sz（a）sz-Durrmeyer算子的点态逆结果

用一个单调函数ω(t) 为中介,利用Szasz-Durrmeyer算子导数的性质以及该算子的可换性和光滑模ωφλ(f,t)为特点,得到以下点态逼近逆定理对于f∈C[0,+∞),0≤λ≤1,φ(x)=x,δn(x)=φ(x)+1/n, 若|f(x)-Sn(f,x)|≤Mω(n-1/2δ1-λn(x)),其中ω(t)≥0, ω(ut)≤C(u2+1)ω(t),则对任意t>0,有ω2φλ(f,t)≤Ct2∑0＜n≤t-1(n+1)ω(n-1)+Ct2‖f‖,ω1(f,t)≤Ct∑0＜n≤t-1ω(n-(2-λ)/(2))+Ct‖f‖.此结果推广了有关ωφ(f,t)和ω(f,t)的结果.     

БЕРНШТЕИН第一求和算子的逼近阶的估计

对于БЕРНшТЕИН[1]提出的逼近连续周期函数的求和算子Un(f;x)=1/(2n+1) sum from k=0 to 2n f(x_k)〔sin2/2(x-x_k)/sin(x-x_k)/2 〕~2,HATAHCOH[2]证明了它的收敛性.至于误差估计,本文得到:1)若f∈C2π,则|Un(f;x)-f(x)|≤(5+3/2π)ω(f,lnn/n)(n≥3),2)若f∈C2π且f∈Lipiα(0<π<1),则|Un(f;x)-f(x)|≤〔7/4+3/(1-α)〕(2π/2n+1)~α,3)若f∈C2π且f∈Lipil,|Un(f;x)-f(x)|≤15·ln(2n+1)/2n+1。     

关于二元连续周期函数用Vallèe—Poussin和逼近

设Q={(x,y) |-≤x,y<π},△=a~2/ax~2+a~2/ay~2是Laplace算符,函数类△~rH 1, _2(r=0,1,2,……)由C(Q)中有直到2r阶偏导数并满足下述条件的函数f(x,y)组成:记ψ(x,y)=△~r(f)=△(△~r(-1)(f)),(△~o(f)=f),则对任意的-π≤x,x′,y,y′<π,成立着:|ψ(x,y)—ψ(x′,y′)|≤ψ_1(|x—x′|)+ω_2(|y—y′|),其中ω_1(t),ω_2(s)是任意给定的连续模,又f(x,y)∈C(Q),S_i,i(f:x,y)为f的Fourier部分和,而f(x,y)的Vall e-Poussin和是指量σ_(nm)~(kp)(f:x,y)=1/k+1 1/p+l sum from j=0 to sum from i=0 to pSn-j,m-i(f:x,y)文中讨论了量当n.m→∞时的渐近状态,在一定的条件下得到了渐近等式。所得结果是[3]中r=0时结果的推广,同时,简化了[3]中的余项。     

微分方程的非负周期解

讨论了微分方程x(n+m)=a(n)x(n)+f(n,x(n)) ,0相似文献   

三维空间中一类非线性Schroedinger方程组孤立子的不稳定性

在三维空间中研究了一类非线性Schrödinger方程组的初值问题it+rΔ=a(p+1)||p-1|ψ|p+1, t＞0, x∈R3,iψt+sΔψ=b(p+1)|ψ|p-1||p+1, t＞0, x∈R3,(0,x)=0(x), ψ(0,x)=ψ0(x), x∈R3.利用变分法得出了带基态的孤立子的存在性,并证明了该孤立子的不稳定性.     

Bochner-Riesz平均带权的强性求和

设f∈L~p(R~n),1≤p≤2(n+1)/n+3,以及δ>n/p-(n+1)/2.本文证明了f在R~n上的Bochner-Riesz平均σR(f;x)满足关系式其中权函数w满足条件w(u)≥0以及1≤1/t integral from 0 to t(w(u)du≤C)(C为一绝对常数)。结论对周期情形也成立。     

正、余弦函数的分析定义与重要极限的证明

由函数①C(x)=1+sum from n=1 to ∞(-1)~n(x~(2n))/((2n)!)(n∈N,x∈R), ②S(x)=sum from n=1 to ∞(-1)~(n-1)(x~(2n-1)/((2n-1)!)(n∈N,x∈R),的奇偶性,C(0)=1,S(O)=0,C~2(x)+S~2(x)=1,周期性,点[C(x),S(x)]与单位圆上点一一对应推出C(x)=cosx,S(x)=sinx,即     

三维空间中一类非线性Schrodinger方程组孤立子的不稳定性

在三维空间中研究了一类非线性Schrodinger方程组的初值问题:it+rΔ=a(p+1)||p-1|ψ|p+1, t＞0, x∈R3,iψt+sΔψ=b(p+1)|ψ|p-1||p+1, t＞0, x∈R3,(0,x)=0(x), ψ(0,x)=ψ0(x), x∈R3.利用变分法得出了带基态的孤立子的存在性,并证明了该孤立子的不稳定性.     

二阶随机脉冲微分方程周期边值问题随机解的存在性

本文在一定条件下,研究了形如 x″=f(t,x,x′,ω),t∈(0,T),t≠t_k,ω∈Ω,k=1,…,p. x(t_k~+,ω)=I_k(x(t_k~-,ω),ω),ω∈Ω,k=1,…,p, x′(t_k~+,ω)=N_k(x′(t_k~-,ω),ω),ω∈Ω,k=1,…,p, x(0,ω)=x(T,ω),x′(0,ω)=x′(T,ω),ω∈Ω(T>0为某常数)的二阶随机脉冲微分方程周期边值问题,得到了解的存在定理.     

一类具有偏差变元的二阶泛函微分方程周期解

利用重合度理论,研究一类具有偏差变元的二阶微分方程x″+f(t,x′(t))+g(t,x(t-τ(t)))=p(t)的周期解的存在性问题.其中,f,g∈C(R×R,R),且对任意的x∈R,g(t+ω,x)=g(t,x),p∈C(R,R),τ∈C(R,R)是ω-周期的.在不要求对所有的y∈R,函数f(t,y)≤0(f(t,y)≥0),t∈R的情况下,得到该类方程至少存在一个ω-周期解的充分条件.     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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-