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1.
四阶边值问题的多个正解 总被引:3,自引:0,他引:3
马如云 《西北师范大学学报(自然科学版)》1997,33(2):1-5
在边值条件y(0)=y(1)=y″(0)=y″(1)=0或y(0)=y′(1)=y″(0)=y(1)=0下,研究方程d4ydx4-h(x)f(y(x))=0的多个正解的存在性,在假定f满足在无穷远处超线性而在零点次线性的条件下获得至少有两个正解的结果 相似文献
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本文研究了交替ω-有穷自动机关于接受条件Z1和Z2接受ω=语言的能力,并且与交替ω-有穷自动机关于另外接受条件接受ω-语言的能力进行了比较,从而得出了下面主要结果:AC1=AZ1=A62Z1=A^SZ2=AZ2。 相似文献
3.
张淑琴 《西北师范大学学报(自然科学版)》1999,35(3):22-28
通过构造适当的逼近序列获得了奇异方程u(4)(t)=f(t,u,u″)在边值条件u(0)=u″(0)=u(1)=u″(1)=0下正解的存在性 相似文献
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利用摆动进给竹材旋切机进行竹装饰单板最优化旋切试验,其结果分析表明:在本试验条件下最佳旋切参数是:装刀高度h=0;压尺压棱位置d=0;旋切后角α=3°~6°;软化条件为清水浸泡,竹段含水率W≥100%。 相似文献
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在文通过建立适当的比较函数,把Filippov「定理推广到更广义的方程x=h(y)-F(x),y=-g(x)上,讨论了极取环的存在条件。还有文运用了类似的方法,对更为广泛的方程x=Q(x,y),y=p(x)在Qy(x,y)≠0条件下进行探讨,得到了其存在的极限环的充分条件。 相似文献
7.
当k≥2,2kn+1=qh,q≡-1(mod2k),丢番图方程4/n=x-1十y-1+z-1有正整数解;当方程中n换以素数P,则P存疑的条件是Legendre符号有(P/3)=(P/5)=(P/7)=(P/11)=(P/13)=(P/17)=1. 相似文献
8.
讨论了二次系统(Ⅱ)δ=0具有二阶细焦点的条件,并对n=0时以原点O(0,0)为二阶细焦点的二次系统(Ⅱ)δ=0作了全局分析。 相似文献
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林丽平 《福州大学学报(自然科学版)》1999,27(4):1-1
考虑满足开集条件的线性迭代系统 Si (x) = aix + ci , i = 1 , …, m 产生的广义 Cantor 集在m = 2 时, 得到几个不等式, 并由此给出这类广义 Cantor 集的 Hausdorff 测度的精确值: Hs ( E)= | E|s 相似文献
11.
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. 相似文献
12.
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. 相似文献
13.
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。 相似文献
14.
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. 相似文献
15.
Miao Maosheng 《华南师范大学学报(自然科学版)》2014,(6)
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- 相似文献
16.
Yang Weitao 《华南师范大学学报(自然科学版)》2014,46(6):137-138
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- 相似文献
17.
Bernard Kirtman 《华南师范大学学报(自然科学版)》2014,(6)
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 相似文献
18.
Michael Springborg 《华南师范大学学报(自然科学版)》2014,(6):136
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 相似文献
19.
《上海师范大学学报(自然科学版)》2014,(5):550
<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 相似文献