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1.
 对自然数n, m, i∈N,设Ki表示i个顶点的完全图,Kn表示Kn的补图,St(m) 表示m+1个顶点的星形树,Gr为有r条边的优美图,Pn为n个节点的路,P2∨Kn是P2与Kn联图。 给出了非连通图(P2∨Kn)(0,0,r1,0,…,0,rn)∪St(m)和(P2∨Kn)(r1+a,r2,0,…,0)∪Gr的定义,并论证了当n≥2时,这两类图都是优美图。  相似文献   

2.
近金属表面的Rydberg氢原子的动力学性质   总被引:2,自引:0,他引:2  
用相空间分析方法和闭合轨道理论研究了近金属表面氢Rydberg原子的动力学性质. 由氢Rydberg原子与金属表面相互作用的Hamilton量, 通过坐标变换发现, 电子运动的相空间可以分为振动区和转动区, 从Poincaré截面和闭合轨道都能很清楚地说明这一点. 选取主量子数n = 20的氢原子, 其动力学行为敏感地依赖于原子与金属表面间的距离 d: 在d较大时, 原子与金属表面间的相互作用表现为经典的van der Waals力, 系统是可积的; d变小时, 存在一个临界值dc. 当d>dc时, 系统是近可积的, 接近于规则运动; d<dc时, 系统是不可积的, 运动是混沌的, 轨道是不稳定的, 电子有可能被金属表面俘获.  相似文献   

3.
-F-残缺数据的辨识与恢复   总被引:16,自引:8,他引:8  
利用P-集合结构中的内P-集合与-F-元素删除集合,给出-F-残缺数据的概念,它是由(x)-F与(x)-构成的一个数据对((x)-F-,(x)-)。由F-残缺数据,给出-F-残缺数据的生成与-F-残缺度。利用这些结果,给出-F-残缺数据的关系定理,-F-残缺度定理,-F-残缺数据的辨识定理,-F-残缺数据的恢复定理,给出-F-残缺数据的应用。  相似文献   

4.
采用Thermo-Calc及JMatPro软件,对GH105合金在600~1 600℃的相图进行计算,并对C,Cr,Co,Mo,Zr,Ti,Al以及微量B对GH105合金主要析出相MC,M23C6,M3B2,μ,σγ''的影响进行探究。结果表明:C的增加提高了M23C6和MC相的析出量和M23C6相的析出温度,降低了σ相的析出量和析出温度,同时μ相的析出温度明显下降;Cr的增加显著提高了σ相的析出量和析出温度;Co的增加提高了μ相和σ相的析出量和析出温度,降低了M23C6相的析出量和析出温度;Mo的增加显著提高了μ相和σ相的析出量和析出温度;Zr的增加提高了σ相的析出量和析出温度,提高了MC相的析出量,降低了M23C6相的析出量和析出温度;B的增加显著提高了M3B2相的析出量;Al,Ti和m(Al):m(Ti)的增加,提高了γ''相的析出量,其中Al和m(Al):m(Ti)相的增加还提高了γ''相的析出温度。  相似文献   

5.
<齐物论>为庄子内篇中重要篇章,体现道家哲学的中心思想,历来认为是庄子自著.根据司马迁<史记>没有记载此篇作为提出问题的依据,再通过<齐物论>与<老子>、<慎子>等比较,其言论多有相类之处.从著作年代看,<淮南子>有关言论为<齐物论>作注,<齐物论>产生不迟于<淮南子>;从<齐物论>综合<老子>、<慎子>及公孙龙子诸说看,其著作年代不得早于战国晚期,可见<齐物论>非庄子自著.  相似文献   

6.
以松木为模板,使用模板法制备了不同铈锆含量的CexZr1-xO2复合氧化物的催化剂,用于餐饮废油与甲醇进行酯交换反应合成生物柴油.采用BET、SEM对CexZr1-xO2进行表征分析.研究不同制备方法、CeO2的负载量和煅烧温度对催化剂活性的影响,以及不同的酯交换反应条件对生物柴油产率的影响.制备的CexZr1-xO2具有松木的生物形态,并有助于催化剂形成多孔道结构.以CexZr1-xO2为催化剂,考察甲醇和餐饮废油的酯交换反应.结果表明:当x=0.5,煅烧温度为600℃时,甲醇与餐饮废油物质的量比为60:1,催化剂用量(基于餐饮废油的质量)的质量分数为5%,反应温度为190℃,反应时间为6 h的反应条件下,酯交换反应的甲酯收率达到91.1%.  相似文献   

7.
 进一步研究L-fuzzy闭包系统,运用一一对应的思想和范畴论的方法研究了确定L-fuzzy闭包系统的另一种方法.设X是集合,L是Hutton代数,首先介绍了L-fuzzy弱邻域算子和它们的L-fuzzy连续映射,然后设L-FCSS是L-fuzzy闭包系统空间和它们的L-fuzzy连续映射构成的范畴,L-FWNS是L-fuzzy弱邻域算子空间和它们的L-fuzzy连续映射构成的范畴,证明了L-FCSS和L-FWNS是同构的.  相似文献   

8.
 利用固相合成干冷空气淬火法,合成了一系列Y3+掺杂的LiV3-yYyO8 (y=0,0.01,0.03,0.05,0.1,0.2)正极材料.XRD结果表明,Y3+掺杂量不同对LiV3O8结构的影响不同.适量Y3+掺杂能保持LiV3O8的原有结构,增大其d100值,同时降低材料的结晶度.当Y3+掺杂过多时,样品中会产生YVO4杂相.充放电循环、循环伏安(CV)及交流阻抗(EIS)测试结果表明,Y3+掺杂虽然降低了材料的初始容量,但适量的Y3+掺杂能稳定材料的循环性能.电池存放实验表明Y3+掺杂还能提高电池的存放性能.在高电压下存放15d后,掺杂样的放电容量保持率为94.2%,高于未掺杂样的88.2 %.  相似文献   

9.
系统研究了室温下Tb0.3Dy0.7(Fe0.9T0.1)1.95 (T = Mn, Fe, Co, B, Al, Ga)合金中ⅢA族金属和过渡金属元素T替代Fe对晶体结构、磁致伸缩、内禀磁致伸缩、自旋重取向的影响. 结果发现, 不同金属T替代Fe, Tb0.3Dy0.7(Fe0.9T0.1)1.95合金具有相同的MgCu2型立方Laves相结构. ⅢA族金属B, Al, Ga替代使磁致伸缩λs下降幅度较大, 同时发现Al, Ga替代使磁致伸缩容易饱和, 表明Al, Ga替代可降低 Tb0.3Dy0.7(Fe1-xTx)1.95合金的磁晶各向异性, 而过渡金属Mn, Co替代Fe使Tb0.3Dy0.7(Fe1-xTx)1.95合金磁致伸缩λs 下降幅度较小; 不同替代金属元素, 对内禀磁致伸缩l111有不同的影响. Mössbauer 效应表明, Al, Ga 替代使 Tb0.3Dy0.7(Fe0.9T0.1)1.95合金的易磁化方向在{110}面逐渐偏离了立方晶体的主对称轴, 即自旋重取向, B, Mn, Co替代未使易磁化轴发生明显转动.  相似文献   

10.
采用一步水解法,通过控制不同水解时间制备系列Bi12O17Br2,对其晶相、氮吸脱附、光吸收及电化学特性进行鉴定与表征。将Bi12O17Br2用于可见光辐照下光催化固氮的结果表明,随制备时水解时间的延长,Bi12O17Br2对N2的化学吸附量增大,光催化固氮的活性增加,在不采用助剂、仅有N2和水的情况下,产NH+4的速率高达144 μmol/(L·g·h)。电化学测定结果显示,随制备时水解时间的延长,所得Bi12O17Br2的电化学阻抗降低、光电流响应增大。  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.
何延凌 《科技信息》2008,(4):258-258
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.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

14.
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.  相似文献   

15.
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   

16.
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   

17.
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.  相似文献   

18.
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   

19.
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   

20.
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   

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