首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 93 毫秒
1.
综述了稀土元素在光、电、磁方面的应用,并对其应用进展情况作了分析和研究,指出稀土元素及其化合物表现出了许多独特的光、电、磁学性质,使得它在工、农业生产,现代高科技研究及国防现代化建设中有着十分广泛的应用前景.近年来,国内外开展了广泛的研究开发工作,特别是在新型功能材料方面,并取得了一系列的重要成果.  相似文献   

2.
Banach空间X的许多几何性质在不动点理论中都具有重要的作用,1997年,Garcia Falset证明了当R(X)<2时,Banach空间X具有不动点性质.本文通过研究了Banach空间X的(L)性质与Opial性质,一致Opial性质,Non strictOpial性质及R(X)几何常数之间的关系,得出了(L)性质与一致Opial性质的等价条件,并得到自反且具有一致Opial性质的Banach空间X具有不动点性质.  相似文献   

3.
本文引入的次 性质是文[2] 性质的推广,并讨论了次 的等价刻划。证明了  次  可数亚紧、次亚紧 次 ,给出的例子表明上述箭头均不可逆  相似文献   

4.
引入的弱P性质是介干P性质与可数亚紧之间的复盖性质,并讨论了弱P性质的等价画,它的遗传性和映射对它的作用。  相似文献   

5.
本文引入的F性质是文(2)F性质的推广,并讨论了次F的等价刻划,证明了F-次F-可数亚紧,次亚紧-次F,给出的例子表明上述箭头均不可逆。  相似文献   

6.
本文提出一种Fuzzy集的数学模型.它是建立在性质树、性质空间.性质空间的乘积以及逻辑序的基础上的.  相似文献   

7.
引入了一种介于B-性质与P-性质之间、介于中紧与可数中紧之间的拓扑性质--中B性质,并对这种性质作了系统的研究,分别讨论了它的等价条件、遗传性质和映射保持性,还讨论了乘积空间的中-B性质,最后举例说明中B-性质严格介于B-P-性质之间,严格是于中紧与可数中紧之间。  相似文献   

8.
糖在甲酰胺中体积性质的研究*汤清虎卢雁白同春张喜英⒇卢锦梭(河南师范大学化学系,453002,新乡,*周口师专)萄萄糖、果糖和蔗糖是多糖及其它复杂生物大分子的组成单元,同时又直接参予生物体内的代谢作用,为生命运动提供能量,因而研究它们的热力学性质具有...  相似文献   

9.
本文在局部凸空间中定义了H性质和Schur性质,考虑了这两种性质在积空间和商空间的遗传。同时,也得到了具无条件基的Banach空间具H性质或Schur性质的充要条件。  相似文献   

10.
以4-溴吡啶盐酸盐和对氨基苯甲酸为原料合成了4-(4-吡啶-4-基-苯甲酰氨基)-苯甲酸(HL). 通过溶剂热法合成得到配合物 [Zn2L2(CO3)(H2O)2]n (1). X-射线单晶衍射分析表明:配合物1结晶于单斜晶系P21/c空间群,结构中存在由Zn(II)离子与碳酸根氧原子形成的无机链,这些ZnO无机链进一步被配体L-中的羧基氧原子和吡啶氮原子连接,形成4-连接66拓扑的三维网络结构. 将配合物1直接作为锂离子电池负极材料,并对其电化学性能做初步研究.  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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号