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1.
运用C60分子的Ih对称性及矢量运算方法,引入调节参数λ计算了正二十面体被截取顶角后的具有C60分子结构的原子坐标.当输入的调节参数λ=0.337,C60分子的半径为Rc=3.55×10-10m时,计算得到长短键分别为1.449-6×10-10m和1.402-3×10-10m,与实验测量值相符.并计算了在C60面心立方晶体中,C60的二次轴与晶轴取向一致时的各原子坐标、键中心坐标和面心坐标.  相似文献   

2.
利用点电荷模型,计算了K3C60晶体的结合能,得出晶格常数为α=14.34A,并给出体积弹性模量,求得的晶格常数和实验测量值相符。  相似文献   

3.
用L-J势计算晶体中C60分子的旋转势垒刘奉岭王泽新姜云生(山东师范大学化学系,250014,济南;第一作者36岁,男,副教授)常温下C60以固体形式存在,其结构是面心立方即FCC结构.室温下,晶格质点上的C60分子已在作高速旋转.到目前为止,对晶...  相似文献   

4.
应用射频溅射技术制备了面心立方结构的Fe1-xNix/Cu(x=0.26-0.54)金属超晶格,MgO单晶衬底的采用以及在面心立方结构的Cu上实施外延等措施保证了在Ni质量分数低至0.26时Fe-Ni合金层仍保持了良好的面心立方的晶体结构,而且直到液氦温区这种面心立方结构仍是稳定的,磁性测量表明,当Fe-Ni合金层的Ni质量分数低至接近因瓦合金成分(x=0.35)时,其合磁矩呈下降趋势,即表现出偏  相似文献   

5.
我们应用单晶X射线衍射方法研究了Mo(tu)3Cl3的晶体结构。晶体的空间群为C34-R3;单胞参数力:a=8.78A,C=17.56A。晶体的密度用排量法测得为 1.83g/cm3,单胞内含有三个Mo(tu)3Cl3(密度计算值为1.83g/cm3)。结构的测定主要是通过Patterson投影和电子密度投影的计算来解决的。研究结构表明,在Mo(tu)3Cl3分子中,MO原子和三个Cl原子、三个硫脲的S原子直接配位,这六个原子按顺式排布在八面体的顶点上,因此分子具有三次轴的对称性,而整个晶体是由一层一层的分子所构成的。  相似文献   

6.
铋(Ⅲ)与对溴偶氮氯膦配合物的研究   总被引:1,自引:0,他引:1  
测定了铋与对溴偶氮氯膦显色反应的电子光变,λmax=735nm。研究了pH值,CPAPB用量和显色时间对配合物稳定性的影响。在最佳条件下确定了配合物的组成Bi:CPAPB=1:3,并用改善的яцииирскнй方法求出Δε4=3.22×10^4,β3=1.96×10^13,配合物平均摩尔吸光系数的实验值Δε实验与计算值Δε计算比较,基本一致。  相似文献   

7.
3-甲基-4-硝基吡啶-1-氧(POM)与3,5-二硝基苯甲酸(3,5-DNBA)的复合型晶体从乙醇与丙酮的混合溶液中培养获得,其组成为1:1,己被元素分析和x射线衍射实验所证实;其熔点由DSC热分析测得,为122.6℃。该晶体化合物属单斜晶系,空间群为P21/n,单胞参数为:a=0.9553(2)nm,b=0.5775(4)nm,c=2.7962(4)nm,β=99.03(1)°,v=1.524(1)nm3,z=4,Dc=1.60g/cm3,λ(Mokα)=0.071073nm,μ=1.29cm-1,F(000)=752,最终R=0.051,Rw=0.165[w=1/σ2(F)],其中1802个可观察衍射点参与结构计算,复合型分子中存在一个氢键。  相似文献   

8.
C60Br24粉末单晶的制备及X—射线衍射分析   总被引:1,自引:1,他引:0  
介绍了制备C60Br24粉末单晶的新方法.用气相法制备出C60单晶颗粒.X-射线衍射分析表明制得的颗粒是纯C60单晶.然后用液体溴浸润C60单晶颗粒.72h后形成C60Br24单晶颗粒.样品在65℃下退火18h,以除去未反应的溴和使C60Br24分子排列规整.退火后样品的X-射线衍射谱较复杂,因为样品中还有无序的溴分子存在.于是将样品在相同退火温度下再退火36h.元素分析和红外光谱分析均表明经54h退火后的样品成分是C60Br24,它的X-射线衍射谱显然要清晰得多.对该衍射谱的最佳拟合得出C60Br24单晶为正交面心结构,其晶格常数为a=2.156nm,b=1.675nm,c=1.294nm.  相似文献   

9.
对Pr3+:YAG(钇铝石榴石)的晶场谱按D2对称,用中间耦合,算符等价方法进行理论计算,确定了其晶场参数为(cm-1):B20=-80,B22=-68,B40=-305,B42=390,B44=-1200,B60=60,B62=-186,B64=1082,B66=-170.计算的晶场能级与实验吻合.  相似文献   

10.
运用休克尔分子轨道(HMO)理论对紫红质中的色基-视黄醛骨架异构化现象进行了讨论挖计算结果表明:紫红质中视黄醛骨架共轭体系π→π*跃迁的最大吸收峰λmax=563nm,这与紫红质的λmax=498nm相近,但列接近受压紫红质的实验结果λmax=534nm;且视黄醛骨架结构共轭体系中C11-C12之间激发态的π键级为1.5860。明显小于基态π键级1.7469值,故当紫红质吸收光能进入激发态之后,1  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.
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.
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.  相似文献   

15.
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   

16.
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   

17.
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   

18.
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.  相似文献   

19.
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.  相似文献   

20.
The non-orthogonal localized molecular orbital(NOLMO)is the most localized representation of electronic degrees of freedom.As such,NOLMOs are thus potentially the most efficient for linear scaling calculations of electronic structures for large systems.However,direct ab initio calculations with NOLMO have not been fully implemented and widely used,partly because of the slow convergence issue in the optimization of NOLMO.We devel-  相似文献   

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