共用铍原子稠合杂硼烷结构规则的探讨

本文利用EHMO量子化学计算方法,对已知的共用Be原子稠合杂硼烷的分子进行了计算。结果表明,对共用Be原子稠合的主族杂硼烷,其价成键轨道数可以表示为 NVBO=4n-(F_1+F_2)+2其中n是稠合骨架中所含有的主族原子总数,F_1和F_2分别为与稠合的两个骨架单元的几何特性有关的数值。     

硼烷电子结构的量子化学计算(Ⅱ)——骨架B_n及B_nH_n~(2-)电子结构的CNDO计算

本文用CNDO/2方法计算了封闭、巢型和网型硼烷骨架B_n及封闭B_nH_n~(2-)(5≤n≤12)的电子结构。结果表明文献〔2〕建议的硼烷拓扑成键规则是正确的。同时,讨论了骨架B_n及B_nH_n~(2-)的稳定性。     

半氟烃链作桥链的对称酯类二聚体的合成及介晶性

合成全氟烃链或半氟烃链作为中心桥链的二聚体化合物可能出现新的性能,作为液晶材料具有较大的研究价值.合成了7个以半氟烃链作为桥链的对称酯类二聚体化合物H2n+1CnO-C6H4-COOCH2C6 F12CH2OOC-C6H4-OCnH2n+1(n=4,1a;6,1b;10,1c),H2n+1 CnO-C6H4-C6H4-COOCH2C6F12 CH2OOC-C6H4-C6H4-OCnH2n+1(n=4,2a;6,2b;12,2c)和C6F13CH2CH2COOCH2C6F12CH2OOCCH2CH2C6F13(3).差示扫描量热法(DSC)和偏光显微镜(POM)对其介晶性研究发现:化合物2a具有典型的焦锥扇形织构SA相,化合物2b出现塑晶相.分别比较结构相类似的化合物1a～1c,2a～2c的熔点,发现随着烷氧基链的增长,存在降低趋势.三段半氟烃链的对称酯类二聚体化合物3未观察到介晶性.     

[Ag_3(μ_3-Cl)_2(dppm)_3]ClO_4晶体的结构

[Ag_3(μ_3-Cl)_2(dppm)_3]ClO_4 晶体属单斜晶系。空间群 P2_1/n;a=1.155(9),b=2.752(4),c=2.296(4)nm;β=102.8(1)°;V=7.110 6 nm~3。分子骨架为一不对称的三角双锥体,三个Ag原子以Cl原子为桥连接起来。     

Numerical Value Results OF Guassian Beam Focussing

1　Lensisplacedinbeamwaist　　WeconsiderthecaseofaGaussianbeamthatisincidentatitswaistonathinlensoffocallengthf.Tofindthelocationofthewaistoftheoutputbeamandthebeamradiusatthatpoint,westartwiththeABCDlaw .Attheinputplane( 1 )ω =ω0 1 ,R1 =∝sothat1q1 =1R1 -i λπω20 1 n =-i λπω20 1 nUsingtherelationω2 =ω1and 1 /R2 =( 1 /R1 ) - ( 1 /f)leadsto 1q2 =1q1 - 1f =- 1f -i λπω20 1 nq2 = 1- 1f -i λπω20 1 n=-a+iba2 +b2 ,a=1f,b=λπω20 1 n,q3=q2 + 1 =-aa2 +b2 + 1 + iba2 +b2Atplane( 3)weo…     

指数和的渐近公式

设A(α ,x) = x≤ne axkq 满足 (a ,q) =1,n为一个正整数 .1≤d≤D 相似文献   

柯西(Cauchy)不等式的一种证明方法

柯西 ( Cauchy)不等式是指 :( a1b1+a2 b2 +… +anbn) 2 ≤ ( a12 +a2 2 +… +a2n) ( b12 +b22 +…+b2n) ( ai,bi∈ R,i =1 ,2 ,… ,n) ,当且仅当 a1b1=a2b2=… =anbn时等号成立。这个不等式的证明方法很多。现利用二次型理论来证明柯西 ( Cauchy)不等式。证明 :记 f ( x1,x2 ) =( a1x1+b1x2 ) 2 +( a2 x1+b2 x2 ) 2 +… +( anx1+bnx2 ) 2　　 =( a12 +a2 2 +… +a2n) x12 +2 ( a1b1+a2 b2 +… +anbn) x1x2 +( b12 +b2 2+… +b2n) x2 2　　 =X′AX　　其中 X =x1x2　　　 A =Σni=1a2i　　Σni=1aibiΣni=1aibi　　Σni=1bi2　　显然 f …     

点数为素数方幂的线传递点拟本原的有限线性空间

设F为一个有限线性空间,G≤Aut（F）为F的线传递且点拟本原的自同构群,若v=p^n,p为素数,则下列之一成立（a)S=PG(d-1,q),d≥3且(q^d-1)/(q-1)=p^n,PSL（d,q)≤G≤PFL(d,q)。（b)v=q^2 q 1是一个素数且G是一个q^2 q 1阶循环群或是一个阶为（q^2 q 1)（q 1)或（q^2 q 1)q的Frobenius群。(c)线性空间的点集合是p元域上的n维向量空间V(n,p)的所有向量组成的集合,N≤G≤AGL(n,p)且G0是GL（n,p)的一个不可约的子群,这里N表示平移子群。     

不饱和烃同系物凝聚型物理性质递变规律的数学描述

以H-(CH2)n-CH=CH2和H-(CH2)n-C≡CH型同系物结构重复单元数值连续变化为模型,获得了描述该同系物凝聚型物理性质递变规律的数学表达式:P=(a0+a1n+a2n2)/(1+b2n2),式中a0、a1、a2、b2均为常数,n为结构重复单元数值,P为同系物的凝聚型物理性质。通过非线性回归分析,得到回归方程,结果表明同系物的凝聚型物理性质与重复结构单元数值之间满足上述关系式,并显示优良的相关性。     

金属在硼簇化合物中的作用

金属硼原子簇化合物包括金属硼烷、金属碳硼烷及其衍生物,分子几何构型千变万化。一个或多个金属原子(主族或过渡元素)束缚在硼骨架或碳硼骨架上,在作硼或碳硼骨架的稳定剂,或作合成的试剂时,金属所起的作用是很重要的。     

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-