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…     

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 …     

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   

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。     

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。     

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。     

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

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.     

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.     

Design and analysis of generic LBS application developing platform

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.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

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.