杂化轨道的成键能力与键能

从杂化轨道的成键能力出发,讨论了成键能力与键强度关系,得出了影响键能大小的因素 .     

Schomaker—Stevenson公式中系数C的物理意义

作者认为,在共价键中,成键的两原子间也存在着相互极化,并分析了Schoma ker-Stevenson公式中系数c的大小与成键两原子间相互极化的程度具有相关性.     

分子轨道成键特性的判据

根据Ｍｕｌｌｉｋｅｎ布居，前文提出了成键度的概念，本文证明，成建度可以用于判断分子轨道的成键性质，本文将此判据称为成键度判据，并讨论了它与其它判据的关系，本文引入化学单元及其特性ＭＯ的概念，讨论了成键度判据在预测分子的化学性质和原子簇化合物成键规律方面的应用。     

团簇Co3MoS成键及热力学稳定性分析

[目的]研究微观状态下团簇Co3MoS稳定性的影响因素.[方法]在二、四重态下应用密度泛函理论对团簇Co3MoS进行优化分析,一共得到8种稳定构型.[结果]通过对校正能和吉布斯自由能等能量参数进行分析得出:团簇Co3MoS热力学稳定性最优构型为单帽三角锥型的构型1(4),该构型相比其他构型更易形成.通过对键长和键级采用多种处理方法综合分析得出:金属与非金属原子间的成键强度对团簇稳定性的影响大于金属与金属原子间成键强度对稳定性的影响,其中Mo-S键对团簇Co3MoS总成键键级贡献率是最大的,同时两个金属原子间的成键依然对团簇Co3MoS的稳定性起到了一定的促进作用.[结论]得出了金属与非金属原子间的成键对团簇Co3MoS热力学稳定性影响较大.     

Co-Fe-B非晶态合金成键及电子性质的DFT研究

利用密度泛函理论(DFT),通过团簇Co2FeB2,CoFe2B2的优化和计算,研究Co-Fe-B非晶态合金成键及电子性质.结果表明:团簇Co2FeB2(富Co)中主要的电子流向为B→Co,B→Fe,而团簇CoFe2B2(富Fe)电子流向多样化,这导致富Co合金中键级比例分布不均匀,而富Fe合金中键级比例相对均匀;另外,金属与B原子成键对合金稳定性的贡献最大,而两种团簇的M(max)-B与Co-Fe键协同作用相反:富Co团簇中Co-B与Co-Fe成键强度同增同长,而富Fe团簇中Fe-B与Co-Fe成键强度相互抑制.以上结论在一定程度上解释了富Co合金热稳定性差的现象.另外,B原子使富Fe团簇空间结构、成键以及电子流动方向更加复杂,使合金非晶态化增加.Co-Fe-B非晶态合金中存在B原子之间近距离接触,希望此结论不久后得到实验验证.     

分子轨道成键能的计算［Ⅰ］──部分小分子分子轨道成键能的计算结果

计算了ＣＯ、ＣＯ２、ＣＯ、ＮＯ、ＮＯ２、ＮＯ等分子轨道成键能，分析了成键性质，解释了双原子分子的ＰＥＳ谱．     

GaN（0001）表面吸附TiO2的DFT研究

建立了GaN(0001)2×2表面吸附模型,采用基于DFT动力学赝势方法,对TiO2分子的吸附进行了理论计算.研究了TiO2分子在GaN(0001)表面的吸附成键过程、成键方位及表面化学键特性.计算结果表明吸附过程经历了物理吸附、化学吸附与稳定态形成的过程,化学结合能达到7.184～7.423 eV.不同初始位置的TiO2分子吸附后,Ti在fcc或hcp位置,两个O原子分别与表面两个Ga原子成键,Ga—O化学键表现出共价键特征,O—O连线与GaN[11-20]方向平行,与实验观测(100)[001]TiO2//(0001)[11-20]GaN一致.     

团簇Co3NiB2的成键分析与电子性质

采用密度泛函理论方法,对团簇Co_3NiB_2在B3LYP/Lan12dz水平下优化后得到的12种稳定构型的成键和电子性质两方面进行分析,得到以下结论:团簇Co_3NiB_2优化构型中各成键的成键强度由大到小为:金属与非金属之间成键金属之间成键非金属之间成键;各成键对团簇Co_3NiB_2稳定性贡献由大到小为:金属与非金属之间成键金属之间成键非金属之间成键;单帽四棱锥构型的电子主要是由Ni原子流向Co原子;单帽三角双锥与四棱双锥构型的电子均由B原子流向Co原子和Ni原子;在五棱锥构型中,电子由Co原子和Ni原子流向B原子。     

最大成键能原理及其应用

本文提出了最大成键能原理。由此出发，求出相应的最大成键能分子轨道及成键能，并得到了分子中各原子间的成键能，这些可以很好说明分子的成键和分子吸原子间键强度的性质，与实验事实吻合。同时，还可以得到分子的Ｍｕｌｌｉｋｅｎ＇ｓ布居数，与通常的ＬＣＡＯ－ＭＯ方法一致。     

P_7~ 原子团簇及其特殊配位

在激光产生的磷原子团簇正离子的质谱图中 ,P7 具有最强的谱峰 .使用分子图形软件设计出 2 4种 P7 的同分异构体 ,并进行分子力学、PM3半经验量子化学和 ADF密度泛函优化 .在磷原子团簇正离子模型中 ,磷原子采用二、三、四或六配位方式成键 .从各异构体成键能量的比较中可得知 ,最稳定的 P7 构型是在最稳定的 P6的双键位置增加 1个磷原子所生成的结构 .在磷原子六配位的结构中 ,d轨道参与成键 .具有平面或六配位原子的 P7 结构是不稳定的结构 .     

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.     

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.     

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.     

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.     

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.     

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

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