g-C3N4/germanene异质结物理性质的密度泛函计算-电场的影响

通过第一性原理计算研究电场强度和方向对于g-C3N4/germanene双层的结合能、态密度以及电荷的影响.计算结果显示,电场对于双层的物理性质影响很大,方向朝上的电场使得态密度曲线向左移动,同时方向朝下的电场使得态密度曲线朝右移动.并且在电场的影响下,功函数的变化不大.     

强外场中的TiO分子结构及特性

利用多种方法在不同基组水平下,对TiO基态分子的几何构型进行优化.通过对比选用密度泛函(DFT)B3LYP/6-311+G方法研究在强外电场(-0.02 a.u.~+0.02 a.u.)作用下的TiO分子的基态键长、总能量、HOMO能级、LUMO能级、能隙及势能曲线的变化规律.结果表明：在一定外加电场范围内,随电场强度的增大,分子键长变小;总能量升高;HOMO能级、LUMO能级均依赖外加电场方向,随电场的增大而降低;能隙不依赖于电场方向,随电场强度的增大而减小;势能曲线在外电场中有“平移”效应,其中反向电     

g-C_3N_4/germanene异质结物理性质的密度泛函计算-电场的影响（英文）

通过第一性原理计算研究电场强度和方向对于g-C3N4/germanene双层的结合能、态密度以及电荷的影响.计算结果显示,电场对于双层的物理性质影响很大,方向朝上的电场使得态密度曲线向左移动,同时方向朝下的电场使得态密度曲线朝右移动.并且在电场的影响下,功函数的变化不大.     

铝金属薄膜上制备OTS自组装分子膜的摩擦学特性

为研究铝金属薄膜上三氯十八硅烷(OTS)自组装分子膜的摩擦学特性,采用自组装的方法在铝金属薄膜上制备OTS自组装分子膜,分析了纳米尺度和毫牛尺度下载荷、滑动速度以及紫外照射对薄膜摩擦学特性的影响.结果表明:制备的OTS自组装分子膜具有疏水特性和良好的润滑性能.紫外照射5 min后,自组装分子膜摩擦力降低;紫外照射15 min时,自组装分子膜的网状结构受到破坏,减弱了润滑效果.在纳米尺度和毫牛尺度下,摩擦力随载荷和滑动速度的增大而增大;铝金属薄膜摩擦系数降低时,自组装分子膜磨损显著降低,摩擦副的耐久性略有提高.     

Ni膜与Ti基体之间的界面结合能研究

报道了用断裂力学的三点弯曲实验测试Ni膜与Ti基体之间的膜基界面结合能G,并与剥离实验结果以及Miedema模型计算结果进行了对比.结果表明:断裂力学方法测得的界面结合能G随基体的表面粗糙度R a 值的增大而增大,而与薄膜厚度无关;断裂力学方法测得的本征界面结合能与Miedema模型计算结果一致,而与剥离实验结果有差距,但仍具有可比性.文中还讨论了用断裂力学三点弯曲实验方法测量膜基界面结合能的适用范围.     

外电场作用下α-丙氨酸手性分子的结构和电子光谱

采用密度泛函B3LYP及含时密度泛函理论(TD-DFT),在6-31+G(d,p)基组水平上,得到了不同外电场(-0.015~0.005)作用下的α-丙氨酸分子基态电偶极矩和分子总能量,并研究外电场作用对α-丙氨酸分子的激发能ΔE及振子强度f的影响规律.结果表明:分子偶极矩随电场强度的增加先减小后急剧增大;当电场强度为0时,分子总能量为-323.773 9,随着电场强度的增加,分子总能量升高,当F=0.005时达到最大值-323.771 5;激发能ΔE随电场强度的增加呈减小趋势,即电场作用下的α-丙氨酸分子易形成激发态.     

对称外场作用下椅型环戊酮分子的结构和性质

采用密度泛函理论(DFT)中的B3P86/6-311++G(d,p)方法,计算得到环戊酮(椅型)分子沿x轴方向在不同对称电场(-0.006~0.006)作用时的基态几何结构、电偶极矩和分子总能量.计算结果表明:电场强度大小影响分子的几何构型;分子偶极矩随电场强度的增加而增大;当电场强度F=0时,分子总能量为-271.481 6,分子总能量随电场强度的增加而降低;当F=-0.006时达到最大值-271.475 2,系统总能量随电场强度的增加而逐渐降低.     

自组装单层膜的研究

自组装膜(self-assembled monolayers,SAMs)是通过有机分子反应活性头基与固体界面之间自发反应形成的稳定、有序、紧密堆积的超薄膜结构.近年来,通过界面自组装在固体表面形成超薄层有机材料的研究受到人们的广泛关注,在非线形化学、分子生物学、材料科学、分子器件、生物传感器等领域具有广泛的应用前景.对自组装单层膜的制备、特点、类型、机理和应用等方面进行了探讨.     

含咪唑烷基硫醇自组装膜界面铜离子配位研究

合成了6-(咪唑-2-基)-1-己硫醇(IHT),在金电极表面形成纯的自组装膜及其与1-己硫醇(HT)的混合自组装膜,并将这些自组装膜在溶液中与铜离子进行界面配位.应用电化学循环伏安法和交流阻抗谱法探讨了各种自组装膜修饰电极界面配位铜离子的电化学行为.实验结果表明,IHT与HT以1∶4比例进行界面组装得到的混合自组装单分子层最致密,自组装膜的铜离子界面配位浓度最高达到2.3×10-11mol/cm2.界面形成的IHT-Cu2+配合物在不同的pH值溶液中测量结果表明该配合物在pH 6.4时是可以稳定存在的.     

环辛酮分子在非对称外电场作用下的光谱性质计算

采用密度泛函理论中的B3P86方法, 在6-311++G(2-df-)基组水平上, 计算得到不同外电场(-0.008 0~0.002 5)作用下环辛酮分子的基态构型, 再用含时密度泛函理论(TD-DFT)方法研究相同电场强度对优化环辛酮分子激发能和振子强度的影响. 计算结果表明： 电场强度影响分子的几何构型; 激发能随电场强度反向变化, 即环辛酮分子在电场作用下易解离和激发.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

正~~     

An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

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.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.