退火对硅锗薄膜上低维结构的PL光谱的影响

采用激光辐照的方法在硅锗薄膜样品表面生成微米级小孔,用高精度扫描电镜观察孔内结构,发现片状的纳米结构. 用荧光光谱仪测其光致荧光谱,在705 nm处出现较强的光致荧光谱（PL）. 对片状结构在800 ℃下进行退火20 min后,其PL光谱明显蓝移至575 nm. 退火40 min后,在725 nm处有较宽的PL光谱,同时,在606 nm处有一尖锐的PL光谱. 利用量子受限和纳晶与氧化物的界面态综合模型解释PL光谱的产生.     

嵌入SiO2薄膜中的GeO和Ge纳米晶光致发光的研究

作者通过离子注入法得到了镶嵌于SiO2薄膜中的Ge纳米晶，并通过系统的氧化性或还原性退火处理，以改变样品中Ge的氧化物成分组成．分析了不同样品在室温下的光致发光(PL)特性，并结合XRD分析表明：300与400nm附近的荧光峰的发光机制是GeO(nc-GeO)纳米晶发光，而不是GeO的缺陷发光；570nm附近的荧光峰的发光机制为Ge纳米晶(nc-Ge)发光，而不是Ge及Si界面的缺陷发光．     

天然锗纳米晶的制备与中子嬗变掺杂研究

采用离子注入法及退火工艺,在硅基二氧化硅薄膜中制备了镶嵌结构的天然Ge纳米晶样品. 通过退火实验研究,发现随着退火温度的升高,纳米晶的晶态峰峰位红移,这意味着Ge纳米晶受到的应力减小. 当退火温度达到 700 ℃时,纳米晶的晶态峰强度显著增强,而且薄膜中与Ge有关的缺陷发光减弱. 采用中子嬗变掺杂法对天然Ge纳米晶进行了掺杂,X射线荧光光谱数据表明,样品中成功的引入了Ga杂质和As杂质. 薄膜中形成的与Ge有关的缺陷具有稳定的结构,中子辐照之后其发光仍然存在,而且,掺杂后的样品中没有发现与Ga或As有关的     

Ge/Al-SiO2薄膜材料的非线性光学特性

采用磁控共溅射及后退火技术制备Ge,Al共掺SiO2薄膜,通过X射线衍射谱和傅里叶红外吸收谱对样品进行表征,并采用皮秒脉冲激光器的单光束Z扫描技术研究薄膜的三阶非线性光学特性.研究结果表明:薄膜材料对1 064nm的光具有自散焦和双光子吸收效应,薄膜的三阶极化率χ(3)为3.84×10-16 m2.V-2.薄膜材料的三阶非线性极化率比SiO2和GeO2均有显著的提高,说明薄膜材料中的纳米Ge颗粒的量子限域效应及双光子吸收效应是其产生非线性光学效应增强的主要原因,同时Al的掺杂也促进了材料的三阶非线性光学效应的增强.     

含纳米硅氧化硅薄膜的光致发光特性

利用射频磁控溅射复合靶技术,通过调节复合靶的百分比制得富硅的氧化硅薄膜,并在不同的温度下退火,制得含纳米硅的氧化硅薄膜.通过Raman谱的测量,计算出800℃退火的薄膜中纳米硅晶粒的平均尺寸为5.6 nm,用X射线衍射测量同样的样品得出其粒径为6.0 nm.在室温下测量光致发光(PL)谱,探测样品的峰位为360 nm,并结合光致发光激发谱(PLE),研究相应的激发与发光中心.     

纳米Ge-SiO2薄膜对1342nm激光的被动调Q

采用射频磁控溅射技术和热退火处理方法制备纳米锗镶嵌二氧化硅( Ge-SiO2)薄膜.利用光吸收谱和X射线衍射谱对薄膜材料进行表征,得到薄膜的光学带隙为1.12 eV,纳米Ge晶粒的平均尺寸约为16.4 nm.将纳米Ge-SiO2薄膜作为可饱和吸收体插入激光二极管泵浦的平-凹腔Nd∶YVO4激光器内,实现1 342 nm...     

氢化钠米硅薄膜的光声光谱研究

分析了纳米硅薄膜材料从可见光到近红外范围的光声光谱，并与微晶硅和非晶硅材料进行了对比。纳米硅的光吸收系数比后两都高（特别是在１．４～１．９ｅＶ之间，高出近一个数量级），其原因是纳米硅薄膜中大量晶粒对光子的散射、晶粒界面缺陷的吸收及载流子吸收的影响，此外，纳米硅光声谱中Ｕｒｂａｃｈ边宽且缓，反映出这种材料很高的无序程度。     

溶胶凝胶法制备ZnO薄膜及性质研究

以二水醋酸锌为原料,使用溶胶凝胶法在(100)Si衬底上旋转涂敷得到ZnO薄膜.采用傅立叶变换红外光谱和X射线衍射(XRD)分析经N2、空气、O2不同气氛400℃退火ZnO薄膜的成分和结构差异.使用XRD、原子力显微镜和光致发光手段重点研究了N2气氛条件下,ZnO薄膜结构与发光特性随退火温度的变化规律,发现400℃下退火更适于干凝胶薄膜经历结构弛豫,生成具有(002)择优取向、性质优良的纳米晶ZnO薄膜.计算该样品的晶粒尺寸为41.6 nm,晶格常数a=0.325 3 nm,c=0.521 nm,其PL光谱出现495 nm附近强的绿光发射峰,可能源于ZnO纳米晶粒表面缺陷氧空位(Vo).随着退火温度升高,ZnO生成量减少、晶粒体表面积比(S/V)减小共同作用导致绿光峰强度变弱.     

溅射含纳米锗氧化硅复合薄膜的光致发光和拉曼特性

采用射频磁控溅射法制备了含纳米锗的氧化硅复合薄膜，在室温下对不同温度退火的样品测量了光致发光谱，其发光峰位均位于580nm，通过对样品所作的拉曼散射光谱的拟合，确定出了样品中纳米锗的尺寸，并发现纳米锗的平均尺寸随温度退火的升高在增大。     

氢化纳米硅薄膜的光声光谱研究

分析了纳米硅薄膜材料从可见光到近红外范围的光声光谱，并与微晶硅和非晶硅材料进行了对比．纳米硅的光吸收系数比后两者都高（特别是在１．４～１．９ｅＶ之间，高出近一个数量级），其原因是纳米硅薄膜中大量晶粒对光子的散射、晶粒界面缺陷的吸收及载流子吸收的影响，此外，纳米硅光声谱中Ｕｒｂａｃｈ边宽且缓，反映出这种材料很高的无序程度．     

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.     

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.     

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)

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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).     

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.