(Si, Er)双注入单晶硅近红外光发射

利用金属蒸气真空弧离子源，将硅和铒离子先后注入到单晶硅中，经快速退火制备出（Si,Er）双注入单晶硅发光薄膜，RBS分析表明铒原子分接受10％，即原子浓度约10^21cm^-3，XRD分析发现，随着Er注量增加，退火态样品中ErSi2相增多，显微结构分析表明，注量条件影响辐照损伤程度、物相变化和表面显微形貌，而这些结构变化将直接决定（Si,Er）双注入单晶硅发光薄膜近红外区光致发光。     

掺铒硅基玻璃的制备及光谱性质

通过溶液－凝胶技术制备了掺铒（Er)的硅基玻璃,测定了硅基玻璃中Er^3 的电子吸收光谱、红光外谱和光致发光光谱（PL谱）。结果显示,在室温下,Er在硅玻璃中产生波长1．54μm的红光荧光,其强度随掺杂浓度的不同而改变,0．5w%掺杂浓度下出现最大值。电子吸收显示Er^3 的特征吸收谱线,根据电子吸收光谱确定了Er^3 在硅基玻璃中的部分能级。     

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     

Ni增强Er在富硅氮化硅薄膜中的光致发光

采用反应磁控溅射技术沉积了掺Er的富硅氮化硅(SRN:Er)薄膜和SRN:Er/Ni3个周期的超晶格,两种薄膜都在1100℃进行退火实验。SRN:Er薄膜的光致发光谱为一个峰位在665～750nm的发光带和一个峰位在1.54μm的发光带,前者来源于SRN薄膜中的纳米硅,后者为Er3+的特征发射。SRN:Er/Ni超晶格的光致发光谱上出现Er3+在520,550和850nm附近的精细结构,并且Er3+在1.54μm的发光有12倍的增强。光谱精细结构的出现证明Er3+的微观环境由于掺Ni而变得有序。与在SRN中相比,在这种有序环境中Er3+的光学活性有明显的增强。拉曼散射光谱测量证明在SRN:Er/Ni超晶格中纳米硅的数目比在SRN:Er薄膜中有一定的增加。因而,Er3+1.54μm发光12倍的增强是Er3+本身光学活性的增强和纳米硅数目的增加共同作用的结果。     

钕离子注入单晶硅合成硅化物的研究

用ＭＥＶＶＡ离子源将Ｎｄ离子注入到单晶硅中形成钕硅掺杂层,用ＸＲＤ分析了掺杂层的物相,用ＡＥＳ分析了掺杂层中离子的浓度分布,分析表明,在强流钕离子注入后,掺杂层中有硅化物形成,且形成相的种类随注量,束流密度及后续热处理条件的改变而变化,还对钕硅化物的形成过程进行了初步讨论。     

缓冲气体对激光烧蚀制备掺 Er 纳米 Si 晶薄膜结构特性的影响

采用 XeCl 脉冲准分子激光器,保持激光脉冲比为1:3,分时烧蚀Er靶和高阻抗单晶Si靶,在10 Pa的Ne气环境下沉积了掺Er非晶Si薄膜. 在氮气保护下,分别在1 000℃,1 050 ℃和1 100℃温度下进行30 min热退火处理. 对所得样品的Raman谱测量证实,随着退火温度的升高,薄膜的晶化程度提高;利用扫描电子显微镜观测了所制备的掺Er纳米Si晶薄膜的表面形貌,并与相同实验参数、真空环境下烧蚀并经热退火的结果进行了比较. 结果表明,Ne气的引入,使形成轮廓明显的掺Er纳米Si晶粒的退火温度降低,有利于尺寸均匀的晶粒的形成.     

二氧化硅薄膜导热系数试验研究

根据3ω方法测试原理，搭建了薄膜导热系数测试平台．在40—170K温度范围内，测试等离子体增强化学气相淀积(PECVD)方法制备的SiO2薄膜导热系数，同时测试了掺杂体态硅基底的导热系数．测试结果表明：在这个温度范围内，SiO2薄膜的导热系数随着温度升高而增大；杂质对体态硅的导热系数存在很大的影响．基于Callaway模型对体态硅导热系数测试结果进行拟合得到的掺杂浓度与实际值吻合较好，表明3ω方法测试原理不仅可以用来测试纳米薄膜的热传导系数．还可用来测定体态硅基底的掺杂浓度．     

基于磁控溅射技术沉积光伏电池用硅基薄膜材料的研究

硅基薄膜太阳能电池是光伏电池领域最具有发展前景的组件.采用非平衡磁控溅射技术制备氢化硅薄膜和SiNx/Si纳米多层膜,并对其结构与性能进行了分析.结果表明,Si∶ H薄膜呈现出非晶硅和硅纳米晶颗粒复合结构;随着溅射混合气中氢气含量的增加,Si∶ H薄膜的晶化程度增强;Si∶ H薄膜的光学带隙均高于2.0eV.利用交替磁控溅射方法沉积的SiNx/Si纳米多层膜结构,其呈现出非晶相.     

ZrSiN纳米复合膜的显微结构、力学性能和强化机理

利用磁控溅射方法,采用不同成分的ZrSi复合靶,在单晶硅基底片上沉积不同Si含量的ZrSiN纳米复合膜.利用X射线衍射仪（XRD）、扫描电子显微镜（SEM）、高分辨透射电子显微镜（HRTEM）和纳米压痕仪等表征测试方法研究了Si含量对ZrSiN纳米复合膜微观结构和力学性能的影响.结果表明：随着ZrSiN薄膜中Si含量的增加,薄膜结晶程度先升高后降低,同时薄膜硬度和弹性模量先上升后下降;当Si与Zr的原子比为1∶24时,ZrSiN薄膜的硬度和弹性模量达到最大值31.6 GPa和320.6 GPa,此时ZrSiN薄膜内部形成Si₃N₄界面相包裹ZrN纳米晶粒的纳米复合结构;Si₃N₄界面相呈结晶态协调邻近ZrN纳米晶粒间的位向差,并与ZrN纳米晶粒之间形成共格外延生长,表明ZrSiN纳米复合膜的强化来源于ZrN纳米晶粒和Si₃N₄界面相之间形成共格外延生长界面.     

衬底温度对掺杂硅基薄膜结构的影响

采用双离子束溅射沉积法制备的掺杂硅基Si-SiO2和Al-Si-SiO2薄膜,实验中通过改变基片温度获得不同条件下的样品.测试发现,当基片温度低于450℃时,两种薄膜的XRD谱图中并未有明显的晶态峰存在,说明薄膜中并未形成晶态结构,样品的选区电子衍射花样的TEM测试结果也证明如此;当基片温度高于450℃时,XRD谱图中才呈现出几个微弱的晶态峰,说明薄膜中可能有Si或A1的晶粒出现.样品的XPS测试结果表明,Si-SiO2薄膜在温度较低时表现为欠氧富硅的结构SiOx(x ＜2),薄膜中的Si主要是以氧化物的形式存在,当基片温度高于450℃时,根据Si的XPS特征峰的硅双峰结构能够确定薄膜中的硅形成了较显著的硅的原子团簇.而对于Al-Si-SiO2薄膜,Al主要是以单质铝的形式存在,Si是以氧化物的形式存在,实验中可以通过改变靶材中铝片的面积大小,改变薄膜中的铝和硅的含量.     

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.     

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…     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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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。     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

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