二硫化铁光电薄膜制备技术的研究进展

黄铁矿结构的二硫化铁(FeS2)是一种具有合适的禁带宽度(Eg≈0.95 eV)和较高光吸收系数(当λ≤700 nm时,α=5×105cm-1)的半导体材料,而且其组成元素在地球上储量丰富、无毒,有很好的环境相容性。因此,FeS2薄膜在光电子以及太阳能电池材料等方面有潜在的应用前景,受到人们的广泛关注。本文从不同制备方法所制备出的二硫化铁薄膜的研究结果,来分析二硫化铁薄膜的研究状况。     

FeS2薄膜成分与Fe膜硫化温度的关系

采用真空热蒸发法在玻璃基片上沉积厚度约为500 nm的铁膜,然后对铁膜在温度为553~673 K的条件下恒温硫化6 h,以制备二硫化铁薄膜.通过对所制备的薄膜进行结构和成分分析发现,当硫化温度为603~653 K时,Fe膜硫化完全,所得薄膜为单一物相的FeS2薄膜,薄膜晶粒大小均匀,表面致密,S/Fe值为1.94~1.96,接近理想化学配比.     

硫化温度对两步法制备FeS2薄膜性能的影响

在553 K、573 K、603 K、653 K、673 K硫化温度下用两步法制备FeS2薄膜。分析了所制薄膜的结构及光电性能等,同时还研究了硫化温度对两步法制备FeS2薄膜的影响规律。     

光电薄膜材料FeS2(黄铁矿)的研制

研究了用电沉积法制作太阳能电池薄膜材料.分别用三种含铁元素和硫元素的水溶液淀积FeS2薄膜,将所得的样品在N2氛围中退火,退火温度分别为400℃和500℃.结果表明,从FeSO4*7H2O+Na2S2O3*5H2O水溶液得到的薄膜中含FeS2的衍射峰比从其它两种水溶液得到的薄膜中含FeS2的衍射峰多而明;退火温度为400℃比500℃更合适;另外,为防止薄膜氧化,在真空中干燥效果最佳.     

铁粉表面硫化处理制备高密度Fe-Cu-C合金

突破常规铁基粉末合金的制备工艺,设计出一种制备高密度Fe-Cu-C合金的新工艺.通过对铁粉表面进行硫化处理,Fe与S反应合成FeS,均匀包覆在Fe粉颗粒表面,形成一层FeS润滑薄膜,有利于降低压制摩擦力.通过X射线衍射、扫描电镜、和场发射扫描电镜分析研究材料的物相、元素分布和显微组织.研究结果表明:包覆在铁粉颗粒表面的FeS薄膜,有利于提高压坯密度,活化烧结.当S质量分数为0.5%时,硫化处理的Fe-2Cu-0.8C合金的力学性能优异,压坯密度7.31 g·cm-3,硬度78.6 HRB,抗拉强度485 MPa;当S质量分数达到0.8%时,多余的FeS占压制体积分数,导致试样的压坯密度降低,力学性能降低.     

黄铁矿材料合成条件的热力学分析

对主元素活度项法优势相图计算机绘制过程作了改进,利用QBasic软件和Origin制图系统计算和绘制了Fe-S-O体系的lgPS2-lgPO2优势区相图和lgPS2-lgPSO2优势区相图,并利用这些优势区相图分析了黄铁矿合成时残余氧气杂质对黄铁矿材料的影响,结果表明:(1)使用流动的高纯惰性气体携带硫化气体(如S2)与加热的Fe或其氧化物起硫化反应制备二硫化铁时,为了保证合成黄铁矿的纯度,合成反应发生前必须让残余氧与硫充分反应去除残余氧;(2)硫磺与Fe或其氧化物一起密封于石英容器中,在573~773 K加热处理从理论上可以制备高纯的FeS2。     

真空蒸镀法制备巨磁阻抗材料

采用真空蒸镀法在玻璃基片上制备具有巨磁阻抗效应的单层FeS iB薄膜.通过改变驱动电流方向和外磁场方向,得到4种测量巨磁阻抗效应的方式.通过比较发现,只有当外加磁场和单轴磁各向异性方向垂直时才有比较明显的巨磁阻抗效应的出现,并比较了磁各向同性和磁各向异性FeS iB薄膜的巨磁阻抗效应.验证了用真空蒸镀法能够制备具有巨磁阻抗效应材料的可行性.     

CuGa_(1-x)In_xSe_2薄膜材料的研究进展

CuGa_(1-x)In_xSe_2薄膜材料是具有黄铜矿结构的半导体化合物,由于具有大的吸收系数,并可通过改变x来调整禁带宽度从而实现能隙裁剪等优点,已广泛应用于制备太阳能电池,其转化效率可高达18.8%。目前,CuGa_(1-x)In_xSe_2薄膜的制备主要有三段制备法和金属层预置后硒化法两种。对上述两种制备方法进行了介绍,总结了CuGa_(1-x)In_xSe_2薄膜材料在太阳能电池中的商业化现状。并提出今后CuGa_(1-x)In_xSe_2薄膜材料研究应在进一步研究薄膜的形成机理,降低缺陷,寻找更合适的晶格适配率衬底材料等方面进行。     

硫化时间对FeS2薄膜结构和性能的影响

在硫化温度为653 K和硫化时间分别在3、6和12 h的条件下,用硫化铁膜法制备FeS2薄膜.通过对不同条件下制备的薄膜成分、结构和光电性能研究表明:当硫化时间大于6 h时,薄膜的成分接近理想化学配比,直接光学能带间隙大约为1.15~1.17 eV,电阻率约为1.3Ω.cm.     

高功率Li/FeS2电池的研制

随着信息技术的快速发展,用电器对电池的需求也日益增长,尤其是对高能量高功率电池的需求,而普通碱性电池显然无法满足这种要求.本文作者在国内率先成功研制了采用改性FeS2作为正极材料的AA型高能量高功率Li/FeS2电池.天然FeS2经过研磨、焙烧和酸洗,可最终制得改性FeS2.讨论了天然及改性FeS2的化学成分、物理性质和结构特征,并分别测试了二者组装成锂电池的放电容量.研究结果发现:FeS2的纯度、颗粒大小是影响Li/FeS2电池电化学性能的重要因素.在此基础上,对比了AA型Li/FeS2电池与同型号碱性电池的放电性能.Li/FeS2电池的整个制备过程完全满足环保的要求.研究表明:Li/FeS2电池是一种绿色、高功率的新型能源,具有广泛的应用前景.     

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)

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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).     

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.