以尿素为沉淀剂制备纳米氧化锆的研究

以ZrOCl2·8H2O和CO(NH2)2为原料,利用微波诱导均匀沉淀法制得了纳米ZrO2,考察了反应物原始浓度、反应时间、不同反应物配比、煅烧温度和时间对产物粒径和形貌的影响,获得了均匀沉淀法制备氧化锆的最佳工艺条件,并对产品进行了表征.     

固相法制备氧化铁纳米粒子

采用固相法制备了氧化铁的纳米粒子，并对其进行了XRD谱图表征，发现产物氧化铁的晶型与灼烧温度及灼烧时间有关，随着灼烧温度的升高和灼烧时间的延长，氧化铁的晶型从γ型向α型转变。同时讨论了温度、时间等条件对产品粒径、产率等因素的影响。     

纳米金红石型二氧化钛粉末的研制

以硫酸法制备钛白粉工艺的中间产物--钛液为原料,采用均匀沉淀法,外加自制晶种为金红石化促进剂,以十二烷基磺酸钠为表面活性剂,尿素为沉淀剂,制备纳米金红石型二氧化钛粒子;研究了反应物浓度、反应物配比、反应温度、反应时间等对粒子粒径及产物收率的影响;利用TEM,XRD,BET,ICP-AES等分析测试技术,对粉体粒子的形貌、粒径、晶型、比表面积和纯度进行表征.研究结果表明所得二氧化钛粒子为金红石型,形貌呈球形,平均粒径达80 nm,产品纯度达99.95%;该制备技术工艺新,生产成本低,工艺操作简单,易于实现工业化,便于用硫酸法生产钛白的厂家在原有工艺基础上对中间产品进行深加工.     

纳米二氧化锰的制备及其形貌调控

采用水溶液化学沉积法制备纳米二氧化锰,用于空气电极的氧还原电催化剂,利用SEM、XRD、XPS等手段表征其晶态及组成,以考察反应温度、合成时间等反应条件对样品晶型和微观形貌的影响规律。结果表明:可通过控制反应条件调控纳米二氧化锰的晶型和微观形貌,获得的样品粒径范围为5~500 nm,其晶型和形貌分别为α-MnO2纳米线、δ-MnO2花球和γ-MnO2纳米粒子。通过实验现象,总结了纳米二氧化锰晶型与微观形貌的演变趋势,分析了晶型变化的机理。     

纳米TiO2的制备、表征及其表面光电性能研究

采用均匀沉淀和直接沉淀2种方法合成了纳米TiO2，对所得产物进行了透射电镜和粒度分布的测试．结果表明：均匀沉淀法制备的纳米TiO2粒度分布均匀，团聚少，并且粒径较小，大约在20nm左右，基本呈球形；直接沉淀法制备的纳米TiO2粒度分布不够均匀，团聚现象比较严重，有较大颗粒存在，粒径在40nm左右，近似呈球形．对均匀沉淀法制得的TiO2前驱物采用不同的灼烧温度和灼烧时间，得到了不同晶型和粒径的TiO2粉体．对相同灼烧温度、不同灼烧时间的TiO2进行了XRD测试．并从均匀沉淀法制备的不同粒径的金红石型纳米TiO2中选取3种不同粒径的样品，进行了表面光电压测试和分析．     

多孔氧化铁纳米花的合成与表征

在无模板剂和无表面活性剂的条件下,以K3Fe(CN)6和NaOH为原料,用水热法在180℃下反应2 h制备了具有混合形貌的铁的化合物.通过简易的形貌选择过程得到花状氧化铁的前驱体.将所得的前驱体在700℃下煅烧4 h后制备出多孔花状纳米氧化铁.用XRD、SEM、HRTEM等对合成的产物进行表征,对多孔花状纳米氧化铁的形成机理进行了探讨.实验结果表明,多孔花状氧化铁是由厚度大约为20 nm的多孔纳米花瓣组成,花的直径约为8μm.     

纳米ZnO粉体的制备及其影响因素

采用均匀沉淀法，以六水合硝酸锌为原料，尿素为沉淀剂，在不同反应条件下，合成不同晶粒尺寸的纳米氧化锌，用XRD、TEM和BET等方法表征所合成产品的形貌和平衡晶粒度等，讨论不同反应条件对产物性能的影响，并确定最佳反应条件。实验表明，在Zn^2 浓度为0．2mol／L、与尿素的量比为1：4时投料，于124℃搅拌下反尖3．5h，经离心洗涤和超声波处理，粗产物于80℃烘干后，在200℃煅烧3h，所得产物平均粒径为32．8nm，且粒径分布窄、分散性好，产率在85％以上。     

均匀α-氧化铁纳米粒子的制备及表征

纳米粒子的制备已成为当今的研究热点，而α－氧化铁纳米粒子由于其独特的性能与广泛的应用，引起了多方面的关注。分别采用均匀沉淀法和强迫水解法来制备氧化铁纳米粒子，用XRD谱图和TEM电镜进行表征，并探讨了这两种制备方法及反应温度、反应时间等对产率及晶体粒度的影响。     

绒球状单分散氧化铁微纳米球的水热合成

采用水热法成功合成了绒球状单分散氧化铁微纳米球.对合成温度以及表面活性剂对产物物相纯度及形貌的影响进行了研究,同时对其形成机理进行了讨论.结果表明,该绒球状氧化铁微纳米球是由赤铁矿α-Fe2O3和四方纤铁矿β-FeOOH组成的,且以β-FeOOH为主产物.     

离子交换均匀沉淀法合成纳米CeO 2研究

以Ce(NO3)3.6H2O、Na2CO3为原料,采用新型弱酸性阳离子交换树脂均匀沉淀法制备CeO2前驱体,经500℃焙烧1～4h后获得了高纯度的纳米CeO2晶体.用热重分析、X射线衍射、扫描和透射电子显微镜等对前驱体和样品的形貌和粒径分布进行了表征,并对涉及的均匀沉淀机理进行了探讨.结果表明,制备的CeO2纳米晶体属立方晶系,样品分散性好,平均粒径为30～50nm.离子交换树脂均匀沉淀法具有操作简单易行,成本低,同时避免使用有机溶剂和表面活性剂,污染小,后处理容易,离子交换树脂可再生重复使用等优点.     

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).     

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.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.