溶胶凝胶法制备莫来石纤维及莫来石晶化的动力学研究

以异丙醇铝、硝酸铝和正硅酸乙脂为原料,通过溶胶凝胶法制备了可纺的莫来石前躯体溶胶,异丙醇铝和硝酸铝的最佳摩尔比为4:1.凝胶纤维在1 200℃煅烧1 h,得到了表面光滑、直径均匀的莫来石纤维.采用Kissinger方程和Ligero方程计算,得到莫来石晶化的活化能分别为993.5 kJ/mol和1 014.2 kJ/mol.     

SnO_2纳米粉体的制备研究

以Sn粒为原料,在柠檬酸体系中,用溶胶凝胶法合成了四方晶系的SnO2粉体.对前驱体进行了TG-DTA分析,用XRD、TEM对产物的组成、粒径大小、形貌进行了表征.结果表明:Sn∶柠檬酸的摩尔比为1∶2,煅烧温度在550℃时可生成粒度小、纯度高的SnO2纳米晶粉体.     

CuO//La2O3/γ-Al2O3合成2-甲基吡嗪的催化性能

用改进的柠檬酸络合法制备了CuO//La2O3/γ-Al2O3催化剂,并通过XRD、NH3-TPD技术对样品进行了表征,探索其对乙二胺(ED)和1,2-丙二醇(PG)为原料合成2-甲基吡嗪(2-MP)反应的催化活性。分别考察了催化剂不同金属配比、煅烧温度以及反应温度、气体空速等对催化剂活性的影响。结果表明:当铜铝摩尔比为4∶6,煅烧温度为700℃时催化剂的催化性能最好;在原料液中1,2-丙二醇、乙二胺和水的摩尔比为1∶1∶2、反应温度为320℃、气体空速(GHSV)1 815 h-1的条件下,1,2-丙二醇的转化率为100%,2-甲基吡嗪的收率为82.7%。     

乙二胺四乙酸配位螯合法制备钴铝尖晶石蓝色颜料

提出一种可以在较低温度下焙烧制备出钴铝尖晶石蓝色颜料的方法.以六水合硝酸钴、九水合硝酸铝为主要原料,乙二胺四乙酸(EDTA)为配位螯合剂,通过EDTA配位螯合钴、铝得到有机配合物前驱体,经过焙烧制备钴蓝颜料.通过国际照明委员会的色度图谱(CIE)、X射线衍射(XRD)和傅里叶红外光谱(FTIR),分别对所制备样品的物相和呈色进行研究表征.主要考察了钴铝物质的量比、反应体系pH值、焙烧温度等工艺条件对铝酸钴尖晶石相的完整性和颜料呈色的影响.制备钴铝尖晶石蓝色颜料的最佳工艺参数是900 ℃温度下保温时间为2 h,pH值为9~10,前驱体的钴铝比为 1∶2.5.     

硬脂酸凝胶法制备TiO2纳米粉末及其表征

以硬脂酸、钛酸四丁酯为原料,用硬脂酸凝胶法制备了TiO2超细粉末.运用差热-热重(DTA-TG)、傅里叶红外光谱对制备过程进行了表征;用X射线粉末衍射(XRD)、透射电镜(TEM)对纳米晶的粒径和形貌进行了表征.不同温度处理可得到不同晶型和形貌的纳米二氧化钛.     

溶胶-凝胶法制备Al2O3超细粉体

以硝酸铝为原料,柠檬酸为络合剂,采用溶胶-凝胶法制备Al2O3超细粉体,用X射线衍射仪、透射电子显微镜对粉体的晶体结构、粒径及形貌进行表征.考察了柠檬酸用量以及焙烧温度对A12O3粉体的物相、形貌特征的影响.结果表明:硝酸铝与柠檬酸的摩尔比为1:3,pH值为l时,可制备稳定的溶胶,溶胶经过120℃恒温干燥12 h后得到...     

纳米铝酸钴的合成与表征

采用硬脂酸凝胶法合成了纳米晶铝酸钴,通过TG-DTA,XRD和TEM对其进行了分析.研究结果表明:经煅烧处理得到的纳米晶铝酸钴粒径为17～33 nm、分布均匀、呈尖晶石结构;纳米晶的粒径随煅烧温度的升高而增大,其颜色随煅烧温度的变化而变化.该工艺比传统的方法煅烧温度降低了400～500 ℃.     

多孔陶瓷基锂离子吸附剂的制备及性能研究

采用溶胶-凝胶法在不同条件下制备Li_4Ti_5O_(12),通过XRD分析寻找出制备Li_4Ti_5O_(12)的理想条件.将高岭土、滑石粉、氧化铝和碳粉制备的多孔陶瓷在前驱体溶胶中进行浸渍负载,经干燥、煅烧制备得到多孔陶瓷基Li_4Ti_5O_(12),进行酸改性得到锂离子吸附剂,测定其对Li~+的吸附容量.实验结果表明,在一定范围内提高煅烧温度和增加保温时间有利于Li_4Ti_5O_(12)的生成,在750~800℃下保温5~8h得到的产品结晶度好、晶相纯度高.洗脱率和吸附容量随着煅烧温度和保温时间的增加而增加,在800℃下保温5h得到的样品经过酸洗后洗脱率为51.7%,对Li~+的吸附容量为12.2mg Li+/g Li_4Ti_5O_(12).     

硬脂酸凝胶法制备TiO_2纳米粉末及其表征

以硬脂酸、钛酸四丁酯为原料 ,用硬脂酸凝胶法制备了TiO2 超细粉末 .运用差热 热重 (DTA TG)、傅里叶红外光谱对制备过程进行了表征 ;用X射线粉末衍射 (XRD)、透射电镜 (TEM)对纳米晶的粒径和形貌进行了表征 .不同温度处理可得到不同晶型和形貌的纳米二氧化钛     

甘氨盐燃烧法制备BaFe12O19纳米粉末及其磁性能

以硝酸铁[Fe(NO3)39H2O]、乙酸钡[Ba(CH3COO)2]和甘氨酸[C2H5NO2]为原料,采用甘氨酸溶胶凝胶-自蔓延燃烧法成功制备成BaFe12O19纳米粉末;用XRD、SEM和VSM等测试方法研究了不同条件下产物的微观形貌、晶体结构及磁学性能。研究表明,煅烧温度和甘氨酸与金属盐的摩尔比会影响单相六角BaFe12O19的形成;甘氨酸与金属盐摩尔比为3∶1的前驱体在800℃下,煅烧2 h后可得到六角片状、粒度40~50 nm的单相BaFe12O19粉末;当温度升高到900℃时,钡铁氧体颗粒长大到100 nm以上,矫顽力下降。     

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.