掺氮TiO_(2-x)N_x薄膜可见光激发光催化特性研究

采用反应磁控溅射法在玻璃基片上制备N掺杂TiO2-xNx薄膜和纯TiO2薄膜,对两种薄膜样品分别进行了300、400和500℃的退火处理,测试它们可见光激发光催化特性.在经过5 h降解苯酚的实验发现:经过同种温度退火处理的N掺杂TiO2-xNx薄膜比纯TiO2薄膜的可见光激发光催化降解苯酚效果要好,其中N掺杂TiO2-xNx薄膜经过400℃退火处理得到锐钛矿相薄膜对苯酚的降解率最高,达到50.4%,而纯TiO2薄膜经过400℃退火处理得到的同样是锐钛矿薄膜对苯酚的降解率仅37.8%.     

N 掺杂介孔 TiO2 的合成

通过简单的溶胶-凝胶方法合成了N掺杂的介孔TiO2.用X-射线粉末衍射(XRD)、扫描电子显微镜(SEM)、N2吸附、X射线光电子能谱(XPS)、紫外-可见(UV-vis)漫反射吸收光谱等手段进行了表征.X-射线粉末衍射表明,焙烧前的产物为无定形TiO2,焙烧后的产物为TiO2的锐钛矿.N2吸附-脱附等温线表明,N-20的BET表面积为76 m2/g,孔尺寸大约为10 nm,X射线光电子能谱(XPS)辅助证明有N掺入了TiO2中.紫外可见漫反射光谱(UV-vis)表明,N掺杂的介孔TiO2的吸收带边位置发生红移,吸光范围向可见光区拓宽.     

水解沉淀法制备氮掺杂TiO_2可见光光催化剂

为拓展TiO2可见光的响应范围,以氨水为氮源,在常温条件下采用水解沉淀法制备了氮掺杂TiO2粉末。以X射线衍射、紫外-可见漫反射吸收光谱和X射线光电子能谱等对TiO2进行了表征。对可见光照射下的光催化活性进行了测试,并考察了煅烧温度及掺杂量等对光催化活性的影响。结果表明:氮掺杂致使TiO2吸收边带向可见光区偏移,在降解亚甲基蓝的实验中表现出良好的可见光催化活性;随煅烧温度的增加,氮摩尔分数增加,晶粒增大,可见光催化活性减弱;煅烧温度为400℃,氮的摩尔分数为2%时制备样品的光催化活性最高。     

N/TiO_2可见光催化的氧化能力

以饱和尿素溶液水解沉淀工艺制备水合TiO2,再于温度600℃的空气气氛下煅烧2h,制得淡黄色的N/TiO2光催化剂,并以活性艳红X-3B、2,4-二氯苯酚及CH3COO-作模型污染物,着重研究了N/TiO2的可见光催化反应特性. XPS结果表明,掺杂N是以形成Ti-N化学键的形式进入了TiO2的晶格. UV-Vis结果表明,N/TiO2光催化剂对波长不低于400nm的可见光有明显的吸收效应. 光催化结果表明:N/TiO2在主峰420nm的荧光灯作用下,对活性艳红X-3B及2,4-二氯苯酚有明显的降解作用,但对CH3COO-无降解作用,然而当在主峰254nm或365nm的紫外灯作用下时能降解CH3COO-;激发光源波长在紫外区还是可见光区与光催化的氧化能力是密切相关的.     

氮对光催化性能的影响:TiO_2纳米球和纳米线对比研究

使用阳极氧化和氨气退火N化的方法制备了N掺杂的TiO2纳米球薄膜和纳米线薄膜.经过N掺杂TiO2纳米线薄膜与未掺杂纳米线可见光区的光吸收强度相差不大,能带宽度从未掺杂样品的3.2eV缩小为3.1eV.TiO2纳米球薄膜在可见光区的光吸收显著增强,能带宽度由未掺杂样品的3.2eV缩小为2.8eV,同时纳米球生长被抑制,其直径约为50nm,明显小于未掺杂TiO2样品的100mn.在可见光照射TiO2氮掺杂纳米线薄膜和纳米球薄膜降解4h后,溶液中亚甲基蓝的浓度分别降至45%和44%,N掺杂样品获得了优异的可见光光催化活性.研究表明N掺杂导致的O空穴浓度增加和能带宽度有效减小是其可见光区光催化活性增强的主要原因.     

铈掺杂对氧化钛薄膜光吸收性能的影响

采用电子束蒸发法制备铈掺杂的TiO2薄膜,研究掺杂铈TiO2薄膜的透过率,以及掺杂对TiO2薄膜光吸收性能的影响.实验发现掺杂CeO2使氧化钛薄膜的禁带宽度Eg从3.27 eV减小到2.51 eV,从而使光学吸收边从380 nm红移到495nm,大大提高了对太阳光或可见光的利用能力.     

尿素为氮源制备氮掺杂二氧化钛及其光催化性

为拓展二氧化钛对可见光的响应,以尿素为氮源,在温和条件下采用溶胶-凝胶法制备了氮掺杂二氧化钛粉末.用X射线衍射、透射电镜扫描、紫外-可见光漫反射吸收光谱和X射线光电子能谱等方法对制备的样品进行了表征,对可见光照射下的光催化活性进行了测试,并考察了煅烧温度及氮含量对光催化活性的影响.结果表明:氮掺杂致使二氧化钛在可见光区的光吸收增强,在降解甲基橙的实验中表现出良好的可见光催化活性;随煅烧温度的增加,氮含量减少,晶粒增大,可见光催化活性减弱;400℃下制备的样品中存在一个最佳的N/Ti配比,所对应的可见光催化活性最高.     

TiO2/VO2双层薄膜的制备及光电性能研究

文章采用磁控溅射法在玻璃基底上分别制备VO2单层薄膜与TiO2/VO2双层薄膜,并在Ar气中进行退火.用X射线衍射仪、扫描电镜、紫外-可见光分光光度计、LCR测试仪对薄膜样品的晶体结构、表面形貌、可见光透过率、电阻温度特性进行测试.结果表明,TiO2/VO2双层薄膜的相变温度降低到56℃,电阻温度系数为-1.087/℃,可见光透过率提高了20％～30％,且薄膜生长致密均匀.     

CdS/TiO2复合纳米管制备和光催化性能的研究

采用阳极氧化法在纯钛箔上制备TiO2纳米管,再通过连续离子层沉积法在TiO2纳米管上沉积CdS粒子,沉积3层CdS后,进行退火处理,退火后再沉积3层CdS.利用透射电子显微镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)和拉曼光谱对纳米管的形貌、物相结构和元素价态等特性进行分析.结果表明:经阳极氧化法制备的TiO2纳米管为锐钛矿结构,随后沉积的CdS同时出现了立方相与六方相晶格结构,400℃退火可以显著增加立方相CdS的结晶程度;纳米管中CdS粒子的直径均小于5 nm,CdS粒子由一大一小2个纳米粒子组成,大粒子由退火过程形成.光催化实验表明:经过退火处理的CdS/TiO2复合纳米管的可见光光催化能力约是未退火样品的3倍,说明退火处理可以有效提高TiO2可见光光催化能力.     

可见光响应氮-磷共掺杂TiO2纳米管制备及光催化性能

采用水热-浸渍两步法合成了一系列N-P/TiO2纳米管光催化剂,采用X射线衍射(XRD)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)和紫外-可见漫反射吸收光谱(UV-vis)等测试手段对其结构进行了表征.结果表明,300℃焙烧后的N-P/TiO2纳米管为锐钛矿相,氮和磷高度分散进入TiO2中.P和N掺杂含量分别为0.99%和0.56%.与纯TiO2纳米管相比,N-P/TiO2纳米管在可见光区的有较大的吸收,光吸收阈值产生红移.氮磷共掺杂可以明显提高TiO2纳米管的对甲基橙的光催化活性,其原因在于氮阴离子以N-Ti-O的结构进入TiO2,磷替换TiO2部份Ti4 ,从而降低了电子和空穴复合几率.     

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.