pH和取代基团对席夫碱电化学氧化还原的影响

合成了5种不同结构的席夫碱(N-苯基苯甲亚胺、具有-OH基团的N-苯基-2-羟基苯甲亚胺和N-(2-羟基)苯基苯甲亚胺、具有-NO2基团的N-苯基-4-硝基苯甲亚胺和N-(4-硝基)苯基苯甲亚胺).利用循环伏安法对5种席夫碱水溶液在玻碳电极上的电化学氧化还原行为进行了研究.同时考察了pH对席夫碱-CH=N-基团的电化学...     

青蒿素在不同电极上的电化学行为及其在血红素作用下的还原

 在20%的乙醇和B-R缓冲溶液(pH为7.2)中,分别比较了青蒿素(artemisinin,qhs)在金电极、银电极、铂电极、玻碳电极上的电化学行为,结果表明:在+0.00～-1.30V(vs.SCE)的电位范围内,青蒿素在金电极和铂电极上无氧化还原峰信号;而在银电极和玻碳电极上有一还原峰,无氧化峰,峰电位为分别-0.64V和-0.91V.此外在银电极和玻碳电极上,血红素(hemin)能够催化青蒿素的还原.     

糠醛在碳纳米管修饰电极上的电化学行为

采用N,N-二甲基甲酰胺分散碳纳米管（CNT）,制备碳纳米管修饰玻碳电极．运用循环伏安法和Tafel曲线法,研究了糠醛在碳纳米管修饰玻碳电极上的电化学行为．实验结果表明：在浓度为0．1mol／L的磷酸盐缓冲溶液（pH6．8）中,碳纳米管修饰电极对糠醛具有良好的催化作用．在扫速为50-1000mV／s的范围内,糠醛的还原峰电流与扫速的平方根成良好的线性关系,表明糠醛在碳纳米管修饰电极上的氧化还原过程是受扩散控制的．在pH值为4-10的范围内,随着pH值的增大,糠醛的还原峰电位逐渐负移．通过Tafel曲线、峰电位与pH值的线性关系,计算得到电化学过程中参加反应的电子数为2,质子数为1,电极反应的电子转移系数为0．644．     

吡柔比星在玻碳电极上的电化学行为研究

研究了吡柔比星（PB）在玻碳电极上的电化学行为,结果表明：在0．1mol／LHAc-NaAc缓冲溶液（pH=6．0）中,吡柔比星在-0．56V有一良好的还原峰。用循环伏安法研究体系的电化学行为,该体系属准可逆过程。同时测定了该电化学过程的动力学参数：电子转移系数α为0．51,扩散系数D为2．72×10^-5cm2^／s。     

两个新的二茂铁基席夫碱衍生物的合成、表征及电化学性质

以二茂铁间(对)苯胺为原料，合成了两个新的二茂铁基席夫碱衍生物FcL1[N-(2-羟基亚苄基)-3-二茂铁基苯胺]和FcL2[N-(2-羟基亚苄基)-4-二茂铁基苯胺]，通过元素分析，IR，UV和^1HNMR光谱分析等确证了标题化合物的结构．电化学研究表明：FcL1和FcL2的电化学性质相似，亚胺基团的引入显著影响了二茂铁的式量电位，同时，茂环上取代基的氧化会导致电极的钝化．此外，利用多种电化学手段测定了标题化合物在CH3CN中的扩散系数(D)和标准电极反应速率常数(ks)．     

维生素B2在电化学预处理玻碳电极上的电化学行为及其痕量测定

用阳极氧化和循环扫描的方法电化学预处理得到的玻碳电极（PGCE）有一对可逆的氧化还原峰（Epa=-0.073V,Epc=0.044V)。PGCE能大大提高水溶性的维生素如维生素B2（VB2）的电化学响应。实验表明VB2在PGCE上是吸附行为。PGCE具有很强的稳定性，用其能测定痕量的VB2和复合维生素片剂中的VB2，结果令人满意。     

纳米二氧化锰在玻碳电极上的直接电化学行为研究

将纳米MnO2修饰于玻碳电极表面,研究了纳米MnO2在玻碳电极上的直接电化学行为.实验结果表明:固载纳米MnO2的玻碳电极在pH为9.48的NH3-NH4Cl的缓冲溶液中于0.0～0.8 V(vs SCE)的电位范围内出现一对峰形较好的不可逆氧化还原峰,其氧化过程在较低扫速时属吸附-扩散混合控制,此时阴极传递系数α=0.547 7,阳极传递系数β=0.452 3,在较高扫速时属吸附控制.同时在pH=8.0～10.5范围内其氧化峰电位与pH值呈现较好的线性关系.     

聚1-[3’-(N-吡咯)丙基]-3-丁基咪唑离子液体膜电极测定双酚A

合成了1-[3＇-（N-吡咯）丙基]-3-丁基咪唑离子液体,采用电位阶跃技术制备了该离子液体聚合物膜修饰玻碳电极,利用扫描电子显微镜（SEM）和交流阻抗谱（EIS）表征了该膜修饰电极的表面形貌和电化学性能,通过伏安法研究了双酚A在该膜修饰电极上的电化学行为.结果表明：双酚A在聚离子液体膜修饰电极上只有一个不可逆氧化峰,氧化峰峰电流比在裸玻碳电极上显著增强.峰电流与双酚A浓度在1.0×10-8～1.0×10-5mol/L之间线性关系良好,检出限为8.0×10-9mol/L（S/N=3）.该法可用于测定塑料瓶中双酚A.     

聚苯胺在离子液体中的电合成及其电催化性质

以离子液体1-丁基-3甲基咪唑四氟硼酸盐（BMIMBF₄）作为溶剂及电解质,运用循环伏安法在玻碳电极上实现了电化学氧化聚合苯胺.聚苯胺膜修饰玻碳电极在空白离子液体及酸性溶液（pH＝0～4）中均有较好的响应,并且对邻苯二酚及对苯二酚有很好的电催化效果.     

碳原子线修饰电极对尿酸的电催化作用

通过循环伏安法和差分脉冲伏安法研究了碳原子线（CAW）修饰电极对尿酸电化学反应的催化作用.研究发现,在含有0.5 mmol/L尿酸的pH=6.8的0.1 mol/L PBS缓冲溶液中,尿酸在CAW修饰电极上的氧化峰电位比裸玻碳电极上的氧化峰电位负移0.049V,而氧化峰电流ipa比裸玻碳电极增加了3.96倍,说明碳原子线修饰电极对尿酸的电化学过程具有很好的催化作用.     

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.