微波辐射下固体酸催化合成异烟酸乙酯

在微波辐射下,以异烟酸和乙醇为原料,以活性炭固载对甲苯磺酸作催化剂,合成了异烟酸乙酯.最佳工艺条件:醇酸物质的量比为8∶ 1,催化剂用量为 1.0 g,微波辐射时间为 10 min,微波辐射功率为 200 W,酯化产率达 97.18%.另外通过实验发现,微波辐射下,反应速率及产率都明显高于常规加热方式.     

微波加热条件下氯化锌催化合成乙酸乙酯

以冰醋酸和无水乙醇为原料,氯化锌为催化剂,采用微波加热法合成乙酸乙酯.探讨了酸醇比、催化剂用量、微波功率和辐射时间对合成乙酸乙酯产率的影响.得出最佳的反应条件为酸醇摩尔比2∶1、催化剂质量百分数1.5%、辐射时间6 min和微波功率400 W,合成乙酸乙酯的产率为78.36%.     

微波辅助催化制备生物柴油的研究

研究在微波辐射下,脂肪酸和甲醇在自制催化剂作用下酯化反应制备生物柴油的工艺.结果表明:最佳工艺条件为微波输出功率160W,微波反应时间为110 min,醇油物质的量比为5∶1,催化剂用量为2.50g(相对于100 g的脂肪酸),在此条件下反应转化率达到97.08%.与水浴加热相比,采用微波辐射加热制备生物柴油的反应速度快、耗能少、转化率高.     

微波辐射纳米CeO2催化合成己二酸二丁酯

以己二酸和正丁醇为原料,以纳米CeO2为催化剂,利用微波技术合成了己二酸二丁酯.探讨了微波辐射功率、辐射时间、醇酸摩尔比及催化剂用量等对酯化反应的影响.实验结果表明:较佳的反应条件为:在己二酸用量为0.05 mol时,n (正丁醇):n(己二酸) = 3.0:1,纳米CeO2催化剂用量为反应物总质量的2.5%,微波功率为465W,辐射时间为10 min,酯化率达98%以上.     

微波辐射氯化铁催化合成乙酸乙酯

在微波辐射下以六水合氯化铁为催化剂合成了乙酸乙酯.探讨了酸醇物质的量比、氯化铁用量、微波辐射时间和微波功率对酯化率的影响.结果表明最佳反应条件为：酸醇物质的量比3∶1,氯化铁用量为酸醇总质量的4.0%~5.5%(1.2 g),微波功率280 W,微波辐射时间8 min.反应酯化率可达89.2%.     

微波辐射SnCl4／C催化合成草酸二丁酯的研究

以SnCl4/C为催化剂,以草酸和正丁醇为原料,微波辐射直接酯化合成草酸二丁酯.通过实验得出最佳反应条件为:醇酸摩尔比为3.5:1,催化剂用量为总投料量的2.5%,微波辐射功率480w,反应30min,收率可达96.8%.     

微波加热促进功能化离子液体催化合成柠檬酸三辛酯

以柠檬酸和正辛醇合成柠檬酸三辛酯为探针反应,咪唑类、吡啶类和季铵盐类具有丙烷磺酸基(-PS)功能基团的杂多酸盐作催化剂,在传统加热及微波加热方式下,分别考察了其阴阳离子对催化活性的影响.并选择最优催化剂[MIMPS]3PW12O40,研究了酸醇比、催化剂用量、反应温度和反应时间等对酯化率的影响.结果表明:杂多酸盐突出的特点是一种自分离催化剂,在传统加热和微波加热下都具有高活性,在反应温度为130℃时酯化率分别达到93.9％和93.5％.微波加热下[MIMPS]3PW12O40重复使用7次后酯化率保持在90％以上,表明该催化剂具有较高的反应活性和稳定性.     

微波辅助下联二萘酚酰胺催化剂在Biginelli反应中的应用

以合成联二萘酚酰胺类物质为催化剂,微波条件下对Biginelli反应进行研究;在乙醇作为溶剂,芳香醛、尿素和乙酰乙酸乙酯的摩尔比为1.2∶1.0∶1.0,催化剂1a的用量为15%mmol,反应温度60℃,微波加热25 min的条件下,化合物产率可最高达88%。此反应具有催化剂经济易得及用量少、反应条件温和、环境友好和操作简便等优点。     

微波辐射合成糠酸甲酯的研究

以糠酸和甲醇为原料用微波辐射的方法合成糠酸甲酯.其最佳反应条件为:微波辐射功率320 W,醇酸物质的量比为5∶1,催化剂盐酸用量为糠酸用量的21%,微波辐射时间12 min.结果表明,此法反应时间短,产率达87.4%.     

采用微波加热与共沸精馏分水联合方法合成松香丁酯

利用硫酸作催化剂,在微波加热与共沸精馏分水联合的新型酯化反应装置中合成松香丁酯。最佳反应条件为：正丁醇与松香的摩尔比为6：1、催化剂用量为松香用量的6％、反应时间为120min,微波功率为607．5W。粗产品酸值为52mgKOH／g,产率为92％。     

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.     

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…     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

<正>~~     

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。     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

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