固定化乙酰胆碱脂酶的研究

以戊二醛为交联剂,将乙酰胆碱脂酶交联固定到硅胶载体上,研究了影响固定化酶的主要因素．通过酶活力的测定,确定了最佳戊二醛浓度、pH值、固定化时间、酶用量、固定化酶的最适作用温度、pH值、酶的稳定性及其回收率．结果表明：戊二醛浓度为0．5％,pH值为8．0,固定3．0h,酶与载体比例为30mg／g可制备良好的功能化载体．固定化乙酰胆碱脂酶最适作用温度和pH范围分别为40℃和6．0～9．0．重复使用10次固定化酶,回收率约为70％．     

聚乙烯醇-海藻酸钠共固定化葡萄糖氧化酶和过氧化氢酶

酶的固定化是提高酶的稳定及降低使用成本的重要途径．通过制备聚乙烯醇(PVA)-海藻酸钠(SA)复合载体,对共固定化葡萄糖氧化酶(GOD)和过氧化氢酶(CAT)的条件进行了研究,优化了固定化酶制备工艺,研究了固定化酶性质．得出制备固定化酶最佳条件为：载体比例 PVA∶SA＝9．0∶1．5,加酶量10 mg/mL,酶活之比CAT∶GOD＝10∶1．固定化酶的最适反应温度为45℃,比游离酶提高了5℃,最适反应pH 没有发生变化,连续使用6次酶活保留60％．研究结果有一定的应用潜力．     

四氧化三铁吸附包埋固定辣根过氧化物酶及其应用

建立了Fe₃O₄吸附包埋固定辣根过氧化物酶,并与明胶、开孔明胶、海藻酸钠3种不同的固定化方法载体进行了比较,发现该固定化方法具有较高的固定效率。对固定化酶与自由酶的稳定性进行了比较,发现Fe₃O₄吸附包埋固定化HRP的稳定性高于其他固定化HRP和自由酶。此外,测定了不同戊二醛浓度、交联时间、给酶量、Fe₃O₄使用量及明胶浓度对 辣根过氧化物酶固定效果的影响。结果表明,固定化反应的最佳条件如下：最佳给酶量与Fe₃O₄用量比例约为95u HRP/g Fe₃O₄,最佳Fe₃O₄用量与凝胶比例为1.0g Fe₃O₄/10mL 10％～20％,最适戊二醛浓度和交联时间分别为0.5％和30min。在此条件下制备的辣根过氧化物酶 活性约为1.1u/g,酶活固定率约为15％。该固定化酶重复应用于PCP催化去除反应,可获得稳定的PCP去除率。     

聚多巴胺辅助磁微球固定β-葡萄糖苷酶的制备与应用

通过溶剂热法和改进的St?ber水解法制备了Fe_3O_4@SiO_2磁性纳米粒子,并用透射电镜对纳米粒子进行了表征.采用聚多巴胺辅助法将β-葡萄糖苷酶固定在磁性纳米粒子上.具体考察了加酶量、多巴胺质量浓度和固定化时间等因素对酶活和酶固定率的影响规律,获得了β-葡萄糖苷酶固定化的最适条件.结果表明,当加酶量为50,U/g、多巴胺质量浓度为1.6,mg/m L、固定化为24,h时,所制备的固定化β-葡萄糖苷酶活力为25.01,U/g,明显优于传统戊二醛交联固定的β-葡萄糖苷酶活力.     

棉纤维膜上高碘酸钠法固定化脂肪酶

研究了棉纤维膜上高碘酸钠法固定化脂肪酶的工艺条件,并考察了固定化脂肪酶的温度、酸度以及间歇操作稳定性。通过实验给出了固定化酶的最佳条件：NaIO4浓度为0．2mol/L,交联时间24h,pH值为9左右,酶的质量浓度6．0g/L,固定化酶最在活力7．38U/cm^2。该固定化酶最适应的温度为35℃,pH＝8．0,t1/2=168h。     

陶瓷-壳聚糖复合材料固定真菌漆酶

以陶瓷为第一载体,壳聚糖为二次载体,戊二醛为交联剂,采用共价结合和吸附联用法制备固定化漆酶。考察了漆酶固定化的影响因素,并对固定化漆酶的性质进行了研究。结果表明,漆酶固定化的适宜条件为0.15g壳聚糖-陶瓷复合载体,加入3mL 1.25?mg/mL漆酶磷酸盐缓冲溶液（0.1mol/L, pH4.0）,在4℃固定24h。酶的固定化效率是51.0%,固定化酶的酶活是55.87U/g,最适pH为3.0,最适温度分别为25℃和50℃。该固定化酶具有良好的贮存和操作稳定性。在pH3.0,温度25℃时,固定化酶对2,2-连氮基-双-(3-乙基苯并二氢噻唑啉-6-磺酸)二铵盐的表观米氏常数为66.64μmol/L。     

固定化木瓜蛋白酶的研究及其应用

从8种载体材料中选取自制的氨基含量约2．878mmol/g的甲壳质作为固定化载体,采用吸附交联法,以戊二醛为交联剂,对木瓜蛋白酶进行固定化。17．5mg/g的固定化酶／载体比较,pH6.5,5℃下,先吸附10min,再以0．7％的戊二醛终浓度交联12h,所得固定化酶酶活回收可达52．0％,酶活力为3．54U／g。固定化酶在65℃以下,溶液酶在55℃以下稳定;固定化酶在pH7.0以下稳定,溶液酶在pH6.0以下稳定;5℃条件下,固定化酶贮藏半衰期为183d;以酪蛋白为底物,固定化酶的操作半衰期可达27d。用固定化酶水解甲壳胺,产物分子量小于10 000的甲壳胺低聚糖得率约为45．55％。     

壳聚糖固定化云芝漆酶的制备及特性

以壳聚糖为载体,戊二醛为交联剂制备固定化漆酶,测定了不同戊二醛浓度、交联时间、给酶量以及固定化时间对固定化漆酶活性的影响。结果表明,固定化反应的最佳条件为戊二醛浓度5%,交联时间8h,给酶量20mg/g载体,固定化时间6h,在此条件下制备的固定化漆酶酶活性保持率为52.2%。此固定化漆酶具有最大活性时的溶液pH值在4.5,相比于自由漆酶的最佳pH值5.0,其向酸性偏移;与自由漆酶相比,固定化酶有很好的稳定性和可重复使用性。     

静电纺PA6/PVA纳米纤维及其纤维素酶的固定研究

利用静电纺丝技术制备PA6/PVA纳米纤维.通过环氧氯丙烷法活化羟基,将纤维素酶固定于PA6/PVA纳米纤维上.考察固定化纤维素酶和自由纤维素酶的酶活,研究固定化纤维素酶的酶学性质.结果表明:自由酶的最适反应温度为55℃,而固定化酶的最适反应温度为65℃,比自由酶的提高了10℃;与自由酶相比,固定化酶的活性随pH值的变化曲线明显变宽,热稳定性显著增强;固定化纤维素酶在4℃下能长时间保持较高的活力.     

酸性木聚糖酶交联酶聚集体的制备条件优化

交联酶聚集体法是一种新型的无载体酶固定化方法,为提高酸性木聚糖酶的稳定性,使用该法固定化微紫青霉产酸性木聚糖酶,制备无载体固定化木聚糖酶,并对其制备条件进行优化。结果表明,优选的制备条件为将质量浓度0.36mg/mL的酸性木聚糖酶粗酶液在冰水浴中经饱和质量分数为85%的硫酸铵沉淀30min后,于40℃,加入终体积分数为0.14%的戊二醛,交联4h可获得较高活性的交联酶聚集体,酶活保留率达42.2%。这有助于酸性木聚糖酶更好地在工业中应用。     

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

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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