漆树酶催化氧化愈创木酚

研究了漆树酶对愈创木酚的催化氧化,采用半制备HPLC及TLC对反应产物进行分离纯化,用光谱分析法鉴定产物结构.结果表明:漆树酶能使愈创木酚聚合为低分子聚合物,其中2种产物经鉴定为愈创木酚的四聚体和五聚体.     

水溶性有机介质中漆树酶催化氧化对茴香胺

采用分光光度法,考察不同水／水溶性有机溶剂体系中漆树酶的催化氧化性能,以及影响反应的因素．研究结果表明,漆树酶在醇溶剂中的活性要强于在非醇溶剂中,醇分子中羟基数量对漆树酶活性也有影响．在温度45℃,pH值为7．5,体积比为1：1的水／丙三醇溶液中,漆树酶的活力最高,活力比达150％以上,超出漆树酶在纯水中的活性．以漆树酶催化氧化对茴香胺,采用TLC和HPLC分离纯化反应产物．根据光谱分析法,鉴定主要产物为偶氮茴香醚．     

漆酶的活性测定及催化单取代Fc—R氧化反应

在二乙二醇单丁醚／磷酸盐缓冲液体系中，以二苯铁为底物，用分光光度法测定湖北毛坝漆树漆酶的活性无副产物干扰，该方法简便，准确，易行，考察了漆树漆酶对２９个单取代二茂铁衍生物和左旋多巴的催化氧化反应，发现了漆酶１４个新的底物，并讨论了它们的构效关系。     

联苯胺—H2O2—HRP伏安酶联免疫分析新体系酶催化反应机理？…

首次利用红外光谱法、紫外－可见光谱法对联苯胺－Ｈ２Ｏ２－辣根过氧化物酶（ＨＲＰ）伏安酶联免疫分析新体系酶催化反应产物进行了鉴定。结果表明，在ＰＨ４条件睛，ＨＲＰ能催化Ｈ２Ｏ２氧化联苯胺生成偶氮联苯胺，提出了相应的反应机理。     

漆树漆酶的催化氧化作用(Ⅻ)——儿茶酚胺氧化中间体的捕获

在静止条件下，用分光光度法对３个儿茶酚胺底物的漆酶催化氧化行为进行了考察．ＥＳＲ结果证明，这些底物在弱碱性条件下的漆酶催化反应经历了半醌自由基阴离子的阶段，Ｍｇ２＋离子的存在，提高了邻苯半醌自由基的动力学稳定性．结果还表明，儿茶酚胺底物的漆酶催化氧化产物，结构十分复杂，用二苯乙二胺只能捕获到少量对位羟基化的邻醌．     

有机介质中氯化血红素催化邻苯二胺氧化反应的研究

在正丁醇中,以氯化血红素模拟辣根过氧化物酶催化过氧化氢氧化邻苯二胺的反应,发现在正丁醇中氯化血红素具有过氧化物酶活性,能催化过氧化氢氧化邻苯二胺的反应,并可产生稳定的中间体.用紫外-可见光谱、红外光谱、HPLC串连质谱对产物和中间体进行了表征.结果表明,产物是2,3-二氨基吩嗪,中间体是比产物多2个氢原子的吩嗪类化合物.     

非水介质中辣根过氧化物酶失活过程

以辣根过氧化物酶催化酚类氧化反应为研究对象,考察了温度,含水量等因素对酶储存稳定性的影响以及反应过程中酶的失活动力学。结果表明,在低水环境的有机相中,酶的热稳定性显著提高;催化酚和过氧化物的氧化反应中,反应物和产物参与酶的失活过程,使失活速率增加;选择合理的反应条件,有助于减少失活,增加酶的使用周期。     

葡萄糖香草醛的相转移催化合成法

在葡萄糖香草醛结构－活性相关性研究中，进行了葡萄糖香草醛的合成工作。以溴代四乙酰葡萄糖和香草醛为原料，溴化四丁基铵为催化剂，采用相转移催化法进行糖甙化反应以９２％的收率得到四乙酰葡萄糖香草醛，经脱保护基后得到葡萄糖香草醛。产物结构经元素分析、红外光谱、核磁共振谱所证实。     

漆树漆酶的催化氧化作用：Ⅷ.四卤代氢醌的漆酶催化氧化

在静止条件下，对四卤代氢醌（ＴＸＱＨ２，Ｘ＝Ｃｌ，Ｂｒ，Ｉ）的漆酶催化氧化行为进行了考察结果证明，四卤代氢醌的酶反应具有几个明显特征：１）一级离解种是底物参与反应的必要形式；２）半醌自由基阴离子是反应的产物；３）半醌自由基经歧化转变成相应的醌；４）整个反应过程呈现出连串反应属性，这些特征反映了漆酶催化氧化反应的共性，结果还表明，由于卤原子的吸电子作用不强，不能使自由电子有效地离域，生成的半醌自由基     

三氟化硼及其硅胶负载物催化下酮类的Baeyer-Villiger氧化反应

考察了三氟化硼及其硅胶负载催化下30%H2O2对酮类的Baeyer-Villiger氧化反应.结果表明,两种催化剂都能在温和条件下催化酮类氧化得到相应的酯和内酯;小分子三氟化硼对2-金刚烷酮、环戊酮、2-甲基环己酮的催化氧化基本实现完全转化,产物内酯的选择性分别达到99%,99%和74%,其对链状的4-甲基-2-戊酮的氧化表现出较好的催化性能,相同条件下底物转化率和产物酯的选择性分别可达25%和99%;硅胶负载三氟化硼催化酮类Baeyer-Villiger氧化反应时,产物内酯的选择性很好,催化剂制备过程简单,并具有较好的重复使用性能.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

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.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the