壳聚糖分离乙醇／水溶液的渗透汽化性能

以脱乙酰化度为77．5％的壳聚糖为原料，采用高温浓碱处理的方法得到脱乙酰化度为98．2％的壳聚糖，分别用这两种壳聚糖制膜，用于乙醇／水混合物的分离结果表明，在同样条件下，脱乙酰化度高的壳聚糖膜的分离性能优于脱乙酰化度低的壳聚糖膜。     

壳聚糖脱乙酰化度的测定及反应条件对脱乙酰化度的影响

本文对壳聚糖在热浓碱作用下的脱乙酰化反应进行较详细的研究。     

壳聚糖化学改性条件的探讨

探讨了如何控制在均相条件下以高脱乙酰度的壳聚糖为主要原料,在乙酸水溶液-乙醇-吡啶介质中实现壳聚糖N位乙酰化反应的问题;制备了脱乙酰度为50%左右,具有良好水溶性的壳聚糖;重点研究了乙酰酐的用量、反应时间、反应温度、溶剂对脱乙酰度的影响.结果表明:乙酰酐用量与壳聚糖的摩尔比在2.0左右,温度为40℃,溶剂为乙醇时产物的脱乙酰度接近50%,反应时间为3小时.     

壳聚糖的改性及其自由基清除性能

介绍了不同相对分子质量、不同脱乙酰化度和O-改性壳聚糖的制备方法,综述了壳聚糖清除自由基性能的研究进展.总结了相对分子质量、脱乙酰度和O-修饰等因素对壳聚糖及其衍生物清除自由基的影响.     

微球形固定化α-葡萄糖苷酶的制备

将粉末状壳聚糖制备成微球形多孔载体 ,采用吸附 -交联的方法将TGL固定化 .研究表明 ,制备微球形多孔壳聚糖载体的关键取决于壳聚糖原料的分子量分布、壳聚糖的稀酸溶液浓度以及凝结液的组成等因素 ;当壳聚糖的相对分子质量为 3.0× 10 5左右 ,壳聚糖溶液浓度为 2 .5% ,凝结液组成为 2mol/LNaOH∶4 0 %甲醛 =3∶2 (体积比 )或2mol/LNaOH∶甲醇 =3∶1(体积比 )时 ,可制得微球形多孔壳聚糖载体 .最佳固定化条件研究表明 ,对于脱乙酰度为 88%的壳聚糖载体 ,加酶量为 3× 10 5Unit/g时 ,在 pH 6.0条件下 ,室温吸附 8h ,然后用 2 .0 %的戊二醛在 4 5℃交联 9h ,可得到固定化酶的活力为2 .34 2× 10 5Unit/g ,酶活力回收率为 78.1% ,并具有较好的强度 .     

壳聚糖在食品工业中应用的研究进展

壳聚糖是甲壳素脱乙酰化的产物,在食品工业中应用广泛。综述了国内外壳聚糖及其衍生物在食品工业中的重要作用和研究进展。     

甲壳素的脱乙酰化反应

研究了甲壳素的脱乙酰化反应时,碱溶液浓度、反应时间和反应温度等各种因素对反应产物的脱乙酰度、粘度和红外吸收光谱的影响。结果表明,随溶液中氢氧化钠浓度、反应温度和反应时间增加,甲壳素的脱乙酰化作用增加。甲壳素经一次反应的脱乙酰化度不超过90％。在较低温度和较短时间得到的壳聚糖在稀酸溶液中的粘度较高。     

不同脱乙酰度和分子质量的壳聚糖的抑菌性能

通过壳聚糖的抑茵实验和几种壳聚糖最低抑茵浓度的测定，比较了相同脱乙酰度不同分子质量以及分子质量相近但脱乙酰度不同的壳聚糖对金黄色葡萄球菌、枯草杆菌、大肠杆菌和假单胞菌的抑茵性能．结果表明：脱乙酰度相同、分子质量为400～800ku的壳聚糖，其抑茵能力随分子质量的增加而增强；而分子质量相近（均在430ku左右）、脱乙酰度不同（分别为68．4％，75．3％，83．6％和93．7％）的壳聚糖对上述4种细菌的抑茵能力差别不大；在pH值为5．5～6．0左右的条件下，壳聚糖具有最强的抑茵能力；实验条件下的壳聚糖对4种细菌都有较强的抑制作用，总体看来，壳聚糖对金黄色葡萄球菌的抑制作用最强，而对大肠杆菌的抑制作用相对较弱；实验条件下的壳聚糖对上述4种细菌的抑制作用普遍比苯甲酸钠强．     

壳聚糖在水处理中的应用

壳聚糖是天然聚合物甲壳素脱乙酰化产物,是一种具有重要开发研究价值的天然生物多糖资源。这里主要介绍了壳聚糖及其作为吸附剂、絮凝剂在水处理中的应用,指出开发壳聚糖作为新型水处理材料具有广阔的应用前景。     

高脱乙酰度、低粘度壳聚糖的研制

利用相转移催化剂与均匀设计探讨了高脱乙酰度、低粘度壳聚糖的制备方法，找出了最佳工艺条件，在最佳工艺条件下得到了粘度为２６．６ｍＰａ．ｓ，脱乙酰度为９９．４％的壳聚糖。     

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.     

A computer generator for randomly layered structures

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

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.     

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。     

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.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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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     

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