脂肪族聚氨酯热稳定性的研究

利用热重分析及热重动力学方法研究了作者新合成的一系列新型聚酯型脂肪族聚氨酯的热稳定性.首次报导了它们的热重及热降解反应动力学特征参数,并讨论了硬段含量、合成方法及降解气氛等因素对脂肪族聚氨酯热降解反应的影响.实验结果表明:脂肪族聚氨酯的热降解反应呈多阶段性,硬段含量对其热降解反应的第一阶段有较大的影响.当硬段含量为30～40%时,热稳定性相对较强,其热降解反应表观活化能约为1160kJ/mol,热降解温度约为300℃.用一步法合成的脂肪族聚氯酯的热稳定性略优于用二步法合成的样品.与芳香族聚氨酯相比,脂肪族聚氨酯在受热时易受氧的进攻,因此采取相应的抗氧措施是提高脂肪族聚氨脂热稳定性的有效途径.     

SIS甲基丙烯酸甲酯接枝共聚物热降解动力学分析

用热分析方法研究了苯乙烯 -异戊二烯 -苯乙烯嵌段共聚物 ( SIS)与甲基丙烯酸甲酯接枝共聚物 ( SIS-PMMA)在 N2 气氛条件下的热降解动力学机理 .确定了标题化合物的特征分解温度 ,求得了热分解过程的表观活化能 ( E=2 70 .9k J· mol- 1 ) ,结果表明其热降解控制机理符合 Anti-Jander方程 :g( a) =[1 / ( 1 -a) 1 /3-1 ]2 .     

H_(12)MDI氨酯化反应动力学

依据—NCO与—OH二级反应特性,建立了动力学方程。采用二正丁胺滴定法,分别研究了4,4’-二环己基甲烷二异氰酸酯(H_(12)MDI)与聚四氢呋喃醚二醇(PTMG)、聚己二酸-1,4-丁二醇酯二醇(PBA)、1,4-丁二醇(BDO)在不同温度下的反应特性。研究结果表明:H_(12)MDI与PTMG、PBA和BDO反应活化能E a分别为60.9 k J/mol、113.0 k J/mol和42.2 k J/mol,H_(12)MDI与醇类化合物反应时活性较低。     

聚对苯二甲酸乙二酯(PET)—聚ε-己内酯(PCL)嵌段共聚物链的化学结构

以芳族聚酯(PET)为硬链段,以脂族聚酯(PCL)为软链段的聚酯一聚酯嵌段共聚物,由于聚合反应过程中同时存在多种酯交换反应,链的化学结构变复杂了.应用核磁共振技术(氢谱和碳谱)和应用几种模型化合物的研究证明,PET—PCL嵌段共聚物软、硬链段间的联接有两种方式,软链段有两种结构形式,而硬链段的结构单元也有两种类型,从而确定了PET—PCL 嵌段共聚物链的化学结构.     

热失重方法研究聚丁二烯聚氨酯降解动力学

用热重分析的方法，研究了一系列以端羟基液体聚丁二烯为软段的聚氨酯和尿氨酯的降解反应。在空气氛中，温度高于４００℃时有一急剧失重现象，致使得不到完整的失重曲线。在氮气氛中，降解反应分两个阶段进行。对降解的第一阶段，求出了有关热重数据。利用求得的降解反应表现活化能，比较了不同异氰酸酯结构和不同扩链剂样品的热稳定性。发现基于ＭＤＩ（４，４＇──二苯基甲烷二异氰酸酯）的样品热稳定性最好，基于ＴＤＩ（甲苯二异氰酸酯）的次之，基于ＨＤＩ（六次甲基二异氰酸酯）的样品，对热最不稳定。胺扩链的样品热稳定性较醇扩链的样品为好。     

在线分光光度法对Fenton降解活性蓝的降解动力学研究

利用在线分光光度法对活性蓝模拟废水的Fenton降解过程进行研究,探讨了过氧化氢浓度、二价铁离子浓度、温度、pH值和活性蓝浓度等因素对活性蓝降解的影响规律.结果表明Fenton降解过程分为两个拟一级动力学过程,反应初期降解速率常数(k1)和反应后期降解速率常数(k2)差约一个数量级.k1与Fe2+初始浓度线性正相关;H_2O_2初始浓度和pH值存在最佳值,分别为3.519 mmol/L和3;提高体系温度能够加快反应达到平衡的时间,反应活化能为25.21 k J/mol.     

线性端羟基聚氨酯弹性粘合剂热重动力学的研究

本文用热重分析研究了本所新研制的线性端羟基聚氨酯弹性粘合剂,利用作者新编的“热重动力学计算机程序包”,采用Coast—Redfern法,测定了四种样品的热重数据并首次报导了这四种样品在热降解两个阶段的动力学数据。在热降解第一阶段,反应级数n为0.7～1.4,热降解表观活化能E为127.14～135.84KJ/moi.,频率因子A为1.37×10~(12)～14.37×10~(12)秒~(-1)。在热降解第二阶段、反应级数n均为3,E为199.54～218.52KJ/mol,,A为2.99×10~(16)～5.35×10~(17)秒~(-1)。作者分别建立了四种样品在热降解两个阶段中的动力学方程,并估算了它们在不同温度下的使用寿命,建立了三种样品的热寿命经验公式。     

含苯并噻唑链段耐热环氧树脂材料的制备及其固化动力学研究

基于4,5-环氧四氢邻苯二甲酸二缩水甘油酯(TDE-85)或N,N,N',N'-四缩水甘油基-4,4'-二氨基二苯基甲烷(AG-80)与2-氨基苯并噻唑(ABZ)的固化反应,以分阶段升温保温方式制备含刚性苯并噻唑链段的TDE-85/ABZ和AG-80/ABZ耐热环氧树脂材料.DMTA分析显示,TDE-85/ABZ和AG-80/ABZ固化物玻璃化转变温度分别为473 K和495 K.而TGA分析表明,其最大热降解速率对应温度分别为618 K和643 K,在873 K下仍有11%和13%的残余质量.以非等温DSC法研究TDE-85/ABZ和AG-80/ABZ固化反应动力学得出表观活化能分别为67.72 k J·mol-1和63.57 k J·mol-1,证明TDE-85/ABZ和AG-80/ABZ固化反应是以自催化反应机理进行的,动力学数学模型与DSC实验数据相吻合.这可为TDE-85/ABZ和AG-80/ABZ材料在成型加工工艺参数的优化和选择提供技术支撑.     

自乳化含氟碳链水性丙烯酸酯共聚物的制备及性能表征

以含羟基或羧基或含氟烷基丙烯酸酯类单体与反应型乳化剂发生乳液自由基共聚,制备含羟基和羧基且可自乳化的水性含氟烷基侧链丙烯酸酯共聚物(WFP).经红外光谱、热重分析、差示扫描量热分析、凝胶色谱、粒径和黏度及扫描电镜的测试分析,表征了其结构与性能。结果表明,WFP有很好的热稳定性,其玻璃化转变温度为58℃,在氮气氛中热失重5%时对应的温度为151℃,最大热降解速率温度在403℃.WFP分子内存在因含氟长碳侧链段与聚丙烯酸酯,或与羟基、羧基、酯基等不相容形成微相分离平衡的结构效应,在涂布和水分挥发过程中含氟碳链段向气-液表面运动而聚集,显示出WFP可保护被涂覆的基材.     

烷基苯氯磺酸磺化反应动力学研究

本文对甲苯、乙苯和异丙苯的氯磺酸磺化反应速率和产物分布进行了对比研究.以甲苯为例,建立了烷基苯磺化二级反应动力学模型.研究结果表明:磺化反应速率与取代基给电子效应的强弱一致,空间位阻明显有利于对位产物生成.对、邻、间三种甲基苯磺酸异构体的活化能分别为24.49 k J/mol、23.54 k J/mol、48.17 k J/mol.对、邻、间三种甲基苯砜异构体的活化能分别为38.40 k J/mol、59.03 k J/mol、79.20 k J/mol.以上研究结果对优化反应工艺设计,提高产品制备效果具有重要理论指导作用.     

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.