三种单体在等离子体中的化学反应

本文对三种有机单体(MMA,MIB,VAC)等离子态下的反应产物进行了收集和分析。GC-MS测试表明产物由多种物种组成,ESR测试发现凝聚产物中有自由基存在。由产物分析推断了单体在等离子态下经历的反应历程。     

半纤维素热解反应的微观反应机理研究

采用密度泛函理论(DFT)方法,以半纤维素热解反应中的典型产物2-糠醛为切入点,对半纤维素模型化合物4-O-甲基-D-葡萄糖醛酸-D-木糖在温度范围(300~1100K)内进行了热解反应机理研究。研究发现,热解反应分为两个阶段,第一阶段为二聚体模型化合物的解聚,第二阶段为解聚后的两个单体分别反应生成2-糠醛的过程。计算结果表明:700K左右为二聚体模型化合物发生解聚的最佳温度,其支链发生分解反应的最大反应速率所对应的温度为500K左右,其主链分解反应的最大反应速率所对应的温度为700K左右。     

天然橡胶热解产物反应机理研究

针对天然橡胶初级热解(300～550℃)过程中的主要产物异戊二烯单体和二聚体-1,4-二甲基-4-乙烯基环己烯进一步热解生成小分子气体的生成机理展开研究,采用密度泛函理论对各个反应进行了模拟计算,得到了相关热力学参数焓变、自由能变以及动力学参数反应势垒;用Aspen plus建立一维裂解反应器模拟实验过程,得到产物分布情况。结果表明:单体的主要反应路径为氢基与单体之间的取代反应,主要产物为氢气,反应活化能为5.68kJ/mol,与通过热裂解工艺过程预测的产物分布结果相符;二聚体主要通道是先发生开环反应,然后与甲基发生取代反应,主要产物为甲烷,反应活化能为354.48kJ/mol。研究结果可为废旧轮胎的气化回收利用提供重要的理论依据。     

裂解气相色谱质谱法研究废旧ABS塑料的热降解行为

采用裂解气相色谱质谱联用技术对ABS塑料的热降解行为进行了研究.在氦气氛围中,500℃下对ABS进行热裂解,通过色谱质谱联用仪对裂解产物进行了定性分析,共鉴定出苯乙烯、甲苯和4-苯基丁腈等31种裂解产物.根据裂解产物信息和有机物热裂解反应的原理对ABS的热裂解反应机理作了探讨.ABS塑料的热降解过程是典型的自由基历程,解释了裂解产物中芳香烃类化合物、脂肪烃类化合物、腈类化合物和含溴酚类化合物的生成机理.ABS的高温降解过程不是三种结构单元降解过程的简单累加,三种结构单元在其降解过程中相互明显影响,最终导致裂解产物在结构和类别上的多样性.废旧塑料ABS热裂解过程会产生多种有害污染物,因此,选择合适的裂解工艺条件,既可得到更多有用的裂解产物,又可减少对环境的污染.     

QDTA/T/EGA/GC在线联同技术 Ⅴ.二烷基二硫代磷酸锌抗氧剂的热氧化分解机理的研究

采用文题和DTA与GC/MS不在线联同技术,对由正丁醇/异辛醇(1:1)合成的二烷基二硫代磷酸锌,研究了其热氧化机理。其热分解产物为:H_2S、COS、SO_2、n-C_4~-/i-C_4~-、i-C_8~-、C_4H_9SH、C_4H_9SC_4H_9、C_4H_9SSC_4H_9、C_4H_9SC_8H_(17)和C_4H_9 SSC_8 H_(17)等。分解分为三个阶段:①220—240℃为氧化诱导期,发生分子内异构化反应,在DTA曲线上出现一个显著的放热峰;②250—280℃,以热解为主反应的吸热过程;③280—300℃,以热解产物——硫醇进行热氧化分解为主反应的放热过程。反应机理为:由分子内异构化反应和β-氢原子内消除反应形成的热分解中间产物,经离子反应、自由基反应生成了组成复杂的各类最终产物。     

水溶性苝酰亚胺化合物电子转移与长寿命自由基阴离子的生成

利用紫外可见吸收光谱研究了一种结构新颖的以聚乙二醇(polyethylene glycol,PEG)链为取代基的水溶性苝酰亚胺化合物N,N’-二(聚乙二醇)-1-(4-巯基苯)苝酰亚胺(N,N’-Di(polyethylene glycol)-1-(4-mercaptobenzene)-perylene-3,4,9,10-tetracarboxylic diimide,BFL)的聚集行为,溶剂极性、表面活性剂对聚集行为有显著影响。结果表明:在水溶液中BFL在530 nm只出现一个与单体聚集体比例相关的特征峰;浓度增加,溶液中聚集体比例增加不明显;而有机溶剂和表面活性剂能够分散化合物,明显提高单体的数量。在水溶液中硫化钠使BFL发生电子转移反应,能够捕捉到超长寿命的中间产物一价阴离子自由基,之后BFL进一步被还原为二价阴离子。这种能够在还原反应中产生超长寿命自由基的特性使BFL成为优异的n型材料。     

Trolox及其酯化物与DPPH自由基的反应机理

通过1H和13C核磁共振及多种二维核磁共振谱,确定水溶性维生素E(Trolox)及Trolox丙酯与1,1-二苯基苦基苯肼自由基(DPPH·)在二甲基亚矾(DMSO)中反应的产物结构.根据的产物结构分析可知,两种抗氧化剂与DPPH·在DMSO中的反应机理有所不同.Trolox(或Trolox正丙酯)与DPPH·按相等浓度进行反应,即DPPH·自由基单电子氧化色满醇基团生成色满醇自由基中间产物;两个色满醇自由基进一步发生自岐化,生成一分子色满醇和一分子氧化形式.Trolox上的羧基与醌环相连生成环式的半醌结构,Trolox正丙酯则因羧基酯化被占用而生成醌式结构.     

六氟丙烷热分解性能及机理研究

在管式反应器中对六氟丙烷进行热分解,用气相色谱-质谱仪、气相色谱仪和化学滴定法对热分解气体进行分析。结果发现:六氟丙烷在600~800℃热分解时主要发生脱氟化氢(HF)反应,随着反应温度和停留时间的增加,六氟丙烷分解程度提高。根据均裂的化学键类型提出六氟丙烷热分解的5个初级反应路径,通过密度泛函理论DFT-(U)B3LYP/6-31G*计算六氟丙烷各化学键离解能,发现H转移反应所需活化能最低,C—C键断裂反应次之,分别为282.74和381.88 kJ/mol,表明六氟丙烷热分解过程中最易发生H转移反应脱去HF。在高温热分解气体中还检测到微量CF4、CHF3、CF2CHF等多种产物,分析是由H转移反应产物与C—C键断裂产生的自由基相互结合或者分解再结合形成。     

三氧化铬-乙酸与诺卜醇乙酸酯的反应研究

用三氧化铬的乙酸水溶液对诺卜醇乙酸酯进行了反应，反应的主要产物为质子酸作用下原料发生重排使四员环开裂并进一步水合生成的4—(1—甲基—1—羟基乙基)—1—环己烯—1—乙醇乙酸酯及该酯水解所生成的醇．对反应的其他产物进行色谱—质谱联机分析并对所得图谱进行解析后，确认了6个化合物的结构，它们是原料中的双键发生环氧化及进一步氧化桥头叔氢所生成的化合物，未发现双键断裂生成的四员环化合物。     

煤自燃过程气态产物产生机理

为了能够更加有效地利用气态产物预报煤的自燃过程,需要对煤自燃过程产生气体的机理进行深入研究.利用实验模拟出煤自燃气态产物的产生过程,得出其规律是:不同指标气体开始出现的温度不一样,同一指标气体在不同煤体中出现的温度不同.对煤低温氧化过程微观结构、自由基浓度与煤体温度之间的变化规律的分析,并以煤自燃自由基和逐步自活化反应为理论基础,提出了新的煤自燃过程气态产物产生机理,即煤中不同活性结构在不同温度下被活化发生氧化反应,在发生氧化反应时该类结构发生断裂形成自由基.不同自由基之间,自由基与氧之间相互发生反应,形成不同的指标气体从煤体中释放出来.图3,表4,参12.     

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).     

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.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.