LDPE/石墨复合材料的制备和性能

选用电导率、导热系数高的石墨(普通鳞片石墨FG、可膨胀石墨KP35、膨胀石墨EG35)对低密度聚乙烯(LDPE)进行填充改性,采用钛酸酯偶联剂NDZ101对石墨进行表面处理,提高石墨与聚合物基体的界面相互作用,制备出力学性能、导电、导热等综合性能优良的LDPE/石墨复合材料。结果表明:石墨的填充大大改善了聚乙烯的导电、导热和耐热性能,当石墨含量达20%时(文中的各种元素含量均指质量分数),LDPE/KP35的电导率达到1.91×10-7S/m,拉伸强度较LDPE有小幅提高,可作为导热抗静电材料推广应用。     

改性膨胀石墨对硬质聚氨酯燃烧性能的影响

本文采用磷元素接枝膨胀石墨(EG)制备了改性膨胀石墨(EGM),并研究其对聚氨酯泡沫(RRPUF)燃烧性能的影响。利用极限氧指数(LOI)和锥形量热研究了EGM对RPUF的阻燃性能的影响,通过扫描电镜和热重分析研究RPUF燃烧后残炭的微观形貌和阻燃机理。分析结果表明,RPUF/EGM的LOI和残炭量最高,热释放量和烟释放量均有大幅度的降低;RPUF/EGM燃烧生成的炭层也更加坚固致密。     

可膨胀石墨填充高回弹聚氨酯泡沫塑料的热性能

在原料中添加可膨胀石墨(EG),一步法合成高回弹聚氨酯泡沫(PUF).热导率试验表明,随着PUF内EG质量分数的增大,PUF的热导率呈现上升趋势.热重分析(TGA)试验表明,EG的膨胀与PUF的第一步热分解同时发生,EG使得PUF的两步热解略微延迟,但加速了PUF的热解速率,EG未参与PUF的热分解.差示扫描量热法(DSC)研究表明,EG膨胀之前其较小影响PUF吸热,但此后膨胀炭层延缓了PUF分解时热量的释放.利用动态热力学分析(DMA)研究了添加EG前后PUF的储能模量、损耗模量和损耗因子随温度变化情况,结果表明适量添加EG可提高PUF的阻尼性能.在750℃时高温裂解PUF,经气相色谱-质谱分析表明,添加EG前后的PUF分解产物的种类和质量分数相似.     

抗氧化性可膨胀石墨的制备及其阻燃性能

建立了一种抗氧化性可膨胀石墨的制备方法.采用正交实验及单因素实验确定了可膨胀石墨的适宜制备条件:天然石墨C与KMnO4、质量分数98％ H2SO4及Na4 P2O7的质量比为1.0∶0.20∶5.0∶0.60,反应前硫酸用去离子水稀释至70％(质量分数),在40℃下反应40 min,得普通可膨胀石墨(EG1);将EG1用去离子水洗涤脱色后,再用一定浓度的蔗糖硼酸脂镁溶液浸渍,经过脱水、60～80℃下干燥后得起始膨胀温度165℃、膨胀容积400 mL/g的抗氧化性可膨胀石墨(EG).通过氧指数测定、热重和差热分析等手段考察了该EG对线性低密度聚乙烯(LLDPE)的阻燃性能.结果表明:添加未经蔗糖硼酸脂镁处理的EG1为阻燃剂使LLDPE氧指数提高到26.1％;添加30％(质量分数)EG可以使LLDPE的氧指数提高到29.8％,而残炭量可由18.6％提高至23.4％,说明在高温下EG可形成高热稳定性炭层,从而实现良好的阻燃性能.进一步分析了LLDPE/EG/APP(Ⅰ)(聚磷酸铵)体系可能的阻燃机理,并考察了阻燃剂的加入对LLDPE的拉伸强度的影响.     

超声挤出制备聚对苯二甲酸乙二醇酯/膨胀石墨复合材料及其结晶和分散形态

采用超声挤出制备聚对苯二甲酸乙二醇酯/膨胀石墨复合材料(PET/EG),考察不同功率下复合材料的结构演变以及功率对复合材料熔融及结晶行为的影响.结果表明,超声辐照能使EG粒子尺寸减小,使其在基体PET中的分散更均匀.由于粒子的成核效应,PET/EG复合材料的结晶温度和结晶度都有所提高;引入超声后,复合材料结晶温度提高.TGA结果分析表明,超声辐照能提高PET/EG复合材料的热稳定性.     

可膨胀石墨/磷酸三氯乙酯协同阻燃硬质聚氨酯泡沫塑料的研究

本文研究了可膨胀石墨(EG)协同磷酸三氯乙酯(TCEP)对硬质聚氨酯泡沫塑料(RPUF)的阻燃性能的影响.采用极限氧指数(LOI)、烟密度等级(SDR)、热重分析(TGA)等方法进行测试.当RPUF中添加20%的EG/TCEP(质量比1∶1)时,RPUF的LOI值达到30.0%,比未添加时提高了13.4%.同时,SDR降低至55.49%,最大烟密度值(MSD)出现时间均比未添加阻燃剂和单独添加TCEP时滞后.TGA分析结果表明,添加EG/TCEP后RPUF的失重速率下降、残炭量增加,表明EG/TCEP能在RPUF中起到良好的协同阻燃效应.     

Mg(OH)_2/EVA纳米复合材料的界面改性研究

研究了马来酸酐接枝乙烯-醋酸乙烯酯共聚物(MEVA)对氢氧化镁/乙烯-醋酸乙烯酯共聚物纳米复合材料力学性能和阻燃性能的影响.通过TEM观察了氢氧化镁在复合材料中的分散性,SEM观察了复合材料的界面结合情况.结果表明:MEVA的加入显著提高了复合材料的力学性能和阻燃性能,当其在复合材料中的质量分数为8%时,复合材料的综合性能较好.     

含膨胀石墨的膨胀体系阻燃LLDPE/EVA复合材料的研究

将膨胀石墨(EG)、三聚氰胺(MEL)、多聚磷酸铵(ATP)与线性低密度聚乙烯(LLDPE)、乙烯醋酸乙烯酯共聚物(EVA)通过双螺杆挤出机熔融共混制备了阻燃复合材料。通过氧指数测定、水平燃烧测试、垂直燃烧测试、扫描电镜、热重分析仪研究了膨胀石墨(EG)的含量对复合材料的燃烧性能、燃烧机理、热稳定性的影响。结果表明,复配出的膨胀阻燃剂有良好的阻燃效果,EG的添加量为12.5%,EG、MEL、ATP配比为2∶1∶2时,复合材料达到难燃级别,阻燃机理满足膨胀成炭阻燃机理。EG含量的增加,复合材料热稳定性提高。     

使用膨胀石墨/ZnO复合材料去除水中甲基橙

分别加热醋酸锌和水洗后的可膨胀石墨、干燥后的可膨胀石墨和膨胀石墨(EG)的混合物,制备了3种不同的膨胀石墨/ZnO复合材料,分别记为EG/ZnO-1,EG/ZnO-2和EG/ZnO-3.使用X射线衍射分析(XRD)、扫描电子显微镜(SEM)和Branaucr-Emmett-Teller(BET)比表面积等技术对样品结构进行表征.在紫外线(UV)照射下,研究了EG/ZnO对水中亚甲基橙的去除效率.结果表明,EG/ZnO同时具有膨胀石墨的吸附功能和ZnO的降解功能.在3种EG/ZnO中,EG/ZnO-3对水中甲基橙的去除效率最高.使用EG/ZnO-3,甲基橙去除率受EG/ZnO-3热处理温度和ZnO含量的影响.在优化工艺条件下,经过3.5hUV照射,水中甲基橙可被完全去除.     

氢氧化镁/可膨胀石墨/聚丙烯复合材料的热降解过程与燃烧行为

以可膨胀石墨(EG)和氢氧化镁(MH)为无卤阻燃剂，通过熔融共混法制备了无卤阻燃聚丙烯(PP)复合材料(EG/PP、MH/PP和MH/EG/PP)，采用热重法研究了复合材料的热降解过程，以氧指数(LOI)和垂直燃烧(UL-94)评价研究了复合材料的阻燃性能，采用锥形量热仪研究了复合材料的燃烧行为.结果表明:MH和EG间存在显著的协同阻燃作用，在阻燃剂质量分数为60%时，MH与EG质量比为5 : 1的MH/EG/PP材料其氧指数可以达到29.7，与MH/PP复合材料相比提高了11.2%；EG与MH协同具有良好的降低热释放作用，与PP和MH/PP相比，MH/EG/PP复合材料的热释放速率峰值(peak-HRR)分别降低了73.9%和34.2%；EG和MH的协同作用大幅度降低了MH/EG/PP的质量损失速率；结合残炭的形貌结果，揭示了EG和MH协同阻燃机理的关键在于增强了炭层的隔热和隔氧作用.     

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.