Effects of the reinforcement and toughening of acrylate resin/CaCO3 nanoparticles on rigid poly(vinyl chloride)

Novel composite particles based on nanoscale calcium carbonate (nano‐CaCO₃) as the core and polyacrylates as the shell were first synthesized by in situ encapsulating emulsion polymerization in the presence of the fresh slush pulp of calcium carbonate (CaCO₃) nanoparticles. Subsequently, these modified nanoparticles were compounded with rigid poly(vinyl chloride) (RPVC) to prepare RPVC/CaCO₃ nanocomposites. At the same time, the effects of the reinforcement and toughening of these modified nanoparticles on RPVC were investigated, and the synergistic effect of modified nanoparticles with chlorinated polyethylene (CPE) was also studied. The results showed that in the presence of nano‐CaCO₃ particles, the in situ emulsion polymerization of acrylates was carried out smoothly, and polyacrylates successfully encapsulated on the surface of nano‐CaCO₃ to prepare the modified nanoparticles, breaking down nano‐CaCO₃ particle agglomerates, improving their dispersion in the matrix, and also increasing the particle–matrix interfacial adhesion. Thus, the effects of the reinforcement and toughening of these modified nanoparticles on RPVC were very significant, and the cooperative effect of the nanoparticles with CPE occurred in the united modification system. Scanning electron microscopy analyses indicated that large‐fiber drawing and network morphologies coexisted in the system of joint modification of nanoparticles with CPE. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3940–3949, 2007     

Nanocrystalline CeO2 in SBA-15: Performance of Pt/CeO2/SBA-15 Catalyst for Water-gas-shift Reaction

CeO₂ particles confined within the pores of an SBA-15 mesoporous silica host were prepared by incipient wetness impregnation (IMP) and deposition precipitation (DP) methods. The materials were characterized by XRD, N₂-adsorption and temperature programmed reduction (TPR) to evaluate the structure, texture, and redox properties. The preparation procedure had significant impact on the assembling mode of CeO₂ inside the SBA-15 mesopores. A high dispersion of CeO₂ particles was achieved via DP, whereas the dispersion of CeO₂ prepared by IMP was found to be inhomogeneous and CeO₂ partially blocked the pores. The CO conversion in the water-gas-shift reaction was enhanced over 1 wt% Pt supported on CeO₂-modified SBA-15 obtained by DP.     

英汉情感隐喻的共性与差异

为进一步了解情感隐喻的实质,以人类基本情感的隐喻表达作讨论对象,对英汉语言中的基本情感隐喻进行共性与差异分析。     

跨文化交际中中式英语词汇层面的表现

从跨文化交际角度,分析了中式英语在词汇层面上的三种表现形式:望文生义、词汇冗余和文化词汇误用.认为中式英语的形成与思维方式差异和文化差异直接相关.     

金纳米线拉伸行为的分子动力学模拟

采用分子动力学方法模拟了不同截面尺寸金纳米线的拉伸力学行为。计算结果表明:相同长度的金纳米线弹性模量随着截面尺寸的减小而减小,而其屈服强度随着截面尺寸的减小而增大,并且发生屈服推迟现象。应力—应变曲线与形变过程相对应。在弹性变形阶段,纳米线形变不显著;随着应变量的增加,发现纳米线出现大量堆垛层错。     

声频谱测井仪器的研制和野外实验

研制成功的声频谱测井仪器在井下发射和接收三种频率的声波信号,其中发射和接收20kHz声波信号的声系有一个发射和四个接收探头,源距为2．1～2．568m,间距为0．156m;发射和接收40kHz声波信号的声系由一个发射和两个接收探头组成,源距1．0—1．5m,间距0．5m;发射和接收10kHz声波信号的声系由一个发射和两个接收探头组成,源距为2．168—2．668m,间距0．5m．用三种不同的频率的声波进行测量记录目的是获得井壁径向深度不同处介质的声学信息,而且不同频率的声波信号在岩石中传播过程中频谱变化也是井壁岩层的可用声学信息．在井下的信息采集、数据传输、地面记录和监控全部由计算机控制．该仪器已经在大庆油田的三口井中成功的进行了野外实验．     

VR技术对地下步行商业街心理环境辅助设计初探

文章力图以VR（虚拟现实）技术手段应用于城市地下步行商业街规划设计,来解决当前传统规划手段地下步行商业街规划中普遍存在的对其心理环境构筑的忽视和考虑不完善的诟病,以期最大限度消除规划设计中消极空间的产生,并对其关键技术进行了研究和探讨     

临川区土地生态环境安全评价研究

通过对临川区土地生态环境的研究,采用德尔菲法、等距划分法、加权指数法,确定该区域生态环境评价指标、权重、以及安全等级,得出临川区各乡镇的生态环境安全指数,为临川区土地生态环境安全建设提出建议。     

Molten salts/ceramic-foam matrix composites by melt infiltration method as energy storage material

A new type of high temperature energy storage material was obtained through the melt infiltration method, using compounding SiC ceramic foam as matrix and Na₂SO₄ as phase change material. The resulting composite material was measured by XRD, SEM, TG-DSC methods. The experimental results indicate that the composite is composed of silicon carbide, sodium sulfate and square quartz, and no chemical reactions occurs between Na₂SO₄ and SiC matrix. Na₂SO₄ has a good bonding with the SiC ceramic foam matrix. As the composite material is characterized by high thermal energy storage density and high thermal conductivity, it is suit for energy storage under high temperature. Funded by the “863” Hi-Tech Research and Development Program of China (2008AA05Z418)     

Damage and deterioration mechanism and curing technique of concrete structure in main coal cleaning plants

Concrete structures in main coal cleaning plants have been rebuilt and reinforced in the coal mines of the Shanghai Da-tun Energy Sources Co. Ltd., the first colliery of the Pingdingshan Coal Co. Ltd. and the Sanhejian mine of the Xuzhou Mining Group Co. Ltd. In these projects, the operating environment and reliability of concrete structures in the main plants of the three companies were investigated and the safety of the structures inspected. Qualitative and quantitative analyses were made on the spe-cial natural, technological and mechanical environments around the structures. On the basis of these analyses, we discuss the long-term, combined actions of the harsh natural (corrosive gases, liquids and solids) and mechanical environments on concrete structures and further investigated the damage and deteriorating mechanisms and curing techniques of concrete structures in the main coal cleaning plants. Our study can provide a theoretical basis for ensuring the reliability of concrete structures in main coal cleaning plants.