碳纳米预分散母胶粒对氢化丁腈橡胶定子材料性能的影响

通过添加不同质量份的碳纳米预分散母胶粒,研究不同配方对氢化丁腈橡胶力学性能、导热性能的改善。利用动态力学热分析仪、高低温伺服控制拉力机、扫描电镜等测试手段对橡胶的结构与性能进行表征。结果表明,添入15 phr的碳纳米预分散母胶粒,橡胶的拉伸强度、撕裂强度、断裂伸长率分别提升13.2%、44.7%、17.5%,压缩永久变形降低4%,100℃导热系数提升32%,150℃导热系数提升19%,动态力学性能的提升不是很明显,优化配方优异的高温力学性能来自于其导热系数的提高。

Hydrothermal treatment of metallic-monolith catalyst support with self-growing porous anodic-alumina film

Metallic-monolith catalyst support with self-growing porous anodic alumina(PAA)film was prepared by anodizing Al plate.The effect of hydrothermal treatment(HTT)on the crystalline state and textural properties of PAA film was investigated by XRD,BET,SEM and TG.The HTT treatment above 50°C and the subsequent calcination above 300°C could convert the amorphous skeleton alumina intoγ-alumina and increase the specific surface area(SBET).However,SEM images showed the HTT modification was a non-uniform process along the thickness of PAA film.The promotion effect of HTT on SBETwas non-linear,and the slope of SBETgradually decreased with the HTT temperature or time increased.The limited HTT effect should be attributed to a changed pore structure caused by an unfavorable pore sealing limitation.Pore widening treatment(PWT)before HTT could break the pore sealing limitation,because of the reduced internal diffusion resistance of hydrothermal reaction.The synergistic combination of PWT and HTT developed a PAA support with a large SBETcomparable to commercialγ-alumina.In the catalytic combustion of toluene,the Pt-based catalyst prepared by using the PWT and HTT comodified PAA support gave higher Pt dispersion and more favorable catalytic activity than that treated by HTT alone.The presence of a bimodal pore structure was suggested to be a decisive reason.

The Differences between Chinese Accounting Standards for Business Enterprises and International Financial Reporting Standards as well as the Convergence Strategy Method

The continuous development and progress of international economic integration has resulted in the increasing of economic and trade exchanges between various countries.In order to implement a more systematic corporate financial supervision mechanism effectively and adapt to the needs of economic development,it is necessary to clarify corporate accounting standards and international financial reporting standards.The relationship between them are crucial to improve the transparency of financial statements and optimize management levels.This paper analyzes the differences between Chinese business accounting standards and international financial reporting standards as well as discusses the convergence process and convergence strategy methods for reference.

碳纳米管/碳纤维跨尺度界面增强体系构建的研究进展

伴随着国防工业、先进装备制造等领域的不断发展,人们对复合材料的应用要求不断提高.碳纤维增强复合材料因其具备高强度、轻量化、长寿命的特点,与该领域材料的使用要求产生了高度适配.但在实际应用过程中,碳纤维惰性表面与聚合物基体间的弱界面结合严重影响了复合材料优异性能的充分发挥.构建微尺度、多维度碳纳米管/碳纤维界面增强体系被认为是提高相间结合能力的有效技术手段.本文综述了化学气相沉积、电泳沉积、化学接枝、浸涂喷涂4种较为成功的构建路线,讨论了碳纳米管在碳纤维表面的差异化微观沉积形貌所对应的不同界面增强机理,探讨了界面增强体系对复合材料综合性能的影响,并对该体系未来的构建和研究方向进行了展望.

碳纳米管填充聚合物基导热复合材料的研究进展

电子器件的集成度不断提高,对相关的热管理系统提出了更高的要求.高导热材料在热管理领域起着重要的作用.高分子聚合物因其轻质、廉价、良好的绝缘性和加工性,已成为制备导热材料的热门选择.在聚合物中填充高导热的无机填料是提高导热性能的有效手段.碳纳米管是一种具有一维管状结构和优异热学性能的碳纳米材料,在填充型导热复合材料中具有广阔的应用前景.本文综述了以碳纳米管为导热填料提升聚合物基复合材料导热性能的可行措施,分析了碳纳米管的本征结构以及在聚合物基体中的分布状态对复合材料导热性能的影响.最后,总结了碳纳米管填充聚合物基复合材料研究中仍需解决的关键问题,并提出了未来研究方向.

基于介孔氮掺杂氧缺陷型三氧化二铁正极的新型高性能可充放碱性锌电池

高效、环保、廉价的正极材料被认为是可充电碱性锌电池(RAZBs)的核心要素.据此,本工作开发出一种具有三维有序介孔结构、丰富氮掺杂和氧缺陷的三氧化二铁纳米材料(N-Fe_(2)O_(3)−x).该材料作为一种新型碱性锌电池的正极材料,表现出优异的性能.N-Fe_(2)O_(3)−x纳米材料采用独特的高等静压纳米铸造工艺和N_(2)等离子体活化方法制备,该材料具有高有效面积、丰富的活性位点、快速的电解质扩散通道和短电荷传输途径.以优化后的N-Fe_(2)O_(3)−x材料为正极,金属锌为负极制备的N-Fe_(2)O_(3)−x//Zn碱性锌电池具有高的容量(288 mA h g^(−1))和能量密度(135 W h kg^(−1),基于活性物质N-Fe_(2)O_(3)−x的重量计算).此外,该可充电锌电池具有良好的稳定性,在10 A g^(−1)电流密度下,1000次循环后仍有73%的电容保持率.该N-Fe_(2)O_(3)−x//Zn电池的电化学性能远远高于目前其他铁基锌电池.本工作首次利用三氧化二铁作为正极材料应用于可充电碱性锌电池的研究,其优良特性将吸引更多研究者的兴趣.

Assembly of plant communities in coastal wetlands--the role of saltcedar Tamarix chinensis during early succession

Aims The mechanisms of plant community assembly are hypothesized to vary at different stages of succession.Here,we explore the local assemblage structure of a herbaceous plant community at its early stage of succession in a supratidal wetland.specifically,we assess the role of Chinese saltcedar(Tamarix chinensis),the lone dominant shrub species,in shaping the spatial structure and species composi-tion in the local plant community,after landscape alteration.Methods We used the multivariate trend-surface analysis for analyzing the spatial structure of the community composition.a null model was also used to detect potential biotic interactions between species.statistical significance was derived from a permutation test by randomizing the presence-absence matrix and functional traits independently.sensitivity analysis by randomly selecting 50 subplots and repeating the null model tests was also done.Finally,rank correlation analysis was used to study the relationship between effect sizes and distance to nearest T.chinensis individuals.Important Findings The herbaceous plant community was highly structured and shaped by the presence of T.chinensis.at local scale,two functional traits,plant height and leaf area,were found to be significantly convergent.Dispersal,environmental stress and interspecific competition played a trivial effect on the local community assembly.The facilitating effect of T.chinensis on the pioneering herbaceous plants,through acting as a wind shelter,was put forward as the dominant community assembly process.