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自润滑复合陶瓷是极端环境服役运动部件的最佳候选材料之一,其中仿生层状结
构自润滑复合陶瓷由于具有优异的综合性能而倍受人们的青睐。基于宏/微观结构设计是实现其
结构/润滑功能一体化和可靠性提升的关键。本文结合作者所在课题组的相关工作,综述了层状
结构几何参数和界面微结构、参数与组分对氧化铝层状自润滑复合陶瓷力学性能、摩擦学性能
和服役可靠性的影响规律及作用机制,并提出了层状自润滑复合陶瓷的结构与界面优化设计准
则,以期指导自润滑复合陶瓷性能提升和推动其在高技术装备中的应用。 相似文献
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分形作为一种数学方法 ,其应用范围日益扩大 ,已经逐渐渗入各学科领域。本文简要介绍了分形的概念以及它在陶瓷微观结构中的应用情况 ,重点介绍了位错、晶粒度、晶界的分形 相似文献
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把弹性力学和断裂力学应用到颗粒弥散复相陶瓷的微观热应力分析中,对弥散相颗粒尺寸和体积分数的临界值进行了推导,并提出了颗粒弥散陶瓷微观结构及材质设计的一般性原则。 相似文献
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把弹性力学和断裂力学应用到颗粒弥散复相陶瓷的微观热应力分析中,对弥散相颗就尺寸和体积分数的临界值进行了推导,并提出了颗粒弥散陶瓷微观结构及材质设计的一艉性原则。 相似文献
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随着科技的迅速发展,对材料的性能提出了更高的要求,迫切需要开发新型轻质高性能结构材料,即低密度、高刚度、高强度和高韧性等特点集于一身。生物材料经过数亿年的进化,形成了与环境和功能需求相适应的精细复杂结构,如贝壳珍珠层的“砖-泥”结构和螃蟹角质层的螺旋结构,它们均表现出非凡的机械性能和独特的功能特性,这启发了人们对于高性能材料的设计和构筑。目前发展的冷冻铸造法(即冰模板法)是制备仿生材料的一种有效方法,通常在温度梯度作用下定向凝固水基陶瓷浆料,经冷冻干燥后可获得具有精细结构的多孔陶瓷材料,随后对该多孔陶瓷填充软相-树脂后可获得仿珍珠贝结构陶瓷-树脂复合材料。为了进一步控制材料微观结构,研究人员对冷冻铸造过程施加磁场作用,最终发现材料的结构和性能均发生了明显变化。本文介绍了冷冻铸造法在控制材料微观结构以及制备仿生材料方面取得的一些进展,综述了施加磁场作用对冷冻铸造的影响,总结了施加磁场辅助的冰模板材料微观结构和机械性能变化规律。 相似文献
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对分形艺术进行了讨论,展示了几种经典的分形图案,并通过将这些图案应用到碗、花瓶、花壶三种传统的陶瓷工艺品上的实例,揭示了分形几何和分形艺术在陶瓷界应用的巨大潜力。 相似文献
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Boyang B. Liu Srivats Srinivasachar Joseph J. Helble 《Aerosol science and technology》2013,47(6):459-469
The morphology of submicron flame-generated inorganic aerosols is known to be fractal-like with reported fractal exponents ranging from 1.1-2.5 for different materials. This wide range represents a correspondingly broad variation in structure and suggests that chemical composition might affect the final structure of flame-generated materials, a prospect of considerable importance in studies of submicron particulate penetration through electrostatic precipitators. To investigate this, the morphology of flame-generated submicron aerosols was studied by characterizing both fly ash generated in a pilot scale coal combustor and controlled composition inorganic aerosols generated in a bench scale flat flame burner. Fly ash generated during combustion of 2 bituminous coals at 2 different flame temperatures was found to be fractal-like with fractal exponents of 1.9-2 and fractal prefactors of 1.1-1.5. In addition, fly ash samples collected at the inlet and outlet of an attached pilot scale electrostatic precipitator yielded no difference in particle morphology, indicating a lack of structure-dependent penetration. Flame-generated silica, magnesia, sodium-doped silica, and magnesium-doped silica produced under identical conditions in an invariant premixed flame were also fractal-like in structure with fractal exponents of 1.7-1.8 and fractal prefactors of 1.6-1.8. No dependence of these structural parameters on chemical composition, flame residence time, or particle number density was observed over the ranges considered. Changing chemical composition did, however, lead to order of magnitude changes in primary particle diameter without any corresponding change in aggregate structure. Findings from both systems are consistent with a growth process governed in the late stages by cluster-cluster aggregation and indicate that for flame synthesized materials produced in the overall decreasing temperature gradient characteristic of coal combustors and industrial flame reactors, the aerosol aggregate structure will not be affected by changes in chemical composition under conditions of coalescence-limited growth. 相似文献
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锂离子电池用层状LiMnO2基正极材料的研究进展 总被引:4,自引:0,他引:4
层状LiMnO2材料因其结构不稳定、循环性能差,因而需对其进行掺杂改性.层状锰系衍生物具有比容量高、循环性能稳定等优点,已成为锂离子电池新的发展方向.介绍了目前对LiMnO2的掺杂改性研究,对多元层状锰基固溶体正极材料作了重点阐述.总结了近年来关于多元层状锰基正极材料的研究发展,介绍了其晶体结构、电化学性能、合成与制备技术,以及进一步的改性研究.如果多元层状固溶体材料的高倍率放电性能得到进一步的提高,则其必将成为新的一代锂离子电池正极的首选材料. 相似文献
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仿生材料是模仿生物形貌或分子结构并具有相似功能的合成材料,在水环境化学领域的研究中被广泛关注。综述了仿生材料在该领域的研究现状。首先,总结了仿生材料的构建方法,包括生物活性单元负载或重构、活性中心结构仿生、催化环境仿生和形貌仿生。其次,梳理了仿生材料在水中污染物的氧化去除、还原去除以及检测方面的研究进展。总体而言,其独特的结构、作用机制与优异效能使其具有较强的实际应用潜力,其微观结构与效能的相关关系及最优化结构的可控合成方法是后续研究要关注的关键问题。最后,论述了水环境化学领域中仿生材料研究所面临的挑战和未来的发展方向。 相似文献
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本文针对在防止微粒子粘附、表面保洁和防污方面的研究进展情况进行了综述,该类研究主要包括改进涂料的化学药剂组成及表面构造、涂料的改性、纳米技术的应用、光触媒技术的应用、从仿生学的角度结合生物的表面构造研制低表面能涂料等.在这些研究中,环境保护问题都得到高度重视.通过对这些文献的介绍,并根据它们的发表时间、所研究的技术和应... 相似文献
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Over the last 2 years the sol gel technique has become very popular because of its ability to yield multicomponent inorganic glasses at low temperatures. More recently techniques to incorporate functionlized organic species into a sol gel network of metal alkoxides have been developed and studied in our laboratory as well as others. Most of these studies have focussed on the structure-property behavior of these materials, with an emphasis on understanding the properties in terms of the level of microphase separation that occurs during the network buildup in these systems. While much has been gained in this respect, the desire exists to characterize better the structure of the inorganic phase in such systems, and in this respect, utilization of small-angle X-ray scattering profiles can provide information about this structure through fractal analysis. The work discussed here focuses specifically on the fractal character of specific ceramer materials produced as a result of the reaction between tetraethylorthosilicate and end-functionalized polytetramethylene oxide. It is shown that the cosolvent system utilized to compatibilize the reactants plays a very important role in development of the structure of the inorganic phase in these hybrid materials. 相似文献