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以FeSO4·7H2O和CoSO4·7H2O为原料,首先制备出晶粒细小的盐渍化碱式碳酸盐前驱体。在300—700℃焙烧1小时后,制备出CoF2O4纳米晶体材料,经XRD和TEM检测,粒径为10—40nm,粒度均匀 相似文献
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纳米晶体光电子性质研究进展 总被引:4,自引:0,他引:4
本文综述了近年来国内外纳米晶体光电子性质研究领域某些方面的进展情况,着重介绍了纳米晶体在光吸收、光致发光、非线性光学效应和电导率等方面的独特性能,这些研究表明,对于0 ̄3nm晶体(纳米晶粒处于分散介质中)来说,量子尺寸效应是产生晶体光电子性质突变的主要原因之一。对纳米晶体结构和性能的深入研究,能为光电子材料的发展提供新的途径和思路。 相似文献
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作者在从事晶体功能材料研究40余年、拥有厚重的学术与成果积累的基础上,全方位地审视了本领域学科前沿的研发热点与态势,提出了晶体功能材料发展的7个动向,即:1、单晶生长朝更大、更完整因而更难驾驭的方向发展;2、薄膜晶体是人工晶体的重要发展方向;3、薄膜晶体的制备正朝着材料元件一体化的方向发展;4、周期微结构材料的研制导致了光子晶体的面世;5、光子晶体己受到日益深切的关注并获得迅速的发展;6、微米晶和纳米晶已成为新的研究热点;7、智能晶体正逐步向我们走来。 相似文献
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纤维素纳米晶体(cellulose nanocrystal, CNC)具备高强度、高模量、结构可控、易于表面修饰、生物相容性、生物可降解性,在刺激响应功能材料的设计组装过程中扮演着越来越重要的角色。作为一类具有"智能"行为的大分子体系,刺激响应功能材料在受到外部环境的刺激时,能够做出灵敏响应,体现出设定的相应功能,CNC的引入不仅能够调控其力学性能,表面存在的羟基、羧基也为丰富材料的刺激响应源提供了便捷途径。本文从CNC的化学结构切入,介绍了CNC的特性及其构建的刺激响应功能材料的合成思路,并以刺激"开关"为主线,重点介绍了基于CNC的水、pH、热、光单一或多重刺激响应功能材料的研究进展,最后指出,提高纤维素纳米晶体表面修饰改性效率,拓宽多重刺激响应性,实现高性能的基于纤维素纳米晶体的多重刺激响应功能材料的制备是未来该领域的研究重点。 相似文献
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以FeSO4.7H2O和CoSO4.7H2O为原料,首先制备出晶粒细小的盐渍 化碱式碳酸盐前驱体。在300-700℃焙烧1小时后,制备出CoF2O4纳米晶体材料,经XRD和TEM检测,粒径为10-40nm,粒度均匀。 相似文献
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电沉积纳米晶材料的研究进展 总被引:9,自引:0,他引:9
本文介绍了电沉积法制备纳米晶材料的原理、方法与特点 ,综述了电沉积纳米晶材料的研究现状 ,讨论了电沉积纳米晶材料的应用与发展前景。 相似文献
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The magnetic properties of nanocrystalline hard magnetic and soft magnetic are summarized. When the grain size becomes of the order f the magnetic exchange length exchange coupling occurs. The different concepts of exchange coupling in these materials are discussed. Exchange coupling leads in isotropic hard magnetic materials to a remanence enhancement. Soft magnetic materials exhibit due to exchange coupling a lower coercivity, lower losses and consequently also improved properties. 相似文献
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The distortion structure in nanocrystalline NiAl is studied using molecular dynamics simulation.The rounded grain boundaries in these nanograins are a direct source for the observed lattice distortion.The change of grain size affects directly the volume fraction of the distorted lattice in the nanograin. 相似文献
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Synthesis and Characterizations of Nanocrystalline WC-Co Composite Powders by a Unique Ball Milling Process 总被引:2,自引:0,他引:2
Jun SHEN Jianfei SUN Faming ZHANGSchool of Materials Science Engineering Harbin Institute of Technology Harbin China 《材料科学技术学报》2004,20(1):7-10
In order to explore the high efficiency of fabricating nanocrystalline WC-Co composite powders, this paper presented a unique high energy ball milling process with variable rotation rate and repeatious circulation, by which nanocrystalline WC-10Co-0.8VC-0.2Cr3C2 (wt pct) composite powders with mean grain size of 25 nm were prepared in 32 min, and the quantity of the powders for a batch was as much as 800 grams. The as-prepared powders were analyzed and characterized by chemical analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential thermal analysis (DTA). The results show that high energy ball milling with variable rotation rates and repeatious circulation could be used to produce nanocrystalline WC-Co powder composites with high efficiency. The compositions of the powders meet its specifications with low impurity content. The mean grain size decreases, lattice distortion and system energy increase with increasing the milling time. The morphology of nanocrystalline WC 相似文献
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L.I. MedeirosA.B. Couto J.T. MatsushimaM.R. Baldan N.G. Ferreira 《Thin solid films》2012,520(16):5277-5283
In this paper, the morphological, structural and electrochemical properties of nanocrystalline diamond (NCD) films grown on carbon fibers (CF) were investigated. The CF substrates were produced at three different heat treatment temperatures (HTT):1000, 1500 and 2000 °C. The HTT variation promoted different organization indexes on the CF structures. Consequently, the NCD coating formation was strongly affected by the substrate HTT. The changes in the properties of the diamond films were discussed as a function of the film morphology evolution using CH4 flow rate of 0.25, 0.5 and 1.0 sccm in the feed gas. The X-ray diffraction measurements for the CF and NCD/CF composites were determinant to characterize the crystallinity of the NCD films as a function of the CF HTT and of the CH4 addition. Based on the diffractograms, the Scherrer's equation was applied to the (111) NCD peak, resulting in grain size values varying from 11.0 to 5.0 nm depending on the CH4 flow rate and on the CF HTT. The scanning electron microscopy images confirmed the deposition of a continuous NCD coating with high nucleation rate covering the whole CF, while their quality was analyzed by Raman spectroscopy measurements. The NCD grain agglomerates increased as a function of the increase in the CH4 flow rate from 0.25 to 1.0 sccm, showing similar film morphology to that of the unfaceted diamond balls obtained by chemical vapor deposition. This behavior confirmed the expected tendency by decreasing the diamond quality with the CH4 addition, especially for the films grown on CF treated at 1500 and 2000 °C. This performance was also corroborated by the cyclic voltammetry measurements concerning the electrode potential window and their responses in a redox couple. 相似文献
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目的 通过菌丝体材料的产品化设计实践,探索其设计原则与设计思路。方法 介绍菌丝体材料的特性并根据特性分析材料的可应用范围,阐述菌丝体材料的产品化现状及价值,并以材料驱动设计和可持续设计中的产品生命周期原则为理论依据,提出菌丝体材料产品化设计原则及设计思路。结论 总结出菌丝体材料产品化设计三原则,分别是材料的可持续性发展原则、产品的功能性与美观性兼具原则、创新产品的多样性原则,设计思路包括:认知菌丝体材料的特性;提出菌丝体材料的愿景;进行菌丝体材料的加工;测试菌丝体产品的功能;设计菌丝体产品的应用;探索菌丝体产品的可持续性。根据此原则与思路完成菌丝体板材设计,为今后的菌丝体材料产品化设计提供指导。菌丝体材料的产品化设计既可以拓展菌丝体材料的应用范围,规范菌丝体材料的设计流程,又能实现菌丝体材料的可持续性创新发展,为社会带来深远的环境和经济价值。 相似文献
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对位芳纶及其复合材料综述并产业化发展思考 总被引:1,自引:0,他引:1
对位芳纶由于其出色的性能,在宇宙探索、航空航天、国防军工、民用建筑等领域有大量的应用,尤其是芳纶复合材料已成为高科技领域必不可少的基础材料。对位芳纶复合材料具有轻质高强等突出特点,因此在节约减排方面具有显著效果,随着全球低碳经济的到来,芳纶及其复合材料的发展前景会越来越好。本文根据对位芳纶发展及应用的最新情况,详细介绍了对位芳纶的种类、性能、应用以及发展概况,并结合多年的对位芳纶研发及产业化经验,分析探讨了我国现有对位芳纶及其复合材料产业化发展方面存在的问题,指出我国在技术、生产效率、生产能力、设备、市场等方面与国外的差距,并据此提出对位芳纶及其复合材料今后的发展方向和研究重点。最后从科学发展观和低碳经济的角度,指出我国对位芳纶及其复合材料产业化发展的必要性和紧迫性。 相似文献
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感光材料的重要作用和发展历程 总被引:1,自引:0,他引:1
本文较系统地讨论了感光材料在国民经济中的重要作用,从产品技术、生产工艺、支持体技术、应用技术等方面较全面地介绍了感光材料技术进步的发展历程。 相似文献
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材料产业是资源(能源)消耗和污染排放的主要责任者之一,并由此产生了深刻的生态环境问题.从我国资源状况以及材料产业的发展现状出发,深入分析了材料产业面临的资源(能源)和环境压力,在此基础上提出了解决这些问题的一些基本原则. 相似文献