共查询到20条相似文献,搜索用时 46 毫秒
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沉淀法制备纳米级粒子的研究——化学原理及影响因素 总被引:34,自引:0,他引:34
本文详细介绍了沉淀法制备纳米级粒子的化学原理,重点讨论了反应物浓度,反应温度,表面活性剂,pH值及反应时间等诸因素对粒子大小,形状的影响。 相似文献
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姜娈 《合成材料老化与应用》2011,40(3):36-40
近年来,超顺磁性纳米粒子以其独特的磁响应性和良好的生物相容性,越来越引起科学工作者的重视,本文专门对超顺磁性纳米粒子的制备加以论述,分别介绍沉淀法、溶胶-凝胶法、微乳液和反相微乳液法、水热法、多元醇还原法、化学气相沉积法、化学气相凝聚法、等离子蒸发法、机械球磨法、蒸发冷凝法和磁控溅射方法等合成磁性纳米粒子的方法及特点,... 相似文献
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纳米粒子(又称团簇、超微粒、超小粒子、量子点等)一般是指尺寸在1~100nm之间的粒子,是处于原子簇和宏观物体交界的过渡区域,从通常的关于微观和宏观的观点看,这样的系统既非典型的微观系统亦非典型的宏观系统,是一种典型的介观系统。纳米材料具有明显的表面效应、体积效应、量子尺寸效应和宏观隧道效应,这些不同于体相材料和单个分子的特性,使其在陶瓷、化工、电子、光学、生物、医药等许多方面有重要的应用价值。自80年代以来,纳米粒子的研究已成为世界性的热点之一。本文对钴及其化合物纳米粒子的制备、特性及应用等方面作一综述。 1 制备 纳米粒子制备方法很多,传统的物理方法 相似文献
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聚合物\无机纳米粒子复合材料研究进展 总被引:36,自引:6,他引:36
本文介绍了纳米粒子的一些特性及聚合物基纳米复合材料的研究现状,着重介绍了无机纳米粒子填充聚合物复合材料的制备方法、性能及应用前景。 相似文献
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采用液相化学还原法,以硫酸铜为原料,抗坏血酸作还原剂,吐温-80作修饰剂,用正交实验方法获得了油溶性纳米铜的最佳的合成条件:抗坏血酸为3 g,吐温-80为30 mL,正丁醇为70 mL,反应温度95℃。并利用X射线衍射仪对产品进行表征测试。 相似文献
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尖晶石纳米催化剂应用于烯丙醇多相氧化制烯丙醛或烯丙酮 总被引:2,自引:0,他引:2
使用共沉淀法通过Ru对MeFe2O4的同晶取供制备了纳米级MnFe1.95Ru0.05O4催化剂。在通过过渡金属进一步改性该催化剂的过程中,发现MnFe1.95Ru0.05O4的催化剂性能优异于文献报道的其他多相醇氧化催化剂,XRD测试表明该催化剂仍保持尖晶石结构。该纳米催化剂能有效地将不同烯丙醇类氧化成烯丙醛类或烯丙酮类,与文献报道的其他多相氧化催化体系相比,该催化剂具有更高的活性转换数。借助于EXAFS等表征结果和1-辛醇与4-辛醇的竞争反应,判断出单核的Ru类反应的活性中心,EXAFS的表征同时表明由于Cu的添加而产生的Ru=0能加快反应速率。作者在此基础上提出反应机理,认为Ru在反应过程中形成醇化物,再经过β消除反应生成相应的醛或酮。 相似文献
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Torsten Hegmann Hao Qi Vanessa M. Marx 《Journal of Inorganic and Organometallic Polymers and Materials》2007,17(3):483-508
Revolutionary developments in the fabrication of nanosized particles have created enormous expectations in the last few years
for the use of such materials in areas such as medical diagnostics and drug-delivery, and in high-tech devices. By its very
nature, nanotechnology is of immense academic and industrial interest as it involves the creation and exploitation of materials
with structural features in between those of atoms and bulk materials, with at least one dimension limited to between 1 and
100 nm. Most importantly, the properties of materials with nanometric dimensions are, in most instances, significantly different
from those of atoms or bulk materials. Research efforts geared towards new synthetic procedures for shape and size-uniform
nanoscale building blocks as well as efficient self-assembly protocols for manipulation of these building blocks into functional
materials has created enormous excitement in the field of liquid crystal research. Liquid crystals (LCs) by their very nature
are suitable candidates for matrix-guided synthesis and self-assembly of nanoscale materials, since the liquid crystalline
state combines order and mobility at the molecular (nanoscale) level. Based on selected relevant examples, this review attempts
to give a short overview of current research efforts in LC-nanoscience. The areas addressed in this review include the synthesis
of nanomaterials using LCs as templates, the design of LC nanomaterials, self-assembly of nanomaterials using LC phases, defect
formation in LC-nanoparticle suspensions, and potential applications. Despite the seeming diversity of these research topics,
this review will make an effort to establish logical links between these different research areas. 相似文献
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通过考察酮康唑固体脂质纳米粒体外透皮情况,由结果预测固体脂质纳米粒的发展前景.方法制备酮康唑固体脂质纳米粒,并测定2h、4h、6h、8h、12h、24 h时间点的药物累积透过皮肤与潴留于皮肤的量,通过数据分析评价药物在固体脂质纳米粒里的体外释放及透皮情况.结果药物在固体脂质纳米粒里的皮肤累积透过量低于含药1%的乳膏,但固体脂质纳米粒的皮肤潴留量明显高于含药1%的乳膏.结论固体脂质纳米粒可增加药物在皮肤的局部浓度从而增强药效,同时可减少药物透过真皮进入体循环从而减少副作用,具有良好的发展前景. 相似文献
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This paper describes the formation of a third liquid phase in a phase transfer catalytic system in the presence of benzyl alcohol and potassium hydroxide, where dodecane and tetraalkylammonium bromide serve as organic solvent and catalyst, respectively. In this kind of system, a symmetrical ether (dibenzyl ether) was synthesized from benzyl chloride and benzyl alcohol at 323 K. In particular, the investigation demonstrates that the observed reaction rate constant depends on the length of the alkyl group of the catalyst. Tetrabutylammonium bromide exhibits the highest catalytic activity among the catalysts explored. With respect to the reuse of the third liquid phase, the results confirm that there is no decrease in phase transfer catalytic activity in three consecutive runs. 相似文献
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纳米分子筛表现出许多独特的物理性质,如高外比表面积和丰富的表面硅羟基,具有独特的催化性能和对气体的分离能力。总结了近年来在纳米分子筛的合成、表征、性质及应用方面的最新研究进展。认为将纳米分子筛通过原位晶化技术组装到一定基质上,使其具有梯度分布的孔结构、合适的酸性和高的水热稳定性,将会成为今后发展的趋势。 相似文献
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《Ceramics International》2016,42(3):3820-3825
Environmentally benign procedure for synthesis symmetrical imidazolium based ionic liquids has been achieved. These Ionic liquids dissolved in water have been used as a reaction medium for synthesis of different morphologies of ZnO nanostructures like nanocoral, spherical and nanosheet by reflux method. The structural and optical properties of these ZnO particles were studied by using XRD, SEM and UV–visible. The characteristic results revealed that the anion and cation of ionic liquids effect on band gap and morphology of the zinc oxide species. The results show that the longer alkyl chain at positions 1 and 3 of imidazole ring ionic liquid cause the nanosheet morphology. 相似文献