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采用相转化纺丝／烧结技术制备Al2O3多孔中空纤维膜,并以此为载体,通过晶种法考察不同晶种诱导条件制备TS-1复合中空纤维膜,并采用扫描电子显微镜、气体渗透性能测试装置等设备对所制备的TS-1复合中空纤维膜进行微观结构及渗透性能的表征。结果表明,晶种法制备的TS-1复合中空纤维膜的N2渗透速率较小,并且表面平整无缺陷,因此该方法适合制备性能优良的TS-1复合中空纤维膜。 相似文献
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采用复合乳液聚合方法制备了具有核壳结构的双烯／苯乙烯的核壳粒子，考察了乳化剂和单体加入方式及配比等因素对核壳粒子的影响。结果表明，通过控制反应条件，可以合成符合透明性要求，具有增韧性能的核壳粒子。 相似文献
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为制备性能优异的氧化铝-氧化锆纤维,获得相对稳定的氧化铝-氧化锆复合胶体至关重要。以氧氯化锆、醋酸锆、铝粉、盐酸为主要原料,聚乙烯醇作纺丝助剂,采用溶胶-凝胶法,制备氧化铝-氧化锆复合胶体,并用Zetasizer Nano Zs90纳米粒度分析仪、AR 1500EX流变仪等对其稳定性进行分析研究。结果表明:胶粒粒径集中分布在4nm~30nm,p H为3,且储能模量G'高于耗能模量G',两个模量几乎都与震荡频率相互独立时,胶体才不太可能在陈化过程中发生沉降;当胶体温度在25~30℃、含水率在45.7%~48.3%、剪切速率大于500 1/s时,胶体才能稳定的牵伸成纤。 相似文献
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国家自然科学基金对纳米材料的资助领域分析——基于共词网络法 总被引：1，自引：0，他引：1
通过对国家自然科学基金2000—2010年纳米材料资助项目的关键词进行分析,利用pajek软件对关键词绘制网络图谱,分析得出自然基金对纳米材料资助的主要领域归为3类,即纳米材料的制备、合成、应用、性能及纳米结构;各种纳米材料的研究如碳纳米管、各种聚合物、纳米晶、纳米粒子、纳米半导体、纳米复合材料等;纳米材料的组装、自组装、特异效应的研究。这些是自然基金对纳米材料资助的主要领域,也是我国纳米材料的研究热点。建议加强投入对纳米材料资助较弱的研究方向,如纳米陶瓷材料、纳米材料的形貌控制和缺陷控制等。 相似文献
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壳聚糖三维材料的制备及其应用研究进展 总被引：1，自引：0，他引：1
在生物材料的研究领域中,有关壳聚糖材料的制备与应用研究越来越受到重视,由于壳聚糖特殊的结构与性能导致壳聚糖三维材料的制备极其困难。本文着重介绍近年来壳聚糖三维材料制备研究的进展,重点是为三维壳聚糖无机复合材料、三维壳聚糖磁性功能材料、三维壳聚糖增强材料、三维壳聚糖仿生材料以及三维壳聚糖组织工程支架材料的研究进展及各材料的性能与应用方向;展望了壳聚糖三维材料的发展前景,特别是提高壳聚糖三维材料的力学性能以及在人体内环境下力学性能的耐衰减能力,在生物可降解骨折内固定材料与生物可降解骨组织工程的应用上起着决定作用,将是未来几年壳聚糖三维材料研究的重点和突破口。 相似文献
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思政课教师的教学能力与其备课能力有密切关系。思政课教师的备课能力会影响到学生马克思主义信仰的坚定和马克思主义能力的培养。思政课教师要采取备学生、备自己、备教材、备教学、备平台的有效方式,以及采取个人备课、领导干部宣讲备课、专家讲解备课、集体备课、网络学习备课、不同院系与学校备课的形式,以提升自己的备课能力。 相似文献
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Ferromagnetic materials such as iron, cobalt, and nickel lose their strong magnetic properties when heated to a temperature above that called the Curie temperature, a temperature which is different for different materials. For all known ferromagnetic materials this temperature is always below that of the corresponding melting points of the materials and thus intrinsic ferromagnetic liquids are not known to exist. The term magnetic liquid (or ferrofluid) as used today does not refer to an intrinsic ferromagnetic liquid but to a stable colloidal suspension of small particles of a ferromagnetic material. 相似文献
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本论文围绕有机共扼大π体系这一主题,利用共价键、配位键及弱相互作用如氢键、π-π堆积、亲水-疏水作用设计了一系列自组装超分子结构,在具有光电转换性能的给受体系、配位聚合物、光驱动的分子机器、空心胶囊等几个方面开展了一系列研究工作。 相似文献
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Xue-Hua Ding Yong-Zheng Chang Chang-Jin Ou Jin-Yi Lin Ling-Hai Xie Wei Huang 《国家科学评论(英文版)》2020,7(12):1906
Halogen bonding is emerging as a significant driving force for supramolecular self-assembly and has aroused great interest during the last two decades. Among the various halogen-bonding donors, we take notice of the ability of 1,4-diiodotetrafluorobenzene (1,4-DITFB) to co-crystallize with diverse halogen-bonding acceptors in the range from neutral Lewis bases (nitrogen-containing compounds, N-oxides, chalcogenides, aromatic hydrocarbons and organometallic complexes) to anions (halide ions, thio/selenocyanate ions and tetrahedral oxyanions), leading to a great variety of supramolecular architectures such as discrete assemblies, 1D infinite chains and 2D/3D networks. Some of them act as promising functional materials (e.g. fluorescence, phosphorescence, optical waveguide, laser, non-linear optics, dielectric and magnetism) and soft materials (e.g. liquid crystal and supramolecular gel). Here we focus on the supramolecular structures of multicomponent complexes and their related physicochemical properties, highlight representative examples and show clearly the main directions that remain to be developed and improved in this area. From the point of view of crystal engineering and supramolecular chemistry, the complexes summarized here should give helpful information for further design and investigation of the elusive category of halogen-bonding supramolecular functional materials. 相似文献
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我们应该使学生成为教育活动的中心,预习能有效地增强学生学习的自主意识,预习是课堂上发挥学生主体作用的前提,预习是培养学生自学能力的关键。根据教材的特点,采用预习的多种方法,养成预习的习惯,提高预习的能力,逐步提高学生的自学能力。 相似文献
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Clinical analysis of acute viral infection in blood requires the separation of viral particles from blood cells, since the cytoplasmic enzyme inhibits the subsequent viral detection. To facilitate this procedure in settings without access to a centrifuge, we present a microfluidic device to continuously purify bionanoparticles from cells based on their different intrinsic movements on the microscale. In this device, a biological sample is layered on top of a physiological buffer, and both fluids are transported horizontally at the same flow rate in a straight channel under laminar flow. While the micron sized particles such as cells sediment to the bottom layer with a predictable terminal velocity, the nanoparticles move vertically by diffusion. As their vertical travel distances have a different dependence on time, the micro- and nanoparticles can preferentially reside in the bottom and top layers respectively after certain residence time, yielding purified viruses. We first performed numerical analysis to predicate the particle separation and then tested the theory using suspensions of synthetic particles and biological samples. The experimental results using dilute synthetic particles closely matched the numerical analysis of a two layer flow system containing different sized particles. Similar purification was achieved using diluted blood spiked with human immunodeficiency virus. However, viral purification in whole blood is compromised due to extensive bioparticle collisions. With the parallelization and automation potential offered by microfluidics, this device has the potential to function as an upstream sample preparation module to continuously provide cell depleted bio-nanoparticles for downstream analysis. 相似文献
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集体备课是一个集思广益的过程。教师之间开展集体备课对提高教学质量起着重要的作用。本文根据独立院校的教学实践出发,探讨大学英语教师如何开展科学、实用的集体备课活动。并以广西某独立学院大学英语教研室为例分析教师在集体备课中如何备教材、备学生及备教法,以为其他独立院校的教学实践提供一个参考。 相似文献