纳米材料及其在高分子建筑材料中的应用

本文论述了纳米材料及其纳米材料的特性、纳米材料的制造方法和纳米材料在高分子 建筑材料中的应用。     

纳米材料在太阳电池中的应用

主要对太阳电池纳米材料研究进展进行了综述。简要介绍了半导体和多元化合物纳米材料．复合纳米材料。导电聚合物-纳米复合材料以及染料敏化纳米复合材料的在太阳电池中的应用以及这些纳米材料的国内外研究现状。     

纳米科技在建筑材料中的应用

介绍了纳米材料的特性 ,着重按纳米材料的功能对纳米科技在建筑材料的应用前景进行了阐述 ,展望了纳米材料和纳米技术的良好应用前景     

纳米材料毒性机制及其影响因素

纳米材料以其独特的物理化学性质被广泛应用到工农业和人们生活的各个领域,随着纳米材料的生产加工和使用,纳米材料可以经过大气循环、水循环、生物循环进入生态环境,进而侵染生物体,影响人类健康.因此,纳米材料的毒性问题日益受到人们的关注,而纳米材料毒性机制和影响因素是纳米材料毒性研究的热点问题之一.目前,氧化应激和炎症反应是解释纳米材料毒性的两种主要机制,此外,越来越多的研究表明自噬也是纳米材料毒性的一种潜在机制,并且自噬可能与氧化应激和炎症反应相互关联.另一方面,纳米材料的物理化学性质如尺寸、形状、表面修饰等对其毒性产生重要影响.本文首先概括了纳米颗粒进入环境及侵染生物体的方式,分析纳米材料引起生物和环境毒性的机制,最后对影响纳米材料毒性的因素进行深入探讨,以期为纳米毒理学研究提供帮助.     

纳米材料在混凝土中的应用研究现状与发展

在简要介绍了现代混凝土发展趋势和纳米材料的特性的基础上,综合评述了各种纳米材料在混凝土中研究历程和进展,以及纳米材料在特种混凝土中的应用情况,并提出了建议和展望。     

碳纳米材料应用于建筑防水涂料的研究进展

本文介绍了碳纳米材料的微观结构、制备技术和性能特点,总结了碳纳米材料应用于建筑防水涂料的研究成果,分析和探讨了碳纳米材料应用于建筑涂料所存在的问题及发展趋势。     

复合纳米材料对混凝土及水泥砂浆的性能影响

研究了加入不同比例复合纳米材料和掺30～40％四掺复合掺合料的胶砂和C40级混凝土的性能。对复配的C40级混凝土试块进行了氯离子和硫酸盐侵蚀试验、对复配净浆试块进行了扫描电镜（SEM）和差示扫描量热（DSC）测试。并讨论了复合纳米材料在混凝土中的不同加入方式。结果表明：相对于基准C40级混凝土。掺入复合掺合料和复合纳米材料配制的C40级混凝土的流动性和抗硫酸盐、氯离子侵蚀的能力均有所增强,其抗压强度提高约20％;复合纳米材料掺入减水剂用于混凝土的效果优于掺入复合掺合料用于混凝土。复合纳米材料掺入减水剂中可以很好地解决纳米材料易于团聚的问题,确定了复合纳米材料的掺入方式是将复合纳米材料掺入减水剂中,掺入量为减水剂质量的0．5-1．0％．     

七项纳米材料国家标准

2005年2月28日，国家质检总局和国家标准委联合发布了7项纳米材料国家标准这是世界上首次以国家标准形式发布的纳米材料标准。国家标准委主任李忠海在新闻发布会上的讲话中指出，7项纳米材料标准的发布和实施，将引导和规范我国的纳米材料市场秩序，促进纳米材料产业化的发展。7项标准将于2005年4月1日起实施。     

纳米材料及其前景展望

介绍了纳米材料的特性、结构、分类和应用领域 ,并对纳米材料进行了展望     

信息与文摘

新产品新技术纳米材料应用技术转化平台建成北京市建筑材料科学研究院承担的北京纳米材料应用技术转化平台近日初步建成。１９９８年 ,该院承担了北京市科委重点项目———“北京纳米材料应用技术转化平台的建设”。纳米材料是指物质粒径至少有一维在１～１００ｎｍ之间、具有特殊物理化学性能的材料。该院已经进行产业化的新技术有纳米材料改性建筑色浆、纳米材料改性高耐候性建筑涂料、纳米材料改性防水密封胶粘带以及中空玻璃密封胶条等。这些新产品已逐步投放市场 ,出现了供不应求的局面。北京纳米材料应用技术转化平台的建成 ,为发展北…     

超耐候建筑外墙涂料的研究

对提高建筑外墙乳胶涂料的耐候性进行了研究 ,并加入纳米二氧化钛作为涂料的部分取代颜填料 ,利用纳米粉体材料对紫外光的吸收特性 ,研究其添加用量对乳胶涂料性能的影响 ,特别是对耐候性能的影响。使加入纳米二氧化钛的乳胶漆的耐人工老化时间提高到 10 0 0小时以上。     

碳化硅粉体表面改性研究进展

随着纳米技术制备新型陶瓷材料研究的不断深入,对纳米级粉体的使用日益广泛。但由于纳米粉体的表面活性很大,很容易团聚在一起。通过表面改性可以使粉体达到稳定分散,因而这一技术也受到越来越广泛的关注。本文主要对碳化硅纳米粉体表面改性方法及表面改性对粉体性能影响进行了介绍,并且对碳化硅粉体的应用前景进行了展望。     

纳米氧化铝粉体的制备方法及应用

纳米氧化铝粉体除了具有纳米效应,在光、电、力学和化学反应等许多方面也表现出一系列的优异性能,已成为一种应用广泛的纳米材料。本文综述了纳米氧化铝粉体材料的各种制备工艺及方法的优缺点,并对近年来的应用进展进行了阐述。     

Fe~(3+)/N-TiO_2填料日光催化处理微污染源水

采用溶胶凝胶法制备了铁、氮共掺杂二氧化钛(Fe3+/N-TiO2)粉末,通过浸渍涂膜法将其负载到聚丙烯(PP)生物填料上,并考察了日光激发改性TiO2对微污染源水的处理效果.结果表明,铁、氮的掺杂大大提高了TiO2对太阳光的利用效率,当流量为0.12 m3/h时,负载型Fe3+/N-TiO3填料对CODMn和NH+4-N的去除率分别达到59%和75%.采用扫描电镜观察运行前后填料的表面状况,发现Fe3+/N-TiO2膜的保持程度较好,运行3个月后未发生明显脱落;膜表面生长了类似微生物的物质,可以推测在PP填料表面微生物与二氧化钛形成了功能分区,可以同时进行光化学氧化和生物降解作用.     

Novel, bio-based, photoactive arsenic sorbent: TiO2-impregnated chitosan bead

A novel sorbent for arsenic, TiO₂-impregnated chitosan bead (TICB), has been synthesized and successfully tested. Kinetic plots, pH dependence, isotherm data, and bead morphology are reported. Equilibrium is achieved after 185 h in batch experiments with exposure to UV light. The TICB system performs similarly to the mass equivalent of neat TiO₂ nanopowder. The point of zero charge (pzc) for TICB was determined to be 7.25, and as with other TiO₂-based arsenic removal technologies, the optimal pH range for sorption is below this pH_pzc. Without exposure to UV light, TICB removes 2198 μg As(III)/g TICB and 2050 μg As(V)/g TICB. With exposure to UV light, TICB achieves photo-oxidation of As(III) to As(V), the less toxic and more easily sequestered arsenic form. UV irradiation also results in enhanced arsenic removal, reaching sorption capacities of 6400 μg As/g TICB and 4925 μg As/g TICB, where arsenic is initially added as As(III) and As(V), respectively. Because the TICB system obviates filtration post-treatment, TICB is superior to TiO₂ nanopowder from the perspective of implementation for decentralized water treatment.     

Synthesis and characterisation of multi-walled carbon nanotubes (MWCNTs)

ABSTRACT

Carbon nanotubes are one of the major research areas in the field of nanotechnology, due to its mechanical and electro-conductive properties in the field of engineering and medical sciences. This paper focuses on preparation of multi-walled carbon nanotubes (MWCNTs) for the mass production using thermal catalytic chemical vapour deposition method. The synthesis of MWCNTs was made by breakdown of acetylene (C₂H₂) gas and Fe/MgO acting as catalyst. The surface morphology and structure of MWCNTs were characterised by scanning electron microscopy (SEM). Also phase identification and crystalline size of the nanopowder were determined by XRD. The particle size of MWCNTs was verified by SEM analysis and it was in the range of 20–30?nm and elemental analysis was carried out through energy dispersive analysis X-ray. Furthermore, thermal decomposition of the material property was studied by thermogravimetric analysis.     

Modification of ceramic microfilters with colloidal zirconia to promote the adsorption of viruses from water

The purpose of this study was to test the feasibility of modifying commercial microporous ceramic bacteria filters to promote adsorption of viruses. The internal surface of the filter medium was coated with ZrO(2) nanopowder via dip-coating and heat-treatment in order to impart a filter surface charge opposite to that of the target viruses. Streaming potential measurements revealed a shift in the isoelectric point from pH <3 to between pH 5.5 and 9, respectively. While the base filter elements generally exhibited only 75% retention with respect to MS2 bacteriophages, the modified elements achieved a 7log removal (99.99999%) of these virus-like particles. The coating process also increased the specific surface area of the filters from approximately 2m(2)/g to between 12.5 and 25.5m(2)/g, thereby also potentially increasing their adsorption capacity. The results demonstrate that, given more development effort, the chosen manufacturing process has the potential to yield effective virus filters with throughputs superior to those of current virus filtration techniques.     

Enhanced absorption of fire induced heat radiation in liquid droplets

The influence of additives on the interaction between radiation from fires and single water droplets has been investigated in detail. A literature study was performed on available information of radiation spectra from different types of fires. Based on this, four reference spectra were proposed that cover most of the different types of radiation that can be expected from fires. These reference spectra were used to compare the effect of different water additives and droplets sizes.Using Mie-theory it was found that increased atomization, down to a diameter limit of 1–10 μm, gives a better volumetric absorption efficiency. Decreasing the diameter further does not lead to improved volumetric absorption since the Rayleigh (small droplet) limit is reached, where the volumetric absorption is independent of diameter.Different additives were investigated with respect to increased absorption in the droplets. It was found, however, that it is not trivial to find non-flammable and non-toxic additives that give a significant improvement in absorption. Carbonated water was a potential candidate but the increased absorption was limited to a very weak band centered at 2300 cm⁻¹. Since this coincides with the strong CO₂ emission band an effect could be seen when carbonated water interacted with radiation from clean flames. The maximum increase in volumetric absorption for carbonated water was 4%, occurring for a droplet diameter of 10 μm. Other additives gave better effects but they were either combustible (carbon nanopowder) and/or toxic to some degree.     

The effects of changing water flow velocity on the formation of biofilms and water quality in pilot distribution system consisting of copper or polyethylene pipes

We studied the effects of flow velocity on the formation of biofilms and the concentration of bacteria in water in copper and plastic (polyethylene, PE) pipes. The formation of biofilms increased with the flow velocity of water. The increase in microbial numbers and contents of ATP was clearer in the PE pipes than in the copper pipes. This was also seen as increased consumption of microbial nutrients in the pipeline system. This indicates that the mass transfer of nutrients is in major role in the growth of biofilms. However, the increased biomass of biofilms did not affect microbial numbers in the water. Rapid changes in water flow rate resuspended biofilms and sediments which increased the concentrations of bacteria and copper in water. The disturbance caused by the changing water flow was also seen as an increase in the particle counts and water turbidity recorded with online instrumentation.     

Alteration of arsenopyrite in soils under different vegetation covers

The weathering of arsenopyrite (FeAsS) has been monitored in soils using an in situ experimental approach. Arsenopyrite in nylon experimental bags was placed in individual horizons in soils in spruce (litter, horizons A, B, and C), beech (litter, horizons A, B, and C) and unforested (horizons A, B, and C) areas and left in contact with the soil for a period of 1 year. The individual areas on the ridge of the Krušné hory Mts., Czech Republic, had the same lithology, climatic and environmental conditions. Scorodite (FeAsO₄·2H₂O) was identified as a principal secondary mineral of arsenic (As) formed directly on the surface of the arsenopyrite. Scorodite was formed in all the areas in all soil horizons. The amount of scorodite formed decreased in the series beech, spruce and unforested areas. In forested areas, there was a larger amount of scorodite on arsenopyrites exposed in organic horizons (litter, A horizon). The greater rate of arsenopyrite alteration in organic horizons in the beech stand compared to spruce stand is probably a result of faster mineralization of organic material with resulting production of nitrate and better seepage conditions of soil in this area. Speciation of As determined using the sequential extraction technique demonstrated that As was bonded in the soils primarily in the residual fractions prior to the experiment. The As content in the mobile fractions increased in the organic horizon in the forested areas after the experiments.