纳米科技·纳米经济·纳米会计

纳米科技将在新世纪引发一场新的工业革命。鉴此 ,本文首先介绍了纳米科技的概念及其广阔的应用领域 ;接着论述了国内外纳米科技带动纳米经济发展的概况及美好前景。最后提出了应运而生的纳米会计的基本框架和主要内容。     

纳米科技:于细微处见神奇

螃蟹为什么会横着行走?蜜蜂怎样准确辨明方向,回到自己的蜂巢?荷叶如何能够洁身自好,滴水不沾?事实上,这些生物都是纳米科技界的高手:螃蟹、蜜蜂、海龟等生物体内存在着纳米尺寸的磁性颗粒,该颗粒对于生物的定位与运动行为具有重要意义,如螃蟹的内耳中有对地磁非常敏感的纳米磁     

施用纳米肥料对小麦微结构和营养品质的影响

为了研究施用纳米肥料399植物生长剂后小麦籽粒微结构和营养品质的变化,通过扫描电子显微镜(SEM)观察比较了施用和未施用399植物生长剂的小麦籽粒的外部形貌和截面特征.通过观察发现,399植物生长剂对表皮细胞、糊粉层及胚乳的生长都有促进作用.对小麦蛋白质、脂肪、粗纤维和重金属的质量分数进行了检测分析.结果表明,施用399植物生长剂的小麦蛋白质质量分数提高了8%以上,粗脂肪质量分数提高了5%以上;粗纤维、铅的质量分数与399植物生长剂的施用没有正相关性.     

纳米晶材料的制备,结构性能及其进展

纳米晶材料是近年来发展起来的一种新型材料，其单个晶粒尺寸为纳米级，构成了一种与晶态和非晶态均不相同的新型结构，由此产生了许多独特的性能。本文综述了纳米晶材料的研究动态、介绍了纳米晶材料的制备、结构表征和性能研究的进展及纳米晶材料的发展动物。     

纳米有序结构制备技术现状

随着对纳米材料需求的不断增长，人们对如何制备纳米有序结构的技术产生了极大的兴趣。主要概述了近期来制备纳米有序结构的一些基本方法例如膜板合成法、自组织方法、欠电位沉积法、掠角沉积法等，并在此基础上简要的介绍了一些相关的概念原理和应用。     

纳米科学技术与纳米材料概述

介绍了纳米科学技术、纳米材料的概况及纳米材料的结构、特性、制备方法和应用前景。     

金属纳米粒子的制备与应用

金属纳米粒子独特的结构决定了其独特的性能。评述了金属纳米粒子的制备、改性及应用的研究进展。     

纳米食品加工技术及安全性评价

纳米技术在食品领域的应用产生了纳米食品.主要综述了在食品加工中应用的相关纳米技术、纳米食品的安全性风险与安全性评价等方面的最新进展.     

聚丙烯/无机纳米复合材料的研究进展

综述了聚丙烯／无机纳米复合材料的性能及应用,并介绍了纳米ＴｉＯ２改性聚丙烯（ＰＰ）的机理。     

金属纳米粒子的制备与应用

金属纳米粒子独特的结构决定了其独特的性能。评定了金属纳米粒子的制备、改性及应用的研究进展。     

ZnO和CuO混合纳米颗粒在添加FCC粗颗粒的 流态化及聚团碰撞与破碎过程研究

研究混合纳米Zn O和Cu O颗粒添加3种不同粒径FCC粗颗粒(催化裂化催化剂)的流化行为,用高速摄像机观察流化现象并对聚团碰撞与破碎过程、聚团成分进行分析。结果表明,添加FCC粗颗粒可显著改善纳米颗粒的流化性能,FCC3对纳米颗粒流化性能的改善效果比FCC1或FCC2更明显;且随着FCC粗颗粒添加量的增加,纳米颗粒流化行为的改善效果越好,体系的混合均匀程度是影响混合纳米Zn O和Cu O流化性能的重要因素。     

混合纳米SiO2和纳米TiO2颗粒在 添加FCC的流态化研究

混合纳米颗粒作为催化剂已经被应用于各工业领域。然而由于纳米颗粒的流态化性能较差,需要研究改善混合纳米颗粒流态化性能的方法。现阶段,国内外的研究大多集中在对单一纳米颗粒添加组分的流态化与混合纳米颗粒在外力场中的流态化,对混合颗粒添加组分的流态化未见报道。试验研究了纳米SiO2和纳米TiO2的混合组分在添加3种不同的FCC颗粒的流态化,为研究混合组分流化床中颗粒的碰撞、团聚和破碎机制提供实验基础。研究发现单纯的混合纳米颗粒难以流态化,添加FCC颗粒后其流态化性能有所提高,FCC颗粒对混合纳米颗粒流化性能的改善能力与其粒径和添加量有关。另外FCC2和FCC3颗粒对混合纳米颗粒的流化性能改善能力优于FCC1颗粒。相同添加量下,纯的SiO2流化性能最好,其余按由好到坏的顺序分别是w(SiO2):w(TiO2)=7:3,w(SiO2):w(TiO2)=5:5,w(SiO2):w(TiO2)=3:7以及纯的TiO2纳米颗粒。     

Experimental Study on Enhancement of Bubble Absorption of Gaseous CO2 with Nanofluids in Ammonia

纳米颗粒强化氨水鼓泡吸收CO₂实验研究

方立军,刘洪锟,边岩,刘玉东,杨亚利

（华北电力大学（保定） 能源动力与机械工程学院）

研究目的：

探究纳米颗粒对鼓泡塔氨法吸收二氧化碳的强化作用

研究方法：

（1）试剂：氨水,质量分数为25%-28%,天津化工有限公司生产;二氧化碳气体,纯度为99.99%,氮气,99.99%,保定北方特种气体有限公司生产;纳米颗粒（SiO₂、TiO₂、CuO）,由南京埃普瑞纳米材料有限公司提供。

（2）本文纳米流体的制备方法采用的是“两步法”,首先用天平准确称取所需的纳米TiO₂、CuO、SiO₂,量取所需要的蒸馏水,然后通过机械分散20分钟,加入一定量的氨水,继续机械分散10分钟制备为不同质量分数的纳米流体,纳米流体的分散稳定性良好。

（3）实验系统：纳米颗粒强化氨水鼓泡吸收CO₂实验系统如图所示,主要包括鼓泡吸收塔、烟气配送系统、尾气测量处理系统。

实验步骤：

（1）实验前先计算出配制纳米流体所需的纳米颗粒、氨水、蒸馏水的量,用电子秤称出纳米颗粒的质量,将其加入到蒸馏水中,机械搅拌20min,加入一定量的氨水,继续机械分散10分钟制备为不同质量分数的纳米流体;

（2）打开分析仪预热30min,开通N2对整个系统进行吹扫,待CO2烟气分析仪示数降为0时。按照比例将氮气与二氧化碳充入混合瓶,混合均匀后通入分析仪,待示数达到预设值且稳定;

（3）将配制好的纳米流体加入到反应塔内,开始计数,每5s计数一次,待示数不再降低,停止计数。

为减少偶然误差带来的影响,每组实验均进行5次,然后取其平均值。为减少氨水浓度对本实验的影响,每次实验都要测量配制好的溶液的pH值,保证初始溶液具有相同pH值。

结果：

（1）纳米颗粒种类和固含量对增强因子的影响

对氨水质量分数为1%,CuO、TiO₂、SiO₂颗粒添加量分别为1g/L、2g/L、3g/L、4g/L、5g/L的纳米流体进行鼓泡吸收实验,增强因子如图所示：

增强因子与纳米颗粒种类的关系

从图中可以看到只有添加TiO₂这一种纳米颗粒时,其增强因子一直大于1;添加SiO₂ 纳米颗粒,只有在1g/L、2g/L时,增强因子略大于1,其他添加量则小于1;添加CuO 纳米颗粒,其增强因子始终在1左右徘徊,没有出现出明显的增强或抑制作用。

（2） 氨水浓度对增强因子的影响

从图中可以看出,不同氨水浓度下,增强因子的变化趋势随固含量的增加先升高后降低。但是,它们的最佳固含量不同,随着氨水浓度的升高,最佳固含量降低。

（3） 纳米颗粒种类对脱除率的影响

从图中可以看出,TiO2纳米流体的吸收率要大于空白溶液,CuO纳米流体的吸收率和空白溶液相同,而SiO2纳米流体的吸收率小于空白溶液。

（4）纳米颗粒添加量对脱除率的影响

从图中可以看出,脱除率随纳米颗粒添加量的增加先增高后降低,且脱除率一直大于空白溶液实验,在纳米颗粒添加量为3.0g/L时脱除率达到最大值。

结论：

（1）纳米颗粒的添加对于部分有化学反应气液传质过程具有强化作用,其强化作用与纳米颗粒和溶剂的性质有关;

（2）对气体溶质具有选择吸附性、增溶剂性的纳米颗粒可对有化学反应的气液传质过程有强化作用。其强化作用随着纳米颗粒添加量的增加先增大后减小,即纳米TiO2的含量对强化氨水捕集CO₂存在一个最佳固含量;

（3）对气体溶质没有吸附性但具有亲溶剂性的纳米颗粒可对有化学反应的气液传质过程有抑制作用。其抑制作用随着纳米颗粒添加量的增加而逐渐增强;

（4）纳米颗粒强化有化学反应的气液传质过程的机理可总结为,纳米颗粒在布朗运动的作用下会使吸收工质内部形成微对流,从而使分子扩散系数增大。纳米颗粒对气体溶质的吸附性,使传质边界层内气相溶质浓度降低,传质边界层内的浓度梯度增大,传质推动力增加,气体吸收得到强化。

关键词：纳米颗粒;鼓泡塔吸收;氨水;CO₂捕集;强化吸收

     

Assessment of pH-responsive nanoparticles performance on laboratory column flotation cell applying a real ore feed

Nanoparticles(NPs) can promote the column flotation process in mining industry. Nanoparticles' effects on column flotation process(copper recovery, grade and flotation rate constant) are assessed in Sarcheshmeh Copper Complex, Iran, through response surface methodology(RSM) optimization technique. The c-Al_2O_3, a-Fe_2O_3, SiO_2, and TiO_2 nanoparticles are selected for these experiments. A flotation rate constant is chosen as a response to assess the effect of nanoparticles on flotation in its kinetic sense.The process p H and nanoparticle dosage are selected as the influential parameters. Results obtained from RSM indicated that the maximum percentage of Cu recovery and grade is obtained at p H of 12 and nanoparticle dosage of 6 kg/t, through a-Fe_2O_3 and c-Al_2O_3 nanoparticles, respectively. Applying nanoparticles in particular c-Al_2O_3 and a-Fe_2O_3 increases the Cu recovery by 8–10% together with the grade by 3–6% in a significant manner. It is revealed that nanoparticles could effectively be applied in enhancing the flotation performance.     

Optical properties and cooling performance analyses of single-layer radiative cooling coating with mixture of TiO2 particles and SiO2 particles

Radiative cooling can achieve cooling effect without consuming any energy by delivering energy into outer space(3K) through"atmospheric window"(8–13 μm). Conventional radiative cooling coating with multi-layer structure was severely restricted during application due to its complex preparation process and high cost. In this study, a single-layer radiative cooling coating with mixture of TiO_2 particles and SiO_2 particles was proposed. The algorithm for calculating the radiative properties of the multi-particle system was developed. Monte Carlo ray-tracing method combined with that algorithm was used to solve the radiative transfer equation(RTE) of the single-layer radiative cooling coating with mixture of TiO_2 particles and SiO_2 particles.The effects of particle diameter, volume fraction and coating thickness on radiative cooling performance were analyzed to obtain the best radiative cooling performance. The numerical results indicated that the average reflectivity of the single-layer radiative cooling coating with mixture of TiO_2 particles and SiO_2 particles in the solar spectrum can reach 95.6%, while and the average emissivity in the "atmospheric window" spectrum can reach 94.9% without additional silver-reflectance layer. The average reflectivity in the solar spectrum and average emissivity in the "atmospheric window" spectrum of the single-layer radiative cooling coating with mixture of TiO_2 particles and SiO_2 particles can increase 4.6% and 4.8% compared to the double-layer radiative cooling coating. This numerical research results can provide a theoretical guidance for design and optimization of single-layer radiative cooling coatings containing mixed nanoparticles.     

Innovative pre-concentration technology for recovering ultrafine ilmenite using superconducting high gradient magnetic separator

To achieve the utilization of the abandoned ultrafine ilmenite (−20 μm) produced in the titanium magnetite processing plant in Panzhihua, the superconducting high-gradient magnetic separation (SMS) technology was proposed in this study. After optimizing the conditions of magnetic intensity, feeding and pulsation, an SMS concentrate with TiO₂ grade of 16.03% and TiO₂ recovery of 66.39% was obtained through one roughing–one cleaning pre-concentration flowsheet. The specific magnetic force and magnetic force were calculated and analysed to illustrate the pre-concentration mechanism, and the results revealed that the combination of high magnetic field and strong pulsating resulted in the effective pre-concentration of the ultrafine ilmenite in the SMS process. In addition, the magnetic force analysis indicated that the high magnetic intensity and high magnetic gradient are the key factors of the SMS technology. Furthermore, the EDS-Mapping detection certified that the ultrafine ilmenite was concentrated from the gangue minerals using SMS technology.     

Improved visible transparency of SIO<Subscript>2</Subscript>/ZNO:AL /CEO<Subscript>2</Subscript>-TIO<Subscript>2</Subscript>/SIO<Subscript>2</Subscript> multilayer films with high UV absorption and infrared reflection rate

New visible transparent, UV absorption, and high infrared reflection properties have been realized by depositing multilayer SiO₂/ZnO: Al/CeO₂-TiO₂/SiO₂ films onto glass substrates at low temperature by radio frequency magnetron sputtering. Optimum thickness of SiO₂, ZnO: Al (ZAO) and CeO₂-TiO₂ (CTO) films were designed with the aid of thin film design software. The degree of antireflection can be controlled by adjusting the thickness and refractive index. The outer SiO₂ film can diminish the interference coloring and increase the transparency; the inner SiO₂ film improves the adhesion of the coating on the glass substrate and prevents Ca²⁺, Na⁺ in the glass substrate from entering the ZAO film. The average transmittance in the visible light range increases by nearly 18%-20%, as compared to double layer ZAO/CTO films. And the films display high infrared reflection rate of above 75% in the wavelength range of 10-25 μm and good UV absorption (> 98%) properties. These systems are easy to produce on a large scale at low cost and exhibit high mechanical and chemical durability. The triple functional films with high UV absorption, antireflective and high infrared reflection rate will adapt to application in flat panel display and architectural coating glass, automotive glass, with diminishing light pollution as well as decreasing eye fatigue and increasing comfort.     

Preparation and characterization of natural rubber/silica nanocomposites using rule of similarity in latex

Rule of similarity and latex compounding techniques were combined for the first time to prepare natural rubber/nanosilica (NR/SiO₂) nanocomposite with core-shell nanosilica-poly (methyl methacrylate) (SiO₂-PMMA) particles and PMMA-modified natural rubber matrix (NR-PMMA). The microstructure of SiO₂ and nanocomposites with different SiO₂ contents was characterized by fourier transform infrared spectroscopy (FTIR); the morphology of nanocomposites was investigated with scanning electron microscopy (SEM); the tensile strength was characterized by tensile testing machine and the thermal stability of composites was studied by thermal gravimetric analysis. Results showed that PMMA chains have successfully grafted onto the surface of SiO₂, and the core-shell SiO₂-PMMA nanoparticles and NR-PMMA latex have been perfectly incorporated. SiO₂-PMMA nanoparticles are evenly distributed over the NR matrix with an average size in the range of 60–100 nm at the low content (SiO₂≤ 3 wt%), while aggregations are apparently observed when 5 wt% SiO₂ is loaded. In addition, NR/SiO₂ composities possess a considerable improvement in ageing resistance compared with the pure NR. The tensile strength of composite increases from 6.99 to 12.72 MPa, reaching the highest value at a 0.5 wt% SiO₂ loading, and then the figure decreases gradually because of the aggregation of SiO₂ nanoparticles. It is anticipated that the reported process is to provide a simple and economic way for preparing NR composites.     

Preparation of Al2O3-SiO2-TiO2-ZrO2 Composite Ceramic Membranes by Sol-Gel Method

Al2O3-SiO2- TiO2-ZrO2 supported membranes were prepared by Sol-Gel method. These composite ceramic membranes are level, even and no macro crack. There exist several crystalline phases such as Al2O3, TiO2 ( anatase ), Al2 SiO5 , and ZrO2 in these membranes. Changing the molar ratio of Al:Si: Ti : Zr ,the kinds and content of crystal phases of composite membranes could be different, which may lend to a variety of microstructure of membranes. The surface nanoscale topography and microstructure of membranes were investigated by XRD, SEM, AFM, EPMA. The effects of additives and heat treatments on the surface nanoscale topography and microstracture of composite ceramic membranes were also analyzed.     

Memory effect up to room-temperature in Ni/Ni2P core-shell structured nanoparticles

Memory effect has been studied in the system using magnetic nanoparticles with Ni nanocore encapsulated by non-magnetic and oxidation-resistant Ni2P nanoshell acquired through surface-phosphatizing Ni nanoparticles. The self-assembled array with interparticle spacing of about 6 nm shows memory effect up to 200 K below its average blocking temperature of 260 K. And reducing the interparticle spacing of the self-assembled array via annealing can further enlarge the temperature range of memory effect up to room-temperature. The memory effect can be understood based on the thermal relaxation theory of single-domain magnetic nanoparticles. Furthermore, the read-write magnetic coding is realized based on the temperature changes, using the memory effect up to room-temperature, which may be useful for future memory devices.