Nano-tribological study on a super-hydrophobic film formed on rough aluminium substrates

A novel super-hydrophobic stearic acid (STA) film with a water contact angle of 166^o was prepared by chemical adsorption on aluminum wafer coated with polyethyleneimine (PEI) film. The micro-tribological behavior of the super-hydrophobic STA monolayer was compared with that of the polished and PEI-coated Al surfaces. The effect of relative humidity on the adhesion and friction was investigated as well. It was found that the STA monolayer showed decreased friction, while the adhesive force was greatly decreased by increasing the surface roughness of the Al wafer to reduce the contact area between the atomic force microscope (AFM) tip and the sample surface to be tested. Thus the friction and adhesion of the Al wafer was effectively decreased by generating the STA monolayer, which indicated that it could be feasible and rational to prepare a surface with good adhesion resistance and lubricity by properly controlling the surface morphology and the chemical composition. Both the adhesion and friction decreased as the relative humidity was lowered from 65% to 10%, though the decrease extent became insignificant for the STA monolayer. The project supported by the National Natural Science Foundation of China (50375151, 50323007, 10225209) and the Chinese Academy of Sciences (KJCX-SW-L2)     

步进扫描时间分辨光谱及其在太阳电池光电导上的应用

建立傅里叶变换步进扫描时间分辨光电导光谱，并研究太阳电池中与转换效率密切相关的少数载流子寿命.实验选取三种典型的硅太阳电池(单晶硅样品1、多晶硅样品2和多晶硅样品3 )，发现其瞬态光电导的上升和衰退曲线可以分别用两个简单的指数函数描述.由于有复合中心的参与，复合过程中少数载流子的寿命比产生过程中的寿命短.为验证实验结果的可靠性，采用了提取样品少数载流子的体寿命和计算其有效扩散长度两种方法.通过与太阳电池暗伏安特性和负载特性研究相结合，进一步分析和讨论了少数载流子寿命与短路电流、开路电压和转换效率的关系.同时探讨了步进扫描时间分辨光谱实验的其他用途. 关键词： 步进扫描 时间分辨 硅太阳电池 瞬态光电导     

TiN和Ti1-xSixNy薄膜的微观结构分析

使用x射线衍射(XRD)、x射线光电子谱(XPS)、高分辨透射电子显微镜(HRTEM)和原子力显微镜(AFM)多种观测手段分析了TiN薄膜和Ti1-xSixNy纳米复合薄膜的微观结构.实验分析证明Ti1-xSixNy薄膜是由直径为3-5nm的纳米晶TiN和非晶Si3N4相构成,并且Ti1-xSixNy薄膜的表面粗糙度小于相同条件下制备的TiN薄膜,在Ti1-xSixNy薄膜体系的自由能中引入界面能的概念,在此基础上分析了体系中TiN晶粒的取向问题.     

走近纳米科技

 纳米科技于20世纪70年代兴起,进入21世纪越来越被大家耳熟。纳米科技在促进科技进步,提高社会文明程度,改善人类生存质量,更新对物质世界的认知及观念上扮演了举足轻重的角色。纳米是长度单位。一纳米为一米的十亿分之一,如果你的拇指指甲盖宽14毫米,这个比例就相当于拇指指甲盖宽度与地球直径间的比例。纳米科技所接触、研究、开发的是100纳米～0.1纳米范围内物质的性质和应用。一个分子或一个原子大小的数量级大致在10纳米。因此,纳米科技也可以说是在分子水平上观察、分析、研究物质的物理、化学性质并加以开发利用。     

硅光电二极管激光损伤阈值随激光脉宽的变化

 对飞秒激光辐照下硅光电二极管损伤阈值进行了实验测量，对从1s到60fs不同脉宽激光辐照下硅光电二极管损伤阈值进行了讨论。实验数据表明，在1s到10ns脉宽范围内损伤所需能量密度近似而非严格地与脉宽的平方根成正比。信号分析表明硅光电二极管的损伤主要由热效应造成，而60fs激光辐照下的损伤阈值为0.1J/cm2，明显偏离普通温度分布预言的趋势。     

纳米KMn8O16粉体的室温固相合成与表征

室温或近室温固相反应要求绿色化、清洁化[1,2]。我们以KMnO4和MnCl2·4H2O为原料,用室温固相氧化还原反应制备氧化锰粉体时,得到了一种对H2O2分解具有较高催化活性的纳米KMn8O16粉体,用XRD、SEM、IR等技术对其进行了表征,发现研磨时间对粉体性能有显著影响。1　实验部分1 1　粉体的制备按摩尔比(2∶3)准确称取一定量的分析纯KMnO4和MnCl2·4H2O,分别置于玛瑙研钵中充分研细,再混合研磨,固相反应立即发生,体系颜色逐渐加深,并有刺激性气体产生,充分研磨后70℃恒温12h,固相产物依次经水洗至中性、醇洗、抽滤,真空干燥得黑色粉…     

Self-assembly of Carboxyl Functionalized Polystyrene Nanospheres into Close-packed Monolayers via Chemical Adsorption

The polyacrylic acid functionalized polystyrene nanospheres were synthesized and self-assembled into irregular, densely packed monolayers in non-aqueous media. The polymer nanoparticles were chemically adhered to substrates. The morphologies of the resulting films were investigated. The impact of the volume fraction of alcohol in the mixed solvents on the particle adsorption and fabrication of nanosphere assembled films was examined.     

Studies on Synthesis and properties of Mg-Al-nitrate Layered Ouble Hydroxides

A positive Mg-Al-nitrate layered double hydroxides(LDHs) has been synthesized using a non-steady coprecipitation method.The shape.size,chemical composition,electrical property and anion exchange property of the positve nanoparticle were studied by SEM,XRD,FTIR,chemical analysis,spectroanalysis and meaxsuring of electrophoretic mobilities.Preliminary results show the positive nanoparticle is a promising precursor of polymer/LDHs nanocomposite.     

ZrO2纳米粉等离子喷涂层组织与性能

用纳米结构粉末做喂料进行喷涂，缩短了颗粒熔化时间，在有限的飞行时间内，颗粒熔化效果更好，从而制备的涂层孔隙率更小，表面更平整。用ZrO2纳米结构喂料制备了等离子喷涂层，研究了功率、粒度、氧化钇含量等工艺参数条件下涂层的微观组织、孔隙率、相组成及抗热震性能。经X衍射分析表明，原始粉末由m-ZrO2,t-ZrO2,c-ZrO2构成，单斜相的含量为11％，主要由四方相和立方相构成。