基于纳米修饰透射式光纤传感测试

基于金属纳米颗粒结构的光学特性,结合光纤传感技术,对金属纳米颗粒的光纤传感特性进行了研究.实验中采用种子溶液生长法合成了粒径在60～80 nm的星形纳米金颗粒,以此作为光纤传感敏感部分的修饰体,修饰到锥形光纤表面作为表面拉曼增强基底.最后选取了不同浓度的酒精溶液对其进行了透射谱和拉曼谱测试,结果表明金属纳米颗粒的激发谱对周围介质特性非常敏感,同时对基于金属纳米颗粒锥形SERS基底的拉曼谱存在非常高的增强.     

基于水凝胶聚合物波导传感器检测盐酸吖啶黄

多功能化是光纤化学传感器的重要发展方向。为实现该目标,首先通过激光诱导波导自形成技术制备了一种光纤–水凝胶聚合物波导–光纤传感结构,并在水凝胶聚合物波导探针中成功地掺杂了纳米金颗粒。在该结构中,波导与光纤同轴无缝相连,保证了探测光和信号光的高效利用。掺金后的聚合物波导具有丰富的光谱探测能力,利用该波导探针成功实现了对盐酸吖啶黄的吸收、荧光以及拉曼光谱的检测,扩大了波导传感器的应用范围。     

改性ZnSn(OH)6纳米颗粒的制备、表征及摩擦学性能研究

在共沸蒸馏ZnSn（OH）6-正丁醇体系的同时,加入硬脂酸制备了改性ZnSn（OH）6纳米颗粒。用TEM、FTIR、XRD和TG／DTA等对这种纳米颗粒的形貌和结构进行了表征,ZnSn（OH）6纳米颗粒的大小为50～80nm。并在四球机上考察了它的摩擦学性能,在低负荷下,具有良好的抗磨性能。     

岛状纳米多孔金制备及其SERS特性研究

表面增强拉曼散射（surface-enhanced Raman scattering,SERS）技术将纳米结构材料和拉曼光谱相结合,解决了传统拉曼散射技术灵敏度低的问题,为痕量物质检测提供了新的技术手段。高SERS活性基底材料是将拉曼光谱应用到痕量物质检测中的关键。采用磁控溅射技术结合脱合金工艺在硅片上制备出岛状纳米多孔金SERS基底,该基底的孔隙尺寸和金韧带宽度的比值远小于传统纳米多孔金,有效地增强了金韧带之间的电磁耦合效应,表现出更强的局域电磁场。该基底的检测极限可达约10-10 mol·L-1,且SERS光谱相对强度与浓度呈现出较好的线性关系,动态响应范围可达3个数量级。同时该基底结构均匀、性能稳定,制备工艺具有良好的可重复性。     

基于金纳米颗粒的化学电阻传感器检测苯类气体

为提高气体传感器对苯系物的选择性,文中通过Au-S键的自组装作用和滴铸法制备了4-甲氧基苄硫醇(MTT)修饰的金纳米颗粒(AuNPs)化学电阻传感器,用扫描电子显微镜(SEM)对其微观形貌进行了表征.设计了气体检测平台和数据采集系统,并对传感器的气敏性能进行了检测,结果显示:基于MTT功能化的AuNP s化学电阻传感器...     

热处理对金纳米颗粒活性衬底的影响

利用退火工艺对拉曼增强衬底进行热处理,得到粒径和密度不同的金纳米颗粒拉曼增强衬底,并且此工艺不引入杂质离子。通过用生物大分子龙胆紫作为探针分子,对金纳米颗粒表面的表面增强拉曼散射(SERS)和表面增强荧光(SEF)进行研究发现,拉曼和荧光强度存在相同的变化趋势。研究结果表明:热处理可以优化SERS和SEF增强效果,为高效率、低成本的基于SERS和SEF效应生物化学传感器件的研究提供参考。     

表面修饰氧化锌纳米颗粒的制备及其抗磨性能研究

为改善纳米颗粒在润滑油中的分散稳定性,以硬脂酸锌为单源前驱体,成功制备出硬脂酸修饰的氧化锌纳米颗粒,用透射电子显微镜、X-射线粉末衍射仪、红外光谱仪等仪器对其进行结构表征,并在四球摩擦试验机上测试其抗磨性能。结果表明:所制备的硬脂酸修饰的ZnO纳米颗粒大小均匀,表面修饰层与纳米颗粒表面之间发生化学键合作用;硬脂酸修饰的ZnO纳米颗粒在非极性有机溶剂和润滑油中均具有良好的分散性,其作为润滑油添加剂具有良好的抗磨能力。     

Ar离子轰击对金纳米颗粒团簇的影响

利用兰州重离子加速器国家实验室电子回旋共振离子源（ECRIS）原子物理平台,观测了200nm金膜基底上的金纳米颗粒经288keV的40Ar12＋离子束轰击后的熔化及再生长情况,通过原子力显微镜（AFM）表征和理论分析发现轰击后金纳米颗粒团簇首先熔化为单个金原子,然后自组装生成尺寸更大但尺寸不一的纳米颗粒,表明可在室温下控制纳米颗粒的尺寸。     

Pb纳米晶的制备及表征

以铅粒为起始原料，聚乙二醇为保护剂和抗氧化剂，采用液相分散法成功地制备出了铅纳米晶．并采用投射电子显微镜和X-射线粉末衍射仪对其形貌和结构进行了研究。试验结果表明：液相分散法制取的铅纳米晶粉是近球形的小颗粒。同时具有与原料铅完全相同的晶体结构。另外．在四球试验机上察了铅纳米晶的摩擦学性能。     

基于自组装金钯核壳纳米颗粒单层膜的光纤H2传感器

低维纳米材料的大比表面积极大提升了材料与环境气体分子的反应效率,对提高光纤氢气传感器中关键氢敏器件的灵敏度及响应速度有着至关重要的作用。提出了一种在油水界面自组装制备高性能金钯(Au-Pd)核壳纳米颗粒单层氢敏薄膜的方法,并制备了基于该薄膜的透射式光纤氢气传感器。实验中采用水热合成法制备粒径约12 nm的球形Au核,然后在Au核水溶液中加入Pd生长液,得到粒径约为20 nm的Au-Pd核壳纳米颗粒。采用十八胺修饰Au-Pd核壳纳米颗粒并通过相转移技术将颗粒转移到甲苯溶液中,最后在甲苯-水界面提拉制备覆盖率高并且空洞和堆积少的纳米颗粒单层氢敏薄膜。表征分析结果表明,形成的Au-Pd核壳纳米颗粒粒径均匀且结晶度好,制备的纳米颗粒单层薄膜排列致密覆盖率达87%。搭建了透射式光纤氢气器并测试了制备的Au-Pd核壳纳米颗粒单层膜在不同氢气浓度下的感氢响应特性。实验结果表明,单层纳米颗粒氢敏膜对4%的氢气响应时间约为3 s,对0.1%的氢气(氮气为载气)响应时间约为13 s,在多个循环的测试中表现出良好的稳定性,该传感器在低浓度氢气的快速、准确检测上具有良好的应用前景。     

Frabrication of Au Nanoparticles in Various Shapes and Their Application in Surface-enhanced Raman Scattering

Anisotropic metallic Nanoparticles (NPs) have unique optical properties, such as Surface Enhanced Raman Scattering (SERS)spectroscopy. In this paper, star-shaped and sphere gold NPs were prepared by seed-mediated growth and Frence methods respectively. The reaction process and the effect of reagent in seed-mediated growth of gold nanostar particles were systematically described. After fabricating NPs the authors test their Raman enhancement using Crystal Violet (CV) molecules apart. The experimental results indicated that star-shaped Au NPs had stronger Raman enhancement spectrum than that of sphere Au NPs.     

INTERACTION OF METHOTREXATE WITH DNA USING GOLD NANOPARTICLES AS A PROBE

□ The use of gold nanoparticles as a probe to investigate the interaction of DNA with methotrexate is reported. Methotrexate has widespread use in the treatment of tumors and auto-immune diseases, and is an anti-metabolite of folic acid, having a direct or indirect effect on various molecular targets, which influences DNA replication and cell proliferation by integrating between the spaces between adjacent DNA base pairs. A simple method to monitor the interaction of DNA with methotrexate was developed, using ultraviolet – visible spectroscopy and spectroflurometry with gold nanoparticles as the probe. In a mixture of DNA and methotrexate, as the proportion of free DNA increased, the absorption of gold nanoparticles decreased and the fluorescence intensity increased. This article confirmed that as the interaction between DNA and methotrexate increased, less free DNA was available to bind with gold nanoparticles present in solution, reducing the absorption and enhancing the fluorescence of the nanoparticles. The limit of detection and limit of quantification were 160 ng/mL and 50 ng/mL, respectively. The results demonstrated the use of gold nanoparticles as a probe for the interaction of DNA with methotrexate, which may be an important tool to measure drug-induced DNA damage.     

利用压电微泵驱动和脉动混合可控合成金纳米粒子

为了合成粒径均一、单分散性好的金纳米粒子,提出一种压电驱动式脉动微混合可控合成金纳米粒子的方法。该方法采用两腔三阀结构的压电微泵作为驱动源,结合Y形微混合器,基于两压电微泵脉动交叉式输出性能来实现多种不同混合模式的可控混合。利用Fluent软件对Y形微混合器内不同流量及频率下的混合效果进行了优化分析,优选出了压电微泵的控制参数。在实验室内设计、制作了用于金纳米粒子可控合成的系统样机,并开展了相应的金纳米粒子可控合成试验。试验结果表明：电压为40 V,频率为300 Hz时,合成的金纳米粒子粒径较为均一,分散性较好,该结果验证了文中所提方法的可行性。此方法亦可应用于其他纳米粒子的可控合成。     

激光刻蚀金银合金胶体的制备及其SERS应用

金属胶体是一种新兴的表面增强拉曼散射(SERS)活性衬底,利用激光液相刻蚀技术制备了金银合金胶体,并通过透射电镜、吸收光谱、表面增强拉曼散射光谱等手段对其特性进行表征。结果表明,合金粒子多数为球形颗粒,颗粒大小在5nm左右,并且有很好的分散性,等离子体共振吸收峰位于428nm。此外,该胶体表现出很好的表面增强拉曼散射活性,且性能稳定可在室温下长时间保存。     

有序金纳米棒阵列的超分辨成像

显微成像技术受限于光学成像系统的衍射极限，无法分辨亚波长尺度的结构。通过饱和散射抑制成像技术已经实现了单个纳米颗粒的超分辨成像，但是涉及到纳米颗粒集合，需要考虑纳米颗粒间的耦合作用。利用超越衍射极限的双光束方法，可以在有序金纳米棒阵列上实现远场超分辨光学成像。本文设计了纳米棒长径比为2的5×5金纳米棒阵列，通过矢量光场理论和热扩散理论计算了金纳米棒阵列在连续波激光下的热分布，并模拟了双光束激光即脉冲激发光和连续波抑制光下的散射成像。仿真结果显示，连续波激光能够有效抑制金纳米棒阵列对脉冲激光的散射，双光束方法实现了80 nm横向特征尺寸的超分辨成像。     

Segmentation of scanning electron microscopy images from natural rubber samples with gold nanoparticles using starlet wavelets

Electronic microscopy has been used for morphology evaluation of different materials structures. However, microscopy results may be affected by several factors. Image processing methods can be used to correct and improve the quality of these results. In this article, we propose an algorithm based on starlets to perform the segmentation of scanning electron microscopy images. An application is presented in order to locate gold nanoparticles in natural rubber membranes. In this application, our method showed accuracy greater than 85% for all test images. Results given by this method will be used in future studies, to computationally estimate the density distribution of gold nanoparticles in natural rubber samples and to predict reduction kinetics of gold nanoparticles at different time periods. Microsc. Res. Tech. 77:71–78, 2014. © 2013 Wiley Periodicals, Inc.     

Large-area topography analysis and near-field Raman spectroscopy using bent fibre probes

We present a method for combined far‐field Raman imaging, topography analysis and near‐field spectroscopy. Surface‐enhanced Raman spectra of Rhodamine 6G (R6G) deposited on silver nanoparticles were recorded using a bent fibre aperture‐type near‐field scanning optical microscope (NSOM) operated in illumination mode. Special measures were taken to enable optical normal‐force detection for control of the tip–sample distance. Comparisons between far‐field Raman images of R6G‐covered Ag particle aggregates with topographic images recorded using atomic force microscopy (AFM) indicate saturation effects due to resonance excitation.     

Quantitative detection of gold nanoparticles on individual, unstained cancer cells by scanning electron microscopy

Gold nanoparticles are rapidly emerging for use in biomedical applications. Characterization of the interaction and delivery of nanoparticles to cells through microscopy is important. Scanning electron microscopes have the intrinsic resolution to visualize gold nanoparticles on cells. A novel sample preparation protocol was developed to enable imaging of cells and gold nanoparticles with a conventional below lens scanning electron microscopes. The negative influence of 'charging' on the quality of scanning electron microscopes' images could be limited by deposition of biological cells on a conductive (gold) surface. The novel protocol enabled high-resolution scanning electron microscopes' imaging of small clusters and individual gold nanoparticles on uncoated cell surfaces. Gold nanoparticles could be counted on cancer cells with automated routines.