Quantification of lycopene in tomato products: comparing the performances of a newly proposed direct photothermal method and high‐performance liquid chromatography

A new photothermal method suitable for direct, accurate and highly reproducible quantitative measurements of lycopene in tomato products has been introduced. The intrinsic precision of the method is typically better than 0.2%; the repeatability of determination is comparable to that of high‐performance liquid chromatography, with 0.86% least overall error. Copyright © 2005 Society of Chemical Industry     

高密存储介质磁性纳米颗粒薄膜与纳米超晶格结构研究进展(英文)

钴基合金和铁基合金磁性纳米颗粒薄膜和纳米超晶格结构,由于具有较高的矫顽力和各向异性能,较小的粒子尺寸分布和能形成“单域”结构等特性,从而成为颇有潜力的高密存储介质。最近几年,人们竞相研究其制备方法,其中主要包括真空淀积法、液相化学合成法和离子注入法等,采用各种措施来提高存储介质的热稳定性和其他磁学性能,并取得巨大进展。     

制备Co-P纳米粒子的新方法及其表征

采用化学镀技术制备了金属Co -P纳米粒子 ,元素分析表明 ,其成分为Co :95 6%、P :4 31%。由X -射线衍射确认晶相为六方密排Co。对其形状和大小进行了透射电镜和激光散射分析。确认Co -P纳米粒子为球形 ,平均粒径为 37 0nm。在正已烷中存在软团聚 ,团聚平均尺寸约 65 0nm。     

纳米Fe基磁流体制备

文中采用直流电弧等离子体法制备了铁的纳米粒子,平均粒度小于60nm。文中选择适当的表面活性剂、载液和纳米粒子,制备了磁流体密封材料,并进行了抗酸、碱性和煤油的研究。     

Preparation of Silica Nanostructured Spheres by Sol Spray Drying

Silica nanostructured spheres were obtained by spray drying of silica sol prepared in situ. Their morphologies were significantly affected by the aggregation of the primary particles in the sol. They had the mode of the pore sizes which was about the same order as Laser Particle Size Analyzer (LPA) diameter. Increasing the mixing ratio of the larger particles (20 nm) to smaller ones (7 nm) decreased the Brunauer, Emmett and Teller (BET) specific surface area, as expected. Pore volume decreased with the pore size distribution broadened and the mean pore diameter was not affected by the increase, due to the decrease in aggregation of the primary particles. Either the increase in the drying temperature and use of ethanol as a cosolvent made the agglomerates hollower, the larger of which with thinner shell transformed to doughnut type agglomerates, due to the structural and hydrodynamic instabilities.     

Synthesis of a New Optoelectronic Material Based on Oriented Adsorption of Dyes to Nanoparticles Surface

Synthesis of the optoelectronic storage material with structure for coating by nanosized metal and azo-dye was reported. The characterization of composites was made by using transmission electron microscope （TEM）, ultraviolet-visible spectrometer （UV-Vis） and thermogravity analyzer （TGA）. It is found that, due to the specific structure, in which azo-dye molecules are oriented and adsorbed on the spherical surface of nanosized metal, the absorption maximum of azo-dye methyl orange shift towards shorter wavelength band. The experimental results show that the proposed technique here wouM offer a promising way to synthesize short wavelength optoelectronic storage material by doping of metal nanoparticles coated with dyes in polymer. Furthermore, the composites based on the structure can present excellent thermal properties suitable for the requirements of optical storage. This new type of material is capable of matching semiconductor laser （GaN） in optoelectronic storage technology.     

A hydrogen peroxide sensor based on the peroxidase activity of hemoglobin immobilized on gold nanoparticles-modified ITO electrode

A novel ITO electrode surface modified with spherical and rod-shaped gold nanoparticles was prepared by a surfactant-assisted seeding growth approach, which provided a biocompatible matrix for the immobilization of hemoglobin (Hb). By electrochemical impedance measurements, gold nanoparticles modification and Hb immobilization on the electrode surfaces were characterized using [Fe(CN)₆]³⁻/[Fe(CN)₆]⁴⁻ redox probe. Owing to the promoted electron transfer of Hb by gold nanoparticles, the Hb immobilized gold nanoparticles-modified ITO (Hb/Au/ITO) electrode exhibited an effective catalytic response to the reduction of H₂O₂ with good reproducibility and stability. The linear relationship existed between the catalytic current and the H₂O₂ concentration in the range of 1 × 10⁻⁵ to 7 × 10⁻³ M. The detection limit (S/N = 3) was 4.5 × 10⁻⁶ M.     

Synthesis of oligocaprolactone vinyl ether macromonomers and their use for indomethacin encapsulation in polymer nanoparticles based on polycaprolactone macromonomer–maleic anhydride–N‐vinyl pyrrolidone terpolymers

Oligocaprolactone macromonomers functionalized with vinyl ether have been synthesized by polymerization of ε‐caprolactone in the presence of hydroxy ethyl or butyl vinyl ether and characterised by NMR and Maldi time‐of‐flight mass spectroscopy. These macromonomers have been copolymerized with maleic anhydride and N‐vinyl pyrrolidone to give terpolymers, which have been used to obtain nanoparticles by the phase‐separation‐dialysis method. Previously dissolving indomethacin in the terpolymer solution allows one to encapsulate the drug inside the nanoparticles. Copyright © 2005 Society of Chemical Industry     

The influence of gold nanoparticle modified electrode on the structure of mercaptopropionic acid self-assembly monolayer

The comparison of assembly structure and property of mercaptopropionic acid (MPA) self-assembled monolayers (SAMs) on gold nanoparticle modified electrode (nanogold electrode) with that on planar gold electrode was studied by cyclic voltammetry (CV). The electron transfer of through the MPA SAMs and Cu underpotential deposition (UPD) on MPA-covered electrode indicated that MPA molecules assemblied on the planar gold electrode could form a very compact layer, which could surpass the electron transfer K₃Fe(CN)₆ greatly, whereas on the surface on the nanogold, which curvature make the compact packing loose. The reductive desorption in 0.5 M KOH and oxidative desorption in phosphate buffer solution (PBS) (pH 6.8) showed that gold nanoparticles could enhance the Au-S bond and stabilize the MPA molecules.