CoPt_3纳米线阵列的制备及特性研究

在具有纳米级孔洞的多孔氧化铝模板上,用电化学方法成功地制备了CoPt3纳米线有序阵列复合膜。分别用透射电子显微镜(TEM)、选区电子衍射(SAED)、X射线衍射(XRD)、振动样品磁强计(VSM)和SQUID对样品进行了测试与表征。形貌观察和物相分析表明,模板中的CoPt3纳米线构成的阵列,排列均匀有序,长约1.5微米,直径35纳米;而纳米线中的CoPt3为L12无序结构。磁性研究表明,纳米线的无序晶体结构决定了纳米线阵列弱的磁晶各向异性;同时纳米线中部分小晶粒在400K左右表现出顺磁性,导致纳米线阵列居里温度的下降。比较低温和室温下的磁滞回线,低温下有大的矫顽力,从另一方面证明纳米线中的小晶粒确实存在相转变。     

氧化时间和温度对Si基AAO模板制备的影响

采用一次阳极氧化法,通过电解P型<100>晶向Si衬底上的高纯Al膜,在40V下,0.3M草酸中制备了Si基anodic aluminum oxide(AAO)模板。在Si基Al氧化过程中,通过电流密度随时间实时变化曲线的分析,研究了Si基AAO的生长机理。实验发现,电解液温度对Si基AAO制备的影响很大,在30℃下的氧化速度是在10℃下的5倍多。     

Improvement of sensitivity in an interferometry by controlling pore size on the anodic aluminum oxide chip pore-widening technique

The pore size of an anodic aluminum oxide (AAO) chip, as well as uniform pore distribution, is one of the key parameters that should be adjusted, by choosing the appropriate etching conditions, in order to enhance the sensitivity of an interferometer. In this study, the pore size of AAO chips was optimized and characterized in order to lower the detection limit of prostate specific antigen (PSA) in an interferometric immunoassay system. After pore widening for 30–50 min, the AAO pore size was increased approximately 2-fold larger than that before pore widening. A large increase in effective optical density (ΔEOT) was obtained from the AAO chip fabricated by pore-widening technique, which thereby lowered the PSA detection limit. The present study results are not sufficiently validated to enable the immediate application to immunoassay for prostate cancer (PCa) screening, but they do demonstrate that controlling pore size can positively affect the sensitivity and lower the detection limit.     

Distinction of heterogeneity on Au nanostructured surface based on phase contrast imaging of atomic force microscopy

The discrimination of the heterogeneity of different materials on nanostructured surfaces has attracted a great deal of interest in biotechnology as well as nanotechnology. Phase imaging through tapping mode of atomic force microscopy (TMAFM) can be used to distinguish the heterogeneity on a nanostructured surface. Nanostructures were fabricated using anodic aluminum oxide (AAO). An 11-mercaptoundecanoic acid (11-MUA) layer adsorbed onto the Au nanodots through self-assembly to improve the bio-compatibility. The Au nanostructures that were modified with 11-MUA and the concave surfaces were investigated using the TMAFM phase images to compare the heterogeneous and homogeneous nanostructured surfaces. Although the topography and phase images were taken simultaneously, the images were different. Therefore, the contrast in the TMAFM phase images revealed the different compositional materials on the heterogeneous nanostructure surface.     

连续式硝化调试新工艺在焦化厂AAO污水处理中的应用

介绍连续式硝化调试新工艺在柳钢焦化厂AAO污水处理中的开发、应用情况。     

Electrocatalytic applications of a vertical Au nanorod array using ultrathin Pt/Ru/Pt layer-by-layer coatings

This study compared the electro-oxidation of carbon monoxide adlayers formed on a codeposited and a layer-by-layer deposited Pt/Ru thin overlayer on a Au surface. Vertical arrays of smooth and nanoporous Au nanorods were used as a platform for the Pt/Ru overlayer-coating. The vertical arrays of Au nanorods served as high surface area templates, where the surface area could be controlled as a function of the rod length in a given geometrical surface area. A coating of the Au nanorod arrays with Pt/Ru via Cu underpotential deposition (UPD) steps allowed control of the overlayer thickness with an ultrathin film nature. The electronic modification of the Pt overlayer with a Ru underlayer became increasingly weaker with increasing Pt overlayer thickness. The thick Pt overlayer exhibited CO electro-oxidation that was similar to the electro-oxidation profile on the Pt bulk surface. Coating of the Au nanorod arrays with Pt/Ru through Cu UPD steps demonstrated an optimal electronic response between the Pt outer overlayer and the underlying Ru layer. It is expected that an ultrathin overlayer-coating strategy can be expanded to nanoporous Au nanorod arrays. These finding will facilitate better design of highly active Pt/Ru composite nanostructures for electrocatalysis.     

Template Synthesis of Carbon Nanofibers Containing Linear Mesocage Arrays

Carbon nanofibers containing linear mesocage arrays were prepared via evaporation induced self-assembly method within AAO template with an average channel diameter of about 25 nm. The TEM results show that the mesocages have an elongated shape in the transversal direction. The results of N₂ adsorption–desorption analysis indicate that the sample possesses a cage-like mesoporous structure and the average mesopore size of the sample is about 18 nm.     

Fabrication of gold sub-wavelength pore array using gas-assisted hot embossing with anodic aluminum oxide (AAO) template

This paper reports a novel and effective method for the fabrication of gold sub-wavelength pore array using gas-assisted hot embossing. The novel fabrication comprises the fabrication of AAO template with high order pore array, sputter-coating of gold and gas-assisted hot embossing. AAO template is fabricated by a two-step anodization process. It is then coated with gold (100 nm thick). The gold sub-wavelength pore array is finally formed by using gas-assisted hot embossing process. The transmission spectra of gold sub-wavelength pore array are measured in several conditions such as air, water and glycerol/water mixture. The detection shows significant shift in the wavelength of resonance peak. The gold sub-wavelength pore array can be employed as optical biosensors.     

Polyacrylonitrile-based nanofibers—A state-of-the-art review

Polyacrylonitrile (PAN), a well-known polymer with good stability and mechanical properties, has been widely used in producing carbon nanofibers (CNFs) as these have attracted much recent attention due to their excellent characteristics, such as spinnability, environmentally benign nature and commercial viability. Among the various precursors to produce CNFs, PAN has been extensively studied due to its high carbon yield and flexibility for tailoring the structure of the final CNFs as well as the ease of obtaining stabilized products due to the formation of a ladder structure via nitrile polymerization. In view of this, they have applications in areas such as electronics, tissue engineering, membrane filtration and high performance composites. This review presents various combinations of PAN and PAN-based precursors in producing CNFs from the PAN homopolymer or its modified precursors, copolymers, blends and various composites. Various modifications of PAN and their future prospects in different scientific and technological disciplines are addressed.