Hydrothermal synthesis and photoluminescence behavior of CeO<Subscript>2</Subscript> nanowires with the aid of surfactant PVP

Well-crystalline CeO₂ nanowires were prepared via a surfactant-assisted hydrothermal process. Reaction temperature and reaction time were changed for the determination of optimal synthesis parameters. The as-obtained products were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and field emission scanning electron microscopy (FESEM). The results show that single crystal CeO₂ nanowires with high yield and good uniformity can be obtained hydrothermally at 180°C for 12 h with the aid of 2.0 g surfactant (polyvinyl pyrrolidone, PVP). The role of PVP was then discussed and a possible growth mechanism was proposed. Moreover, room temperature photoluminescence (PL) spectra were obtained for these CeO₂ nanowires, which are believed to be related to the abundant defects in these nanostructures.     

9,10-二(3,5-二氟苯乙烯基)蒽有机纳米线的制备与性质表征

利用再沉淀法制备9,10-二(3,5-二氟苯乙烯基)蒽(TFDSA)有机纳米线,并通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)和光致发光光谱(PL)表征所制备的纳米线.结果表明:纳米线表面光滑,长度为20~30μm,宽度为400nm,具有较强的绿色荧光发射,发光峰位于538nm处;将单根TFDSA纳米线作为有源波导可在亚微米量级进行光传播.     

磷酸处理氧化铝模板对Ag纳米线形貌的影响

以磷酸超声处理的多孔阳极氧化铝为模板,用乙二醇在模板的纳米孔道内还原Ag+制备Ag纳米线.用X射线衍射光谱(XRD)、透射电子显微镜(TEM)等检测手段对产物进行了表征,并与未处理的多孔阳极氧化铝为模板在相同条件下制备的样品进行了比较.结果表明,用磷酸处理氧化铝模板后得到的Ag纳米线具有更大的长径比,所得Ag纳米线具有面心立方的晶体结构,长度大于5μm,单体纳米线的直径大约为60 nm.     

Preparation of spherical ultrafine copper powder via hydrogen reduction-densification of Mg(OH)2-coated Cu2O powder

A novel process was developed to produce spherical copper powder for multilayer ceramic capacitors (MLCC). Spherical ultrafine cuprous oxide (Cu₂O) powder was prepared by glucose reduction of Cu(OH)₂. The Cu₂O particles were coated by Mg(OH)₂ and reduced to metallic copper particles. At last, the copper particles were densified by high-temperature heat treatment. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), tap density, and thermogravimetry (TG). It is found that the shape and size distribution of the copper powder are determined by the Cu₂O powder and the copper particles do not agglomerate during high-temperature heat treatment because of the existence of Mg(OH)₂ coating. After densification at high temperature, the particle tap density increases from 3.30 to 4.18 g/cm³ and the initial oxidation temperature rises from 125 to 150°C.     

Fabrication and photoluminescence of GaN nanowires prepared by ammoniating GaeO3/BN films on Si substrate

GaN nanowires were successfully prepared on Si（111） substrate through ammoniating Ga203/BN films deposited by radio frequency magnetron sputtering system. The synthesized nanowires were confirmed as hexagonal wurtzite GaN by X-ray diffraction, selected-area electron diffraction and Fourier transform infrared spectra. Scanning electron microscopy and transmission electron microscopy revealed that the grown GaN nanowires have a smooth and clean surface with diameters ranging from 40 to 160 nm and lengths typically up to several tens of micrometers. The representative photoluminescence spectrum at room temperature exhibited a strong UV light emission band centered at 363 nm and a relative weak purple light emission peak at 422 nm. The growth mechanism is discussed briefly.     

液相法制备铁钴合金纳米线/棒

报道了一种简单的液相还原法制备铁钴合金纳米线/棒.以十六烷基三甲基溴化铵(CTAB)为表面活性剂,在90℃时利用水合肼还原Fe2 和Co2 的水和正辛烷的混合溶液得到铁钴合金纳米线/棒.所得样品经X-射线粉末衍射(XRD) ,透射电子显微镜(TEM) ,选区电子衍射(SAED)和振动样品磁强计(VSM)等表征,结果表明延长反应时间,一维铁钴合金纳米结构直径增大但长度没有明显变化,一维铁钴合金纳米材料的室温矫顽力高于体相铁钴合金.该铁磁性纳米线/棒有望应用于催化、生物技术和磁记录器件等领域.     

Polypyrrole-coated styrene-butyl acrylate copolymer composite particles with tunable conductivity

A series of near or monodisperse styrene-butyl acrylate (SBA) copolymer latex particles with different butyl acrylate contents were coated with polypyrrole. The structure of the SBA/PPy composites was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC) andstandard fourprobe method. The core-shell morphology of the SBA/PPy composite particles was confirmed. The result of DSC showed that TR of the composite is mainly determined by the core component. The effects of the concentration of polypyrrole, the butyl acrylate content in SBA copolymer and the nature of the counter-anion on the electrical conductivity of compression-moulded samples were studied. It was first found that the electrical conductivity of the samples can be tuned by varying the butyl acrylate content in SBA copolymer and the highest conductivity of the core-shell composite was 0.17 S. cm^-1     

ZnO纳米线的三阶非线性光学性质

用微乳液法制备ZnO纳米线, 对材料的形貌和结构进行透射电镜表征和Raman光谱表征, 并设计超短脉冲Z扫描实验, 研究ZnO纳米线的三阶非线性光学特性. 结果表明：制备的材料尺寸均一、结晶良好, 具有较好的紫外区激子发光特性; ZnO纳米线三阶非线性光学折射率为正值, 其三阶非线性光学极化率比体相ZnO高约3个数量级. 因此制备的ZnO纳米线材料具有较好的光学和非线性光学性质.     

ZnO纳米线的三阶非线性光学性质

用微乳液法制备ZnO纳米线, 对材料的形貌和结构进行透射电镜表征和Raman光谱表征, 并设计超短脉冲Z扫描实验, 研究ZnO纳米线的三阶非线性光学特性. 结果表明：制备的材料尺寸均一、结晶良好, 具有较好的紫外区激子发光特性; ZnO纳米线三阶非线性光学折射率为正值, 其三阶非线性光学极化率比体相ZnO高约3个数量级. 因此制备的ZnO纳米线材料具有较好的光学和非线性光学性质.     

热蒸发法制备TeO_2纳米线的生长机理

以金属碲粉为原料,在450℃下采用热蒸发法在镀金玻璃基板上成功合成TeO_2纳米线,利用X射线衍射、扫描电子显微镜、透射电子显微镜对TeO_2纳米线的结构和形貌进行表征,并对其生长机理进行探讨.研究结果表明,具有四方相晶体结构的TeO_2纳米线直径在70~200 nm之间,长度在几百微米至2 mm.通过对不同生长时间所获得产物的形貌观察,对TeO_2纳米线的生长过程进行了分析,推断TeO_2纳米线是通过气-固机制进行生长,镀金薄膜可能只是起到诱导和加速TeO_2纳米线生长的作用.     

无电化学沉积法合成铜纳米线

采用无电化学沉积法制备铜纳米线,与电化学沉积法不同,无电化学沉积法不需要在通孔模板的一面溅射一层导电金膜作为阴极,以及持续供给电力才能完成纳米线的合成.考察沉积时间、敏化液等因素对铜纳米线制备的影响.使用扫描电子显微镜(SEM),X射线衍射(XRD)对样品其进行检测,结果表明,无电化学沉积法首先形成纳米粒子,随着沉积时间的延长,纳米粒子逐渐融合形成纳米管、纳米线.制备的铜纳米线为多晶态结构.在没有模板限制的情况下,铜原子自催化生长形成类似于花瓣的结构.用95%乙醇代替水配制的敏化液性质较稳定,但是,与以水配制的敏化液相比,在大约相同的沉积时间条件下较不易形成纳米线.     

磁性氧化铁纳米线的制备与表征

通过溶胶-凝胶法在氧化铝模板（AAO）中制备出了磁性Fe_2O_3纳米线阵列,然后去除AAO模板得到磁性Fe_2O_3纳米线。用SEM,TEM,FTIR,EDX,VSM对磁性纳米线的形貌、微结构和磁性能进行表征。SEM和TEM结果显示磁性纳米线的直径约为50～80nm,长度在8～10μm,长径比为120～180;FTIR和EDX结果表明制备的产物是磁性Fe_2O_3纳米线;VSM结果表明磁性氧化铁纳米线阵列存在明显的磁各向异性。此外,采用Zeta电位仪对磁性Fe_2O_3纳米线表面的电性进行了研究,结果表明纳米线表面带正电荷,有利于和动物细胞相结合。     

激光微织构泡沫铜的氧化铜纳米线制备及其光催化性能研究

本文采用激光织构与热氧化法相结合,以泡沫铜为基底制备具有微阵列结构的氧化铜纳米线(CuO NWs).采用扫描电子显微镜(SEM)、X射线能谱仪(EDS)和X射线衍射仪(XRD)对样品表面形貌及成分进行表征,讨论激光织构表面微结构对氧化铜纳米线生长的促进作用,设计不同的加工参数研究激光织构对氧化铜纳米线生长的影响,并通过光催化降解甲基橙溶液考察了CuO NWs的光催化性能.实验结果表明,经过激光织构的泡沫铜能增大纳米线的生长面积,提高样品表面氧元素的含量,有效地促进生长过程中氧化铜纳米线长度和密度的提高.不同的激光参数对纳米线的生长产生一定影响,具有良好的调控作用.CuO NWs光催化降解甲基橙的降解率可达97%,循环测试5次后的降解率仍可保持在96%,可见其稳定性良好,而且其片状结构更易回收,重复利用率高,具有优异的光催化性能.     

纳米空心球铜粉的制备

金属铜空心微纳米球可望在微电子、微系统和生命科学等诸多前沿领域中发挥更为重大的作用。文章采用一种简单的液相还原方法,在通氨气保护的条件下,用水合肼还原乙酸铜,制备出粒径400 nm左右的铜空心球,采用TEM、SEM和XRD等方法对产物的结构进行了表征,分析了回流温度、还原剂用量对产物结构的影响。     

CNTs/mesostructured silica core-shell nanowires via interfacial surfactant templating

Carbon nanotubes (CNTs)/mesostructured silica core-shell nanowires with a carbon nanotube core and controllable highly ordered periodic mesoporous silica shell are syntheiszed via the interfacial surfactant template. The core-shell nanowires are characterized by transmission electron microscope (TEM), X-ray diffraction pattern (XRD) and nitrogen sorption/desorption. The results indicate that the core-shell nanowires have highly ordered periodic mesoporous silica shell (space group p6mm), high BET surface area and narrow pore size distribution. Moreover, the morphology of core-shell nanowires can be controlled by the pH value. The core-shell nanowires have promising applications in biosensors, nanoprobes and energy storage due to their good dispersibility in polar solvents. Supported by the Australian Research Council (ARC) through Discovery Project program (DP0452461)     

纯铜表面纳米化的微观结构演化及其力学性能研究

利用表面机械滚压处理（surface mechanical rolling treatment,SMRT）工艺在纯铜表面制备出梯度纳米结构层,获得了最表层为取向随机的纳米晶粒、亚表层的晶粒尺寸在厚度方向上呈梯度分布的结构层。采用光学显微镜、扫描电子显微镜、透射电子显微镜对微观组织进行表征,研究了晶界、位错、孪晶界等微观结构的演化。通过改变SMART工艺参数,在纯铜表面制备出不同厚度的梯度纳米结构层,对比分析了梯度纳米结构层厚度对纯铜力学性能的影响。结果表明：经SMRT后,试样距表面大约5 μm处的显微硬度高达1.56 GPa,其横截面的硬度随着距表面深度增加呈递减趋势;相比于粗晶铜,SMRT后纯铜的屈服强度提高了2倍多,而塑性损失很少,并且SMRT后纯铜的屈服强度随着梯度纳米结构层厚度的增加而提高。     

以DNA为模板Pd纳米线的电化学制备及其性质

以DNA为模板,采用电化学方法制备出Pd纳米线,通过透射电镜(TEM)和X-射线衍射(XRD)对产物进行了表征,得到粒径大约50nm、长度3.0 um的Pd纳米线.同时讨论了不同实验条件对纳米线结构的影响,并对所制备出的纳米线的电化学性质进行了探讨,对H2O2具有催化响应.     

Characterization and application of Cu based superhydrophobic catalyst

Superhydrophobic (SH) Copper salt was prepared with the help of three different chemical etching agents and characterized by various analytical techniques like Fourier transform infrared (FTIR) spectroscopy, UV–visible spectroscopy, X-ray diffractogram (XRD), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). The SH nature of the material was confirmed by water contact angle (WCA) measurement. Cu surface with the etching agent was made to produce SH Cu surface. Among the chemical etching agents the system with Cl, F and Si exhibited the SH character. The SH hierarchically structured heterogeneous materials produced were used as a catalyst for the reduction of Cr(VI) and 4-nitrophenol (NiP). The catalytic activities of the materials were compared on the apparent rate constant (k_app) and induction time (T_i). Among the catalyst systems used, the Cu-Trichoropentaflourooctylsilane (TCPFOSi) system exhibited the highest k_app and T_i values.     

Fabrication and photoluminescence of GaN nanowires prepared by ammoniating Ga_2O_3/BN films on Si substrate

GaN has been considered to be the most promising optoelectronic material for such applications as light emitting diodes (LEDs), laser diodes (LDs) as well as high power electronic devices, due to its large direct energy band gap of 3.39 eV at room tempera…     

Antibacterial and corrosive properties of copper implanted austenitic stainless steel

Copper ions were implanted into austenitic stainless steel (SS) by metal vapor vacuum arc with a energy of 100 keV and an ions dose range of (0.5-8.0)×1017 cm-2. The Cu-implanted SS was annealed in an Ar atmosphere furnace. Glancing X-ray diffraction (GXRD), transmission electron microscopy (TEM) and Auger electron spectroscopy (AES) were used to reveal the phase compositions, microstructures, and concentration profiles of copper ions in the implanted layer. The results show that the antibacterial property of Cu-implanted SS is attributed to Cu_9.9Fe_0.1, which precipitated as needles. The depth of copper in Cu-implanted SS with annealing treatment is greater than that in Cu-implanted SS without annealing treatment, which improves the antibacterial property against S. aureus. The salt wetting-drying combined cyclic test was used to evaluate the corrosion-resistance of antibacterial SS, and the results reveal that the antibacterial SS has a level of corrosion-resistance equivalent to that of un-implanted SS.