脉冲激光沉积VN/Ag复合薄膜的组织及摩擦学性能研究

利用脉冲激光沉积技术制备了不同Ag含量的VN/Ag复合薄膜,利用扫描电子显微镜、X射线衍射仪、纳米力学测试系统等设备表征薄膜的组织结构、成分、表面形貌及力学性能,利用UMT-3摩擦试验机考察薄膜在室温至900℃下的摩擦学性能。结果表明,随着Ag含量的增多,薄膜的组织形貌变差,硬度及弹性模量降低。当Ag含量为16%(原子分数)时薄膜在试验温度范围内的摩擦学性能最佳。由于Ag在低温的润滑特性及高温摩擦化学反应生成了新的润滑相,如V2O5、V6O11、V6O13、Ag3VO4、AgVO3等,使得摩擦系数随温度的升高而逐渐降低,在900℃下取得最低值0.08,实现了宽温域内的连续润滑。     

银/氯化银电极用于监测混凝土中氯离子含量的研究

采用干湿循环渗透法,通过实验室制备的银/氯化银电极来监测混凝土中的氯离子含量,测试了电极的响应性能和长期稳定性,研究了总氯离子含量与自由氯离子含量之间、总氯离子含量与电位之间的关系。结果表明:银/氯化银电极电位能比较好地监测到混凝土中氯离子含量变化的过程,具有良好的长期稳定性能。总氯离子含量随自由氯离子含量的增加而增加,两者之间呈现幂函数的规律。总氯离子含量随电位上升而下降,两者之间呈指数函数的规律。     

不同合成过程对溶胶-凝胶法制备的ZnO/Ag纳米复合材料光催化性能的影响

以乙酸锌、硝酸银为前驱体,二乙醇胺作为稳定剂,利用溶胶-凝胶法分别采用一步法和两步法制备得到ZnO以及ZnO/Ag纳米复合粉体。所有ZnO/Ag复合物中Ag的含量均为3%(摩尔分数)。对所制备样品的结构和光学性质通过XRD、SEM、TEM、XPS、PL、UV-vis进行了表征,进而以甲基橙为模拟污染物进行了光催化测试。结果表明,不同方法制备得到的ZnO/Ag纳米粉体晶粒均匀,无明显团聚现象,面心立方结构的金属Ag吸附在纤锌矿结构的ZnO表面形成异质结。与纯ZnO相比,掺Ag极大地改善了样品在紫外光下的光催化活性。对不同合成工艺的比较表明,用溶胶-凝胶一步法制备的ZnO/Ag复合物的光催化活性最高,经紫外光照射70min可完全降解甲基橙。     

Ag纳米颗粒等离激元光散射增强对Si刻蚀形貌的影响机制

通过实验与有限元(FDTD)模拟系统研究了不同粒径尺寸的Ag纳米颗粒在P(100)Si表面刻蚀过程中等离激元光散射增强对刻蚀孔形貌的影响。SEM结果表明,刻蚀孔由与粒径尺寸接近的垂直孔演化为一种上大下小的火炬状形貌特征孔,该孔的直径与纳米颗粒尺寸散射半径相仿。模拟不同粒径的Ag纳米颗粒进入刻蚀孔后的光散射特征,证实了Ag纳米颗粒等离激元散射对刻蚀孔初期形成的重要作用。分析表明,基于光照条件下电子-空穴的激发特征,刻蚀孔的形貌主要依赖Ag纳米颗粒等离激元散射的光增强,即通过改变入射光频率以及Ag纳米颗粒粒径可以有效地调控Si表面形貌特征。Ag纳米颗粒等离激元光散射增强技术在Si基太阳能电池、发光二极管(LED)器件等领域有潜在应用前景。     

In-situ synthesis of TiO2 nanostructures on Ti foil for enhanced and stable photocatalytic performance

TiO_2 nanostructures with strong interfacial adhesion and diverse morphologies have been in-situ grown on Ti foil substrate through a multiple-step method based on conventional plasma electrolytic oxidation(PEO) technology, hydrothermal reaction and ion exchange process. The PEO process is critical to the formation of TiO_2 seeding layer for the nucleation of Na_2Ti_3O_7 and H_2Ti_3O_7 mediates that are strongly attached to the Ti foil. An ion exchange reaction can finally lead to the formation of H_2Ti_3O_7 nanostructures with diverse morphologies and the calcination process can turn the H_2Ti_3O_7 nanostructures into TiO_2 nanostructures with enhanced crystallinity. The morphology of the TiO_2 nanostructures including nanoparticles(NP), nanowhiskers(NWK), nanowires(NW) and nanosheets(NS) can be easily tailored by controlling the NaOH concentration and reaction time during hydrothermal process. The morphology, composition and optical properties of TiO_2 photocatalysts were analyzed using scanning electron microscope(SEM), X-ray diffraction(XRD), photoluminescence(PL) spectroscopy and UV–vis absorption spectrum. Photocatalytic tests indicate that the TiO_2 nanosheets calcined at 500?C show good crystallization and the best capability of decomposing organic pollutants. The decoration of Ag cocatalyst can further improve the photocatalytic performance of the TiO_2 nanosheets as a result of the enhanced charger separation efficiency. Cyclic photocatalytic test using TiO_2 nanostructures grown on Ti foil substrate demonstrates the superior stability in the photodegradation of organic pollutant, suggesting the promising potential of in-situ growth technology for industrial application.     

全固态裸露式Ag／AgCl参比电极的研制及应用

该文报道了一种树脂接界全固态裸露式Ag／Agcl参比电极,勿需电镀氯化,制备工艺简单,性能稳定,是对电解型Ag／AgCl参比电极的一大改进。可代替饱和甘汞电极作为通用型参比电极,同时可减少汞对环境所造成的二次污染,在温度大于75℃时仍能保持良好性能,突破了甘汞电极的局限。     

基于核酸识体的电化学免疫传感器用于血小板源性生长因子的检测

该文提出了一种新颖的、高灵敏度的基于核酸识体和银沉积的电化学免疫传感器用于人体血小板源生长因子BB(PDGF-BB)的检测.首先在电极的表面固定抗体,然后与抗原、生物素标记的核酸识体形成免疫夹心复合物,再利用生物素和亲合素的特异性反应把亲合素标记的碱性磷酸酶固定到电极上,然后把得到的产物在底物溶液中进行银沉积,最后利用电化学方法对沉积到电极表面的银进行检测以达到检测PDGF-BB的目的.实验对固定抗体浓度和生物素标记核酸识体的浓度两个条件进行了优化.实验结果表明PDGF-BB的浓度在1～1000 ng/mL的范围具有良好的线性关系,最低检测下限可达0.8 ng/mL.该方法具有高灵敏度和稳定性,在临床上具有广阔的应用前景.     

The structure and properties of Ag(Nb0.8Ta0.2)O3 ceramic doped with MnNb2O6

The influences of doping of MnNb2O6 on the structure and dielectric properties of Ag(Nb0.8Ta0.2)O3 were illustrated. Ag(Nb0.8Ta0.2)O3 samples doped with different amount of preformed MnNb2O6 (1 mol%, 2 mol%, 3 mol%, 4 mol%, 6 mol%, 8 mol%) were prepared by traditional solid-state reaction method and characterized by XRD, SEM and EDS, and the dielectric properties of samples were compared. The experiment results indicated that when the doping amount of MnNb2O6 was greater than 3 mol%, second phase appeared because of the solid solution limit. The permittivity of the Ag(Nb0.8Ta0.2)O3 samples doped with MnNb2O6 firstly increased and then decreased with the sintering temperature, while the dielectric loss decreased first, and then increased slightly. 1 100 ℃ seems to be the most proper sintering temperature for most of the samples. When the amount of MnNb2O6 is about 3 mol%, the samples have the best dielectric properties, larger permittivity and smaller dielectric loss.     

基于FDTD的三角形银纳米颗粒阵列等离子共振吸收特性的模拟

利用时域有限差分法,数值模拟了银纳米三角阵列的等离子共振吸收特性,仿真计算了银纳米颗粒尺寸大小对阵列等离子体共振的影响.数值计算结果表明,三角形银纳米颗粒阵列的等离子共振吸收峰随颗粒尺寸的增大而红移,可通过改变颗粒大小调节共振吸收波长数值以用于不同的应用研究.基于FDTD理论模拟的计算结果与实验规律基本相符,并较好地阐释了银纳米三角有序阵列表面等离子共振吸收峰的频移与其纳米粒子长径比之间的一些依赖关系,此结论将有利于纳米光传感器应用的进一步探索研究.