Helium atoms were implanted into niobium-doped tungsten and pure tungsten via ion implantation, and the effect of helium implantation on mechanical properties of two types of sample was studied by X-ray photoelectron spectroscopy, scanning electron microscope and nano-hardness tester. The results clearly show that the surface hardness and elastic modulus of tungsten are improved by implanted niobium ions, and the degradation of mechanical properties is mitigated comparing to pure tungsten under identical helium implantation fluence. It can be concluded that the defects induced by niobium implantation improved the mechanical properties of tungsten by obstructing the slip of dislocation.
Large amounts of WO3 nanowires were prepared on silicon substrates by electrospinning followed by appropriate calcinations in air using ammonium metatungstate（AMT） as WO3 source. Tunable densities and diameters of WO3 nanowires were achieved by changing the electrospinning time and the concentration of AMT in precursor solution.TG/DSC analysis was used to direct the heating process. The effects of both solvent ratio and heating process on the morphology of the obtained nanowires were investigated. The morphology, structure, and chemical compositions of the tungsten oxide were characterized by SEM, XRD, and EDX, respectively. Results showed that monoclinic phase WO3 nanowires with diameters ranging from 100 to 200 nm were obtained after the appropriate heating process when the AMT concentration of the precursor solution increased from 10 to 20 wt%. The photocatalytic performance of the obtained WO3 nanowires under visible light irradiation（〉420 nm） was investigated in the degradation of Rhodamine B at room temperature in air.
Copper oxide nanowires and nanoparticles were fabricated through electrospinning followed by calcinations in different heating conditions.It was found that the solution viscosity and environment humidity had great impact on the morphologies of precursor nanowires,and the parameters of heat treatment,including final temperature and heating rate,significantly affected the product morphologies.
CAI Ya NanWANG WuCHEN ZheYU Jian GangCHEN AQingZHU Kai Gui
