Using carbon nanotubes as nanobarriers,the growth of single-walled carbon nanotubes(SWNTs)on a quartz surface can be terminated.First,carbon nanotube nanobarriers were grown on a quartz surface by the gas ow-directed growth mode.Then,the SWNTs were grown on the quartz surface via the lattice-oriented growth mode,in which growth of SWNTs can be terminated by hitting the nanotube nanobarriers.Moreover,using the carbon nanotube nanobarrier as a marker,the mechanism of the growth of SWNTs on the quartz surface can be studied;a base-growth mechanism is indicated.Based on this termination process and the base-growth mechanism,SWNT arrays with controlled lengths can be grown on a quartz surface by xing the sites of bothcatalysts and nanobarriers.
Poly(acrylo-amidino ethylene amine) (PAEA) nanofiber membranes have been synthesized by combining the electrospinning technique and subsequent chemical modification. The membranes were used to remove As(V) from aqueous solution. The adsorption kinetics, equilibrium isotherms, and pH effect were investigated in batch experiments. The Langmuir isotherm and pseudo second-order kinetic models agree well with the experimental data. The PAEA nanofibers are effective for As(V) adsorption at pH 3. Experimental results showed that the maximum adsorption capacity of the PAEA nanofibers with As(V) is 76.92 mg g-1 , which is much higher than that of the PAEA microfibers (27.62 mg g-1 ). The adsorption rate of PAEA nanofibers is faster than that of PAEA microfibers due to its higher specific surface area. The PAEA nanofibers can be used as an effective adsorbent for the removal of As(V) in aqueous solution due to high adsorption capacity and short adsorption time to achieve equilibrium.
A single crystalline Mg2Si film was formed by solid phase reaction （SPR） of a Si（111） substrate with an Mg overlayer capped with an oxide layer（s）,which was enhanced by post annealing from room temperature to 100℃ in a molecular beam epitaxy （MBE） system.The thermal stability of the Mg2Si film was then systematically investigated by post annealing in an oxygen-radical ambient at 300℃,450℃ and 650℃,respectively.The Mg2Si film stayed stable until the annealing temperature reached 450℃ then it transformed into amorphous MgOx attributed to the decomposition of Mg2Si and the oxidization of dissociated Mg.
In the present work, post-annealing is adopted to investigate the formation and the correlation of Sb complexes and Zn interstitials in Sb-ion implanted ZnO films, by using Raman scattering technique and electrical characterizations. The damage of Zn sublattice, produced by ion bombardment process is discerned from the unrecovered E2 （L） peak in annealed high Sb＋ dose implanted samples. It is suggested that the Zn sublattice may be strongly affected by the introduction of Sb dopant because of the formation of Sbzn-2Vz,, complex acceptor. The appearance of a new peak at 510 cm-1 in the annealed high dose Sb＋ implanted samples is speculated to result from （Zn interstitials-O interstitials） Zni-Oi complex, which is in a good accordance with the electrical measurement. The p-type ZnO is difficult to obtain from the Sb＋ implantation, however, which can be realized by in-situ Sb doping with proper growth conditions instead.
