Surface characterization of chalcopyrite interacting with Leptospirillum ferriphilum

The alteration of surface properties of chalcopyrite after biological conditioning with Leptospirillum ferriphilum was studied by adsorption,zeta-potential,contact angle and bioleaching tests.The strains of L.ferriphilum cultured using different energy sources（either soluble ferrous ion or chalcopyrite） were used.The adhesion of bacteria to the chalcopyrite surface was a fast process.Additionally,the adsorption of substrate-grown bacteria was greater and faster than that of liquid-grown ones.The isoelectric point（IEP） of chalcopyrite moved toward that of pure L.ferriphilum after conditioning with bacteria.The chalcopyrite contact angle curves motioned diversely in the culture with or without energy source.The results of X-ray diffraction patterns（XRD）,scanning electron microscopy（SEM） and energy-dispersive X-ray spectroscopy（EDS） analysis indicate that the surface of chalcopyrite is covered with sulfur and jarosite during the bioleaching process by L.ferriphilum.Furthermore,EDS results imply that iron phase dissolves preferentially from chalcopyrite surface during bioleaching.The copper extraction is low,resulting from the formation of a passivation layer on the surface of chalcopyrite.The major component of the passivation layer that blocked continuous copper extraction is sulfur instead of jarosite.

3%碘酊治疗外阴尖锐湿疣76例

我院自1990～1996年门诊共收治女性生殖器尖锐湿疣76例。门诊采用3％碘酊局部涂擦治疗,随诊76例,仅1例复发,复发率为0.01％。 1 临床资料 本组76例均为门诊病人,年龄16～45岁,平均27±3.5岁,城市居民68例,占89.47％,农民8例,

Dual Manipulation of Ferromagnetism in Co-Doped ZnO Thin Films by Surfactant and n-Type Carriers

We present a conceptually-new approach “dual manipulation effect” using the surfactant passivation and the electron carrier doping for mediating intrinsic ferromagnetism in Codoped ZnO dilute magnetic semiconductor (DMS) thin films. The first-principles calculations show that the surface passivation by hydrogen serves as a magnetism switch for the Co-O-Co magnetic coupling at the surface of the thin film, and thus can control the spin polarization of the doped Co atoms. Meanwhile, the electron carrier doping can further function as an effective layerlike ferromagnetism mediator for the underneath layer. The dual manipulation effect sheds light on the essential magnetism origin of n-type Co:ZnO DMS thin films, and may be used as an alternative strategy for enhancing the ferromagnetism in other n-type DMS oxides thin films.

Chemical regulation of metal halide perovskite nanomaterials for efficient light-emitting diodes

Metal halide perovskite nanomaterials emerged as attractive emitting materials for light-emitting diodes(LEDs) devices due to their high photoluminescence quantum yield(PLQY), narrow bandwidth, high charge-carrier mobility, bandgap tunability, and facile synthesis. In the past few years, it has been witnessed an unprecedented advance in the field of metal halide perovskite nanomaterials based LEDs(Pe LEDs) with a rapid external quantum efficiency(EQE) increase from 0.1% to 14.36%. From the viewpoint of material chemistry, the chemical regulation of metal halide perovskite nanomaterials made a great contribution to the efficiency improvement of Pe LEDs. In this review, we categorize the strategies of chemical regulation as A-site cation engineering, B-site ion doping, X-site ion exchange, dimensional confinement, ligand exchange, surface passivation and interface optimization of transport layers for improving the EQEs of Pe LEDs. We also show the potentials of chemical regulation strategies to enhance the stability of Pe LEDs. Finally, we present insight toward future research directions and an outlook to further improve EQEs and stabilities of Pe LEDs aiming to practical applications.

Facial synthesis of highly stable and bright CsPbX(X=Cl,Br,I)perovskite nanocrystals via an anion exchange at the water-oil interface

Cesium lead halide perovskite nanocrystals(NCs)have attracted unprecedented attention owing to their compelling properties for optoelectronic applications.Compared with the classical hot-injection method,the roomtemperature(RT)synthetic strategy is more facile and tender,but it is hard to obtain stable CsPbI3 NCs and it usually uses polar solvents that sometimes reduce the stability and properties of NCs.Here,we reported a simple approach to synthesize highly efficient and stable CsPbI3 as well as other colortunable CsPbX3 NCs with high quantum efficiency at room temperature via an anion exchange at the water-oil interface,in which the as-synthesized pristine CsPbBr3 NCs in toluene were treated in aqueous solutions of HX(X=Cl,Br,and I)and protonated oleylamine(OAm)acted as a carrier.The synthesized CsPbI3 NCs had an emission at 680 nm and even showed excellent colloidal stability after being stored for 32 d.The high efficiency and stability of the obtained CsPbX3 NCs were ascribed to the facts that:(ⅰ)the polar reagents were almost removed from the surface of NCs;(ⅱ)the defect-related nonradiative recombination was suppressed efficiently by surface passivation.