Pure ZnO and Sn-doped ZnO thin films were successfully prepared by the spray pyrolysis method onto glass substrates. The obtained films were characterized by XRD （X-ray diffraction）, SEM （scanning electron microsc...Pure ZnO and Sn-doped ZnO thin films were successfully prepared by the spray pyrolysis method onto glass substrates. The obtained films were characterized by XRD （X-ray diffraction）, SEM （scanning electron microscopy） and ultraviolet-visible spectroscopy. The XRD results showed that the FWHM of Sn-doped ZnO film increased due to the substitution of Sn for Zn, the tin doping within the film causes the ZnO crystallinity to deteriorate. The grains of the film doped with Sn using dibutyltin diacetate were found to be non-uniform distribution through the sample but those appeared to form ganglia-like hills in the case of pure ZnO film. Furthermore, the Sn-doped ZnO films were tested with respect to the photocatalysis in aqueous solutions of MG （malachite green） upon UV-light illumination and in darkness. It was found that Sn-doped ZnO films prepared under specific conditions showed a lower photocatalytic activity than that of pure ZnO films.展开更多
The failure mode and adhesion of thermal barrier coating (TBC) 8YSZ (ZrO2+8% (w/w) Y2O3) deposited on NiCoCrAlTaY bond coat by atmospheric plasma spraying were investigated. A grooved modified three-point bending spec...The failure mode and adhesion of thermal barrier coating (TBC) 8YSZ (ZrO2+8% (w/w) Y2O3) deposited on NiCoCrAlTaY bond coat by atmospheric plasma spraying were investigated. A grooved modified three-point bending specimen that can generate a single interface crack to facilitate the control of crack growth was adopted for testing, which was conducted at the ambient temperature of 100 °C. The morphology and composition of fractured surfaces were examined by means of a scanning electron microscopy (SEM) and an energy disperse spectroscopy (EDS). Images and spectrum show that cracks are initiated and propagated exclusively within YSZ layer adjacent to top/bond coat interface. The load-displacement curves obtained exhibit similar shapes that indicate two distinct stages in crack initiation and stable crack growth. Finite element analyses were performed to extract the adhesion strength of the TBCs. The delamination toughness of the plasma-sprayed 8YSZ coatings at 100 °C, in terms of critical strain energy release rate Gc, can be reliably obtained from an analytical solution.展开更多
In this study,a jet cavitation device aimed at producing two-dimensional nanosheets was designed.The effects of cavitation generator type and jet pressure on the cavitation inception and intensity were examined by mon...In this study,a jet cavitation device aimed at producing two-dimensional nanosheets was designed.The effects of cavitation generator type and jet pressure on the cavitation inception and intensity were examined by monitoring the changes of sound pressure level(SPL).As such,the optimized cavitation generator with the best cavitation capability under the same ambient condition was determined.Further,BN and MoS 2,two kinds of layered materials,were exfoliated into individual flakes in aqueous solutions by this jet cavitation device.By investigating the morphology of these exfoliated flakes via scanning electron microscopy and transmission electron microscope,it was found that these pristine materials were mostly exfoliated into two-dimensional nanosheets,among which even monolayers were generally presented.This exfoliation process happened mainly due to the cavitation-induced intensive tensile stress acting on the layered materials.As graphene has been produced by this device successfully,it is anticipated that this jet cavitation device is suitable for producing other various two-dimensional nanosheets.展开更多
文摘Pure ZnO and Sn-doped ZnO thin films were successfully prepared by the spray pyrolysis method onto glass substrates. The obtained films were characterized by XRD （X-ray diffraction）, SEM （scanning electron microscopy） and ultraviolet-visible spectroscopy. The XRD results showed that the FWHM of Sn-doped ZnO film increased due to the substitution of Sn for Zn, the tin doping within the film causes the ZnO crystallinity to deteriorate. The grains of the film doped with Sn using dibutyltin diacetate were found to be non-uniform distribution through the sample but those appeared to form ganglia-like hills in the case of pure ZnO film. Furthermore, the Sn-doped ZnO films were tested with respect to the photocatalysis in aqueous solutions of MG （malachite green） upon UV-light illumination and in darkness. It was found that Sn-doped ZnO films prepared under specific conditions showed a lower photocatalytic activity than that of pure ZnO films.
基金Project (No 2007CB707702) supported by the National Basic Research Program (973) of China
文摘The failure mode and adhesion of thermal barrier coating (TBC) 8YSZ (ZrO2+8% (w/w) Y2O3) deposited on NiCoCrAlTaY bond coat by atmospheric plasma spraying were investigated. A grooved modified three-point bending specimen that can generate a single interface crack to facilitate the control of crack growth was adopted for testing, which was conducted at the ambient temperature of 100 °C. The morphology and composition of fractured surfaces were examined by means of a scanning electron microscopy (SEM) and an energy disperse spectroscopy (EDS). Images and spectrum show that cracks are initiated and propagated exclusively within YSZ layer adjacent to top/bond coat interface. The load-displacement curves obtained exhibit similar shapes that indicate two distinct stages in crack initiation and stable crack growth. Finite element analyses were performed to extract the adhesion strength of the TBCs. The delamination toughness of the plasma-sprayed 8YSZ coatings at 100 °C, in terms of critical strain energy release rate Gc, can be reliably obtained from an analytical solution.
基金supported by the Special Financial Support of Joint Building Project of the Beijing Education Committee
文摘In this study,a jet cavitation device aimed at producing two-dimensional nanosheets was designed.The effects of cavitation generator type and jet pressure on the cavitation inception and intensity were examined by monitoring the changes of sound pressure level(SPL).As such,the optimized cavitation generator with the best cavitation capability under the same ambient condition was determined.Further,BN and MoS 2,two kinds of layered materials,were exfoliated into individual flakes in aqueous solutions by this jet cavitation device.By investigating the morphology of these exfoliated flakes via scanning electron microscopy and transmission electron microscope,it was found that these pristine materials were mostly exfoliated into two-dimensional nanosheets,among which even monolayers were generally presented.This exfoliation process happened mainly due to the cavitation-induced intensive tensile stress acting on the layered materials.As graphene has been produced by this device successfully,it is anticipated that this jet cavitation device is suitable for producing other various two-dimensional nanosheets.
