This paper proposes a new technique which introduces the high-order single-step-β method(HSM)into the experimental study on the substructure pseudo-dynamic testing(SPDT).The technique is based on the proposed concept...This paper proposes a new technique which introduces the high-order single-step-β method(HSM)into the experimental study on the substructure pseudo-dynamic testing(SPDT).The technique is based on the proposed concept of equivalent shear stiffness which can meet the requirement of the HSM algorithm.A study is done to theoretically validate the technique by the numerical analysis of two-storey shear building structure,in comparison of the proposed substructure pseudo-dynamic testing algorithm with the central difference method(CDM).Then,a full-scale SPDT model,the three-storey frame-supported reinforced concrete short-limb masonry shear wall structure,is designed and tested to simulate the seismic response of the corresponding six-storey structure and verify the proposed force control HSM technique.Meanwhile,the techniques of both stiffness correction and force control are suggested to control algorithmic error,control error and measurement error.The results indicate that the force control HSM can be used in the full-scale multi-degree-of-freedom(MDOF)substructure pseudo-dynamic testing before descent segment of structure restoring force properties.展开更多
Graphitic carbon nitride(g-C_(3)N_(4))-based materials are regarded as one of the most potential photocatalysts for utilizing solar energy.In this work,we reported a facile one step in-situ hydrothermal-roasting metho...Graphitic carbon nitride(g-C_(3)N_(4))-based materials are regarded as one of the most potential photocatalysts for utilizing solar energy.In this work,we reported a facile one step in-situ hydrothermal-roasting method for preparing honeycomb-like g-C_(3)N_(4)/CeO_(2) nanosheets with abundant oxygen vacancies(g-C_(3)N_(4)/CeO_(2)-x).The hydrothermal-roasting and incomplete-sealed state can(i)generate an in-situ reducing atmosphere(CO,N2,NH3) to tune the concentration of oxygen vacancies in CeO_(2);(ii) beneficial to prevent continuous growth of g-C_(3)N_(4) and results in honeycomb-like g-C_(3)N_(4)/CeO_(2)-x hybrid nanosheets.What is more,the g-C_(3)N_(4)/CeO_(2)-x photocatalyst exhibited extended photoresponse range,increased specific surface area and obviously enhanced separation efficiency of photogenerated electron-hole pairs.As a proof-of-concept application,the optimized g-C_(3)N_(4)/CeO_(2)-xnanosheets could achieve 98% removal efficiency for Cr(Ⅵ) under visible light irradiation(λ≥420 nm)within 2.5 h,which is significantly better than those of pure g-C_(3)N_(4) and CeO_(2).This work provides a new idea for more rationally designing and constructing g-C_(3)N_(4)-based catalysts for efficient extended photochemical application.展开更多
Abstract： Undoped and doped KC1 single crystals have been successfully elaborated via the Czochralski （Cz） method. The effects of dopant Sb2O3 nanocrystals on structural and optical properties were investigated by ...Abstract： Undoped and doped KC1 single crystals have been successfully elaborated via the Czochralski （Cz） method. The effects of dopant Sb2O3 nanocrystals on structural and optical properties were investigated by a number of techniques, including X-ray diffraction （XRD）, scanning electron microscopy （SEM）, energy disper- sive X-ray （EDAX） analysis, UV-visible and photoluminescence （PL） spectrophotometers. An XRD pattern of KCI：Sb2O3 reveals that the Sb2O3 nanocrystals are in the well-crystalline orthorhombic phase. The broadening of diffraction peaks indicated the presence of a Sb2O3 semiconductor in the nanometer size regime. The shift of ab- sorption and PL peaks is observed near 334 nm and 360 nm respectively due to the quantum confinement effect in Sb2O3 nanocrystals. Particle sizes calculated from XRD studies agree fairly well with those estimated from optical studies. An SEM image of the surface KCI：Sb2O3 single crystal shows large quasi-spherical of Sb2O3 crystallites scattered on the surface. The elemental analysis from EDAX demonstrates that the KCI：Sb2O3 single crystal is slightly rich in oxygen and a source of excessive quantities of oxygen is discussed.展开更多
Crystallographic texture control is a major challenge in directionally solidified multiphase eutectic ceramics with complex faceted growth characteristics.In this study,the Czochralski(CZ)technique is proposed to prep...Crystallographic texture control is a major challenge in directionally solidified multiphase eutectic ceramics with complex faceted growth characteristics.In this study,the Czochralski(CZ)technique is proposed to prepare eutectic single crystal ceramic with large size(30 mm×125 mm).A highly oriented and unique texture of Al_(2)O_(3)/Y_(3)Al_(5)O_(12)(YAG)eutectic ceramic is formed via the 112¯0Al_(2)O_(3) single crystal seed induction based on crystallographic orientation tailoring.The orientations of Al_(2)O_(3)/YAG eutectic are more strictly constrained by single crystal seed induction on the basis of the minimum interface energy principle,resulting in a defined single orientation relationship along the solidification direction.In particular,the single crystallographic orientation can be obtained in a short competitive solidification distance under the influence of epitaxial solidification from single crystal seed.Therefore,it has been confirmed that the orientations of 112¯0Al_(2)O_(3) and 111YAG are preferentially stabilized with the minimum under-cooling during directional solidification.Crystallographic orientation disturbances and instabilities due to polycrystalline crystal seed are avoided.Finally,the successful texture control inducted by 112¯0Al_(2)O_(3) single crystal seed can provide a promising orientation design pathway for faced oxide eutectic solidification.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.50508012)
文摘This paper proposes a new technique which introduces the high-order single-step-β method(HSM)into the experimental study on the substructure pseudo-dynamic testing(SPDT).The technique is based on the proposed concept of equivalent shear stiffness which can meet the requirement of the HSM algorithm.A study is done to theoretically validate the technique by the numerical analysis of two-storey shear building structure,in comparison of the proposed substructure pseudo-dynamic testing algorithm with the central difference method(CDM).Then,a full-scale SPDT model,the three-storey frame-supported reinforced concrete short-limb masonry shear wall structure,is designed and tested to simulate the seismic response of the corresponding six-storey structure and verify the proposed force control HSM technique.Meanwhile,the techniques of both stiffness correction and force control are suggested to control algorithmic error,control error and measurement error.The results indicate that the force control HSM can be used in the full-scale multi-degree-of-freedom(MDOF)substructure pseudo-dynamic testing before descent segment of structure restoring force properties.
基金the National Natural Science Foundation of China(Nos.21103024,61171008)Natural Science Foundation of Zhejiang Province(No.LY19B060006)+1 种基金National Key Research and Development Program of China(No.2018YFB1502900)Technology Development Project of Jiaxing University(No.70518047)。
文摘Graphitic carbon nitride(g-C_(3)N_(4))-based materials are regarded as one of the most potential photocatalysts for utilizing solar energy.In this work,we reported a facile one step in-situ hydrothermal-roasting method for preparing honeycomb-like g-C_(3)N_(4)/CeO_(2) nanosheets with abundant oxygen vacancies(g-C_(3)N_(4)/CeO_(2)-x).The hydrothermal-roasting and incomplete-sealed state can(i)generate an in-situ reducing atmosphere(CO,N2,NH3) to tune the concentration of oxygen vacancies in CeO_(2);(ii) beneficial to prevent continuous growth of g-C_(3)N_(4) and results in honeycomb-like g-C_(3)N_(4)/CeO_(2)-x hybrid nanosheets.What is more,the g-C_(3)N_(4)/CeO_(2)-x photocatalyst exhibited extended photoresponse range,increased specific surface area and obviously enhanced separation efficiency of photogenerated electron-hole pairs.As a proof-of-concept application,the optimized g-C_(3)N_(4)/CeO_(2)-xnanosheets could achieve 98% removal efficiency for Cr(Ⅵ) under visible light irradiation(λ≥420 nm)within 2.5 h,which is significantly better than those of pure g-C_(3)N_(4) and CeO_(2).This work provides a new idea for more rationally designing and constructing g-C_(3)N_(4)-based catalysts for efficient extended photochemical application.
基金Project supported by the Crystallography Laboratory of the University of Constantine,Algeria
文摘Abstract： Undoped and doped KC1 single crystals have been successfully elaborated via the Czochralski （Cz） method. The effects of dopant Sb2O3 nanocrystals on structural and optical properties were investigated by a number of techniques, including X-ray diffraction （XRD）, scanning electron microscopy （SEM）, energy disper- sive X-ray （EDAX） analysis, UV-visible and photoluminescence （PL） spectrophotometers. An XRD pattern of KCI：Sb2O3 reveals that the Sb2O3 nanocrystals are in the well-crystalline orthorhombic phase. The broadening of diffraction peaks indicated the presence of a Sb2O3 semiconductor in the nanometer size regime. The shift of ab- sorption and PL peaks is observed near 334 nm and 360 nm respectively due to the quantum confinement effect in Sb2O3 nanocrystals. Particle sizes calculated from XRD studies agree fairly well with those estimated from optical studies. An SEM image of the surface KCI：Sb2O3 single crystal shows large quasi-spherical of Sb2O3 crystallites scattered on the surface. The elemental analysis from EDAX demonstrates that the KCI：Sb2O3 single crystal is slightly rich in oxygen and a source of excessive quantities of oxygen is discussed.
基金supported by the National Natural Science Foundation of China(Nos.52130204,52174376 and 51822405)the Guangdong Basic and Applied Basic Research Foundation(No.21201910250000848)+4 种基金the Science and Technology Innovation Team Plan of Shaan Xi Province(No.2021TD-17)the Joint Research Funds of the Department of Science&Technology of Shaanxi Province and NPU(No.2020GXLH-Z-024)The Youth Innovation Team of Shaanxi Universities,the Key R&D Program of Shaanxi Province(No.2019ZDLGY 04-04)the Fundamental Research Funds for the Central Universities(No.D5000210902)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(Nos.CX2021056,CX2021066 and CX2022033),China.
文摘Crystallographic texture control is a major challenge in directionally solidified multiphase eutectic ceramics with complex faceted growth characteristics.In this study,the Czochralski(CZ)technique is proposed to prepare eutectic single crystal ceramic with large size(30 mm×125 mm).A highly oriented and unique texture of Al_(2)O_(3)/Y_(3)Al_(5)O_(12)(YAG)eutectic ceramic is formed via the 112¯0Al_(2)O_(3) single crystal seed induction based on crystallographic orientation tailoring.The orientations of Al_(2)O_(3)/YAG eutectic are more strictly constrained by single crystal seed induction on the basis of the minimum interface energy principle,resulting in a defined single orientation relationship along the solidification direction.In particular,the single crystallographic orientation can be obtained in a short competitive solidification distance under the influence of epitaxial solidification from single crystal seed.Therefore,it has been confirmed that the orientations of 112¯0Al_(2)O_(3) and 111YAG are preferentially stabilized with the minimum under-cooling during directional solidification.Crystallographic orientation disturbances and instabilities due to polycrystalline crystal seed are avoided.Finally,the successful texture control inducted by 112¯0Al_(2)O_(3) single crystal seed can provide a promising orientation design pathway for faced oxide eutectic solidification.
