Density functional theory(DFT)calculations have been performed on 1 to 9 layers of Cu_(2)O(100),(111),and(110)planes to further understand the electronic band structures and the origin of the facet-dependent propertie...Density functional theory(DFT)calculations have been performed on 1 to 9 layers of Cu_(2)O(100),(111),and(110)planes to further understand the electronic band structures and the origin of the facet-dependent properties of Cu_(2)O crystals.The(100)planes show an invariant band structure with a constant band gap of 1.787 eV like that of a primitive cell.The(111)planes present a periodicity of every three layers with band gaps varying between zero and 1.787 eV.An unusual periodicity of every two layers has been found for the(110)planes oscillating between 1.787 eV and very small band gaps including a zero band gap.By comparing the valence band edges of different plane layers and the position of the Fermi level in the density of states(DOS)diagrams,relative valence band bending of the Cu_(2)O{100},{111},and{110}surfaces can be drawn to explain their strongly facet-dependent electrical conductivity properties.Moreover,while the(100)planes show a fixed crystal lattice with a tunable number of planes,the calculations identify slight bond length deviations and bond distortion for the(111)and(110)planes.The partial density of states(PDOS)diagrams also reveal(111)and(110)plane layer-dependent variations in the frontier orbital electron energy distribution.The structural perturbations at crystal surfaces can yield different barrier heights to charge transport across the{100},{111},and{110}faces,and photons of different wavelengths should get absorbed in the thin surface layer to produce the observed optical facet effects.Such lattice perturbations should be present in other semiconductor materials as surface-dependent behaviors are broadly observable in many semiconductors.展开更多
The frequent failures of small-diameter vascular grafts(SDVGs)mainly result from thrombosis and insufficient endothelialization.Despite recent biochemical modification strategies aiming to enhance long-term patency,th...The frequent failures of small-diameter vascular grafts(SDVGs)mainly result from thrombosis and insufficient endothelialization.Despite recent biochemical modification strategies aiming to enhance long-term patency,the challenges of suppressing thrombosis and promoting rapid endothelialization persist.We thus designed a biomimetic three-layer flexible vascular graft scaffold.This scaffold precisely replicates the nonlinear mechanical responses of vascular tissues and promotes vascular regeneration by minimizing the mechanical mismatch between the graft and the host.The biomimetic flexible SDVG scaffold comprises a screwed inner layer,a middle fabric layer,and a Polyethylene terephthalate(PET)helical coil.It shows excellent bending resistance and resilience,reducing thrombosis formation caused by impaired blood flow during bending.Moreover,this scaffold notably improves the adhesion,spreading,proliferation,and elongation of endothelial cells,facilitating luminal remodeling and maintaining long-term patency through its intimal topography.In vivo studies demonstrate that the endothelial layer forms within three months of implantation,ensuring long-term patency.By three months after implantation,both the endothelial and smooth muscle layers are regenerated,developing hierarchical microstructures and compositions similar to those of native vessels.The biomimetic flexible vascular graft with screwed structures exhibits excellent bending resistance and enhanced vascular remodeling,thereby promoting blood vessel regeneration and showing strong potential for clinical translation.展开更多
At present,smart substations use the IEC61850 standard based on the architectural framework of three layers and two networks to realize information digitization and advanced applications.Although the smart substation ...At present,smart substations use the IEC61850 standard based on the architectural framework of three layers and two networks to realize information digitization and advanced applications.Although the smart substation offers many improvements in design,equipment manufacturing,and construction,the intelligent devices used in smart substations are costly,and are also difficult to maintain since they are dispersed within a single unit.Functionality optimization and device integration,thus,have become important issues in smart substation development.This paper presents an integrated solution and implementation process for a smart substation system.In the process layer,an integrated intelligence component is developed that functions both as an intelligent terminal and a merging unit.In the bay layer,an integrated station-area protection measurement and control master device is designed to achieve such functions as protection,monitoring,control,fault recorder,and power quality monitoring.Finally,in the station control layer,an integrated information platform is established to bring together various system functions and to promote interactive sharing.Integration technology improves the economy and practicality of the smart substation,especially in a distribution power grid.展开更多
文摘Density functional theory(DFT)calculations have been performed on 1 to 9 layers of Cu_(2)O(100),(111),and(110)planes to further understand the electronic band structures and the origin of the facet-dependent properties of Cu_(2)O crystals.The(100)planes show an invariant band structure with a constant band gap of 1.787 eV like that of a primitive cell.The(111)planes present a periodicity of every three layers with band gaps varying between zero and 1.787 eV.An unusual periodicity of every two layers has been found for the(110)planes oscillating between 1.787 eV and very small band gaps including a zero band gap.By comparing the valence band edges of different plane layers and the position of the Fermi level in the density of states(DOS)diagrams,relative valence band bending of the Cu_(2)O{100},{111},and{110}surfaces can be drawn to explain their strongly facet-dependent electrical conductivity properties.Moreover,while the(100)planes show a fixed crystal lattice with a tunable number of planes,the calculations identify slight bond length deviations and bond distortion for the(111)and(110)planes.The partial density of states(PDOS)diagrams also reveal(111)and(110)plane layer-dependent variations in the frontier orbital electron energy distribution.The structural perturbations at crystal surfaces can yield different barrier heights to charge transport across the{100},{111},and{110}faces,and photons of different wavelengths should get absorbed in the thin surface layer to produce the observed optical facet effects.Such lattice perturbations should be present in other semiconductor materials as surface-dependent behaviors are broadly observable in many semiconductors.
基金supported by the National Key Research and Development Program of China(No.2023YFC2412402)the Key Research and Development Program of Hubei Province(No.2022ACA002).
文摘The frequent failures of small-diameter vascular grafts(SDVGs)mainly result from thrombosis and insufficient endothelialization.Despite recent biochemical modification strategies aiming to enhance long-term patency,the challenges of suppressing thrombosis and promoting rapid endothelialization persist.We thus designed a biomimetic three-layer flexible vascular graft scaffold.This scaffold precisely replicates the nonlinear mechanical responses of vascular tissues and promotes vascular regeneration by minimizing the mechanical mismatch between the graft and the host.The biomimetic flexible SDVG scaffold comprises a screwed inner layer,a middle fabric layer,and a Polyethylene terephthalate(PET)helical coil.It shows excellent bending resistance and resilience,reducing thrombosis formation caused by impaired blood flow during bending.Moreover,this scaffold notably improves the adhesion,spreading,proliferation,and elongation of endothelial cells,facilitating luminal remodeling and maintaining long-term patency through its intimal topography.In vivo studies demonstrate that the endothelial layer forms within three months of implantation,ensuring long-term patency.By three months after implantation,both the endothelial and smooth muscle layers are regenerated,developing hierarchical microstructures and compositions similar to those of native vessels.The biomimetic flexible vascular graft with screwed structures exhibits excellent bending resistance and enhanced vascular remodeling,thereby promoting blood vessel regeneration and showing strong potential for clinical translation.
基金supported in part by the research program of State Grid Corporation of China under Grant PD71-15-036.
文摘At present,smart substations use the IEC61850 standard based on the architectural framework of three layers and two networks to realize information digitization and advanced applications.Although the smart substation offers many improvements in design,equipment manufacturing,and construction,the intelligent devices used in smart substations are costly,and are also difficult to maintain since they are dispersed within a single unit.Functionality optimization and device integration,thus,have become important issues in smart substation development.This paper presents an integrated solution and implementation process for a smart substation system.In the process layer,an integrated intelligence component is developed that functions both as an intelligent terminal and a merging unit.In the bay layer,an integrated station-area protection measurement and control master device is designed to achieve such functions as protection,monitoring,control,fault recorder,and power quality monitoring.Finally,in the station control layer,an integrated information platform is established to bring together various system functions and to promote interactive sharing.Integration technology improves the economy and practicality of the smart substation,especially in a distribution power grid.
