Biodegradable Zn alloys are a hot topic in the biodegradable vascular stent materials,the study on preparing Zn alloys microtubes for vascular stent is still insufficient and none of the tubes could well meet the mech...Biodegradable Zn alloys are a hot topic in the biodegradable vascular stent materials,the study on preparing Zn alloys microtubes for vascular stent is still insufficient and none of the tubes could well meet the mechanical requirement by present.In this study,we fabricate Zn-0.5Mn-0.05 Mg microtube with outer diameter of 3.5 mm and wall thickness of 0.2 mm by five passes three-roller rolling.The mechanical properties of the microtube are 277±2.9 MPa,330±3.3 MPa and 39.8±5.25%for the yield tensile strength(YTS),ultimate tensile strength(UTS)and break elongation,respectively,which well satisfies the requirements of the vascular stent.The leading factors to the variations of the mechanical property are texture evolution,grain size refinement and microstructure uniformity during the rolling process,and the main deformation mechanisms are twinning and dislocation movement.As a result of the dynamic recrystallization,the grain size decreases obviously and the microstructure gets more uniform as the rolling pass increases.The texture gradually changes from a basal texture<0110>‖ED(extrusion direction)for the as-extruded tube blank to deformation texture<0001>‖RD(rolling direction)and non-basal texture<0221>‖RD for the 5-pass rolled microtube.展开更多
Terahertz(THz)switches are essential components of THz communication systems.THz switches based on conventional waveguides and photonic crystal structures are sensitive to manufacturing defects and sharp bending,resul...Terahertz(THz)switches are essential components of THz communication systems.THz switches based on conventional waveguides and photonic crystal structures are sensitive to manufacturing defects and sharp bending,resulting in high scattering losses.In addition,THz switches with tunable working bandwidths have not yet been demonstrated.Here,we design THz switches based on a topological valley photonic crystal(VPC)structure using magnetic materials,which can achieve high forward transmittance based on the unique spin–valley locking effect.The broad working bandwidth allows selective turning on and off at a designed wavelength region by controlling the applied magnetic field.The designed THz switch can achieve an extinction ratio of up to 31.66 dB with an insertion loss of less than 0.13 dB.The 3-dB bandwidth is up to 49 GHz.This tunable THz switch can be experimentally fabricated by current fabrication techniques and thus can find broad applications in THz communication systems.展开更多
For all-optical communication and information processing,it is necessary to develop all-optical logic gates based on photonic structures that can directly perform logic operations.All-optical logic gates have been dem...For all-optical communication and information processing,it is necessary to develop all-optical logic gates based on photonic structures that can directly perform logic operations.All-optical logic gates have been demonstrated based on conventional waveguides and interferometry,as well as photonic crystal structures.Nonetheless,any defects in those structures will introduce high scattering loss,which compromises the fidelity and contrast ratio of the information process.Based on the spin-valley locking effect that can achieve defect-immune unidirectional transmission of topological edge states in valley photonic crystals(VPCs),we propose a high-performance all-optical logic OR gate based on a VPC structure.By tuning the working bandwidth of the two input channels,we prevent interference between the two channels to achieve a stable and high-fidelity output.The transmittance of both channels is higher than 0.8,and a high contrast ratio of 28.8 dB is achieved.Moreover,the chirality of the logic gate originated from the spin-valley locking effect allows using different circularly polarized light as inputs,representing“1”or“0”,which is highly desired in quantum computing.The device’s footprint is 18μm×12μm,allowing high-density on-chip integration.In addition,this design can be experimentally fabricated using current nanofabrication techniques and will have potential applications in optical communication,information processing,and quantum computing.展开更多
Dynamic visualization of multidimensional hydrometeorological data is vital for decision-makers to catch situational awareness and command an emergency response in natural disasters.Nevertheless,few software tools can...Dynamic visualization of multidimensional hydrometeorological data is vital for decision-makers to catch situational awareness and command an emergency response in natural disasters.Nevertheless,few software tools can comprehensively visualize hydrometeorological data in different scales,dimensions,and time.In this paper,an interactive 4D spatio-temporal visualization system based on a virtual globe is proposed.Voxel-based data model and multi-level index are adopted to organize the field data in a unified data structure.Meanwhile,it is resampled in both spatial and temporal dimensions in memory to prepare smooth data stream for rendering.Ten field models,including large-scale volume rendering and adaptive streamline rendering,are accelerated and integrated to display the field data collaboratively.The profile analysis and eddy tracking improve user experience in interactively exploring specific scenes.The system is tested against both large-scale meteorological data in the atmosphere and small-scale hydrological data at the surface,using typhoon landfall and riverine flood,respectively.The results demonstrate the applicability and efficiency of the system to dynamically visualize hydrometeorological data.展开更多
基金supported by the National Key Research and Development Program of China(2023YFB3812902)the Fundamental Research Funds for the Central Universities of China(N2302020).
文摘Biodegradable Zn alloys are a hot topic in the biodegradable vascular stent materials,the study on preparing Zn alloys microtubes for vascular stent is still insufficient and none of the tubes could well meet the mechanical requirement by present.In this study,we fabricate Zn-0.5Mn-0.05 Mg microtube with outer diameter of 3.5 mm and wall thickness of 0.2 mm by five passes three-roller rolling.The mechanical properties of the microtube are 277±2.9 MPa,330±3.3 MPa and 39.8±5.25%for the yield tensile strength(YTS),ultimate tensile strength(UTS)and break elongation,respectively,which well satisfies the requirements of the vascular stent.The leading factors to the variations of the mechanical property are texture evolution,grain size refinement and microstructure uniformity during the rolling process,and the main deformation mechanisms are twinning and dislocation movement.As a result of the dynamic recrystallization,the grain size decreases obviously and the microstructure gets more uniform as the rolling pass increases.The texture gradually changes from a basal texture<0110>‖ED(extrusion direction)for the as-extruded tube blank to deformation texture<0001>‖RD(rolling direction)and non-basal texture<0221>‖RD for the 5-pass rolled microtube.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1404201)Australia Research Council(Grant Nos.DP220100603 and FT220100559)+7 种基金the National Natural Science Foundation of China(Grant No.U23A20375)the Natural Science Foundation of Shanxi Province(Grant No.202403021211011)Research Project Supported by Shanxi Scholarship Council of China(Grant No.2024-032)Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province(Grant No.20240006)the Program of State Key Laboratory of Quantum Optics and Quantum Optics Devices(Grant No.KF202402)Basic Scientific Research Conditions and Major Scientific Instrument and Equipment Development of Anhui Science and Technology Department(Grant No.2023YFF0715700)Key Research Project of Shanxi Province(Grant No.202302150101001)Linkage Project Scheme(Grant Nos.LP210200345 and LP210100467).
文摘Terahertz(THz)switches are essential components of THz communication systems.THz switches based on conventional waveguides and photonic crystal structures are sensitive to manufacturing defects and sharp bending,resulting in high scattering losses.In addition,THz switches with tunable working bandwidths have not yet been demonstrated.Here,we design THz switches based on a topological valley photonic crystal(VPC)structure using magnetic materials,which can achieve high forward transmittance based on the unique spin–valley locking effect.The broad working bandwidth allows selective turning on and off at a designed wavelength region by controlling the applied magnetic field.The designed THz switch can achieve an extinction ratio of up to 31.66 dB with an insertion loss of less than 0.13 dB.The 3-dB bandwidth is up to 49 GHz.This tunable THz switch can be experimentally fabricated by current fabrication techniques and thus can find broad applications in THz communication systems.
基金Project supported by the National Key Research and Development Program of the Ministry of Science and Technology of China(Grant No.2022YFA1404201)the National Natural Science Foundation of China(Grant No.11904255)the Key Research and Development Program of Shanxi Province(International Cooperation)(Grant No.201903D421052).
文摘For all-optical communication and information processing,it is necessary to develop all-optical logic gates based on photonic structures that can directly perform logic operations.All-optical logic gates have been demonstrated based on conventional waveguides and interferometry,as well as photonic crystal structures.Nonetheless,any defects in those structures will introduce high scattering loss,which compromises the fidelity and contrast ratio of the information process.Based on the spin-valley locking effect that can achieve defect-immune unidirectional transmission of topological edge states in valley photonic crystals(VPCs),we propose a high-performance all-optical logic OR gate based on a VPC structure.By tuning the working bandwidth of the two input channels,we prevent interference between the two channels to achieve a stable and high-fidelity output.The transmittance of both channels is higher than 0.8,and a high contrast ratio of 28.8 dB is achieved.Moreover,the chirality of the logic gate originated from the spin-valley locking effect allows using different circularly polarized light as inputs,representing“1”or“0”,which is highly desired in quantum computing.The device’s footprint is 18μm×12μm,allowing high-density on-chip integration.In addition,this design can be experimentally fabricated using current nanofabrication techniques and will have potential applications in optical communication,information processing,and quantum computing.
基金National Natural Science Foundation of China:[Grant Number No.41722109,61825103,91738302]Major State Research Development Program of China:[Grant Number No.2017YFB0504103]+2 种基金Hubei Provincial Natural Science Foundation of China:[Grant Number No.2018CFA053]Natural Science Foundation Innovation Group Project of Hubei Province,China:[Grant Number No.2016CFA003]Wuhan Yellow Crane Talents(Science)Program:[Grant Number 2016].
文摘Dynamic visualization of multidimensional hydrometeorological data is vital for decision-makers to catch situational awareness and command an emergency response in natural disasters.Nevertheless,few software tools can comprehensively visualize hydrometeorological data in different scales,dimensions,and time.In this paper,an interactive 4D spatio-temporal visualization system based on a virtual globe is proposed.Voxel-based data model and multi-level index are adopted to organize the field data in a unified data structure.Meanwhile,it is resampled in both spatial and temporal dimensions in memory to prepare smooth data stream for rendering.Ten field models,including large-scale volume rendering and adaptive streamline rendering,are accelerated and integrated to display the field data collaboratively.The profile analysis and eddy tracking improve user experience in interactively exploring specific scenes.The system is tested against both large-scale meteorological data in the atmosphere and small-scale hydrological data at the surface,using typhoon landfall and riverine flood,respectively.The results demonstrate the applicability and efficiency of the system to dynamically visualize hydrometeorological data.
