Traditional stealth materials do not fulfill the requirements of high absorption for radar waves and low emissivity for infrared waves.Furthermore,they can be detected by various technologies,considerably threatening ...Traditional stealth materials do not fulfill the requirements of high absorption for radar waves and low emissivity for infrared waves.Furthermore,they can be detected by various technologies,considerably threatening weapon safety.Therefore,a stealth material compatible with radar and infrared was designed based on the photonic bandgap characteristics of photonic crystals.The radar stealth lay-er(bottom layer)is a composite of carbonyl iron/silicon dioxide/epoxy resin,and the infrared stealth layer(top layer)is a 1D photonic crystal with alternately and periodically stacked germanium and silicon nitride.Through composition optimization and structural adjust-ment,the effective absorption bandwidth of the compatible stealth material with a reflection loss of less than-10 dB has reached 4.95 GHz.The average infrared emissivity of the proposed design is 0.1063,indicating good stealth performance.The theoretical analysis proves that photonic crystals with this structural design can produce infrared waves within the photonic bandgap,achieving high radar wave transmittance and low infrared emissivity.Infrared stealth is achieved without affecting the absorption performance of the radar stealth layer,and the conflict between radar and infrared stealth performance is resolved.This work aims to promote the application of photonic crystals in compatible stealth materials and the development of stealth technology and to provide a design and theoretical found-ation for related experiments and research.展开更多
Turbojet engines played significant roles in the aviation industry and still have important applications in small engines for missiles to reduce weight.In this paper,we concentrate on the simulation of the centrifugal...Turbojet engines played significant roles in the aviation industry and still have important applications in small engines for missiles to reduce weight.In this paper,we concentrate on the simulation of the centrifugal turbine impeller and introduce the advanced Isogeometric analysis(IGA)method.IGA,which bypasses the mesh generation process in finite element analysis(FEA),has the potential for seamless integration between computer-aided design(CAD)and computer-aided engineering(CAE).To overcome the problem of only applying the spline basis function in IGA,we propose a parametric modeling approach and construct a centrifugal impeller library.The proposed modeling method generates a compatible hub by rotating the customized shaped blades,avoids the trimmed curves and surfaces,and provides suitable analysis models straight for IGA.The constructed library produces three distinct centrifugal impellers,which are represented by multiple nonuniform rational B-splines(NURBS)patches,including Reissner-Mindlin(RM)shell-to-RM shell,RM shell-to-solid,and solid-to-solid.To avoid the instability issues arising from weakly gluing algorithms in the analysis process on complex geometries,we propose an effective coupling method utilizing compatible patches to globally number the control points and assemble the stiffness matrix and load vector.The degree of freedom(DOF)of the solid is employed to dispose of the inconsistent DOF problem between the RM shell-to-solid model in this algorithm.We consider two kinds of operating environments,including centrifugal force and steady heat conduction to the functioning turboprop.Under the same accuracy,our MATLAB coding results demonstrate that IGA requires fewer elements,and achieves superior rendering effects to ABAQUS.Unlike FEA,the IGA method maintains the same geometry as the origin model after analysis.展开更多
Most multispectral compatible infrared camouflage devices primarily focus on achieving low emissivity but neglect environmental emissivity matching when environmental emissivity exceeds that of the devices,this create...Most multispectral compatible infrared camouflage devices primarily focus on achieving low emissivity but neglect environmental emissivity matching when environmental emissivity exceeds that of the devices,this creates a"low-emissivity exposure"risk.To address this issue,we develop a tunable multispectral compatible infrared camouflage device using phase change material In3SbTe2(IST).Simulation and experimental results demonstrate that in both the amorphous(aIST)and crystalline(cIST)states,the device achieves simulated plant infrared camouflage and ultra-low emissivity infrared camouflage within the atmospheric window bands(3–5μm and 8–14μm).To address thermal management,it utilizes two non-atmospheric window bands(2.5–3μm and 5–8μm)for heat dissipation.Additionally,laser stealth is realized at three specific wavelengths(1.064μm,1.55μm,and 10.6μm).In the visible spectrum,high absorptivity enables effective visible light camouflage.Adjusting the geometric parameters of top layer structure enables color variation.This work not only highlights potential applications in reversible switching,reconfigurable imaging,and dynamic coding using IST but also offers an effective strategy to counter multispectral detection technology.展开更多
This study is based on the background of the new era of innovation and inheritance in traditional Chinese medicine(TCM),with the fundamental goal of promoting the high-quality development of TCM.Guided by a deep under...This study is based on the background of the new era of innovation and inheritance in traditional Chinese medicine(TCM),with the fundamental goal of promoting the high-quality development of TCM.Guided by a deep understanding of General Secretary Xi Jinping's important discussions on TCM work,the study systematically investigates and analyzes the complementary advantages and collaborative innovation potential of apprenticeship education and university education.It focuses on the core proposition of‘dual-track integration‘,systematically explaining the internal mechanisms and pathways for the compatible development of the two educational models at both theoretical and practical levels.The research aims to provide theoretical support and practical reference for constructing a new mechanism for TCM talent training that meets the needs of the times。展开更多
Li-rich Mn-based oxides(LRMO)are of great significance in achieving high energy density all-solid-state lithium batteries(ASSLBs),owing to their high theoretical capacity and high operation voltage.Unfortunately,their...Li-rich Mn-based oxides(LRMO)are of great significance in achieving high energy density all-solid-state lithium batteries(ASSLBs),owing to their high theoretical capacity and high operation voltage.Unfortunately,their practical application is hindered by severe interface degradation due to the chemical oxidation and electrochemical decomposition of solid electrolytes(SEs),driven by high-active oxygen and electron sources from LRMO.Herein,an interfacial modification strategy is proposed to stabilize the surface lattice oxygen of LRMO and reduce electronic conduction between LRMO and SEs,synergistically.Accordingly,the byproducts from chemical oxidation(InO^(-))and electrochemical decomposition(LiCl^(-))are largely suppressed,leading to superior interfacial transport with the lowest resistance.Consequently,the ASSLB achieves a high reversible capacity of 227.9 mA h g^(-1)at 0.1 C,a cycling stability of 90.1%capacity retention after 200 cycles at 0.1 C,and a superior rate capability with a capacity of81.7 m A h g^(-1)at 3.0 C.This study enriches the fundamental understanding of LRMO/SEs interfacial evolution during the electrochemical cycling and the proposed interfacial modification strategy benefits the future design of Li-rich compounds for ASSLBs.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52071053,U1704253,and 52103334).
文摘Traditional stealth materials do not fulfill the requirements of high absorption for radar waves and low emissivity for infrared waves.Furthermore,they can be detected by various technologies,considerably threatening weapon safety.Therefore,a stealth material compatible with radar and infrared was designed based on the photonic bandgap characteristics of photonic crystals.The radar stealth lay-er(bottom layer)is a composite of carbonyl iron/silicon dioxide/epoxy resin,and the infrared stealth layer(top layer)is a 1D photonic crystal with alternately and periodically stacked germanium and silicon nitride.Through composition optimization and structural adjust-ment,the effective absorption bandwidth of the compatible stealth material with a reflection loss of less than-10 dB has reached 4.95 GHz.The average infrared emissivity of the proposed design is 0.1063,indicating good stealth performance.The theoretical analysis proves that photonic crystals with this structural design can produce infrared waves within the photonic bandgap,achieving high radar wave transmittance and low infrared emissivity.Infrared stealth is achieved without affecting the absorption performance of the radar stealth layer,and the conflict between radar and infrared stealth performance is resolved.This work aims to promote the application of photonic crystals in compatible stealth materials and the development of stealth technology and to provide a design and theoretical found-ation for related experiments and research.
基金supported by the Aeronautical Science Foundation of China(2023Z068051002)2021 Special Scientific Research on Civil Aircraft Projectthe Natural Science Foundation of China(52175213)。
文摘Turbojet engines played significant roles in the aviation industry and still have important applications in small engines for missiles to reduce weight.In this paper,we concentrate on the simulation of the centrifugal turbine impeller and introduce the advanced Isogeometric analysis(IGA)method.IGA,which bypasses the mesh generation process in finite element analysis(FEA),has the potential for seamless integration between computer-aided design(CAD)and computer-aided engineering(CAE).To overcome the problem of only applying the spline basis function in IGA,we propose a parametric modeling approach and construct a centrifugal impeller library.The proposed modeling method generates a compatible hub by rotating the customized shaped blades,avoids the trimmed curves and surfaces,and provides suitable analysis models straight for IGA.The constructed library produces three distinct centrifugal impellers,which are represented by multiple nonuniform rational B-splines(NURBS)patches,including Reissner-Mindlin(RM)shell-to-RM shell,RM shell-to-solid,and solid-to-solid.To avoid the instability issues arising from weakly gluing algorithms in the analysis process on complex geometries,we propose an effective coupling method utilizing compatible patches to globally number the control points and assemble the stiffness matrix and load vector.The degree of freedom(DOF)of the solid is employed to dispose of the inconsistent DOF problem between the RM shell-to-solid model in this algorithm.We consider two kinds of operating environments,including centrifugal force and steady heat conduction to the functioning turboprop.Under the same accuracy,our MATLAB coding results demonstrate that IGA requires fewer elements,and achieves superior rendering effects to ABAQUS.Unlike FEA,the IGA method maintains the same geometry as the origin model after analysis.
基金funded by the National Key R&D Program of China(2022YFF0706005)National Natural Science Foundation of China(12272407,62275269,62275271,62305387)+3 种基金Foundation of NUDT(ZK23-03)Hunan Provincial Natural Science Foundation of China(2022JJ40552,2023JJ40683)State Key Laboratory of High Performance Computing,NUDT(202201-12)the Hunan Provincial Innovation Foundation for Postgraduate,China(CX20230009).
文摘Most multispectral compatible infrared camouflage devices primarily focus on achieving low emissivity but neglect environmental emissivity matching when environmental emissivity exceeds that of the devices,this creates a"low-emissivity exposure"risk.To address this issue,we develop a tunable multispectral compatible infrared camouflage device using phase change material In3SbTe2(IST).Simulation and experimental results demonstrate that in both the amorphous(aIST)and crystalline(cIST)states,the device achieves simulated plant infrared camouflage and ultra-low emissivity infrared camouflage within the atmospheric window bands(3–5μm and 8–14μm).To address thermal management,it utilizes two non-atmospheric window bands(2.5–3μm and 5–8μm)for heat dissipation.Additionally,laser stealth is realized at three specific wavelengths(1.064μm,1.55μm,and 10.6μm).In the visible spectrum,high absorptivity enables effective visible light camouflage.Adjusting the geometric parameters of top layer structure enables color variation.This work not only highlights potential applications in reversible switching,reconfigurable imaging,and dynamic coding using IST but also offers an effective strategy to counter multispectral detection technology.
基金Yunnan Province High-level Science and Technology Talents and Innovation Team Selection Special Project(Project No.:202305AS350007)。
文摘This study is based on the background of the new era of innovation and inheritance in traditional Chinese medicine(TCM),with the fundamental goal of promoting the high-quality development of TCM.Guided by a deep understanding of General Secretary Xi Jinping's important discussions on TCM work,the study systematically investigates and analyzes the complementary advantages and collaborative innovation potential of apprenticeship education and university education.It focuses on the core proposition of‘dual-track integration‘,systematically explaining the internal mechanisms and pathways for the compatible development of the two educational models at both theoretical and practical levels.The research aims to provide theoretical support and practical reference for constructing a new mechanism for TCM talent training that meets the needs of the times。
基金supported by the National Natural Science Foundation of China with Grant No.12274176 and No.12474210supported by the relevant national program+1 种基金support from Department of Science and Technology of Jilin Province with Grant No.20210301021GXthe Fundamental Research Funds for the Center Universities with Grant No.2023-JCXK-03。
文摘Li-rich Mn-based oxides(LRMO)are of great significance in achieving high energy density all-solid-state lithium batteries(ASSLBs),owing to their high theoretical capacity and high operation voltage.Unfortunately,their practical application is hindered by severe interface degradation due to the chemical oxidation and electrochemical decomposition of solid electrolytes(SEs),driven by high-active oxygen and electron sources from LRMO.Herein,an interfacial modification strategy is proposed to stabilize the surface lattice oxygen of LRMO and reduce electronic conduction between LRMO and SEs,synergistically.Accordingly,the byproducts from chemical oxidation(InO^(-))and electrochemical decomposition(LiCl^(-))are largely suppressed,leading to superior interfacial transport with the lowest resistance.Consequently,the ASSLB achieves a high reversible capacity of 227.9 mA h g^(-1)at 0.1 C,a cycling stability of 90.1%capacity retention after 200 cycles at 0.1 C,and a superior rate capability with a capacity of81.7 m A h g^(-1)at 3.0 C.This study enriches the fundamental understanding of LRMO/SEs interfacial evolution during the electrochemical cycling and the proposed interfacial modification strategy benefits the future design of Li-rich compounds for ASSLBs.
