Efficiency and emissions of spark-ignited engines are significantly affected by combustion phase which can usually be indicated by crank angle of 50% mass burnt （CA50）. Managing combustion phase at the optimal value...Efficiency and emissions of spark-ignited engines are significantly affected by combustion phase which can usually be indicated by crank angle of 50% mass burnt （CA50）. Managing combustion phase at the optimal value at which the maximal efficiency can be achieved is a challenging issue due to the cyclic variations of combustion process. This paper addresses this issue in two loops： CA50 set-point optimization （outer loop） and set-point tracking （inner loop） by controlling spark advance （SA）. Extremum seeking approach maximizing thermal efficiency is employed in the CA50 set-point optimization. A proportional- integral （PI） controller is adopted to make the moving average value of CA50 tracking the optimal CA50 set-point determined in the outer loop. Moreover, in order to obtain fast responses at steady and transient operations, feed-forward maps are designed for extremum seeking controller and PI controller, respectively. Finally, experimental validations are conducted on a six-cylinder gasoline at steady and transient operations to show the effectiveness of proposed control scheme.展开更多
In this paper, a new partial transmit sequence（PTS）scheme with low computational complexity is proposed for the problems of high computational complexity in the conventional PTS method. By analyzing the relationship...In this paper, a new partial transmit sequence（PTS）scheme with low computational complexity is proposed for the problems of high computational complexity in the conventional PTS method. By analyzing the relationship of candidate sequences in the PTS method under the interleaved partition method, it has been discovered that some candidate sequences generated by phase factor sequences have the same peak average power ratio（PAPR）. Hence, phase factor sequences can be optimized to reduce their searching times. Then, the computational process of generating candidate sequences can be simplified by improving the utilization of data and minimizing the calculations of complex multiplication. The performance analysis shows that, compared with the conventional PTS scheme, the proposed approach significantly decreases the computational complexity and has no loss of PAPR performance.展开更多
Revised phase diagram of the CeO2-ZrO2 system is optimized and the lattice stability parameters of CeO2 of various phases as well as solution parameters of phases (liquid, cubic, tetragonal and monoclinic) are simulta...Revised phase diagram of the CeO2-ZrO2 system is optimized and the lattice stability parameters of CeO2 of various phases as well as solution parameters of phases (liquid, cubic, tetragonal and monoclinic) are simultaneously obtained by using the Kaufman and Nesor's model for describing the ceramic solutions and the Lukas program展开更多
In this paper a critical assessment and optimization of the phase diagrams and thermodynamic properties of the PrCl_3-MCl(M=Li,Na)and PrCl_3-MCl_2(M=Mg,Ca,Sr,Ba) binary systems have been per- formed.The assessed and o...In this paper a critical assessment and optimization of the phase diagrams and thermodynamic properties of the PrCl_3-MCl(M=Li,Na)and PrCl_3-MCl_2(M=Mg,Ca,Sr,Ba) binary systems have been per- formed.The assessed and optimized binary phase diagrams and thermodynamic data with self consistency are a better basis for constructing multicomponent phase diagrams.展开更多
All-small-molecule organic solar cells(ASM OSCs)have emerged as promising photovoltaic technologies due to their excellent batch-to-batch reproducibility and potential for scalable manufacturing.However,the developmen...All-small-molecule organic solar cells(ASM OSCs)have emerged as promising photovoltaic technologies due to their excellent batch-to-batch reproducibility and potential for scalable manufacturing.However,the development of eco-friendly processing protocols using halogen-free solvents combined with sustainable solid additives remains unexplored,despite being crucial for realizing green and efficient ASM OSC production.Herein,we demonstrate the first successful integration of plant-extracted apigenin(AP)as a green solid additive with tetrahydrofuran(THF),a non-halogenated processing solvent,in ASM OSC fabrication.Systematic investigations reveal that AP establishes hydrogen-bonding interactions with the acceptor molecules,thereby promoting tighter molecular packing and enhancing crystallinity.Simultaneously,the additive modulates donor-acceptor miscibility to optimize phase-separated domain sizes.These synergistic effects generate a well-interconnected nanomorphology with balanced charge transport pathways,effectively facilitating exciton dissociation while suppressing charge recombination.The resultant devices obtain a remarkable power conversion efficiency(PCE)of 14.51%,representing one of the highest performances among halogen-free processed binary ASM OSCs reported to date.This pioneering work establishes a viable pathway toward sustainable OSC manufacturing by demonstrating that eco-friendly additives can synergistically cooperate with non-ha logenated solvents to simultaneously enhance device performance and process sustainability.展开更多
Aberration-corrected focus scanning is crucial for high-precision optics,but the conventional optical systems rely on bulky and complicated dynamic correctors.Recently,Shiyi Xiao's group proposed a method using tw...Aberration-corrected focus scanning is crucial for high-precision optics,but the conventional optical systems rely on bulky and complicated dynamic correctors.Recently,Shiyi Xiao's group proposed a method using two rotating cascaded transmissive metasurfaces for adaptive aberration correction in focus scanning.The optimized phase profiles enable precise control of the focal position for scanning custom-curved surfaces.This concept was experimentally validated by two allsilicon meta-devices in the terahertz regime,paving the way for high-precision and compact optical devices in various applications.展开更多
In the past two decades,extensive and in-depth research has been conducted on Time Series InSAR technology with the advancement of high-performance SAR satellites and the accumulation of big SAR data.The introduction ...In the past two decades,extensive and in-depth research has been conducted on Time Series InSAR technology with the advancement of high-performance SAR satellites and the accumulation of big SAR data.The introduction of distributed scatterers in Distributed Scatterers InSAR(DS-InSAR)has significantly expanded the application scenarios of InSAR geodetic measurement by increasing the number of measurement points.This study traces the history of DS-InSAR,presents the definition and characteristics of distributed scatterers,and focuses on exploring the relationships and distinctions among proposed algorithms in two crucial steps:statistically homogeneous pixel selection and phase optimization.Additionally,the latest research progress in this field is tracked and the possible development direction in the future is discussed.Through simulation experiments and two real InSAR case studies,the proposed algorithms are compared and verified,and the advantages of DS-InSAR in deformation measurement practice are demonstrated.This work not only offers insights into current trends and focal points for theoretical research on DS-InSAR but also provides practical cases and guidance for applied research.展开更多
Vanadium-based electrodes are regarded as attractive cathode materials in aqueous zinc ion batteries(ZIBs)caused by their high capacity and unique layered structure.However,it is extremely challenging to acquire high ...Vanadium-based electrodes are regarded as attractive cathode materials in aqueous zinc ion batteries(ZIBs)caused by their high capacity and unique layered structure.However,it is extremely challenging to acquire high electrochemical performance owing to the limited electronic conductivity,sluggish ion kinetics,and severe volume expansion during the insertion/extraction process of Zn^(2+).Herein,a series of V_(2)O_(3)nanospheres embedded N-doped carbon nanofiber structures with various V_(2)O_(3)spherical morphologies(solid,core-shell,hollow)have been designed for the first time by an electrospinning technique followed thermal treatments.The N-doped carbon nanofibers not only improve the electrical conductivity and the structural stability,but also provides encapsulating shells to prevent the vanadium dissolution and aggregation of V_(2)O_(3)particles.Furthermore,the varied morphological structures of V_(2)O_(3)with abundant oxygen vacancies can alleviate the volume change and increase the Zn^(2+)pathway.Besides,the phase transition between V_(2)O_(3)and Zn_XV_(2)O_(5-m)·n H_(2)O in the cycling was also certified.As a result,the as-obtained composite delivers excellent long-term cycle stability and enhanced rate performance for coin cells,which is also confirmed through density functional theory(DFT)calculations.Even assembled into flexible ZIBs,the sample still exhibits superior electrochemical performance,which may afford new design concept for flexible cathode materials of ZIBs.展开更多
This paper investigates an unmanned aerial vehicle(UAV)-assisted multi-object offloading scheme for blockchain-enabled Vehicle-to-Everything(V2X)systems.Due to the presence of an eavesdropper(Eve),the system’s com-mu...This paper investigates an unmanned aerial vehicle(UAV)-assisted multi-object offloading scheme for blockchain-enabled Vehicle-to-Everything(V2X)systems.Due to the presence of an eavesdropper(Eve),the system’s com-munication links may be insecure.This paper proposes deploying an intelligent reflecting surface(IRS)on the UAV to enhance the communication performance of mobile vehicles,improve system flexibility,and alleviate eavesdropping on communication links.The links for uploading task data from vehicles to a base station(BS)are protected by IRS-assisted physical layer security(PLS).Upon receiving task data,the computing resources provided by the edge computing servers(MEC)are allocated to vehicles for task execution.Existing blockchain-based computation offloading schemes typically focus on improving network performance,such as minimizing energy consumption or latency,while neglecting the Gas fees for computation offloading and the costs required for MEC computation,leading to an imbalance between service fees and resource allocation.This paper uses a utility-oriented computation offloading scheme to balance costs and resources.This paper proposes alternating phase optimization and power optimization to optimize the energy consumption,latency,and communication secrecy rate,thereby maximizing the weighted total utility of the system.Simulation results demonstrate a notable enhancement in the weighted total system utility and resource utilization,thereby corroborating the viability of our approach for practical applications.展开更多
The flexibility of unmanned aerial vehicles(UAVs)allows them to be quickly deployed to support ground users.Intelligent reflecting surface(IRS)can reflect the incident signal and form passive beamforming to enhance th...The flexibility of unmanned aerial vehicles(UAVs)allows them to be quickly deployed to support ground users.Intelligent reflecting surface(IRS)can reflect the incident signal and form passive beamforming to enhance the signal in the specific direction.Motivated by the promising benefits of both technologies,we consider a new scenario in this paper where a UAV uses non-orthogonal multiple access to serve multiple users with IRS.According to their distance to the UAV,the users are divided into the close users and remote users.The UAV hovers above the close users due to their higher rate requirement,while the IRS is deployed near the remote users to enhance their received power.We aim at minimizing the transmit power of UAV by jointly optimizing the beamforming of UAV and the phase shift of IRS while ensuring the decoding requirement.However,the problem is non-convex.Therefore,we decompose it into two sub-problems,including the transmit beamforming optimization and phase shift optimization,which are transformed into second-order cone programming and semidefinite programming,respectively.We propose an iterative algorithm to solve the two sub-problems alternatively.Simulation results prove the effectiveness of the proposed scheme in minimizing the transmit power of UAV.展开更多
This paper considers a high energy efficiency dynamic connected(HEDC)structure,which promotes the practicability and reduces the power consumption of hybrid precoding system by lowresolution phase shifters(PSs).Based ...This paper considers a high energy efficiency dynamic connected(HEDC)structure,which promotes the practicability and reduces the power consumption of hybrid precoding system by lowresolution phase shifters(PSs).Based on the proposed structure,a new hybrid precoding algorithm is presented to optimize the energy efficiency,namely,HP-HEDC algorithm.Firstly,via a new defined effective optimal precoding matrix,the problem of optimizing the analog switch precoding matrix is formulated as a sparse representation problem.Thus,the optimal analog switch precoding matrix can be readily obtained by the branch-and-bound method.Then,the digital precoding matrix optimization problem is modeled as a dictionary update problem and solved by the method of optimal direction(MOD).Finally,the diagonal entries of the analog PS precoding matrix are optimized by exhaustive search independently since PS and antenna is one-to-one.Simulation results show that the HEDC structure enjoys low power consumption and satisfactory spectral efficiency.The proposed algorithm presents at least 50%energy efficiency improvement compared with other algorithms when the PS resolution is set as 3-bit.展开更多
Waste water treatment process(WWTP)control has been attracting more and more attention.However,various undesired factors,such as disturbance,uncertainties,and strong nonlinear couplings,propose big challenges to the c...Waste water treatment process(WWTP)control has been attracting more and more attention.However,various undesired factors,such as disturbance,uncertainties,and strong nonlinear couplings,propose big challenges to the control of a WWTP.In order to improve the control performance of the closed-loop system and guarantee the discharge requirements of the effluent quality,rather than take the model dependent control approaches,an active disturbance rejection control(ADRC)is utilized.Based on the control signal and system output,a phase optimized ADRC(POADRC)is designed to control the dissolved oxygen and nitrate concentration in a WWTP.The phase advantage of the phase optimized extended state observer(POESO),convergence of the POESO,and stability of the closed-loop system are analyzed from the theoretical point of view.Finally,a commonly accepted benchmark simulation model no.1.(BSM1)is utilized to test the POESO and POADRC.Linear active disturbance rejection control(LADRC)and the suggested proportion-integration(PI)control are taken to make a comparative research.Both system responses and performance index values confirm the advantage of the POADRC over the LADRC and the suggested PI control.Numerical results show that,as a result of the leading phase of the total disturbance estimation,the POESO based POADRC is an effective and promising way to control the dissolved oxygen and nitrate concentration so as to ensure the effluent quality of a WWTP.展开更多
Red,blue and green visible lasers are more attractive with the development of the science and technology.Self frequency doubling is an important approach to realize visible lasers.For self frequency doubling,the basic...Red,blue and green visible lasers are more attractive with the development of the science and technology.Self frequency doubling is an important approach to realize visible lasers.For self frequency doubling,the basic requests are high figure of merit(FOM),high damage threshold,good chemical stability and mechanical properties.Perfection and growth characters are also important for a practical SFD crystal. In recent years,the discovery of rare earth calcium oxyborates has resulted in the renewal in the field of SFD crystal.ReCaO(BO 3) 3(ReCOB)is a new type of novel nonlinear optical crystals which is nearly congruently melt and can be grown with Czochralski method.ReCOB crystals possess high nonlinear coefficients and damage thresholds.They are non hydroscopic and easy cutting and polishing.They belong to monoclinic with point group m and space group cm.The strong anisotropy originated from the low symmetry makes the measurement and application of the crystal more complicated.More than half of naturally existed crystals belongs to low symmetry,consequently,the research on the nonlinear and anisotropic laser optical properties are not only important for ReCOB crystal,but also useful for the applications of other low symmetry crystals.展开更多
Simulation of phased array beams in dovetail and austenitic welds is conducted to optimize the setup of phased array ultrasonic testing（PAUT）.To simulate the beam in such material with complex geometry or with chara...Simulation of phased array beams in dovetail and austenitic welds is conducted to optimize the setup of phased array ultrasonic testing（PAUT）.To simulate the beam in such material with complex geometry or with characteristic of anisotropy and inhomogeneity, firstly,linear phased multi-Gaussian beam（LPMGB） models are introduced and discussed. Then,in the case of dovetail,wedge is designed to maximize the stable amplitude of the beam along the steering path;in the case of austenitic weld,modified focal law are developed to solve the problem of beam screwing and defocusing due to the material properties.To verify the effectiveness of the modified focal law,beam fields are calculated using LPMGB model in austenitic welds.展开更多
Motivated by the application of （Ti, Al）N alloy compound in the coating layer, the ternary phase diagram of Ti-Al-N was analyzed by the calculation of the phase diagram （CALPHAD） technique. The isothermal sections...Motivated by the application of （Ti, Al）N alloy compound in the coating layer, the ternary phase diagram of Ti-Al-N was analyzed by the calculation of the phase diagram （CALPHAD） technique. The isothermal sections of the Ti-Al-N ternary system were constructed and compared with the literature experimental results. The thermodynamic parameters of the Ti-Al-N ternary system and the related Ti-N and Al-N binary systems were adopted from literatures, whereas, those of the Ti-Al binary from the literatures were adjusted according to both the ternary and the binary phase equilibria. The consistency between the calculated results and the experimental data shows that considering the ternary thermodynamic relationship, the adjustments to the thermodynamic parameters of the related binaries are necessary.展开更多
A computer-assisted method is presented for optimization of mobile phase compositions and development distance in gradient two-step development HPTLC. The method is based on a system which can predict the final R(f) v...A computer-assisted method is presented for optimization of mobile phase compositions and development distance in gradient two-step development HPTLC. The method is based on a system which can predict the final R(f) values for gradient two-step development from values measured using five preliminary runs. The statistical scanning method is then used for optimization, using R(f) difference as the selection criterion. The method was evaluated using a mixture of eight components. Excellent agreement was obtained between predicted and experimental results.展开更多
A computer-assisted method is presented for optimization for the selection of mobile phase composition in semi-preparative HPLC.The optimization for the expected separation is based on a polynomial estimation from fiv...A computer-assisted method is presented for optimization for the selection of mobile phase composition in semi-preparative HPLC.The optimization for the expected separation is based on a polynomial estimation from five preliminary runs.Statistical scanning technique was used for optimization.Double criteria simulation system (DCSS) is established for chromatographic perfor- mance measurement in this method.The validity of the optimization strategy is confirmed by applying it to a technical Cypermethrin separation.Excellent agreement is obtained between the predicted and experimental results.展开更多
The basic principle of optimal method called “moving overlapping resolution mapping Method” to select the optimal binary mobile phase composition of multi-step linear gradient liquid chromatography is discussed with...The basic principle of optimal method called “moving overlapping resolution mapping Method” to select the optimal binary mobile phase composition of multi-step linear gradient liquid chromatography is discussed with simultaneously considering effects of position of solute inside the column and mobile phase composition on peak resolution and retention value, then a BASIC program based on this principle is developed in IBM-PC computer. The validities of both principle of optimization and BASIC program are confirmed by separation of samples Containing bile acids and PAHs in RP-HPLC.展开更多
A linear accelerator as a new injector for the SSC （Separated Sector Cyclotron） of the HIRFL （Heavy Ion Research Facility Lanzhou） is being designed. The DTL （Drift-Tube-Linac） has been designed to accelerate ^2...A linear accelerator as a new injector for the SSC （Separated Sector Cyclotron） of the HIRFL （Heavy Ion Research Facility Lanzhou） is being designed. The DTL （Drift-Tube-Linac） has been designed to accelerate ^238U^34＋ from 0.140 MeV/u to 0.97 MeV/u. To the first accelerating tank which accelerates ^238U^34＋ to 0.54 MeV/u, the approach of Alternating-Phase-Focusing （APF） is applied. The phase array is obtained by coupling optimization software Dakota and beam optics code LINREV. With the hybrid of Multi- objective Genetic Algorithm （MOGA） and a pattern search method, an optimum array of asynchronous phases is determined. The final growth, both transversely and longitudinally, can meet the design requirements. In this paper, the deign optimization of the APF DTL is presented.展开更多
The active multi-beam antenna can be widely used in the 6G integrated satellite network project,the national satellite Internet project,and other major satellite projects.It determines the key performance indicators o...The active multi-beam antenna can be widely used in the 6G integrated satellite network project,the national satellite Internet project,and other major satellite projects.It determines the key performance indicators of the satellite such as the service coverage area and the communication capacity of all the beams in the forward link and the return link.The active multi-beam antenna is the core technology of satellite payload and has been developed rapidly in recent years.Based on the antenna performance requirements such as the number of giant-scale beams,super-large coverage area,high gain,and high carrier-to-interference ratio(C/I),this paper proposes a new active multi-beam antenna design method,which integrates the multi-objective coordination and multi-feed amplitude and phase weighted optimization algorithms.A balanced optimal solution that meets the performance requirements can be obtained by constraining each other with different objective functions.In the optimization process,the surrogate model of convolutional autoencoder based on artificial intelligence technology is proposed for multi-objective optimization solution,which efficiently completes the search of optimal beam excitation coefficients.This paper takes the demand for very-high-throughput communication satellites serving the Asia-Pacific region as an example and applies the design method to the multi-beam antenna design of the satellite.The simulation verification of the antenna is completed,achieving good performance of 976 beams.All results meet the performance requirements,supporting the implementation of 1 Tbps communication capacity for the entire satellite,and verifying the correctness of the design method.展开更多
文摘Efficiency and emissions of spark-ignited engines are significantly affected by combustion phase which can usually be indicated by crank angle of 50% mass burnt （CA50）. Managing combustion phase at the optimal value at which the maximal efficiency can be achieved is a challenging issue due to the cyclic variations of combustion process. This paper addresses this issue in two loops： CA50 set-point optimization （outer loop） and set-point tracking （inner loop） by controlling spark advance （SA）. Extremum seeking approach maximizing thermal efficiency is employed in the CA50 set-point optimization. A proportional- integral （PI） controller is adopted to make the moving average value of CA50 tracking the optimal CA50 set-point determined in the outer loop. Moreover, in order to obtain fast responses at steady and transient operations, feed-forward maps are designed for extremum seeking controller and PI controller, respectively. Finally, experimental validations are conducted on a six-cylinder gasoline at steady and transient operations to show the effectiveness of proposed control scheme.
基金supported by the National Natural Science Foundation of China(6167309361370152)the Science and Technology Project of Shenyang(F16-205-1-01)
文摘In this paper, a new partial transmit sequence（PTS）scheme with low computational complexity is proposed for the problems of high computational complexity in the conventional PTS method. By analyzing the relationship of candidate sequences in the PTS method under the interleaved partition method, it has been discovered that some candidate sequences generated by phase factor sequences have the same peak average power ratio（PAPR）. Hence, phase factor sequences can be optimized to reduce their searching times. Then, the computational process of generating candidate sequences can be simplified by improving the utilization of data and minimizing the calculations of complex multiplication. The performance analysis shows that, compared with the conventional PTS scheme, the proposed approach significantly decreases the computational complexity and has no loss of PAPR performance.
文摘Revised phase diagram of the CeO2-ZrO2 system is optimized and the lattice stability parameters of CeO2 of various phases as well as solution parameters of phases (liquid, cubic, tetragonal and monoclinic) are simultaneously obtained by using the Kaufman and Nesor's model for describing the ceramic solutions and the Lukas program
文摘In this paper a critical assessment and optimization of the phase diagrams and thermodynamic properties of the PrCl_3-MCl(M=Li,Na)and PrCl_3-MCl_2(M=Mg,Ca,Sr,Ba) binary systems have been per- formed.The assessed and optimized binary phase diagrams and thermodynamic data with self consistency are a better basis for constructing multicomponent phase diagrams.
基金National Key Research and Development Program of China(2022YFB4200400)funded by MOSTNational Natural Science Foundation of China(52172048,22205130,52402051)+10 种基金Shandong Provincial Natural Science Foundation(ZR2021ZD06,2023HWYQ-026,ZR2024JQ005)Guangdong Basic and Applied Basic Research Foundation(2023A1515012323,2023A1515010943,2022A1515110643,2024A1515010023,2025A1515010144,2025A1515010089)Shenzhen Science and Technology Program(JCYJ20240813100910014,JCYJ20240813101003005)Qingdao New Energy Shandong Laboratory open Project(QNESL OP 202309)Jiangxi Provincial Key Laboratory of Functional Crystalline Materials Chemistry(20212BCD42018)Young Talent of Lifting engineering for Science and Technology in Shandong,China(SDAST2024QTA026)Fundamental Research Funds of Shandong UniversityBasic Research Program of Jiangsu(BK20240434)Open Fund of the State Key Laboratory of Luminescent Materials and Devices(South China University of Technology,2024-skllmd-16)Open Foundation of State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures(MMCS2023OF04)Open Foundation of Key Laboratory of Mine Water Resource Utilization of Anhui Higher Education Institutes(KMWRU202405)。
文摘All-small-molecule organic solar cells(ASM OSCs)have emerged as promising photovoltaic technologies due to their excellent batch-to-batch reproducibility and potential for scalable manufacturing.However,the development of eco-friendly processing protocols using halogen-free solvents combined with sustainable solid additives remains unexplored,despite being crucial for realizing green and efficient ASM OSC production.Herein,we demonstrate the first successful integration of plant-extracted apigenin(AP)as a green solid additive with tetrahydrofuran(THF),a non-halogenated processing solvent,in ASM OSC fabrication.Systematic investigations reveal that AP establishes hydrogen-bonding interactions with the acceptor molecules,thereby promoting tighter molecular packing and enhancing crystallinity.Simultaneously,the additive modulates donor-acceptor miscibility to optimize phase-separated domain sizes.These synergistic effects generate a well-interconnected nanomorphology with balanced charge transport pathways,effectively facilitating exciton dissociation while suppressing charge recombination.The resultant devices obtain a remarkable power conversion efficiency(PCE)of 14.51%,representing one of the highest performances among halogen-free processed binary ASM OSCs reported to date.This pioneering work establishes a viable pathway toward sustainable OSC manufacturing by demonstrating that eco-friendly additives can synergistically cooperate with non-ha logenated solvents to simultaneously enhance device performance and process sustainability.
文摘Aberration-corrected focus scanning is crucial for high-precision optics,but the conventional optical systems rely on bulky and complicated dynamic correctors.Recently,Shiyi Xiao's group proposed a method using two rotating cascaded transmissive metasurfaces for adaptive aberration correction in focus scanning.The optimized phase profiles enable precise control of the focal position for scanning custom-curved surfaces.This concept was experimentally validated by two allsilicon meta-devices in the terahertz regime,paving the way for high-precision and compact optical devices in various applications.
基金National Natural Science Foundation of China(No.42374013)National Key Research and Development Program of China(Nos.2019YFC1509201,2021YFB3900604-03)。
文摘In the past two decades,extensive and in-depth research has been conducted on Time Series InSAR technology with the advancement of high-performance SAR satellites and the accumulation of big SAR data.The introduction of distributed scatterers in Distributed Scatterers InSAR(DS-InSAR)has significantly expanded the application scenarios of InSAR geodetic measurement by increasing the number of measurement points.This study traces the history of DS-InSAR,presents the definition and characteristics of distributed scatterers,and focuses on exploring the relationships and distinctions among proposed algorithms in two crucial steps:statistically homogeneous pixel selection and phase optimization.Additionally,the latest research progress in this field is tracked and the possible development direction in the future is discussed.Through simulation experiments and two real InSAR case studies,the proposed algorithms are compared and verified,and the advantages of DS-InSAR in deformation measurement practice are demonstrated.This work not only offers insights into current trends and focal points for theoretical research on DS-InSAR but also provides practical cases and guidance for applied research.
基金supported financially by the Natural Science Foundation of Shandong Province,China(grant numbers ZR2020QE067,ZR2020QB117,and ZR2022MB143)the New Colleges and Universities Twenty Foundational Projects of Jinan City,China(grant number 2021GXRC068)+2 种基金the National Natural Science Foundation of China,China(grant number 22208174)The Scientific Research Foundation in Qilu University of Technology(Shandong Academy of Sciences),China(grant numbers 2023PY002)The Talent research project of Qilu University of Technology(Shandong Academy of Sciences),China(grant numbers 2023RCKY013)。
文摘Vanadium-based electrodes are regarded as attractive cathode materials in aqueous zinc ion batteries(ZIBs)caused by their high capacity and unique layered structure.However,it is extremely challenging to acquire high electrochemical performance owing to the limited electronic conductivity,sluggish ion kinetics,and severe volume expansion during the insertion/extraction process of Zn^(2+).Herein,a series of V_(2)O_(3)nanospheres embedded N-doped carbon nanofiber structures with various V_(2)O_(3)spherical morphologies(solid,core-shell,hollow)have been designed for the first time by an electrospinning technique followed thermal treatments.The N-doped carbon nanofibers not only improve the electrical conductivity and the structural stability,but also provides encapsulating shells to prevent the vanadium dissolution and aggregation of V_(2)O_(3)particles.Furthermore,the varied morphological structures of V_(2)O_(3)with abundant oxygen vacancies can alleviate the volume change and increase the Zn^(2+)pathway.Besides,the phase transition between V_(2)O_(3)and Zn_XV_(2)O_(5-m)·n H_(2)O in the cycling was also certified.As a result,the as-obtained composite delivers excellent long-term cycle stability and enhanced rate performance for coin cells,which is also confirmed through density functional theory(DFT)calculations.Even assembled into flexible ZIBs,the sample still exhibits superior electrochemical performance,which may afford new design concept for flexible cathode materials of ZIBs.
基金supported in part by the National Key R&D Program of China under Grant 2022YFB3104503in part by the China Postdoctoral Science Foundation under Grant 2024M750199+1 种基金in part by the National Natural Science Foundation of China under Grant 62202054,Grant 62002022 and Grant 62472251in part by the Fundamental Research Funds for the Central Universities under Grant BLX202360.
文摘This paper investigates an unmanned aerial vehicle(UAV)-assisted multi-object offloading scheme for blockchain-enabled Vehicle-to-Everything(V2X)systems.Due to the presence of an eavesdropper(Eve),the system’s com-munication links may be insecure.This paper proposes deploying an intelligent reflecting surface(IRS)on the UAV to enhance the communication performance of mobile vehicles,improve system flexibility,and alleviate eavesdropping on communication links.The links for uploading task data from vehicles to a base station(BS)are protected by IRS-assisted physical layer security(PLS).Upon receiving task data,the computing resources provided by the edge computing servers(MEC)are allocated to vehicles for task execution.Existing blockchain-based computation offloading schemes typically focus on improving network performance,such as minimizing energy consumption or latency,while neglecting the Gas fees for computation offloading and the costs required for MEC computation,leading to an imbalance between service fees and resource allocation.This paper uses a utility-oriented computation offloading scheme to balance costs and resources.This paper proposes alternating phase optimization and power optimization to optimize the energy consumption,latency,and communication secrecy rate,thereby maximizing the weighted total utility of the system.Simulation results demonstrate a notable enhancement in the weighted total system utility and resource utilization,thereby corroborating the viability of our approach for practical applications.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant 62271099。
文摘The flexibility of unmanned aerial vehicles(UAVs)allows them to be quickly deployed to support ground users.Intelligent reflecting surface(IRS)can reflect the incident signal and form passive beamforming to enhance the signal in the specific direction.Motivated by the promising benefits of both technologies,we consider a new scenario in this paper where a UAV uses non-orthogonal multiple access to serve multiple users with IRS.According to their distance to the UAV,the users are divided into the close users and remote users.The UAV hovers above the close users due to their higher rate requirement,while the IRS is deployed near the remote users to enhance their received power.We aim at minimizing the transmit power of UAV by jointly optimizing the beamforming of UAV and the phase shift of IRS while ensuring the decoding requirement.However,the problem is non-convex.Therefore,we decompose it into two sub-problems,including the transmit beamforming optimization and phase shift optimization,which are transformed into second-order cone programming and semidefinite programming,respectively.We propose an iterative algorithm to solve the two sub-problems alternatively.Simulation results prove the effectiveness of the proposed scheme in minimizing the transmit power of UAV.
基金supported by the National Natural Science Foundation of China(Grant No.61971117)the Natural Science Foundation of Hebei Province(Grant No.F2020501007)the S&T Program of Hebei(No.22377717D)。
文摘This paper considers a high energy efficiency dynamic connected(HEDC)structure,which promotes the practicability and reduces the power consumption of hybrid precoding system by lowresolution phase shifters(PSs).Based on the proposed structure,a new hybrid precoding algorithm is presented to optimize the energy efficiency,namely,HP-HEDC algorithm.Firstly,via a new defined effective optimal precoding matrix,the problem of optimizing the analog switch precoding matrix is formulated as a sparse representation problem.Thus,the optimal analog switch precoding matrix can be readily obtained by the branch-and-bound method.Then,the digital precoding matrix optimization problem is modeled as a dictionary update problem and solved by the method of optimal direction(MOD).Finally,the diagonal entries of the analog PS precoding matrix are optimized by exhaustive search independently since PS and antenna is one-to-one.Simulation results show that the HEDC structure enjoys low power consumption and satisfactory spectral efficiency.The proposed algorithm presents at least 50%energy efficiency improvement compared with other algorithms when the PS resolution is set as 3-bit.
基金supported by the Key program of Beijing Municipal Education Commission(KZ201810011012)National Natural Science Foundation of China(61873005)Support Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th Fiveyear Plan(CIT&TCD201704044)。
文摘Waste water treatment process(WWTP)control has been attracting more and more attention.However,various undesired factors,such as disturbance,uncertainties,and strong nonlinear couplings,propose big challenges to the control of a WWTP.In order to improve the control performance of the closed-loop system and guarantee the discharge requirements of the effluent quality,rather than take the model dependent control approaches,an active disturbance rejection control(ADRC)is utilized.Based on the control signal and system output,a phase optimized ADRC(POADRC)is designed to control the dissolved oxygen and nitrate concentration in a WWTP.The phase advantage of the phase optimized extended state observer(POESO),convergence of the POESO,and stability of the closed-loop system are analyzed from the theoretical point of view.Finally,a commonly accepted benchmark simulation model no.1.(BSM1)is utilized to test the POESO and POADRC.Linear active disturbance rejection control(LADRC)and the suggested proportion-integration(PI)control are taken to make a comparative research.Both system responses and performance index values confirm the advantage of the POADRC over the LADRC and the suggested PI control.Numerical results show that,as a result of the leading phase of the total disturbance estimation,the POESO based POADRC is an effective and promising way to control the dissolved oxygen and nitrate concentration so as to ensure the effluent quality of a WWTP.
文摘Red,blue and green visible lasers are more attractive with the development of the science and technology.Self frequency doubling is an important approach to realize visible lasers.For self frequency doubling,the basic requests are high figure of merit(FOM),high damage threshold,good chemical stability and mechanical properties.Perfection and growth characters are also important for a practical SFD crystal. In recent years,the discovery of rare earth calcium oxyborates has resulted in the renewal in the field of SFD crystal.ReCaO(BO 3) 3(ReCOB)is a new type of novel nonlinear optical crystals which is nearly congruently melt and can be grown with Czochralski method.ReCOB crystals possess high nonlinear coefficients and damage thresholds.They are non hydroscopic and easy cutting and polishing.They belong to monoclinic with point group m and space group cm.The strong anisotropy originated from the low symmetry makes the measurement and application of the crystal more complicated.More than half of naturally existed crystals belongs to low symmetry,consequently,the research on the nonlinear and anisotropic laser optical properties are not only important for ReCOB crystal,but also useful for the applications of other low symmetry crystals.
基金supported by the Korea Science and Engineering Foundation(KOSEF) grant funded by the Korea government(MOST)(2006-01653)NSFC-NRF,and by the National Natural Science Foundation of China(NSFC)
文摘Simulation of phased array beams in dovetail and austenitic welds is conducted to optimize the setup of phased array ultrasonic testing（PAUT）.To simulate the beam in such material with complex geometry or with characteristic of anisotropy and inhomogeneity, firstly,linear phased multi-Gaussian beam（LPMGB） models are introduced and discussed. Then,in the case of dovetail,wedge is designed to maximize the stable amplitude of the beam along the steering path;in the case of austenitic weld,modified focal law are developed to solve the problem of beam screwing and defocusing due to the material properties.To verify the effectiveness of the modified focal law,beam fields are calculated using LPMGB model in austenitic welds.
基金This study was financially supported by the National Natural Science Foundation of China (No.50671009)the National Doc-torate Fund of the Education Ministry of China (No.20060008015).
文摘Motivated by the application of （Ti, Al）N alloy compound in the coating layer, the ternary phase diagram of Ti-Al-N was analyzed by the calculation of the phase diagram （CALPHAD） technique. The isothermal sections of the Ti-Al-N ternary system were constructed and compared with the literature experimental results. The thermodynamic parameters of the Ti-Al-N ternary system and the related Ti-N and Al-N binary systems were adopted from literatures, whereas, those of the Ti-Al binary from the literatures were adjusted according to both the ternary and the binary phase equilibria. The consistency between the calculated results and the experimental data shows that considering the ternary thermodynamic relationship, the adjustments to the thermodynamic parameters of the related binaries are necessary.
文摘A computer-assisted method is presented for optimization of mobile phase compositions and development distance in gradient two-step development HPTLC. The method is based on a system which can predict the final R(f) values for gradient two-step development from values measured using five preliminary runs. The statistical scanning method is then used for optimization, using R(f) difference as the selection criterion. The method was evaluated using a mixture of eight components. Excellent agreement was obtained between predicted and experimental results.
文摘A computer-assisted method is presented for optimization for the selection of mobile phase composition in semi-preparative HPLC.The optimization for the expected separation is based on a polynomial estimation from five preliminary runs.Statistical scanning technique was used for optimization.Double criteria simulation system (DCSS) is established for chromatographic perfor- mance measurement in this method.The validity of the optimization strategy is confirmed by applying it to a technical Cypermethrin separation.Excellent agreement is obtained between the predicted and experimental results.
文摘The basic principle of optimal method called “moving overlapping resolution mapping Method” to select the optimal binary mobile phase composition of multi-step linear gradient liquid chromatography is discussed with simultaneously considering effects of position of solute inside the column and mobile phase composition on peak resolution and retention value, then a BASIC program based on this principle is developed in IBM-PC computer. The validities of both principle of optimization and BASIC program are confirmed by separation of samples Containing bile acids and PAHs in RP-HPLC.
基金Supported by the National Natural Science Foundation of China (10635090)
文摘A linear accelerator as a new injector for the SSC （Separated Sector Cyclotron） of the HIRFL （Heavy Ion Research Facility Lanzhou） is being designed. The DTL （Drift-Tube-Linac） has been designed to accelerate ^238U^34＋ from 0.140 MeV/u to 0.97 MeV/u. To the first accelerating tank which accelerates ^238U^34＋ to 0.54 MeV/u, the approach of Alternating-Phase-Focusing （APF） is applied. The phase array is obtained by coupling optimization software Dakota and beam optics code LINREV. With the hybrid of Multi- objective Genetic Algorithm （MOGA） and a pattern search method, an optimum array of asynchronous phases is determined. The final growth, both transversely and longitudinally, can meet the design requirements. In this paper, the deign optimization of the APF DTL is presented.
基金supported by the Fund from the National Natural Science Foundation of China(Grant No.62271387)a pre-research project on Civil Aerospace Technologies(Grant No.D010203).
文摘The active multi-beam antenna can be widely used in the 6G integrated satellite network project,the national satellite Internet project,and other major satellite projects.It determines the key performance indicators of the satellite such as the service coverage area and the communication capacity of all the beams in the forward link and the return link.The active multi-beam antenna is the core technology of satellite payload and has been developed rapidly in recent years.Based on the antenna performance requirements such as the number of giant-scale beams,super-large coverage area,high gain,and high carrier-to-interference ratio(C/I),this paper proposes a new active multi-beam antenna design method,which integrates the multi-objective coordination and multi-feed amplitude and phase weighted optimization algorithms.A balanced optimal solution that meets the performance requirements can be obtained by constraining each other with different objective functions.In the optimization process,the surrogate model of convolutional autoencoder based on artificial intelligence technology is proposed for multi-objective optimization solution,which efficiently completes the search of optimal beam excitation coefficients.This paper takes the demand for very-high-throughput communication satellites serving the Asia-Pacific region as an example and applies the design method to the multi-beam antenna design of the satellite.The simulation verification of the antenna is completed,achieving good performance of 976 beams.All results meet the performance requirements,supporting the implementation of 1 Tbps communication capacity for the entire satellite,and verifying the correctness of the design method.
