Specially designed fibers are widely used in engineering practice because the specially-designed shape can help to improve the bonding strength of the fiber and the interface. Studied in this paper is the interfacial ...Specially designed fibers are widely used in engineering practice because the specially-designed shape can help to improve the bonding strength of the fiber and the interface. Studied in this paper is the interfacial shear stress transfer behavior on both sides of the specially designed fiber when it is being pulled out; in which automatic analysis of three-dimensional photoelasticity is employed and the finite element method is adopted. The results show that the stress transfer occurs mainly in the region near the fiber＇s embedded end where the stress reaches its critical point, leading to debonding of the interface. Before debonding, as the pullout loading increases, the peak value of shear stress transfers along the fiber from the embedded end to the interior of the matrix, and then stops at the hooked part of the fiber because of its impediment. When the interface begins to debond as the load increases, the shear stress can be transferred to the hooked part.展开更多
Basalt fibers/7075 aluminum matrix composites were studied to meet the demand of aluminum alloy drill pipes for material wear resistance.The composites with different basalt fiber additions were prepared by hot presse...Basalt fibers/7075 aluminum matrix composites were studied to meet the demand of aluminum alloy drill pipes for material wear resistance.The composites with different basalt fiber additions were prepared by hot pressed sintering and hot extrusion.The mechanical properties as well as friction and wear properties of the composites were studied by microstructure analysis,tensile experiments,friction and wear experiments.The results showed that basalt fibers were oriented and uniformly distributed and led to local grain refinement in the alloy matrix.The hardness and elongation of the composites were improved.The friction coefficient of the composites increased and then decreased,and the maximum wear depth and wear amount decreased,then increased,then decreased again with the growth of basalt fiber addition.Meanwhile,the inclusion of basalt fibers mitigated the uneven wear of the extruded 7075 aluminum alloy.The value of wear depth difference of 7075-0.2BF was the smallest,and that of 7075-2.0BF was close to it.The maximum wear depth and wear volume the 7075-0.2BF and 7075-2.0BF were also the smallest.The inhibition of uneven wear by basalt fibers enhanced of wear resistance for 7075 aluminum alloy,which has reference significance for improving the performance of aluminum alloy drill pipes.展开更多
Fiber reinforced ceramic matrix composites(FRCMCs)are the preferred materials for safety critical components in the fields of aerospace,nuclear engineering,and transportation,with broad market and application prospect...Fiber reinforced ceramic matrix composites(FRCMCs)are the preferred materials for safety critical components in the fields of aerospace,nuclear engineering,and transportation,with broad market and application prospects.However,due to the characteristics of multiphase,heterogeneity,and anisotropy,key issues such as poor adhesion,high porosity,and crack propagation urgently need to be addressed in the fabrication and machining of FRCMCs.With the increasing demand for FRCMCs parts,high-quality and reliable design and fabrication,performance evaluation,and precision manufacturing have become a series of hot issues.There is a lack of systematic review in capturing the current research status and development direction of FRCMCs fabrication and machining.This research aims to comprehensively review and critically evaluate the existing understanding of the fabrication and machining of FRCMCs.This study can provide scientists with a deeper understanding of the shape control mechanism of FRCMCs fabrication and machining,the theoretical basis of material synchronous removal,machining performance,and development direction.Firstly,the basic characteristics and application background of FRCMCs are introduced.Secondly,by comparing and analyzing the typical fabrication process of FRCMCs,the advantages,disadvantages,and performance evaluation of different processes are comprehensively evaluated.Thirdly,the material removal mechanisms and machining performance evaluation standards of traditional mechanical machining technologies(drilling,milling,grinding)and non-traditional mechanical machining technologies(ultrasonic,laser,water jet,discharge,wire saw,and multi-field hybrid machining)are discussed and analyzed.Finally,the challenges,development trends,and prospects faced by FRCMCs in the fields of fabrication,machining,and application are analyzed.This study not only elucidates the basic processes and key difficulties in the fabrication of FRCMCs,but also provides valuable insights for low-damage machining.展开更多
UHMWPE fibers exhibit impressive modulus and strength,but they have not reached their theoretical limits.Researchers focus on molecular weight,orientation,and crystallinity of UHMWPE,yet their contributions to mechani...UHMWPE fibers exhibit impressive modulus and strength,but they have not reached their theoretical limits.Researchers focus on molecular weight,orientation,and crystallinity of UHMWPE,yet their contributions to mechanical properties are unclear.Molecular dynamics simulations are valuable but often limited by computational constraints.Our aim is to simulate higher molecular weights to better represent real UHMWPE fibers.We used Packmol and Polyply methodologies to construct PE systems,with Polyply reproducing more reasonable properties of UHMWPE fibers.Additionally,tensile simulations showed that orientation and crystallinity greatly impact Young's modulus more than molecular weight.Energy decomposition indicated that higher molecular weights lead to covalent bonds that can withstand more energy during stretching,thus increasing breaking strength.Combining simulations with machine learning,we found that orientation has the most significant impact on Young's modulus,contributing 60%,and molecular weight plays the most crucial role in determining the breaking strength,accounting for 65%.This study provides a theoretical basis and guidelines for enhancing UHMWPE's modulus and strength.展开更多
The fast solution of linear equations has always been one of the hot spots in scientific computing.A kind of the diagonal matrix splitting iteration methods are provided,which is different from the classical matrix sp...The fast solution of linear equations has always been one of the hot spots in scientific computing.A kind of the diagonal matrix splitting iteration methods are provided,which is different from the classical matrix splitting methods.Taking the decomposition of the diagonal elements for coefficient matrix as the key point,some new preconditioners are constructed.Taking the tri-diagonal coefficient matrix as an example,the convergence domains and optimal relaxation factor of the new method are analyzed theoretically.The presented new iteration methods are applied to solve linear algebraic equations,even 2D and 3D diffusion problems with the fully implicit discretization.The results of numerical experiments are matched with the theoretical analysis,and show that the iteration numbers are reduced greatly.The superiorities of presented iteration methods exceed some classical iteration methods dramatically.展开更多
We designed and investigated a passive synchronized mode-locked fiber laser.The device utilizes a dual-cavity structure driven by the nonlinear polarization rotation(NPR)mechanism.Stable mode-locking is attained by sy...We designed and investigated a passive synchronized mode-locked fiber laser.The device utilizes a dual-cavity structure driven by the nonlinear polarization rotation(NPR)mechanism.Stable mode-locking is attained by synergistically controlling gain,polarization state,and optical path length in two symmetric sub-cavities.Experiments proved that repetition rate of the sub-cavities can be adjusted via the time delay line(TDL)to achieve synchronized mode-locking.The system stably generates multi-wavelength pulses at a single repetition frequency,evidenced by multiple spectral peaks and equidistant pulse sequences.These findings facilitate the development of high-performance multi-wavelength ultrashort pulse sources,crucial for optical communications,spectral analysis,and remote sensing.展开更多
We report a method for increasing the mechanical strength of carbon nanotube(CNT)fibers while enabling the uniform adhesion of cerium oxide(CeO_(2))abrasive particles to them using polyethyleneimine(PEI).Results show ...We report a method for increasing the mechanical strength of carbon nanotube(CNT)fibers while enabling the uniform adhesion of cerium oxide(CeO_(2))abrasive particles to them using polyethyleneimine(PEI).Results show that 5%of PEI increases the tensile strength of CNT fibers by approximately 175%.CeO_(2) particles were uniformly deposited on the reinforced CNT fibers by electrophoretic deposition.A flexible polishing tool was fabricated by weaving the CeO_(2)-CNT fibers into a non-woven fabric substrate.When used to polish potassium dihydrogen phosphate crystals,the tool reduced the surface roughness from 200 to 7.6 nm within 10 min.This approach has potential use for the development of new precision processing tools.展开更多
Silicon carbide fibers are considered ideal reinforcing materials for ceramic matrix composites due to their excellent mechanical properties and high-temperature performance.Different types of fibers necessitate indiv...Silicon carbide fibers are considered ideal reinforcing materials for ceramic matrix composites due to their excellent mechanical properties and high-temperature performance.Different types of fibers necessitate individual investigation due to variations in their composition and fabrication processes.This study presents a comprehensive investigation into evolution of the mechanical properties,surface microstructure,and composition of Shicolon-Ⅱ fibers subjected to argon heat treatment at temperatures ranging from 1300℃to 1700℃.The Shicolon-Ⅱ fibers are composed of small-sized β-SiC grains,SiC_(x)O_(y) amorphous phase,and a minor amount of graphite microcrystals.Following treatment in an argon atmosphere at 1300℃,the fibers maintain a monofilament tensile strength of 3.620 GPa,corresponding to a retention of 98.32%.This strength diminishes to 2.875 GPa,equating to a retention of 78.08%,after treatment at 1500℃.The reduction in mechanical properties of the fibers can be ascribed to the decomposition of the amorphous phase and the growth of β-SiC grains.Furthermore,creep resistance is an essential factor influencing the long-term performance of composite materials.After treatment at temperatures above 1400℃,the high-temperature creep resistance of the fibers is significantly enhanced due to growth of β-SiC grains.This study offers valuable theoretical insights into high-temperature applications of second-generation fibers,contributing to an enhanced understanding of their performance under extreme conditions.展开更多
An alternative elliptical and circle air-hole-assisted Al_(0.24)Ga_(0.76)As photonic crystal fiber(PCF)was proposed for generating broadband high-coherence mid-infrared supercontinuum,and the dispersion,effect-ive mod...An alternative elliptical and circle air-hole-assisted Al_(0.24)Ga_(0.76)As photonic crystal fiber(PCF)was proposed for generating broadband high-coherence mid-infrared supercontinuum,and the dispersion,effect-ive mode area and nonlinear coefficient were investigated by using finite element method(FEM),the evolu-tion of optical pulses propagating along the fiber was simulated,and the supercontinuum and the coherence were analyzed and evaluated under different pumping conditions.The results show that a supercontinuum spectrum with a spectral width of 4.852μm can be obtained in the proposed fiber with d_(1)/Λof 0.125,d_(2)/Λof 0.583 and the zero-dispersion wavelength of 3.228μm by pumping with a Gaussian pulse with a peak power of 800 W and a full width at half maximum(FWHM)of 20 fs at wavelength of 3.3μm.When the fiber is pumped by the pulse with the peak power of 2000 W,the FWHM of 80 fs at the wavelength of 4.0μm in the in the anomalous dispersion region,the modulation instability is obviously suppressed,and the high-coher-ence supercontinuum spectrum spanning from 1.1μm to 8.99μm is observed.A part of the pulse energy is transferred to the anomalous dispersion region when pumped at the wavelength of 2.8μm in the normal dis-persion region and a broadband high-coherence supercontinuum spectrum extending from 0.8μm to 9.8μm is generated in the 10 mm proposed fiber.This paper introduces elliptical air holes in the Al_(0.24)Ga_(0.76)As photonic crystal fiber,which enhances flexibility for tailoring the performance of supercontinuum,ultimately achieving the broadest supercontinuum spectrum with the shortest fiber length to date.展开更多
In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to ...In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method.展开更多
The rapid evolution of the autonomous driving industry has led to a surge in electronic units and applications,resulting in increased in-vehicle data traffic and higher demands for communication efficiency and securit...The rapid evolution of the autonomous driving industry has led to a surge in electronic units and applications,resulting in increased in-vehicle data traffic and higher demands for communication efficiency and security.Meanwhile,safe driving necessitates further development of in-vehicle thermal management systems,as traditional point-type sensors face deployment challenges due to their limited monitoring range.All-glass multimode fibers(AG-MMFs)emerge as an ideal solution for sensing and transmission.An integrated sensing and communication(ISAC)system based on AG-MMFs has been proposed and experimentally validated for stable and efficient operation across a broad temperature range from-18°C to 122°C,while maintaining strong tolerance to typical vehicle vibrations and connector misalignments.Utilizing a single commercial OM4 fiber,we achieve error-free PAM-4 transmission up to 100 Gb∕s with the aid of forward error correction and precise real-time temperature monitoring over 100 m at the same time.Furthermore,by adopting a looped link structure and a neural network-based denoising algorithm,temperature measuring maintains an average uncertainty and a spatial resolution of 0.1°C and 0.5 m,respectively,even under extreme conditions.Exhibiting such outstanding performance in both transmission and sensing,the ISAC architecture successfully addresses the growing demands for high-capacity in-vehicle networks and distributed thermal monitoring of critical components,while paving the theoretical foundation for“fiber to vehicle.”展开更多
Oil palm fiber is a natural fiber derived from agricultural biomass and has gained significant attention as an alternative reinforcement material in composite materials due to its abundance,renewability,and environmen...Oil palm fiber is a natural fiber derived from agricultural biomass and has gained significant attention as an alternative reinforcement material in composite materials due to its abundance,renewability,and environmental benefits.This review explores the various enhancement techniques applied to oil palm fiber to improve its properties for composite material development.Key areas of focus include chemical treatments,physical modifications,and hybridization with other fibers to improve fiber-matrix bonding,mechanical strength,and thermal stability.Integration of nanomaterials and bio-based resins to enhance the performance and sustainability of oil palm fiber composites is also discussed.Applications in industries such as automotive,construction,packaging,and consumer goods highlighted the potential for these composites to replace traditional,non-renewable materials.Challenges such as fiber variability,production scalability,and market adoption were examined,along with future directions in advancing oil palm fiber-based composites.展开更多
Quick and accurate determination of the optimal synchrophase angle is crucial for synchrophasing control of multi-propeller aircraft with low noise.This paper proposes a novel noise prediction and optimization strateg...Quick and accurate determination of the optimal synchrophase angle is crucial for synchrophasing control of multi-propeller aircraft with low noise.This paper proposes a novel noise prediction and optimization strategy,developing a continuous and accurate noise prediction model and obtaining its minimum by solving the Hessian matrix and Fourier-Frobenius matrix.Firstly,a novel propeller noise prediction method uses acoustic simulation pressure signals and improved propeller signatures theory to accurately estimate noise for all synchrophase angles and receiving points.Secondly,a novel optimization approach is proposed to solve the analytical solution of the minimum propeller noise:(A)A noise objective function is established,and use its first derivatives’zeros and Hessian matrix to determine the function minimum.(B)A novel Euler formula transform method is proposed to convert trigonometric polynomials into algebraic polynomials,changing the zeros of the former into those of the latter.(C)Utilize the Fourier-Frobenius matrix method to solve the zeros of algebraic polynomials.To assess the computation time and accuracy,a turboprop aircraft with two six-bladed propellers was analyzed using the computational fluid dynamics and acoustic analogy method,providing acoustic pressure signals at 20 receivers for noise prediction and optimization.The Durand-Kerner and Fourier-Frobenius matrix methods were compared.Results demonstrate that improved propeller signatures theory is more accurate,and the Hessian matrix+Fourier-Frobenius matrix method is faster and more precise than the Hessian matrix+Durand-Kerner method.展开更多
Noise interference critically impairs the stability and data accuracy of sensing systems.However,current suppression strategies fail to concurrently mitigate intrinsic system noise and extrinsic environmental noise.Th...Noise interference critically impairs the stability and data accuracy of sensing systems.However,current suppression strategies fail to concurrently mitigate intrinsic system noise and extrinsic environmental noise.This study introduces a composite denoising approach to address this challenge.This method is based on the ameliorated ellipse fitting algorithm(AEFA)and adaptive successive variational mode decomposition(ASVMD).This algorithm employs AEFA to eliminate system noise tightly coupled with direct-current and alternating-current components in the interference signal,thereby obtaining a phase signal containing only environmental noise.The ASVMD technique adaptively extracts environmental noise components predominantly present in the phase signal.To achieve optimal decomposition results automatically,the permutation entropy criterion is employed to refine decomposition parameters.The correlation coefficient is utilized to differentiate effective components from noise components in the decomposition results.Experimental results indicate that the combined AEFA and ASVMD algorithm effectively suppresses both system and environmental noises.When applied to 50 Hz vibration signal processing,the proposed approach achieves a noise reduction of 17.81 dB and a phase resolution of 35.14μrad/√Hz.Given the excellent performance of the noise suppression,the proposed approach holds great application potential in high-performance interferometric sensing systems.展开更多
Driven by advancements in mobile internet technology,images have become a crucial data medium.Ensuring the security of image information during transmission has thus emerged as an urgent challenge.This study proposes ...Driven by advancements in mobile internet technology,images have become a crucial data medium.Ensuring the security of image information during transmission has thus emerged as an urgent challenge.This study proposes a novel image encryption algorithm specifically designed for grayscale image security.This research introduces a new Cantor diagonal matrix permutation method.The proposed permutation method uses row and column index sequences to control the Cantor diagonal matrix,where the row and column index sequences are generated by a spatiotemporal chaotic system named coupled map lattice(CML).The high initial value sensitivity of the CML system makes the permutation method highly sensitive and secure.Additionally,leveraging fractal theory,this study introduces a chaotic fractal matrix and applies this matrix in the diffusion process.This chaotic fractal matrix exhibits selfsimilarity and irregularity.Using the Cantor diagonal matrix and chaotic fractal matrix,this paper introduces a fast image encryption algorithm involving two diffusion steps and one permutation step.Moreover,the algorithm achieves robust security with only a single encryption round,ensuring high operational efficiency.Experimental results show that the proposed algorithm features an expansive key space,robust security,high sensitivity,high efficiency,and superior statistical properties for the ciphered images.Thus,the proposed algorithm not only provides a practical solution for secure image transmission but also bridges fractal theory with image encryption techniques,thereby opening new research avenues in chaotic cryptography and advancing the development of information security technology.展开更多
The two distinct types of composite materials(5%to 10%)were developed using recycled polyvinyl alcohol fiber(RPA),silicon nitride fiber(SN),and reduced carbon nanoparticles(RCN).Enhanced microstructural properties and...The two distinct types of composite materials(5%to 10%)were developed using recycled polyvinyl alcohol fiber(RPA),silicon nitride fiber(SN),and reduced carbon nanoparticles(RCN).Enhanced microstructural properties and mechanical strength were attained through the application of the 3-glycidoxypropyltrimethoxysilane coupling method.The combination of the resin-like properties of RPA-SN fiber resulted in the formation of robust outer strength and a high bonding structure.RPA-RCN composite materials with a weight percentage of 10%exhibited a tensile strength of 42 MPa.In contrast,RPA-SN-RCN composite materials containing 5%to 10%demonstrated enhanced tensile,bending,and hardness properties.Pyramid structures,solid structures,and crystal phases were formed using RCN particles.The resin and silane properties on hardness were gradually 14%increasing the outside region,whereas RPA-SN-RCN(10 wt%)on average hardness were attained at 86(Shore-D).The microstructures on RPA-RCN(5%to 10%)samples were observed solid structure,twin boundary’s structure and lattice structure.The tensile strength of RPA-SN-RCN(10%)was 67.3MPa,whereas the impact strength of RPA-RCN(10 wt%)was 53 J/mm2.The scanning electron microscopies(SEM)were used to investigate the microstructure of the RPA-SN-RCN(5%)and RPA-SN-RCN(10%)composite materials,respectively.展开更多
Distributed optical fiber sensing(DOFS)technology has been widely applied in pipeline monitoring,seismic detection,and security protection due to its broad coverage,high sensitivity,and strong anti-interference capabi...Distributed optical fiber sensing(DOFS)technology has been widely applied in pipeline monitoring,seismic detection,and security protection due to its broad coverage,high sensitivity,and strong anti-interference capability.However,the acquired signals are typically noisy,exhibit complex temporal-spatial patterns,and contain high-dimensional categorical features,posing significant challenges for robust classification.To address these issues,this paper introduces an Inception-ResNet-based model for intrusion event recognition in DOFS systems.The Inception architecture extracts multi-scale features from complex vibration patterns,while the residual optimization of ResNet enables efficient deep feature propagation and stable training.Furthermore,to enhance model interpretability,a Grad-CAM-based mechanism is integrated to visualize class-discriminative regions in the vibration signals,revealing the patterns that most strongly influence the network's decisions.Extensive experiments demonstrate the effectiveness of the proposed approach,achieving an average classification accuracy of 92.6%,outperforming traditional deep learning networks even with significantly reduced training data.These results indicate that the interpretable Inception-ResNet framework not only accurately classifies complex one-dimensional sensing signals but also provides transparent and reliable support for practical DOFS applications.展开更多
As the global textile industry has accelerated its transition to a circular economy,iterative innovation in regenerated cellulose fibers has become a key industry focus.With viscose fiber having been industrialized fo...As the global textile industry has accelerated its transition to a circular economy,iterative innovation in regenerated cellulose fibers has become a key industry focus.With viscose fiber having been industrialized for over a century and lyocell fiber gaining market recognition because of its environmentally friendly process,which is the next regenerated cellulose fiber.Herein,ionic liquids with low vapor pressure,nonflammability,relatively simple recovery,and high dissolution efficiency were used to fabricate regenerated cellulose fibers.The viscose and lyocell properties of the fibers were systematically compared,including microscopic morphology,dyeing behavior,fibrillation resistance,mechanical properties,yarn-forming capacity,and fabric performance.The ionic liquid(IL)fiber exhibited a smooth surface and circular cross-section,with the highest tensile strength,moderate dyeing and fibrillation properties,and similar spinning and weaving performance.This work can provide a reference for the commercial application of regenerated cellulose fibers fabricated from ionic liquid.展开更多
Carbon dots(CDs)have been widely studied since their discovery because of simple preparation,low toxicity and excellent luminescence properties.With the deepening of research,the luminescence properties of CDs are not...Carbon dots(CDs)have been widely studied since their discovery because of simple preparation,low toxicity and excellent luminescence properties.With the deepening of research,the luminescence properties of CDs are not only limited to fluorescence,but also their afterglow properties have been widely studied.Many excellent results have been reported for afterglow CDs.Researchers have found that various organic matrixes(OMs)can fix the emission properties of CDs and provide a rigid environment,and the interaction between OMs and CDs can inhibit the non-radiative transition of triplet excitons,which can effectively activate the afterglow performance of CDs.In this review,we provide a detailed introduction to the research progress on afterglow CDs in OMs.The preparation of afterglow CDs and their related properties were analyzed and summarized based on organic polymer matrixes and organic small molecule matrixes.Organic polymer matrixes from synthetic polymers and natural polymers have been introduced.Then,the mechanism of solid and liquid afterglow of CDs by OMs is analyzed,and their applications in the fields of anti-counterfeiting,information encryption,phosphorescence detection,fingerprint recognition,lighting and so on are summarized.Finally,the challenges facing afterglow CDs in OMs are summarized,and future research is proposed.展开更多
We investigate theoretically and experimentally the chaotic dynamics of visible-wavelength all-fiber ring laser.The100-m 630 HP fibers are used to ensure high non-linearity.A 4-m Pr^(3+)/Yb^(3+)-co-doped ZBLAN fiber p...We investigate theoretically and experimentally the chaotic dynamics of visible-wavelength all-fiber ring laser.The100-m 630 HP fibers are used to ensure high non-linearity.A 4-m Pr^(3+)/Yb^(3+)-co-doped ZBLAN fiber provides the gain.The chaotic laser was pumped by the laser diodes with the maximum power of 150 mW at the wavelength of 850 nm.The peak fluorescence spectrum of Pr^(3+)/Yb^(3+)-co-doped ZBLAN fiber at the wavelength of 635 nm shows that the visiblewavelength fiber laser can be achieved by synergistic energy transfer between Pr~(3+)and Yb^(3+)ions.The chaotic fiber laser is generated by adjusting the pump power,polarization controller and the auto-correlation,permutation entropy,skewness,and kurtosis were used to analyze the characteristics of chaotic laser.The noise-like time series and delta-like auto-correlation curve indicate the chaotic output.The complexity and randomness of time series are analyzed by the permutation entropy,skewness,and kurtosis.The result shows that chaotic dynamics is stable when the pump power exceeds a certain value.The visible chaotic all-fiber laser has high stability and can be applied for real-time monitoring and sensing.We believe that this approach may also be feasible for other materials for emission in the visible range.展开更多
基金supported by the National Natural Science Foundation of China(10662005)
文摘Specially designed fibers are widely used in engineering practice because the specially-designed shape can help to improve the bonding strength of the fiber and the interface. Studied in this paper is the interfacial shear stress transfer behavior on both sides of the specially designed fiber when it is being pulled out; in which automatic analysis of three-dimensional photoelasticity is employed and the finite element method is adopted. The results show that the stress transfer occurs mainly in the region near the fiber＇s embedded end where the stress reaches its critical point, leading to debonding of the interface. Before debonding, as the pullout loading increases, the peak value of shear stress transfers along the fiber from the embedded end to the interior of the matrix, and then stops at the hooked part of the fiber because of its impediment. When the interface begins to debond as the load increases, the shear stress can be transferred to the hooked part.
基金Project(2021YFC2900200)supported by the National Key Research and Development Project of ChinaProject(20230203114SF)supported by the Key Research and Development Project of Jilin Province,China。
文摘Basalt fibers/7075 aluminum matrix composites were studied to meet the demand of aluminum alloy drill pipes for material wear resistance.The composites with different basalt fiber additions were prepared by hot pressed sintering and hot extrusion.The mechanical properties as well as friction and wear properties of the composites were studied by microstructure analysis,tensile experiments,friction and wear experiments.The results showed that basalt fibers were oriented and uniformly distributed and led to local grain refinement in the alloy matrix.The hardness and elongation of the composites were improved.The friction coefficient of the composites increased and then decreased,and the maximum wear depth and wear amount decreased,then increased,then decreased again with the growth of basalt fiber addition.Meanwhile,the inclusion of basalt fibers mitigated the uneven wear of the extruded 7075 aluminum alloy.The value of wear depth difference of 7075-0.2BF was the smallest,and that of 7075-2.0BF was close to it.The maximum wear depth and wear volume the 7075-0.2BF and 7075-2.0BF were also the smallest.The inhibition of uneven wear by basalt fibers enhanced of wear resistance for 7075 aluminum alloy,which has reference significance for improving the performance of aluminum alloy drill pipes.
基金supported by Key Laboratory of Higheffciency and Clean Mechanical Manufacture at Shandong University,Ministry of Education,the National Natural Science Foundation of China(Nos.52305484,52305475,and U23A20632)the China Postdoctoral Science Foundation(No.2024M761876)+7 种基金the Youth Innovation Team Program of Universities in Shandong Province(No.2024KJH166)the National Key Research and Development Program of China(No.2023YFC2413301)the Taishan Scholars Program(No.tsqn202408242)the Shandong Provincial Natural Science Foundation(Nos.ZR2022QE053 and ZR2022QE159)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515111124)the Major Scientific and Technological Innovation Project of Shandong Province(No.2023CXGC010207)the Major Basic Research of Shandong Provincial Natural Science Foundation(No.ZR2023ZD34)the talent research project for the pilot project of integrating science,education,and industries of Qilu University of Technology(Shandong Academy of Sciences)(No.2024RCKY009)。
文摘Fiber reinforced ceramic matrix composites(FRCMCs)are the preferred materials for safety critical components in the fields of aerospace,nuclear engineering,and transportation,with broad market and application prospects.However,due to the characteristics of multiphase,heterogeneity,and anisotropy,key issues such as poor adhesion,high porosity,and crack propagation urgently need to be addressed in the fabrication and machining of FRCMCs.With the increasing demand for FRCMCs parts,high-quality and reliable design and fabrication,performance evaluation,and precision manufacturing have become a series of hot issues.There is a lack of systematic review in capturing the current research status and development direction of FRCMCs fabrication and machining.This research aims to comprehensively review and critically evaluate the existing understanding of the fabrication and machining of FRCMCs.This study can provide scientists with a deeper understanding of the shape control mechanism of FRCMCs fabrication and machining,the theoretical basis of material synchronous removal,machining performance,and development direction.Firstly,the basic characteristics and application background of FRCMCs are introduced.Secondly,by comparing and analyzing the typical fabrication process of FRCMCs,the advantages,disadvantages,and performance evaluation of different processes are comprehensively evaluated.Thirdly,the material removal mechanisms and machining performance evaluation standards of traditional mechanical machining technologies(drilling,milling,grinding)and non-traditional mechanical machining technologies(ultrasonic,laser,water jet,discharge,wire saw,and multi-field hybrid machining)are discussed and analyzed.Finally,the challenges,development trends,and prospects faced by FRCMCs in the fields of fabrication,machining,and application are analyzed.This study not only elucidates the basic processes and key difficulties in the fabrication of FRCMCs,but also provides valuable insights for low-damage machining.
基金financially supported by the National Natural Science Foundation of China(Nos.52303298 and 52233002)。
文摘UHMWPE fibers exhibit impressive modulus and strength,but they have not reached their theoretical limits.Researchers focus on molecular weight,orientation,and crystallinity of UHMWPE,yet their contributions to mechanical properties are unclear.Molecular dynamics simulations are valuable but often limited by computational constraints.Our aim is to simulate higher molecular weights to better represent real UHMWPE fibers.We used Packmol and Polyply methodologies to construct PE systems,with Polyply reproducing more reasonable properties of UHMWPE fibers.Additionally,tensile simulations showed that orientation and crystallinity greatly impact Young's modulus more than molecular weight.Energy decomposition indicated that higher molecular weights lead to covalent bonds that can withstand more energy during stretching,thus increasing breaking strength.Combining simulations with machine learning,we found that orientation has the most significant impact on Young's modulus,contributing 60%,and molecular weight plays the most crucial role in determining the breaking strength,accounting for 65%.This study provides a theoretical basis and guidelines for enhancing UHMWPE's modulus and strength.
基金The National Natural Science Foundations of China (12202219)the Natural Science Foundations of Ningxia (2024AAC02009, 2023AAC05001)the Ningxia Youth Top Talents Training Project。
文摘The fast solution of linear equations has always been one of the hot spots in scientific computing.A kind of the diagonal matrix splitting iteration methods are provided,which is different from the classical matrix splitting methods.Taking the decomposition of the diagonal elements for coefficient matrix as the key point,some new preconditioners are constructed.Taking the tri-diagonal coefficient matrix as an example,the convergence domains and optimal relaxation factor of the new method are analyzed theoretically.The presented new iteration methods are applied to solve linear algebraic equations,even 2D and 3D diffusion problems with the fully implicit discretization.The results of numerical experiments are matched with the theoretical analysis,and show that the iteration numbers are reduced greatly.The superiorities of presented iteration methods exceed some classical iteration methods dramatically.
文摘We designed and investigated a passive synchronized mode-locked fiber laser.The device utilizes a dual-cavity structure driven by the nonlinear polarization rotation(NPR)mechanism.Stable mode-locking is attained by synergistically controlling gain,polarization state,and optical path length in two symmetric sub-cavities.Experiments proved that repetition rate of the sub-cavities can be adjusted via the time delay line(TDL)to achieve synchronized mode-locking.The system stably generates multi-wavelength pulses at a single repetition frequency,evidenced by multiple spectral peaks and equidistant pulse sequences.These findings facilitate the development of high-performance multi-wavelength ultrashort pulse sources,crucial for optical communications,spectral analysis,and remote sensing.
文摘We report a method for increasing the mechanical strength of carbon nanotube(CNT)fibers while enabling the uniform adhesion of cerium oxide(CeO_(2))abrasive particles to them using polyethyleneimine(PEI).Results show that 5%of PEI increases the tensile strength of CNT fibers by approximately 175%.CeO_(2) particles were uniformly deposited on the reinforced CNT fibers by electrophoretic deposition.A flexible polishing tool was fabricated by weaving the CeO_(2)-CNT fibers into a non-woven fabric substrate.When used to polish potassium dihydrogen phosphate crystals,the tool reduced the surface roughness from 200 to 7.6 nm within 10 min.This approach has potential use for the development of new precision processing tools.
基金National Natural Science Foundation of China(52172108)National Key R&D Program of China(2022YFB3707700)Strategic Priority Research Program of the Chinese Academy of Sciences(XDC0144005)。
文摘Silicon carbide fibers are considered ideal reinforcing materials for ceramic matrix composites due to their excellent mechanical properties and high-temperature performance.Different types of fibers necessitate individual investigation due to variations in their composition and fabrication processes.This study presents a comprehensive investigation into evolution of the mechanical properties,surface microstructure,and composition of Shicolon-Ⅱ fibers subjected to argon heat treatment at temperatures ranging from 1300℃to 1700℃.The Shicolon-Ⅱ fibers are composed of small-sized β-SiC grains,SiC_(x)O_(y) amorphous phase,and a minor amount of graphite microcrystals.Following treatment in an argon atmosphere at 1300℃,the fibers maintain a monofilament tensile strength of 3.620 GPa,corresponding to a retention of 98.32%.This strength diminishes to 2.875 GPa,equating to a retention of 78.08%,after treatment at 1500℃.The reduction in mechanical properties of the fibers can be ascribed to the decomposition of the amorphous phase and the growth of β-SiC grains.Furthermore,creep resistance is an essential factor influencing the long-term performance of composite materials.After treatment at temperatures above 1400℃,the high-temperature creep resistance of the fibers is significantly enhanced due to growth of β-SiC grains.This study offers valuable theoretical insights into high-temperature applications of second-generation fibers,contributing to an enhanced understanding of their performance under extreme conditions.
文摘An alternative elliptical and circle air-hole-assisted Al_(0.24)Ga_(0.76)As photonic crystal fiber(PCF)was proposed for generating broadband high-coherence mid-infrared supercontinuum,and the dispersion,effect-ive mode area and nonlinear coefficient were investigated by using finite element method(FEM),the evolu-tion of optical pulses propagating along the fiber was simulated,and the supercontinuum and the coherence were analyzed and evaluated under different pumping conditions.The results show that a supercontinuum spectrum with a spectral width of 4.852μm can be obtained in the proposed fiber with d_(1)/Λof 0.125,d_(2)/Λof 0.583 and the zero-dispersion wavelength of 3.228μm by pumping with a Gaussian pulse with a peak power of 800 W and a full width at half maximum(FWHM)of 20 fs at wavelength of 3.3μm.When the fiber is pumped by the pulse with the peak power of 2000 W,the FWHM of 80 fs at the wavelength of 4.0μm in the in the anomalous dispersion region,the modulation instability is obviously suppressed,and the high-coher-ence supercontinuum spectrum spanning from 1.1μm to 8.99μm is observed.A part of the pulse energy is transferred to the anomalous dispersion region when pumped at the wavelength of 2.8μm in the normal dis-persion region and a broadband high-coherence supercontinuum spectrum extending from 0.8μm to 9.8μm is generated in the 10 mm proposed fiber.This paper introduces elliptical air holes in the Al_(0.24)Ga_(0.76)As photonic crystal fiber,which enhances flexibility for tailoring the performance of supercontinuum,ultimately achieving the broadest supercontinuum spectrum with the shortest fiber length to date.
基金Supported in part by Natural Science Foundation of Guangxi(2023GXNSFAA026246)in part by the Central Government's Guide to Local Science and Technology Development Fund(GuikeZY23055044)in part by the National Natural Science Foundation of China(62363003)。
文摘In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method.
基金supported by the National Key R&D Program of China(Grant No.2023YFB2906303)the National Natural Science Foundation of China(Grant No.62225110)+1 种基金the JD Project of Hubei Province(Grant No.2023BAA013)the Innovation Fund of WNLO。
文摘The rapid evolution of the autonomous driving industry has led to a surge in electronic units and applications,resulting in increased in-vehicle data traffic and higher demands for communication efficiency and security.Meanwhile,safe driving necessitates further development of in-vehicle thermal management systems,as traditional point-type sensors face deployment challenges due to their limited monitoring range.All-glass multimode fibers(AG-MMFs)emerge as an ideal solution for sensing and transmission.An integrated sensing and communication(ISAC)system based on AG-MMFs has been proposed and experimentally validated for stable and efficient operation across a broad temperature range from-18°C to 122°C,while maintaining strong tolerance to typical vehicle vibrations and connector misalignments.Utilizing a single commercial OM4 fiber,we achieve error-free PAM-4 transmission up to 100 Gb∕s with the aid of forward error correction and precise real-time temperature monitoring over 100 m at the same time.Furthermore,by adopting a looped link structure and a neural network-based denoising algorithm,temperature measuring maintains an average uncertainty and a spatial resolution of 0.1°C and 0.5 m,respectively,even under extreme conditions.Exhibiting such outstanding performance in both transmission and sensing,the ISAC architecture successfully addresses the growing demands for high-capacity in-vehicle networks and distributed thermal monitoring of critical components,while paving the theoretical foundation for“fiber to vehicle.”
文摘Oil palm fiber is a natural fiber derived from agricultural biomass and has gained significant attention as an alternative reinforcement material in composite materials due to its abundance,renewability,and environmental benefits.This review explores the various enhancement techniques applied to oil palm fiber to improve its properties for composite material development.Key areas of focus include chemical treatments,physical modifications,and hybridization with other fibers to improve fiber-matrix bonding,mechanical strength,and thermal stability.Integration of nanomaterials and bio-based resins to enhance the performance and sustainability of oil palm fiber composites is also discussed.Applications in industries such as automotive,construction,packaging,and consumer goods highlighted the potential for these composites to replace traditional,non-renewable materials.Challenges such as fiber variability,production scalability,and market adoption were examined,along with future directions in advancing oil palm fiber-based composites.
基金supported by the National Natural Science Foundation of China(Nos.51576097,51976089)the Funding for Outstanding Doctoral Dissertation in Nanjing University of Aeronautics and Astronautics,China(No.BCXJ24-05)the Aeronautical Science Foundation of China(No.2023L060052001).
文摘Quick and accurate determination of the optimal synchrophase angle is crucial for synchrophasing control of multi-propeller aircraft with low noise.This paper proposes a novel noise prediction and optimization strategy,developing a continuous and accurate noise prediction model and obtaining its minimum by solving the Hessian matrix and Fourier-Frobenius matrix.Firstly,a novel propeller noise prediction method uses acoustic simulation pressure signals and improved propeller signatures theory to accurately estimate noise for all synchrophase angles and receiving points.Secondly,a novel optimization approach is proposed to solve the analytical solution of the minimum propeller noise:(A)A noise objective function is established,and use its first derivatives’zeros and Hessian matrix to determine the function minimum.(B)A novel Euler formula transform method is proposed to convert trigonometric polynomials into algebraic polynomials,changing the zeros of the former into those of the latter.(C)Utilize the Fourier-Frobenius matrix method to solve the zeros of algebraic polynomials.To assess the computation time and accuracy,a turboprop aircraft with two six-bladed propellers was analyzed using the computational fluid dynamics and acoustic analogy method,providing acoustic pressure signals at 20 receivers for noise prediction and optimization.The Durand-Kerner and Fourier-Frobenius matrix methods were compared.Results demonstrate that improved propeller signatures theory is more accurate,and the Hessian matrix+Fourier-Frobenius matrix method is faster and more precise than the Hessian matrix+Durand-Kerner method.
文摘Noise interference critically impairs the stability and data accuracy of sensing systems.However,current suppression strategies fail to concurrently mitigate intrinsic system noise and extrinsic environmental noise.This study introduces a composite denoising approach to address this challenge.This method is based on the ameliorated ellipse fitting algorithm(AEFA)and adaptive successive variational mode decomposition(ASVMD).This algorithm employs AEFA to eliminate system noise tightly coupled with direct-current and alternating-current components in the interference signal,thereby obtaining a phase signal containing only environmental noise.The ASVMD technique adaptively extracts environmental noise components predominantly present in the phase signal.To achieve optimal decomposition results automatically,the permutation entropy criterion is employed to refine decomposition parameters.The correlation coefficient is utilized to differentiate effective components from noise components in the decomposition results.Experimental results indicate that the combined AEFA and ASVMD algorithm effectively suppresses both system and environmental noises.When applied to 50 Hz vibration signal processing,the proposed approach achieves a noise reduction of 17.81 dB and a phase resolution of 35.14μrad/√Hz.Given the excellent performance of the noise suppression,the proposed approach holds great application potential in high-performance interferometric sensing systems.
基金supported by the National Natural Science Foundation of China(62376106)The Science and Technology Development Plan of Jilin Province(20250102212JC).
文摘Driven by advancements in mobile internet technology,images have become a crucial data medium.Ensuring the security of image information during transmission has thus emerged as an urgent challenge.This study proposes a novel image encryption algorithm specifically designed for grayscale image security.This research introduces a new Cantor diagonal matrix permutation method.The proposed permutation method uses row and column index sequences to control the Cantor diagonal matrix,where the row and column index sequences are generated by a spatiotemporal chaotic system named coupled map lattice(CML).The high initial value sensitivity of the CML system makes the permutation method highly sensitive and secure.Additionally,leveraging fractal theory,this study introduces a chaotic fractal matrix and applies this matrix in the diffusion process.This chaotic fractal matrix exhibits selfsimilarity and irregularity.Using the Cantor diagonal matrix and chaotic fractal matrix,this paper introduces a fast image encryption algorithm involving two diffusion steps and one permutation step.Moreover,the algorithm achieves robust security with only a single encryption round,ensuring high operational efficiency.Experimental results show that the proposed algorithm features an expansive key space,robust security,high sensitivity,high efficiency,and superior statistical properties for the ciphered images.Thus,the proposed algorithm not only provides a practical solution for secure image transmission but also bridges fractal theory with image encryption techniques,thereby opening new research avenues in chaotic cryptography and advancing the development of information security technology.
基金the support provided by the Department of Mechanical Engineering,AAA college of Engineering and Technology,Sivakasi,Tamilnadu,India for facilitating the experimental and characterization facilities required to carry out this research work.
文摘The two distinct types of composite materials(5%to 10%)were developed using recycled polyvinyl alcohol fiber(RPA),silicon nitride fiber(SN),and reduced carbon nanoparticles(RCN).Enhanced microstructural properties and mechanical strength were attained through the application of the 3-glycidoxypropyltrimethoxysilane coupling method.The combination of the resin-like properties of RPA-SN fiber resulted in the formation of robust outer strength and a high bonding structure.RPA-RCN composite materials with a weight percentage of 10%exhibited a tensile strength of 42 MPa.In contrast,RPA-SN-RCN composite materials containing 5%to 10%demonstrated enhanced tensile,bending,and hardness properties.Pyramid structures,solid structures,and crystal phases were formed using RCN particles.The resin and silane properties on hardness were gradually 14%increasing the outside region,whereas RPA-SN-RCN(10 wt%)on average hardness were attained at 86(Shore-D).The microstructures on RPA-RCN(5%to 10%)samples were observed solid structure,twin boundary’s structure and lattice structure.The tensile strength of RPA-SN-RCN(10%)was 67.3MPa,whereas the impact strength of RPA-RCN(10 wt%)was 53 J/mm2.The scanning electron microscopies(SEM)were used to investigate the microstructure of the RPA-SN-RCN(5%)and RPA-SN-RCN(10%)composite materials,respectively.
基金Supported by the the Academician Workstation Program of Yunnan Province(202405AF140013)High-Quality Development Special Project of the Ministry of Industry and Information Technology(TC240A9ED-56)Shanghai Agricultural Technology Innovation Project(2024-02-08-00-12-F00032)。
文摘Distributed optical fiber sensing(DOFS)technology has been widely applied in pipeline monitoring,seismic detection,and security protection due to its broad coverage,high sensitivity,and strong anti-interference capability.However,the acquired signals are typically noisy,exhibit complex temporal-spatial patterns,and contain high-dimensional categorical features,posing significant challenges for robust classification.To address these issues,this paper introduces an Inception-ResNet-based model for intrusion event recognition in DOFS systems.The Inception architecture extracts multi-scale features from complex vibration patterns,while the residual optimization of ResNet enables efficient deep feature propagation and stable training.Furthermore,to enhance model interpretability,a Grad-CAM-based mechanism is integrated to visualize class-discriminative regions in the vibration signals,revealing the patterns that most strongly influence the network's decisions.Extensive experiments demonstrate the effectiveness of the proposed approach,achieving an average classification accuracy of 92.6%,outperforming traditional deep learning networks even with significantly reduced training data.These results indicate that the interpretable Inception-ResNet framework not only accurately classifies complex one-dimensional sensing signals but also provides transparent and reliable support for practical DOFS applications.
基金financially supported by the National Natural Science Foundation of China(Nos.22005226 and 52203124)Center for Carbon Neutral Chemistry,Institute of Chemistry,Chinese Academy of Sciences(No.CCNC-202402)+1 种基金the Basic and Advanced Research Project from Wuhan Science and Technology Bureau(No.2022013988065201)Hubei Integrative Technology and Innovation Center for Advanced Fiberous Materials,project(No.XC2024G3013)。
文摘As the global textile industry has accelerated its transition to a circular economy,iterative innovation in regenerated cellulose fibers has become a key industry focus.With viscose fiber having been industrialized for over a century and lyocell fiber gaining market recognition because of its environmentally friendly process,which is the next regenerated cellulose fiber.Herein,ionic liquids with low vapor pressure,nonflammability,relatively simple recovery,and high dissolution efficiency were used to fabricate regenerated cellulose fibers.The viscose and lyocell properties of the fibers were systematically compared,including microscopic morphology,dyeing behavior,fibrillation resistance,mechanical properties,yarn-forming capacity,and fabric performance.The ionic liquid(IL)fiber exhibited a smooth surface and circular cross-section,with the highest tensile strength,moderate dyeing and fibrillation properties,and similar spinning and weaving performance.This work can provide a reference for the commercial application of regenerated cellulose fibers fabricated from ionic liquid.
基金the Youth Talent Program Startup Foundation of Qufu Normal University(No.602601)the Natural Science Foundation of Rizhao(No.RZ2021ZR37)the Natural Science Foundation of Shandong(No.ZR2022MB047)。
文摘Carbon dots(CDs)have been widely studied since their discovery because of simple preparation,low toxicity and excellent luminescence properties.With the deepening of research,the luminescence properties of CDs are not only limited to fluorescence,but also their afterglow properties have been widely studied.Many excellent results have been reported for afterglow CDs.Researchers have found that various organic matrixes(OMs)can fix the emission properties of CDs and provide a rigid environment,and the interaction between OMs and CDs can inhibit the non-radiative transition of triplet excitons,which can effectively activate the afterglow performance of CDs.In this review,we provide a detailed introduction to the research progress on afterglow CDs in OMs.The preparation of afterglow CDs and their related properties were analyzed and summarized based on organic polymer matrixes and organic small molecule matrixes.Organic polymer matrixes from synthetic polymers and natural polymers have been introduced.Then,the mechanism of solid and liquid afterglow of CDs by OMs is analyzed,and their applications in the fields of anti-counterfeiting,information encryption,phosphorescence detection,fingerprint recognition,lighting and so on are summarized.Finally,the challenges facing afterglow CDs in OMs are summarized,and future research is proposed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61975141,61575137,and61675144)。
文摘We investigate theoretically and experimentally the chaotic dynamics of visible-wavelength all-fiber ring laser.The100-m 630 HP fibers are used to ensure high non-linearity.A 4-m Pr^(3+)/Yb^(3+)-co-doped ZBLAN fiber provides the gain.The chaotic laser was pumped by the laser diodes with the maximum power of 150 mW at the wavelength of 850 nm.The peak fluorescence spectrum of Pr^(3+)/Yb^(3+)-co-doped ZBLAN fiber at the wavelength of 635 nm shows that the visiblewavelength fiber laser can be achieved by synergistic energy transfer between Pr~(3+)and Yb^(3+)ions.The chaotic fiber laser is generated by adjusting the pump power,polarization controller and the auto-correlation,permutation entropy,skewness,and kurtosis were used to analyze the characteristics of chaotic laser.The noise-like time series and delta-like auto-correlation curve indicate the chaotic output.The complexity and randomness of time series are analyzed by the permutation entropy,skewness,and kurtosis.The result shows that chaotic dynamics is stable when the pump power exceeds a certain value.The visible chaotic all-fiber laser has high stability and can be applied for real-time monitoring and sensing.We believe that this approach may also be feasible for other materials for emission in the visible range.
