Theoretical consideration was conducted on a relation between pore diameter and interfacialarea between pores and fibers when pores uniforinly distribute in C/C composites. It was shownthat bonding at the fiber/matrix...Theoretical consideration was conducted on a relation between pore diameter and interfacialarea between pores and fibers when pores uniforinly distribute in C/C composites. It was shownthat bonding at the fiber/matrix interface apparently decreased with decreasing a pore diameter,and consequently a new idea of microspace modification concept was proposed for controllingfracture behavior of C/C composites. Four types of C/C composites with various pore structureswere fabricated by hot-pressing, and their fracture behavior was investigated by three pointbending tests. The fracture behavior of the C/C composites was changed from brittle one topseudo ductile one with decreasing the pore diameter. This result supported the validity of themicrospace modification concept proposed in this paper.展开更多
A petroleum pitch was heated at 420℃for 7 h in nitrogen to prepare a carbon fiber precursor with a softening point of 295℃.The precursor was successfully melt-spun into fibers through a circular nozzle of a monofila...A petroleum pitch was heated at 420℃for 7 h in nitrogen to prepare a carbon fiber precursor with a softening point of 295℃.The precursor was successfully melt-spun into fibers through a circular nozzle of a monofilament spinning apparatus,and these were then stabilized at 320℃in air and finally carbonized at 1000℃in nitrogen to produce carbon fibers.SEM,TGA,FT-IR,and XRD were performed to characterize the petroleum pitch,the precursor,the asspun fibers,the stabilized fibers,and the carbon fibers.It is found that the precursor contains 70.5%mass fraction of mesophase that is aligned upon spinning,and aliphatic side chains that are beneficial to spinning.The carbon fibers have a radial core structure with a linear and bent type anisotropic texture.The maximum tensile strength of the carbon fiber is 650 MPa.展开更多
The oxidation resistance of isotropic pitch-based carbon fibers are sudied by thermogravimetric analysis,scanning electron microscope and mechanical propefties measure. The change of weight loss,microtextule and mecha...The oxidation resistance of isotropic pitch-based carbon fibers are sudied by thermogravimetric analysis,scanning electron microscope and mechanical propefties measure. The change of weight loss,microtextule and mechanical properties on condition of thermostatical oxidation and nonisothermal oxidation are separately mainly discussed.The results during isothermic oxidation at 316℃ showed that the weight loss of isotropic pitch-based carbon fiber increased and the strength, module rapidly decreased with prolongation of time, but the surface of carbon fiber is smoother and has not surface such as etching pits etc. The weight of isotropic pitch-based carbon fiber decreased more rapidly during the experiment of thermo-variable weight loss after 500℃ than before 500℃.展开更多
To meet the requirements of spacecraft for the thermal conductivity of resins and solve the problem of low thermal conduction efficiency when 3D printing complex parts,we propose a new type of continuous mesophase-pit...To meet the requirements of spacecraft for the thermal conductivity of resins and solve the problem of low thermal conduction efficiency when 3D printing complex parts,we propose a new type of continuous mesophase-pitch-based carbon fiber/thermoplastic polyurethane/epoxy(CMPCF/TPU/epoxy)composite filament and its preparation process in this study.The composite filament is based on the high thermal conductivity of CMPCF,the high elasticity of TPU,and the high-temperature resistance of epoxy.The tensile strength and thermal conductivity of the CMPCF/TPU/epoxy composite filament were tested.The CMPCF/TPU/epoxy composites are formed by 3D printing technology,and the composite filament is laid according to the direction of heat conduction so that the printed part can meet the needs of directional heat conduction.The experimental results show that the thermal conductivity of the printed sample is 40.549 W/(m·K),which is 160 times that of pure epoxy resin(0.254 W/(m·K)).It is also approximately 13 times better than that of polyacrylonitrile carbon fiber/epoxy(PAN-CF/epoxy)composites.This study breaks through the technical bottleneck of poor printability of CMPCF.It provides a new method for achieving directional thermal conductivity printing,which is important for the development of complex high-performance thermal conductivity products.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
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
Fiber photodetectors(FPDs)with high deformability,flexible designability,and seamless integrability with everyday textiles hold tremendous potential for the nextgeneration wearable optoelectronics.Inorganic semiconduc...Fiber photodetectors(FPDs)with high deformability,flexible designability,and seamless integrability with everyday textiles hold tremendous potential for the nextgeneration wearable optoelectronics.Inorganic semiconductors(ISCs)are considered the ideal building block to design and govern the functions of FPDs owing to their superior electrical and optical properties.Recent developments in wearable technology of ISCs,especially in fiber form factor,have driven the creation of various FPDs with smart capabilities,from light sensing,information interfacing,to sophisticated logic operating,revolutionizing human-machine interaction paradigms in many emerging fields.Herein,we present a comprehensive review of the recent progress of ISCbased FPDs.Firstly,key design principles for ISC-based FPDs are explored,encompassing material selection,fabrication technologies,device architectures,and textile integration strategies.Then,how defect engineering,alignment engineering,and heterojunction engineering of ISCs can control the optoelectronic performance of FPDs is examined.Following this,potential wearable applications of ISC-based FPDs in optical communication,image sensing,and health monitoring are analyzed.Finally,the challenges and perspectives for the design of high-performance ISC-based FPDs are outlined.展开更多
The remodeling of axonal connections following injury is an important feature driving functional recovery.The reticulospinal tract is an interesting descending motor tract that contains both excitatory and inhibitory ...The remodeling of axonal connections following injury is an important feature driving functional recovery.The reticulospinal tract is an interesting descending motor tract that contains both excitatory and inhibitory fibers.While the reticulospinal tract has been shown to be particularly prone to axonal growth and plasticity following injuries of the spinal cord,the differential capacities of excitatory and inhibitory fibers for plasticity remain unclear.As adaptive axonal plasticity involves a sophisticated interplay between excitatory and inhibitory input,we investigated in this study the plastic potential of glutamatergic(vGlut2)and GABAergic(vGat)fibers originating from the gigantocellular nucleus and the lateral paragigantocellular nucleus,two nuclei important for locomotor function.Using a combination of viral tracing,chemogenetic silencing,and AI-based kinematic analysis,we investigated plasticity and its impact on functional recovery within the first 3 weeks following injury,a period prone to neuronal remodeling.We demonstrate that,in this time frame,while vGlut2-positive fibers within the gigantocellular and lateral paragigantocellular nuclei rewire significantly following cervical spinal cord injury,vGat-positive fibers are rather unresponsive to injury.We also show that the acute silencing of excitatory axonal fibers which rewire in response to lesions of the spinal cord triggers a worsening of the functional recovery.Using kinematic analysis,we also pinpoint the locomotion features associated with the gigantocellular nucleus or lateral paragigantocellular nucleus during functional recovery.Overall,our study increases the understanding of the role of the gigantocellular and lateral paragigantocellular nuclei during functional recovery following spinal cord injury.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
Natural colored cotton(NCC)offers a sustainable,dye-free,and eco-friendly alternative for producing colored textiles.Carotenoids,a group of important natural liposoluble pigments,are known for their diverse color spec...Natural colored cotton(NCC)offers a sustainable,dye-free,and eco-friendly alternative for producing colored textiles.Carotenoids,a group of important natural liposoluble pigments,are known for their diverse color spectrum.In this study,we successfully engineered the carotenoid biosynthesis pathway specifically in cotton fibers by utilizing a fiber-specific GbEXPA2 promoter and a CaMV 35S promoter to drive the expression of two key carotenoid biosynthesis genes,CrtB and CrtI,respectively.This approach resulted in the development of a golden fiber cotton germplasm enriched withβ-carotene.Notably,the pigmentation was predominantly observed during the early developmental stages of the fiber(5–20 d post-anthesis).While the presence of carotenoids had no significant effect on plant architecture and growth,it positively influenced the fiber elongation rate,albeit with a slight reduction in fiber length and strength.This study represents a pioneering strategy for the future development of NCCs through carotenoid biofortification.展开更多
To develop a suitable production process for fiber reinforced investment casting shell mold,three methods were studied:the traditional method(M_(1)),the method of adding fiber into silica sol with mechanical stirring ...To develop a suitable production process for fiber reinforced investment casting shell mold,three methods were studied:the traditional method(M_(1)),the method of adding fiber into silica sol with mechanical stirring and ultrasonic agitation(M_(2)),and the method of adding fiber into slurry with mechanical stirring and ultrasonic agitation for durations of 3,15,30,and 45 min(M_(3)).The bending strength,high-temperature self-load deformation,and thermal conductivity of the shell molds were investigated.The results reveal that the enhancement of fiber dispersion through ultrasonic agitation improves the comprehensive performance of the shell molds.The maximum green bending strength of the shell mold by M_(2) reaches 3.29 MPa,which is 29% higher than that of the shell mold prepared by M_(1).Moreover,the high-temperature self-load deformation of the shell mold is reduced from 0.62% to 0.44%.In addition,simultaneous ultrasonic agitation and mechanical stirring effectively shorten the slurry preparation time while maintaining comparable levels of fiber dispersion.With the process M_(3)-45 min,the fillers are uniformly dispersed in the slurry,and the fired bending strength and the high-temperature self-load deformation reach 6.25 MPa and 0.41%,respectively.Therefore,the proposed ultrasonic agitation route is promising for the fabrication of fiber-reinforced shell molds with excellent fibers dispersion.展开更多
The development of high-performance bifunctional electrocatalysts is crucial for advancing zinc-air batteries.However,the fundamentally distinct mechanisms of the oxygen reduction and evolution reactions(ORR/OER)hinde...The development of high-performance bifunctional electrocatalysts is crucial for advancing zinc-air batteries.However,the fundamentally distinct mechanisms of the oxygen reduction and evolution reactions(ORR/OER)hinder the simultaneous realization of high activity within a single catalyst.Herein,we propose a spatial decoupling strategy to overcome this limitation by engineering isolated Fe singleatoms and Fe-Ir dual-atom pairs on a nitrogen-doped carbon matrix(Fe/FeIr-NC).In this architecture,Fe single atoms serve as ORR centers,while Fe-Ir pairs with tunable spacing are tailored for OER,enabling complete functional separation and independent optimization of the reactions.As a result,the catalyst delivers an ORR half-wave potential of 0.91 V and an OER overpotential of 250 mV at 10 mA cm^(-2),yielding a record-low bifunctional gap(ΔE=0.57 V)that outperforms all reported single-and dual-atom catalysts.A flexible fiber zincair battery was developed based on this catalyst,delivering a peak power density of 3920 W kg^(-1),along with a 1.4-fold increase in energy efficiency and a 2.6-fold extension in cycle life compared to the commercial Pt/C+IrO_(2)benchmark.This work not only breaks the traditional activity trade-off in bifunctional catalysis but also offers a promising route toward high-performance power sources for wearable electronics.展开更多
Materials exhibiting broadband nonlinear optical responses are critically important for ultrafast photonics applications,particularly as saturable absorbers(SAs)that facilitate broadband optical pulse generation.In th...Materials exhibiting broadband nonlinear optical responses are critically important for ultrafast photonics applications,particularly as saturable absorbers(SAs)that facilitate broadband optical pulse generation.In this study,tea polyphenolpolyvinyl alcohol(TP-PVA)composite films are synthesized via a polymer embedding method and employed as SAs to initiate ultrafast pulse operation in fiber lasers.The TP-PVA SA film exhibits excellent broadband saturable absorption performance at wavelengths of 1.0μm,1.5μm,and 2.0μm,with modulation depths of 54.21%,41.41%,and 51.16%,respectively.Stable passively mode-locked pulses with pulse widths of 588 fs,419 fs,and 743 fs are generated in Yb-,Er-,and Tm-doped fiber lasers,respectively.This work confirms the effective performance of TP-PVA as a broadband SA,and establishes a foundation for the integration of novel and sustainable materials within ultrafast photonic systems.The approach paves the way for developing compact broadband ultrafast laser systems operating in the near-infrared spectral region.展开更多
A multi-stage stress relaxation test was performed on a granodiorite sample to understand the deformation process prior to the macroscopic failure of brittle rocks,as well as the transient response during stress relax...A multi-stage stress relaxation test was performed on a granodiorite sample to understand the deformation process prior to the macroscopic failure of brittle rocks,as well as the transient response during stress relaxation.Distributed optical fiber sensing was used to measure strains across the sample surface by helically wrapping the single-mode fiber around the cylindrical sample.Close agreement was observed between the circumferential strains obtained from the optical fibers and the extensometer.The reconstructed full-field strain contours show strain heterogeneity from the crack closure phase,and the strains in the later deformation phase are dominantly localized within the former high-strain zone.The Gini coefficient was used to quantify the degree of strain localization and shows an initial increase during the crack closure phase,a decrease during the linear elastic phase,and a subsequent increase during the post-yielding phase.This behavior corresponds to a process of initial localization from an imperfect boundary condition,homogenization,and eventual relocalization prior to the macroscopic failure of the sample.The transient strain rate decay during the stress relaxation phase was quantified using the p-value in the“Omori-like"power law function.A higher initial stress at the onset of relaxation results in a lower p-value,indicating a slower strain rate decay.As the sample approaches macroscopic failure,the lowest p-value shifts from the most damaged zone to adjacent areas,suggesting stress redistribution or crack propagation in deformed crystalline rocks under stress relaxation conditions.展开更多
Okara is produced in large quantities annually in China,but much of it is discarded due to its high content of indigestible dietary fiber(DF),contributing to significant environmental challenges.Recognizing the undere...Okara is produced in large quantities annually in China,but much of it is discarded due to its high content of indigestible dietary fiber(DF),contributing to significant environmental challenges.Recognizing the underexplored medicinal potential of DF,we developed an efficient fermentation method to enhance the bioavailability of okara fiber.In this study,Pediococcus acidilactici IFJ-1,which has strong enzymatic production capabilities and beneficial effects on gastrointestinal flora modulation,was selected to ferment okara.Results showed decreases in viscosity and particle size,optimized surface structure,improved thermal stability and hydration properties,and a significant increase in soluble DF content from 1.85%to 3.91%.To evaluate the physiological effects,hyperlipidemic mouse models were established and subjected to dietary interventions utilizing okara and fermented okara to measure changes in physicochemical parameters,gut microbiota composition,and lipid metabolism.The dietary intervention was effective,particularly in the fermented okara group,showing a 7.3%weight loss,improved blood lipids(triglycerides:‒39.8%,total cholesterol:‒12.8%,low-density lipoprotein cholesterol:‒34.2%,high-density lipoprotein cholesterol:+26.2%),and a 22.2%lower liver index.Gut microbiota analysis revealed that fermented okara positively modulated the microbial community by increasing the abundance of beneficial bacteria(e.g.,Bacteroidota)and reducing the abundance of obesity-associated bacteria(e.g.,Bacillota).Lipid metabolism profiling further demonstrated that fermented okara downregulated harmful lipids(e.g.,(O-acyl)-ω-hydroxy fatty acids,ceramides,and diacylglycerols)while upregulating beneficial phospholipids(e.g.,phosphatidylinositol,phosphatidylserine,phosphatidylethanolamine,lysophosphatidylinositol and lysophosphatidic acid).This study highlights a novel approach for enhancing DF utilization through fermentation,providing valuable insights into strategies for preventing obesity and metabolic diseases.展开更多
High-performance fiber fabrics and composites experienced transverse compression deformation at ultrahigh strain rates near the impact point when subjected to high-velocity impacts,which significantly affected their b...High-performance fiber fabrics and composites experienced transverse compression deformation at ultrahigh strain rates near the impact point when subjected to high-velocity impacts,which significantly affected their ballistic limits.In this paper,a fiber-scale experimental method for characterizing ultrahigh strain-rate transverse compression behavior was proposed.To begin with,in order to measure the extremely low stress and strain in small specimens,the conventional Hopkinson bar was reduced to the hundred-micron scale,thereby achieving wave impedance matching with single fibers.In addition,tangential and normal laser Doppler velocimetry(LDV)methods were employed to realize non-contact,high-precision,and high-speed axial velocity measurements of micron-scale incident and transmission bars,respectively.Meanwhile,a microscopic observation system was used to facilitate the installation of miniature fiber samples.The experimental setup and procedures were introduced,and the system accuracy was verified through sample-free loading tests based on one-dimensional stress wave propagation theory.Dynamic compression experiments on Graphene-UHMWPE fibers were carried out,followed by post-compression microstructural characterization via scanning electron microscopy(SEM).Results demonstrated that successful mechanical characterization was achieved at strain rates exceeding 105,an order of magnitude higher than the previously reported maximum rates.Furthermore,during the loading process,the fibers underwent uniform compression deformation while exhibiting pronounced strain-rate effects.This method offers a novel approach for dynamic mechanical characterization of microscale single fibers,enabling the development of comprehensive strain-ratedependent material models to guide the design of advanced composites and high-performance fibers.展开更多
Flexible fiber sensors,However,traditional methods face challenges in fabricating low-cost,large-scale fiber sensors.In recent years,the thermal drawing process has rapidly advanced,offering a novel approach to flexib...Flexible fiber sensors,However,traditional methods face challenges in fabricating low-cost,large-scale fiber sensors.In recent years,the thermal drawing process has rapidly advanced,offering a novel approach to flexible fiber sensors.Through the preform-tofiber manufacturing technique,a variety of fiber sensors with complex functionalities spanning from the nanoscale to kilometer scale can be automated in a short time.Examples include temperature,acoustic,mechanical,chemical,biological,optoelectronic,and multifunctional sensors,which operate on diverse sensing principles such as resistance,capacitance,piezoelectricity,triboelectricity,photoelectricity,and thermoelectricity.This review outlines the principles of the thermal drawing process and provides a detailed overview of the latest advancements in various thermally drawn fiber sensors.Finally,the future developments of thermally drawn fiber sensors are discussed.展开更多
We develop an ultrafast Yb-fiber laser system based on eight-channel coherent beam combining utilizing commercially available rod-type Yb-fibers.To ensure good combining efficiency and long-term operation of the syste...We develop an ultrafast Yb-fiber laser system based on eight-channel coherent beam combining utilizing commercially available rod-type Yb-fibers.To ensure good combining efficiency and long-term operation of the system at the attosecond laser facility under construction,we fully stabilize the phase,group-delay,and beam-pointing of the eight fiber channels.Especially,we propose a novel multi-step hill climbing method to control both group-delay and beam-pointing.At a repetition rate of 1 MHz,this laser system delivers 270-fs pulses with 1.18-k W average power(1.18-m J pulse energy).The average-power instability of the laser system running for 12 hours is 0.32%.展开更多
文摘Theoretical consideration was conducted on a relation between pore diameter and interfacialarea between pores and fibers when pores uniforinly distribute in C/C composites. It was shownthat bonding at the fiber/matrix interface apparently decreased with decreasing a pore diameter,and consequently a new idea of microspace modification concept was proposed for controllingfracture behavior of C/C composites. Four types of C/C composites with various pore structureswere fabricated by hot-pressing, and their fracture behavior was investigated by three pointbending tests. The fracture behavior of the C/C composites was changed from brittle one topseudo ductile one with decreasing the pore diameter. This result supported the validity of themicrospace modification concept proposed in this paper.
文摘A petroleum pitch was heated at 420℃for 7 h in nitrogen to prepare a carbon fiber precursor with a softening point of 295℃.The precursor was successfully melt-spun into fibers through a circular nozzle of a monofilament spinning apparatus,and these were then stabilized at 320℃in air and finally carbonized at 1000℃in nitrogen to produce carbon fibers.SEM,TGA,FT-IR,and XRD were performed to characterize the petroleum pitch,the precursor,the asspun fibers,the stabilized fibers,and the carbon fibers.It is found that the precursor contains 70.5%mass fraction of mesophase that is aligned upon spinning,and aliphatic side chains that are beneficial to spinning.The carbon fibers have a radial core structure with a linear and bent type anisotropic texture.The maximum tensile strength of the carbon fiber is 650 MPa.
文摘The oxidation resistance of isotropic pitch-based carbon fibers are sudied by thermogravimetric analysis,scanning electron microscope and mechanical propefties measure. The change of weight loss,microtextule and mechanical properties on condition of thermostatical oxidation and nonisothermal oxidation are separately mainly discussed.The results during isothermic oxidation at 316℃ showed that the weight loss of isotropic pitch-based carbon fiber increased and the strength, module rapidly decreased with prolongation of time, but the surface of carbon fiber is smoother and has not surface such as etching pits etc. The weight of isotropic pitch-based carbon fiber decreased more rapidly during the experiment of thermo-variable weight loss after 500℃ than before 500℃.
基金supported by the National Natural Science Foundation of China(Nos.52175474 and 52275498)。
文摘To meet the requirements of spacecraft for the thermal conductivity of resins and solve the problem of low thermal conduction efficiency when 3D printing complex parts,we propose a new type of continuous mesophase-pitch-based carbon fiber/thermoplastic polyurethane/epoxy(CMPCF/TPU/epoxy)composite filament and its preparation process in this study.The composite filament is based on the high thermal conductivity of CMPCF,the high elasticity of TPU,and the high-temperature resistance of epoxy.The tensile strength and thermal conductivity of the CMPCF/TPU/epoxy composite filament were tested.The CMPCF/TPU/epoxy composites are formed by 3D printing technology,and the composite filament is laid according to the direction of heat conduction so that the printed part can meet the needs of directional heat conduction.The experimental results show that the thermal conductivity of the printed sample is 40.549 W/(m·K),which is 160 times that of pure epoxy resin(0.254 W/(m·K)).It is also approximately 13 times better than that of polyacrylonitrile carbon fiber/epoxy(PAN-CF/epoxy)composites.This study breaks through the technical bottleneck of poor printability of CMPCF.It provides a new method for achieving directional thermal conductivity printing,which is important for the development of complex high-performance thermal conductivity products.
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financially supported by the National Key R&D Program of China(2023YFE0210800)National Natural Science Foundation of China(U21A2069,22305088)+4 种基金Natural Science Foundation of Hubei Province(JCZRQN202400929)Shenzhen Science and Technology Program(JCYJ20240813153403005,JCYJ20220818102215033)Guangdong Basic and Applied Basic Research Foundation(2023B1515120041)Open Research Fund of Suzhou Laboratory(SZLAB-1508-2024-ZD013)Guangdong HUST Industrial Technology Research Institute,Guangdong Provincial Key Laboratory of Manufacturing Equipment Digitization(2023B1212060012)。
文摘Fiber photodetectors(FPDs)with high deformability,flexible designability,and seamless integrability with everyday textiles hold tremendous potential for the nextgeneration wearable optoelectronics.Inorganic semiconductors(ISCs)are considered the ideal building block to design and govern the functions of FPDs owing to their superior electrical and optical properties.Recent developments in wearable technology of ISCs,especially in fiber form factor,have driven the creation of various FPDs with smart capabilities,from light sensing,information interfacing,to sophisticated logic operating,revolutionizing human-machine interaction paradigms in many emerging fields.Herein,we present a comprehensive review of the recent progress of ISCbased FPDs.Firstly,key design principles for ISC-based FPDs are explored,encompassing material selection,fabrication technologies,device architectures,and textile integration strategies.Then,how defect engineering,alignment engineering,and heterojunction engineering of ISCs can control the optoelectronic performance of FPDs is examined.Following this,potential wearable applications of ISC-based FPDs in optical communication,image sensing,and health monitoring are analyzed.Finally,the challenges and perspectives for the design of high-performance ISC-based FPDs are outlined.
基金supported by the Deutsche Forschungsgemeinschaft(DFG),TRR274(Project ID 408885537,Sy Nergy,EXC 2145/ID 390857198,to FMB)。
文摘The remodeling of axonal connections following injury is an important feature driving functional recovery.The reticulospinal tract is an interesting descending motor tract that contains both excitatory and inhibitory fibers.While the reticulospinal tract has been shown to be particularly prone to axonal growth and plasticity following injuries of the spinal cord,the differential capacities of excitatory and inhibitory fibers for plasticity remain unclear.As adaptive axonal plasticity involves a sophisticated interplay between excitatory and inhibitory input,we investigated in this study the plastic potential of glutamatergic(vGlut2)and GABAergic(vGat)fibers originating from the gigantocellular nucleus and the lateral paragigantocellular nucleus,two nuclei important for locomotor function.Using a combination of viral tracing,chemogenetic silencing,and AI-based kinematic analysis,we investigated plasticity and its impact on functional recovery within the first 3 weeks following injury,a period prone to neuronal remodeling.We demonstrate that,in this time frame,while vGlut2-positive fibers within the gigantocellular and lateral paragigantocellular nuclei rewire significantly following cervical spinal cord injury,vGat-positive fibers are rather unresponsive to injury.We also show that the acute silencing of excitatory axonal fibers which rewire in response to lesions of the spinal cord triggers a worsening of the functional recovery.Using kinematic analysis,we also pinpoint the locomotion features associated with the gigantocellular nucleus or lateral paragigantocellular nucleus during functional recovery.Overall,our study increases the understanding of the role of the gigantocellular and lateral paragigantocellular nuclei during functional recovery following spinal cord injury.
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supported by grants from the National Natural Science Foundation of China(32170271,32470277)the Natural Science Foundation of Henan Province(222300420024).
文摘Natural colored cotton(NCC)offers a sustainable,dye-free,and eco-friendly alternative for producing colored textiles.Carotenoids,a group of important natural liposoluble pigments,are known for their diverse color spectrum.In this study,we successfully engineered the carotenoid biosynthesis pathway specifically in cotton fibers by utilizing a fiber-specific GbEXPA2 promoter and a CaMV 35S promoter to drive the expression of two key carotenoid biosynthesis genes,CrtB and CrtI,respectively.This approach resulted in the development of a golden fiber cotton germplasm enriched withβ-carotene.Notably,the pigmentation was predominantly observed during the early developmental stages of the fiber(5–20 d post-anthesis).While the presence of carotenoids had no significant effect on plant architecture and growth,it positively influenced the fiber elongation rate,albeit with a slight reduction in fiber length and strength.This study represents a pioneering strategy for the future development of NCCs through carotenoid biofortification.
基金supported by the National Natural Science Foundation of China (Grant No. 5186504)the University Science Foundation for Young Science and Technology Talents in Inner Mongolia Autonomous Region of China (Grant No. NJYT22078)+2 种基金the Basic Scientific Research Expenses Program of Universities directly under Inner Mongolia Autonomous Region (Grant No. JY20220059)the Inner Mongolia Autonomous Region ‘Grassland Talent’ project Young Innovative Talent Training Program Level ⅠBasic Research Expenses of Universities directly under the Inner Mongolia Autonomous Region (Grant No. ZTY2023040)。
文摘To develop a suitable production process for fiber reinforced investment casting shell mold,three methods were studied:the traditional method(M_(1)),the method of adding fiber into silica sol with mechanical stirring and ultrasonic agitation(M_(2)),and the method of adding fiber into slurry with mechanical stirring and ultrasonic agitation for durations of 3,15,30,and 45 min(M_(3)).The bending strength,high-temperature self-load deformation,and thermal conductivity of the shell molds were investigated.The results reveal that the enhancement of fiber dispersion through ultrasonic agitation improves the comprehensive performance of the shell molds.The maximum green bending strength of the shell mold by M_(2) reaches 3.29 MPa,which is 29% higher than that of the shell mold prepared by M_(1).Moreover,the high-temperature self-load deformation of the shell mold is reduced from 0.62% to 0.44%.In addition,simultaneous ultrasonic agitation and mechanical stirring effectively shorten the slurry preparation time while maintaining comparable levels of fiber dispersion.With the process M_(3)-45 min,the fillers are uniformly dispersed in the slurry,and the fired bending strength and the high-temperature self-load deformation reach 6.25 MPa and 0.41%,respectively.Therefore,the proposed ultrasonic agitation route is promising for the fabrication of fiber-reinforced shell molds with excellent fibers dispersion.
基金financially supported by the Zhejiang Provincial Natural Science Foundation of China(LMS25E030001)the Fundamental Research Funds of Zhejiang Sci-Tech University(25212142-Y and 23212200-Y)。
文摘The development of high-performance bifunctional electrocatalysts is crucial for advancing zinc-air batteries.However,the fundamentally distinct mechanisms of the oxygen reduction and evolution reactions(ORR/OER)hinder the simultaneous realization of high activity within a single catalyst.Herein,we propose a spatial decoupling strategy to overcome this limitation by engineering isolated Fe singleatoms and Fe-Ir dual-atom pairs on a nitrogen-doped carbon matrix(Fe/FeIr-NC).In this architecture,Fe single atoms serve as ORR centers,while Fe-Ir pairs with tunable spacing are tailored for OER,enabling complete functional separation and independent optimization of the reactions.As a result,the catalyst delivers an ORR half-wave potential of 0.91 V and an OER overpotential of 250 mV at 10 mA cm^(-2),yielding a record-low bifunctional gap(ΔE=0.57 V)that outperforms all reported single-and dual-atom catalysts.A flexible fiber zincair battery was developed based on this catalyst,delivering a peak power density of 3920 W kg^(-1),along with a 1.4-fold increase in energy efficiency and a 2.6-fold extension in cycle life compared to the commercial Pt/C+IrO_(2)benchmark.This work not only breaks the traditional activity trade-off in bifunctional catalysis but also offers a promising route toward high-performance power sources for wearable electronics.
基金supported by the Opening Foundation of Hubei Key Laboratory for New Textile Materials and Applications Research(Grant No.FZXCL202410)the Key Project of Science and Technology Research Program of Hubei Provincial Department of Education,China(Grant No.D20231704)+1 种基金Wuhan Textile University(Grant No.523058)the Foundation of Wuhan Textile University(Grant No.K24058)。
文摘Materials exhibiting broadband nonlinear optical responses are critically important for ultrafast photonics applications,particularly as saturable absorbers(SAs)that facilitate broadband optical pulse generation.In this study,tea polyphenolpolyvinyl alcohol(TP-PVA)composite films are synthesized via a polymer embedding method and employed as SAs to initiate ultrafast pulse operation in fiber lasers.The TP-PVA SA film exhibits excellent broadband saturable absorption performance at wavelengths of 1.0μm,1.5μm,and 2.0μm,with modulation depths of 54.21%,41.41%,and 51.16%,respectively.Stable passively mode-locked pulses with pulse widths of 588 fs,419 fs,and 743 fs are generated in Yb-,Er-,and Tm-doped fiber lasers,respectively.This work confirms the effective performance of TP-PVA as a broadband SA,and establishes a foundation for the integration of novel and sustainable materials within ultrafast photonic systems.The approach paves the way for developing compact broadband ultrafast laser systems operating in the near-infrared spectral region.
基金support of her postdoctoral research at the GFZ Helmholtz Centre for Geosciences.P.Pan acknowledges the financial support of the National Natural Science Foundation of China(Grant No.52339001)H.Hofmann and Y.Ji acknowledge the financial support of the Helmholtz Association's Initiative and Networking Fund for the Helmholtz Young Investigator Group ARES(contract number VH-NG-1516).
文摘A multi-stage stress relaxation test was performed on a granodiorite sample to understand the deformation process prior to the macroscopic failure of brittle rocks,as well as the transient response during stress relaxation.Distributed optical fiber sensing was used to measure strains across the sample surface by helically wrapping the single-mode fiber around the cylindrical sample.Close agreement was observed between the circumferential strains obtained from the optical fibers and the extensometer.The reconstructed full-field strain contours show strain heterogeneity from the crack closure phase,and the strains in the later deformation phase are dominantly localized within the former high-strain zone.The Gini coefficient was used to quantify the degree of strain localization and shows an initial increase during the crack closure phase,a decrease during the linear elastic phase,and a subsequent increase during the post-yielding phase.This behavior corresponds to a process of initial localization from an imperfect boundary condition,homogenization,and eventual relocalization prior to the macroscopic failure of the sample.The transient strain rate decay during the stress relaxation phase was quantified using the p-value in the“Omori-like"power law function.A higher initial stress at the onset of relaxation results in a lower p-value,indicating a slower strain rate decay.As the sample approaches macroscopic failure,the lowest p-value shifts from the most damaged zone to adjacent areas,suggesting stress redistribution or crack propagation in deformed crystalline rocks under stress relaxation conditions.
基金supported by the Key Special Projects of the Ministry of Science and Technology(SQ2020YFF0404523)the North Anhui Soybean Advantageous Characteristic Industry Cluster Project(2023CYJQ013)+2 种基金the National Natural Science Foundation of China(32172162)the Key Genetic Technologies Research and Development Program of Hefei(2021GJ075)the Young Talents Program of Anhui Academy of Agricultural Science(QNYC-202122).
文摘Okara is produced in large quantities annually in China,but much of it is discarded due to its high content of indigestible dietary fiber(DF),contributing to significant environmental challenges.Recognizing the underexplored medicinal potential of DF,we developed an efficient fermentation method to enhance the bioavailability of okara fiber.In this study,Pediococcus acidilactici IFJ-1,which has strong enzymatic production capabilities and beneficial effects on gastrointestinal flora modulation,was selected to ferment okara.Results showed decreases in viscosity and particle size,optimized surface structure,improved thermal stability and hydration properties,and a significant increase in soluble DF content from 1.85%to 3.91%.To evaluate the physiological effects,hyperlipidemic mouse models were established and subjected to dietary interventions utilizing okara and fermented okara to measure changes in physicochemical parameters,gut microbiota composition,and lipid metabolism.The dietary intervention was effective,particularly in the fermented okara group,showing a 7.3%weight loss,improved blood lipids(triglycerides:‒39.8%,total cholesterol:‒12.8%,low-density lipoprotein cholesterol:‒34.2%,high-density lipoprotein cholesterol:+26.2%),and a 22.2%lower liver index.Gut microbiota analysis revealed that fermented okara positively modulated the microbial community by increasing the abundance of beneficial bacteria(e.g.,Bacteroidota)and reducing the abundance of obesity-associated bacteria(e.g.,Bacillota).Lipid metabolism profiling further demonstrated that fermented okara downregulated harmful lipids(e.g.,(O-acyl)-ω-hydroxy fatty acids,ceramides,and diacylglycerols)while upregulating beneficial phospholipids(e.g.,phosphatidylinositol,phosphatidylserine,phosphatidylethanolamine,lysophosphatidylinositol and lysophosphatidic acid).This study highlights a novel approach for enhancing DF utilization through fermentation,providing valuable insights into strategies for preventing obesity and metabolic diseases.
基金financial support provided by the National Natural Science Foundation of China(Grant No.12302472)the Science and Technology Support Program of Jiangsu Province(Grant No.BK20230874)+2 种基金the Aeronautical Science Fund(ASF)(Grant No.2023Z057052005)the Research Fund of State Key Laboratory of Mechanics and Control for Aerospace Structures(Nanjing University of Aeronautics and Astronautics)(Grant No.MCAS-I-0124G02)the funding received from Jiangsu Hanvo Safety Product Co.,Ltd。
文摘High-performance fiber fabrics and composites experienced transverse compression deformation at ultrahigh strain rates near the impact point when subjected to high-velocity impacts,which significantly affected their ballistic limits.In this paper,a fiber-scale experimental method for characterizing ultrahigh strain-rate transverse compression behavior was proposed.To begin with,in order to measure the extremely low stress and strain in small specimens,the conventional Hopkinson bar was reduced to the hundred-micron scale,thereby achieving wave impedance matching with single fibers.In addition,tangential and normal laser Doppler velocimetry(LDV)methods were employed to realize non-contact,high-precision,and high-speed axial velocity measurements of micron-scale incident and transmission bars,respectively.Meanwhile,a microscopic observation system was used to facilitate the installation of miniature fiber samples.The experimental setup and procedures were introduced,and the system accuracy was verified through sample-free loading tests based on one-dimensional stress wave propagation theory.Dynamic compression experiments on Graphene-UHMWPE fibers were carried out,followed by post-compression microstructural characterization via scanning electron microscopy(SEM).Results demonstrated that successful mechanical characterization was achieved at strain rates exceeding 105,an order of magnitude higher than the previously reported maximum rates.Furthermore,during the loading process,the fibers underwent uniform compression deformation while exhibiting pronounced strain-rate effects.This method offers a novel approach for dynamic mechanical characterization of microscale single fibers,enabling the development of comprehensive strain-ratedependent material models to guide the design of advanced composites and high-performance fibers.
基金supported by the National Key Research and Development Program of China(2023YFB3809800)the National Natural Science Foundation of China(52172249,52525601)+2 种基金the Chinese Academy of Sciences Talents Program(E2290701)the Jiangsu Province Talents Program(JSSCRC2023545)the Special Fund Project of Carbon Peaking Carbon Neutrality Science and Technology Innovation of Jiangsu Province(BE2022011).
文摘Flexible fiber sensors,However,traditional methods face challenges in fabricating low-cost,large-scale fiber sensors.In recent years,the thermal drawing process has rapidly advanced,offering a novel approach to flexible fiber sensors.Through the preform-tofiber manufacturing technique,a variety of fiber sensors with complex functionalities spanning from the nanoscale to kilometer scale can be automated in a short time.Examples include temperature,acoustic,mechanical,chemical,biological,optoelectronic,and multifunctional sensors,which operate on diverse sensing principles such as resistance,capacitance,piezoelectricity,triboelectricity,photoelectricity,and thermoelectricity.This review outlines the principles of the thermal drawing process and provides a detailed overview of the latest advancements in various thermally drawn fiber sensors.Finally,the future developments of thermally drawn fiber sensors are discussed.
基金Project supported by the Key Deployment Special Research Project of the Chinese Academy of Sciences(Grant No.PTYQ2022YZ0001)the National Natural Science Foundation of China(Grant Nos.62175255 and 62227822)the National Key Research and Development Program of China(Grant No.2021YFB3602602)。
文摘We develop an ultrafast Yb-fiber laser system based on eight-channel coherent beam combining utilizing commercially available rod-type Yb-fibers.To ensure good combining efficiency and long-term operation of the system at the attosecond laser facility under construction,we fully stabilize the phase,group-delay,and beam-pointing of the eight fiber channels.Especially,we propose a novel multi-step hill climbing method to control both group-delay and beam-pointing.At a repetition rate of 1 MHz,this laser system delivers 270-fs pulses with 1.18-k W average power(1.18-m J pulse energy).The average-power instability of the laser system running for 12 hours is 0.32%.
