Decreasing mode coupling coefficient(κ) is an effective approach to suppress the inter-core crosstalk. Therefore, we deploy a low index rod and rectangle trench in the middle of two neighboring cores to reduce κ so ...Decreasing mode coupling coefficient(κ) is an effective approach to suppress the inter-core crosstalk. Therefore, we deploy a low index rod and rectangle trench in the middle of two neighboring cores to reduce κ so that the overlap of electric field distribution can be suppressed. We also propose approximate analytical solution(AAS) for κ of two crosstalk suppression models, which are two cores with one low index rod deployed in the middle and two cores with one low index rectangle trench deployed in the middle. We then do some modification for the results obtained by AAS and the modified results are proved to agree well with that obtained by finite element method(FEM). Therefore, we can use the modified AAS to get inter-core crosstalk for abovementioned two models quickly.展开更多
Naturally degradable capsule provides a platform for sustained fragrance release.However,practical challenges such as low encapsulation efficiency and difficulty in sustained release are still limited in using fragran...Naturally degradable capsule provides a platform for sustained fragrance release.However,practical challenges such as low encapsulation efficiency and difficulty in sustained release are still limited in using fragranceloaded capsules.In this work,the natural materials sodium alginate and gelatine are dissolved and act as the aqueous phase,lavender is dissolved in caprylic/capric triglyceride(GTCC)as the oil phase,and SiO_(2) nanoparticles with neutralwettability as a solid emulsifier to form O/W Pickering emulsions simultaneously.Finally,multi-core capsules are prepared using the drop injection method with emulsions as templates.The results show that the capsules have been successfully prepared with a spherical morphology and multi-core structure,and the encapsulation rate of multi-core capsules can reach up to 99.6%.In addition,the multi-core capsules possess desirable sustained release performance,the cumulative sustained release rate of fragrance at 25℃over 49 days is only 32.5%.It is attributed to the significant protection of multi-core structure,Pickering emulsion nanoparticle membranes,and hydrogel network shell for encapsulated fragrance.This study is designed to deliver a new strategy for using sustained-release technology with fragrance in food,cosmetics,textiles,and other fields.展开更多
In this Letter, we propose two crosstalk-aware routing, core, and spectrum assignment （CA-RCSA） algorithms for spatial division multiplexing enabled elastic optical networks （SDM-EONs） with multi-core fibers. Firs...In this Letter, we propose two crosstalk-aware routing, core, and spectrum assignment （CA-RCSA） algorithms for spatial division multiplexing enabled elastic optical networks （SDM-EONs） with multi-core fibers. First, the RCSA problem is modeled, and then a metric, i.e., CA spectrum compactness （CASC）, is designed to measure the spectrum status in SDM-EONs. Based on CASC, we propose two CA-RCSA algorithms, the first-fit （FF） CASC algorithm and the random-fit （RF） CASC algorithm. Simulation results show that our proposed algorithms can achieve better performance than the baseline algorithm in terms of blocking probability and spectrum utilization, with FF-CASC providing the best performance.展开更多
Space-division multiplexing based on few-mode multi-core fiber(FM-MCF)technology is expected to break the Shannon limit of a single-mode fiber.However,an FM-MCF is compact,and it is difficult to couple the beam to eac...Space-division multiplexing based on few-mode multi-core fiber(FM-MCF)technology is expected to break the Shannon limit of a single-mode fiber.However,an FM-MCF is compact,and it is difficult to couple the beam to each fiber core.3D waveguide devices have the advantages of low insertion loss and low cross talk in separating various spatial paths of multi-core fibers.Designing a 3D waveguide device for an FM-MCF requires considering not only higher-order modes transmission,but also waveguide bending.We propose and demonstrate a 3D waveguide device fabricated by femtosecond laser direct writing for various spatial path separations in an FM-MCF.The 3D waveguide device couples the LP01 and LP11a modes to the FM-MCF with an insertion loss below 3 dB and cross talk between waveguides below-36 dB.To test the performance of the 3D waveguide device,we demonstrate four-channel multiplexing communication with two LP modes and two cores in a 1-km few-mode sevencore fiber.The bit error rate curves show that the different degrees of bending of the waveguides result in a difference of approximately 1 dB in the power penalty.Femtosecond laser direct writing fabrication enables 3D waveguide devices to support high-order LP modes transmission and further improves FM-MCF communication.展开更多
In this paper, the influencing factors that affect few-mode and multi core optical fiber channel are analyzed in a comprehensive way. The theoretical modeling and computer simulation of the information channel are car...In this paper, the influencing factors that affect few-mode and multi core optical fiber channel are analyzed in a comprehensive way. The theoretical modeling and computer simulation of the information channel are carried out and then the modeling scheme of few-mode multicore optical fiber channel based on non-uniform mode field distribution is put forward. The proposed modeling scheme can not only exponentially increases the system capacity through fewmode multi-core optical fiber channel, but has better transmission performance compared to the channel of the same type to the uniform channel revealing from the simulation results.展开更多
Real-time system timing analysis is crucial for estimating the worst-case execution time(WCET)of a program.To achieve this,static or dynamic analysis methods are used,along with targeted modeling of the actual hardwar...Real-time system timing analysis is crucial for estimating the worst-case execution time(WCET)of a program.To achieve this,static or dynamic analysis methods are used,along with targeted modeling of the actual hardware system.This literature review focuses on calculating WCET for multi-core processors,providing a survey of traditional methods used for static and dynamic analysis and highlighting the major challenges that arise from different program execution scenarios on multi-core platforms.This paper outlines the strengths and weaknesses of current methodologies and offers insights into prospective areas of research on multi-core analysis.By presenting a comprehensive analysis of the current state of research on multi-core processor analysis for WCET estimation,this review aims to serve as a valuable resource for researchers and practitioners in the field.展开更多
The fiber optic sensing technology provides data support in structural health monitoring of the macro facilities,including design,construction,and maintenance of bridges,tunnels,ports and other infrastructures.In this...The fiber optic sensing technology provides data support in structural health monitoring of the macro facilities,including design,construction,and maintenance of bridges,tunnels,ports and other infrastructures.In this paper,a distributed vibration sensing system is proved to be responsive to a single touch over a 1.8-m-long equivalent fiber segment,covering a vibration frequency from 5 Hz to 25 kHz.The sensing fiber was arranged as an S type layout on the bridge to recognize the standing state,windblown disturbance,and walking vibration.Moreover,the knocking and climbing events are recognized fiber laying spinning lines and hanging on the fences,respectively.The demonstration shows an accurate positioning and sensitive vibration monitoring applied on the automated three-dimensional(3D) printed bridge,which is applicable to all kinds of 3D printed facilities as intelligent sensory neuro-networks.展开更多
Iced transmission line galloping poses a significant threat to the safety and reliability of power systems,leading directly to line tripping,disconnections,and power outages.Existing early warning methods of iced tran...Iced transmission line galloping poses a significant threat to the safety and reliability of power systems,leading directly to line tripping,disconnections,and power outages.Existing early warning methods of iced transmission line galloping suffer from issues such as reliance on a single data source,neglect of irregular time series,and lack of attention-based closed-loop feedback,resulting in high rates of missed and false alarms.To address these challenges,we propose an Internet of Things(IoT)empowered early warning method of transmission line galloping that integrates time series data from optical fiber sensing and weather forecast.Initially,the method applies a primary adaptive weighted fusion to the IoT empowered optical fiber real-time sensing data and weather forecast data,followed by a secondary fusion based on a Back Propagation(BP)neural network,and uses the K-medoids algorithm for clustering the fused data.Furthermore,an adaptive irregular time series perception adjustment module is introduced into the traditional Gated Recurrent Unit(GRU)network,and closed-loop feedback based on attentionmechanism is employed to update network parameters through gradient feedback of the loss function,enabling closed-loop training and time series data prediction of the GRU network model.Subsequently,considering various types of prediction data and the duration of icing,an iced transmission line galloping risk coefficient is established,and warnings are categorized based on this coefficient.Finally,using an IoT-driven realistic dataset of iced transmission line galloping,the effectiveness of the proposed method is validated through multi-dimensional simulation scenarios.展开更多
Fiber-reinforced composites are an ideal material for the lightweight design of aerospace structures. Especially in recent years, with the rapid development of composite additive manufacturing technology, the design o...Fiber-reinforced composites are an ideal material for the lightweight design of aerospace structures. Especially in recent years, with the rapid development of composite additive manufacturing technology, the design optimization of variable stiffness of fiber-reinforced composite laminates has attracted widespread attention from scholars and industry. In these aerospace composite structures, numerous cutout panels and shells serve as access points for maintaining electrical, fuel, and hydraulic systems. The traditional fiber-reinforced composite laminate subtractive drilling manufacturing inevitably faces the problems of interlayer delamination, fiber fracture, and burr of the laminate. Continuous fiber additive manufacturing technology offers the potential for integrated design optimization and manufacturing with high structural performance. Considering the integration of design and manufacturability in continuous fiber additive manufacturing, the paper proposes linear and nonlinear filtering strategies based on the Normal Distribution Fiber Optimization (NDFO) material interpolation scheme to overcome the challenge of discrete fiber optimization results, which are difficult to apply directly to continuous fiber additive manufacturing. With minimizing structural compliance as the objective function, the proposed approach provides a strategy to achieve continuity of discrete fiber paths in the variable stiffness design optimization of composite laminates with regular and irregular holes. In the variable stiffness design optimization model, the number of candidate fiber laying angles in the NDFO material interpolation scheme is considered as design variable. The sensitivity information of structural compliance with respect to the number of candidate fiber laying angles is obtained using the analytical sensitivity analysis method. Based on the proposed variable stiffness design optimization method for complex perforated composite laminates, the numerical examples consider the variable stiffness design optimization of typical non-perforated and perforated composite laminates with circular, square, and irregular holes, and systematically discuss the number of candidate discrete fiber laying angles, discrete fiber continuous filtering strategies, and filter radius on structural compliance, continuity, and manufacturability. The optimized discrete fiber angles of variable stiffness laminates are converted into continuous fiber laying paths using a streamlined process for continuous fiber additive manufacturing. Meanwhile, the optimized non-perforated and perforated MBB beams after discrete fiber continuous treatment, are manufactured using continuous fiber co-extrusion additive manufacturing technology to verify the effectiveness of the variable stiffness fiber optimization framework proposed in this paper.展开更多
The increasing deployment of electronics in everyday life has generated great concerns regarding the effective disposal of waste from these components.Here,we focused on a facile sustainable and economical strategy to...The increasing deployment of electronics in everyday life has generated great concerns regarding the effective disposal of waste from these components.Here,we focused on a facile sustainable and economical strategy to provide ideas for this issue.This strategy relied on using appropriate mechanical treatment and sodium lignosulfonate coating to improve the dispersion and interfacial compatibility of bamboo fibers in poly(lactic acid).By optimising the particle size and concentration of sodium lignosulphonate,high value-added and green composites were prepared using sectional pressurization with a venting procedure.The treated composite displayed an ultra-smooth surface(roughness of 0.592 nm),impressive transient properties(disintegration and degradation behaviour after 30 d),and outstanding ultraviolet(UV)shielding properties(100%).These properties hold the promise of being an excellent substrate for electronic devices,especially for high-precision processing,transient electronics,and UV damage prevention.The satisfactory interfacial compatibility of the composites was confirmed by detailed characterisation regarding the related physicochemical properties.This investigation offers a sustainable approach for producing high value-added green composites from biomass and biomass-derived materials.展开更多
Long-period fiber gratings have the advantages of small size,corrosion resistance,anti-electro-magnetic interference,and high sensitivity,making them widely used in biomedicine,the power industry,and aerospace.This pa...Long-period fiber gratings have the advantages of small size,corrosion resistance,anti-electro-magnetic interference,and high sensitivity,making them widely used in biomedicine,the power industry,and aerospace.This paper develops a long-period fiber grating sensor based on periodic microchannels.First,a series of linear structures were etched in the cladding of a single-mode fiber by femtosecond laser microma-chining.Then,the laser-modified region was selectively eroded by selective chemical etching to obtain the periodic microchannel structure.Finally,the channels were filled with polydimethylsiloxane(PDMS)to im-prove the spectral quality.The experimental results show that the sensor has good sensitivity in the measure-ment of various parameters such as temperature,stress,refractive index(RI),and bending.It has a temperat-ure sensitivity of−55.19 pm/℃,a strain sensitivity of−3.19 pm/με,a maximum refractive index sensitivity of 540.28 nm/RIU,and a bending sensitivity of 2.65 dB/m^(-1).All of the measurement parameters show good lin-ear responses.The sensor has strong application prospects in the field of precision measurement and sensing.展开更多
Insufficient interfacial activity and poor wettability between fibers and matrix are the two main factors limiting the improvement of mechanical properties of Carbon Fiber Reinforced Plastics(CFRP).Owl feathers are kn...Insufficient interfacial activity and poor wettability between fibers and matrix are the two main factors limiting the improvement of mechanical properties of Carbon Fiber Reinforced Plastics(CFRP).Owl feathers are known for their unique compact structure;they are not only lightweight but also strong.In this study,an in-depth look at owl feathers was made and it found that owl feathers not only have the macro branches structure between feather shafts and branches but also have fine feather structures on the branches.The presence of these fine feather structures increases the specific surface area of the plume branches and allows neighboring plume branches to hook up with each other,forming an effective mechanical interlocking structure.These structures bring owl feathers excellent mechanical properties.Inspired by the natural structure of owl feathers,a weaving technique and a sizing process were combined to prepare bionic Carbon Fiber(CF)fabrics and then to fabricate the bionic CFRP with structural characteristics similar to owl feathers.To evaluate the effect of the fine feather structure on the mechanical properties of CFRP,a mechanical property study on CFRP with and without the fine feather imitation structure were conducted.The experimental results show that the introduction of the fine feather branch structure enhance the mechanical properties of CFRP significantly.Specifically,the tensile strength of the composites increased by 6.42%and 13.06%and the flexural strength increased by 8.02%and 16.87%in the 0°and 90°sample directions,respectively.These results provide a new design idea for the improvement of the mechanical properties of the CFRP,promoting the application of CFRP in engineering fields,such as automotive transportation,rail transit,aerospace,and construction.展开更多
Background There is a growing focus on using various plant-derived agricultural by-products to increase the benefits of pig farming,but these feedstuffs are fibrous in nature.This study investigated the relationship b...Background There is a growing focus on using various plant-derived agricultural by-products to increase the benefits of pig farming,but these feedstuffs are fibrous in nature.This study investigated the relationship between dietary fiber physicochemical properties and feedstuff fermentation characteristics and their effects on nutrient utilization,energy metabolism,and gut microbiota in growing pigs.Methods Thirty-six growing barrows(47.2±1.5 kg)were randomly allotted to 6 dietary treatments with 2 apparent viscosity levels and 3β-glucan-to-arabinoxylan ratios.In the experiment,nutrient utilization,energy metabolism,fecal microbial community,and production and absorption of short-chain fatty acid(SCFA)of pigs were investigated.In vitro digestion and fermentation models were used to compare the fermentation characteristics of feedstuffs and ileal digesta in the pig’s hindgut.Results The production dynamics of SCFA and dry matter corrected gas production of different feedstuffs during in vitro fermentation were different and closely related to the physical properties and chemical structure of the fiber.In animal experiments,increasing the dietary apparent viscosity and theβ-glucan-to-arabinoxylan ratios both increased the apparent ileal digestibility(AID),apparent total tract digestibility(ATTD),and hindgut digestibility of fiber components while decreasing the AID and ATTD of dry matter and organic matter(P<0.05).In addition,increasing dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios both increased gas exchange,heat production,and protein oxidation,and decreased energy deposition(P<0.05).The dietary apparent viscosity andβ-glucanto-arabinoxylan ratios had linear interaction effects on the digestible energy,metabolizable energy,retained energy(RE),and net energy(NE)of the diets(P<0.05).At the same time,the increase of dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios both increased SCFA production and absorption(P<0.05).Increasing the dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios increased the diversity and abundance of bacteria(P<0.05)and the relative abundance of beneficial bacteria.Furthermore,increasing the dietaryβ-glucan-to-arabinoxylan ratios led to a linear increase in SCFA production during the in vitro fermentation of ileal digesta(P<0.001).Finally,the prediction equations for RE and NE were established.Conclusion Dietary fiber physicochemical properties alter dietary fermentation patterns and regulate nutrient utilization,energy metabolism,and pig gut microbiota composition and metabolites.展开更多
Soft polymer optical fiber(SPOF)has shown great potential in optical-based wearable and implantable biosensors due to its excellent mechanical properties and optical guiding characteristics.However,the multimodality c...Soft polymer optical fiber(SPOF)has shown great potential in optical-based wearable and implantable biosensors due to its excellent mechanical properties and optical guiding characteristics.However,the multimodality characteristics of SPOF limit their integration with traditional fiber optic sensors.This article introduces for the first time a flexible fiber optic vibration sensor based on laser interference technology,which can be applied to vibration measurement under high stretch conditions.This sensor utilizes elastic optical fibers made of polydimethylsiloxane(PDMS)as sensing elements,combined with phase generating carrier technology,to achieve vibration measurement at 50−260 Hz within the stretch range of 0−42%.展开更多
In this paper,a double-effect DNN-based Digital Back-Propagation(DBP)scheme is proposed and studied to achieve the Integrated Communication and Sensing(ICS)ability,which can not only realize nonlinear damage mitigatio...In this paper,a double-effect DNN-based Digital Back-Propagation(DBP)scheme is proposed and studied to achieve the Integrated Communication and Sensing(ICS)ability,which can not only realize nonlinear damage mitigation but also monitor the optical power and dispersion profile over multi-span links.The link status information can be extracted by the characteristics of the learned optical fiber parameters without any other measuring instruments.The efficiency and feasibility of this method have been investigated in different fiber link conditions,including various launch power,transmission distance,and the location and the amount of the abnormal losses.A good monitoring performance can be obtained while the launch optical power is 2 dBm which does not affect the normal operation of the optical communication system and the step size of DBP is 20 km which can provide a better distance resolution.This scheme successfully detects the location of single or multiple optical attenuators in long-distance multi-span fiber links,including different abnormal losses of 2 dB,4 dB,and 6 dB in 360 km and serval combinations of abnormal losses of(1 dB,5 dB),(3 dB,3 dB),(5 dB,1 dB)in 360 km and 760 km.Meanwhile,the transfer relationship of the estimated coefficient values with different step sizes is further investigated to reduce the complexity of the fiber nonlinear damage compensation.These results provide an attractive approach for precisely sensing the optical fiber link status information and making correct strategies timely to ensure optical communication system operations.展开更多
A large mode area multi-core orbital angular momentum(OAM)transmission fiber is designed and optimized by neural network and optimization algorithms.The neural network model has been established first to predict the o...A large mode area multi-core orbital angular momentum(OAM)transmission fiber is designed and optimized by neural network and optimization algorithms.The neural network model has been established first to predict the optical properties of multi-core OAM transmission fibers with high accuracy and speed,including mode area,nonlinear coefficient,purity,dispersion,and effective index difference.Then the trained neural network model is combined with different particle swarm optimization(PSO)algorithms for automatic iterative optimization of multi-core structures respectively.Due to the structural advantages of multi-core fiber and the automatic optimization process,we designed a number of multi-core structures with high OAM mode purity(>95%)and ultra-large mode area(>3000µm^(2)),which is larger by more than an order of magnitude compared to the conventional ring-core OAM transmission fibers.展开更多
Aiming at the requirement for high-precision tilt monitoring in the field of structural health monitoring(SHM),this paper proposes a sensitivity-enhanced tilt sensor based on a femtosecond fiber Bragg grating(FBG).Fir...Aiming at the requirement for high-precision tilt monitoring in the field of structural health monitoring(SHM),this paper proposes a sensitivity-enhanced tilt sensor based on a femtosecond fiber Bragg grating(FBG).Firstly,structural design of the tilt sensor was conducted based on static mechanics principles.By positioning the FBG away from the beam’s neutral axis,linear strain enhancement in the FBG was achieved,thereby improving sensor sensitivity.The relationship between FBG strain,applied force,and the offset distance from the neutral axis was established,determining the optimal distance corresponding to maximum strain.Based on this optimization scheme,a prototype of the tilt sensor was designed,fabricated,and experimentally tested.Experimental results show that the FBG offset distance yielding maximum sensitivity is 4.4 mm.Within a tilt angle range of−30°to 30°,the sensor achieved a sensitivity of 129.95 pm/°and a linearity of 0.9997.Compared to conventional FBG-based tilt sensors,both sensitivity and linearity were significantly improved.Furthermore,the sensor demonstrated excellent repeatability(error<0.94%),creep resistance(error<0.30%),and temperature stability(error<0.90%).These results demonstrate the sensor’s excellent potential for SHM applications.The sensor has been successfully deployed in an underground pipeline project,conducting long-term monitoring of tilt and deformation in the steel support structures,further proving its value for engineering safety monitoring.展开更多
基金supported by National B a-sic Research Program of China(Grant No.2012CB315905)National Natural Science Foundation of China(Grant No.61501027)+1 种基金China Postdoctoral Science Foundation(Grant No.2015M570934)Fundamental Research Funds for the Central Universities(Grant No.FRF-TP-15-031A1)
文摘Decreasing mode coupling coefficient(κ) is an effective approach to suppress the inter-core crosstalk. Therefore, we deploy a low index rod and rectangle trench in the middle of two neighboring cores to reduce κ so that the overlap of electric field distribution can be suppressed. We also propose approximate analytical solution(AAS) for κ of two crosstalk suppression models, which are two cores with one low index rod deployed in the middle and two cores with one low index rectangle trench deployed in the middle. We then do some modification for the results obtained by AAS and the modified results are proved to agree well with that obtained by finite element method(FEM). Therefore, we can use the modified AAS to get inter-core crosstalk for abovementioned two models quickly.
文摘Naturally degradable capsule provides a platform for sustained fragrance release.However,practical challenges such as low encapsulation efficiency and difficulty in sustained release are still limited in using fragranceloaded capsules.In this work,the natural materials sodium alginate and gelatine are dissolved and act as the aqueous phase,lavender is dissolved in caprylic/capric triglyceride(GTCC)as the oil phase,and SiO_(2) nanoparticles with neutralwettability as a solid emulsifier to form O/W Pickering emulsions simultaneously.Finally,multi-core capsules are prepared using the drop injection method with emulsions as templates.The results show that the capsules have been successfully prepared with a spherical morphology and multi-core structure,and the encapsulation rate of multi-core capsules can reach up to 99.6%.In addition,the multi-core capsules possess desirable sustained release performance,the cumulative sustained release rate of fragrance at 25℃over 49 days is only 32.5%.It is attributed to the significant protection of multi-core structure,Pickering emulsion nanoparticle membranes,and hydrogel network shell for encapsulated fragrance.This study is designed to deliver a new strategy for using sustained-release technology with fragrance in food,cosmetics,textiles,and other fields.
基金supported by the National Natural Science Foundation of China(Nos.61571058 and 61501049)the National 863 Project of China(No.2015AA015503)+2 种基金the State Key Laboratory of Information Photonics and Optical Communications(Nos.IPOC2014ZZ03 and IPOC2015ZT01)the Chinese Scholarship Council(CSC),BUPT Excellent Ph.D.Students Foundation(No.CX2015307)the NSF Project(No.CNS-1302645).
文摘In this Letter, we propose two crosstalk-aware routing, core, and spectrum assignment （CA-RCSA） algorithms for spatial division multiplexing enabled elastic optical networks （SDM-EONs） with multi-core fibers. First, the RCSA problem is modeled, and then a metric, i.e., CA spectrum compactness （CASC）, is designed to measure the spectrum status in SDM-EONs. Based on CASC, we propose two CA-RCSA algorithms, the first-fit （FF） CASC algorithm and the random-fit （RF） CASC algorithm. Simulation results show that our proposed algorithms can achieve better performance than the baseline algorithm in terms of blocking probability and spectrum utilization, with FF-CASC providing the best performance.
基金Guangdong Major Project of Basic Research(2020B0301030009)National Key Research and Development Program of China(2018YFB1801801,2018YFB1800901)+4 种基金National Natural Science Foundation of China(61935013,61975133,62075139,61705135,12047540,61835005,62175162,62105215)Natural Science Foundation of Guangdong Province(2020A1515011185)Science,Technology and Innovation Commission of Shenzhen Municipality(RCJC20200714114435063,KQJSCX20170727100838364,JCYJ20180507182035270,JCYJ20200109114018750)Shenzhen Peacock Plan(KQTD20170330110444030)Shenzhen University(2019075)。
文摘Space-division multiplexing based on few-mode multi-core fiber(FM-MCF)technology is expected to break the Shannon limit of a single-mode fiber.However,an FM-MCF is compact,and it is difficult to couple the beam to each fiber core.3D waveguide devices have the advantages of low insertion loss and low cross talk in separating various spatial paths of multi-core fibers.Designing a 3D waveguide device for an FM-MCF requires considering not only higher-order modes transmission,but also waveguide bending.We propose and demonstrate a 3D waveguide device fabricated by femtosecond laser direct writing for various spatial path separations in an FM-MCF.The 3D waveguide device couples the LP01 and LP11a modes to the FM-MCF with an insertion loss below 3 dB and cross talk between waveguides below-36 dB.To test the performance of the 3D waveguide device,we demonstrate four-channel multiplexing communication with two LP modes and two cores in a 1-km few-mode sevencore fiber.The bit error rate curves show that the different degrees of bending of the waveguides result in a difference of approximately 1 dB in the power penalty.Femtosecond laser direct writing fabrication enables 3D waveguide devices to support high-order LP modes transmission and further improves FM-MCF communication.
基金supports from National High Technology 863 Program of China(No.2013AA013403,2015AA015501,2015AA015502,2015AA015504)National NSFC(No.61425022/61522501/61307086/61475024/61275158/61201151/61275074/61372109)+4 种基金Beijing Nova Program(No.Z141101001814048)Beijing Excellent Ph.D.Thesis Guidance Foundation(No.20121001302)the Universities Ph.D.Special Research Funds(No.20120005110003/20120005120007)Fund of State Key Laboratory of IPOC(BUPT)P.R.China
文摘In this paper, the influencing factors that affect few-mode and multi core optical fiber channel are analyzed in a comprehensive way. The theoretical modeling and computer simulation of the information channel are carried out and then the modeling scheme of few-mode multicore optical fiber channel based on non-uniform mode field distribution is put forward. The proposed modeling scheme can not only exponentially increases the system capacity through fewmode multi-core optical fiber channel, but has better transmission performance compared to the channel of the same type to the uniform channel revealing from the simulation results.
基金supported by ZTE Industry-University-Institute Cooperation Funds under Grant No.2022ZTE09.
文摘Real-time system timing analysis is crucial for estimating the worst-case execution time(WCET)of a program.To achieve this,static or dynamic analysis methods are used,along with targeted modeling of the actual hardware system.This literature review focuses on calculating WCET for multi-core processors,providing a survey of traditional methods used for static and dynamic analysis and highlighting the major challenges that arise from different program execution scenarios on multi-core platforms.This paper outlines the strengths and weaknesses of current methodologies and offers insights into prospective areas of research on multi-core analysis.By presenting a comprehensive analysis of the current state of research on multi-core processor analysis for WCET estimation,this review aims to serve as a valuable resource for researchers and practitioners in the field.
基金supported by the National Natural Science Foundation of China (No.6210031560)the Natural Science Foundation of Hebei Province (No.A2020202013)the Natural Science Foundation of Tianjin City (No.21JCQNJC00780)。
文摘The fiber optic sensing technology provides data support in structural health monitoring of the macro facilities,including design,construction,and maintenance of bridges,tunnels,ports and other infrastructures.In this paper,a distributed vibration sensing system is proved to be responsive to a single touch over a 1.8-m-long equivalent fiber segment,covering a vibration frequency from 5 Hz to 25 kHz.The sensing fiber was arranged as an S type layout on the bridge to recognize the standing state,windblown disturbance,and walking vibration.Moreover,the knocking and climbing events are recognized fiber laying spinning lines and hanging on the fences,respectively.The demonstration shows an accurate positioning and sensitive vibration monitoring applied on the automated three-dimensional(3D) printed bridge,which is applicable to all kinds of 3D printed facilities as intelligent sensory neuro-networks.
基金research was funded by Science and Technology Project of State Grid Corporation of China under grant number 5200-202319382A-2-3-XG.
文摘Iced transmission line galloping poses a significant threat to the safety and reliability of power systems,leading directly to line tripping,disconnections,and power outages.Existing early warning methods of iced transmission line galloping suffer from issues such as reliance on a single data source,neglect of irregular time series,and lack of attention-based closed-loop feedback,resulting in high rates of missed and false alarms.To address these challenges,we propose an Internet of Things(IoT)empowered early warning method of transmission line galloping that integrates time series data from optical fiber sensing and weather forecast.Initially,the method applies a primary adaptive weighted fusion to the IoT empowered optical fiber real-time sensing data and weather forecast data,followed by a secondary fusion based on a Back Propagation(BP)neural network,and uses the K-medoids algorithm for clustering the fused data.Furthermore,an adaptive irregular time series perception adjustment module is introduced into the traditional Gated Recurrent Unit(GRU)network,and closed-loop feedback based on attentionmechanism is employed to update network parameters through gradient feedback of the loss function,enabling closed-loop training and time series data prediction of the GRU network model.Subsequently,considering various types of prediction data and the duration of icing,an iced transmission line galloping risk coefficient is established,and warnings are categorized based on this coefficient.Finally,using an IoT-driven realistic dataset of iced transmission line galloping,the effectiveness of the proposed method is validated through multi-dimensional simulation scenarios.
基金supports for this research were provided by the National Natural Science Foundation of China(No.12272301,12002278,U1906233)the Guangdong Basic and Applied Basic Research Foundation,China(Nos.2023A1515011970,2024A1515010256)+1 种基金the Dalian City Supports Innovation and Entrepreneurship Projects for High-Level Talents,China(2021RD16)the Key R&D Project of CSCEC,China(No.CSCEC-2020-Z-4).
文摘Fiber-reinforced composites are an ideal material for the lightweight design of aerospace structures. Especially in recent years, with the rapid development of composite additive manufacturing technology, the design optimization of variable stiffness of fiber-reinforced composite laminates has attracted widespread attention from scholars and industry. In these aerospace composite structures, numerous cutout panels and shells serve as access points for maintaining electrical, fuel, and hydraulic systems. The traditional fiber-reinforced composite laminate subtractive drilling manufacturing inevitably faces the problems of interlayer delamination, fiber fracture, and burr of the laminate. Continuous fiber additive manufacturing technology offers the potential for integrated design optimization and manufacturing with high structural performance. Considering the integration of design and manufacturability in continuous fiber additive manufacturing, the paper proposes linear and nonlinear filtering strategies based on the Normal Distribution Fiber Optimization (NDFO) material interpolation scheme to overcome the challenge of discrete fiber optimization results, which are difficult to apply directly to continuous fiber additive manufacturing. With minimizing structural compliance as the objective function, the proposed approach provides a strategy to achieve continuity of discrete fiber paths in the variable stiffness design optimization of composite laminates with regular and irregular holes. In the variable stiffness design optimization model, the number of candidate fiber laying angles in the NDFO material interpolation scheme is considered as design variable. The sensitivity information of structural compliance with respect to the number of candidate fiber laying angles is obtained using the analytical sensitivity analysis method. Based on the proposed variable stiffness design optimization method for complex perforated composite laminates, the numerical examples consider the variable stiffness design optimization of typical non-perforated and perforated composite laminates with circular, square, and irregular holes, and systematically discuss the number of candidate discrete fiber laying angles, discrete fiber continuous filtering strategies, and filter radius on structural compliance, continuity, and manufacturability. The optimized discrete fiber angles of variable stiffness laminates are converted into continuous fiber laying paths using a streamlined process for continuous fiber additive manufacturing. Meanwhile, the optimized non-perforated and perforated MBB beams after discrete fiber continuous treatment, are manufactured using continuous fiber co-extrusion additive manufacturing technology to verify the effectiveness of the variable stiffness fiber optimization framework proposed in this paper.
基金supported by the National Natural Science Foundation of China(Nos.31971741 and 31760195)the Yunnan Fundamental Research Projects(Nos.2018FB066 and 202001AT070141)the Yunnan Agricultural Basic Research Special Projects(No.202101BD070001-086).
文摘The increasing deployment of electronics in everyday life has generated great concerns regarding the effective disposal of waste from these components.Here,we focused on a facile sustainable and economical strategy to provide ideas for this issue.This strategy relied on using appropriate mechanical treatment and sodium lignosulfonate coating to improve the dispersion and interfacial compatibility of bamboo fibers in poly(lactic acid).By optimising the particle size and concentration of sodium lignosulphonate,high value-added and green composites were prepared using sectional pressurization with a venting procedure.The treated composite displayed an ultra-smooth surface(roughness of 0.592 nm),impressive transient properties(disintegration and degradation behaviour after 30 d),and outstanding ultraviolet(UV)shielding properties(100%).These properties hold the promise of being an excellent substrate for electronic devices,especially for high-precision processing,transient electronics,and UV damage prevention.The satisfactory interfacial compatibility of the composites was confirmed by detailed characterisation regarding the related physicochemical properties.This investigation offers a sustainable approach for producing high value-added green composites from biomass and biomass-derived materials.
文摘Long-period fiber gratings have the advantages of small size,corrosion resistance,anti-electro-magnetic interference,and high sensitivity,making them widely used in biomedicine,the power industry,and aerospace.This paper develops a long-period fiber grating sensor based on periodic microchannels.First,a series of linear structures were etched in the cladding of a single-mode fiber by femtosecond laser microma-chining.Then,the laser-modified region was selectively eroded by selective chemical etching to obtain the periodic microchannel structure.Finally,the channels were filled with polydimethylsiloxane(PDMS)to im-prove the spectral quality.The experimental results show that the sensor has good sensitivity in the measure-ment of various parameters such as temperature,stress,refractive index(RI),and bending.It has a temperat-ure sensitivity of−55.19 pm/℃,a strain sensitivity of−3.19 pm/με,a maximum refractive index sensitivity of 540.28 nm/RIU,and a bending sensitivity of 2.65 dB/m^(-1).All of the measurement parameters show good lin-ear responses.The sensor has strong application prospects in the field of precision measurement and sensing.
基金supported by the Science and Technology Development Program of Jilin Province(No.20240101122JC)and(No.20240101143JC)the Key Scientific and Technological Research and Development Projects of Jilin Provincial Science and Technology Department(Grant Number 20230201108GX)。
文摘Insufficient interfacial activity and poor wettability between fibers and matrix are the two main factors limiting the improvement of mechanical properties of Carbon Fiber Reinforced Plastics(CFRP).Owl feathers are known for their unique compact structure;they are not only lightweight but also strong.In this study,an in-depth look at owl feathers was made and it found that owl feathers not only have the macro branches structure between feather shafts and branches but also have fine feather structures on the branches.The presence of these fine feather structures increases the specific surface area of the plume branches and allows neighboring plume branches to hook up with each other,forming an effective mechanical interlocking structure.These structures bring owl feathers excellent mechanical properties.Inspired by the natural structure of owl feathers,a weaving technique and a sizing process were combined to prepare bionic Carbon Fiber(CF)fabrics and then to fabricate the bionic CFRP with structural characteristics similar to owl feathers.To evaluate the effect of the fine feather structure on the mechanical properties of CFRP,a mechanical property study on CFRP with and without the fine feather imitation structure were conducted.The experimental results show that the introduction of the fine feather branch structure enhance the mechanical properties of CFRP significantly.Specifically,the tensile strength of the composites increased by 6.42%and 13.06%and the flexural strength increased by 8.02%and 16.87%in the 0°and 90°sample directions,respectively.These results provide a new design idea for the improvement of the mechanical properties of the CFRP,promoting the application of CFRP in engineering fields,such as automotive transportation,rail transit,aerospace,and construction.
基金supported by the National Key Research and Development Program(No.2021YFD1300201)Jilin Provincial Department of Science and Technology Innovation Platform and Talent Special Project(No.20230508090RC).
文摘Background There is a growing focus on using various plant-derived agricultural by-products to increase the benefits of pig farming,but these feedstuffs are fibrous in nature.This study investigated the relationship between dietary fiber physicochemical properties and feedstuff fermentation characteristics and their effects on nutrient utilization,energy metabolism,and gut microbiota in growing pigs.Methods Thirty-six growing barrows(47.2±1.5 kg)were randomly allotted to 6 dietary treatments with 2 apparent viscosity levels and 3β-glucan-to-arabinoxylan ratios.In the experiment,nutrient utilization,energy metabolism,fecal microbial community,and production and absorption of short-chain fatty acid(SCFA)of pigs were investigated.In vitro digestion and fermentation models were used to compare the fermentation characteristics of feedstuffs and ileal digesta in the pig’s hindgut.Results The production dynamics of SCFA and dry matter corrected gas production of different feedstuffs during in vitro fermentation were different and closely related to the physical properties and chemical structure of the fiber.In animal experiments,increasing the dietary apparent viscosity and theβ-glucan-to-arabinoxylan ratios both increased the apparent ileal digestibility(AID),apparent total tract digestibility(ATTD),and hindgut digestibility of fiber components while decreasing the AID and ATTD of dry matter and organic matter(P<0.05).In addition,increasing dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios both increased gas exchange,heat production,and protein oxidation,and decreased energy deposition(P<0.05).The dietary apparent viscosity andβ-glucanto-arabinoxylan ratios had linear interaction effects on the digestible energy,metabolizable energy,retained energy(RE),and net energy(NE)of the diets(P<0.05).At the same time,the increase of dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios both increased SCFA production and absorption(P<0.05).Increasing the dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios increased the diversity and abundance of bacteria(P<0.05)and the relative abundance of beneficial bacteria.Furthermore,increasing the dietaryβ-glucan-to-arabinoxylan ratios led to a linear increase in SCFA production during the in vitro fermentation of ileal digesta(P<0.001).Finally,the prediction equations for RE and NE were established.Conclusion Dietary fiber physicochemical properties alter dietary fermentation patterns and regulate nutrient utilization,energy metabolism,and pig gut microbiota composition and metabolites.
文摘Soft polymer optical fiber(SPOF)has shown great potential in optical-based wearable and implantable biosensors due to its excellent mechanical properties and optical guiding characteristics.However,the multimodality characteristics of SPOF limit their integration with traditional fiber optic sensors.This article introduces for the first time a flexible fiber optic vibration sensor based on laser interference technology,which can be applied to vibration measurement under high stretch conditions.This sensor utilizes elastic optical fibers made of polydimethylsiloxane(PDMS)as sensing elements,combined with phase generating carrier technology,to achieve vibration measurement at 50−260 Hz within the stretch range of 0−42%.
基金supported by the National Key Research and Development Program of China (2019YFB1803905)the National Natural Science Foundation of China (No.62171022)+2 种基金Beijing Natural Science Foundation (4222009)Guangdong Basic and Applied Basic Research Foundation (2021B1515120057)the Scientific and Technological Innovation Foundation of Shunde Graduate School,USTB (No.BK19AF005)。
文摘In this paper,a double-effect DNN-based Digital Back-Propagation(DBP)scheme is proposed and studied to achieve the Integrated Communication and Sensing(ICS)ability,which can not only realize nonlinear damage mitigation but also monitor the optical power and dispersion profile over multi-span links.The link status information can be extracted by the characteristics of the learned optical fiber parameters without any other measuring instruments.The efficiency and feasibility of this method have been investigated in different fiber link conditions,including various launch power,transmission distance,and the location and the amount of the abnormal losses.A good monitoring performance can be obtained while the launch optical power is 2 dBm which does not affect the normal operation of the optical communication system and the step size of DBP is 20 km which can provide a better distance resolution.This scheme successfully detects the location of single or multiple optical attenuators in long-distance multi-span fiber links,including different abnormal losses of 2 dB,4 dB,and 6 dB in 360 km and serval combinations of abnormal losses of(1 dB,5 dB),(3 dB,3 dB),(5 dB,1 dB)in 360 km and 760 km.Meanwhile,the transfer relationship of the estimated coefficient values with different step sizes is further investigated to reduce the complexity of the fiber nonlinear damage compensation.These results provide an attractive approach for precisely sensing the optical fiber link status information and making correct strategies timely to ensure optical communication system operations.
基金supported by the National Natural Science Foundation of China(Nos.92048301,62020106004 and 11704283)in part by the Tianjin Municipal Education Commission(No.2018KJ146)in part by the Opening Foundation of Tianjin Key Laboratory of Optoelectronic Detection Technology and Systems(No.2019LODTS004).
文摘A large mode area multi-core orbital angular momentum(OAM)transmission fiber is designed and optimized by neural network and optimization algorithms.The neural network model has been established first to predict the optical properties of multi-core OAM transmission fibers with high accuracy and speed,including mode area,nonlinear coefficient,purity,dispersion,and effective index difference.Then the trained neural network model is combined with different particle swarm optimization(PSO)algorithms for automatic iterative optimization of multi-core structures respectively.Due to the structural advantages of multi-core fiber and the automatic optimization process,we designed a number of multi-core structures with high OAM mode purity(>95%)and ultra-large mode area(>3000µm^(2)),which is larger by more than an order of magnitude compared to the conventional ring-core OAM transmission fibers.
文摘Aiming at the requirement for high-precision tilt monitoring in the field of structural health monitoring(SHM),this paper proposes a sensitivity-enhanced tilt sensor based on a femtosecond fiber Bragg grating(FBG).Firstly,structural design of the tilt sensor was conducted based on static mechanics principles.By positioning the FBG away from the beam’s neutral axis,linear strain enhancement in the FBG was achieved,thereby improving sensor sensitivity.The relationship between FBG strain,applied force,and the offset distance from the neutral axis was established,determining the optimal distance corresponding to maximum strain.Based on this optimization scheme,a prototype of the tilt sensor was designed,fabricated,and experimentally tested.Experimental results show that the FBG offset distance yielding maximum sensitivity is 4.4 mm.Within a tilt angle range of−30°to 30°,the sensor achieved a sensitivity of 129.95 pm/°and a linearity of 0.9997.Compared to conventional FBG-based tilt sensors,both sensitivity and linearity were significantly improved.Furthermore,the sensor demonstrated excellent repeatability(error<0.94%),creep resistance(error<0.30%),and temperature stability(error<0.90%).These results demonstrate the sensor’s excellent potential for SHM applications.The sensor has been successfully deployed in an underground pipeline project,conducting long-term monitoring of tilt and deformation in the steel support structures,further proving its value for engineering safety monitoring.
