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中国科学:技术科学（英文版）
中国科学:技术科学（英文版）

周光召

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1674-7321

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中国科学:技术科学（英文版）/Journal Science China Technological SciencesCSCDCSTPCDEISCI
查看更多>>《中国科学》是中国科学院主办、中国科学杂志社出版的自然科学专业性学术刊物。《中国科学》任务是反映中国自然科学各学科中的最新科研成果，以促进国内外的学术交流。《中国科学》以论文形式报道中国基础研究和应用研究方面具有创造性的、高水平的和有重要意义的科研成果。在国际学术界，《中国科学》作为代表中国最高水平的学术刊物也受到高度重视。国际上最具有权威的检索刊物SCI，多年来一直收录《中国科学》的论文。1999年《中国科学》夺得国家期刊奖的第一名。
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    An improved numerical model for evaporation with multicomponent gas

    PENG CanXU XiangHuaLIANG XinGangDENG Xiong...
    3443-3449页
    查看更多>>摘要：Evaporation is a key process in a wide range of industrial applications.To gain a better insight into this process,investigation on the evaporation model is an important aspect.In the present study,it is found that the computation with the Hertz-Knudsen-Schrage model is not easy to converge in the numerical simulation of the evaporation with multicomponent gas.The reason for the divergence is that the Hertz-Knudsen-Schrage model will lead to an improper vapor mass fraction which is much larger than the saturated vapor mass fraction in the iterations.To improve the convergence performance,an improved model for evaporation with multicomponent gas is proposed.In the improved evaporation model,when the predicted vapor density is larger than the saturated vapor density,a strategy that calculates the volumetric mass transfer rate with the difference between the saturated vapor density and the current vapor density will be implemented.As a result,the vapor density is bounded by the saturated values and no improper large vapor mass fraction arises in the iterations.The improved evaporation model shows much better convergence performance.In the case of the present study,the improved evaporation model can converge with the time step of 5×10-6s,while the original Hertz-Knudsen-Schrage model cannot converge with the time step of 5×10-9 s.The improved evaporation model is also compared with the empirical correlations and shows a good agreement.
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    Energy-efficient intermittent liquid heating of lithium-ion batteries in extreme cold using phase change materials

    LI KaiXuanZHANG JingShuYAO XiaoLeHUANG ZiZe...
    3450-3464页
    查看更多>>摘要：The electrochemical performance of lithium-ion batteries significantly deteriorates in extreme cold.Thus,to ensure battery safety under various conditions,various heating and insulation strategies are implemented.The present study proposes a hybrid heating approach combining active heating with passive insulation.Conceptual experiments were conducted to investigate the effects of phase change materials(PCMs),inlet water temperature,and intermittent pump startup strategies on battery perfor-mance.The obtained experimental results demonstrate that low temperatures lead to increased electrochemical impedance and reduced charge-discharge capacity in batteries.Notably,charge transfer resistance of 162 mΩ was observed at-30℃.Herein,the developed PCM-based battery heating system effectively extended the operational capacity of batteries in cold driving conditions and maintained battery warmth by leveraging the superior heat storage capability of the PCM.Additionally,after the switch off of the heating system,the charge capacity of the battery exceeded 80％owing to latent heat.The use of an intermittent heating strategy not only allowed to conserve energy but also maintained adequate heat storage within the battery module.At-30℃,this strategy enhanced the power efficiency of the cooling system by 35.94％with a reduction in capacity of only 0.8％compared to the continuous strategy.
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    A novel cylindrical sandwich plate inspired by beetle elytra and its compressive properties

    SONG YiHengRUAN SiHanHAO NingOKABE YoJi...
    3465-3476页
    查看更多>>摘要：The design and experimental analysis of a semi-cylindrical structure known as the cylindrical beetle elytron plate(CBEP)were presented.Radial compression tests and finite element simulation were performed on CBEPs under 30° and 45° inclined sliding support constraints,with a comparison made to cylindrical honeycomb plate(CHP).The study aims to investigate the superior compression performance and enhancement mechanisms of CBEPs.The results demonstrate that CBEPs exhibit a 14％-26％increase in specific load-bearing capacity and a 20％increase in specific energy absorption compared with CHPs with equal core wall thickness.Distinct"Z-shaped"tearing failures were observed,with honeycomb plates showing tearing at the center of the honeycomb walls,while beetle elytron plates exhibited tearing along the midline of the trabeculae.Three different stress patterns,including elastic-plastic development stage of arch,plastic hinge node stage,and rigid node stage,were identified and analyzed to explain the mechanical performance improvements and failure characteristics.Considering that structural damage to trabe-culae mostly occurs at its junction with the skin,it is recommended to add chamfers to the junctions of CBEP.Therefore,this paper lays the groundwork for the engineering application of CBEP.
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    Enhanced back-illuminated Ga2O3-based solar-blind ultraviolet photodetectors

    YAN ZuYongZHI YuSongJI XueQiangYUE JianYing...
    3477-3484页
    查看更多>>摘要：Ga2O3 is a promising material for deep-ultraviolet(DUV)photodetectors due to its ultra-wide bandgap and high thermal and chemical stability.However,because of their relatively low responsivity,Ga2O3-based photodetectors still have difficulty meeting the requirements of practical applications.Here,we construct a high-performance Ga2O3 photodetector realized by back-illumination.Utilizing high-crystallinity epitaxially grown Ga2O3 as the DUV absorbing layer and the double-polished A12O3 substrate as the transparent window for injection of photons,the device operating in the back-illuminated mode exhibits a higher DUV photoresponse and faster response speed than in the front-illuminated mode.Therefore,our experimental results have led to the development of a novel strategy for designing and fabricating high-performance Ga2O3 photodetectors.
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    Three-dimensional simulation of the coupled electromagnetic-mechanical responses in a no-insulation racetrack coil

    LI DongKeCHANG ZhiXiangTANG YunKaiLIU DongHui...
    3485-3498页
    查看更多>>摘要：This study investigates the coupled behavior of the mechanical and electromagnetic responses of a high-temperature super-conducting(HTS)no-insulation(NI)racetrack coil.A three-dimensional(3D)equivalent circuit network model and mechanical model with nonlinear contact are incorporated into the coupled model.The stress and separation of adjacent turns under a high magnetic field are analyzed by considering the electromagnetic force and cooling process.The numerical results demonstrate that the straight and curved parts of the racetrack coil exhibit distinct mechanical behaviors.Under a strong external magnetic field,the separation between adjacent turns reduces the charging delay of the coil.The maximum stress occurs in the transition regions between the curved and straight parts.The straight part exhibits a larger rotation angle,while the separation regions between adjacent turns are relatively fewer in those parts.The curved part shows a higher proportion of separation regions in the steady stage.The different separation areas in the straight and curved parts also result in distinct turn-to-turn losses during the charging process.Subsequently,a comparative study is conducted on the influence of residual currents induced by discharging.Finally,the effects of overband and inner diameter on the separation behavior are investigated.
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    A reduced graphene oxide-coated conductive surgical silk suture targeting microresistance sensing changes for wound healing

    DING YuQiWANG XuChenLIU JingGeSHEN HongQiang...
    3499-3512页
    查看更多>>摘要：Conventional sutures used in surgical procedures often lack the capability to effectively monitor physical and chemical activities or the microbial environment of surgical wounds due to their inadequate mechanical properties,insufficient electrical accuracy and unstability.Here,we present a straightforward layer-by-layer coating technique that utilizes 3-glycidoxypropyltrimethox-ysilane(CA),graphene oxide(GO),and ascorbic acid(AA)to develop conductive silk-based surgical sutures(CA-rGSFS).The CA-rGSFS feature a continuous reduced graphene oxide(rGO)film on their surface,forming robust hydrogen bonds with silk fibroin.The reduction process of rGO is confirmed through Raman analysis,demonstrating an enhanced D peak to G peak ratio.Notably,the CA-rGSFS exhibit exceptional mechanical properties and efficient electron transmission,with a knot-pull tensile strength of 2089.72±1.20 cN and an electrical conductivity of 130.30±11.34 S/m,respectively,meeting the requirements specified by the United States Pharmacopeia(USP)for 2-0 sutures.These novel CA-rGSFS demonstrate the ability to accurately track resistance changes in various fluid environments with rapid response,including saline,intestinal,and gastric fluids.The suture also retains remarkable stretchablility and stability even after enduring 3000 tensile cycles,highlighting their potential for precise surgical site monitoring during the wound healing process.
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    Coupling stiffening effect of carbon nanotubes on modulus of nanograined metals:Mechanism and multiscale modeling

    WANG FeiLI LiWANG XueLinHU YuJin...
    3513-3523页
    查看更多>>摘要：A quantitative relationship between grain size and Young's modulus of metal composites has not been established by considering the coupling effect of the reinforcements on microstructural deformation.The objective of this study is to investigate the mech-anism of deformation coordination between the carbon nanotube and the composite microstructure using molecular dynamics simulations.Through the analysis of stress contributions from grain boundaries and grains,a grain size-dependent continuum model for the pure metal modulus is established.On this basis,a predictive model for the modulus of metallic composites is developed by considering the coupling deformation between carbon nanotubes and the grains.The proposed model is capable of accurately capturing the relationship between grain size and the modulus of metal composites.This study provides a guideline for microstructure-dependent multiscale modeling.
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    Construction of laser-induced graphene/silver nanowire composite structures for low-strain,high-sensitivity flexible wearable strain sensors

    YANG PingAnZHAO JingYuanLI RuiZHOU ZhiHao...
    3524-3534页
    查看更多>>摘要：Sandwich-structured flexible sensors based on graphene have high sensitivity and stability.When graphene is combined with a flexible substrate in a sandwich structure,the weak bonding between them compromises the sensor's stability and sensitivity at low strains.This presents challenges in monitoring subtle physiological activities,such as hand bending and pulse rate.For this purpose,laser-induced graphene(LIG)is proposed to be used to prepare flexible sensors in order to improve the sensitivity and stability of the sensors at low strains.Polydimethylsiloxane(PDMS)with low modulus and polyimide(PI)with rich carbon content are selected as precursor materials for LIG,and graphene is formed through laser induction.Subsequently,silver nanowires(Ag NWs)solution is added to LIG to give the sensor low strain and high sensitivity performance.When the PI/PDMS ratio is 1:3,the Ag NWs/LIG flexible strain sensor exhibits excellent sensitivity(GF=778.468)over a small strain range(8.76％-11.25％).Meanwhile,the sensor still shows excellent stability after 2000 cycle experiments.The Ag NWs/LIG flexible strain sensor shows good performance when placed on the back of the hand,around the eyes,etc.It is demonstrated that Ag NWs/LIG flexible strain sensors have good application potential in human physiological activity monitoring,health management and medical fields,and provide a low-strain,high-sensitivity sensor design strategy for flexible wearable devices.
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    High performance rotary triboelectric nanogenerator based on wool charge supplementation strategy with low wear

    CAI MingZheHAO CongCongWANG ZeKunZHAI Cong...
    3535-3545页
    查看更多>>摘要：Triboelectric nanogenerator(TENG)is an emerging method for harvesting mechanical energy.In traditional rotary TENGs(R-TENGs),the mutual friction between positive and negative friction materials significantly shortens their operational lifespan.The non-contact triboelectric nanogenerator addresses this issue effectively;however,its low output performance still limits practical applications.In this work,we introduce a novel charge supplementation strategy to enhance the performance of NCR-TENGs.This strategy involves directly affixing wool between the Cu electrodes of the NCR-TENG,while the negative friction material is modified by doping with MXene,resulting in a substantial enhancement of output.The voltage,current,and charge transfer increased by 4.5,4.5,and 4.8 times,respectively,reaching 451 V,21.2 μA and 47 nC.Furthermore,NCR-TENG demonstrates remarkable stability,maintaining 100％output characteristics after 33,600 cycles.The output power reaches 2.3 mW when load resistance is 107 Ω.It takes only 0.8 s to charge a 0.1 μF capacitor to 10 V.This work not only improves the output performance of the NCR-TENG but also retains the capability of low-speed startup while maintaining high wear resistance.The simple and effective charge supplementation strategy proposed here provides a new perspective for further improving the output characteristics of NCR-TENGs.NCR-TENG has potential application prospects in harvesting wind energy to power traffic flow sensor networks,detecting environmental and vehicle information,and optimizing traffic signal control.
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    TrinityMag:A novel magnetically actuated miniature robot manipulating system with a human-scale workspace

    LI DongCHEN BinHanHUANG ChenYangXU Sheng...
    3546-3558页
    查看更多>>摘要：The development of the magnetic manipulating system is essential for applications of magnetically actuated miniature robots in biomedical practice,such as targeted therapy and precise surgery.However,the workspaces of existing magnetic manipulating systems for miniature robots are mostly insufficient to manipulate miniature robots inside human bodies.The present study proposes an innovative electromagnets-based manipulating system,TrinityMag,which can produce dynamic three-dimensional(3D)magnetic fields in a human-scale spherical workspace with a 2.6 m diameter.The magnetic field of a single electromagnet is simulated,and a new calibration technic is designed based on deep learning networks.Then,the arrangement of three elec-tromagnets is optimized to produce maximal 3D arbitrary magnetic fields with limited currents.Moreover,a target-tracking algorithm is developed so that the TrinityMag can track the miniature robot in real time.Finally,the TrinityMag is validated in experiments to manipulate a soft millirobot to move in human-scale tortuous tracks with two types of locomotions.The maximum speed of the soft millirobot reaches 11.05 body length/s.Our work contributes to a significant increment in the workspace of the electromagnets-based manipulating system for miniature robots.We further expect that the TrinityMag could push the applications of miniature robots from laboratory to clinical practice.
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