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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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    Transient Monte Carlo simulation of phonon transport in silicon nanofilms with the local heat source

    LI JiaQiCAI JiuQingLI RuiLIU ZhiChun...
    2087-2098页
    查看更多>>摘要：Accurate prediction of junction temperature is crucial for the efficient thermal design of silicon nano-devices.In nano-scale semiconductor devices,significant ballistic effects occur due to the mean free path of phonons comparable to the heat source size and device scale.We employ a three-dimensional non-gray Monte Carlo simulation to investigate the transient heat conduction of silicon nanofilms with both single and multiple heat sources.The accuracy of the present method is first verified in the ballistic and diffusion limits.When a single local heat source is present,the width of the heat source has a significant impact on heat conduction in the domain.Notably,there is a substantial temperature jump at the boundary when the heat source width is 10 nm.With increasing heat source width,the boundary temperature jump weakens.Furthermore,we observe that the temperature excitation rate is independent of the heat source width,while the temperature influence range expands simultaneously with the increase in heat source width.Around 500 ps,the temperature and heat flux distribution in the domain stabilize.In the case of dual heat sources,the hot zone is broader than that of a single heat source,and the temperature of the hot spot decreases as the heat source spacing increases.However,the mean heat flux remains unaffected.Upon reaching a spacing of 200 nm between the heat sources,the peak temperature in the domain remains unchanged once a steady state is reached.These findings hold significant implications for the thermal design of silicon nano-devices with local heat sources.
      原文链接:
    • 万方数据
    • 维普

    Enhancement of Ising superconductivity in monolayer NbSe2 via surface fluorination

    WU JiZhengSHI WuJunWANG ChongDUAN WenHui...
    2099-2106页
    查看更多>>摘要：Recently discovered Ising superconductors have garnered considerable interest due to their anomalously large in-plane upper critical fields(Bc2).However,the requisite strong spin-orbital coupling in the Ising pairing mechanism generally renders these superconductors heavy-element dominant with notably low superconducting transition temperatures(Tc).Here,based on the Migdal-Eliashberg theory and the mean-field Bogoliubov-de Gennes Hamiltonian,we demonstrate a significant enhancement of Ising superconductivity in monolayer NbSe2 through surface fluorination,as evidenced by concomitant improvements in Tc and Bc2.This enhancement arises from three predominant factors.Firstly,fluorine atoms symmetrically and stably adhere to both sides of the monolayer NbSe2,thereby maintaining the out-of-plane mirror symmetry and locking carrier spins out-of-plane.Secondly,fluorination suppresses the charge density wave in monolayer NbSe2 and induces a van Hove singularity in the vicinity of the Fermi level,leading to a marked increase in the number of carriers and,consequently,strengthening the electron-phonon coupling(EPC).Lastly,the appearance of fluorine-related,low-frequency phonon modes further augments the EPC.Our findings suggest a promising avenue to elevate Tc in two-dimensional Ising superconductors without compromising their Ising pairing.
      原文链接:
    • 万方数据

    Hot deformation behavior and microstructure evolution of GH3536-TiB2 composites fabricated by powder metallurgy

    ZHOU ShiPengWANG ShuaiHUANG LuJunZHANG Rui...
    2107-2124页
    查看更多>>摘要：The hot deformation behavior and microstructure evolution of GH3536-TiB2 composites fabricated by powder metallurgy(PM)were examined in the temperature range of 950-1150℃ and strain rate range of 0.001-1 s-1.The hot compression stress-strain curves and the constitutive equation were obtained.In addition,the hot processing map was drawn,which indicated that the appropriate hot working window was 950-1050℃/0.001-0.1 s-1 and 1050-1100℃/0.001-0.01 s-1.The microstructure analysis showed that the splitting and spheroidization of M3B2 led to a decrease in size and volume fraction at 950-1100℃.At 1150℃,the eutectic microstructure of M3B2+γ was formed due to the dissolution of M3B2,which caused macroscopic cracking of the deformed sample.Additionally,the deformation temperature and the strain rate had little effect on the size and volume fraction of M3B2.Besides,discontinuous dynamic recrystallization(DDRX)and continuous dynamic recrystallization(CDRX)were found in the deformed microstructure,while the former was dominant.Within the test range of this work,the dynamic recrystallization(DRX)fraction of the deformed composites was high due to the bulging nucleation of numerous interfaces.The DRX grain size increased with increasing deformation temperature or decreasing strain rate.Texture analysis showed that the deformation texture of<101>//compression direction RD existed in the matrix when the deformation temperature was below 1100℃,and the texture type became<001>//RD at 1100℃.Additionally,it was also found that the<001>//RD texture was formed in M3B2 under the strain rates of 0.1 and 0.01 s-1.
      原文链接:
    • 万方数据

    A breathable,designable and flexible leather-heater used in wearable thermotherapy

    ZHU JingYuLIU YaDongXIE RuiJieZHAO YuHan...
    2125-2132页
    查看更多>>摘要：Flexible heaters with personal thermal management capabilities have great potential in thermal therapy applications due to their excellent flexibility,low power consumption,and portability.However,manufacturing wearable heating devices that are breathable,wear resistant and conformal for long-term use is still challenging.To address these issues,we designed a leather heater using breathable,biocompatible,and tailorable leather as the substrate through a simple in-situ polymerization poly-pyrrole strategy.This heater exhibits excellent heating and mechanical properties(reaching 64℃ at a voltage of 5 V with efficient Joule heat generation of 2286 W/m2 and uniform temperature distribution,and functioning properly after 1000 cycles of bendability tests).In addition,this heater displays better wear resistance and water vapor permeability rate(38.04 g/(m2h)).The cuttable and sewable of leather gives the strategy ability to be flexibly designed to mold the heater to the specific requirements of different body parts,providing a new approach to wearable thermal therapy.
      原文链接:
    • 万方数据

    Effects of rafting on the meso deformation and fracture behaviour of a Ni-based single crystal superalloy at room temperature:In-situ observation and simulation

    TAN LongYANG XiaoGuangSHI DuoQiFAN YongSheng...
    2133-2146页
    查看更多>>摘要：Microstructural rafting of Ni-based single-crystal(SC)superalloys is inevitable at elevated temperatures during long-term service with mechanical loading,which significantly affects the mechanical behaviour of the material.In this study,the effects of rafting on the mesodeformation and fracture behaviour of a Ni-based SC superalloy under cyclic and tensile loads were investigated using in situ scanning electron microscopy(SEM),digital image correlation(DIC),and crystal plasticity finite element method(CP-FEM)simulations.The results indicated that the tensile strength decreased significantly in the rafted specimens.In the cyclic tests,both the virgin and rafted specimens showed an increase in the maximum shear strain with cycle number.The interaction of cross-slip bands was captured by in situ SEM-DIC around the micro-notch of the virgin specimens during the tensile test,while a more homogeneous local deformation field was observed in the rafting specimens.In addition,the fracture behaviour was strongly influenced by the rafting morphology.The crack exhibited instantaneous and long-range fracture features along the octahedral plane as it propagated in the rafting specimen,whereas it deflected over a short distance between the crystallographic planes at an early stage in the virgin specimen,which is consistent with the CP-FEM results.Furthermore,the CP-FEM results for the crack initiation direction on(1(1)1)dominant slip plane were consistent with the in situ SEM observations.
      原文链接:
    • 万方数据

    Lithography-free polarization-dependent absorber based on α-MoO3

    HU YangWU XiaoHuLI HongJuZHAO Yi...
    2147-2152页
    查看更多>>摘要：As a natural biaxial hyperbolic material,α-phase molybdenum trioxide(α-MoO3)exhibits dielectric and metallic properties in the plane,rendering it an exceptional candidate for polarization-dependent devices.In this work,we design a lithography-free polarization-dependent absorber consisting of an α-MoO3 film,a germanium layer,and a silver substrate.The results show that a narrowband absorption of up to 0.99 is achieved at a wavelength of 12.2 pm for transverse magnetic polarization.In contrast,the absorption is only 0.06 at this wavelength for transverse electric polarization.This remarkable polarization-dependent absorption performance is attributed to the coupling of epsilon-near-zero modes and Fabry-Perot resonances,which is confirmed by the electric field and power dissipation density distributions.Furthermore,strong polarization-dependent performance could also be achieved when the crystal axis of α-MoO3 is rotated in the out-of-plane.This work demonstrates that in-plane anisotropic α-MoO3 has the potential for designing high polarization-dependent devices.
      原文链接:
    • 万方数据

    Synergistic injection of the thermosensitive hydrogel and Bi-based alloy bone cement for orthopaedic repair

    LIU SiCongLI LeiJIANG ChanYuanWANG QianYu...
    2153-2163页
    查看更多>>摘要：Low-melting-point alloys have the advantages of good biocompatibility,plasticity,and near-bone mechanical strength,making them suitable as bone defect-filling materials for direct injection into defective bone sites.However,using low-melting-point alloys for orthopedic implants poses the challenge of causing thermal damage to the surrounding bone tissue during injection.In this study,a thermosensitive hydrogel is prepared and synergistically injected into the bone defect site with BiInSn.BiInSn solidifies and releases heat during injection,while the thermosensitive hydrogel absorbs heat and transforms into a gel state,encapsulating BiInSn.Therefore,the surrounding bone tissue is effectively protected from thermal damage.When BiInSn and the thermosensitive hydrogel were injected synergistically,in vitro thermal experiments revealed that the maximum temperature of the surrounding bone tissue reached 42℃.This temperature is below the 47℃ threshold,which causes permanent damage to bone tissues.In vivo experiments demonstrated that rats in the BiInSn-thermosensitive hydrogel group exhibited better recovery at the bone defect sites.These results suggest that the synergistic injection of Bi-based alloy and thermosensitive hydrogel is beneficial in reducing thermal damage to bone tissue,guiding bone tissue growth,and effectively facilitating the repair of bone defects.
      原文链接:
    • 万方数据
    • 维普

    Solar-powered miniature robot for on-site oil spill treatment under magnetic steering

    WANG BenCHEN YunRuiWANG YunJI FengTong...
    2164-2175页
    查看更多>>摘要：Walking on the water surface is an effective method for miniature robots to transport payloads with dramatically decreased interfacial drag.Current aquatic robots reported are generally actuated by a beam of focused light that can trigger asymmetrical deformation,enabling the directional movement through horizontal momentum transfer of photoinduced actuation force to the water.However,the operations are heavily dependent on manual manipulation of the focused light,making the long-term actuation and application of the aquatic robots in vast scenarios challenging.Herein,we developed a kind of water strider-inspired robot that can autonomously manage the motion on the water surface under solar irradiation,with their direction steerable by a magnetic field.The motion of this bioinspired robot on the water surface was achieved by the use of a solar cell panel as a driving module to enable propulsive motion based on the conversion of light-electric-mechanical energies.The superhydrophobic design of its leg surfaces enables the aquatic robots with weight-bearing and drag-reducing abilities.With the assistance of magnetic navigation,the bioinspired robot can continuously and controllably locomote to the oily spill floating on the water body and collect them with high efficiency.For further demonstration,the treatment of oil spills in a campus pool with high efficiency has also been achieved.This on-site oil-spill treating strategy,taking advantage of a home-made bioinspired robot actuated by natural sunlight under magnetic steering,shows great potential applications in water-body remediation.
      原文链接:
    • 万方数据
    • 维普

    Image attention transformer network for indoor 3D object detection

    REN KeYanYAN TongHU ZhaoXinHAN HongGui...
    2176-2190页
    查看更多>>摘要：Point clouds and RGB images are both critical data for 3D object detection.While recent multi-modal methods combine them directly and show remarkable performances,they ignore the distinct forms of these two types of data.For mitigating the influence of this intrinsic difference on performance,we propose a novel but effective fusion model named LI-Attention model,which takes both RGB features and point cloud features into consideration and assigns a weight to each RGB feature by attention mechanism.Furthermore,based on the LI-Attention model,we propose a 3D object detection method called image attention transformer network(IAT-Net)specialized for indoor RGB-D scene.Compared with previous work on multi-modal detection,IAT-Net fuses elaborate RGB features from 2D detection results with point cloud features in attention mechanism,meanwhile generates and refines 3D detection results with transformer model.Extensive experiments demonstrate that our approach outperforms state-of-the-art performance on two widely used benchmarks of indoor 3D object detection,SUN RGB-D and NYU Depth V2,while ablation studies have been provided to analyze the effect of each module.And the source code for the proposed IAT-Net is publicly available at https://github.com/wisper181/IAT-Net.
      原文链接:
    • 万方数据
    • 维普

    Distributed swarm control for multi-robot systems inspired by shepherding behaviors

    SUN GuiBinGU HaiBoLü JinHu
    2191-2202页
    查看更多>>摘要：Swarming behaviors play an eminent role in both biological and engineering research,and show great potential applications in many emerging fields.Traditional swarming models still lack integrity,uniformity,and stability in swarm forming processes,resulting in fragmentation and void phenomena.Inspired by the shepherding behaviors observed in nature,we propose an inte-grated negotiation-control scheme for distributed swarm control of massive robots.The core idea of this scheme is that the robots at the boundary of the group herd the internal robots to form an equilibrium swarm.For this purpose,we introduce a concept of virtual group center towards which boundary robots herd intemal robots.Then,a distributed negotiation mechanism is designed to allow each robot to negotiate the virtual group center only through local interactions with its neighbors.After that,we propose a shepherding-inspired swarm control law to drive a group of robots to form an integrated,uniform,and stable configuration from any initial states.Both numerical and flight simulations are presented to verify the effectiveness of our proposed swarm control scheme.
      原文链接:
    • 万方数据
    • 维普