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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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    Sparse identification-assisted exploration of the atomic-scale deformation mechanism in multiphase CoCrFeNi high-entropy alloys

    XIAO LuGUO XiaoXiangSUN YuTongWANG Gang...
    1124-1132页
    查看更多>>摘要：This study investigated the atomic-scale deformation mechanism of multiphase CoCrFeNi high-entropy alloys(HEAs)at liquid helium,liquid nitrogen,and room temperatures.A million-atom multiphase HEA was prepared using molecular dynamics simulation involving melt and quench processes.The HEA exhibited high-density dislocations and some twins,consistent with experimental observations.Quantitative analysis revealed an inconsistent evolution of the microstructure under tensile de-formation.In particular,the elastic and initial plastic stages exhibited an increase in the disordered structure at the expense of the face-centered cubic and hexagonal close-packed structures,followed by a subsequent transformation involving multiple structural rearrangements.Furthermore,through sparse identification,a model depicting microstructural evolution during ten-sion was extracted for the CoCrFeNi HEA at three typical temperatures and three tensile rates.The model highlighted the importance of the body-centered cubic structure in the evolutionary process.
      原文链接:
    • 万方数据
    • 维普

    Dual-band dynamic reconfigurable intelligent surface for signal enhancement in millimeter wave

    YAO HuiMingDU XinRunWANG HengBinGAO Song...
    1133-1138页
    查看更多>>摘要：Millimeter wave with large bandwidth,high transmission rate,and low delay is considered a reliable altemative to cope with the spectrum shortage.However,the fast attenuation and narrow beam characteristics make it difficult to achieve long-distance or wide-range applications.Here,a 1-bit dual-band reflective reconfigurable intelligent surface(RIS)for signal enhancement in millimeter wave with 16x16 elements is designed,fabricated,and measured.Different from most existent RIS,dynamic programming is realized at two separate frequency bands by integrating the PIN diodes and field-programmable gate array(FPGA).Particularly,the beam deflection,dual-beam,and multi-beam are created based on the coding theory and convolution operation,proving the effectiveness of wavefront manipulation.Moreover,the far-field pattems and signal power with different coding sequences are measured and compared.It is indicated that the received signal power is 6-7 dB stronger than that without coding,which shows good agreement with the desired expectations.The proposed reconfigurable metasurface exhibits great potential in beam forming,making it a promising candidate for progressive wireless communication applications.
      原文链接:
    • 万方数据
    • 维普

    Phase-field simulation of precipitation kinetics and creep properties of Ni-Al-Cr/Ta superalloys

    YANG ShuaiGeZHANG ZanZHUO JiChengLONG HongLi...
    1139-1150页
    查看更多>>摘要：The precipitation kinetics of γ'-Ni3(Al,Ta)phase and creep properties of Ni-15Al-xTa at.％superalloys are investigated by the crystal plasticity phase-field simulation.The results show that the high Ta content brings a lower creep strain for the deceleration and steady creep stage,while the creep lifetime is shorter.The large external strain intensifies the creep damage and shortens the creep life of Ni-15Al-3Ta at.％superalloy.The kinetics evolution and elements distribution are revealed in the quaternary Ni-10Al-8.5Cr-xTa(x=1.5 at.％,2.0 at.％,2.5 at.％)superalloys by the multi-component phase-field simulation.The anti-phase boundary(APB)changes the coarsening mechanism of γ'phase,and Ta promotes the precipitation of γ'phase with an increasing volume fraction and particle number.The composition difference between γ'and γ phases increases with the rising of Ta content,the strong partitioning of Ta to γ'phase strengthens the partitioning of Ni and Cr to γ matrix,and Ta shows a superiority than Al in the lattice site occupation of L12-Ni3(Al,X)phases.As an important γ'phase forming element,the optimization of Ta content is essential for improving the mechanical properties of Ni-based superalloys.
      原文链接:
    • 万方数据
    • 维普

    A multiple flame-retardant,early fire-warning,and highly sensitive thread-shaped all-fabric-based piezoresistive sensor

    LI WeiBiaoZHANG ShuaiMA ShuQiWANG JiaCheng...
    1151-1159页
    查看更多>>摘要：In the artificial intelligence age,multifunctional and intelligent fireproof fabric-based electronics are urgently needed.Herein,a novel thread-shaped all-fabric-based piezoresistive sensor(denoted as TAFPS)with properties such as flame retardancy,fire-warning,and piezoresistivity is proposed,which is composed of an inner nickel-plated fabric electrode,a multifunctional double helix fabric,and an external flame-retardant encapsulation fabric.Owing to the multiple flame-retardant properties of glass fiber tubular fabric,aminated carbon nanotubes(ACNTs),and ammonium polyphosphate,the char residue of the TAFPS reaches 40.3 wt％at 800℃.In addition,the heat-sensitive effect of ACNTs during combustion causes a rapid decrease in the TAFPS resistance,triggering the fire alarm system within 2 s.Additionally,benefiting from the force-sensitive behavior of the double helix layer and tightly wrapped pattern of the external heat-shrinkable tubular fabric,TAFPS demonstrated a high sensitivity of 4.40 kPa 1(0-5.81 kPa)and good stability for 10000 s.Considering its excellent flame resistance,high sensitivity,and agreeable stability,the developed TAFPS can be integrated into fire suits to monitor the exercise training process and the external fire environment.This work offers a novel approach for fabricating all-fabric-based piezoresistive sensors in the future for fire prevention and fire alarms,with promising applications in fire protection,the Internet of Things,and smart apparel.
      原文链接:
    • 万方数据
    • 维普

    Melittin enhanced intracellular trehalose with synergistic membrane stabilization of macromolecular protectants for cell cryopreservation

    NIU QingJingGAO ShuHuiZHU KongYingREN LiXia...
    1160-1169页
    查看更多>>摘要：Cryopreservation plays an essential role in biobanking and cell therapy,but the physiological toxicity of traditional cryopro-tectants such as glycerol and dimethyl sulfoxide(DMSO)has raised safety issues for biomedical applications.Trehalose,a nonreducing disaccharide that accumulates in desiccation-or cold-tolerant organisms,has been considered as a biocompatible cryoprotectant.Herein,a naturally occurring membrane-active cationic peptide,melittin,was utilized to facilitate membrane-impermeable trehalose entry into cells for effective cell cryopreservation.Poly(ethylene glycol)and poly(vinyl pyrrolidone)were applied as macromolecular protectants to improve the stabilization of cell membranes.Upon the optimal protocol,the post-thaw recovery of human red blood cells in freezing bags at a hematocrit of～50％could achieve 82.9％with favorable cell morphologies and physiological functions.Furthermore,the cryosurvival of L929 fibroblasts reached 84.3％compared to the conventional method using 10％(v/v)DMSO.In short,this work by using trehalose and melittin provides a biocompatible solvent-free approach for long-term cryostorage of cells.
      原文链接:
    • 万方数据
    • 维普

    3D printed β-sheet-reinforced natural polymer hydrogel bilayer tissue engineering scaffold

    ZHAO XinRuiNIE XiongFengZHANG XiaoPingSUN YaGe...
    1170-1184页
    查看更多>>摘要：It remains a significant challenge to fabricate natural polymer(NP)hydrogels with anti-swelling ability and high strengths in the physiological environment.Herein,the β-sheet-reinforced NP hydrogel is developed by copolymerizing methacrylated gelatin(GelMA)and methacrylated silk fibroin(SFMA)in aqueous solution,followed by ethanol treatment(named GelMA-SFMA-AL).The β-sheets formed by SFMA can act as a stable physical crosslink to enhance the mechanical properties and prolong the degradation of the GelMA network.Importantly,the chemical crosslinking in the GelMA-SFMA hydrogel prevents excessive aggregation of hydrophobic β-sheets,thereby avoiding the formation of brittle hydrogel.The obtained GelMA-SFMA-AL hydrogels exhibit considerably enhanced mechanical properties(Young's modulus:0.89-3.68 MPa;tensile strength:0.31-0.96 MPa;toughness:0.09-0.63 MJ/m3;compressive modulus:0.78-2.20 MPa;compressive strength:2.65-5.93 MPa)compared with GelMA-SFMA hydrogels(Young's modulus:0.04-0.13 MPa;tensile strength:0.04-0.07 MPa;toughness:0.01-0.02 MJ/m3;compressive modulus:0.03-0.09 MPa;compressive strength:0.30-0.64 MPa).A bilayer osteochondral scaffold is constructed via digital light processing(DLP)three-dimensiaonl(3D)printing technology,comprising GelMA-SFMA@di-clofenac sodium(DS)-AL as the top layer and GelMA-SFMA@bioactive glass(BG)-AL as the bottom layer.The bilayer hydrogel scaffold is demonstrated to support cell attachment and spreading,and facilitate osteogenic differentiation of rat bone marrow stem cells in vitro.In vivo implantation experiment suggests this bilayer scaffold is promising to be used for osteo-chondral tissue regeneration.
      原文链接:
    • 万方数据

    A compact bimorph rotary piezoelectric actuator with customized small power supply

    DENG JieLIU DaQingWANG WeiYiLIU YingXiang...
    1185-1195页
    查看更多>>摘要：Inertial piezoelectric actuators are widely applied in precision devices with simple structure and accurate movement.However,existing inertial piezoelectric actuators still face the challenges of rollback motion and bulky power supply.In this work,an alternate excitation strategy and a customized small power supply for a bimorph rotary piezoelectric actuator(BRPA)are proposed to solve the problems.The BRPA prototype is designed with a bipedal symmetrical structure,measuring 35 mm in height and 32 mm in diameter,which has a maximum rotation velocity of 0.247 rad/s and a resolution of 0.66 μrad.Thanks to the bipedal symmetrical structure,the friction directions between the driving feet and the rotor can be coordinated to suppress the rollback.The rollback ratio is almost zero when the phase difference of the exciting signal is set as 180°.The customized power supply is designed and manufactured,whose size is 58 mm×56 mm×46 mm.It can output signals for the single step mode and the continuous mode,and they are adopted to excite BRPA to achieve a small stroke with one single step and a large stroke with continuous step,respectively.Then,an experimental system for optical fiber alignment is developed based on the BRPA and the customized small power supply,the experiment has verified the practicability of this work in the precision fields,especially in the miniaturized precision systems.
      原文链接:
    • 万方数据
    • 维普

    Cable-driven legged landing gear for unmanned helicopter:Prototype design,optimization and performance assessment

    TIAN BaoLinGAO HaiBoYU HaiTaoSHAN HaoMin...
    1196-1214页
    查看更多>>摘要：Unmanned helicopters equipped with adaptive landing gear will dramatically extend their application especially in dealing with challenging terrains.This study presents a novel cable-driven legged landing gear(CLG)with differential transmission for unmanned helicopters in complex landing environments.To obtain the preferred configuration of the legged mechanism,a multi-objective optimization framework for the CLG is constructed by concurrently considering terrain adaptability,landing stability and reasonable linkage of intemal forces.The non-dominated sorting genetic algorithm Ⅱ is employed to numerically acquire the optimal scale parameters that guide the mechanical design of the CLG.An unmanned helicopter prototype equipped with the devised CLG is developed with key performance assessment.Experimental results show that the devised CLG can provide energy-efficient support over uneven terrains(totally driven torque demand less than 0.l N m)in quasi-static landing tests,and favorable terrain adaptability(posture fluctuation of the fuselage less than±1°)in unknown slope landing tests.These exhibited merits give the proposed CLG the potential to enhance the landing performance of future aircraft in extreme en-vironments.
      原文链接:
    • 万方数据
    • 维普

    WeldNet:A voxel-based deep learning network for point cloud annular weld seam detection

    WANG HuiRONG YouMinXU JiaJunXIANG SongMing...
    1215-1225页
    查看更多>>摘要：Weld seam detection is an important part of automated welding.At present,few studies have been conducted on annular weld seams,and a lot of defects exist in the point cloud model of the tube sheet obtained by RGB-D cameras and photography methods.Aiming at the above problems,this paper proposed an annular weld seam detection network named WeldNet where a voxel feature encoding layer was adaptively improved for annular weld seams,the sparse convolutional network and region proposal network(RPN)were used to detect annular weld seam position,and an annular weld seam detection loss function was designed.Further,an annular weld seam dataset was established to train the network.Compared with the random sampling consistency(RANSAC)method,WeldNet has a higher detection accuracy,as well as a higher detection success rate which has increased by 23％.Compared with U-Net,WeldNet has been proven to achieve a better detection result,and the intersection over the union of the weld seam detection is improved by 17.8％.
      原文链接:
    • 万方数据
    • 维普

    Partition and planning:A human-like motion decision for UAV in trap environment

    CHEN JinTaoZHOU QiREN HongRuLI HongYi...
    1226-1237页
    查看更多>>摘要：This paper presents a human-like motion decision-making method for unmanned aerial vehicles(UAVs)navigating in trap envi-ronments.We proposed a space partitioning method based on sampling and consistency control to conduct a preliminary analysis of the indoor environment based on architectural blueprints.This method reduces the dimensionality of the path planning problem,thereby enhancing the efficiency.Then,we designed a target-switching logic for the dynamic window approach.This improve-ment endows the UAV with the capability of both real-time obstacle avoidance and global navigation,enhancing the efficiency of the UAV in flying to task spots indoors.Additionally,by applying human-like methods of batch distance perception and obstacle perception to this scheme,we have further enhanced the robustness and efficiency of path decisions.Finally,considering the scenario of high-rise fire rescue,we conducted simulation verification.It demonstrates that our scheme enhances the efficiency and robustness of path planning.
      原文链接:
    • 万方数据
    • 维普