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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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    Impacts of spatially inconsistent permafrost degradation on streamflow in the Lena River Basin

    XUE ZeHuanWANG YiChuZHAO YiLI DongDeng...
    3559-3570页
    查看更多>>摘要：Although permafrost degradation contributes significantly to hydrological change in cold regions,gaps remain in our under-standing of streamflow variation induced by degrading permafrost in different river basins.We therefore used a deep learning model to simulate the long-term(≥ 30 years)monthly streamflow at 60 hydrological stations along the Lena River,the third longest circum-Arctic river.Analyzing the effects of precipitation,temperature,and thaw depth on streamflow variation throughout the Lena River Basin,we identified two feedback patterns relating streamflow to warming permafrost,observed in areas of continuous and discontinuous permafrost.In northern plain regions with continuous permafrost,94％of stations presented an increasing trend in annual streamflow from the 1900s to the 2010s due to permafrost degradation.The enhanced streamflow was mainly due to increased meltwater in the flood season.In southern regions covered by both continuous and discontinuous permafrost,approximately 38％of stations exhibited a declining trend in annual streamflow in response to permafrost degradation,with a high proportion(61％)located in mountain regions(elevation ≥ 500 m).The decline is attributed to the enhanced infiltration capacity of thawing frozen layers within discontinuous permafrost regions.Our study provides new insights into the mechanisms behind permafrost degradation-induced streamflow variation and highlights the importance of formulating tailored strategies for sustainable river management in cold regions experiencing climate change.
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    Coupling effect analysis of dam break flood spread and building collapse based on numerical simulation

    SONG TianXuLIU JiaHongMEI ChaoZHANG MengXue...
    3571-3584页
    查看更多>>摘要：Large-scale floods induced by dam failures could cause significant structural damage to buildings and massive loss of life.The coupling effect of large-scale flood spread and building collapse has complex impacts on the entire flow field,affecting flood risk assessment and building vulnerability evaluation.In this paper,a dynamic elevation change model designed to seamlessly interface with a structural vulnerability assessment model to investigate the interaction effect between floods and buildings is presented.The efficiency of the framework was validated by reconstructing the Gleno Dam-Break flood in Italy.Subsequently,a hydrodynamic model of the Jinsha-Yalong River that considers dynamic building collapse was established.The proposed model was compared with two traditional building treatment approaches and one that ignored the buildings.The results show that the interaction between the flood and buildings decreases the low-velocity area(below 1 m/s)by 7.44％-9.56％while increasing the high velocity area(above 4 m/s)by 10.71％-11.96％.Traditional and neglecting building treatments provide preliminary insights into densely built areas,and the latter could be an alternative for simplification because it can represent the worst-case scenario.Building collapse in response to large-scale floods typically occurs in four stages:flood spread,rapid expansion,gradual expansion,and flood recession.This analysis offers novel perspectives on flood prediction and simulations where the floodplain may contain buildings.This method could be useful for assessing structural vulnerability associated with large building stocks and developing flood mitigation strategies in densely populated areas.
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    Adaptive multiscale wavelet-guided periodic sparse representation for bearing incipient fault feature extraction

    NIU MaoGuiJIANG HongKaiYAO RenHe
    3585-3596页
    查看更多>>摘要：Currently,accurately extracting early-stage bearing incipient fault features is urgent and challenging.This paper introduces a novel method called adaptive multiscale wavelet-guided periodic sparse representation(AMWPSR)to address this issue.For the first time,the dual-tree complex wavelet transform is applied to construct the linear transformation for the AMWPSR model.This transform offers superior shift invariance and minimizes spectrum aliasing.By integrating this linear transformation with the generalized minimax concave penalty term,a new sparse representation model is developed to recover faulty impulse components from heavily disturbed vibration signals.During each iteration of the AMWPSR process,the impulse periods of sparse signals are adaptively estimated,and the periodicity of the latest sparse signal is augmented using the final estimated period.Simulation studies demonstrate that AMWPSR can effectively estimate periodic impulses even in noisy environments,demonstrating greater accuracy and robustness in recovering faulty impulse components than existing techniques.Further validation through research on two sets of bearing life cycle data shows that AMWPSR delivers superior fault diagnosis results.
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    A new local resonance metamaterial for flat and cylindrical structures depended on elastic chiral spiral beams

    LIU JingZENG TanNI HengTaiHOU YingYing...
    3597-3611页
    查看更多>>摘要：In practical engineering structures,complex low-frequency vibrations are often encountered.However,most reported elastic metamaterials are designed for high-frequency ranges or rely on substantial additional mass to control low-frequency vibrations,making them difficult to apply in real-world engineering scenarios.To address this limitation,we propose a homogeneous locally resonance metamaterial with tunable low-frequency bandgaps.This design overcomes the challenges associated with conven-tional local resonators,which are often large and heavy,making them impractical for engineering applications.By integrating resonator structures composed of elastic chiral spiral beams and mass blocks onto the supporting structure,we achieve low-frequency vibration control within limited spaces,broadband absorption with gradient parameter units,and vibration control under different curvatures.The effectiveness of the proposed design is validated through comparative computational methods,dispersion curve calculations,frequency response simulations,and experimental tests.This study proposes a novel LRM structure with a full bandgap from 96.9 to 124 Hz.The transmittance is negative in most of the band gap range,which has been verified through numerical and experimental results.This approach effectively meets the complex low-frequency vibration control requirements of various curved structures in engineering applications,providing a viable solution for low-frequency vibration control of structures such as flat and cylindrical shells.
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    Evolution and formation mechanism of rail corrugation in high-speed railways involving the longitudinal wheel-track coupling relationship

    SHEN YiZheZHU ShengYangYANG JianJinZHAI WanMing...
    3612-3625页
    查看更多>>摘要：Rail corrugation poses a significant threat to train running safety in the field of railway engineering.Therefore,this study employs numerical analysis to investigate the evolution and formation mechanism of rail corrugation in high-speed railways(HSR).Firstly,a three-dimensional(3D)vehicle-track coupled dynamics(VTCD)model is established,which considers the longitudinal wheel-rail(WR)coupling relationship more adequately.Then,by integrating the USFD wear model into this 3D VTCD model,a long-term iterative wear model is developed to reproduce the corrugation evolution process.The predicted corrugation exhibits two distinct wavelength components and closely matches the sample obtained from China's HSR,validating the established model in terms of reliability.Furthermore,the formation mechanism of these two wavelength components is investigated by analyzing the harmonic behavior of vehicle-track coupled systems(VTCS)and the evolution law of rail corrugation under different calculation conditions.The findings reveal that the 3rd-order vertical rail local bending mode(RLBM)between two wheelsets of a bogie(TW-B)is the primary factor contributing to the formation of the long-wavelength component of rail corrugation.The discrete supports of the fasteners do not affect the 3rd-order vertical RLBM,which can be stably excited.Moreover,the vertical rail vibration has a substantial coupled effect on the longitudinal WR creep.When the 3rd-order vertical RLBM is excited,the coupled effect and the negative longitudinal WR creepage together evidently promote the formation of the short-wavelength component of rail corrugation.
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    Single-gait crawling robot:A solution for improving mobility and payload of soft locomotor via simple structure and easy control

    MA HaoHAO TianZeMA JiChaoSUN ZhenHao...
    3626-3628页
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    Upconversion electroluminescence enabled by plasmonic tunnel junctions

    XING GuanShengLIN ZhaoRanWANG XiangFuCHEN Bing...
    3629-3630页
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