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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

月刊

1674-7321

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010-64019820

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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 features of graphitization and nitrogen-vacancy color centers in a diamond fabricated by localization femtosecond laser direct writing

    CUI LinYIN SiYuHU ZiFanWANG Lei...
    2530-2536页
    查看更多>>摘要：Femtosecond laser direct writing provides an efficient approach to fabricating single nitrogen vacancy(NV)color centers with a relatively high yield.Different from previously reported NV color centers with a random distribution in a bulk diamond or nanocrystals,this gives an opportunity to study the photophysical properties of single NV color centers with precise numbers and positions.However,ultrafast studies on single NV color centers prepared by localization femtosecond laser direct writing are still rare,especially for the graphitization inside a diamond and its relationship with single NV color centers.Here,we report the broadband transient absorption(TA)spectroscopic features of the graphitization and NV color centers in a diamond fabricated by localization femtosecond laser direct writing at room temperature under 400 nm excitation.In comparison with the graphene oxide film,the bleaching features of the graphitization point array in a diamond are similar to reduced graphene oxide,accompanied by excited state absorption signals from local carbon atom vacancy defects in graphene-like structures induced by laser writing.On the other hand,transient features of laser processing array containing single NV color centers with a yield of～50％are different from those of the graphitization point array.Our findings suggest that for ultrashort pulse processing of diamonds,broadband TA spectral signals are sensitive to the surrounding atomic environment of processing sites,which could be applied to laser writing point defects in other materials used as solid-state single photon sources.
      原文链接:
    • 万方数据
    • 维普

    Current-carrying tribological behavior of C/Cu contact pairs in extreme temperature and humidity environments for railway catenary systems

    SHEN MingXueJI DeHuiHU QiangXIAO Li...
    2537-2548页
    查看更多>>摘要：Many current-carrying contact pairs,such as those found in pantograph-catenary systems,operate in open environments and are susceptible to significant external interference from temperature and humidity variations.This study investigated the evolution of the friction coefficient and contact resistance of C/Cu contact pairs under alternating temperature,humidity,and current conditions.Through experimentation,the wear rate and microtopography of the worn surface were analyzed under various constant parameters.Subsequently,the differences in tribological behavior and current-carrying characteristics of the contact pairs under these three parameters were explored.The results revealed that the decrease in temperature resulted in a significant increase in the friction coefficient of the contact pairs,carbon wear,and copper surface roughness.Additionally,the surface oxidation rate was lower at lower temperatures.Moreover,contact resistance did not consistently increase with decreasing temperature,owing to the combined action of the contact area and the oxide film.Compared with temperature,humidity fluctuations at room temperature exerted less influence on the friction coefficient and contact resistance of the contact pairs.Dry environments rendered carbon materials vulnerable to oxidation and cracking,while excessive humidity fostered abrasive wear and arcing.High-current conditions generally degraded the tribological properties of C/Cu contacts.In the absence of current,the friction coefficient was extremely high,and the copper transfer was high.Under excessive current,copper was susceptible to plowing by carbon micro-bumps and abrasive particles,resulting in a decrease in the friction coefficient.The release of lipids from the carbon surface due to temperature elevation weakened the electrical contact performance and increased the occurrence of arc erosion,thereby exacerbating carbon wear.
      原文链接:
    • 万方数据
    • 维普

    Spectrum analysis of interval process model and its application in uncertain vibration analysis

    LI JinWuJIANG ChaoNI BingYu
    2549-2564页
    查看更多>>摘要：In recent years,the authors have extended the traditional interval method into the time dimension to develop a new mathematical tool called the"interval process model"for quantifying time-varying or dynamic uncertainties.This model employs upper and lower bounds instead of precise probability distributions to quantify uncertainty in a parameter at any given time point.It is anticipated to complement the conventional stochastic process model in the coming years owing to its relatively low dependence on experimental samples and ease of understanding for engineers.Building on our previous work,this paper proposes a spectrum analysis method to describe the frequency domain characteristics of an interval process,further strengthening the theoretical foundation of the interval process model and enhancing its applicability for complex engineering problems.In this approach,we first define the zero midpoint function interval process and its auto/cross-power spectral density(PSD)functions.We also deduce the relationship between the auto-PSD function and the auto-covariance function of the stationary zero midpoint function interval process.Next,the auto/cross-PSD function matrices of a general interval process are defined,followed by the in-troduction of the concepts of PSD function matrix and cross-PSD function matrix for interval process vectors.The spectrum analysis method is then applied to random vibration problems,leading to the creation of a spectrum-analysis-based interval vibration analysis method that determines the PSD function for the system displacement response under stationary interval process excitations.Finally,the effectiveness of the formulated spectrum-analysis-based interval vibration analysis approach is verified through two numerical examples.
      原文链接:
    • 万方数据
    • 维普

    Friction moment calculation method for tapered roller bearings under combined loads

    LI XinBinLIU JingHUANG SuHePAN Guang...
    2565-2578页
    查看更多>>摘要：Tapered roller bearings(TRBs)can withstand axial loads,radial loads,and overturning moments.The performance,safety,and efficiency of rotating machinery are directly influenced by the friction moments within the TRBs.However,most current research has relied on empirical formulas that focus on axial loads.Additionally,the friction coefficient between the rollers and the inner ring rib has been defined using simple empirical methods.In actual applications,the loads on TRBs are not purely axial or radial,and simple empirical friction coefficients do not adequately account for the varying lubrication conditions.To address this challenge,this study proposes an improved method for calculating the friction moments of TRB under combined axial and radial loads.This study employs a calculation method for sliding friction coefficients that can model dry,boundary,elastohy-drodynamic,and mixed lubrication conditions.To demonstrate the advantages of the proposed method,the friction moments obtained using the existing and proposed methods are compared.Additionally,the influence of TRB structural parameters on the friction moment is discussed.An experimental study is conducted to validate the effectiveness of the proposed method.The findings provide valuable insights for designing TRB structural parameters to minimize friction moments.
      原文链接:
    • 万方数据
    • 维普

    Combining permissioned blockchain and Bayesian best-worst method for transparent supplier selection in supply chain management

    LIU JiaJunZHANG JieLENG JieWu
    2579-2593页
    查看更多>>摘要：Supplier selection is an important business activity in order to realize the purchasing function in supply chain management.The supplier selection process includes four stages,i.e.,bidding inviting,bidding,group decision-making,and results disclosure,involving the participation of manufacturing service demanders(MSDs),manufacturing service suppliers(MSSs),and decision-makers.Nowadays,all the participants have raised concerns about the increased transparency in supplier selection.Therefore,this study proposes a transparent supplier selection method by considering the engagement of suppliers.In this method,the Bayesian best-worst method(Bayesian BWM)is used to aggregate decision-makers'preferences into the overall optimal weights of the alternative MSSs,and the MSS with the largest weight is considered the suitable MSS for MSDs.Furthermore,blockchain is introduced to record the decision-making process information about supplier selection through a customized smart contract,where MSSs act as supervisors to supervise the decision-making process through the distributed consensus mechanism rather than directly participate in the decision-making process.Finally,a case study of supplier selection in purchasing vibration acceleration sensors is presented.The result shows that the proposed method can support MSDs in selecting suitable MSS from alternative MSSs by aggregating decision-makers'preferences,and blockchain can provide credible information about the supplier selection process for MSSs,MSDs,and decision-makers.In this way,the transparency of supplier selection is enhanced.
      原文链接:
    • 万方数据
    • 维普

    A residual denoising and multiscale attention-based weighted domain adaptation network for tunnel boring machine main bearing fault diagnosis

    ZHONG TaoQIN ChengJinSHI GangZHANG ZhiNan...
    2594-2618页
    查看更多>>摘要：As a critical component of a tunnel boring machine(TBM),the precise condition monitoring and fault analysis of the main bearing is essential to guarantee the safety and efficiency of the TBM cutter drive.Currently,under conditions of strong noise and complex working environments,traditional signal decomposition and machine learning methods struggle to extract weak fault features and achieve high fault classification accuracy.To address these issues,we propose a novel residual denoising and multiscale attention-based weighted domain adaptation network(RDMA-WDAN)for TBM main bearing fault diagnosis.Our approach skillfully designs a deep feature extractor incorporating residual denoising and multiscale attention modules,achieving better domain adaptation despite significant domain interference.The residual denoising component utilizes a convolutional block to extract noise features,removing them via residual connections.Meanwhile,the multiscale attention module uses a 4-branch convolution and 3 pooling strategy-based channel-spatial attention mechanism to extract multiscale features,con-centrating on deep fault features.During training,a weighting mechanism is introduced to prioritize domain samples with clear fault features.This optimizes the deep feature extractor to obtain common features,enhancing domain adaptation.A low-speed and heavy-loaded bearing testbed was built,and fault data sets were established to validate the proposed method.Comparative experiments show that in noise domain adaptation tasks,proposed the RDMA-WDAN significantly improves target domain classification accuracy by 42.544％,23.088％,43.133％,16.344％,5.022％,and 9.233％over dense connection network(DenseNet),squeeze-excitation residual network(SE-ResNet),antinoise multiscale convolutional neural network(ANMSCNN),multiscale attention module-based convolutional neural network(MSAMCNN),domain adaptation network,and hybrid weighted domain adaptation(HWDA).In combined noise and working condition domain adaptation tasks,the RDMA-WDAN improves the accuracy by 45.672％,23.188％,43.266％,16.077％,5.716％,and 9.678％compared with baseline models.
      原文链接:
    • 万方数据
    • 维普