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Self-initiated static-dynamic state transition behavior and triggering mechanism of strain rockburst using three-dimensional discrete element method

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underground Space 2024年第3期16卷 143-163页

作者： Yuan Qian cheng Zhao rui Wei rui Zhang Lin Huang Huiguan chen Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical and underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China School of Engineering Tibet UniversityLhasaTibet850000China

The accurate understanding of rockburst mechanism poses a global challenge in the field of rock *** for strain rockburst,achieving self-initiated static-dynamic state transition is a crucial step in the formation of catastrophic ***,the state transition behavior and its impact on rockburst have not received sufficient attention,and are still poorly ***,this study specifically focuses on the state transition behavior,aiming to investigate its abrupt transition process and formation mechanism,and triggering effects on *** facilitate the study,a novel burst rock-surrounding rock combined laboratory test model is proposed and its effectiveness is validated through experiment ***,corresponding numerical models are established using the three-dimensional(3D)discrete element method(DEM),enabling successful simulation of static brittle failure and rockbursts of varying intensities under quasi-static displacement loading ***,through secondary development,comprehensive recording of the mechanical and energy information pertaining to the combined specimen system and its subsystems is *** a result of numerical investigation studies,the elastic rebound dynamic behavior of the surrounding rock was discovered and identified as the key factor triggering rockburst and controlling its *** impact loading on the burst rock,induced by elastic rebound,directly initiates the dynamic processes of rockburst,serving as the direct ***,the transient work and energy convergence towards the burst rock resulting from elastic rebound are recognized as the inherent cause of ***,it has been observed that a larger extent of surrounding rock leads to a stronger elastic rebound,thereby directly contributing to a more intense *** findings can provide novel theoretical insights for the exploring of rockburst mechanism and the development of monitoring and

关键词： Strain rockburst Static-dynamic state transition Self-initiation Triggering mechanism Elastic rebound Discrete element method

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Reconfigurable mechanism-based metamaterials for ternary-coded elastic wave polarizers and programmable refraction control

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1225-1242页

作者： Zhou Hu Zhibo WEI Yan chen rui ZHu School of Aerospace Engineering Beijing Institute of TechnologyBeijing100081China School of Mechanical Engineering Tianjin UniversityTianjin300350China Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin UniversityTianjin300350China

Elastic metamaterials with unusual elastic properties offer unprecedented ways to modulate the polarization and propagation of elastic ***,most of them rely on the resonant structural components,and thus are frequency-dependent and ***,we present a reconfigurable 2D mechanism-based metamaterial which possesses transformable and frequency-independent elastic *** on the proposed mechanism-based metamaterial,interesting functionalities,such as ternarycoded elastic wave polarizer and programmable refraction,are ***,unique ternary-coded polarizers,with 1-trit polarization filtering and 2-trit polarization separating of longitudinal and transverse waves,are first ***,the strong anisotropy of the proposed metamaterial is harnessed to realize positive-negative bi-refraction,only-positive refraction,and only-negative ***,the wave functions with detailed microstructures are numerically verified.

关键词： elastic metamaterial elastic wave reconfigurable design zero mode ternary code programmable refraction

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Reliability modelling and assessment of CMOS image sensor under radiation environment

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Chinese j.urnal of Aeronautics 2024年第9期37卷 297-311页

作者： Zhao TAO Wenbin chen Xiaoyang LI rui KANG School of Reliability and Systems Enginering Beihang UniversityBejing 00191China Science and Technologyon Reliabiliy and Environmental Engineering Laboratory Beijing 100191China

The Complementary Metal-Oxide Semiconductor(CMOS)image sensor is a critical component with the function of providing accurate positioning in many space application *** long-time operation in space environments,there are radiation related degradation and var-ious uncertainties affecting the positioning accuracy of CMOS image sensors,which further leads to a reliability reduction of CMOS image ***,the reliability of CMOS image sensors is related to their specified function,degradation,and uncertainties;however,current research has not fully described this *** this paper,a comprehensive approach to reliability modelling of CMOs image sensors is proposed based on the reliability science ***,the perfor-mance margin modelling of centroid positioning accuracy is ***,the degradation model of CMOS image sensors is derived considering the dark current increase induced by the total ionizing dose ***,various uncertainties are analyzed and quantified,and the measure-ment equation of reliability is proposed.A case study of a CMOS image sensor is conducted to apply the proposed method,and the sensitivity analysis can provide suggestions for design and use of CMOS image sensors to ensure reliability.A simulation study is conducted to present the advantages oftheproposed comprehensive approach.

关键词： Complementary metal-oxide semiconductor image sensor Degradation Reliability Reliability science principles Total ionizingdose effects uncertainty analysis

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Learning group interaction for sports video understanding from a perspective of athlete

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Frontiers of Computer Science 2024年第4期18卷 175-188页

作者： rui HE Zehua Fu Qingjie LIu Yunhong WANG Xunxun chen Intelligent Recognition and Image Processing(IRIP)Lab School of Computer Science and EngineeringBeihang UniversityBeijing 100191China Hangzhou Innovation Institute Behang UniversityHangzhou 310051China National Computer Network Emergency Response Technical Team/Coordination Center of China(CNCERT or CNCERT/CC) Beijing 100029China

Learning activities interactions between small groups is a key step in understanding team sports *** research focusing on team sports videos can be strictly regarded from the perspective of the audience rather than the *** team sports videos such as volleyball and basketball videos,there are plenty of intra-team and inter-team *** this paper,a new task named Group Scene Graph Generation is introduced to better understand intra-team relations and inter-team relations in sports *** tackle this problem,a novel Hierarchical Relation Network is *** all players in a video are finely divided into two teams,the feature of the two teams’activities and interactions will be enhanced by Graph Convolutional Networks,which are finally recognized to generate Group Scene *** evaluation,built on Volleyball dataset with additional 9660 team activity labels,a Volleyball+dataset is proposed.A baseline is set for better comparison and our experimental results demonstrate the effectiveness of our ***,the idea of our method can be directly utilized in another video-based task,Group Activity *** show the priority of our method and display the link between the two ***,from the athlete’s view,we elaborately present an interpretation that shows how to utilize Group Scene Graph to analyze teams’activities and provide professional gaming suggestions.

关键词： group scene graph group activity recognition scene graph generation graph convolutional network sports video understanding

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Cobalt-loaded carbon nanotubes boosted aerobic ciprofloxacin transformation driven by sulfide:A comprehensive mechanism investigation

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Chinese Chemical Letters 2024年第3期35卷 127-134页

作者： Han-Qing Zhao Peili Lu Fei chen chen-Xuan Li rui Yan Yang Mu State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400044China CAS Key Laboratory of urban Pollutant Conversion Department of Environmental Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment College of Environment and EcologyChongqing UniversityChongqing 400045China College of Resources and Environmental Engineering Hefei University of TechnologyHefei 230009China

Sulfide oxidation under aerobic conditions can produce active oxygen for the transformation of organic pollutants in aquatic ***,the catalytic performance of transition metal-supported carbon material on this process is poor *** study found that Co-loaded carbon nanotubes(CNTs)was able to realize the efficient aerobic transformation of antibiotic ciprofloxacin(CIP)by sulfide,with the pseudo-first order reaction rate constant improved from 0.013 h^(-1)without catalyst to 0.44–0.71 h^(-1)with 100 mg/L Co-loaded *** oxygen(^(1)O_(2))was the main active specie playing key roles in the process of CIP aerobic transformation with presence of Co-loaded *** studies indicated that the excellent electron transfer ability of Co-loaded CNTs might play an important role to promote the electron transfer and facilitate the formation of intermediate H_(2)O_(2)and^(1)O_(2).Additionally,the Co-loaded CNTs/sulfide system effectively reduced the acute toxicity of organic pollutant,and Co-loaded CNTs showed remarkable cycling stability and negligible *** study gives a better understanding for the Co-loaded CNTs mediated aerobic antibiotics transformation by sulfide,and provide a reference for the application of Co-loaded carbon materials on organics aerobic transformation by sulfide.

关键词： Ciprofloxacin Aerobic transformation Co-loaded carbon nanotubes Sulfide Singlet oxygen

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Real-time arrival picking of rock microfracture signals based on convolutional-recurrent neural network and its engineering application

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j.urnal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 761-777页

作者： Bing-rui chen Xu Wang Xinhao Zhu Qing Wang Houlin Xie State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China university of Chinese Academy of Sciences Beijing100049China

Accurately picking P-and S-wave arrivals of microseismic(MS)signals in real-time directly influences the early warning of rock mass failure.A common contradiction between accuracy and computation exists in the current arrival picking ***,a real-time arrival picking method of MS signals is constructed based on a convolutional-recurrent neural network(CRNN).This method fully utilizes the advantages of convolutional layers and gated recurrent units(GRu)in extracting short-and long-term features,in order to create a precise and lightweight arrival picking ***,the synthetic signals with field noises are used to evaluate the hyperparameters of the CRNN model and obtain an optimal CRNN *** actual operation on various devices indicates that compared with the u-Net method,the CRNN method achieves faster arrival picking with less performance *** application of large underground caverns in the Yebatan hydropower station(YBT)project shows that compared with the short-term average/long-term average(STA/LTA),Akaike information criterion(AIC)and u-Net methods,the CRNN method has the highest accuracy within four sampling points,which is 87.44%for P-wave and 91.29%for S-wave,*** sum of mean absolute errors(MAESuM)of the CRNN method is 4.22 sampling points,which is lower than that of the other *** the four methods,the MS sources location calculated based on the CRNN method shows the best consistency with the actual failure,which occurs at the junction of the shaft and the second ***,the proposed method can pick up P-and S-arrival accurately and rapidly,providing a reference for rock failure analysis and evaluation in engineering applications.

关键词： Rock mass failure Microseismic event P-wave arrival S-wave arrival Deep learning

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Cone-beam computed tomography noise reduction method based on u-Net with convolutional block attention module in proton therapy

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Nuclear Science and Techniques 2024年第7期35卷 89-100页

作者： Xing-Yue Ruan Xiu-Fang Li Meng-Ya Guo Mei chen Ming Lv rui Li Zhi-Ling chen Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai201800China university of Chinese Academy of Sciences Beijing100049China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai201210China Department of Radiation Oncology Ruijin HospitalShanghai Jiao Tong University School of MedicineShanghai200025China Shanghai Key Laboratory of Proton therapy Shanghai201801China

Cone-beam computed tomography(CBCT) is mostly used for position verification during the treatment process. However,severe image artifacts in CBCT hinder its direct use in dose calculation and adaptive radiation therapy re-planning for proton therapy. In this study, an improved u-Net neural network named CBAM-u-Net was proposed for CBCT noise reduction in proton therapy, which is a CBCT denoised u-Net network with convolutional block attention modules. The datasets contained 20 groups of head and neck images. The CT images were registered to CBCT images as ground truth. The original CBCT denoised u-Net network, sCTu-Net, was trained for model performance comparison. The synthetic CT(SCT) images generated by CBAM-u-Net and the original sCTu-Net are called CBAM-SCT and u-Net-SCT images, respectively. The Hu accuracies of the CT, CBCT, and SCT images were compared using four metrics: mean absolute error(MAE), root mean square error(RMSE), peak signal-to-noise ratio(PSNR), and structure similarity index measure(SSIM). The mean values of the MAE, RMSE, PSNR, and SSIM of CBAM-SCT images were 23.80 Hu, 64.63 Hu, 52.27 dB, and 0.9919, respectively,which were superior to those of the u-Net-SCT images. To evaluate dosimetric accuracy, the range accuracy was compared for a single-energy proton beam. The γ-index pass rates of a 4 cm × 4 cm scanned field and simple plan were calculated to compare the effects of the noise reduction capabilities of the original u-Net and CBAM-u-Net on the dose calculation results. CBAM-u-Net reduced noise more effectively than sCTu-Net, particularly in high-density tissues. We proposed a CBAM-u-Net model for CBCT noise reduction in proton therapy. Owing to the excellent noise reduction capabilities of CBAM-u-Net, the proposed model provided relatively explicit information regarding patient tissues. Moreover, it maybe be used in dose calculation and adaptive treatment planning in the future.

关键词： Proton therapy Cone-beam CT CBAM-u-Net γ-index

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A novel polyionic liquid with lubricity and viscosity-increasing dual functionalities as the additive in aqueous lubrication system

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Friction 2024年第4期12卷 698-710页

作者： Bo Yu Kun ZOu rui WANG Qiang chen rui DONG Xiao LIu jiaying ZHANG Wenquan LV Qiangliang Yu Meirong CAI Feng ZHOu College of Science Nanjing Forestry UniversityNanjing 210037China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai Yantai 264006China Yantai Zhongke Research Institute of Advanced Materials and Green Chemical Engineering Yantai 264006China Institute of Polymer Materials Nanjing Forestry UniversityNanjing 210037China

The polyionic liquid poly-PEGMA-r-METAC(PPM)with quaternary ammonium has been synthesized and evaluated as additive in aqueous lubricating *** rheological behavior of aqueous lubricating fluids with PPM has been characterized to confirm PPM’s function as a viscosity *** tribological behavior of aqueous lubricating fluids with PPM has been investigated on SRV-V and MTM testing *** was found that PPM has excellent viscosity-increasing,lubricating,and anti-wear properties as an additive for aqueous,which can be attributed to the ability of PPM to form the protective film and boundary tribofilm generated from complex tribochemical reaction on rubbing *** obtained PPM with dual functions of anti-corrosion additives and viscosity index improver can play an important role in diverse lubrication regimes.

关键词： polyionic liquid lubricant additives viscosity modifier lubrication regime

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Corrosion Behavior of Pre-oxidized GH4169 Alloy with Solid NaCI Deposited in a Wet Oxygen Flow at 600 ℃

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Acta Metallurgica Sinica(English Letters) 2024年第7期37卷 1249-1264页

作者： Weidong Zhang Yu Cui Li Liu Wenquan Wang Wenzheng chen rui Li Fuhui Wang Shenyang National Laboratory for Materials Science Northeastern UniversityShenyang110819China Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

The corrosion behavior of the pre-oxidized GH4169 alloy was studied after 20 h of exposure under a solid NaCl deposit film in a wet O_(2) environment at 600℃ by mass-gain measurements,X-ray diffraction,scanning electron microscopy,transmission electron microscopy *** results indicate that the pre-oxidized GH4169 alloy undergoes serious corrosion in the corrosive *** preformed Cr_(2)O_(3) layer is gradually destroyed by deposit NaCl,and the inner Nb2O5 layer beneath the complete outer Cr_(2)O_(3) layer also reacts with NaCl to form NaNbO_(3).The electrochemical test results testified the existence of electrochemical reactions during this corrosion *** corrosion behavior of pre-oxidized GH4169 under a solid NaCl deposit film in a wet O_(2) environment at 600℃has been discussed in detail.

关键词： Pre-oxidation Solid NaCl Wet O2 Electrochemical corrosion

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Fatigue Crack Initiation and Propagation Dominated by Crystallographic Factors in TiB/near α-Ti Composite

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Acta Metallurgica Sinica(English Letters) 2024年第5期37卷 763-776页

作者： Fanchao Meng rui Zhang Shuai Wang Fengbo Sun Run chen Lujun Huang Lin Geng School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Waikato Centre for Advanced Materials and Manufacturing School of EngineeringUniversity of WaikatoHamilton 3240New Zealand State Key Laboratory of Advanced Welding and joining Harbin Institute of TechnologyHarbin 150001China

Discontinuously reinforced titanium matrix composites(DRTMCs)with a network structure have been extensively researched due to their superior combination of strength and ***,their fatigue performance has remained *** order to elucidate the fatigue behavior of DRTMCs,a tension-tension fatigue test was performed on a TiB/nearα-Ti composite with network *** results showed that the variability of fatigue lifetime increased as the stress level *** analysis indicated that fatigue crack initiation was associated with facet formation,while the subsequent propagation was hindered by the network structure comprising TiB whiskers and *** characterization further revealed that facets formed due to a combination of shear and normal *** reduction in fatigue lifetime was attributed to an increase in the effective slip length,which was influenced by the orientation of grains near the crack-initiation sites toward basal slip in the life-limiting *** in situ observation suggested that the crack initiation was facilitated by both basal and prismatic slip ofα-Ti as well as fracture of *** propagation was found to be associated with basal and prismatic slip systems with high Schmid factors,regardless of whether the crack was intergranular or intragranular.

关键词： Titanium matrix composite TiBw Fatigue lifetime variability Crack initiation Crack propagation

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