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Scale-space effect and scale hybridization in image intelligent recognition of geological discontinuities on rock slopes

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Journal of Rock Mechanics and Geotechnical engineering 2024年第4期16卷 1315-1336页

作者： Mingyang Wang Enzhi Wang Xiaoli Liu Congcong Wang State Key Laboratory of Hydro-science and Engineering Tsinghua UniversityBeijing100084China

Geological discontinuity(GD)plays a pivotal role in determining the catastrophic mechanical failure of jointed rock *** and efficient acquisition of GD networks is essential for characterizing and understanding the progressive damage mechanisms of slopes based on monitoring image *** by recent advances in computer vision,deep learning(DL)models have been widely utilized for image-based fracture *** multi-scale characteristics,image resolution and annotation quality of images will cause a scale-space effect(SSE)that makes features indistinguishable from noise,directly affecting the ***,this effect has not received adequate ***,we try to address this gap by collecting slope images at various proportional scales and constructing multi-scale datasets using image processing ***,we quantify the intensity of feature signals using metrics such as peak signal-to-noise ratio(PSNR)and structural similarity(SSIM).Combining these metrics with the scale-space theory,we investigate the influence of the SSE on the differentiation of multi-scale features and the accuracy of *** is found that augmenting the image's detail capacity does not always yield benefits for vision-based recognition *** light of these observations,we propose a scale hybridization approach based on the diffusion mechanism of scale-space *** results show that scale hybridization strengthens the tolerance of multi-scale feature recognition under complex environmental noise interference and significantly enhances the recognition accuracy of *** also facilitates the objective understanding,description and analysis of the rock behavior and stability of slopes from the perspective of image data.

关键词： Image processing Geological discontinuities Deep learning Multi-scale Scale-space theory Scale hybridization

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Estimating the annual runoff frequency distribution based on climatic conditions and catchment characteristics:A case study across China

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International Soil and Water Conservation Research 2023年第3期11卷 470-481页

作者： Ziwei Liu Hanbo Yang Taihua Wang Dawen Yang State Key Laboratory of Hydro-Science and Engineering Department of Hydraulic EngineeringTsinghua UniversityBeijing100084China

Estimation of the annual runoff frequency distribution is an essential basis for water resource *** study proposes a framework for estimating the annual runoff frequency distribution across252 catchments in China based on climatic conditions and catchment characteristics from 1956 to *** Budyko land-specific parameter n,which intergrates influences other than the mean climate conditions,is firstly estimated based on easily ascertainable catchment characteristics without the requirementsof having long-term runoff ***,the annual runoff statistical parameters,namely,the mean value and standard deviation(STD),are derived based on the Budyko rainfall-runoffmodel with the central moment ***,the annual runoff on any recurrence interval is obtainedby the Pearson-Ill frequency *** show that the parameter n can be estimated fromthe catchment average slope,longitude,and climatic seasonality *** estimated statistical parametersof annual runoff have acceptable agreement with observed values(mean value:R^(2)-0.94,STD:R^(2)-0.91,and both relative errors<10%).In addition,estimated annual runoff at each catchment fortypical wet and dry years(25%and 75%ranked percentiles)coincides well with observed values,with R^(2) of 0.92-0.93 and relative erors less than 10%.This result indicates the robustness of this framework forestimating the annual runoff frequency distribution,which provides a simple and effective tool forungauged orpoorlygauged catchments.

关键词： runoff distribution climatic

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Interfacial amine-assisted electrodeposition of superhydrophilic/superaerophobic metal hydroxides for robust oxygen evolution catalysis

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science China Chemistry 2025年第5期68卷 2188-2195页

作者： Qing Chen keyu Wang Shiyi Li Yixing Wang Linfeng Lei Minghui Zhu Linzhou Zhuang Zhi Xu State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and Technology Suzhou Laboratory

The oxygen evolution reaction（OER） is crucial for the electrocatalytic water electrolysis into oxygen and hydrogen,but the fourelectron transfer process hinders the OER *** realize the highly efficient water splitting,the nonprecious metal-based electrodes that can optimize the adsorption energy of intermediates and generate H2with low overpotential and robust stability are ***,we report a surface modification strategy to grow the trimetallic FeCoNi hydroxide on the amine linkersgrafted carbon cloth（CC-NH2@FeCoNi） by ***-NH2@FeCoNi possesses a superhydrophilic/superaerophobic surface,which could significantly enhance the mass transfer,and meanwhile promote the in situ generation of MOOH active ***,the superhydrophilic surface could facilitate the adsorption of abundant OH-ions,and repel the Cl-ions via electrostatic repulsive force during seawater ***,compared with the CC@FeCoNi that grown on the pure CC（320 mV）,the CC-NH2@FeCoNi needs an obviously smaller overpotential of 270 mV to achieve a current density of 100 mA cm-2,and meanwhile it exhibits a superior durability for 100 h at a current density of 200 m A cm-2in both alkaline water and *** strategy could be even applied universally in the preparation of other nonprecious metal hydroxides for efficient OER catalysis.

关键词： amine grafting superhydrophilicity superaerophobicity metal hydroxides water oxidation anticorrosion

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Loosening earth pressure above shallow trapdoor in unsaturated soil with different groundwater level

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Frontiers of Structural and Civil engineering 2024年第10期18卷 1626-1635页

作者： Yun ZHAO Zhongfang YANG Zhanglong CHEN Daosheng LING College of Civil Engineering and Architecture Henan University of TechnologyZhengzhou 450001China MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Zhejiang UniversityHangzhou 310058China State Key Laboratory of Hydro-Science and Engineering Department of Hydraulic EngineeringTsinghua UniversityBeijing 100084China

The consideration of unsaturated conditions is infrequently addressed in current Terzaghi’s soil arching research.A modified analytical method for calculation of unsaturated loosening earth pressure above shallow trapdoor is proposed in this *** assuming the existence of a vertical slip surface above the trapdoor,the stress state of the soil in the loosening area are delineated in the extended Mohr–Coulomb *** account for the non-uniform distribution of vertical stress at arbitrary points along the horizontal differential soil trip,a virtual rotation circle trajectory of major principal stress is ***,the average vertical stress acting on the soil trip is determined through integral *** into account the influence of matric suction on soil weight and apparent cohesion,the differential equation governing the soil trip is solved analytically for cases of uniform matric suction distribution and alternatively using the finite difference method for scenarios involving non-uniform matric suction *** proposed method’s validity is confirmed through comparison with published *** parameter analysis indicates that the loosening earth pressure initially decreases and subsequently increases with the increase of the soil *** the rise of groundwater level,the normalized effective loosening earth pressure shows a decreasing trend.

关键词： soil arching effect unsaturated soil trapdoor test loosening earth pressure groundwater level variation

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Evaluation of SC-CO_(2)-brine on the micro-mechanical properties of lamina shales by micro-scratch test

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Petroleum science 2024年第6期21卷 4204-4218页

作者： Liu Yang Zhao-Yang Liu Yuan-Xun Nie Zhen-Chuan Han Fei Gong Ming-Jun Li Yan Liu State Key Laboratory for Tunnel Engineering China University of Mining&Technology(Beijing)Beijing100083China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing100083China Department of Hydraulic Engineering State Key Laboratory of Hydro science and EngineeringTsinghua UniversityBeijing100084China

The mechanism of SC-CO_(2)-brine-rock interaction(SCBRI) and its effect on the mechanical properties of shale are crucial for shale oil development and CO_(2)sequestration. To clarify the influence of SCBRI on the micromechanics of shale, the lamina and matrix of shale were saturated with SC-CO_(2)-brine for 2, 4, 6,and 8 days, respectively. The micro-scratch technique was then used to measure the localized fracture toughness before and after SC-CO_(2)-brine saturation. Combining the micro-scratch results with SEM-QEMSCAN-EDS analysis, the differences in mineral composition and mechanical properties of lamina(primarily composed of carbonate minerals) and matrix(primarily composed of clay minerals) were studied. The QEMSCAN analysis and micro-scratch results indicate distinct mineralogical compositions and mechanical properties between the lamina and the matrix. The results showed that:(1) SCBRI leads to the decrease in carbonate mineral content and the significant increase in matrix porosity and laminar cracks. In addition, the damage degree increased at saturation for 6 days.(2) SCBRI weakens the mechanical properties of shale. The scratch depth of laminar and matrix increased by 34.38% and 1.02%, and the fracture toughness decreased by 34.38% and 13.11%. It showed a trend of first increasing and then decreasing.(3) SCBRI enhances the plastic deformation behavior of shale, and the plastic index of lamina and matrix increases by 18.75% and 21.58%, respectively. These results are of great significance for evaluating the mechanical properties of shale oil and gas extraction by CO_(2).

关键词： Lamina shale SC-CO_(2)-brine-rock interaction Micro-scratch test Micro-mechanical properties Elastic-plastic failure mechanism

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Flow excitation mechanisms of unbalanced impeller forces after pump power-trip of ultra-high head pump-turbines

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science China(Technological sciences) 2024年第5期67卷 1602-1611页

作者： FU XiaoLong LI DeYou LV JingWei YANG Biao WANG HongJie WEI XianZhu School of Energy Science and Engineering Harbin Institute of TechnologyHarbin150001China State Key Laboratory of Hydro-Power Equipment Harbin Institute of Large Electrical MachineryHarbin150040China

To elucidate the dynamic mechanisms of unbalanced impellers in ultra-high head pump-turbines(PTs),this study employed a one-and three-dimensional coupled method to simulate the pump power-trip(PPT)process of an ultra-high head *** investigation revealed two novel pulsation frequency components,denoted as fDVand fINFT,associated with impeller *** pulsation intensities of these components were markedly higher than those of rotor-stator interaction frequency components in ultra-high head ***,the fDVcomponents exhibited pulsations at 1–2 times the rated rotation frequency of the impeller,spanning the entire transition ***,the fINFTcomponents constituted a complex frequency band with various frequency values,primarily occurring near conditions(Q=0,n=0,M=0,and d M/dt=0).These two pulsation frequency components were predominantly linked to the unsteady evolution of dean vortices inside the volute and complex transitions of the flow pattern within the impeller,*** is crucial to note that these unbalanced flow-induced impeller axial forces can elevate the risk of accidents where the rotor is subjected to significant upwind axial *** findings offer valuable insights into mitigating the risk of rotor lifting due to axial forces during PT events in ultra-high head PTs.

关键词： ultra-high head pump-turbine pump power-trip unbalanced impeller forces pressure pulsations flow pattern transitions

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Impregnating photo-stable gold precursor onto uncalcined TS-1 to boost catalytic hydro-oxidation of propane

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science China Chemistry 2025年第4期68卷 1585-1596页

作者： Zhihua Zhang Erchuan Yang Fan Liu Kesheng Xu Yuxia Zhong Jinwei Sun Shudong Shi Xuezhi Duan Xinggui Zhou State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China

Immobilizing highly dispersed Au nanoparticles onto titanium silicalite-1(TS-1)by a simple impregnation method under light is still a challenging *** this work;a high photostable Au precursor protected by thiol ligands was firstly synthesized;and the as-prepared Au precursor displayed excellent stability under light for over 30 days;while the Au precursor without thiol ligands formed precipitates after just 2 h under ***;the Au precursor protected by thiol ligands was immobilized on the external surface of uncalcined TS-1(i.e.;TS-1-B)by the incipient wetness impregnation method(IWI method)to prepare Au/TS-1-B *** activity of as-prepared Au/TS-1-B catalyst in the hydro-oxidation of propane to acetone was 1.4 times higher than that of the catalyst prepared by the deposition-precipitation urea method(DPU method).The structures of the Au/TS-1-B catalysts prepared by different methods were analyzed by multiple *** to the Au/TS-1-B catalyst prepared by the DPU method;the Au/TS-1-B catalyst synthesized by the IWI method exhibited a narrower size distribution of Au nanoparticles and had more small Au particles(<2 nm);which is the main reason for its superior ***;the effects of gold loadings;reaction temperature and Si/Ti molar ratio on the catalytic performance of the Au/TS-1-B catalyst prepared by the IWI method were also *** addition;the Au/TS-1-B catalyst prepared by the IWI method also exhibited excellent stability for over 140 h.

关键词： hydro-oxidation of propane acetone Au-Ti bifunctional catalysts IWI method thiol ligands stability

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Effect of introducing oxygen into ethylene tar pitches on their carbonaceous products

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Chinese Journal of Chemical engineering 2024年第12期76卷 135-146页

作者： Rongqi Chen Yongzheng Zhang Yanli Wang Chunyin Shen Liang Zhan Licheng Ling State Key Laboratory of Green Chemical Engineering and Industrial Catalysis Key Laboratory of Specially Functional Polymeric Materials and Related Technology(Ministry of Education)Shanghai Key Laboratory of Multiphase Materials Chemical EngineeringState Key Laboratory of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China

Ethylene tar is a prospective precursor for preparing carbonaceous materials,which is regarded as a representative soft carbon material after ***,the introduction of oxygen can influence the morphology of the final carbonaceous *** the introduction of oxygen,dealkylation and dehydrogenation will be promoted and the molecules can be linked more *** the subsequent carbonization,the biphenyl structures caused by the deoxygenation via the elimination of CO_(2),as well as the reserved aromatic ether bonds,can facilitate the strong cross-linking,which will restrain the movement of the carbon layers and the formation of the graphitic *** the graphitization treatment at 2800℃,the oxidized pitch can lead to short-range ordered and long-range unordered structures,while the sample without oxidation can result in long-range ordered graphitic *** can be proved that a simple oxidation-carbonization treatment can transform ethylene tar into hard carbon structures.

关键词： Fuel Oxidation Ethylene tar pitch Carbonization Hard carbon Chemical processes

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Robust enhancement of valley polarization and quantum yield in composition grading lateral heterostructure of MoS2-WS2 monolayer

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Progress in Natural science:Materials International 2024年第1期34卷 187-193页

作者： Mengke Kang Cheng Zhang Congpu Mu Kun Zhai Tianyu Xue Bochong Wang Fusheng Wen Yingchun Cheng Jianyong Xiang Jun-Feng Dai Anmin Nie Zhongyuan Liu Center for High Pressure Science State Key Laboratory of Metastable Materials Science and Technology Yanshan University Shenzhen Institute for Quantum Science and Engineering and Department of Physics Southern University of Science and Technology Shenzhen Key Laboratory of Quantum Science and Engineering

Valley degeneracy can be broken owing to the strong spin-orbit coupling in two-dimensional transition metal dichalcogenides（2D-TMDCs）. Valley-dependent interaction of carriers in TMDCs with different circular polarizations of light offers valley degree-of-freedom besides charge and spin to carry information. Thus, bandgap engineering of 2D-TMDCs plays a critical role in developing practical valleytronic devices. Hereby, we demonstrate a great enhancement in quantum yield as well as polarization of monolayer MoS2achieved by gradually alloying W atoms in MoS2. By appropriately setting a time offset between the evaporation of MoO3and WO3precursors during chemical vapor deposition, a compositionally graded heterostructure of MoS2-WS2monolayer can be readily grown at large scale. Raman and transmission electron microscopy measurements demonstrate that the interface possesses a steep gradient in composition, spanning from MoS2to WS2over a length ～2 μ*** to pure monolayer MoS2, the photoluminescence intensity at the compositionally graded interface of Mo1-xWxS2was observed to increase by a factor of 16 owing to the effective separation of photogenerated carriers by the built-in electric field. Particularly, a remarkably high polarization of 70% at 16 K is demonstrated for the compositionally graded interface of Mo1-xWxS2, which is ～1.4 times larger than that in MoS2and is attributed to the combined effect of the alloyed structure and graded bandgap. Such an engineering scheme with a graded bandgap offers new approach for the development of high-efficiency valleytronics devices.

关键词： Transition metal dichalcognide monolayer Compositionally graded in-plane heterostructure Chemical vapor deposition Valley polarization Quantum yield

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Computational study of the effect of friction coefficients and particle shape on the repose angle and porosity of sinter piles

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Particuology 2025年第3期98卷 231-240页

作者： Meng Li Yaowei Yu Henrik Saxén Process and Systems Engineering Laboratory Faculty of Science and EngineeringÅbo Akademi University20500TurkuFinland State Key Laboratory of Advanced Special Steel Shanghai Key Laboratory of Advanced FerrometallurgySchool of Materials Science and EngineeringShanghai University200444ShanghaiChina

Shape has an undeniable impact on particle behaviour,and the shapes of naturally occurring granular matter are typically *** studies of irregularly shaped particles are challenging but necessary to gain a better understanding of the flow of particulate *** study focuses on the behaviour of irregular sinter particles and applies the discrete element method to examine the effects of static and rolling friction coefficients and particle shape on the angle of repose and porosity of sinter piles.A three-dimensional model of an irregular sinter particle reconstructed by close-range photogrammetry served as the template for generating multi-sphere particles with varying numbers of sub-spheres(1,3,7,22,and 135)and sphericity ranging from 1 to *** of particle piles were conducted for a range of values of the coefficients of static and rolling *** results indicate that the angle of repose increases with static friction and also increases with rolling friction coefficient when it is lower than the static *** angle of repose shows clear dependence on particle shape,particularly for lower rolling friction *** friction coefficients for particles of five different shapes were individually determined through bulk calibration,and irregularly shaped particles in DEM were found to require lower friction *** was marginally affected by the static and rolling friction coefficients for spherical particles,while non-spherical particles showed porosity increasing with the rolling friction *** relationship between particle sphericity and porosity was nonlinear:as sphericity decreases from 1.00 to 0.69,the porosity first decreases to a minimum and then *** findings confirmed that both friction and particle shape have a significant influence on the structure of sinter piles,with implications for material handling and processing in industrial applications.

关键词： Sinter Discrete element method Friction coefficients Particle shape Repose angle Porosity

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