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Journal of Rock Mechanics and Geotechnical Engineering 2023年第12期15卷 3221-3229页

作者： Juhyi Yim Yoonsung Lee Seungki Hong ki-bok min R&D Center Hyundai Engineering and Construction75Yulgok-roJongno-guSeoulRepublic of Korea Department of Energy Systems Engineering and Research Institute of Energy and Resources Seoul National University1Gwanak-roGwanak-guSeoul08826Republic of Korea

To improve the accuracy of indirect tensile strength for a transversely isotropic rock in the Brazilian test, this study considered the three-dimensional (3D) deformation and the nonlinear stress–strain relationship. A parametric study of a numerical Brazilian test was performed for a general range of elastic constants, revealing that the 3D modeling evaluated the indirect tensile strength up to 40% higher than the plane stress modeling. For the actual Asan gneiss, the 3D model evaluated the indirect tensile strength up to 10% higher and slightly enhanced the accuracy of deformation estimation compared with the plane stress model. The nonlinearity in stress–strain curve of Asan gneiss under uniaxial compression was then considered, such that the evaluated indirect tensile strength was affected by up to 10% and its anisotropy agreed well with the physical intuition. The estimation of deformation was significantly enhanced. The further validation on the nonlinear model is expected as future research.

关键词： Anisotropy Transversely isotropy Brazilian test Indirect tensile strength Nonlinearity 3D modeling

Interactive roles of geometrical distribution and geomechanical deformation of fracture networks in fluid flow through fractured geological media

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第4期12卷 780-792页

作者： Qinghua Lei Xiaoguang Wang ki-bok min Jonny Rutqvist Department of Earth Sciences ETH ZürichZürichSwitzerland Laboratoire HydroSciences Montpellier Universite de MontpellierMontpellierFrance Department of Energy Systems Engineering Seoul National UniversitySeoulRepublic of Korea Energy Geosciences Division Lawrence Berkeley National LaboratoryBerkeleyUSA

In this study,the combined effects of geometrical distribution and geomechanical deformation of fracture networks on fluid flow through fractured geological media are investigated *** consider a finite-sized model domain in which the geometry of fracture systems follows a power-law length *** geomechanical response of the fractured rock is simulated using a hybrid finitediscrete element model,which can capture the deformation of intact rocks,the interaction of matrix blocks,the displacement of discrete fractures and the propagation of new *** far-field stress loading,the locally variable stress distribution in the fractured rock leads to a stress-dependent variable aperture field controlled by compression-induced closure and shear-induced dilatancy of rough *** equivalent permeability of the deformed fractured rock is calculated by solving for the fracture-matrix flow considering the cubic relationship between fracture aperture and flow rate at each local fracture *** report that the geometrical connectivity of fracture networks plays a critical role in the hydromechanical processes in fractured rocks.A well-connected fracture system under a high stress ratio condition exhibits intense frictional sliding and large fracture dilation/opening,leading to greater rock mass ***,a disconnected fracture network accommodates much less fracture shearing and opening,and has much lower bulk *** further propose an analytical solution for the relationship between the equivalent permeability of fractured rocks and the connectivity metric(*** parameter)of fracture networks,which yields an excellent match to the numerical *** infer that fluid flow through a well-connected system is governed by traversing channels(forming an“in parallel”architecture)and thus equivalent permeability is sensitive to stress loading(due to stress-dependent fracture permeability),whilst fluid flow through a discon

关键词： Fracture Stress Aperture Connectivity Permeability

Comparison of numerical codes for coupled thermo-hydro-mechanical simulations of fractured media

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第4期12卷 850-865页

作者： Ahmad Zareidarmiyan Hossein Salarirad Victor Vilarrasa Kwang-Il kim Jaewon Lee ki-bok min Department of mining Engineering Amirkabir University of Technology-Tehran Polytechnic(AUT)TehranIran Institute of Environmental Assessment and Water Research(IDAEA) Spanish National Research Council(CSIC)BarcelonaSpain Associated Unit:Hydrogeology Group UPC-CSIC BarcelonaSpain Department of Energy Resources Engineering Seoul National UniversitySeoulRepublic of Korea Radioactive Waste Disposal Research Division Korea Atomic Energy Research Institute(KAERI)DaejeonRepublic of Korea

Geo-energy and geo-engineering applications,such as improved oil recovery(IOR),geologic carbon storage,and enhanced geothermal systems(EGSs),involve coupled thermo-hydro-mechanical(THM)processes that result from fluid injection and *** some cases,reservoirs are highly fractured and the geomechanical response is controlled by ***,fractures should explicitly be included into numerical models to realistically simulate the THM responses of the *** this study,we perform coupled THM numerical simulations of water injection into naturally fractured reservoirs(NFRs)using CODE_BRIGHT and TOUGH-UDEC ***_BRIGHT is a finite element method(FEM)code that performs fully coupled THM analysis in geological media and TOUGH-UDEC sequentially solves coupled THM processes by combining a finite volume method(FVM)code that solves nonisothermal multiphase flow(TOUGH2)with a distinct element method(DEM)code that solves the mechanical problem(UDEC).First,we validate the two codes against a semi-analytical solution for water injection into a single deformable fracture considering variable permeability based on the cubic ***,we compare simulation results of the two codes in an idealized conceptual model that includes one horizontal fracture and in a more realistic model with multiple *** code models fractures *** calculates fracture deformation from the fracture normal and shear stiffnesses,while CODE_BRIGHT treats fractures as equivalent porous media and uses the equivalent Young’s modulus and Poisson’s ratio of the ***,we obtain comparable results of pressure,temperature,stress and displacement distributions and evolutions for the single horizontal fracture *** some similarities,the two codes provide increasingly different results as model complexity *** differences highlight the challenging task of accurately modeling coupled THM processes in fractured media given their high nonlineari

关键词： Coupled thermo-hydro-mechanical(THM) analysis Improved oil recovery(IOR) Naturally fractured reservoir(NFR) CODE_BRIGHT TOUGH-UDEC

Synergistically enhanced ORR and HER performance on Co-N-C coupled in-situ generated PtCo intermetallic

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Journal of Energy Chemistry 2025年第1期100卷 721-729页

作者： Guanyu Luo min Song Lulu An Xiao Huang Qian Zhang Chenhao Zhang Tao Shen Shuang Wang Deli Wang Key Laboratory of Material Chemistry for Energy Conversion and Storage (Huazhong University of Science and Technology) ministry of Education School of Chemistry and Chemical Engineering Huazhong University of Science and Technology

Integrating multi-scale sites in a composite catalyst is vital to realize efficient ***,a synergistic composite catalyst consisting of Co atomic sites and in-situ generated PtCo intermetallic compounds （IMCs）(o-PtCo@CoNC) is proposed through Co pre-anchoring and subsequent impregnation-reduction *** loading of Co atoms provides a chance for in-situ generating PtCo ordered intermetallic *** remaining Co single atoms and PtCo IMCs construct synergistic electrocatalytic *** from the ordered structure,synergistic effect of Pt Co IMCs and Co single atoms,o-PtCo@CoNC exhibits excellent electrocatalytic performance for oxygen reduction reaction （ORR） and hydrogen evolution reaction （HER） with mass activity of 1.21 A mgPt-1（at 0.9 V） and5.70 A mgPt-1（at an overpotential of 100 mV）,***,o-PtCo@CoNC delivers negligible loss of half-wave potential and overpotential during long-term stability test in acid solutions,with 13 mV decay after 50,000 potential cycles for ORR and a 2.7 mV decay after 20,000 potential cycles for *** integration strategy of single-atomic sites coupled IMCs paves the way for enhancing the activity and durability of Pt-based electrocatalysts.

关键词： Electrolytic reduction

Porous Organic Cage‑Based Quasi‑Solid‑State Electrolyte with Cavity‑Induced Anion‑Trapping Effect for Long‑Life Lithium Metal Batteries

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Nano-Micro Letters 2025年第2期17卷 376-386页

作者： Wei-min Qin Zhongliang Li Wen‑Xia Su Jia‑min Hu Hanqin Zou Zhixuan Wu Zhiqin Ruan Yue‑Peng Cai Kang Li Qifeng Zheng School of Chemistry South China Normal UniversityGuangzhou 510006People’s Republic of China Key Laboratory of Functional Metal‑Organic Compounds of Hunan Province College of Chemistry and Material ScienceHengyang Normal UniversityHengyang 421008People’s Republic of China Guangzhou Key Laboratory of Energy Conversion and Energy Storage Materials Guangzhou 510006People’s Republic of China

Porous organic cages(POCs)with permanent porosity and excellent host–guest property hold great potentials in regulating ion transport behavior,yet their feasibility as solid-state electrolytes has never been testified in a practical ***,we design and fabricate a quasi-solid-state electrolyte(QSSE)based on a POC to enable the stable operation of Li-metal batteries(LMBs).Benefiting from the ordered channels and cavity-induced anion-trapping effect of POC,the resulting POC-based QSSE exhibits a high Li+transference number of 0.67 and a high ionic conductivity of 1.25×10^(−4) S cm^(−1) with a low activation energy of 0.17 *** allow for homogeneous Li deposition and highly reversible Li plating/stripping for over 2000 *** a proof of concept,the LMB assembled with POC-based QSSE demonstrates extremely stable cycling performance with 85%capacity retention after 1000 ***,our work demonstrates the practical applicability of POC as SSEs for LMBs and could be extended to other energy-storage systems,such as Na and K batteries.

关键词： Porous organic cage Cavity-induced anion-trapping Quasi-solid-state electrolyte Homogeneous Li+flux Lithium metal battery

Automated X-ray Defect Inspection on Occluded BGA Balls Using Hybrid Algorithm

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Computers, Materials & Continua 2023年第6期75卷 6337-6350页

作者： ki-Yeol Eom Byungseok min Department of AI Bigdata Suseong UniversityDaegu42078Korea R&D Center XAVIS Co.Ltd.Seongnam-si13202Korea

Automated X-ray defect inspection of occluded objects has been an essential topic in semiconductors,autonomous vehicles,and artificial intelligence ***,there are few solutions to segment occluded objects in the X-ray inspection *** particular,in the Ball Grid Array inspection of X-ray images,it is difficult to accurately segment the regions of occluded solder balls and detect defects inside solder *** this paper,we present a novel automatic inspection algorithm that segments solder balls,and detects defects fast and efficiently when solder balls are *** proposed algorithm consists of two *** the first stage,the defective candidates or defects are determined through the following four steps:(i)image preprocessing such as noise removal,contrast enhancement,binarization,connected component,and morphology,(ii)limiting the inspec-tion area to the ball regions and determining if the ball regions are occluded,(iii)segmenting each ball region into one or more regions with similar gray values,and(iv)determining whether there are defects or defective candidates in the regions using a weighted sum of local threshold on local *** there are defective candidates,the determination of defects is finally made in the following *** the second stage,defects are detected using the automated inspection technique based on oblique computed *** 3D precision inspection process is divided into four steps:(i)obtaining 360 projection images(one image per degree)rotating the object from 0 to 360 degrees,(ii)reconstructing a 3D image from the 360 projected images,(iii)finding the center slice of gravity for solder balls from the axial slice images in the z-direction,and getting the inspection intervals between the upper bound and the lower bound from the center slice,and(iv)finally determining whether there are defects in the averaged image of solder *** proposed hybrid algorithm is robust for segmenting the defects inside o

关键词： Hybrid voids BGA X-ray inspection defects

Longitudinal assessment of peripheral organ metabolism and the gut microbiota in an APP/PS1 transgenic mouse model of Alzheimer’s disease

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Neural Regeneration Research 2025年第10期20卷 2982-2997页

作者： Hongli Li Jianhua Huang Di Zhao Lemei Zhu Zheyu Zhang min Yi Weijun Peng Department of Integrated Traditional Chinese&Western Medicine The Second Xiangya HospitalCentral South UniversityChangshaHunan ProvinceChina National Clinical Research Center for Metabolic Diseases ChangshaHunan ProvinceChina Hunan Academy of Chinese Medicine ChangshaHunan ProvinceChina Academician Workstation Changsha Medical UniversityChangshaHunan ProvinceChina

Alzheimer’s disease not only affects the brain,but also induces metabolic dysfunction in peripheral organs and alters the gut *** aim of this study was to investigate systemic changes that occur in Alzheimer’s disease,in particular the association between changes in peripheral organ metabolism,changes in gut microbial composition,and Alzheimer’s disease *** do this,we analyzed peripheral organ metabolism and the gut microbiota in amyloid precursor protein-presenilin 1(APP/PS1)transgenic and control mice at 3,6,9,and 12 months of ***-month-old APP/PS1 mice exhibited cognitive impairment,Alzheimer’s disease-related brain changes,distinctive metabolic disturbances in peripheral organs and fecal samples(as detected by untargeted metabolomics sequencing),and substantial changes in gut microbial composition compared with younger APP/PS1 ***,a strong correlation emerged between the gut microbiota and kidney metabolism in APP/PS1 *** findings suggest that alterations in peripheral organ metabolism and the gut microbiota are closely related to Alzheimer’s disease development,indicating potential new directions for therapeutic strategies.

关键词： Alzheimer’s disease APP/PS1 mice brain-kidney axis gut microbiota heart-brain axis liver-brain axis lung-brain axis microbiota-gut-brain axis peripheral organ metabolism spleen-brain axis

Visually meaningful image encryption algorithm based on digital signature

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Digital Communications and Networks 2023年第1期9卷 159-165页

作者： Xiaoling Huang Youxia Dong Guodong Ye Wun-She Yap bok-min Goi Faculty of Mathematics and Computer Science Guangdong Ocean UniversityZhanjiang524088China Lee Kong Chian Faculty of Engineering and Science Universiti Tunku Abdul RahmanJalan Sungai LongCheras43000SelangorMalaysia

Traditional image encryption algorithms transform a plain image into a noise-like *** lower the chances for the encrypted image being detected by the attacker during the image transmission,a visually meaningful image encryption scheme is suggested to hide the encrypted image using another carrier *** paper proposes a visually meaningful encrypted image algorithm that hides a secret image and a digital signature which provides authenticity and *** recovered digital signature is used for the purpose of identity authentication while the secret image is encrypted to protect its *** Significant Bit(LSB)method to embed signature on the encrypted image and Lifting Wavelet Transform(LWT)to generate a visually meaningful encrypted image are *** proposed algorithm has a keyspace of 139.5-bit,a Normalized Correlation(NC)value of 0.9998 which is closer to 1 and a Peak Signal to Noise Ratio(PSNR)with a value greater than 50 *** analyses are also performed on the proposed algorithm using different *** experimental results show that the proposed scheme is with high key sensitivity and strong robustness against pepper and salt attack and cropping ***,the histogram analysis shows that the original carrier image and the final visual image are very similar.

关键词： Visually meaningful image encryption Lifting wavelet transform Lorenz system Signature Security

DICE:An Effective Query Result Cache for Distributed Storage Systems

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Journal of Computer Science & Technology 2010年第5期25卷 933-944页

作者： Jun-ki min Member, A CM Mi-Young Lee School of Computer Science and Engineering Korea University of Technology and Education Byeongcheon-myeon Cheonan Chungnam 330-708 Korea Cloud Computing Research Department Electronics and Telecommunications Research Institute (ETRI) Daejeon 305-700 Korea

Due to the proliferation of Internet and Intranet,the distributed storage systems have received a lot of attention. These systems span a large number of machines and store huge amount of data for a lot of *** the distributed storage systems,a row can be directly accessed using a row *** concentrate on a problem of efficient processing of queries whose predicate is on a column but not a row *** this paper,we present a cache management technique,called DICE which maintains query results of range queries to support the next range *** accelerate the search time of the cached query results,we use modified Interval Ski *** addition,we devise a novel cache replacement policy since DICE maintains an interval rather than a data *** our cache replacement policy considers the properties of intervals,our proposed technique is more efficient than traditional buffer replacement *** experimental result demonstrates the efficiency of our proposed technique.

关键词： distributed system range query query caching Interval Skip List cache replacement

Remarkably slow corrosion rate of high-purity Mg microalloyed with 0.05wt% Sc

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Journal of Magnesium and Alloys 2023年第3期11卷 991-997页

作者： Soo-min Baek Jeong-ki kim Du-Won min Sung Soo Park Department of Materials Science and Engineering Ulsan National Institute of Science and TechnologyUlsan 44919Republic of Korea

We report that the corrosion resistance of Mg is significantly improved by adding 0.05wt%*** rates evaluated from weight loss values after room-temperature immersion in 0.6 M NaCl solution for two weeks were 0.27 and 4.0 mm y^(-1)for the high-purity Mg samples with and without microalloyed 0.05wt%Sc,*** beneficial effect of Sc microalloying on the corrosion resistance of Mg is discussed in connection with Sc-induced microstructural modifications.

关键词： Magnesium Microalloying Intermetallic phase Microgalvanic corrosion