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Effect of 1Al addition on deformation behavior of Mg

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Journal of Magnesium and Alloys 2021年第2期9卷 489-498页

作者： Ji Hyun Hwang A.Zargaran Gyeongbae Park O.Lee b.-J.Lee Nack J.kim Center for Advanced Aerospace Materials Pohang University of Science and Technology(POSTECH)PohangSouth Korea

Deformation behavior of 1 Al containing Mg alloy has been investigated in the present *** annealing,the Mg-1 Al alloy shows a typical basal *** compared to the pure Mg having a similar texture and grain size,the Mg-1 Al alloy shows much higher strength and larger *** trace analyses of the tensile strained specimens show that non-basal slips such as pyramidal I and II slips can be easily activated at an early stage of deformation in the Mg-1 Al alloy and the grains in the Mg-1 Al alloy are seen to accommodate a larger degree of deformation than those in the pure Mg at a given *** increasing tensile strain,however,there is a strain localization along the initially formed slip lines of non-basal slips,forming surface steps without activating multiple slip lines.

关键词： Deformation behavior Slip trace analysis Non-basal slip Strain localization Ductility

Trend of Developing Aqueous Liquid and Gel Electrolytes for Sustainable,Safe,and High‑Performance Li‑Ion batteries

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Nano-Micro Letters 2024年第1期16卷 17-34页

作者： Donghwan Ji Jaeyun kim School of Chemical Engineering Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Department of Health Sciences and Technology Samsung Advanced Institute for Health Sciences&Technology(SAIHST)Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea biomedical Institute for Convergence at SkkU(bICS) Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Institute of Quantum biophysics(IQb) Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Present Address:Department of NanoEngineering University of California San DiegoLa JollaSan DiegoCA 92093USA

Current lithium-ion batteries(LIbs)rely on organic liquid electrolytes that pose significant risks due to their flammability and *** potential for environmental pollution and explosions resulting from battery damage or fracture is a critical ***-based(aqueous)electrolytes have been receiving attention as an alternative to organic ***,a narrow electrochemicalstability window,water decomposition,and the consequent low battery operating voltage and energy density hinder the practical use of aqueous ***,developing novel aqueous electrolytes for sustainable,safe,high-performance LIbs remains *** Review first commences by summarizing the roles and requirements of electrolytes–separators and then delineates the progression of aqueous electrolytes for LIbs,encompassing aqueous liquid and gel electrolyte development trends along with detailed principles of the *** aqueous electrolytes are progressed based on strategies using superconcentrated salts,concentrated diluents,polymer additives,polymer networks,and artificial passivation layers,which are used for suppressing water decomposition and widening the electrochemical stability window of water of the *** addition,this Review discusses potential strategies for the implementation of aqueous Li-metal batteries with improved electrolyte–electrode interfaces.A comprehensive understanding of each strategy in the aqueous system will assist in the design of an aqueous electrolyte and the development of sustainable and safe high-performance batteries.

关键词： Lithium-ion battery(LIb) Aqueous electrolyte Gel electrolyte Electrochemical stability window Li dendrite

Vision-based Recognition Algorithm for Up-To-Date Indoor Digital Map Generations at Damaged buildings

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Computers, Materials & Continua 2022年第8期72卷 2765-2781页

作者： Dahyeon kim Chulsu kim Junho Ahn Computer Information Technology Korea National University of TransportationChungju27469Korea Department of Railway Vehicle System Engineering Korea National University of TransportationUiwang16106Korea

When firefighters are engaged in search and rescue missions inside a building at a risk of collapse,they have difficulty in field command and rescue because they can only simplymonitor the situation inside the building utilizing old building drawings or *** propose an efficient solution for fast search and rescue work of firefighters,this study investigates the generation of up-to-date digital maps for disaster sites by tracking the collapse situation,and identifying the information of obstacles which are risk factors,using an artificial intelligence algorithm based on low-cost *** research separates the floor by using the mask regional convolutional neural network(R-CNN)algorithm,and determines whether the passage is collapsed or ***,in the case of a passage that can be searched,the floor pattern of the obstacles that exist on the floor that has not collapsed is analyzed,and obstacles are searched utilizing an image processing ***,we can detect various unknown as well as known ***,the locations of obstacles can be estimated using the pixel values up to the bounding box of an existing detected *** conduct experiments using the public datasets collected by Carnegie Mellon university(CMU)and data collected by manipulating a low-cost robot equipped with a smartphone while roaming five buildings in a *** collected data have various floor patterns for objectivity and obstacles that are different from one *** on these data,the algorithm for detecting unknown obstacles of a verified study and estimating their sizes had an accuracy of 93%,and the algorithm for estimating the distance to obstacles had an error rate of *** this process,we tracked collapsed passages and composed up-to-date digital maps for disaster sites that include the information of obstacles that interfere with the search and rescue work.

关键词： Vision artificial intelligence robot map generation damaged building

CFD-based hull optimization in calm water using adaptive grid deformation method

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Journal of Hydrodynamics 2024年第2期36卷 241-262页

作者： Shuguang Wang Yonghwan kim Department of Naval Architecture and Ocean Engineering Seoul National UniversitySeoulKorea

This paper presents an adaptive grid deformation technique for optimizing ship hull forms using computational fluid dynamics(CFD).The proposed method enables accurate and smooth updates of the hull surface and 3-D CFD grids in response to design *** technique incorporates a two-level point-transformation approach to move the grid points by a few design ***,generic b-splines are utilized to transform grid points according to the displacements of the control points within a defined control *** ensures surface modification accuracy and smoothness,similar to those provided by non-uniform rational ***,radial basis functions are used to interpolate the movements of the control points with a limited set of design *** developed method effectively maintains the mesh quality and simulation *** applying this method to surface and grid adaptation,a regression model is proposed in the form of a second-order polynomial to represent the relationship between the geometric parameters and design *** polynomial is then used to introduce geometric ***,a radial basis function surrogate model for the calm-water resistance is constructed to approximate the objective *** enhanced optimization framework is proposed for CFD–based hull optimization and applied to kVLCC2 to validate its feasibility and efficiency.

关键词： Hull-form optimization adaptive grid deformation ship resistance OpenFOAM radial basis function(RbF)surrogate model

Mechanical properties of high-strength concrete subjected to high temperature by stressed test

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中国有色金属学会会刊：英文版 2009年第B09期19卷 128-133页

作者： Gyu-Yong kim Young-Sun kim Tae-Gyu LEE Division of Architecture Engineering Chun gnam National University

Recently, the effects of high temperature on compressive strength and elastic modulus of high strength concrete were experimentally investigated. The present study is aimed to study the effect of elevated temperatures ranging from 20 ℃ to 700 ℃ on the material mechanical properties of high-strength concrete of 40, 60 and 80 MPa grade. During the strength test, the specimens are subjected to a 25% of ultimate compressive strength at room temperature and sustained during heating, and when the target temperature is reached, the specimens are loaded to failure. The tests were conducted at various temperatures (20-700 ℃) for concretes made with W/b ratios of 46%, 32% and 25%, respectively. The results show that the relative values of compressive strength and elastic modulus decrease with increasing compressive strength grade of specimen.

关键词：高强混凝土高温作用力学性能测试抗压强度温度升高弹性模量强度试验

The solidification of two-phase heterogeneous materials:Theory versus experiment

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Science China(Technological Sciences) 2009年第6期52卷 1688-1697页

作者： kim Tongbeum MOE key Laboratory for Strength and Vibration School AerospaceXi'an Jiaotong University

The solidification behavior of two-phase heterogeneous materials such as close-celled aluminum foams was analytically studied. The proposed analytical model can precisely predict the location of solidification front as well as the full solidification time for a two-phase heterogeneous material composed of aluminum melt and non-conducting air pores. Experiments using distilled water simulating the aluminum melt to be solidified (frozen) were subsequently conducted to validate the analytical model for two selected porosities (ɛ), ɛ=0 and 0.5. Full numerical simulations with the method of finite difference were also performed to examine the influence of pore shape on solidification. The remarkable agreement between theory and experiment suggests that the delay of solidification in the two-phase heterogeneous material is mainly caused by the reduction of bulk thermal conductivity due to the presence of pores, as this is the sole mechanism accounted for by the analytical model for solidification in a porous medium.

关键词： effective thermal conductivity porous materials solidification shape factor

The dynamics of the piglet gut microbiome during the weaning transition in association with health and nutrition

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Journal of Animal Science and biotechnology 2018年第4期9卷 971-979页

作者： Robin b.Guevarra Sang Hyun Hong Jin Ho Cho bo-Ra kim Jiwon Shin Jun Hyung Lee bit Na kang Young Hwa kim Suphot Wattanaphansak Richard E.Isaacson Minho Song Hyeun bum kim Department of Animal Resources Science Dankook UniversityCheonanSouth Korea Division of Food and Animal Sciences Chungbuk National UniversityCheongjuSouth Korea Abbvie bioresearch Center AbbvieWorcesterMAUSA National Institute of Animal Science Rural Development AdministrationWanjuSouth Korea Department of Veterinary Medicine Faculty of Veterinary ScienceChulalongkorn UniversityPathum WanBangkok 10330Thailand Department of Veterinary and biomedical Sciences University of MinnesotaSt.PaulMN 55108USA Division of Animal and Dairy Science Chungnam National UniversityDaejeonSouth Korea

background: Understanding the composition of the microbial community and its functional capacity during weaning is important for pig production as bacteria play important roles in the pig’s health and growth performance. However,limited information is available regarding the composition and function of the gut microbiome of piglets in ***, we performed 16 S rRNA gene and whole metagenome shotgun sequencing of DNA from fecal samples from healthy piglets during weaning to measure microbiome shifts, and to identify the potential contribution of the early-life microbiota in shaping piglet health with a focus on microbial stress responses, carbohydrate and amino acid ***: The analysis of 16 S rR NA genes and whole metagenome shotgun sequencing revealed significant compositional and functional differences between the fecal microbiome in nursing and weaned piglets. The fecal microbiome of the nursing piglets showed higher relative abundance of bacteria in the genus bacteroides with abundant gene families related to the utilization of lactose and galactose. Prevotel a and Lactobacil us were enriched in weaned piglets with an enrichment for the gene families associated with carbohydrate and amino acid metabolism. In addition, an analysis of the functional capacity of the fecal microbiome showed higher abundances of genes associated with heat shock and oxidative stress in the metagenome of weaned piglets compared to nursing ***: Overal, our data show that microbial shifts and changes in functional capacities of the piglet fecal microbiome resulted in potential reductions in the effects of stress, including dietary changes that occur during *** results provide us with new insights into the piglet gut microbiome that contributes to the growth of the animal.

关键词： Metagenomics Microbiome Piglets 16S rRNA Weaning

Aqueous-processable,naphthalene diimide-based polymers for eco-friendly fabrication of high-performance,n-type organic electrolyte-gated transistors

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Science China Chemistry 2022年第5期65卷 973-978页

作者： Dahyun Jeong Min Je kim Seungjin Lee Jin-Woo Lee Youngwoong kim Hyeong Jun kim Jeong Ho Cho bumjoon J.kim Department of Chemical and biomolecular Engineering Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea Department of Chemical and biomolecular Engineering Yonsei UniversitySeoul 03722Republic of Korea Department of Chemical and biomolecular Engineering Sogang UniversitySeoul 04107Republic of Korea

Organic electrolyte-gated transistors(OEGTs) have the benefits of low power consumption and large current ***,the electrical performance of n-type OEGTs lags far behind that of p-type *** this study,we design a series of polymers,P(NDITEG-T) and P(NDIMTEG-T),comprising a naphthalene diimide backbone for n-type charge transport and oligo(ethylene glycol)(OEG) side chains for high ionic conductivity and eco-friendly solution *** incorporation of the OEG chain facilitates the electrochemical doping of the semiconductor by ions to realize high-performance,n-type ***,in OEGTs,P(NDITEG-T) achieves a high electron mobility of 1.0 × 10^(-1) cm^(2) V^(-1) s^(-1),which represents the highest value reported for solution-processed,n-type *** is noted that the fabrication of the OEGTs is achieved by solution processing with eco-friendly ethanol/water mixtures in virtue of the hydrophilic OEG *** work demonstrates the molecular design of the P(NDITEG-T) polymer and its significant ability to produce aqueous-processable,high-performance,and n-type OEGTs.

关键词： organic electrolyte-gated transistors n-type transistors oligo(ethylene glycol)polymers eco-friendly solution process high electron mobility

Super-resolution localization photoacoustic microscopy using intrinsic red blood cells as contrast absorbers

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Light(Science & Applications) 2019年第1期8卷 212-222页

作者： Jongbeom kim Jin Young kim Seungwan Jeon Jin Woo bAIk Seong Hee Cho Chulhong kim Departments of Creative IT Engineering Electrical EngineeringMechanical Engineeringand Interdisciplinary Bioscience and BioengineeringPohang University of Science and Technology(POSTECH)77 Cheongam-roNam-guPohangGyeongbuk 37673Republic of Korea

Photoacoustic microscopy(PAM)has become a premier microscopy tool that can provide the anatomical,functional,and molecular information of animals and humans in ***,conventional PAM systems suffer from limited temporal and/or spatial ***,we present a fast PAM system and an agent-free localization method based on a stable and commercial galvanometer scanner with a custom-made scanning mirror(L-PAM-GS).This novel hardware implementation enhances the temporal resolution significantly while maintaining a high signal-to-noise ratio(SNR).These improvements allow us to photoacoustically and noninvasively observe the microvasculatures of small animals and humans in ***,the functional hemodynamics,namely,the blood flow rate in the microvasculature,is successfully monitored and quantified in *** importantly,thanks to the high SNR and fast b-mode rate(500 Hz),by localizing photoacoustic signals from captured red blood cells without any contrast agent,unresolved microvessels are clearly distinguished,and the spatial resolution is improved by a factor of 2.5 in ***-GS has great potential in various fields,such as neurology,oncology,and pathology.

关键词： resolution absorber scanner