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Flash‑Induced High‑Throughput Porous Graphene via Synergistic Photo‑Effects for Electromagnetic Interference Shielding

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纳微快报:英文版 2023年第11期15卷 1-18页

作者： Jin Soo Lee Jeong‑Wook kim Jae Hee Lee Yong Koo Son young bin kim Kyoohee Woo Chanhee Lee Il‑Doo kim Jae young Seok Jong Won Yu Jung Hwan Park Keon Jae Lee Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak‑roYuseong‑guDaejeon 34141Republic of Korea School of Electrical Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak‑roYuseong‑guDaejeon 34141Republic of Korea Department of Printed Electronics Nano‑Convergence Manufacturing Systems Research DivisionKorea Institute of Machinery and Materials(KIMM)156 Gajeongbuk‑RoYuseong‑GuDaejeon 34103Republic of Korea Department of Mechanical System Design Engineering Seoul National University of Science and Technology232 Gongneung‑roNowon‑guSeoul 01811Republic of Korea Department of Mechanical Engineering(Department of Aeronautics Mechanical and Electronic Convergence Engineering)Kumoh National Institute of Technology61 Daehak‑roGumiGyeongbuk 39177Republic of Korea

Porous 2D materials with high conductivity and large surface area have been proposed for potential electromagnetic interference(EMI)shielding materials in future mobility and wearable applications to prevent signal noise,transmission inaccuracy,system malfunction,and health ***,we report on the synthesis of lightweight and flexible flash-induced porous graphene(FPG)with excellent EMI shielding *** broad spectrum of pulsed flashlight induces photo-chemical and photo-thermal reactions in polyimide films,forming 5×10 cm^(2)-size porous graphene with a hollow pillar structure in a few *** resulting material demonstrated low density(0.0354 g cm^(−3))and outstanding absolute EMI shielding effectiveness of 1.12×10^(5) dB cm^(2) g^(−1).The FPG was characterized via thorough material analyses,and its mechanical durability and flexibility were confirmed by a bending cycle ***,the FPG was utilized in drone and wearable applications,showing effective EMI shielding performance for internal/external EMI in a drone radar system and reducing the specific absorption rate in the human body.

关键词： Porous graphene Flash lamp Photo-pyrolysis High-throughput Electromagnetic interference shielding

Strengthening mechanisms analysis and tailoring of bimodal grain structures for enhanced strength in CoCrFeMnNi high-entropy alloys

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Rare Metals 2024年第8期43卷 3893-3903页

作者： Jaesoung Lee Seulgi kim Taehyun Kwon young II kim Suyeon kim Sung Ho Song bin Lee Dongju Lee Department of Urban Energyand Environmental Engineering Chungbuk National University Division of Advanced Materials Engineering Kongju National University Department of Advanced Materials Engineering for Information and Electronics Integrated-Education Institute for Frontier Science and Technology (BK21 Four)Kyung Hee University

The CoCrFeMnNi high-entropy alloys(HEAs)with a(face-centered cubic) FCC structure has garnered considerable attention for its exceptional ductility and strain hardening ***,its yield strength is insufficient for structural *** this study,strengthening mechanisms in these HEAs were investigated to gain insight into the mechanical properties according to alloy powder ***,we present a novel approach to achieve both high strength and high ductility through the creation of a bimodal structure consisting of both coarse and fine grains via gas atomization and spark plasma sintering processes.A bimodally structured HEA prepared with a mass ratio of 2:8 between coarse particles(75-106 μm) and fine particles(≤25 μm)yielded optimal results,with a strength of 491.95 MPa and elongation of 19.64%.This strength value represents an～41% increase compared with the sample that displayed a fine single microstructure(347.08 MPa for yield strength).The strength enhancement was attributed to the prevention of plastic deformation initiation from the fine particles during *** innovative approach to the creation of HEAs with bimodal structures shows promise for various applications,such as structural components that require a combination of high strength and high ductility.

关键词： High-entropy alloys CrCoFeMoNi Bimodal Gas atomization Mechanical properties

Effect of pulse time on surface characteristics and corrosion resistance during pulse electrochemical polishing

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中国有色金属学会会刊：英文版 2012年第S3期22卷 876-880页

作者： young-bin kim Jeong-Woo PARK Department of Advanced Parts and Materials Engineering Chosun University Department of Mechanical Design Engineering Chosun University

Pulse electrochemical polishing (PECP) was used to improve the mechanical properties,such as surface roughness and corrosion resistance,of conductive metallic *** can provide a smooth,bright,reflective,and deburred surface that exhibits superior corrosion *** this work,stainless steel was used as the anode,and copper was used as the cathode due to their low electrical *** surface roughness of the PECP sample was measured by atomic force microscopy (AFM).A scanning electron microscope (SEM) was used to observe surface characteristics,and an Auger electron spectroscope (AES) was used to analyze the metallurgical composition and thickness of the passive *** aim of this research was to compare the corrosion resistance rates of the unprocessed and PECP-processed stainless steel.

关键词： stainless stell pulse electrochemical polishing corrosion resistance

Hyperreflective photonic crystals created by shearing colloidal dispersions at ultrahigh volume fraction

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Microsystems & Nanoengineering 2024年第1期10卷 161-173页

作者： Minji kim Jong bin kim Shin-Hyun kim Department of Chemical and Biomolecular Engineering Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea

Colloidal crystallization serves as one of the most economic and scalable production methods for photonic ***,insufficient optical performance,nonuniformity and low reproducibility remain challenges for advanced high-value *** this study,we optimally formulate a photocurable dispersion of silica particles and apply shear flow to unify the orientation of the colloidal crystals,ensuring high optical performance and *** silica particles experience strong repulsion at ultrahigh volume fractions of 50%but demonstrate low mobility,leading to polycrystalline *** shear flow to the dispersions allows the silica particles to rearrange into larger crystalline domains with a unidirectional orientation along the *** shear-induced structural change produces absolute reflectivity at the stopband as high as 90%and a high transparency of 90%at off-resonant wavelengths with minimal diffusive ***,the strong interparticle repulsion ensures a uniform volume fraction of particles throughout the dispersion,reducing deviations in the optical *** intricately micropattern the photocurable dispersions using ***,the photonic films and patterns can be stacked to form multiple layers,displaying mixed structural colors and multiple reflectance peaks without sacrificing *** superior photonic materials hold promise for various optical applications,including optical components and anticounterfeiting patches.

关键词： properties. dispersion reflectivity

Integration of earth-abundant cocatalysts for high-performance photoelectrochemical energy conversion

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Journal of Energy Chemistry 2024年第1期88卷 336-355,I0008页

作者： Joonhee Ma Sang Hyun Ahn Soo young kim Department of Materials Science and Engineering Korea UniversitySeoul 02841Republic of Korea School of Chemical Engineering and Materials Science Chung-Ang University84 Heukseok-roDongjak-guSeoul 06974Republic of Korea

Photoelectrochemical(PEC)energy conversion has emerged as a promising and efficient approach to sustainable energy harvesting and *** utilizing semiconductor photoelectrodes,PEC devices can harness solar energy and drive electrochemical reactions such as water splitting or carbon dioxide(CO_(2))reduction to generate clean fuels and value-added ***,PEC energy conversion faces several challenges such as high overpotential,sluggish reaction kinetics,charge carrier recombination,and stability issues,which limit its practical ***,significant research has been conducted to improve the overall conversion efficiency of PEC *** particularly promising approach is the use of cocatalysts,which involves introducing specific cocatalysts onto the photoelectrode surface to promote charge separation,improve reaction kinetics,and reduce the overpotential,thereby enhancing the overall performance of PEC energy *** review provides a comprehensive overview of the recent developments in the earth-abundant cocatalysts for PEC water splitting and CO_(2) *** main earth-abundant catalysts for the PEC water splitting include transition-metal dichalcogenide(TMD)-based materials,metal phosphides/carbides,and metal oxides/***,PEC-CO_(2)RR was divided into C_(1) and C_(2+)based on the final product since various products could be produced,focusing on diverse earth-abundant materials-based *** addition,we provide and highlight key advancements achieved in the very recent reports on novel PEC system design engineering with ***,the current problems associated with PEC systems are discussed along with a suggested direction to overcome these obstacles.

关键词： Solar energy Photo-electrochemical Water splitting CO_(2)reduction Cocatalysts

Hydrangea serrata extract exerts tumor inhibitory activity against hepatocellular carcinoma HepG2 cells via inducing p27/CDK2-mediated cell cycle arrest and apoptosis

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Asian Pacific Journal of Tropical Biomedicine 2024年第2期14卷 65-72,I0002-I0005页

作者： Ye-eun kim Jeonghye Hwang Ki-young kim Graduate School of Biotechnology Kyung Hee UniversitySeocheonGiheungYonginGyeonggi-do 446-701Republic of Korea Department of Genetics and Biotechnology College of Life SciencesKyung Hee UniversitySeocheonGiheungYonginGyeonggi-do 446-701Republic of Korea

Objective:To examine the inhibitory effect of Hydrangea serrata extract against hepatocellular carcinoma HepG2 cells and its underlying ***:The effects of Hydrangea serrata extract on growth inhibition of tumor cells and spheroids were assessed using MTT and 3D culture *** real-time PCR and Western blot analyses were employed to investigate the changes in mRNA and protein expression levels of molecules related to cell cycle and ***:Hydrangea serrata extract effectively inhibited the growth of both tumor cells and *** extract also significantly upregulated p27 mRNA expression and downregulated CDK2 mRNA expression,leading to cell cycle ***,increased BAX/Bcl-2 ratio as well as caspase-9 and-3 were observed after treatment with Hydrangea serrata extract,indicating the induction of tumor cell ***:Hydrangea serrata extract has the potential to alleviate tumors by effectively modulating cell-cycle-related gene expressions and inducing apoptosis,thereby inhibiting tumor growth.

关键词： Hydrangea serrata Hepatocellular carcinoma Liver cancer Anticancer Cell cycle arrest Apoptosis

Factors affecting length of stay according to bronchopulmonary dysplasia severity:a nationwide cohort study in Korea

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World Journal of Pediatrics 2024年第5期20卷 470-480页

作者： Hye Mi Lee Jeongmin Shin Sae Yun kim So young kim Department of Pediatrics College of MedicineThe Catholic University of KoreaSeoulRepublic of Korea Department of Pediatrics Yeouido St.Mary’s HospitalCollege of MedicineThe Catholic University of Korea1063-roYeongdeungpo-guSeoul07345Republic of Korea

Background Longer hospitalizations for preterm infants with bronchopulmonary dysplasia(BPD)delay developmental outcomes,increase the risk for hospital-acquired complications,and exert a substantial socioeconomic *** study aimed to identify factors associated with an extended length of stay(LOS)at different levels of severity of *** A cohort study was conducted using the Korean Neonatal Network registry of very low birth weight infants with BPD between 2013 and 2017 through retrospective *** A total of 4263 infants were diagnosed with *** mild BPD,infants requiring surgical treatment for patent ductus arteriosus needed a longer LOS[eadjustedβcoefficients(adjβ)1.041;95%confidence interval(CI):0.01–0.08]and hydrocephalus(eadjβ1.094;95%CI 0.01–0.17).In moderate BPD,infants administered steroids or with intraventricular hemorrhage required a longer LOS(eadjβ1.041;95%CI 0.00–0.07 and eadjβ1.271;95%CI 0.11–0.38,respectively).In severe BPD,infants with comorbidities required a longer LOS:pulmonary hypertension(eadjβ1.174;95%CI 0.09–0.23),administrated steroid for BPD(eadjβ1.116;95%CI 0.07–0.14),sepsis(eadjβ1.062;95%CI 0.01–0.11),patent ductus arteriosus requiring surgical ligation(eadjβ1.041;95%CI 0.00–0.08),and intraventricular hemorrhage(eadjβ1.016;95%CI 0.05–0.26).Additionally,the higher the clinical risk index score,the longer the LOS needed for infants in all *** The factors affecting LOS differed according to the severity of *** approaches to reducing LOS may be devised using knowledge of the various risk factors affecting LOS by BPD severity.

关键词： Bronchopulmonary dysplasia Length of stay Very low birth weight

MXene-based hybrid materials for electrochemical and photoelectrochemical H_(2) generation

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Journal of Energy Chemistry 2024年第6期93卷 111-125,I0004页

作者： Jun young kim Seung Hun Roh Chengkai Xia Uk Sim Jung Kyu kim School of Material Science and Engineering North University of ChinaTaiyuan 030051China School of Chemical Engineering Sungkyunkwan University(SKKU)2066Seobu-roJangan-guSuwon 16419Republic of Korea Hydrogen Energy Technology Laboratory Korea Institute of Energy Technology(KENTECH)NajuJeollanamdo 58330Republic of Korea SKKU Advanced Institute of Nano Technology(SAINT) Sungkyunkwan University(SKKU)2066Seobu-roJangan-guSuwon 16419Republic of Korea

The conversion of solar energy to produce clean hydrogen fuel through water splitting is an emerging strategy for efficiently storing solar energy in the form of solar *** aligns with the increasing global demand for the development of an ideal energy alternative to fossil fuels that does not emit greenhouse ***(EC) and photoelectrochemical(PEC) water splitting technologies have garnered significant attention worldwide for advanced hydrogen solar fuel production in recent *** achieve sustainable green H_(2) production,it is essential to create efficient catalyst materials that are low-cost and can replace expensive noble metal-based *** characteristics make them an ideal catalyst material for the ***-dimensional MXenes with M_(n+1)X_(n) structure have been identified as a promising option for EC and PEC water splitting due to their superior hydrophilicity,metal-like conductivity,large surface area,and adjustable surface ***,we present a summary of recent advancements in the synthesis and performance enhancement methods for MXene hybrid materials in hydrogen production through EC and PEC water ***,we examine the challenges and insights associated with the rational design of MXene-based hybrid materials to facilitate efficient water splitting for sustainable solar fuel production.

关键词： MXene Hybrid materials EC PEC HER OER Water splitting

Advances in advanced solution-synthesis-based structural materials for tactile sensors and their intelligent applications

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InfoMat 2024年第1期6卷 31-64页

作者： Hongsen Niu Ning Li Eun-Seoung kim young Kee Shin Nam-young kim Guozhen Shen Yang Li School of Information Science and Engineering University of JinanJinanthe People's Republic of China RFIC Centre Department of Electronics EngineeringKwangwoon UniversitySeoulRepublic of Korea Department of Molecular Medicine and Biopharmaceutical Sciences Seoul National UniversitySeoulRepublic of Korea School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijingthe People's Republic of China School of Microelectronics Shandong UniversityJinanthe People's Republic of China

Intelligent applications,with tactile sensors at their core,represent significant advancement in the field of artificial ***,achieving perception abilities in tactile sensors that match or exceed human skin remains a formidable ***,the design and implementation of hierarchical structural materials are considered the optimal solution to this *** contrast to conventional methods,such as complicated lithography and three-dimensional printing,the cost-effective and scalable nature of advanced solution-synthesis methods makes them ideal for preparing diverse tactile sensors with hierarchical structural ***,the process and applicability of advanced solution synthesis methods have yet to form a seamless ***,the development and intellectualization of tactile sensors based on advanced solution synthesis methods are still in their early stages,and require a comprehensive and systematic review to usher in *** study delves into the advantages and disadvantages of various advanced solution synthesis methods,providing detailed ***,the positive effects of hierarchical structural materials constructed using these methods in tactile sensors and their intelligent applications are also discussed in ***,the challenges and future opportunities faced by this emerging field are summarized.

关键词： aqueous phase reduction artificial intelligence hydrothermal growth in situ polymerization tactile sensor