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Preparation and characterization of Li_(4)Ti_(5)O_(12) synthesized using hydrogen titanate nanowire for hybrid super capacitor

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Journal of Advanced Ceramics 2013年第3期2卷 285-290页

作者： jong hyun kim Jung Rag YOON R&D Center Samwha Capacitor Co.Ltd.YonginGyeonggi 449-884R.O.Korea

The electrical characteristics of hybrid super capacitor were evaluated by synthesizing LTO(Li_(4)Ti_(5)O_(12))using TiO_(2) having a hydrogen titanate nanowire *** of the hydrogen titanate nanowire was implemented by using TiO_(2) having size of 60 nm and NaOH,and performing synthesis at 70℃for 6 h with a sonochemical *** compound was synthesized at 150℃for 36 h and at 180℃for 36 h respectively by using the hydrogen titanate nanowire and LiOH·H2O as starting materials with a hydrothermal *** final LTO compound was synthesized at 700℃for 6 h using a solid-state *** a result of manufacturing the hybrid super capacitor using LTO synthesized at 180℃for 36 h with the hydrothermal method,a capacity of 198 mA·h/g has been achieved compared to a theoretical capacity of 172 mA·h/g of existing LTO,and thus,the capacity has been increased by about 13%.Further,such excellent cycle performance has ensured its possibility as a high-capacity capacitor.

关键词： LTO(Li4Ti5O12) lithium titanate oxide hydrogen titanate nanowire hybrid super capacitor

Low-temperature crystalline lead-free piezoelectric thin films grown on 2D perovskite nanosheet for flexible electronic device applications

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Nano Research 2019年第10期12卷 2559-2567页

作者： jong-hyun kim Sang Hyo Kweon Sahn Nahm KU-KIST Graduate School of Converging Science and Technology Korea University145 Anam-roSeongbuk-guSeoul 02841Republic of Korea Department of Material Science and Engineering Korea University145 Anam-roSeongbuk-guSeoul 02841Republic of Korea Department of Mechanical Engineering Kobe University1-1 Rokkodai-choNadaKobe 657-8501Japan

A monolayer of Sr2Nb3Oio(SNO)is deposited on the Pt/Ti/SiCWSi(Pt?Si)or Pt/Ti/polyimide(Pt-Pl)substrate by using the Langmuir-Blodgett method and employed as a seed-layer for the growth of a crystalline(Nai_xKx)NbO3(NKN)film at 350℃.The crystalline NKN film is grown along the[001]direction on the SNO/Pt-Si(or SNO/Pt-PI)*** to the presence of oxygen vacancies in the SNO seed-layer,the NKN film exhibits low ferroelectric properties and large leakage *** ameliorate these properties,the SNO/Pt-Si substrate is annealed in a 50 Torr oxygen atmosphere at 300℃,which removes the oxygen ***,the NKN film deposited on this substrate exhibits promising electrical properties,namely a dielectric constant of 278,dissipation factor of 1.7%,a piezoelectric 8nstant of 175 pm`V^-1,and a leakage current density of 6.47 x 10^-7 A cm^-2 at-0.2 MV *** electrical properties are obtained from the NKN film grown on the flexible SNO/Pt-PI substrate at 350°***,the NKN films grown on the SNO seed-layer at 350°C can be applied to electronic devices with flexible polymer substrates.

关键词： lead-free piezoelectric thin films low-temperature-deposition process two-dimensional(2D)nanosheet seed-layers polymer substrates

Chemical and mechanical properties of stainless, environment-friendly, and nonflammable Mg alloys (SEN alloys): A review

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Journal of Magnesium and Alloys 2024年第3期12卷 841-872页

作者： jong Un Lee hyun Ji kim Sang-Cheol Jin Ye Jin kim Young Min kim Bong Sun You Jun Ho Bae Sung Hyuk Park Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea Department of Materials Science and Metallurgical Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Missile Research Institute Agency for Defense DevelopmentDaejeon 34060Republic of Korea

This review article provides overall understanding of stainless,environment-friendly,and nonflammable Mg alloys(SEN alloys)recently developed at the Korea Institute of Materials *** alloys are produced by adding small amounts of Ca and Y(each<1 wt%)into commercial Mg–Al based alloys,resulting in exceptional ignition and corrosion resistances and impressive mechanical *** main advantages of SEN alloys are as follows.(1)A dense multi-oxide layer of SEN alloys comprising MgO,CaO,and Y_(2)O_(3) impedes the outward dispersion of Mg vapor and the inward penetration of O_(2) during oxidation,thereby enhancing the oxidation and ignition resistances.(2)The presence of Ca-and Y-based second-phase particles in SEN alloys can enhance their corrosion resistance because Ca-containing particles prevent the spread of corrosion,and the replacement of Al-containing particles with less noble ones containing Y(e.g.,Al–Mn–Y or Al–Y particles)retards corrosion.(3)The addition of minor amounts of Ca and Y renders excellent mechanical properties due to improved strengthening *** enhanced properties are attributed to more pronounced dynamic recrystallization and grain refining behaviors caused by the second-phase particles during extrusion.(4)Despite the presence of various types of second-phase particles,the fatigue properties of SEN9 alloys are similar to those of commercial AZ91 alloys.(5)Simultaneous introduction of Ca and Y suppresses the formation of Mg17Al12 discontinuous precipitates during aging,leading to the enhanced elongation of aged SEN alloys.(6)Adding mischmetal into the SEN9 alloy leads to a six-fold enhancement in ***,the studies conducted on SEN alloys demonstrate their excellent ignition and corrosion resistances and mechanical properties,which broaden the industrial applications of Mg alloys by addressing their inherent weaknesses.

关键词： SEN magnesium alloy Corrosion resistance Ignition resistance Mechanical properties Extrudability.

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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

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Targeting the RAS/RAF/MAPK pathway for cancer therapy: from mechanism to clinical studies

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Signal Transduction and Targeted Therapy 2024年第1期9卷 173-210页

作者： Md Entaz Bahar hyun Joon kim Deok Ryong kim Department of Biochemistry and Convergence Medical Sciences and Institute of Medical Science Gyeongsang National UniversityCollege of MedicineJinjuSouth Korea Department of Anatomy and Convergence Medical Sciences and Institute of Medical Science Gyeongsang National UniversityCollege of MedicineJinjuSouth Korea

Metastatic dissemination of solid tumors,a leading cause of cancer-related mortality,underscores the urgent need for enhanced insights into the molecular and cellular mechanisms underlying metastasis,chemoresistance,and the mechanistic backgrounds of individuals whose cancers are prone to *** most prevalent signaling cascade governed by multi-kinase inhibitors is the mitogen-activated protein kinase(MAPK)pathway,encompassing the RAS–RAF–MAPK kinase(MEK)–extracellular signal-related kinase(ERK)*** kinase is a primary mediator of the MAPK pathway,responsible for the sequential activation of downstream targets,such as MEK and the transcription factor ERK,which control numerous cellular and physiological processes,including organism development,cell cycle control,cell proliferation and differentiation,cell survival,and *** in this signaling cascade are associated with diseases such as *** inhibitors(RAFi)combined with MEK blockers represent an FDAapproved therapeutic strategy for numerous RAF-mutant cancers,including melanoma,non-small cell lung carcinoma,and thyroid ***,the development of therapy resistance by cancer cells remains an important ***,an intracellular lysosome-dependent catabolic recycling process,plays a critical role in the development of RAFi resistance in ***,targeting RAF and autophagy could be novel treatment strategies for RAF-mutant *** this review,we delve deeper into the mechanistic insights surrounding RAF kinase signaling in tumorigenesis and ***,we explore and discuss the ongoing development of next-generation RAF inhibitors with enhanced therapeutic ***,this review sheds light on the functional interplay between RAF-targeted therapies and autophagy in cancer.

关键词： RAF insight mechanism

Realizing High Thermoelectric Performance in n-Type Se-Free Bi2Te3 Materials by Spontaneous Incorporation of FeTe2 Nanoinclusions

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Energy & Environmental Materials 2024年第4期7卷 344-354页

作者： Jamil Ur Rahman Woo hyun Nam Yong-Jae Jung jong Ho Won jong-Min Oh Nguyen Van Du Gul Rahman Víctor M.García-Suárez Ran He Kornelius Nielsch Jung Young Cho Won-Seon Seo jong Wook Roh Sang-il kim Soonil Lee Kyu Hyoung Lee hyun Sik kim Weon Ho Shin Leibniz Institute for Solid State and Materials Research Advanced Materials Convergence R&D Division Korea Institute of Ceramic Engineering & Technology Department of Electronic Materials Engineering Kwangwoon University Department of Energy Engineering Dankook University Faculty of Fundamental Science Phenikaa University Department of Physics Quaid-i-Azam University Departamento de Física Universidad de Oviedo Nanomaterials and Nanotechnology Research Center-CINN Department of Materials Science and Engineering Yonsei University School of Nano & Materials Science and Engineering Kyungpook National University Department of Materials Science and Engineering University of Seoul School of Materials Science and Engineering Changwon National University

Bi2Te3-based materials have drawn much attention from the thermoelectric community due to their excellent thermoelectric performance near room ***,the stability of existing n-type Bi2（Te,Se）3materials is still low due to the evaporation energy of Se (37.70 kJ mol-1) being much lower than that of Te (52.55 kJ mol-1).The evaporated Se from the material causes problems in interconnects of the module while degrading the efficiency.

关键词： Bi2Te3 energy harvesting FeTe2 nanoinclusion n-type materials thermoelectric

Recent trends in the epidemiology and clinical outcomes of inflammatory bowel disease in South Korea,2010-2018

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World Journal of Gastroenterology 2024年第9期30卷 1154-1163页

作者： Seulji kim hyun Jung Lee Seung Woo Lee Sanghyun Park Seong-Joon Koh jong Pil Im Byeong Gwan kim Kyung-Do Han Joo Sung kim Department of Internal Medicine Korea Institute of Radiological and Medical SciencesSeoul 01812South Korea Department of Internal Medicine and Liver Research Institute Seoul National University College of MedicineSeoul 03080South Korea Department of Statistics and Actuarial Science Soongsil UniversitySeoul 06978South Korea

BACKGROUND Inflammatory bowel disease(IBD)was previously regarded as a Western disease;however,its incidence is increasing in the *** epidemiology of IBD in Asia differs significantly from the patterns in the *** To comprehensively investigate the epidemiology of IBD in South Korea,inclu-ding its incidence,prevalence,medication trends,and *** We analyzed claims data from the Health Insurance Review and Assessment Service and Rare and Intractable Diseases(RIDs),operated by the National Health Insurance Service of South *** with IBD were identified based on the International Classification of Diseases,Tenth Revision,and RID diagnostic codes for Crohn’s disease(CD)and ulcerative colitis(UC)from 2010 to *** In total,14498 and 31409 patients were newly diagnosed with CD and UC,respectively,between 2010 and *** annual average incidence of CD was 3.11 cases per 105 person-years,and that of UC was 6.74 cases per 10^(5) *** 2014,the incidence rate of CD has been stable,while that of UC has steadily increased,shifting the peak age group from 50-year-olds in 2010 to 20-year-olds in *** CD and UC prevalence increased consistently over the study period;the use of 5-aminosali-cylates and corticosteroids gradually decreased,while that of immunomodulators and biologics steadily increased in both CD and *** clinical outcomes of IBD,such as hospitalization and surgery,decreased during the study *** The CD incidence has been stable since 2014,but that of UC has increased with a shift to a younger age at peak incidence between 2010 and *** clinical outcomes improved over time,with increased use of immunomodu-lators and biologics.

关键词： Inflammatory bowel disease Crohn’s disease Ulcerative colitis Incidence Prevalence

Submicron Ag-coated Cu particles as filler in sintering paste: Suppression of Ag dewetting and improvement of sinterability by surface modification using stearic acid

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Transactions of Nonferrous Metals Society of China 2024年

作者： Yeongjung kim Yong-Sung Eom Kwang-Seong Choi jong-hyun Lee Department of Materials Science and Engineering， Seoul National University of Science and Technology， 232 Gongneung-ro Low-Carbon Integration Tech， Creative Research Section， ETRI， 218 Gajeong-ro Materials Research Institute for Future Convergence， Seoul National University of Science and Technology， 232 Gongneung-ro

Four types of submicron Ag-coated Cu particles with different Ag contents were prepared as sintering paste fillers， and the Ag contents of the particles were measured to be 10， 20， 30， and 40 wt%. Four types of particles （in order of increasing Ag content: A10， A20， A30， and A40） were surface-modified with stearic acid， to suppress the Ag shell dewetting and improve sinterability. The surface-modified particles were mixed with a polyol-based solvent to fabricate a resin-free paste. Subsequently， the pastes were screen-printed onto a slide glass and sintered at 250 ℃ in a nitrogen atmosphere for 1–10 min to form an electrode. The electrical resistivity of the sintered film as a function of sintering time was measured using a four-point probe. All the four surface-modified Cu@Ag particles with different Ag contents exhibited decreased electrical resistivity. Particularly， the largest difference in values after and before the surface modification was observed for A40 with the highest Ag content; the electrical resistivities of the initial and surface-modified particles were 1.51×10-4and 6.67×10-5Ω·cm， respectively， after sintering for 10 min. The findings of this study confirmed that the surface modification using stearic acid effectively suppressed the dewetting of the Ag shell and improved the sinterability of the submicron Cu@Ag particles.

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Depolarization mitigated in ferroelectric Hf_(0.5)Zr_(0.5)O_(2)ultrathin films(<5 nm)on Si substrate by interface engineering

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Journal of Advanced Ceramics 2024年第3期13卷 282-292页

作者： Se hyun kim Younghwan Lee Dong hyun Lee Geun Hyeong Park hyun Woo Jeong Kun Yang Yong Hyeon Cho Young Yong kim Min Hyuk Park Department of Materials Science and Engineering College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Research Institute of Advanced Materials College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Inter-university Semiconductor Research Center College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Pohang Accelerator Laboratory Pohang University of Science&TechnologyPohang 790784Republic of Korea

(Hf,Zr)O_(2)offers considerable potential for next-generation semiconductor devices owing to its nonvolatile spontaneous polarization at the ***,scaling this material to sub-5 nm thickness poses several challenges,including the formation of an interfacial layer and high trap *** particular,a low-k SiO_(2)interfacial layer is naturally formed when(Hf,Zr)O_(2)films are directly grown on a Si substrate,leading to high depolarization fields and rapid reduction of the remanent *** address these issues,we conducted a study to significantly improve ferroelectricity and switching endurance of(Hf,Zr)O_(2)films with sub-5 nm thicknesses by inserting a TiO_(2)interfacial *** deposition of a Ti film prior to Hf_(0.5)Zr_(0.5)O_(2)film deposition resulted in a high-k TiO_(2)interfacial layer and prevented the direct contact of Hf_(0.5)Zr_(0.5)O_(2)with *** findings show that the high-k TiO_(2)interfacial layer can reduce the SiO_(2)/Si interface trap density and the depolarization field,resulting in a switchable polarization of 60.2μC/cm^(2)for a 5 nm thick Hf_(0.5)Zr_(0.5)O_(2)***,we propose that inserting a high-k TiO_(2)interfacial layer between the Hf_(0.5)Zr_(0.5)O_(2)film and the Si substrate may offer a promising solution to enhancing the ferroelectricity and reliability of(Hf,Zr)O_(2)grown on the Si substrate and can pave the way for next-generation semiconductor devices with improved performance.

关键词： ferroelectric charge trapping hafnia depolarization