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Effect of Cu seed on the synthesis and characterization of FeCo alloy nano-particles by using polyol method

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Science China(Technological Sciences) 2009年第1期52卷 19-22页

作者： Uk Rae CHO young min lee Shalendra KUMAR Chan Gyu lee Bon Heun KOO School of Nano-Advanced Materials Engineering Changwon National University Changwon

Fine metal particles with uniform shape, narrow size distribution and high purity are increasingly needed for specific uses in high tech industrial application. We report the direct chemical synthesis of FeCo alloy particles using the mixture of FeCl2·4H2O, Co (Ac)2·4H2O (Ac: acetate) and NaOH in ethylene glycol, and then obtained FeCo alloy particles better dispersed by adding the polyvinylpyrrolidone (PVP) and also the size could be controlled by adding copper. The prepared nano-particles were characterized using FESEM, XRD and VSM. The mean diameter of these particles was varied in the range of sub- mi- crometer to nanometer with metal-ion concentration. FeCo particles showed the typical soft magnetic properties.

关键词： polyol method FeCo alloy nanoparticle Cu seed soft magnetic

Novel fabrication techniques for ultra-thin silicon based flexible electronics

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International Journal of Extreme Manufacturing 2024年第4期6卷 116-149页

作者： Ju young lee Jeong Eun Ju Chanwoo lee Sang min Won Ki Jun Yu School of Electrical and Electronic Engineering Yonsei University50 Yonsei-roSeodaemunguSeoul 03722Republic of Korea Department of Electrical and Computer Engineering Sungkyunkwan UniversitySuwon 16419Republic of Korea YU-Korea Institute of Science and Technology(KIST)Institute Yonsei University50Yonsei-roSeodaemun-guSeoul 03722Republic of Korea

Flexible electronics offer a multitude of advantages,such as flexibility,lightweight property,portability,and high *** unique properties allow for seamless applications to curved and soft surfaces,leading to extensive utilization across a wide range of fields in consumer *** applications,for example,span integrated circuits,solar cells,batteries,wearable devices,bio-implants,soft robotics,and biomimetic ***,flexible electronic devices have been developed using a variety of materials such as organic,carbon-based,and inorganic semiconducting ***(Si)owing to its mature fabrication process,excellent electrical,optical,thermal properties,and cost efficiency,remains a compelling material choice for flexible ***,the research on ultra-thin Si in the context of flexible electronics is studied rigorously *** thinning of Si is crucially important for flexible electronics as it reduces its bending stiffness and the resultant bending strain,thereby enhancing flexibility while preserving its exceptional *** review provides a comprehensive overview of the recent efforts in the fabrication techniques for forming ultra-thin Si using top-down and bottom-up approaches and explores their utilization in flexible electronics and their applications.

关键词： flexible electronics silicon fabrication technique top-down approach bottom-up approach

Effect of characteristics and distribution of Mg_(17)Al_(12)precipitates on tensile and bending properties of high-Al-containing Mg alloys

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Journal of Magnesium and Alloys 2024年第2期12卷 779-793页

作者： Sumi Jo Gyo Myeong lee Jong Un lee young min Kim Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Department of Magnesium Korea Institute of Materials ScienceChangwon 51508Republic of Korea

This study investigates the effect of characteristics and distribution of Mg_(17)Al_(12)precipitates on the uniaxial tensile and three-point bending properties of extruded Mg alloys containing high Al *** extruded Mg–9Al–1Zn–0.3Mn(AZ91)alloy contains lamellar-structured Mg_(17)Al_(12)discontinuous precipitates along the grain boundaries,which are formed via static precipitation during natural air *** extruded Mg–11Al–1Zn–0.3Mn(AZ111)alloy contains spherical Mg_(17)Al_(12)precipitates at the grain boundaries and inside the grains,which are formed via dynamic precipitation during *** to inhomogeneous distribution of precipitates,the AZ111 alloy consists of two different precipitate regions:precipitate-rich region with numerous precipitates and finer grains and precipitate-scarce region with a few precipitates and coarser *** AZ111 alloy exhibits a higher tensile strength than the AZ91 alloy because its smaller grain size and more abundant precipitates result in stronger grain-boundary hardening and precipitation hardening effects,***,the tensile elongation of the AZ111 alloy is lower than that of the AZ91 alloy because the weak cohesion between the dynamic precipitates and the matrix facilitates the crack initiation and *** bending,a macrocrack initiates on the outer surface of bending specimen in both *** AZ111 alloy exhibits higher bending yield strength and lower failure bending strain than the AZ91 *** bending specimens of the AZ91 alloy have similar bending formability,whereas those of the AZ111 alloy exhibit considerable differences in bending formability and crack propagation behavior,depending on the distribution and number density of precipitates in the *** bending specimens of the AZ111 alloy,it is found that the failure bending strain(ε_(f,bending))is inversely proportional to the area fraction of precipitates in the outer zone of bending specimen(A_(ppt)),with a relation

关键词： Mg–Al alloy Extrusion Bending Precipitation Microstructure

Multiphase cooperation for multilevel strain accommodation in a single-crystalline BiFeO3 thin film

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Chinese Physics B 2024年第9期33卷 57-66页

作者： Wooseon Choi Bumsu Park Jaejin Hwang Gyeongtak Han Sang-Hyeok Yang Hyeon Jun lee Sung Su lee Ji young Jo Albina Y.Borisevich Hu young Jeong Sang Ho Oh Jaekwang lee young-min Kim Department of Energy Science Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Samsung Electronics Hwaseong 18448Republic of Korea Department of Physics Pusan National UniversityBusan 46241Republic of Korea LG Energy Solution Daejeon 34122Republic of Korea Department of Materials Science and Engineering Kangwon National UniversityRepublic of Korea School of Materials Science and Engineering Gwangju Institute of Science and Technology(GIST)Gwangju 61005Republic of Korea Center for Nanophase Materials Sciences Oak Ridge National LaboratoryTN 37831USA Graduate School of Semiconductor Materials and Devices Engineering Ulsan National Institute of Science and Technology(UNIST)Ulsan 44919Republic of Korea Department of Energy Engineering KENTECH Institute for Energy Materials and DevicesKorea Institute of Energy Technology(KENTECH)Naju 58330Republic of Korea

The functionalities and diverse metastable phases of multiferroic BiFeO3(BFO)thin films depend on the misfit *** mixed phase-induced strain relaxation in multiphase BFO thin films is well known,it is unclear whether a singlecrystalline BFO thin film can accommodate misfit strain without the involvement of its ***,understanding the strain relaxation behavior is key to elucidating the lattice strain–property *** this study,a correlative strain analysis based on dark-field inline electron holography(DIH)and quantitative scanning transmission electron microscopy(STEM)was performed to reveal the structural mechanism for strain accommodation of a single-crystalline BFO thin *** nanoscale DIH strain analysis results indicated a random combination of multiple strain states that acted as a primary strain relief,forming irregularly strained *** STEM-based bond length measurement of the corresponding strained nanodomains revealed a unique strain accommodation behavior achieved by a statistical combination of multiple modes of distorted structures on the unit-cell *** globally integrated strain for each nanodomain was estimated to be close to􀀀1.5%,irrespective of the nanoscale strain states,which was consistent with the fully strained BFO film on the SrTiO3 *** functional theory calculations suggested that strain accommodation by the combination of metastable phases was energetically favored compared to single-phase-mediated *** discovery allows a comprehensive understanding of strain accommodation behavior in ferroelectric oxide films,such as BFO,with various low-symmetry polymorphs.

关键词： BiFeO_(3) scanning transmission electron microscopy electron holography multiferroic material strain mapping

A Solvent-Free Covalent Organic Framework Single-Ion Conductor Based on Ion-Dipole Interaction for All-Solid-State Lithium Organic Batteries

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Nano-Micro Letters 2024年第12期16卷 189-200页

作者： Zhongping Li Kyeong-Seok Oh Jeong-min Seo Wenliang Qin Soohyoung lee Lipeng Zhai Changqing Li Jong-Beom Baek Sang-young lee Department of Chemical and Biomolecular Engineering Yonsei University50 Yonsei-RoSeodaemun-GuSeoul 03722Republic of Korea School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology(UNIST)50 UNIST-GilEonyang-EupUlju-GunUlsan 44919Republic of Korea Henan Key Laboratory of Functional Salt Materials Center for Advanced Materials ResearchZhongyuan University of TechnologyZhengzhou 450007People’s Republic of China Department of Battery Conflation Engineering Yonsei University50Yonsei-RoSeodaemun-GuSeoul 03772Republic of Korea Department of Battery Engineering Yonsei University50Yonsei-RoSeodaemun-GuSeoul 03772Republic of Korea

Single-ion conductors based on covalent organic frameworks(COFs)have garnered attention as a potential alternative to currently prevalent inorganic ion conductors owing to their structural uniqueness and chemical ***,the sluggish Li+conduction has hindered their practical ***,we present a class of solvent-free COF single-ion conductors(Li-COF@P)based on weak ion-dipole interaction as opposed to traditional strong ion-ion *** ion(Li+from the COF)-dipole(oxygen from poly(ethylene glycol)diacrylate embedded in the COF pores)interaction in the Li-COF@P promotes ion dissociation and Li+migration via directional ionic *** by this single-ion transport behavior,the Li-COF@P enables reversible Li plating/stripping on Li-metal electrodes and stable cycling performance(88.3%after 2000 cycles)in organic batteries(Li metal anode||5,5’-dimethyl-2,2’-bis-p-benzoquinone(Me2BBQ)cathode)under ambient operating conditions,highlighting the electrochemical viability of the Li-COF@P for all-solid-state organic batteries.

关键词： Solid organic single-ion conductors Solvent-free covalent organic frameworks All-solid-state Li organic batteries Ion-dipole interaction Pore functionalization

Transparent high-performance piezoceramics through pressureless sintering

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Journal of Advanced Ceramics 2024年第5期13卷 561-567页

作者： Hye-Lim Yu Woo-Seok Kang Ju-Hyeon lee Temesgen Tadeyos Zate young-Jin lee Bo-Kun Koo Dong-Jin Shin min-Soo Kim Soon-Jong Jeong young Ghyu Ahn Wook Jo Department of Material Science and Engineering Ulsan National Institute of Science and TechnologyUlsan 44919Republic of Korea Energy Conversion Research Center Korea Electrotechnology Research InstituteChangwon 51543Republic of Korea MLCC Development Team Component Biz.UnitSamsung Electro-Mechanics Co.Ltd.Suwon 16674Republic of Korea

Piezoelectricity offers an electromechanical coupling that is widely utilized in transducer *** has been a consistent demand for transparent piezoelectric materials for optoelectrical ***,despite the inherent tradeoff between the transparency and the piezoelectricity,numerous strategies have been explored to develop the transparent piezoelectric ***,the most transparent piezoelectric materials developed to date is either a single crystal or materials that achieve transparency via hot-press sintering,limiting its industrial ***,we introduce a novel piezoelectric material that ensures transparency through co-doping and pressureless sintering of polycrystalline *** this study,we employed a compositional optimization approach to enhance the synergistic effect between the transparency and the piezoelectric properties of 0.71Pb(Mg_(1/3)Nb_(2/3))O_(3)–0.29PbTiO_(3)(PMN–0.29PT)*** utilizing the tape casting process for mass production and large-area manufacturing,our Pb_(0.913)La_(0.0145)Sm_(0.0145)(Mg_(1/3)Nb_(2/3))_(0.71)Ti_(0.29)O_(3)(TP2.9)ceramics exhibited over 60%transparency and large piezoelectric coefficient(d33)of 1104 pC/*** material holds considerable promise for a wide range of industrial applications in both the optical and electronic domains.

关键词： piezoelectric ceramics transparency pressureless sintering co-doping tape casting

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

Long-term outcome of stem cell transplantation with and without anti-tumor necrotic factor therapy in perianal fistula with Crohn’s disease

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World Journal of Stem Cells 2024年第3期16卷 257-266页

作者： min young Park Yong Sik Yoon Jae Ha Park Jong Lyul lee Chang Sik Yu Division of Colon and Rectal Surgery Department of SurgeryYonsei University College of MedicineSeoul 03722South Korea Division of Colon and Rectal Surgery Department of SurgeryUniversity of Ulsan College of MedicineAsan Medical CenterSeoul 05505South Korea

BACKGROUND Stem cell transplantation is a promising therapeutic option for curing perianal fistula in Crohn’s disease(CD).Anti-tumor necrotic factor(TNF)therapy combined with drainage procedure is effective as ***,previous studies are limited to proving whether the combination treatment of biologics and stem cell transplantation improves the effect of fistula *** This study aimed to evaluate the long-term outcomes of stem cell transplantation and compare Crohn’s perianal fistula(CPF)closure rates after stem cell transplantation with and without anti-TNF therapy,and to identify the factors affecting CPF closure and *** The patients with CD who underwent stem cell transplantation for treating perianal fistula in our institution between Jun 2014 and December 2022 were *** data were compared according to anti-TNF therapy and CPF *** A total of 65 patients were *** median age of females was 26 years(range:21-31)and that of males was 29(44.6%).The mean follow-up duration was 65.88±32.65 months,and complete closure was observed in 50(76.9%)*** closure rates were similar after stem cell transplantation with and without anti-TNF therapy(66.7%vs 81.6%at 3 year,P=0.098).The patients with fistula closure had short fistulous tract and infrequent proctitis and anorectal stricture(P=0.027,0.002,and 0.008,respectively).Clinical factors such as complexity,number of fistulas,presence of concurrent abscess,and medication were not significant for *** cumulative 1-,2-,and 3-year closure rates were 66.2%,73.8%,and 75.4%,*** Anti-TNF therapy does not increase CPF closure rates in patients with stem cell ***,both refractory and non-refractory CPF have similar closure rates after additional anti-TNF *** tract length,proctitis,and anal stricture are risk factors for non-closure in patients with CPF after stem cell transplantation.

关键词： Crohn’s disease Anus Fistula Stem cell transplantation Tumor necrosis factor-alpha inhibitors Infliximab

Value of glucose transport protein 1 expression in detecting lymph node metastasis in patients with colorectal cancer

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World Journal of Clinical Cases 2024年第5期12卷 931-941页

作者： Hongsik Kim Song-Yi Choi Tae-young Heo Kyeong-Rok Kim Jisun lee min young Yoo Taek-Gu lee Joung-Ho Han Department of Internal Medicine Chungbuk National University HospitalCheongju 28644South Korea Department of Pathology Chungnam National University College of MedicineDaejeon 35015South Korea Information and Statistics Chungbuk National UniversityCheongju 28644South Korea Department of Radiology College of MedicineChungbuk National UniversityChungbuk National University HospitalCheongju-si 28644South Korea Department of Nuclear Medicine School of MedicineInha UniversityIncheon 22332South Korea Department of Surgery Chungbuk National UniversityCollege of MedicineCheongju-si 28644South Korea Department of Internal Medicen Chungbuk National UniversityCollege of medicineCheongju-si 28644South Korea

BACKGROUND There are limited data on the use of glucose transport protein 1(GLUT-1)expre-ssion as a biomarker for predicting lymph node metastasis in patients with colorectal ***-1 and GLUT-3,hexokinase(HK)-II,and hypoxia-induced factor(HIF)-1 expressions may be useful biomarkers for detecting primary tumors and lymph node metastasis when combined with fluorodeoxyglucose(FDG)uptake on positron emission tomography/computed tomography(PET/CT).AIM To evaluate GLUT-1,GLUT-3,HK-II,and HIF-1 expressions as biomarkers for detecting primary tumors and lymph node metastasis with 18F-FDG-PET/*** This retrospective study included 169 patients with colorectal cancer who underwent colectomy and preoperative 18F-FDG-PET/CT at Chungbuk National University Hospital between January 2009 and May *** tissue cores from the central and peripheral areas of the tumors were obtained and were examined by a dedicated pathologist,and the expressions of GLUT-1,GLUT-3,HK-II,and HIF-1 were determined using immunohisto-chemical *** analyzed the correlations among their expressions,various clinicopathological factors,and the maximum standardized uptake value(SUVmax)of PET/*** GLUT-1 was found at the center or periphery of the tumors in 109(64.5%)of the 169 ***-1 positivity was significantly correlated with the SUVmax of the primary tumor and lymph nodes,regardless of the biopsy site(tumor center,P<0.001 and P=0.012;tumor periphery,P=0.030 and P=0.010,respectively).GLUT-1 positivity and negativity were associated with higher and lower sensitivities of PET/CT,respectively,for the detection of lymph node metastasis,regardless of the biopsy ***3,HK-II,and HIF-1 expressions were not significantly correlated with the SUVmax of the primary tumor and lymph *** GLUT-1 expression was significantly correlated with the SUVmax of 18F-FDG-PET/CT for primary tumors and lymph *** should consider GLUT-1 expression in preoperative endoscop

关键词： 18F-FDG-PET-CT Biomarker Colorectal neoplasms Glucose transporter type 1 Lymph node