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Carbon Energy 2023年第10期5卷 25-39页

作者： Madagonda MVadiyar Ji‐Young Kim jee‐hwan bae Kyung‐Wan Nam Department of Energy and Materials Engineering Dongguk UniversitySeoulSouth Korea Advanced Analysis&Data Center Korea Institute of Science and Technology(KIST)SeoulSouth Korea Advanced Energy and Electronic Materials Research Center Dongguk UniversitySeoulSouth Korea

Carbon super-heterostructures with high nitrogen contents from the covalent hybrid precursors of covalent triazine frameworks(CTFs)and zeolitic imidazolic frameworks(ZIFs)are scarcely explored because of CTF's ordered structure and toxic superacid that dissolves or destabilizes the metal *** solve this problem,herein,we report a straightforward two-step pathway for the covalent hybridization of disordered CTF(d–CTF)–ZIF composites via preincorporation of an imidazole(IM)linker into ordered CTFs,followed by the imidazole-site-specific covalent growth of *** carbonization of these synthesized d–CTF−IM−ZIF hybrids results in unique hollow carbon super-heterostructures with ultrahigh nitrogen content(>18.6%),high specific surface area(1663m^(2)g^(−1)),and beneficial trace metal(Co/Zn NPs)contents for promoting the redox *** proof of concept,the obtained carbon super-heterostructure(Co–Zn–NC_(SNH)–800)is used as a positive electrode in an asymmetric supercapacitor,demonstrating a remarkable energy density of 61Wh kg^(−1)and extraordinary cyclic stability of 97%retention after 30,000 cycles at the cell *** presynthetic modifications of CTF and their covalent hybridization with ZIF crystals pave the way toward new design strategies for synthesizing functional porous carbon materials for promising energy applications.

关键词： asymmetric supercapacitor defective covalent triazine frameworks hollow carbon superheterostructures linker defect

Effects of Cr doping on structural and electrochemical properties of Li_(4)Ti_(5)O_(12) nanostructure for sodium-ion battery anode

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Journal of Energy Chemistry 2021年第8期30卷 465-472,I0010页

作者： Sang Hyuk Gong Ji Hyeon Lee Dong Won Chun jee-hwan bae Sung-Chul Kim Seungho Yu Sahn Nahm Hyung-Seok Kim Center for Energy Storage Research Korea Institute of Science and Technology5Hwarang-ro 14-gilSeongbuk-gu02792 SeoulRepublic of Korea Department of Materials Science and Engineering Korea University145Anam-roSeongbuk-gu02841 SeoulRepublic of Korea Department of Chemical and Biological Engineering Korea University145Anam-roSeongbuk-gu02841 SeoulRepublic of Korea Advanced Analysis Center Korea Institute of Science and Technology5Hwarang-ro 14-gilSeongbuk-gu02792 SeoulRepublic of Korea

Sodium-ion batteries are considered as promising alternatives to lithium-ion batteries,owing to their low cost and abundant raw *** the several candidate materials for the anode,spinel-type Li_(4)Ti_(5)O_(12)has potential owing to its superior safety originating from an appropriate operating voltage and the reversible Na^(+)intercalation ***,a low diffusion coefficient for Na^(+)and the insulating nature of LTO remains challenging for practical sodium-ion battery ***,we present a strategy for integrating physical and chemical approaches to achieve superior electrochemical properties in *** demonstrate that carefully controlling the amount of Cr doping is crucial to enhance the electrochemical properties of nanostructured *** Cr doped LTO shows a superior reversible capacity of 110 m Ah g^(-1) after 400 cycles at 1 C,with a three-fold higher capacity(75 m Ah g^(-1))at 10 C compared with undoped LTO *** suggests that appropriately Cr doped nanostructured LTO is a promising anode material for sodium-ion batteries.

关键词： Sodium-ion batteries Spinel type Li_(4)Ti_(5)O_(12) Anode materials Nanostructuring Cr-doping

Effect of tellurium on the microstructure and mechanical properties of Fe-14Cr oxide-dispersion-strengthened steels produced by additive manufacturing

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Journal of Materials Science & Technology 2021年第36期95卷 114-126页

作者： Barton Mensah Arkhurst jee hwan bae Min Young Na Hye Jung Chang Hyun Gil Kim Il Hyun Kim Ho Jin Ryu Jeoung Han Kim School of Materials Science and Engineering University of New South Wales SydneyNSW 2052Australia Advanced Analysis Center Korea Institute of Science and Technology SeoulSeongbuk-guRepublic of Korea LWR Fuel Technology Division Korea Atomic Energy Research InstituteDaejeonYuseong-guRepublic of Korea Department of Nuclear and Quantum Engineering KAISTDaejeonYuseong-guRepublic of Korea Department of Materials Science&Engineering Hanbat National UniversityRepublic of Korea

Conventionally,Te has primarily been used to improve the machinability of steel and its *** this work,Te was used to refine the grains of an oxide-dispersion-strengthened(ODS)steel produced by additive manufacturing(AM)with fixed processing *** of Te to the raw powder produced an ODS steel with a fine-grained microstructure,in contrast to the ODS steel manufactured without ***,the addition of Te resulted in superior yield strength and ultimate tensile strength,which was attributed to the combined effects of grain refinement and the finer nanoparticles(NPs)composed of Terich composite NPs and Cr-rich *** the first time,the AM technique was used to obtain grain and nanoparticle sizes of~3.4μm and 6 nm,respectively,from the Te-added ODS steel.

关键词： Additive manufacturing Directed energy deposition Oxide-dispersion-strengthened steel Nanoparticle Tellurium

Electron beam deposition and characterization of thin film Ti-Ni for shape memory applications

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Rare Metals 2006年第z2期25卷 237-242页

作者： NOH Hae-Yong jee Kwang-Koo LEE Kyu-hwan LEE Young-Kook Department of Metallurgical System Yonsei University Seoul 120-749 KoreaAdvanced Materials Research Center Division of Materials Korea Institute of Science and Technology Cheongryang Seoul 130-650 Korea Advanced Materials Research Center Division of Materials Korea Institute of Science and Technology Cheongryang Seoul 130-650 Korea Department of Metallurgical System Yonsei University Seoul 120-749 Korea

Thin film of Ti-Ni alloy has a potential to perform the microactuation functions required in the microelectromechanical system (MEMS). It is essential, however, to have good uniformity in both chemical composition and thickness to realize its full potential as an active component of MEMS devices. Electron beam evaporation technique was employed in this study to fabricate the thin films of Ti-Ni alloy on different substrates. The targets used for the evaporation were first prepared by electron beam melting. The uniformity of composition and microstructure of the thin films were characterized by electron probe microanalysis (EPMA), Auger electron spectroscopy (AES), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM). The mechanical property of the thin films was evaluated by the nano-indentation test. The martensitic transformation temperature was measured by differential scanning calorimetry (DSC). It is confirmed that the chemical composition of deposited thin films is identical to that of the target materials. Furthermore, results from depth profiling of the chemical composition variation reveal that the electron beam evaporation process yields better compositional homogeneity than other conventional methods such as sputtering and thermal evaporation. Microstructural observation by TEM shows that nanometer size precipitates are preferentially distributed along the grain boundaries of a few micron size grains. The hardness and elastic modulus of thin films decreases with an increase in Ti contents.

关键词： electron beam evaporation TiNi SMA thin film martensitic transformation reverse martensitic transformation

Obesity and novel management of inflammatory bowel disease

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World Journal of Gastroenterology 2023年第12期29卷 1779-1794页

作者： jee Hyun Kim Chang-Myung Oh Jun hwan Yoo Department of Gastroenterology CHA Bundang Medical CenterCHA University School of MedicineSeongnam 13496South Korea Department of Biomedical Science and Engineering Gwangju Institute of Science and TechnologyGwangju 62465South Korea Institute of Basic Medical Sciences CHA University School of MedicineSeongnam 13496South Korea

Obesity is prevalent within the inflammatory bowel disease(IBD)population,particularly in newly developed *** epidemiological studies have suggested that 15%-40%of IBD patients are obese,and there is a potential role of obesity in the pathogenesis of *** dysfunction of mesenteric fat worsens the inflammatory course of Crohn’s disease and may induce formation of strictures or ***,obesity may affect the disease course or treatment response of *** the increasing data supporting the pathophysiologic and epidemiologic relationship between obesity and IBD,obesity control is being suggested as a novel management for ***,this review aimed to describe the influence of obesity on the outcomes of IBD treatment and to present the current status of pharmacologic or surgical anti-obesity treatments in IBD patients.

关键词： Obesity Inflammatory bowel disease Crohn’s disease Ulcerative colitis

Formation of intermetallic compound at interface between rare earth elements and ferritic-martensitic steel by fuel cladding chemical interaction

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Journal of Rare Earths 2012年第6期30卷 599-603页

作者： Jun hwan Kim Byoung Oon Lee Chan Bock Lee Seung Hyun jee Young Soo Yoon Advanced Fuel Development Division Korea Atomic Energy Research InstituteP.O.Box 105YuseongDaejeon305-600Republic of Korea Department of Mate-rials Science and Engineering Yonsei University134 Sinchon DongSeoul120-749Republic of Korea

The intermetallic compounds formation at interface between rare earth elements and clad material were investigated to demonstrate the effects of rare earth elements on fuel-cladding chemical interaction （FCCI） behavior. Mischmetal （70Ce-30La） and Nd were prepared as rare earth elements. Diffusion couple testing was performed on the rare earth elements and cladding （9Cr2W steel） near the operation temperature of （sodium-cooled fast reactor） SFR fuel. The performance of a diffusion barrier consisting of Zr and V metallic foil against the rare earth elements was also evaluated. Our results showed that Ce and Nd in the rare earth elements and Fe in the clad material interdiffused and reacted to form intermetallic species according to the parabolic rate law, describing the migration of the rare earth element. The diffusion of Fe limited the reaction progress such that the entire process was governed by the cubic rate law. Rare earth materials could be used as a surrogate for high burnup metallic fuels, and the performance of the barrier material was demonstrated to be effective.

关键词： intermetallic compound sodium-cooled fast reactor (SFR) metallic fuel fuel-cladding chemical interaction (FCCI) rare earths Barrier

Effects of ocean acidifi cation driven by elevated CO_2 on larval shell growth and abnormal rates of the venerid clam, Mactra veneriformis

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Chinese Journal of Oceanology and Limnology 2016年第6期34卷 1191-1198页

作者： jee-Hoon KIM Ok hwan YU Eun Jin YANG Sung-Ho KANG Won KIM Eun Jung CHOY Division of Polar Ocean Environment Research Korea Polar Research Institute Korea Institute of Ocean Science and Technology School of Biological Sciences Seoul National University Marine Ecosystem Research Division Korea Institute of Ocean Science and Technology

A bstract The venerid clam(M actra veneriformis Reeve 1854) is one of the main cultured bivalve species in intertidal and shallow subtidal ecosystems along the west coast of Korea. To understand the effects of ocean acidifi cation on the early life stages of Korean clams, we investigated shell growth and abnormality rates and types in the D-shaped, umbonate veliger, and pediveliger stages of the venerid clam M. veneriformis during exposure to elevated seawater pCO_2. In particular, we examined abnormal types of larval shell morphology categorized as shell deformations, shell distortions, and shell fi ssures. Specimens were incubated in seawater equilibrated with bubbled CO_2-enriched air at(400±25)×10^(-6)(ambient control),(800±25)×10^(-6)(high pCO_2), or(1 200±28)×10^(-6)(extremely high pCO_2), the atmospheric CO_2 concentrations predicted for the years 2014, 2084, and 2154(70-year intervals; two human generations), respectively, in the Representative Concentration Pathway(RCP) 8.5 scenario. The mean shell lengths of larvae were signifi cantly decreased in the high and extremely high pCO_2 groups compared with the ambient control groups. Furthermore, under high and extremely high pCO_2 conditions, the cultures exhibited signifi cantly increased abundances of abnormal larvae and increased severity of abnormalities compared with the ambient control. In the umbonate veliger stage of the experimental larvae, the most common abnormalities were shell deformations, distortions, and fi ssures; on the other hand, convex hinges and mantle protuberances were absent. These results suggest that elevated CO_2 exerts an additional burden on the health of M. veneriformis larvae by impairing early development.

关键词： abnormality larval shell growth Mactra veneriformis ocean acidifi cation pCO2

Longitudinal evolution of cortical thickness signature reflecting Lewy body dementia in isolated REM sleep behavior disorder:a prospective cohort study

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Translational Neurodegeneration 2023年第1期12卷 514-528页

作者： Jung hwan Shin Heejung Kim Yu Kyeong Kim Eun Jin Yoon Hyunwoo Nam Beomseok Jeon jee-Young Lee Department of Neurology Seoul Metropolitan Government-Seoul National University Boramae Medical Center and Seoul National University College of MedicineSeoulSouth Korea Department of Nuclear Medicine Seoul Metropolitan Government-Seoul National University Boramae Medical Center and Seoul National University College of MedicineSeoulSouth Korea Institute of Radiation Medicine Medical Research CenterSeoul National UniversitySeoulSouth Korea Department of Neurology Seoul National University Hospital and Seoul National University College of MedicineSeoulSouth Korea

Background The isolated rapid-eye-movement sleep behavior disorder(iRBD)is a prodromal condition of Lewy body disease including Parkinson’s disease and dementia with Lewy bodies(DLB).We aim to investigate the longitudinal evolution of DLB-related cortical thickness signature in a prospective iRBD cohort and evaluate the possible predictive value of the cortical signature index in predicting dementia-first phenoconversion in individuals with *** We enrolled 22 DLB patients,44 healthy controls,and 50 video polysomnography-proven iRBD *** underwent 3-T magnetic resonance imaging(MRI)and clinical/neuropsychological *** characterized DLB-related whole-brain cortical thickness spatial covariance pattern(DLB-pattern)using scaled subprofile model of principal components analysis that best differentiated DLB patients from age-matched *** analyzed clinical and neuropsychological correlates of the DLB-pattern expression scores and the mean values of the whole-brain cortical thickness in DLB and iRBD *** repeated MRI data during the follow-up in our prospective iRBD cohort,we investigated the longitudinal evolution of the cortical thickness signature toward Lewy body ***,we analyzed the potential predictive value of cortical thickness signature as a biomarker of phenoconversion in iRBD *** The DLB-pattern was characterized by thinning of the temporal,orbitofrontal,and insular cortices and relative preservation of the precentral and inferior parietal *** DLB-pattern expression scores correlated with attentional and frontal executive dysfunction(Trail Making Test-A and B:R=−0.55,P=0.024 and R=−0.56,P=0.036,respectively)as well as visuospatial impairment(Rey-figure copy test:R=−0.54,P=0.0047).The longitudinal trajectory of DLB-pattern revealed an increasing pattern above the cut-off in the dementia-first phenoconverters(Pearson’s correlation,R=0.74,P=6.8×10−4)but no significant change in parki

关键词： Rapid eye movement sleep behavior disorder Dementia with Lewy bodies Lewy body disease Cortical thickness Spatial covariance pattern Magnetic resonance imaging

Coherent interface driven super-plastic elongation of brittle intermetallic nano-fibers at room temperature

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Journal of Materials Science & Technology 2022年第20期115卷 97-102页

作者： Eun-Ae Choi Seung Zeon Han Hyung Giun Kim jee Hyuk Ahn Sung hwan Lim Sangshik Kim Nong-Moon hwang Kwangho Kim Jehyun Lee Department of Special Alloy Korea Institute of Materials ScienceChangwon 642-831Korea Gangwon Regional Division Korea Institute of Industrial TechnologyGangneung 210-340Korea Department of Advanced Materials Science&Engineering Kangwon National UniversityChuncheon 200-701Korea Department of Materials Science and Engineering ReCAPTGyeongsang National UniversityChinju 660-701Korea Department of Materials Science and Engineering Seoul National UniversitySeoul 151-744Korea Department of Materials Science and Engineering Pusan National UniversityBusan 46241Korea Department of Materials Science and Engineering Changwon National UniversityChangwon 641-773Korea

The intermetallic compound such as Ni_(2)Si has a brittle ***,monolithic intermetallic compounds have not yet been prepared by mechanical *** mechanical drawing of bulk CuNi_(2)Si alloy at room temperature,we observed more than 400%plastic elongation of hard and brittle Ni_(2)Si intermetallic *** calculation based on the density functional theory reveals that the fully coherent interface induces strain on the intermetallic compound surrounded by the matrix,and lowers the intrinsic stacking fault energy below the level required to break an interatomic *** new interface between the Ni_(2)Si intermetallic and Cu matrix formed by the plastic deformation is as stable as the original coherent interface formed by precipitation,and the activation energy of the newly formed interface to slip is similar to that of the Cu *** of these make plastic deformation of brittle Ni_(2)Si intermetallic possible by slip without failure.

关键词： Ni_(2)Si Intermetallic compound Plastic deformation Precipitation Brittle fiber Interface Density functional theory

Mass forming chronic pancreatitis mimicking pancreatic cystic neoplasm: A case report

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World Journal of Gastroenterology 2018年第2期24卷 297-302页

作者： Keum Nahn jee Department of Radiology Dankook University Hospital

Mass forming chronic pancreatitis is very rare. Diagnosis could be done by the pathologic findings of focal inflammatory fibrosis without evidence of tumor in pancreas. A 34-year-old man presented with right upper abdominal pain for a few weeks and slightly elevated bilirubin level on clinical findings. Radiological findings of multidetector-row computed tomography, magnetic resonance(MR) imaging with MR cholangiopancreatography and endoscopic ultrasonography revealed focal branch pancreatic duct dilatation with surrounding delayed enhancing solid component at uncinate process and head of pancreas, suggesting branch duct type intraductal papillary mucinous neoplasm. Surgery was done and pathology revealed the focal chronic inflammation, fibrosis, and branch duct dilatation. Herein, I would like to report the first case report of mass forming chronic pancreatitis mimicking pancreatic cystic neoplasm.

关键词： Chronic pancreatitis Pseudotumor Computed tomography Magnetic resonance imaging Endoscopic ultrasound