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Texture development and grain boundary phase formation in Ce-and Ce-La-substituted Nd-Fe-B magnets during hot-deformation process

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Journal of Materials Science & Technology 2022年第31期126卷 71-79页

作者： Ga-Yeong kim tae-hoon kim Hee-Ryoung Cha Sang-hyub Lee Dong-Hwan kim Yang-Do kim Jung-Goo Lee Department of Magnetic Materials Korea Institute of Materials ScienceChangwon 51508Republic of Korea Department of Materials Science and Engineering Pusan National UniversityBusan 46241Republic of Korea R&D Center Star Group Ind.Co.Ltd.Daegu 42714Republic of Korea

In this study,the influence of Ce-and Ce-La-substitution for Nd in Nd-Fe-B magnets on their magnetic and microstructural changes in the course of the hot-deformation process was investigated to gain insight into further reducing the Nd content in fine-grained Nd-Fe-B hot-deformed *** found that the[001]texture and microstructure of the RE-rich grain boundary phases,which are the factors that de-termine the remanence and coercivity of hot-deformed magnets,were deteriorated by the Ce-and *** is because the volume fraction of the RE-rich liquid formed in the grain boundaries during the hot-press and hot-deformation decreased due to the Ce-and Ce-La-substitution,thereby in-creasing the friction between the 2:14:1 grains while the c-axes of grains were aligned by grain rotation and decreasing the RE concentration of grain boundary *** particular,the Ce-La-co-substitution further prevented the liquid formation within the grain boundaries of the magnets during hot-press and hot-deformation because the wettability of the RE-rich liquid on the 2:14:1 grains became poor when La was substituted for Nd in the 2:14:1 *** results indicate that there is room for further im-provement in both the remanence and coercivity of the Ce-and Ce-La-substituted magnets by intro-ducing additional liquid into the grain boundaries prior to hot-press and *** applying the Nd-Cu infiltration process to the melt-spun ribbons(intermediate infiltration,I-infiltration),both the remanence and coercivity of the Nd-saving(Nd 0.7 Ce 0.3)-Fe-B and(Nd 0.7 Ce 0.225 La 0.075)-Fe-B hot-deformed magnets were successfully improved.

关键词： Nd-Fe-B magnets Hot-deformation Nd-saving Ce-substitution La-substitution Infiltration

Delayed-onset endophthalmitis associated with Achromobacter species developed in acute form several months after cataract surgery:Three case reports

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World Journal of Clinical Cases 2022年第19期10卷 6496-6500页

作者： tae-hoon kim Sang-Joon Lee Ki-Yup Nam Department of Ophthalmology Kosin University HospitalBusan 49267South Korea Department of Ophthalmology Kosin UniversityCollege of MedicineBusan 49267South Korea Department of Ophthalmology Chungnam National UniveristyCollege of MedicineDaejeon 35015South Korea Department of Ophthalmology Chungnam National University Sejong HospitalSejong 30099South Korea

BACKGROUND Achromobacter species-associated endophthalmitis is rare and may present as either acute or chronic postoperative ***-onset Achromobacter species endophthalmitis appearing in acute presentation that develops more than several months after cataract surgery is very *** lens(IOL)removal is commonly recommended to treat Achromobacter species endophthalmitis,which is based on previous ***,we report the results of surgery without IOL removal when treating patients with delayed-onset postoperative Achromobacter species endophthalmitis that developed in an acute *** SUMMARY Three patients visited our ophthalmology clinic due to visual impairment that began 2-3 d *** had undergone cataract surgery 5-18 mo *** visual acuity of the diseased eye was between counting fingers at 30 cm to non-light *** showed conjunctival injection,inflammation in the anterior chamber(cell reaction 4+)and hypopyon *** patients were diagnosed with infectious endophthalmitis and immediately underwent pars plana vitrectomy,anterior chamber irrigation and intravitreal injection of ceftazidime and *** fluid infusion,a vitreous specimen was obtained. In all cases, the IOLs were not removed. Achromobacter species was detected on vitreousspecimen culture. After surgery, the vitreous opacity decreased gradually and there was littleretinal damage. At 1 mo after treatment, the best-corrected visual acuity had improved to 20/50and 20/*** onset postoperative endophthalmitis caused by Achromobacter species can appear in anacute form. All patients responded well to early vitrectomy and administration of empiricalantibiotics including ceftazidime. There was no need for IOL removal during surgery.

关键词： Achromobacter species Chronic endophthalmitis Postoperative endophthalmitis Case report

A conformal titanyl phosphate amorphous overlayer for enhancing photoelectrochemical hydrogen peroxide production

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Journal of Energy Chemistry 2023年第11期86卷 399-408,I0009页

作者： Jaekyum kim Young Eun kim Minyeong Je Won tae Hong Chang-Lyoul Lee tae-hoon kim Sung Min Cho Chang Hyuck Choi Heechae Choi Woo-Seok Choe Jung Kyu kim School of Chemical Engineering Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea SKKU Advanced Institute of Nano Technology(SAINT) Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Theoretical Materials&Chemistry Group Institute of Inorganic ChemistryUniversity of CologneGreinstr.650939CologneGermany Advanced Photonics Research Institute(APRI) Gwangju Institute of Science and Technology(GIST)Gwangju 61005Republic of Korea Department of Materials Science and Engineering Chonnam National UniversityGwangju 61186Republic of Korea Department of Chemistry Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea Institute for Convergence Research and Education in Advanced Technology(I-CREATE) Yonsei UniversitySeoul 03722Republic of Korea Department of Chemistry Xi’an Jiaotong-Liverpool UniversitySuzhou 215123JiangsuChina

Photoelectrochemical(PEC)H_(2)O_(2)production through water oxidation reaction(WOR)is a promising strategy,however,designing highly efficient and selective photoanode materials remains challenging due to competitive reaction ***,for highly enhanced PEC H_(2)O_(2)production,we present a conformal amorphous titanyl phosphate(a-TP)overlayer on nanoparticulate TiO_(2)surfaces,achieved via lysozyme-molded in-situ surface *** a-TP overlayer modulates surface adsorption energies for reaction intermediates,favoring WOR for H_(2)O_(2)production over the competing O_(2)evolution *** density functional theory calculations reveal that a-TP/TiO_(2)exhibits a substantial energy uphill for the O·*formation pathway,which disfavors O_(2)evolution but promotes H_(2)O_(2)***,the a-TP overlayer strengthens the built-in electric field,resulting in favorable ***,a-TP/TiO_(2)exhibits 3.7-fold higher Faraday efficiency(FE)of 63%at 1.76 V *** hydrogen electrode(RHE)under 1 sun illumination,compared to bare TiO_(2)(17%),representing the highest FE among TiO_(2)-based WOR H_(2)O_(2)production *** the a-TP overlayer constitutes a promising strategy for controlling reaction pathways and achieving efficient solar-to-chemical energy conversion.

关键词： Solar H_(2)O_(2) production In-situ surface reforming Titanyl phosphate Amorphous overlayer Reaction pathway control

Nanocrystalline Iron Pyrophosphate-Regulated Amorphous Phosphate Overlayer for Enhancing Solar Water Oxidation

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Nano-Micro Letters 2022年第12期14卷 387-400页

作者： Chengkai Xia Yuankai Li Minyeong Je Jaekyum kim Sung Min Cho Chang Hyuck Choi Heechae Choi tae-hoon kim Jung Kyu kim School of Chemical Engineering Sungkyunkwan University(SKKU)2066 Seobu-roJangan-guSuwon 16419Republic of Korea Theoretical Materials and Chemistry Group Institute of Inorganic ChemistryUniversity of CologneGreinstr.650939 CologneGermany Department of Chemistry Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea Department of Materials Science and Engineering Engineering Research CenterChonnam National UniversityGwangju 61186Republic of Korea

A rational regulation of the solar water splitting reaction pathway by adjusting the surface composition and phase structure of catalysts is a substantial approach to ameliorate the sluggish reaction kinetics and improve the energy conversion *** this study,we demonstrate a nanocrystalline iron pyrophosphate(Fe_(4)(P_(2)O_(7))_(3),FePy)-regulated hybrid overlayer with amorphous iron phosphate(FePO_(4),FePi)on the surface of metal oxide nanostructure with boosted photoelectrochemical(PEC)water *** manipulating the facile electrochemical surface treatment followed by the phosphating process,nanocrystalline FePy is localized in the FePi amorphous overlayer to form a heterogeneous hybrid *** FePy-regulated hybrid overlayer(FePy@FePi)results in significantly enhanced PEC performance with long-term *** with the homogeneous FePi amorphous overlayer,FePy@FePi can improve the charge transfer efficiency more significantly,from 60% of FePi to 79%of FePy@*** density-functional theory calculations reveal that the coexistence of FePi and FePy phases on the surface of metal oxide results in much better oxygen evolution reaction kinetics,where the FePi was found to have a typical down-hill reaction for the conversion from OH*to O_(2),while FePy has a low free energy for the formation of OH*.

关键词： Water oxidation Photoelectrochemical cell Metal pyrophosphate Electrochemical surface treatment

Injection molding of micro patterned PMMA plate

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 148-152页

作者： Yeong-Eun YOO tae-hoon kim tae-Jin JE Doo-Sun CHOI Chang-Wan kim Sun-Kyung kim Department of Nanomanufacturing Technology KIMM 171 Jang-dong Yusung-gu Daejeon 305-343 Korea Department of Product Design and Manufacturing Seoul National University of Technology

A plastic plate with surface micro features was injection molded to investigate the effect of pressure rise of melt on the replication of the micro structures. Prism pattern, which is used in many optical applications, was selected as a model pattern. The prism pattern is 50 μm in pitch and 108° in the vertical angle. The overall size of the plate was 335 minx213 mm and the thickness of the plate varied linearly from 2.6 mm to 0.7 ram. The prism pattern was firstly machined on the nickel plated core block using micro diamond tool and this machined pattern core was installed in a mold for injection molding of prism patterned plate. Polymethyl methacrylate （PMMA） was used as a molding material. The pressure and temperature of the melt in the cavity were measured at different positions in the cavity and the replication of the pattern was also measured at the same positions. The results show that the pressure or temperature profile through the process depends on the shape and the size of the plate. The replication is affected by the temperature and pressure profiles at the early stage of filling, which is right after the melt reaches the position to be measured.

关键词： micro prism pattern injection molding replication pressure profile temperature profile

Tailoring local structures of atomically dispersed copper sites for highly selective CO_(2) electroreduction

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Carbon Energy 2024年第4期6卷 79-90页

作者： Kyung‐Jong Noh Byoung Joon Park Ying Wang Yejung Choi Sang‐hoon You Yong‐tae kim Kug‐Seung Lee Jeong Woo Han Department of Chemical Engineering Pohang University of Science and Technology(POSTECH)PohangGyeongbukRepublic of Korea Department of Materials Science and Engineering Pohang University of Science and Technology(POSTECH)PohangGyeongbukRepublic of Korea Pohang Accelerator Laboratory(PAL) Beamline DivisionPohangGyeongbukRepublic of Korea

Atomically‐dispersed copper sites coordinated with nitrogen‐doped carbon(Cu–N–C)can provide novel possibilities to enable highly selective and active electrochemical CO_(2) reduction ***,the construction of optimal local electronic structures for nitrogen‐coordinated Cu sites(Cu–N_(4))on carbon remains ***,we synthesized the Cu–N–C catalysts with atomically‐dispersed edge‐hosted Cu–N_(4) sites(Cu–N_(4)C_(8))located in a micropore between two graphitic sheets via a facile method to control the concentration of metal ***‐hosted Cu–N_(4)C_(8) catalysts outperformed the previously reported M–N–C catalysts for CO_(2)‐to‐CO conversion,achieving a maximum CO Faradaic efficiency(FECO)of 96%,a CO current density of–8.97 mA cm^(–2) at–0.8 V versus reversible hydrogen electrode(RHE),and over FECO of 90%from–0.6 to–1.0 V versus *** studies revealed that the micropore of the graphitic layer in edge‐hosted Cu–N_(4)C_(8) sites causes the d‐orbital energy level of the Cu atom to shift upward,which in return decreases the occupancy of antibonding states in the*COOH *** research suggests new insights into tailoring the locally coordinated structure of the electrocatalyst at the atomic scale to achieve highly selective electrocatalytic reactions.

关键词： atomic local structure density functional theory electrochemical CO_(2)reduction metal nitrogen‐doped carbon single‐atom catalyst

Use of rotational atherectomy for reducing significant dissection in treating de novo femoropopliteal steno-occlusive disease after balloon angioplasty

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Journal of Geriatric Cardiology 2018年第4期15卷 254-260页

作者： tae-hoon kim Manny Katsetos Khagendra Dahal Michael Azrin Juyong Lee University of Connecticut Health Center Connecticut USA Sejong General Hospital Bucheon South Korea Louisiana State University Health Science Center Shreveport LA USA

Background Development of arterial dissection is thought to be an important key factor for bailout stenting in femoropopliteal disease. We aimed to evaluate the difference in dissection rate and outcomes between the treatment group with rotational atherectomy and with？out it. Methods From January 2011 to October 2016, we compared the angiography after balloon angioplasty （BA） of de-novo, femoropop？liteal, steno-occlusive lesions whether they were treated by rotational atherectomy prior to the BA or not. Fifty-nine lesions （8 occlusions; 3 involving popliteal segment; lesion length： 86.3 ± 66.8 mm） in 44 patients （29 males; mean age 66.9 ± 9.7 years） were enrolled for this review. Results Forty-two lesions were treated using rotational atherectomy, prior to BA while 17 were recanalized firstly by BA. Clinical and lesion characteristics were not different between the groups. However, the rate of significant arterial dissection （type C to F） was lower in the atherectomy group （88.2% vs. 42.9%; P = 0.001）. In multivariate analysis, use of the atherectomy device was the only risk factor for prevention of development of significant dissection （P = 0.013; OR = 0.12; 95% CI： 0.025？0.642）. Patients were treated either by the angioplasty alone, drug coated balloon or stent insertion. There was lower trend in target vessel revascularization and primary patency toward the atherectomy group （low rank P = 0.108 and 0.166）, however secondary patency was significantly better （low rank P = 0.001）. Conclusions Rotational atherec？tomy before BA reduced the rate of significant dissection and therefore, might be a valuable option for minimizing need of bailout stenting.

关键词： Arterial dissection Atherectomy Femoropopliteal disease Peripheral arterial disease

Trends in colorectal cancer incidence according to an increase in the number of colonoscopy cases in Korea

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World Journal of Gastrointestinal Oncology 2024年第1期16卷 51-60页

作者： Ga Hee kim Yeong Chan Lee tae Jun kim Sung Noh Hong Dong Kyung Chang Young-Ho kim Dong-hoon Yang Chang Mo Moon Kyunga kim Hyun Gun kim Eun-Ran kim Division of Gastroenterology Department of Internal MedicineAsan Medical CenterUniversity of Ulsan College of MedicineSeoul 05505South Korea Department of Digital Health Samsung Advanced Institute for Health Science and TechnologySungkyunkwan University School of MedicineSeoul 06351South Korea Division of Gastroenterology Department of Internal MedicineSamsung Medical CenterSungkyunkwan University School of MedicineSeoul 06351South Korea Division of Gastroenterology Department of Internal MedicineEwha Womans UniversitySeoul 07985South Korea Biomedical Statistics Center Samsung Medical CenterSeoul 06351South Korea Division of Gastroenterology Department of Internal MedicineSoonchunhyang University College of MedicineSeoul 04401South Korea

BACKGROUND The incidence of colorectal cancer(CRC)and preinvasive CRC(e.g.,early colon cancer and advanced adenoma)is gradually increasing in several *** To evaluate the trend in incidence of CRC and preinvasive CRC according to the increase in the number of colonoscopies performed in *** This retrospective cohort study enrolled Korean patients from 2002 to 2020 to evaluate the incidence of CRC and preinvasive CRC,and assess the numbers of diagnostic colonoscopies and colonoscopic ***-related complications by age group were also *** The incidence of CRC showed a rapid increase,then decreased after 2012 in the 50-75 year-age *** the study period,the rate of incidence of preinvasive CRC increased at a similar level in patients under 50 and 50-75 years of *** 2009,the increase has been rapid,showing a pattern similar to the increase in *** rate of colonoscopic polypectomy in patients aged under 50 was similar to the rate in patients over 75 years of age after *** rate of complications after colonoscopy and related deaths within 3 mo was high for those over 75 years of *** The diagnosis of preinvasive CRC increased with the increase in the number of colonoscopies *** the risk of colonoscopy-related hospitalization and death is high in the elderly,if early lesions at risk of developing CRC are diagnosed and treated under or at the age of 75,colonoscopy-related complications can be reduced for those aged 76 years or over.

关键词： Colorectal cancer Preinvasive colorectal cancer Colorectal polypectomy Colonoscopy

ROS-induced metabolic reprogramming to one-carbon metabolism and S-adenosylmethionine-mediated epigenetic modification in IL-10-producing B cells for the resolution of pneumonia

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Cellular & Molecular Immunology 2024年第2期21卷 203-204页

作者： Sujin Lee tae Jin kim Department of Immunology Sungkyunkwan University School of MedicineSuwon16419Republic of Korea

B cells have an essential immunoregulatory function,which is mediated by the secretion of IL-10 and TGFβand interaction with activated CD4^(+)T *** antibody-independent function of B cells contributes to ameliorating autoimmune diseases or infection-induced tissue *** this Cellular and Molecular Immunology issue,Fu et *** that regulatory B(Breg)cells play a critical role in resolving Pseudomonas aeruginosa-induced pneumonia[1].

关键词： metabolism pneumonia Immunology