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Oxygen vacancy engineering for tuning the catalytic activity of LaCoO_(3) perovskite

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Journal of Rare Earths 2024年第3期42卷 506-514,I0003页

作者： Jeong hyun Cho Minjae Kim Inchan Yang Kyung tae Park chang Houn Rhee Hai Woong Park Ji Chul Jung Department of Chemical Engineering Myongji UniversityYongin 17058Republic of Korea Institute of Advanced Composite Materials Korea Institute of Science and TechnologyWanju-gunJeollabuk-do 55324Republic of Korea Iron&Steel Process Engineering Research Group POSCOPohang 37859Republic of Korea Hydrogen Research Center Research Institute of Industrial Science&Technology(RIST)Pohang 37673Republic of Korea

Herein, we attempted to engineer oxygen vacancies on the surface of LaCoO_(3) perovskite through simple post-treatments(acid or reductive thermal treatments). Acid treatment induces oxygen vacancies through the selective etching of the La cations, whereas thermal treatment in a reducing atmosphere generates oxygen vacancies by directly removing lattice oxygen. The characterization results confirm that the number of surface oxygen vacancies, which are crucial in various catalytic oxidation reactions,considerably increases in the LaCoO_(3) catalysts treated with acid or reducing gas. Acid treatment enriches the oxygen vacancies while maintaining the structure of the LaCoO_(3) catalysts, which can not be achieved through reductive thermal treatment. Therefore, the acid treatment is considered a promising technique for oxygen vacancy engineering of perovskite catalysts for tuning their catalytic activities. Furthermore,the catalytic activities of the posttreated LaCoO_(3) catalysts for CO oxidation were evaluated and are noted to be considerably better than those of the pristine LaCoO_(3) catalyst due to their abundant oxygen vacancies. Consequently, we conclude that the oxygen vacancies of perovskite catalysts can be effectively engineered via two simple methods and play a significant role in CO oxidation.

关键词： LaCoO_(3)perovskite Acid treatment Reductive thermal treatment Oxygen vacancy CO oxidation Rare earths

Velocity Profiles between Two Baffles in a Horizontal Circular Tube

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Journal of Thermal Science 2014年第6期23卷 544-551页

作者： tae-hyun chang Hae-Soo Lee Keon-Je Oh Doeg Hee Doh chang-Hoan Lee Senior Research Fellow of RESEAT Korea Institute of Science and Information Postdoctoral Research Fellow School of Mechanical Engineering of Kyungnam University School of Mechanical Engineering Kyungnam University Division of Mechanical and Energy Systems Engineering Korea Marine and Ocean University Korea Institute of Science and Technology Information

The shell and tube heat exchanger is an essential part of a power plant for recovering heat transfer between the feed water of a boiler and the wasted *** baffles are also an important element inside the heat *** materials influence the flow pattern in the *** influence of baffles in the velocity profiles was observed using a three-dimensional particle image velocimetry around baffles in a horizontal circular *** velocity of the particles was measured before the baffle and between them in the test *** show that the flows near the front baffle flow were parallel to the vertical wall,and then concentrate on the upper opening of the front *** flows circulate in the front and rear *** flow profiles are related to the Reynolds number(Re) or the flow *** velocity profiles at lower Re number showed a complicated mixing,concentrating on the lower opening of the rear baffle as front *** flow was employed in this study,which was produced using tangential velocities at the *** the entrance of the front baffle,the velocity vector profiles with swirl were much different from that without ***,velocities between two baffles are not much different from those without swirl.

关键词：速度剖面水平圆管隔板粒子图像测速流动模式管壳式换热器组成部分回收锅炉

Two-stage dynamic recrystallization and texture evolution in Al-7Mg alloy during hot torsion

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1900-1911页

作者： Kwang tae Son chang Hee Cho Myoung Gyun Kim Ji Woon Lee School of Mechanical Industrialand Manufacturing EngineeringOregon State UniversityCorvallis OR 97331USA Department of Materials Science Engineering Northwestern UniversityEvanston IL 60208USA Research Institute of Industrial Science and Technology(RIST) Pohang 37673Rep.of Korea Division of Advanced Materials Engineering Kongju National UniversityCheonan 31080Rep.of Korea Center for Advanced Materials and Parts of Powders Kongju National UniversityCheonan 31080Rep.of Korea

Hot torsion tests were performed on the Al-7Mg alloy at the temperature ranging from 300 to 500℃ and strain rates between 0.05 and 5 s^(-1) to explore the progressive dynamic recrystallization(DRX)and texture *** DRX behavior of the alloy manifested two distinct stages:Stage 1 at strain of≤2 and Stage 2 at strains of≥*** Stage 1,there was a slight increase in the DRXed grain fraction(X_(DRX))with predominance of discontinuous DRX(DDRX),followed by a modest change in X_(DRX) until the transition to Stage *** 2 was marked by an accelerated rate of DRX,culminating in a substantial final X_(DRX) of~*** backscattered diffraction(EBSD)analysis on a sample in Stage 2 revealed that continuous DRX(CDRX)predominantly occurred within the(121)[001]grains,whereas the(111)[110]grains underwent a geometric DRX(GDRX)evolution without a noticeable sub-grain ***,a modified Avrami’s DRX kinetics model was utilized to predict the microstructural refinement in the Al-7Mg alloy during the DRX *** this kinetics model did not accurately capture the DDRX behavior in Stage 1,it effectively simulated the DRX rate in Stage *** texture index was employed to assess the evolution of the texture isotropy during hot-torsion test,demonstrating significant improvement(>75%)in texture randomness before the commencement of Stage *** initial texture evolution is attributed to the rotation of parent grains and the substructure evolution,rather than to an increase in X_(DRX).

关键词： Al-7Mg alloys hot deformation hot torsion tests dynamic recrystazlliation microstructure texture

Inclusive quasielastic neutrino-nucleus scattering with energy density functional nuclear models

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Chinese Physics C 2024年第8期48卷 153-158页

作者： K.S.Kim Soonchul Choi Hana Gil chang Ho hyun School of liberal arts and science korea aerospace universitygoyang 10540korea Center for exotic nuclear studies institute for basic sciencedaejeon 34126korea Center for extreme nuclear matters korea universityseoul 02841korea Department of physics education daegu universitygyeongsan 38453korea

In this study,we calculated the inclusive charged-current neutrino-nucleus scattering from ^(40)Ar in the quasielastic *** explore the effect of uncertainties stemming from the nuclear structure,we used the KIDS(Korea-IBS-Daegu-SKKU)nuclear energy density functional and Skyrme force models,namely SLy4,SkI3,and *** models were selected to have distinct behavior in terms of the density dependence of the symmetry energy and the effective mass of the *** the charged-current neutrino scattering,the single-and double-differential cross sections were calculated for various *** cross sections are reported as a function of the incident neutrino *** theoretical cross sections were compared with experimental data,and the roles of the effective mass and symmetry energy were investigated in terms of charged-current neutrino-nucleus scattering.

关键词： energy density functional neutrino-nucleus scattering symmetry energy effective mass of the nucleon

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

Endoscopic ultrasound-guided tissue sampling induced pancreatic duct leak resolved by the placement of a pancreatic stent:A case report

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World Journal of Clinical Cases 2024年第9期12卷 1677-1684页

作者： Ki-hyun Kim chang Hwan Park Eunae Cho Yohan Lee Department of Internal Medicine Chonnam National University HospitalGwangju 61469South Korea Department of Gastroenterology Chonnam National University HospitalGwangju 61469South Korea

BACKGROUND Pancreatic ductal leaks complicated by endoscopic ultrasonography-guided tissue sampling(EUS-TS)can manifest as acute *** SUMMARY A 63-year-old man presented with persistent abdominal pain and weight ***:Laboratory findings revealed elevated carbohydrate antigen 19-9(5920 U/mL)and carcinoembryonic antigen(23.7 ng/mL)*** resonance imaging of the pancreas revealed an approximately 3 cm ill-defined space-occupying lesion in the inferior aspect of the head,with severe encasement of the superior mesenteric *** ductal adenocarcinoma was confirmed after pathological examination of specimens obtained by EUS-TS using the fanning *** and outcomes:The following day,the patient experienced severe abdominal pain with high amylase(265 U/L)and lipase(1173 U/L)*** tomography of the abdomen revealed edematous wall thickening of the second portion of the duodenum with adjacent fluid collections and a suspicious leak from either the distal common bile duct or the main pancreatic duct in the *** retrograde cholangiopancreatography revealed dye leakage in the head of the main pancreatic ***,a 5F 7 cm linear plastic stent was deployed into the pancreatic duct to divert the pancreatic *** patient’s abdominal pain improved immediately after pancreatic stent insertion,and amylase and lipase levels normalized within a *** chemotherapy was then *** Using the fanning method in EUS-TS can inadvertently cause damage to the pancreatic duct and may lead to clinically significant *** a pancreatic stent may immediately resolve acute pancreatitis and shorten the waiting time for curative *** using the fanning method during EUSTS,ductal structures should be excluded to prevent pancreatic ductal leakage.

关键词： Endoscopic ultrasound-guided tissue sampling Pancreatitis Pancreatic duct leak Pancreatic stent Case report

Capsosiphon fulvescens suppresses LPS-stimulated inflammatory responses by suppressing TLR4/NF-κB activation in RAW264.7 murine macrophages

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Asian Pacific Journal of Tropical Biomedicine 2024年第3期14卷 115-126页

作者： Seon Yeong Ji EunJin Bang hyun Hwangbo Min Yeong Kim Da Hye Kim Su hyun Hong Shin-hyung Park chang-Young Kwon Gi-Young Kim You-Jin Jeon Suengmok Cho Yung hyun Choi Department of Biochemistry Dong-eui University College of Korean MedicineBusan 47227Republic of Korea Basic Research Laboratory for the Regulation of Microplastic-Mediated Diseases and Anti-Aging Research Center Dong-eui UniversityBusan 47227Republic of Korea Department of Pathology Dong-eui University College of Korean MedicineBusan 47227Republic of Korea Department of Oriental Neuropsychiatry Dong-eui University College of Korean MedicineBusan 47227Republic of Korea Department of Marine Life Science Jeju National UniversityJeju 63243Republic of Korea Department of Food Science and Technology/Institute of Food Science Pukyong National UniversityBusan 48513Republic of Korea

Objective:To evaluate the effects of Capsosiphon fulvescens(***)ethanolic extract on inflammation in lipopolysaccharide(LPS)-induced RAW296.7 ***:The protective effects of *** ethanolic extract on LPS-induced inflammation in RAW264.7 macrophages were assessed using biochemical analysis,including enzyme-linked immunosorbent assay,quantitative reverse transcription-polymerase chain reaction,and Western blot *** examine reactive oxygen species(ROS)production,flow cytometry analysis,and immunofluorescence staining were ***,the modulatory effect of *** ethanolic extract on NF-κB activation was ***:*** ethanolic extract significantly attenuated LPS-induced levels of pro-inflammatory cytokines and notably reduced the secretion and mRNA levels of LPS-mediated matrix *** addition,*** ethanolic extract decreased ROS production and suppressed the TLR4/NF-κB signaling ***:*** ethanolic extract alleviates inflammation as well as oxidative stress by modulating the TLR4/NF-κB signaling in LPS-induced RAW264.7 *** can be used as a potential therapeutic agent to suppress inflammation and oxidative stress-associated diseases.

关键词： Capsosiphon fulvescens Inflammation Oxidative stress NF-κB Nrf2 TLR4

Stable immobilization of lithium polysulfides using three-dimensional ordered mesoporous Mn2O3 as the host material in lithium-sulfur batteries

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Carbon Energy 2024年第6期6卷 99-112页

作者： Sung Joon Park Yun Jeong Choi hyun-seung Kim Min Joo Hong Hongjun chang Janghyuk Moon Young-Jun Kim Junyoung Mun Ki Jae Kim Department of Energy Science Sungkyunkwan UniversitySuwonGyeonggi-doRepublic of Korea Department of Energy Engineering Konkuk UniversitySeoulRepublic of Korea Advanced Batteries Research Center Korea Electronic Technology InstituteSeongnamRepublic of Korea Department of Future Energy Engineering Sungkyunkwan UniversitySuwonRepublic of Korea Department of Energy Systems Engineering Chung-Ang UniversitySeoulRepublic of Korea SKKU Advanced Institute of Nanotechnology Sungkyunkwan UniversitySuwonGyeonggi-doRepublic of Korea SKKU Institute of Energy Science and Technology(SIEST) Sungkyunkwan UniversitySuwonRepublic of Korea School of Advanced Materials Science and Engineering Sungkyunkwan UniversitySuwonRepublic of Korea

Lithium-sulfur batteries(LSBs)have drawn significant attention owing to their high theoretical discharge capacity and energy ***,the dissolution of long-chain polysulfides into the electrolyte during the charge and discharge process(“shuttle effect”)results in fast capacity fading and inferior electrochemical *** this study,Mn_(2)O_(3)with an ordered mesoporous structure(OM-Mn_(2)O_(3))was designed as a cathode host for LSBs via KIT-6 hard templating,to effectively inhibit the polysulfide shuttle ***-Mn_(2)O_(3)offers numerous pores to confine sulfur and tightly anchor the dissolved polysulfides through the combined effects of strong polar-polar interactions,polysulfides,and sulfur chain *** OM-Mn_(2)O_(3)/S composite electrode delivered a discharge capacity of 561 mAh g-1 after 250 cycles at 0.5 C owing to the excellent performance of OM-Mn_(2)O_(3).Furthermore,it retained a discharge capacity of 628mA h g-1 even at a rate of 2 C,which was significantly higher than that of a pristine sulfur electrode(206mA h g-1).These findings provide a prospective strategy for designing cathode materials for high-performance LSBs.

关键词： host material lithium-sulfur battery ordered mesoporous structure shuttle effect transition-metal oxides

Understanding the correlation between energy-state mismatching and open-circuit voltage loss in bulk heterojunction solar cells

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Carbon Energy 2024年第5期6卷 164-174页

作者： hyun-Seock Yang Danbi Kim chang-Mok Oh Vellaiappillai Tamilavan Pesi MHangoma Hojun Yi Bo RLee Insoo Shin In-Wook Hwang Sung Heum Park Pukyong National University BusanRepublic of Korea Clarendon Laboratory University of OxfordOxfordUK Institute of Energy Transport and Fusion Research Pukyong National UniversityBusanRepublic of Korea Advanced Photonics Research Institute Gwangju Institute of Science and TechnologyGwangjuRepublic of Korea Department of Chemical and Biomolecular Engineering Tandon School of EngineeringNew York UniversityBrooklynNew YorkUSA

Photoinduced intermolecular charge transfer(PICT)determines the voltage loss in bulk heterojunction(BHJ)organic photovoltaics(OPVs),and this voltage loss can be minimized by inducing efficient PICT,which requires energy-state matching between the donor and acceptor at the BHJ ***,both geometrically and energetically accessible delocalized state matching at the hot energy level is crucial for achieving efficient *** this study,an effective method for quantifying the hot state matching of OPVs was *** degree of energy-state matching between the electron donor and acceptor at BHJ interfaces was quantified using a mismatching factor(MF)calculated from the modified optical density of the ***,the correlation between the open-circuit voltage(Voc)of the OPV device and energy-state matching at the BHJ interface was investigated using the calculated *** OPVs with small absolute MF values exhibited high Voc *** result clearly indicates that the energy-state matching between the donor and acceptor is crucial for achieving a high Voc in *** the MF indicates the degree of energy-state matching,which is a critical factor for suppressing energy loss,it can be used to estimate the Voc loss in OPVs.

关键词： bulk heterojunction open circuit voltage organic photovoltaics photoinduced charge transfer voltage loss