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High-throughput computational-experimental screening protocol for the discovery of bimetallic catalysts

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npj Computational Materials 2021年第1期7卷 1232-1241页

作者： Byung Chul Yeo Hyunji nam Hyobin nam Min-Cheol kim Hong Woo Lee Sung-Chul kim Sung Ok Won Donghun kim Kwan-Young Lee Seung Yong Lee Sang Soo Han Computational Science Research Center Korea Institute of Science and TechnologySeoulRepublic of Korea Department of Energy Resources Engineering Pukyong National UniversityBusanRepublic of Korea Materials Architecturing Research Center Korea Institute of Science and TechnologySeoulRepublic of Korea Department of Chemical and Biological Engineering Korea UniversitySeoulRepublic of Korea Department of Nanomaterials Science and Engineering Korea University of Science and TechnologyDaejeonRepublic of Korea Advanced Analysis Center Korea Institute of Science and TechnologySeoulRepublic of Korea

To accelerate the discovery of materials through computations and experiments,a well-established protocol closely bridging these methods is *** introduce a high-throughput screening protocol for the discovery of bimetallic catalysts that replace palladium(Pd),where the similarities in the electronic density of states patterns were employed as a screening *** first-principles calculations,we screened 4350 bimetallic alloy structures and proposed eight candidates expected to have catalytic performance comparable to that of *** experiments demonstrate that four bimetallic catalysts indeed exhibit catalytic properties comparable to those of ***,we discover a bimetallic(Ni-Pt)catalyst that has not yet been reported for H_(2)O_(2) direct *** particular,Ni_(61)Pt_(39) outperforms the prototypical Pd catalyst for the chemical reaction and exhibits a 9.5-fold enhancement in cost-normalized *** protocol provides an opportunity for the catalyst discovery for the replacement or reduction in the use of the platinum-group metals.

关键词： synthesis catalyst bimetallic

Prediction models for recurrence in patients with small bowel bleeding

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World Journal of Clinical Cases 2023年第17期11卷 3949-3957页

作者： Ji Hyun kim Seung-Joo nam Division of Gastroenterology and Hepatology Department of Internal MedicineKangwon National University School of MedicineChuncheon 24341South Korea

Obscure gastrointestinal bleeding(OGIB)has traditionally been defined as gastrointestinal bleeding whose source remains unidentified after bidirectional *** can present as overt bleeding or occult bleeding,and small bowel lesions are the most common *** small bowel can be evaluated using capsule endoscopy,device-assisted enteroscopy,computed tomography enterography,or magnetic resonance *** the cause of smallbowel bleeding is identified and targeted therapeutic intervention is completed,the patient can be managed with routine ***,diagnostic tests may produce negative results,and some patients with small bowel bleeding,regardless of diagnostic findings,may experience *** those at risk of rebleeding can help clinicians form individualized surveillance *** studies have identified different factors associated with rebleeding,and a limited number of studies have attempted to create prediction models for *** article describes prediction models developed so far for identifying patients with OGIB who are at greater risk of *** models may aid clinicians in forming tailored patient management and surveillance.

关键词： Obscure gastrointestinal bleeding Prediction model Rebleeding Small bowel bleeding Video capsule endoscopy

Late Pleistocene spore-pollen record and climatic change at the Chongphadae Cave Site,Democratic People's Republic of Korea

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Journal of Palaeogeography 2023年第4期12卷 624-636页

作者： Se Chan kim Rye Sun Choe Il nam kim Chol U Ryong Il Kang Institute of Human Evolution and Development History Faculty of HistoryKim Il Sung UniversityTaesong DistrictPyongyangDemocratic People's Republic of Korea

We present a detailed pollen record and interpretations of late Pleistocene climatic change at the Chongphadae Cave Site, Democratic People's Republic of Korea. The mean annual paleotemperature and mean annual paleoprecipitation of the site were calculated using the temperature index and precipitation index based on ecological features and geographical distribution of each taxon. Temperature index and precipitation index range from 8.8℃ to 10.4℃ and from 805.0 mm to 963.1 mm, respectively. Four dates(radiocarbon, uranium series, fission track, and paleomagnetic excursion dating) of the deposit profile investigated yield a range of ~21.3 ka BP to ~117 ka BP, geochronologically corresponding to the late Pleistocene, and extend from the last interglacial highstand through the Last Glacial Maximum. Our results are thus consistent with the climatic shift from interglacial to glacial conditions, provide evidence that the environments of the region, which was reconstructed from the paleoclimatic index, changed from a mild and humid to a cool and dry climate during the late Pleistocene, and suggest trends similar to those of several parts of the Northern Hemisphere which lie in the same latitudinal zone as our study area.

关键词： Chongphadae cave Pollen Climatic change Late Pleistocene Mean annual temperature Mean annual precipitation

Cytoprotective effects of Morinda offucinalis against hydrogen peroxide-induced oxidative stress in Leydig TM3 cells

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Asian Journal of Andrology 2008年第4期10卷 667-674页

作者： Mun-Seog Chang Won-nam kim Woong-Mo Yang Hyu-Young kim Ji-Hoon Oh Seong-kyu Park Department of Prescriptionology College of Oriental Medicine Kyung Hee University Seoul 130-701 Korea

Aim： To investigate the antioxidant effects of Morinda officinalis （Morindae radix, MR） on H2O2-induced oxidative stress in cultured mouse TM3 Leydig cells. Methods： We carried out 2,2-diphenyl-1-picrylhydrazyl free radical scavenging, 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide, lipid peroxidation, testosterone enzyme immunoassay, superoxide dismutase （SOD）, and catalase （CAT） assays in Leydig TM3 cells. Results： MR showed a 47.8% 2,2-diphenyl-1-picrylhydrazyl radical scavenging effect in TM3 cells with no significant cytotoxicity. Oxidative stress was induced in TM3 cells with 100 μmol H2O2, and treatment of the cells with 250 μg/mL MR showed the most significant protective effect （64%, P 〈 0.001） in the cell viability assay with a decreased lipid peroxidation level （1.75 nmol/mg protein, P 〈 0.05）, increased testosterone production （43.5 pg/mL）, and improvements in SOD activity （7.49 units of SOD/mg protein, P 〈 0.001） and CAT activity （74.6 units of CAT/mg protein, P 〈 0.001）. Conclusion： These findings indicate that MR, as an antioxidant, protects functions of cultured mouse TM3 Leydig cells from H2O2-induced oxidative stress.

关键词： Morindae radix Leydig cell testosterone hydrogen peroxide antioxidant

Ruled Real Hypersurfaces of A Complex Space Form

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Acta Mathematica Sinica,English Series 1994年第4期10卷 401-409页

作者： Ki, U-Hang kim, nam-Gil Department of Mathematics Kyungpook University Taegu Korea Department of Mathematics Chosun University Kwangju Korea

The purpose of this paper is to define a ruled real hypersurface of a complex space form M_n(c),c≠0,and to give characterizations of this hypersurface by the infinitesimal affine transformation of the structure vecto... 详细信息

关键词： Math real Ruled Real Hypersurfaces of A Complex Space Form

Ni Single Atoms and Ni Phosphate Clusters Synergistically Triggered Surface-Functionalized MoS_(2)Nanosheets for High-performance Freshwater and Seawater Electrolysis

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Energy & Environmental Materials 2022年第4期5卷 1340-1349页

作者： Min Sung kim Duy Thanh Tran Thanh Hai Nguyen Van An Dinh nam Hoon kim Joong Hee Lee Department of Nano Convergence Engineering Jeonbuk National UniversityJeonju 54896Republic of Korea Department of Precision Engineering Graduate School of EngineeringOsaka University2-1Yamada-okaSuita 565-0871Japan Carbon Composite Research Center Department of Polymer-Nanoscience and TechnologyJeonbuk National UniversityJeonju 54896Republic of Korea

Two-dimensional metal dichalcogenides have been evidenced as potential electrocatalysts for hydrogen evolution reaction(HER);however,their application is limited by a poor oxygen evolution reaction(OER)activity due to insufficient number/types of multi-integrated active *** this study,we report a novel bifunctional catalyst developed by simultaneous engineering of single nickel atoms(Ni_(SA)) and nickel phosphate clusters(Ni_(Pi)) to synergistically trigger surface-functionalized MoS_(2) nanosheets(NSs)resulting in high reactivities for both HER and *** Ni_(SA)-Ni_(Pi)/MoS_(2)NSs material exhibits a fairly Pt-like HER behavior with an overpotential of 94.0 mV and a small OER overpotential of 314.0 mV to reach 10 mA cm^(-2) in freshwater containing 1.0 M *** results of the catalyst are well supported by theoretical study,which reveals the significant modulation of electronic structure and enrichment of electroactive site number/types with their reasonably adjusted free adsorption *** evaluating practicability,the Ni_(SA)-Ni_(Pi)/MoS_(2)NSs-based electrolyzer delivers effective operation voltage of 1.62,1.52,and 1.66 V at 10 mA cm^(-2) and superior long-term stability as compared to Pt/C//RuO_(2) system in freshwater,mimic seawater,and natural seawater,*** present study indicates that the catalyst is a promising candidate for the practical production of green hydrogen via water electrolysis.

关键词： bifunctional electrocatalyst freshwater and seawater electrolysis nickel phosphate clusters nickel single atoms surface-functionalized-MoS_(2)nanosheets

Vertical plane depth-resolved surface potential and carrier separation characteristics in flexible CZTSSe solar cells with over 12% efficiency

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Carbon Energy 2024年第3期6卷 36-52页

作者： Dae-Ho Son Ha kyung Park Dae-Hwan kim Jin-kyu Kang Shi-Joon Sung Dae-Kue Hwang Jaebaek Lee Dong-Hwan Jeon Yunae Cho William Jo Taeseon Lee JunHo kim Sang-Hoon nam Kee-Jeong Yang Division of Energy Technology DGISTDaeguRepublic of Korea Research Center for Thin Film Solar Cells DGISTDaeguRepublic of Korea Department of Physics Ewha Womans UniversitySeoulRepublic of Korea Department of Physics Incheon National UniversityIncheonRepublic of Korea Department of Mechanical Engineering Massachusetts Institute of TechnologyCambridgeMassachusettsUSA

Cu2ZnSn(S,Se)4(CZTSSe)solar cells have resource distribution and economic *** main cause of their low efficiency is carrier loss resulting from recombination of photo-generated electron and *** overcome this,it is important to understand their electron-hole behavior *** determine the carrier separation characteristics,we measured the surface potential and the local current in terms of the absorber *** elemental variation in the intragrains(IGs)and at the grain boundaries(GBs)caused a band edge shift and bandgap(Eg)*** the absorber surface and subsurface,an upward Ec and Ev band bending structure was observed at the GBs,and the carrier separation was *** the absorber center,both upward Ec and Ev and downward Ec-upward Ev band bending structures were observed at the GBs,and the carrier separation was *** improve the carrier separation and suppress carrier recombination,an upward Ec and Ev band bending structure at the GBs is desirable.

关键词： carrier separation CZTSSe flexible solar cell local current surface potential

Lamellar sulfonated acid polymer-initiated in situ construction of robust LiF-rich SEI enabling superior charge transport for ultrastable and fast charging silicon anodes

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Journal of Energy Chemistry 2024年第11期98卷 134-143页

作者： Jungsoo Park Song kyu Kang Junhyuk Ji Hwichan Ahn Gwan Hyeon Park Minho kim Won Bae kim Graduate Institute of Ferrous&Eco Materials Technology(GIFT) Pohang University of Science and Technology(POSTECH)77 Cheongam-roNam-guPohang-siGyeongsangbuk-do 37673Republic of Korea Department of Chemical Engineering Pohang University of Science and Technology(POSTECH)77 Cheongam-RoNam-guPohang-siGyeongsangbuk-do 37673Republic of Korea

The extreme volume expansion of the silicon(Si) anodes during repeated cycles seriously induces undesirable interfacial side reactions,forming an unstable solid electrolyte interphase(SEI) that degrades the electrode integrity and cycle stability in lithium-ion batteries,limiting their practical *** considerable efforts to stabilize the SEI through surface modification,challenges persist in the development of high-performance Si anodes that effectively regulate intrinsic SEI properties and simultaneously facilitate electron/ion ***,a highly conductive and organic electrolyte-compatible lamellar p-toluenesulfonic acid-doped polyaniline(pTAP) layer is proposed for constructing a robust artificial SEI on Si nanoparticles to achieve fast charging,lo ng-term cycle lifespan and high areal *** spatially uniform pTAP layer,formed through a facile direct-encapsulation approach assisted by enriched hydrogen bonding,contributes to the effective formation of in situ SEI with an even distribution of the LiF-rich phase in its interlamination ***,the integrated artificial SEI facilitates isotropic ion/electron transport,increased robustness,and effectively dissipates stress from volume ***,a notably high rate performance of 570 mA h g^(-1),even at a substantially high current density of 10 A g^(-1),is achieved with excellent cyclic stability by showing a superior capacity over 1430 mA h g^(-1) at 1 A g^(-1) after 250 cycles and a high areal capacity of ca.2 mA h cm^(-2) at 0.5 C in a full cell *** study demonstrates that the rational design of conductive polymers with SEI modulation for surface protection has great potential for use in high-energy-density Si anodes.

关键词： Lithium-ion battery Silicon anode Conductive polymers Solid electrolyte interphase

Habitat Use, Home Range, and Hibernaculum of the Mongolian Racerunner, Eremias argus (Lacertidae, Reptilia) in a Coastal Sand Dune in South Korea

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Asian Herpetological Research 2012年第2期3卷 133-140页

作者： Il-Hun kim nam-Yong RA Daesik PARK Department of Biology Kangwon National University Division of Science Education Kangwon National University

Information on habitat use is critical in sizing protected areas for endangered reptile species. To investigate habitat use, home range, and hibernaculum of the endangered Mongolian Racerunner(Eremias argus), we radio-tracked 40 specimens in a coastal sand dune in South Korea. Of the 163 locations recorded during the breeding season, 150(92.0%) were in grass sand dunes, and the rest(8.0%), all associated with the same lizard, were in shrub sand dunes. All of the 123 locations recorded during the non-breeding season were in grass sand dunes. No lizards were found in the grasslands abutting the dunes. The four lizards with identifiable hibernation sites were found under an average of 17.8 cm of sand and were all located in grass sand dunes. The lizards moved approximately 5 m daily and used 162 m2of home range(computed by minimum convex polygon, MCP) during the breeding season, and they moved approximately 2 m and used 68 m2of home range during the non-breeding season. However, the mean daily moved distances and MCP home ranges were not statistically significantly different between the seasons or between males and females. Our results suggest that in coastal sand dunes, E. argus uses grass sand dunes as its main habitat throughout the year. This finding could be used to determine the appropriate habitat size and to designate for the conservation of this endangered species.

关键词： coastal sand dune spatial ecology Eremias argus lizard radio-telemetry