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Journal of Rare Earths 2006年第Z1期24卷 131-135页

作者： Soo woo Kwon woo seok yang H M Lee woo Kyung Kim Hang Yong Lee Dae Ho Yoon Yo Seung Song Department of Materials Engineering Hankuk Aviation UniversityGoyang 412-791Korea Nano Bio-Photonics Team Korea Electronics Technology InstituteBundang 463-816Korea Department of Advanced Material Engineering Sungkyunkwan UniversitySuwon 440-746Korea

The Ti-doped waveguide-type periodically poled LiNbO_(3)(PPLN)were fabricated and the dependence of domain wall velocity on an external field applied for domain inversion was *** whole polarization reversal process was computer-controlled to regulate domain wall expansion at a feedback time shorter than 5μ*** coercive voltage and several values of excess voltage were applied on 500μm-thick wafers serially connected to a 1-MOhm external resistor which had an effect of the poling current reduction,*** deceleration of domain wall *** domain wall velocity is sensitive to the poling voltage,precisely speaking,to the excess *** domain wall velocities were 28.70,16.02 and 5.75μm·s^(-1)under poling field of 23.5,22.0 and 21.0 kV·mm^(-1),***,average duty cycle of PPLN is about 49.93%.

关键词： periodically poled lithium niobate coerciv field duty cycle domain wall velocity quasi phase matching

Development of immature ovarian teratoma after mature teratoma in a girl with familial ovarian teratoma:A case report

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World Journal of Clinical Cases 2024年第8期12卷 1442-1447页

作者： U Chul Ju woo Dae Kang seok Mo Kim Department of Obstetrics and Gynecology Chonnam National University Medical SchoolGwangju 61469South Korea

BACKGROUND Immature ovarian teratoma is a rare and aggressive neoplasm that affects young *** report is the first to describe the development of immature teratoma after ovarian cystectomy for mature teratoma of the ovary in an adolescent female with a family history of ovarian *** SUMMARY A 16-year-old girl who had undergone bilateral ovarian cystectomy for mature teratomas 3 years ago showed bilateral adnexal tumors during her regular ultrasonography follow-up every 6 *** received laparoscopic bilateral ovarian cystectomy,and final histopathology showed grade-1 immature teratoma of the left ovary and mature teratoma of the right *** left salpingo-oophorectomy and staging procedures were performed *** mother,maternal aunt,and maternal grandmother had also received surgeries for mature ovarian *** It is important to have guidance on management of patient and family members with familial ovarian teratomas.

关键词： Familial ovarian teratomas Adolescent female Immature ovarian teratoma Management Case report

MoP nanoparticles encapsulated in N-doped carbon nanotubes as sulfur host for advanced lithium-sulfur batteries

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Nano Research 2024年第4期17卷 2736-2745页

作者： Guozhi Wu Shanqing Li Zheng Chen Ajiao Sun Jie yang Sang woo Joo Jiarui Huang Key Laboratory of Functional Molecular Solids of the Ministry of Education Anhui Laboratory of Molecule-Based MaterialsCollege of Chemistry and Materials ScienceAnhui Normal UniversityWuhu 241002China Anhui Engineering Research Center of Highly Reactive Micro-Nano Powders School of Materials and Environmental engineeringChizhou UniversityChizhou 247000China School of Mechanical Engineering Yeungnam UniversityGyeongsanGyeongbuk 38541Republic of Korea

The low electrical conductivity of sulfur,strong volume expansion,shuttle effect,and sluggish redox reactions in Li-S batteries limit their practical *** nanoparticles encapsulated in nitrogen-doped carbon nanotubes(MoP/NC NTs)were synthesized using MoO_(3) nanorods as templates via a polypyrrole coating,heat-carbonization,MoO_(3) partial reduction,ammonia washing,and *** MoP/NC NTs had a hollow nanostructure with a high specific surface area,which can alleviate the volume expansion of the cathode and the shuttle effect of *** encapsulated MoP nanoparticles can anchor the polysulfides and enhance the redox reaction ***,the MoP/NC NTs combined with sulfur(MoP/S/NC NTs)exhibited 440.8 mAh·g^(-1) over 500 cycles at 1.0 A·g^(-1) with a decay rate of 0.06%per *** density functional theory calculations and X-ray photoelectron spectroscopy results confirmed that MoP/NC NTs could anchor polysulfides and alleviate the shuttle effect by chemical *** study supplies a novel route to prepare nanoparticle-embedded in N-doped carbon nanotubes for advanced Li-S battery.

关键词： MoP N-doped carbon nanotube lithium-sulfur battery cathode

In-situ formation of MOF derived mesoporous Co3N/amorphous N-doped carbon nanocubes as an efficient electrocatalytic oxygen evolution reaction

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Nano Research 2019年第7期12卷 1605-1611页

作者： Bong Kyun Kang Seo Young Im Jooyoung Lee Sung Hoon Kwag seok Bin Kwon SintayehuNibret Tiruneh Min-Jun Kim Jung Ho Kim woo seok yang Byungkwon Lim Dae Ho Yoon Nano Materials and Components Research Center Korea Electronics Technology InstituteSeongnam 463-816Republic of Korea School of Advanced Materials Science and Engineering Sungkyunkwan University Suwon 440-746Republic of Korea Advanced Materials & Processing Center Institute for Advanced Engineering (IAE)Yongin 175-28Republic of Korea Australian Institute for Innovative Materials (AIIM) University of WollongongSquires WayNorth Wollongong NSW 2500Australia Department of Advanced Materials Engineering for Information and Electronics Kyung Hee University1732 Deogyeong-daeroGiheung-guYongin-siGyeonggi-do17104Republic of Korea

The suitable materials,metal nitrides,are a promising class of electrocatalyst materials for a highly efficient oxygen evolution reaction (OER) because they exhibit superior intrinsic conductivity and have higher sustainability than oxide-based *** our knowledge,for the first time,we report a designable synthesis of three-dimensional (3D) and mesoporous Co3N@ amorphous N-doped carbon (AN-C) nanocubes (NCs) with well-controlled open-framework structures via monodispersed Co3[Co(CN)6]2 Prussian blue analogue (PBA) NC precursors using in situ nitridation and calcination ***3N@AN-C NCs (2 h) demonstrate better OER activity with a remarkably low Tafel plot (69.6 mV-dec-1),low overpotential of 280 mV at a current density of 10 ***,excellent cycling stability in alkaline electrolytes was exhibited without morphological changes and voltage elevations,superior to most reported hierarchical structures of transition-metal nitride *** presented strategy for synergy effects of metal-organic frameworks (MOFs)-derived transition-metal nitrides-carbon hybrid nanostructures provides prospects for developing high-performance and advanced electrocatalyst materials.

关键词： transition-metal nitride metal organic framework mesoporous oxygen evaluation reaction alkaline water electrolysis

Potential reduction in carbon fixation capacity under climate change in a Pinus koraiensis forest

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Forest Ecosystems 2024年第2期11卷 152-161页

作者： Dong Kook woo Department of Civil Engineering Keimyung UniversityDaegu42601Republic of Korea

There has been an increasing recognition of the crucial role of forests, responsible for sequestering atmospheric CO_(2), as a moral imperative for mitigating the pace of climate change. The complexity of evaluating climate change impacts on forest carbon and water dynamics lies in the diverse acclimations of forests to changing environments. In this study, we assessed two of the most common acclimation traits, namely leaf area index and the maximum rate of carboxylation(V_(cmax)), to explore the potential acclimation pathways of Pinus koraiensis under climate change. We used a mechanistic and process-based ecohydrological model applied to a P. koraiensis forest in Mt. Taehwa, South Korea. We conducted numerical investigations into the impacts of(i) Shared Socioeconomic Pathways 2–4.5(SSP2-4.5) and 5–8.5(SSP5-8.5),(ii) elevated atmospheric CO_(2) and temperature, and(iii) acclimations of leaf area index and V_(cmax)on the carbon and water dynamics of P. koraiensis. We found that there was a reduction in net primary productivity(NPP) under the SSP2-4.5 scenario, but not under SSP5-8.5, compared to the baseline, due to an imbalance between increases in atmospheric CO_(2) and temperature. A decrease in leaf area index and an increase in V_(cmax)of P. koraiensis were expected if acclimations were made to reduce its leaf temperature. Under such acclimation pathways, it would be expected that the well-known CO_(2) fertilizer effects on NPP would be attenuated.

关键词： Climate change NEP Pinus koraiensis Warming Acclimation

Variability and trends of near-surface wind speed over the Tibetan Plateau:The role played by the westerly and Asian monsoon

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Advances in Climate Change Research 2024年第3期15卷 525-536页

作者： Gang-Feng ZHANG Cesar AZORIN-MOLINA Deliang CHEN Tim RMCVICAR Jose AGUIJARRO Kai-Qiang DENG Lorenzo MINOLA Jaeyeon LEE seok-woo SON Heng MA Pei-Jun SHI State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China Engineering Center of Desertification and Blown-Sand Control of Ministry of Education Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Key Laboratory of Environmental Change and Natural Disaster of Ministry of Education Beijing Normal UniversityBeijing 100875China Centro de Investigaciones Sobre Desertificaci'on Consejo Superior de Investigaciones Cientı'ficas(CIDECSIC-UV-Generalitat alenciana)ClimateAtmosphere and Ocean Laboratory(Climatoc-Lab)Moncada 46113Spain Regional Climate Group Department of Earth SciencesUniversity of GothenburgGothenburg 40530Sweden CSIRO Environment CanberraACT 2600Australia Australian Research Council Centre of Excellence for Climate Extremes CanberraACT 2600Australia State Meteorological Agency Balearic Islands OfficePalma de Mallorca 07015Spain School of Atmospheric Sciences Sun Yat-sen UniversityZhuhai 519082China Interuniversity Department of Regional and Urban Studies and Planning(DIST) Politecnico and University of TurinTurin 10125Italy School of Earth and Environmental Sciences Seoul National UniversitySeoul 08826South Korea Atmospheric and Oceanic Sciences Program Princeton UniversityPrinceton NJ 08544USA Geophysical Fluid Dynamics Laboratory NOAAPrinceton NJ 08544USA

Near-surface wind speed exerts profound impacts on many environmental issues,while the long-term(≥60 years)trend and multidecadal variability in the wind speed and its underlying causes in global high-elevation and mountainous areas(e.g.,Tibetan Plateau)remain largely ***,by examining homogenized wind speed data from 104 meteorological stations over the Tibetan Plateau for 1961-2020 and ERA5 reanalysis datasets,we investigated the variability and long-term trend in the near-surface wind speed and revealed the role played by the westerly and Asian *** results show that the homogenized annual wind speed displays a decreasing trend(-0.091 m s^(−1)per decade,p<0.05),with the strongest in spring(-0.131 m s^(−1)per decade,p<0.05),and the weakest in autumn(-0.071 m s^(−1)per decade,p<0.05).There is a distinct multidecadal variability of wind speed,which manifested in an prominent increase in 1961-1970,a sustained decrease in 1970-2002,and a consistent increase in *** observed decadal variations are likely linked to large-scale atmospheric circulation,and the correlation analysis unveiled a more important role of westerly and East Asian winter monsoon in modulating near-surface wind changes over the Tibetan *** potential physical processes associated with westerly and Asian monsoon changes are in concordance with wind speed change,in terms of overall weakened horizontal air flow(i.e.,geostrophic wind speed),declined vertical thermal and dynamic momentum transfer(i.e.,atmospheric stratification thermal instability and vertical wind shear),and varied Tibetan Plateau *** indicates that to varying degrees these processes may have contributed to the changes in near-surface wind speed over the Tibetan *** study has implications for wind power production and soil wind erosion prevention in the Tibetan Plateau.

关键词： Tibetan Plateau Wind speed Decadal change Atmospheric circulation Physical processes

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

In situ infrared, Raman and X-ray spectroscopy for the mechanistic understanding of hydrogen evolution reaction

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Journal of Energy Chemistry 2024年第3期90卷 632-651,I0014页

作者： Andi Haryanto Kyounghoon Jung Chan woo Lee Dong-Wan Kim Department of Chemistry Kookmin UniversitySeoul 02707Republic of Korea School of Civil Environmental and Architectural EngineeringKorea UniversitySeoul 02841Republic of Korea

Hydrogen production by water reduction reactions has received considerable attention because hydrogen is considered a clean-energy carrier,key for a sustainable energy *** methods have been widely used to study the reaction mechanism of the hydrogen evolution reaction(HER),but the calculation results need to be supported by experimental results and direct evidence to confirm the mechanistic *** this review,we discuss the fundamental principles of the in situ spectroscopic strategy and a theoretical model for a mechanistic understanding of the *** addition,we investigate recent studies by in situ Fourier transform infrared(FTIR),Raman spectroscopy,and X-ray absorption spectroscopy(XAS) and cover new findings that occur at the catalyst-electrolyte interface during *** spectroscopic strategies provide practical ways to elucidate catalyst phase,reaction intermediate,catalyst-electrolyte interface,intermediate binding energy,metal valency state,and coordination environment during HER.

关键词： Hydrogen evolution reaction Infrared spectroscopy Raman spectroscopy X-ray absorption spectroscopy Reaction mechanism

Comparative study between Embosphere®and Marine gel®as embolic agents for chemoembolization of hepatocellular carcinoma

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World Journal of Gastrointestinal Oncology 2024年第1期16卷 102-109页

作者： Hyo-Cheol Kim Jin woo Choi Department of Radiology Seoul National University HospitalSeoul 03080South Korea

BACKGROUND While gelatin sponge particles and calibrated microspheres are commonly used as embolic materials in conventional transarterial chemoembolization(cTACE),direct comparisons between these embolic agents are *** To compare the efficacy and safety of superselective cTACE using Embosphere®or Marine gel®in patients with early-stage hepatocellular carcinoma(HCC).METHODS This retrospective study included 70 patients with small(<4 cm)HCC who underwent cTACE with Embosphere®(n=33)or Marine gel®(n=37)as the embolic agent at a single center between March 2021 and July *** radiologic images and clinical data were retrospectively reviewed,with an emphasis on tumor response,procedure-related complications,and local tumor *** primary index tumor was assessed on a 1-mo follow-up image,and local progression-free survival was obtained using the Kaplan-Meier method and was compared by the log-rank *** The median tumor size of both groups was 1.5 cm,and 69 patients achieved a complete response one month after *** cumulative local recurrence rate at 12 mo was 15.5%in the Embosphere®group and 14.4%in the Marine gel®*** local progression-free survival was not significantly different between the two groups(P=0.83).In the multivariate analysis,high serum alphafetoprotein was the only significant poor prognostic factor for local tumor progression(P=0.01).Postembolization syndrome occurred in 36.4%of the Embosphere®group and 35.1%of the Marine gel®group,and there were no cases of biloma,biliary duct dilation,or liver abscess in either *** Calibrated gelatin sponge particles(Marine gel®)and calibrated microspheres(Embosphere®)have similar outcomes in terms of tumor response for superselective cTACE of small HCC.

关键词： Hepatocellular carcinoma Chemoembolization Temporary embolic material Permanent embolic material Tumor response