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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第8期12卷 687-697页

作者： sun hee kim Hyung Jeong YANG Kam Swee NG Department of Computer Science Chonnam National University

Missing values occur in bio-signal processing for various reasons,including technical problems or biological *** missing values are then either simply excluded or substituted with estimated values for further *** the missing signal values are estimated for electroencephalography (EEG) signals,an example where electrical signals arrive quickly and successively,rapid processing of high-speed data is required for immediate decision *** this study,we propose an incremental expectation maximization principal component analysis (iEMPCA) method that automatically estimates missing values from multivariable EEG time series data without requiring a whole and complete data *** proposed method solves the problem of a biased model,which inevitably results from simply removing incomplete data rather than estimating them,and thus reduces the loss of information by incorporating missing values in real *** using an incremental approach,the proposed method alsominimizes memory usage and processing time of continuously arriving *** results show that the proposed method assigns more accurate missing values than previous methods.

关键词： Electroencephalography (EEG) Missing value imputation Hidden pattern discovery Expectation maximization Principal component analysis

Beta Gyres in Global Analysis Fields

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Advances in Atmospheric Sciences 2009年第5期26卷 984-994页

作者： sun-hee kim H. Joe KWON R. L. ELSBERRY Department of Atmospheric Sciences/Typhoon Research Center Kongju National University Department of Meteorology Naval Postgraduate School

A three-component decomposition is applied to global analysis data to show the existence of a beta gyre, which causes Tropical Cyclone （TC） to drift from a large-scale environmental steering current. Analyses from the Global Data Assimilation and Prediction System （GDAPS） of the Korea Meteorological Adminis- tration （KMA）, the Global Forecast System （GFS） of NCEP, and the Navy Operational Global Atmospheric Prediction System （NOGAPS） are used in this study. The structure of the beta gyre obtained in our analyses is in good agreement with the theoretical structure, with a cyclonic circulation to the southwest of the TC center, an anticyclonic circulation to the northeast, and a ventilation flow directed northwestward near the center. The circulation of the beta gyre is strongest at the 850-hPa level where the cyclonically swirling primary circulation is strongest, and decreases with height, in a pyramid shape similar to the primary circulation. The individual structure of the beta gyre is case- and model-dependent. At a certain analysis time, one model may clearly reveal a well-defined beta gyre, but the other models may not. Within one model, the beta gyre may be well defined at some analysis times, but not at other times. The structure of the beta gyre in the analysis field is determined by the nature of the vortex initialization scheme and the model behavior during the 6-h forecast in the operational data assimilation cycle.

关键词： tropical cyclone beta gyre GDAPS GFS NOGAPS TCM-90 final analyses

Mediating effect of work engagement between job characteristics and nursing performance among general hospital nurses

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Frontiers of Nursing 2021年第3期8卷 241-248页

作者： Eun-Kyung Lee sun-hee kim Jin-Hwa Park College of Nursing Research Institute of Nursing ScienceDaegu Catholic UniversityDaegu 42472South Korea

Objective:This study aimed to determine the effects of job characteristics and work engagement on the nursing performance of nurses working in general ***:Data were collected from 169 nurses who are working in a general hospital in South Korea by using a cross-sectional descriptive survey ***:Nurses’job characteristics and work engagement showed positive effects on nursing *** effect was magnified when work engagement was used as a mediating ***:The findings elucidate the factors influencing job performance and provide managers with important information for developing programs to improve the job skills and work engagement of nurses.

关键词： general hospitals job characteristics nurse work engagement work performance

Animal plant warfare and secondary metabolite evolution

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Natural Products and Bioprospecting 2013年第1期3卷 1-7页

作者： Steffen WÖLL sun hee kim Henry Johannes GRETEN Thomas EFFERTH Department of Pharmaceutical Biology Institute of Pharmacy and BiochemistryJohannes Gutenberg-UniversityMainzGermany Institute of Biomedical Sciences(ICBAS) University of PortoPortugal

The enduring discussion,why plants produce secondary metabolites with pharmacologically and toxicologically active towards mammals traces back to the eminent role of medicinal plants in the millennia-old history of *** recent years,the concept of an animal plant warfare emerged,which focused on the co-evolution between plants and *** a reaction to herbivory,plants developed mechanical defenses such as thorns and hard shells,which paved the way for adapted animal *** evolved further defense systems by producing chemicals that exert toxic effects on the animals that ingest *** a result of this selective pressure,animals developed special enzymes,*** P450 monooxigenases(CYP450)that metabolize xenobiotic *** a next step in the evolutionary competition between plants and animals,plants evolved to produce non-toxic pro-drugs,which become toxic only after ingestion by animals through metabolization by enzymes such as *** these sequestered evolutionary developments call to mind an arms race,the term animal plant warfare has been *** evolutionary competition between plants and animals may help to better understand the modes of action of medicinal plants and to foster the efficient and safe use of phytotherapy nowadays.

关键词： natural products phytochemicals liver metabolism cytochrome P450 monooxigenase ABC-transporter herbivore

Postmortem ^(7)Li NMR analysis for assessing the reversibility of lithium metal electrodes in lithium metal batteries

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Journal of Energy Chemistry 2024年第7期94卷 430-440页

作者： Jaewon Baek sunha kim hee-Tak kim Oc hee Han Department of Chemical&Biomolecular Engineering KAISTDaejeon 34141Republic of Korea Metropolitan Seoul Center Korea Basic Science InstituteSeoul 03759Republic of Korea Graduate School of Analytical Science&Technology Chungnam National UniversityDaejeon 34134Republic of Korea

Despite the proficiency of lithium(Li)-7 NMR spectroscopy in delineating the physical and chemical states of Li metal electrodes,challenges in specimen preparation and interpretation impede its *** this study,we conducted a comprehensive postmortem analysis utilizing ^(7)Li NMR,employing a stan-dard magic angle spinning probe to examine protective-layer coated Li metal electrodes and LiAg alloy electrodes against bare Li metal electrodes within Li metal batteries(LMBs).Our investigation explores the effects of sample burrs,alignment with the magnetic field,the existence of liquid electrolytes,and precycling on the ^(7)Li NMR *** contrasting NMR spectra before and after cycling,we identi-fied alterations in Li^(0) and Li^(+) signals attributable to the degradation of the Li metal *** NMR analyses decisively demonstrate the efficacy of the protective layer in mitigating dendrite and solid elec-trolyte interphase ***,we noted that Li*ions near the Li metal surface exhibit magnetic susceptibility anisotropy,revealing a novel approach to studying diamagnetic species on Li metal elec-trodes in *** study provides valuable insights and practical guidelines for characterizing distinct lithium states within LMBs.

关键词： NMR spectroscopy Lithium-7 Lithium metal battery Electrolyte Electrode-protective layer Solid electrolyte interface Magnetic susceptibility anisotropy Lithium-metal NMR signal Diamagnetic^(7)Li NMR signal

Correlation between hydration properties and electrochemical performances on Ln cation size effect in layered perovskite for protonic ceramic fuel cells

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Journal of Energy Chemistry 2024年第1期88卷 1-9,I0001页

作者： Inhyeok Cho Jiwon Yun Boseok Seong Junseok kim sun hee Choi Ho-Il Ji Sihyuk Choi Department of Mechanical Engineering Kumoh National Institute of TechnologyGumi 39177GyeongbukRepublic of Korea Department of Aeronautics Mechanical and Electronic Convergence EngineeringKumoh National Institute of TechnologyGumi 39177GyeongbukRepublic of Korea Center for Energy Materials Research Korea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Center for Hydrogen and Fuel Cell Research Clean Technology Research DivisionKorea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Department of Energy and Environmental Engineering University of Science and TechnologySeoul 02792Republic of Korea Nanomaterials Science and Engineering Korea University of Science and Technology(UST)KIST CampusSeoul 02792Republic of Korea

PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.

关键词： Protonic ceramic fuel cell Cathode Triple ionic and electronic conductor Hydration property Proton uptake Gibbs free energy

Insights into the changes in the surface properties of goethite with Ni in the lattice in the presence of salicylhydroxamic acid:Experimental and density functional theory studies

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 665-677页

作者： Levie Mweene Gilsang Hong hee-Eun Jeong hee-won Kang Hyunjung kim Department of Earth Resources and Environmental Engineering Hanyang University222 Wangsimni-roSeongdong-guSeoul 04763Republic of Korea

Comparative experiments and theoretical analysis of the surface chemistry changes of goethite(GT)and goethite containing Ni(GTN)in the lattice in the presence of salicylhydroxamic acid(SA)were *** was revealed that in the presence of 100 g·t^(-1)of SA,the flotation recovery of GTN and GT increased with increasing pH,achieving a maximum recovery of 98.9%for both minerals at p H 8.3 and decreasing beyond that pH,with GTN having a slightly higher recovery than GT,except at pH *** was further confirmed by the higher complexation energies of GTN···SA(-883.87 kJ·mol^(-1))compared with GT···SA(-604.23 kJ·mol^(-1))resulting from covalent,closed-shell,and conventional hydrogen *** higher adsorption of SA onto GTN relative to GT was due to the formation of aπ-hole in GTN,thereby promoting a higher interaction of the collector with the ***,the presence of Ni in the GT lattice improves and decreases the adsorption and desorption of SA onto and from the mineral,respectively,compared with those onto and from GT.

关键词： nickel goethite adsorption salicylhydroxamic acid recovery

Development and application of a multi-step porcine in vitro system to evaluate feedstuffs and feed additives for their efficacy in nutrient digestion, digesta characteristics, and intestinal immune responses

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Animal Nutrition 2024年第2期17卷 265-282页

作者： hee Yeon kim Jun-Ok Moon sung Woo kim Application Center CJ Blossom Park Department of Animal Science North Carolina State University

In vitro model provides alternatives to the use of live animals in research. In pig nutrition, there has been a tremendous increase in in vivo research over the decades. Proper utilization of in vitro models could provide a screening tool to reduce the needs of in vivo studies, research duration, cost, and the use of animals and feeds. This study aimed to develop a multi-step porcine in vitro system to simulate nutrient digestion and intestinal epithelial immune responses affected by feedstuffs and feed additives. Seven feedstuffs(corn, corn distillers dried grains with solubles [corn DDGS], barley, wheat, soybean meal, soy protein concentrates, and Corynebacterium glutamicum cell mass [CGCM]), feed enzymes(xylanase and phytase), and supplemental amino acids(arginine, methionine, and tryptophan), were used in this in vitro evaluation for their efficacy on digestibility, digesta characteristics, and intestinal health compared with the results from previously published in vivo studies. All in vitro evaluations were triplicated. Data were analyzed using Mixed procedure of SAS9.4. Evaluations included(1) nutrient digestibility of feedstuffs,(2) the effects of feed enzymes, xylanase and phytase, on digestibility of feedstuffs and specific substrates, and(3) the effects of amino acids, arginine, tryptophan, and methionine, on anti-inflammatory, anti-oxidative, and anti-heat stress statuses showing their effects(P < 0.05) on the measured items. Differences in dry matter and crude protein digestibility among the feedstuffs as well as effects of xylanase and phytase were detected(P < 0.05), including xylo-oligosaccharide profiles and phosphorus release from phytate. Supplementation of arginine, tryptophan, and methionine modulated(P < 0.05) cellular inflammatory and oxidative stress responses. The use of this in vitro model allowed the use of 3 experimental replications providing sufficient statistical power at P < 0.05. This indicates in vitro models can have increased prec

关键词： Digestion Feed additive Feedstuff In vitro Intestine Pig

Investigations on Structural Safety of Office Room Based on Fire Simulation and Transient Heat Transfer Analysis

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World Journal of Engineering and Technology 2014年第3期2卷 20-26页

作者： Ah Young An Eun Mi Ryu hee sun kim Department of Architectural Engineering Ewha Woman’s University Seoul Korea

This study aims at investigating heat propagations inside the structural members due to fire using fire simulation and transient heat transfer analysis. Toward that goal, fire simulation and transient heat transfer analysis for a 5-story building are carried out sequentially using Fire Dynamics Simulator (FDS) and ABAQUS 6.10-3, respectively. As results from fire simulation, temporal temperature information is obtained depending on various locations of the building, which is used as boundary condition for the structural elements generated in transient heat transfer analysis. Predictions from the transient heat transfer analysis show that the structural members are exposed spatially non-uniform temperatures which can cause significant eccentric deformation and aceleration of structural damages.

关键词： Fire Simulation Heat Transfer Structural Safety Fire

Flexible thermocouple using a thermoelectric graphene fiber with a seamless junction

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Journal of Materials Science & Technology 2024年第5期172卷 15-22页

作者： Seungwon kim Soomook Lim Myeong hee Jeong Wonjoon kim Seunghyun Baik Ji Won Suk School of Mechanical Engineering Sungkyunkwan UniversitySuwonGyeonggi-do 16419Republic of Korea Department of Smart Fab.Technology Sungkyunkwan UniversitySuwonGyeonggi-do 16419Republic of Korea SKKU Advanced Institute of Nanotechnology(SAINT) Sungkyunkwan UniversitySuwonGyeonggi-do 16419Republic of Korea

Temperature is an important physical variable that indicates the condition of the human body and artificial *** wearable applications require the development of temperature sensors with different form *** this study,a fiber-shaped thermoelectric temperature sensor is fabricated using a continuous graphene fiber whose two halves possess different reduction states.A seamless junction is formed by partially reducing a wet-spun graphene oxide fiber with hydroiodic acid(HI)solutions of different ***-half of the fiber is mildly reduced with 0.97 wt%HI,while the other half is highly reduced with 30.6 wt%*** different reduction states of the graphene composite fiber result in different Seebeck coefficients,allowing for the fabrication of a fiber-shaped graphene thermocou-ple without any laborious *** flexible graphene thermocouple exhibits high sensitivity with a thermopower of 12.5μV K^(-1)in the temperature range of room temperature to∼70℃.Furthermore,it exhibits high linearity with a correlation coefficient exceeding 0.995 and fast response with a time constant of 0.24 *** to its mechanical robustness and flexibility,the stand-alone graphene ther-mocouple can be knitted into a cotton fabric glove,which presents a fast response to environmental changes without any external power *** work offers a unique fabrication method for producing a high-performance,flexible thermocouple that features a seamless and clear junction without the use of additional *** alternative method eliminates the complicated assembly processes typically required for conventional thermocouples.

关键词： Graphene fiber Thermocouple Reduced graphene oxide Flexible temperature sensor Seebeck coefficient