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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 Depar.ment 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

Enhancing ammonia production rates from electrochemical nitrogen reduction by engineering three-phase boundary with phosphorus-activated Cu catalysts

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Journal of Energy Chemistry 2023年第9期84卷 394-401页

作者： Jeehye Kim Cho hee Lee Yong Hyun Moon Min hee Lee Eun Hyup Kim sun hee Choi Youn Jeong Jang Jae sung Lee School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology(UNIST)Ulsan 44919Republic of Korea Depar.ment of Chemical Engineering Hanyang UniversitySeoul 04763Republic of Korea Pohang Accelerator Laboratory(PAL) Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea

Electrochemical N_(2) reduction reaction(eNRR) over Cu-based catalysts suffers from an intrinsically low activity of Cu for activation of stable N_(2) molecules and the limited supply of N_(2) to the catalyst due to its low solubility in aqueous ***,we propose phosphorus-activated Cu electrocatalysts to generate electron-deficient Cu sites on the catalyst surface to promote the adsorption of N_(2) *** eNRR system is further modified using a gas diffusion electrode(GDE) coated with polytetrafluoroethylene(PTFE) to form an effective three-phase boundary of liquid water-gas N_(2)-solid catalyst to facilitate easy access of N_(2) to the catalytic *** a result,the new catalyst in the flow-type cell records a Faradaic efficiency of 13.15% and an NH_(3) production rate of 7.69 μg h^(-1) cm^(-2) at-0.2 V_(RHE),which represent 3.56 and 59.2 times increases from those obtained with a pristine Cu electrode in a typical electrolytic *** work represents a successful demonstration of dual modification strategies;catalyst modification and N_(2) supplying system engineering,and the results would provide a useful platform for further developments of electrocatalysts and reaction systems.

关键词： Electrochemical nitrogen reduction reaction Ammonia production Phosphorous modified copper electrodes Gas diffusion electrodes Three-phase boundary PTFE coating

A density functional theory study of the tunable structure, magnetism and metal-insulator phase transition in VS2 monolayers induced by in-plane biaxial strain

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Nano Research 2015年第4期8卷 1348-1356页

作者： Min Kan Bo Wang Young hee Lee Qiang sun Depar.ment of Materials Science and Engineering Peking University 8eijing 100871 China Center for Integrated Nanostructure Physics Institute for Basic Science Sungkyunkwan University Suwon 440-746 Korea Depar.ment of Physics and Depar.ment of Energy Science Sungkyunkwan University Suwon 440-746 Korea School of Mathematical Sciences Peking University Beijing 100871 China Center forAppfied Physics and Technology Peking University Beijing 100871 China

We report a density functional theory study of a phase transition of a VS2 monolayer that can be tuned by the in-plane biaxial strain. This results in both a metal-insulator transition and a low spin-high spin magnetic transition. At low temperature, the semiconducting H-phase is stable and large strain （〉3%） is required to provoke the transition. On the other hand, at room temperature （300 K）, only a small tensile strain of 2% is needed to induce the phase transition from the semiconducting H-phase to the metallic T-phase together with the magnetic transition from high spin to low spin. The phase diagram dependence on both strain and temperature is also discussed in order to provide a better understanding of the phase stability of VS2 monolayers.

关键词： phase transition biaxial strain phase diagram density functional theory(DFT) transition metaldichalcogenide(TMD) materials

Compar.tive analyses of the venom components in the salivary gland transcriptomes and saliva proteomes of some heteropteran insects

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Insect Science 2022年第2期29卷 411-429页

作者： Kyungjae Andrew Yoon Woo-Jin Kim Seungki Lee hee-sun Yang Byoung-hee Lee Si Hyeock Lee Research Institute of Agriculture and Life Sciences Seoul National UniversitySeoulKorea EntoCode Co. SeoulKorea National Institute of Biological Resources Environmental Research ComplexIncheonKorea Depar.ment of Agricultural Biology Seoul National UniversitySeoulKorea

Salivary gland-specific transcriptomes of nine heteropteran insects with distinct feeding strategies (predaceous, hematophagous, and phytophagous) were analyzed and annotated to compar. and identify the venom components as well as their expression profiles. The transcriptional abundance of venom genes was verified via quantitative real-time PCR. Hierarchical clustering of 30 representative differentially expressed venom genes from the nine heteropteran species revealed unique groups of salivary gland-specific genes depending on their feeding strategy. The commonly transcribed genes included a par.lytic neurotoxin (arginine kinase), digestive enzymes (cathepsin and serine protease), an anti-inflammatory protein (cystatin), hexamerin, and an odorant binding protein. Both predaceous and hematophagous (bed bug) heteropteran species showed relatively higher transcription levels of genes encoding proteins involved in proteolysis and cytolysis, whereas phytophagous heteropterans exhibited little or no expression of these genes, but had a high expression of vitellogenin, a multifunctional allergen. Saliva proteomes from four representative species were also analyzed. All venom proteins identified via saliva proteome analysis were annotated using salivary gland transcriptome data. The proteomic expression profiles of venom proteins were in good agreement with the salivary gland-specific transcriptomic profiles. Our results indicate that profiling of the salivary gland transcriptome provides important information on the composition and evolutionary features of venoms depending on their feeding strategy.

关键词： hematophagous heteroptera phytophagous predaceous proteome analysis salivary gland-specific venom transcriptome analysis

Detection of stacking orientation error of CFRP composite laminates using ultrasound waves

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中国有色金属学会会刊：英文版 2009年第B9期19卷 124-127页

作者： sun-Kyu KIM David HSU Young-Hwan SEO Kwang-hee IM Division of Mechanical System Engineering Chonbuk National University Center for Nondestructive Evaluation Iowa State University Depar.ment of Physical Education Chosun University Depar.ment of Automotive Engineering Woosuk University

A jig was developed for generating a shear wave. A pyramid with an isosceles triangle with two 45o was made of aluminum to generate shear waves using two longitudinal transducers based on ultrasonic-polarized mechanism. Also, the signal splitter was connected to the pulser jack on the pulser/receiver and to the longitudinal transducers. Therefore, an experimental way was performed in order to make shear wave on the bottom of aluminum alloyed pyramid. Also, a jig was manufactured and developed for generating a shear wave based on the computer numerical simulation. It is found that the experimentally shear wave variation of newly-designed jig is consistent with computer numerical simulation results and shear wave ultrasonic application can be very useful to detect the defects in CFRP composites.

关键词：碳纤维复合材料误差检测超声波复合材料层板计算机数值模拟堆垛脉冲发生器信号分配器

Cloud Radiative Effects and Changes Simulated by the Coupled Model Intercompar.son Project Phase 5 Models

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Advances in Atmospheric Sciences 2017年第7期34卷 859-876页

作者： sun-hee SHIN Ok-Yeon KIM Dongmin KIM Myong-In LEE Climate Research Depar.ment APEC Climate Center Busan 48058 Republic of Korea School of Urban and Environmental Engineering Ulsan National Institute of Science and Technology Ulsan 44919 Republic of Korea

Using 32 CMIP5（Coupled Model Intercompar.son Project Phase 5） models, this study examines the veracity in the simulation of cloud amount and their radiative effects（CREs） in the historical run driven by observed external radiative forcing for 1850-2005, and their future changes in the RCP（Representative Concentration Pathway） 4.5 scenario runs for2006-2100. Validation metrics for the historical run are designed to examine the accuracy in the representation of spatial patterns for climatological mean, and annual and interannual variations of clouds and CREs. The models show large spread in the simulation of cloud amounts, specifically in the low cloud amount. The observed relationship between cloud amount and the controlling large-scale environment are also reproduced diversely by various models. Based on the validation metrics,four models-ACCESS1.0, ACCESS1.3, Had GEM2-CC, and Had GEM2-ES-are selected as best models, and the average of the four models performs more skillfully than the multimodel ensemble *** models project global-mean SST warming at the increase of the greenhouse gases, but the magnitude varies across the simulations between 1 and 2 K, which is largely attributable to the difference in the change of cloud amount and distribution. The models that simulate more SST warming show a greater increase in the net CRE due to reduced low cloud and increased incoming shortwave radiation, par.icularly over the regions of marine boundary layer in the subtropics. Selected best-performing models project a significant reduction in global-mean cloud amount of about-0.99% K^-1and net radiative warming of 0.46 W m^-2K^-1, suggesting a role of positive feedback to global warming.

关键词： warming cloud radiative historical CMIP interannual greenhouse ACCESS oceans seasonal

Korean red ginseng promotes hippocampal neurogenesis in mice

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Neural Regeneration Research 2020年第5期15卷 887-893页

作者： sun Ryu Hyongjun Jeon hee-Young Kim sungtae Koo Seungtae Kim Korean Medicine Research Center for Healthy Aging Pusan National University49 Busandaehak-roMulgeum-eupYangsan-siGyeongsangnam-do 50612Republic of Korea Depar.ment of Korean Medical Science School of Korean MedicinePusan National University49 Busandaehak-roMulgeum-eupYangsan-siGyeongsangnam-do 50612Republic of Korea

Neurogenesis in the adult hippocampus plays a major role in cognitive ability of animals including learning and *** red ginseng (KRG) has long been known as a medicinal herb with the potential to improve learning and memory;however,the mechanisms are still ***,we evaluated whether KRG can promote cognitive function and enhance neurogenesis in the ***-week-old male C57BL/6 mice received 50 mg/kg of 5-bromo-2′-deoxyuridine (BrdU) intraperitoneally and 100 mg/kg of KRG or vehicle orally once a day for 14 ***,Rotarod and Morris water maze tests were performed and the brains were collected after the last behavioral *** in the numbers of BrdU- and BrdU/ doublecortin (DCX;a marker for neuronal precursor cells and immature neurons)-positive cells in the dentate gyrus and the gene expression of proliferating cell nuclear antigen (a marker for cell differentiation),cerebral dopamine neurotrophic factor and ciliary neurotrophic factor in the hippocampus were then ***-treated mice came down the pole significantly faster and stood on the rotarod longer than vehicle-treated *** Morris water maze test showed that KRG administration enhanced the learning and memory abilities *** also significantly increased BrdU- and BrdU/DCX-positive cells in the dentate gyrus as well as the proliferating cell nuclear antigen,cerebral dopamine neurotrophic factor and ciliary neurotrophic factor mRNA expression levels in the hippocampus compar.d to *** of KRG promotes learning and memory abilities,possibly by enhancing hippocampal *** study was approved by the Pusan National University Institutional Animal Care and Use Committee (approval ***-2016-1071) on January 19,2016.

关键词： bromodeoxyuridine cerebral dopamine neurotrophic factor ciliary neurotrophic factor doublecortin ginseng hippocampus Korean red ginseng learning memory neurogenesis proliferating cell nuclear antigen red ginseng

Fabrication of Polythiophene Patterns through Blending of a Thermally Curable Polythiophene with Poly(methyl methacrylate) and Selective Thermal Curation

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Chinese Journal of Polymer Science 2017年第3期35卷 422-433页

作者： Mushtaque A.Memon Jin-hua sun hee-Tae Jung 闫寿科耿建新 State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 China National Research Laboratory Department of Chemical and Biomolecular Engineering (BK-21) Korea Advanced Institute of Science and Technology 373-1 Guseong-dong Yuseong-gu Daejeon 305-701 Korea

In this study, we demonstrate a novel method for fabricating polythiophene patterns, i.e., cylindrical holes and cylinders, through blending of a thermally curable polythiophene carrying with tertiary ester groups(PT-tert-ESTER) and poly(methyl methacrylate)(PMMA), followed by thermal conversion of the PT-tert-ESTER to an insoluble polythiophene via low-temperature cleavage of the tertiary ester groups and removal of the PMMA component via ultraviolet degradation. We show that the surface polarity of substrates, the mass ratio of PT-tert-ESTER to PMMA in the blend solutions as well as the concentration of the blend solutions strongly influence the formation of the polythiophene patterns. Cylindrical holes are more readily formed on less polar substrates when a PT-tert-ESTER dominated blend solution is used, while cylinders are more readily formed on more polar substrates when a PMMA dominated blend solution is used. Moreover, the diameters of both the cylindrical holes and the cylinders decrease as the PT-tert-ESTER concentration is increased in the respective ranges of the PT-tert-ESTER/PMMA ratios where the patterns are formed. Grazing incident X-ray diffraction data have indicated that the patterning of the PT-tert-ESTER component in the blend films improves the crystallinity of PT-tert-ESTER as well as the molecular packing of the insoluble polythiophene in the resultant patterned polythiophene films.

关键词： Polythiophene Patterns Cylindrical holes Cylinders Blending

Symmetrically dispersed spectroscopic singlemolecule localization microscopy

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Light(Science & Applications) 2020年第1期9卷 1154-1163页

作者： Ki-hee Song Yang Zhang Benjamin Brenner Cheng sun Hao F.Zhang Depar.ment of Biomedical Engineering Northwestern University2145 Sheridan Rd.EvanstonIL 60208USA Depar.ment of Mechanical Engineering Northwestern University2145

Spectroscopic single-molecule localization microscopy(sSMLM)was used to achieve simultaneous imaging and spectral analysis of single molecules for the first *** sSMLM fundamentally suffers from a reduced photon budget because the photons from individual stochastic emissions are divided into spatial and spectral ***,both spatial localization and spectral analysis only use a portion of the total photons,leading to reduced precisions in both *** improve the spatial and spectral precisions,we present symmetrically dispersed sSMLM,or SDsSMLM,to fully utilize all photons from individual stochastic emissions in both spatial and spectral *** achieved 10-nm spatial and 0.8-nm spectral precisions at a total photon budget of *** with the existing sSMLM using a 1:3 splitting ratio between spatial and spectral channels,SDsSMLM improved the spatial and spectral precisions by 42% and 10%,respectively,under the same photon *** also demonstrated multicolour imaging of fixed cells and three-dimensional single-par.icle tracking using *** enables more precise spectroscopic single-molecule analysis in broader cell biology and material science applications.

关键词： dispersed spectroscopic stochastic

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 Depar.ment of Atmospheric Sciences/Typhoon Research Center Kongju National University Depar.ment 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