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Nano-Micro Letters 2022年第4期14卷 75-89页

作者： Il Gyu Jang Vignesh Murugadoss tae hoon Park Kyung Rock Son ho Jin lee WanQi Ren Min Ji Yu tae Geun Kim School of Electrical Engineering Korea UniversityAnam-ro 145Seongbuk-guSeoul 02841Republic of Korea

A novel device structure for thermally activated delayed fluorescence(TADF)top emission organic light-emitting diodes(TEOLEDs)that improves the viewing angle characteristics and reduces the efficiency roll-off is ***,we describe the design and fabrication of a cavity-suppressing electrode(CSE),Ag(12 nm)/WO_(3)(65 nm)/Ag(12 nm)that can be used as a transparent *** the TADF-TEOLED fabricated using the CSE exhibits higher external quantum efficiency(EQE)and improved angular dependency than the device fabricated using the microcavity-based Ag electrode,it suffers from low color purity and severe efficiency *** drawbacks can be reduced by using an optimized multi-quantum well emissive layer(MQW EML).The CSE-based TADF-TEOLED with an MQW EML fabricated herein exhibits a high EQE(18.05%),high color purity(full width at half maximum~59 nm),reduced efficiency roll-off(~46%at 1000 cd m^(−2)),and low angular *** improvements can be attributed to the synergistic effect of the CSE and MQW *** optimized transparent CSE improves charge injection and light outcoupling with low angular dependence,and the MQW EML effectively confines charges and excitons,thereby improving the color purity and EQE *** proposed approach facilitates the optimization of multiple output characteristics of TEOLEDs for future display applications.

关键词： Cavity suppression Multi-quantum well Viewing angle Efficiency roll-off Top emission OLED

A Study of the Vortical Flow over a Delta Wing with a Leading Edge Extension

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Journal of Thermal Science 2003年第4期12卷 299-303页

作者： Heuy-Dong Kim Young-Ki lee tae-ho Kim Myoung-Hwan Sohn School of Mechanical Engineering Andong National University Andong 760-749 KoreaSchool of Mechanical Engineering Andong National University Andong 760-749 KoreaSchool of Mechanical Engineering Andong National University Andong 760-749 KoreaDepartment of Aerospace Engineering Korean Air Force Academy Chongwon-gun ChungBook-Do 363-849 Korea

The present paper describes computational and experimental work on the vortex flow characteristics of a sharp-edged delta wing with a leading edge extension (LEX). Experiment was carried out using a low-speed wind tunnel that has a test section of 3.5 m(W)×2.45 m(H)×8.7 m(L). The angle of attack of the delta wing ranges from 10° to 30°. The free stream velocity is fixed at 20 m/s, which corresponds to Reynolds number of 0.88×106. Computations using the mass-averaged implicit 3D Navier-Stokes equations were applied to predict the complicated vortical flow over the delta wing. The governing equations were discretized in space using a fully implicit finite volume differencing formation. The standard k-e turbulent model was employed to close the governing equations. The present computations predicted the experimented flow field with a good accuracy.

关键词： delta wing leading edge extension (LEX) vortex core vortex strength.

Effect of silicon carbide-based iron catalyst on reactor optimization for non-oxidative direct conversion of methane

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Journal of Energy Chemistry 2023年第6期81卷 519-532,I0012页

作者： Eun-hae Sim Sung Woo lee Jin Ju lee Seung Ju Han Jung ho Shin Gracia lee Sungrok Ko Kwan-Young lee Yong tae Kim C1 Gas&Carbon Convergent Research Center Korea Research Institute of Chemical TechnologyDaejeon 34114Republic of Korea Department of Chemical and Biological Engineering Korea University145 Anam-roSeoul 02841Republic of Korea Department of Chemical and Biomolecular Engineering Yonsei University50 Yonsei-roSeoul 03722Republic of Korea Chemical Data-Driven Research Center Korea Research Institute of Chemical TechnologyDaejeon 34114Republic of Korea Prospective Tech.Exploring Section Basic Chemical R&D centerLottechemical Corp.Daejeon 34059Republic of Korea Department of Advanced Materials and Chemical Engineering University of Science and Technology(UST)Gajeong-dongYuseongDaejeon 34113Republic of Korea

The conversion of methane to olefins,aromatics,and hydrogen(MTOAH)can be used to stably obtain hydrocarbons when the effect of the catalytic surface is optimized from the reaction engineering *** this study,Fe/Si C catalysts were packed into a quartz tube *** catalytic surfaces of Si C and the impregnated Fe species decreased the apparent activation energies(E_a)of methane consumption in the blank reactor between 965 and 1020℃.Consequently,the hydrocarbon yield increased by 2.4times at 1020℃.Based on the model reactions of ethane,ethylene,and acetylene mixed with hydrogen in the range of 500-1020℃,an excess amount of Fe in the reactor favored the C-C coupling reaction over the selective hydrogenation of acetylene;consequently,coke formation was favored over the hydrogenation *** gas-phase reactions and catalyst properties were optimized to increase hydrocarbon yields while reducing coke *** 0.2Fe catalyst-packed reactor(0.26 wt%Fe)resulted in a hydrocarbon yield of 7.1%and a coke selectivity of<2%when the ratio of the void space of the postcatalyst zone to the catalyst space was adjusted to be≥*** on these findings,the facile approach of decoupling the reaction zone between the catalyst surface and the gas-phase reaction can provide insights into catalytic reactor design,thereby facilitating the scale-up from the laboratory to the commercial scale.

关键词： Non-oxidative methane conversion Ethylene Aromatic Methane pyrolysis Fe/SiC Coke resistance Catalytic reactor

Role of adjuvant chemotherapy on recurrence and survival in patients with resected ampulla of Vater carcinoma

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World Journal of Gastrointestinal Oncology 2023年第4期15卷 677-688页

作者： Se Jun Park Kabsoo Shin In-ho Kim tae ho hong Younghoon Kim Myung-ah lee Division of Medical Oncology Department of Internal MedicineThe Catholic University of KoreaSeoul St.Mary’s HospitalSeoul 06591South Korea Department of General Surgery The Catholic University of KoreaSeoul St.Mary’s HospitalSeoul 06591South Korea Department of Pathology The Catholic University of KoreaSeoul St.Mary’s HospitalSeoul 06591South Korea

BACKGROUND Owing to rarity of disease and lack of prospective studies, data supporting the role of adjuvant chemotherapy in ampulla of Vater(AoV) carcinoma is *** To evaluate whether adjuvant chemotherapy cases for AoV carcinoma had better disease-free survival(DFS) rates than cases of observation following curative *** We retrospectively analyzed the association between adjuvant chemotherapy and DFS and overall survival(OS) in patients with stage IB-Ⅲ AoV carcinoma who underwent curative surgical resection. Fluorouracil-based adjuvant chemotherapy was administered after surgery at the discretion of the physician. Adjusted multivariate regression models were used to evaluate the association between adjuvant chemotherapy and survival *** Of the total 104 patients who underwent curative surgery, 52 received adjuvant chemotherapy. Multivariate analysis revealed that higher histologic grade [hazard ratio(HR) = 2.24, P = 0.046], advanced tumor stage(HR = 1.85, P = 0.030), and vascular invasion(HR = 2.14, P = 0.010) were associated with shorter DFS. Adjuvant chemotherapy improved DFS compared to the observation group(HR =0.50, P = 0.015) and tended to be associated with a longer OS, although the difference was not statistically significant(HR = 0.58, P = 0.098).CONCLUSION Among patients with resected AoV carcinoma, the adjuvant chemotherapy group was not associated with a significant survival benefit compared to the observation group. however, on multivariate analysis adjusting for prognostic factors, adjuvant chemotherapy following surgery was an independent prognostic factor for DFS in patients with resected AoV carcinoma. Further studies are needed to investigate the effectiveness of adjuvant chemotherapy according to histologic phenotype.

关键词： Ampulla of Vater carcinoma Adjuvant chemotherapy Prognosis Recurrence

Porously Reduced 2-Dimensional Bi_(2)O_(2)CO_(3) Petals for Strain-Mediated Electrochemical CO_(2) Reduction to HCOOH

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Energy & Environmental Materials 2024年第1期7卷 215-221页

作者： Won Seok Cho Dae Myung hong Wan Jae Dong tae Hyung lee Chul Jong Yoo Donghwa lee ho Won Jang Jong-Lam lee Department of Materials Science and Engineering Pohang University of Science and Technology(POSTECH)Pohang Gyungbuk 37673Korea Department of Materials Science and Engineering Research Institute of Advanced Materials Seoul National UniversitySeoul 08826Korea

Here we introduce bismuth-based catalysts for the efficient electrochemical reduction of CO_(2)to formic acid(HCOOH),which are composed of petal-shaped Bi_(2)O_(2)CO_(3)(BOC)that spontaneously formed from Bi thin film in aqueous carbonate solution at room *** the electrochemical reduction process,the BOC petals transform to reduced BOC(R-BOC)consisting of individual BOC and Bi *** mismatch between both domains induces biaxial strain at the *** functional theory calculations suggest that the tensile strain on the Bi domain stabilizes the*OCho intermediate,reducing the thermodynamic barrier toward CO_(2)conversion to *** with the thermodynamic benefit and the unique nanoporous petal-shaped morphology,R-BOC petals have a superior Faradaic efficiency of 95.9%at-0.8 V_(RHE)for the electrochemical conversion of CO_(2)to *** work demonstrates that the spontaneously formed binary phases with desirable lattice strain can increase the activity of bismuth catalysts to the CO_(2)reduction reaction;such a strategy can be applicable in design of various electrocatalysts.

关键词： bismuth carbon dioxide reduction formic acid heterointerfaces strain

Phosphorylated p70S6K in urothelial carcinoma of the tumor recurrence noninvasive low-grade bladder： correlation with

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Asian Journal of Andrology 2014年第4期16卷 611-617页

作者： Soon-Ja Kim Jung hoon Kim Hui Seok Jung tae-Jin lee Kyung Mee lee In ho Chang Department of Convergence Medicine and Pharmaceutical Biosciences Chung-Ang University Graduate School Seoul Department of Urology Department of Pathology Chung-Ang University College of Medicine Seoul Korea.

We investigated whether inhibiting phosphorylated p70S6K （p-p70S6K） suppresses the proliferation and growth of noninvasive low-grade urothelial carcinoma （LG-URCa） in vitro and whether p-p70S6K can serve as a predictive biomarker for the recurrence of noninvasive LG-URCa of the bladder in patients. We constructed a tissue microarray （TMA） for 95 LG-URCa and 35 benign urothelium samples and performed immunohistochemical staining for p-p70S6K and p-4E-BP1. A Cox regression model was used to investigate the predictive factors for recurrence of LG-URCa. We investigated the dose-dependent antiproliferative effect of rapamycin, its antiproliferative effect and the growth-inhibition effect of p70S6K siRNA transfection in RT4 and 253J cell lines. The pT1 staged group （P 〈 0.05; hazard ratio （HR）, 2.415） and the high p-p70S6K staining group （P 〈 0.05; HR, 2.249） were independent factors for predicting recurrence. Rapamycin inhibited RT4 and 253J cell proliferation in a dose-dependent manner （r = -0.850, P 〈 0.001 in RT4 cells; r = -0.835, P 〈 0.001 in 253J cells）. RT4 and 253J cell proliferation and growth were inhibited by the transfection of p70S6K siRNA and rapamycin, respectively （P 〈 0.05）. Transfection of p70S6K siRNA resulted in inhibitory effects on cell proliferation and growth that were similar to those of rapamycin. Our results suggest that inhibiting p70S6K phosphorylation is important to prevent recurrence and that p70S6K phosphorylation can be used as a molecular biomarker to predict recurrence of certain LG-URCa of the bladder.

关键词： bladder cancer p7OS6K

Spectroscopic properties of Er3+/ho3+/Tm3+ doped α-SiAlON ceramics under 793 nm excitation

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Progress in Natural Science:Materials International 2021年第6期31卷 891-897页

作者： Bina Chaudhary Dhani Ram Dhakal tae-ho Kim Soo Wohn lee Yuwaraj K.Kshetri Department of Fusion Science and Technology Sun Moon University Research Center for Eco-Multifunctional Nano Materials Sun Moon University Department of Environment and Bio-Chemical Engineering Sun Moon University

This paper reports the first demonstration of super broadband infrared downshifting emission extending from1640 nm to 2200 nm with the full width at half maximum of ～ 417 nm in lanthanides(Er3+, ho3+, and Tm3+)-doped α-SiAlON ceramics upon 793 nm excitation. Using α-Si3N4ceramic as a precursor the lanthanides-dopedα-SiAlON ceramics were synthesized by the hot-press method. The lanthanides induced no significant secondary phases in the sintered α-SiAlON ceramics. Strong two-photon upconversion emission bands centered at 547,671 and 694 nm have also been observed upon 793 nm excitation. The time-resolved measurements of the upconversion emissions confirm that the efficient energy transfer among the Er3+, ho3+and Tm3+ions as well as the ground state absorption in Er3+and Tm3+are responsible for the observed spectroscopic properties.

关键词： α-SiAlON Upconversion Downshifting 793 nm excitation

Blue TiO2 polymorph: An efficient material for dye-sensitized solar cells fabricated using a low-temperature sintering process

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Progress in Natural Science:Materials International 2018年第5期28卷 548-553页

作者： Huy Hao Nguyen Gobinda Gyawali tae ho Kim Sami Bin Humam Soo Wohn lee Department of Environmental and Bio-chemical Engineering Sun Moon University Division of Basic Engineering Sun Moon University Division of Mechanics and ICT Convergence Engineering Sun Moon University

Recently,surface-disordered or non-stoichiometric TiO2,such as blue TiO2（B-TiO2）,has received much attention owing to its unique properties,such as structural disorder near the surface and the existence of Ti3+ions and oxygen ***,surface-disordered TiO2has been applied for microwave absorption,photocatalysis,in photoelectrochemical sensors and rechargeable lithium-ion *** this work B-TiO2,a polymorph consisting of nanoparticles,nanotubes and nanosheets,was successfully synthesized and employed as a semiconductor layer in dye-sensitized solar cells（DSSCs）fabricated using a low-temperature heat treatment process（120°C）.Based on the analyses of the experimental results regarding the structure and those from the characterization of B-TiO2,and its application to DSSCs,it has been found that the B-TiO2material has an effect on electron-hole pair *** conversion efficiency of the B-TiO2DSSC（BTiO2-DSSC）was 6.18%,whereas that of the TiO2-P25 DSSC（P25-DSSC）was 3.61%,and that of the TiO2polymorph DSSC（PTiO2-DSSC）which is the precursor of B-TiO2was 4.51%.

关键词： Surface-disordered TiO2 Blue TiO2 Dye-sensitized solar cell(DSSC) Oxygen vacancy Efficiency

Understanding the multifunctionality in Cu-doped BiVO_4 semiconductor photocatalyst

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Journal of Environmental Sciences 2019年第1期31卷 84-97页

作者： Chhabilal Regmi Yuwaraj K.Kshetri Ramesh Prasad PANDey tae-ho Kim Gobinda Gyawali Soo Wohn lee Department of Environmental and Biochemical Engineering Sun Moon University Department of Advanced Materials Engineering Sun Moon University Institute of Biomolecule Reconstruction Department of BT-Convergent Pharmaceutical Engineering Sun Moon University Division of Mechanics and ICT Convergence Engineering Sun Moon University

A visible light-induced, Cu-doped BiVO_4 photocatalyst was synthesized by a microwave hydrothermal method. The photocatalytic efficiency was investigated in the degradation of model water pollutants like Methylene Blue(dye) and ibuprofen(pharmaceuticals), as well as the inactivation of Escherichia coli(bacteria). The Cu-doped BiVO4 samples showed better efficiency than undoped BiVO_4, and the 1 wt.% Cu-doped BiVO_4 sample showed the best efficiency. The degradation of Methylene Blue reached 95%, while the degradation of ibuprofen reached 75%, and the inactivation of E. coli reached 85% in irradiation with visible light. The appearance of additional absorption band shoulders and widening of the optical absorption in the visible range makes the prepared powder an efficient visible light-driven photocatalyst. Moreover, the formation of an in-gap energy state just above the valance band as determined by density functional theory(DFT) first principle calculation, facilitates the wider optical absorption range of the doped system. Similarly, this in-gap energy state also acts as an electron trap, which is favorable for the efficient separation and photoexcited charge carriers' transfer process. The formation of oxygen vacancies due to doping also improved the separation of the charge carrier, which promoted the trapping of electrons and inhibited electron hole recombination, thus increasing the photocatalytic activity. No decrease in the efficiency of the 1 wt.% Cu-doped BiVO_4 photocatalyst in the degradation of ibuprofen over three consecutive cycles revealed the stability of the photocatalyst towards photocorrosion. These findings highlight the multifunctional applications of Cu-doped BiVO_4 in wastewater containing multiple pollutants.

关键词： BiVO4 Photocatalyst Methylene Blue Ibuprofen Escherichia coli First principle calculation

Cutting force signal pattern recognition using hybrid neural network in end milling

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中国有色金属学会会刊：英文版 2009年第B9期19卷 209-214页

作者： Song-tae SEONG Ko-tae JO Young-Moon lee Research and Development Department Gyeongbuk Hybrid Technology Institute School of Mechanical Engineering Yeongnam University School of Mechanical Engineering Kyungpo ok National University

Under certain cutting conditions in end milling, the signs of cutting forces change from positive to negative during a revolution of the tool. The change of force direction causes the cutting dynamics to be unstable which results in chatter vibration. Therefore, cutting force signal monitoring and classification are needed to determine the optimal cutting conditions and to improve the efficiency of cut. Artificial neural networks are powerful tools for solving highly complex and nonlinear problems. It can be divided into supervised and unsupervised learning machines based on the availability of a teacher. Hybrid neural network was introduced with both of functions of multilayer perceptron (MLP) trained with the back-propagation algorithm for monitoring and detecting abnormal state, and self organizing feature map (SOFM) for treating huge datum such as image processing and pattern recognition, for predicting and classifying cutting force signal patterns simultaneously. The validity of the results is verified with cutting experiments and simulation tests.

关键词：切削力信号混合神经网络模式识别铣床人工神经网络切削条件信号监测监督学习