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2D spinel ZnCo_(2)O_(4) microsheet-coated functional separator for promoted redox kinetics and inhibited polysulfide dissolution

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Journal of Energy Chemistry 2021年第4期30卷 468-475页

作者： Jeong Seok Yeon tae Ho park Young Hun Ko Periyasamy Sivakumar Jun Su Kim Youngkywon Kim Ho Seok park School of Chemical Engineering Sungkyunkwan UniversitySuwon 16419Gyeonggi-doRepublic of Korea Advanced Batteries Research Center Korea Electronics Technology InstituteSeongnam 13509Gyeonggi-doRepublic of Korea Department of Health Sciences and Technology Samsung Advanced Institute for Health Sciences and Technology(SAIHST)Sungkyunkwan UniversitySuwon 16419Gyeonggi-doRepublic of Korea Department of Chemistry Dongguk University-Seoul CampusJung-gu 04620 SeoulRepublic of Korea

Lithium-sulfur(Li-S)batteries are receiving increasing attention as one of the potential next-generation batteries,owing to their high energy densities and low ***,practical Li-S batteries with high energy densities are extremely hindered by the sulfur loss,low Coulombic efficiency,and short cycling life originating from the polysulfide(LiPS)*** this study,two-dimensional(2D)ZnCo_(2)O_(4) microsheets fabricated by a facile hydrothermal process are employed to modify the separator,for improving the electrochemical performances of Li-S *** resulting 2D Zn Co_(2)O_(4)-coated separator features a coating thickness of approximately 10 lm,high ionic conductivity of 1.8 m S/cm,and low mass loading of 0.2 mg/cm^(2).This 2D ZnCo_(2)O_(4)-coated separator effectively inhibits Li PS shuttle by a strong chemical interaction with Li PS as well as promotes the redox kinetics by Zn CO2O4-coated layers,as determined by X-ray photoelectron spectroscopy analysis,self-discharge,time-dependent permeation test,Li symmetric cell test,and Li2S nucleation ***,the Li-S batteries based on the 2D Zn Co_(2)O_(4)-coated separator exhibit a high initial discharge capacity of 1292.2 m Ah/g at 0.1 ***,they exhibit excellent long cycle stability at 1 and 2 C with capacity retention of 84%and 86%even after800 cycles,corresponding to a capacity fading rate of 0.020%and 0.016%per cycle,***,these Li-S cells with a high sulfur loading at 5.3 mg/cm^(2) and low electrolyte concentration of 9 l L/mg deliver a high discharge capacity of 4.99 m Ah/cm^(2) after 200 cycles at 0.1 C.

关键词： Lithium sulfur batteries Functional separator 2D microsheet Polysulfide Redox kinetics

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Endoscopic bilateral stent-in-stent placement for malignant hilar obstruction using a large cell type stent

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Hepatobiliary & Pancreatic Diseases International 2016年第6期15卷 633-639页

作者： jin Myung park Sang Hyub Lee Kwang Hyun Chung Dong Kee Jang ji Kon Ryu Yong-tae Kim Jae Min Lee Woo Hyun Paik Department of Internal Medicine and Liver Research Institute Seoul National University HospitalSeoul National University College of Medicine Department of Internal Medicine Kangwon National University HospitalKangwon National University School of Medicine Department of Internal Medicine Gyeongsang National University HospitalGyeongsang National University College of Medicine Department of Internal Medicine Inje University Ilsan Paik Hospital

BACKGROUND： Bilateral stent-in-stent （SIS） self-expandable metal stent placement is technically chghallenging for palliation of unresectable malignant hilar obstruction. In the SIS technique, the uniform large cell type biliary stent facilitates contralateral stent deployment through the mesh of the first metallic stent. This study aimed to assess the technical success and clinical effectiveness of this technique with a uniform large cell type biliary stent. METHODS： Thirty-one patients who underwentlbilateral SIS placement using a large cell type stent were reviewed retrospectively. All patients showed malignant hilarl obstruction （Bismuth types Ⅱ, Ⅲ, Ⅳ） with different etiologies. RESULTS： Sixteen （51.6%） patients were male. The mean age of the patients was 67.0±14.0 years. Most patients were diagnosed as having hilar cholangiocarcinoma （58.1%） and gallbladder cancer （29.0%）. Technical success rate was 83.9%. Success was achieved more frequently in patients without masses obstructing the biliary confluence （MOC） than those with MOC （95.2% vs 60.0%, P=0.03）. Functional success rate was 77.4%. Complications occurred in 29.0% of the patients. These tended to occur more frequently in patients with MOC （50.0% vs 19.0%, P=0.11）. Median time to recurrent biliary obstruction was 188 days and median survival was 175 days. CONCLUSIONS： The large cell type stent can be used efficiently for bilateral SIS placement in malignant hilar obstruction. However, the risk of technical failure increases in patients with MOC, and caution is needed to prevent complications for these patients.

关键词： biliary tract disease cholangiocarcinoma endoscopic biliary drainage stent insertion

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Antiviral efficacy of adefovir dipivoxil versus lamivudine in patients with chronic hepatitis B sequentially treated with lamivudine and adefovir due to lamivudine resistance

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World Journal of Gastroenterology 2007年第30期13卷 4072-4079页

作者： Yeon Seok Seo ji Hoon Kim Jong Eun Yeon Jong-Jae park Jae Seon Kim Kwan Soo Byun Young-tae Bak Chang Hong Lee Division of Gastroenterology and Hepatology Department of Internal Medicine Korea University College of Medicine Seoul Korea Division of Gastroenterology and Hepatology Department of Internal Medicine Konkuk University College of Medicine Seoul Korea

AIM： To compare the antiviral efficacy of adefovir （ADV） in lamivudine （LMV）-resistant patients with LMV treatment in nucleoside-naive patients, using serum samples collected sequentially during the course of treatment progressing from LMV to ADV.METHODS： Forty-four patients with chronic hepatitis B （CHB） were included. The patients were initially treated with LMV and then switched to ADV when LMV resistance developed. Antiviral efficacy was assessed by measuring the following： reduction in serum HBV DNA from baseline, HBV DNA negative conversion （defined as HBV DNA being undectable by the hybridization assay）, and HBV DNA response （either HBV DNA level ≤ 10^s copies/mL or a ≥ 2 log10 reduction from baseline HBV DNA level）.RESULTS： After two and six months of treatment, HBV DNA reduction was greater with LMV compared to ADV treatment （P = 0.021）. HBV DNA negative conversion rates were 64% and 27% after one month of LMV and ADV treatment respectively （P = 0.001）. Similarly, HBV DNA response rates were 74% and 51% after two months of LMV and ADV treatment respectively （P = 0.026）. The time taken to HBV DNA negative conversion and to HBV DNA response were both delayed in ADV treatment compared with LMV.CONCLUSION： The antiviral efficacy of ADV in LMV-resistant patients is slower and less potent than that with LMV in nucleoside-naive patients during the early course of treatment.

关键词： Chronic hepatitis B Lamivudine Adefovir Treatment efficacy

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Risk factors of organ failure in cholangitis with bacteriobilia

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World Journal of Gastroenterology 2015年第24期21卷 7506-7513页

作者： Jae Min Lee Sang Hyub Lee Kwang Hyun Chung jin Myung park Ban Seok Lee Woo Hyun Paik Joo Kyung park ji Kon Ryu Yong-tae Kim Departments of Internal Medicine and Liver Research Institute Seoul National University College of Medicine Seoul National University Hospital Department of Internal Medicine Gyeongsang National University College of Medicine Gyeongsang National University Hospital Department of Internal Medicine Kangwon National University School of Medicine Kangwon National University Hospital Department of Internal Medicine Inje University Ilsan Paik Hospital Department of Gastroenterology Department of Medicine Samsung Medical Center Sungkyunkwan University School of Medicine

AIM: To identify the risk factors for organ failure(OF) in cholangitis with ***: This study included 182 patients with acute cholangitis who underwent percutaneous transhepatic biliary drainage between January 2005 and April 2013. We conducted a retrospective analysis of comprehensive clinical and laboratory ***: There were 24 cases(13.2%) of OF and five deaths(2.7%). Bile culture was positive for microbial growth in 130 out of 138(94.2%) patients. In multivariate analysis of 130 patients with positivebile cultures, significant predictive factors for OF were the presence of extended-spectrum beta-lactamase(ESBL) organisms in blood cultures, pre-existing renal dysfunction, and choledocholithiasis as an etiology, with odds ratios of 15.376, 6.319, and 3.573, respectively. We developed a scoring system with a regression coefficient of each significant variable. The OF score was calculated using the following equation:(2.7 × ESBL organisms in blood cultures) +(1.8 × pre-existing renal dysfunction) +(1.3 × choledocholithiasis). This scoring system for predicting OF was highly specific(99.1%) and had a positive predictive value of 86.2%.CONCLUSION: ESBL organisms in blood cultures, preexisting renal dysfunction, and choledocholithiasis are risk factors for OF in cholangitis with bacteriobilia. The OF scoring system may aid clinicians to identify a poor prognosis group.

关键词： Acute cholangitis Bacteriobilia Bile culture Organ failure

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Stress Oriented Hydrogen Induced Cracking of Linepipe Steel

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Journal of Iron and Steel Research International 2011年第S1期18卷 121-128页

作者： Wan Keun Kim Gyu tae park Kyoo Young Kim Pohang University of Science and Technology Graduate Institute of Ferrous Technology San 31Hyoja-DongPohang 790-784Korea

The stress oriented hydrogen induced cracking (SOHIC) is a typical hydrogen embrittlement phenomenon occurring in the linepipe steels exposed to sour environment containing H 2 S ***,even recently,the cracking mechanism of SOHIC has not been clarified because of lacking in the empirical data on the actual failure mode of SOHIC *** factors affecting SOHIC are discussed in terms of metallurgy of high strength linepipe steel and hydrogen *** cracking mechanisms of SOHIC are examined by comparing them with the empirical failure mode of SOHIC which is developed by observation of the actual fracture sites of the hydrogen induced blister cracking (HIBC) and secondary ***,the correlation between SOHIC and HIC is discussed.

关键词： linepipe steel stress oriented hydrogen induced cracking hydrogen induced cracking metallurgical factor diffusible hydrogen

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Optical Gain Analysis of Graded InGaN/GaN Quantum-Well Lasers

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Chinese Physics Letters 2011年第7期28卷 319-322页

作者： Seoung-Hwan park Yong-tae Moon Jeong Sik Lee Ho Ki Kwon Joong Seo park Doyeol Ahn Department of Electronics Engineering Catholic University of DaeguHayangKyeongsanKyeongbuk 712-702Republic of Korea SLED R&D Center LG Innotek16 Woomyeon-dongSeocho-guSeoul 137-140Republic of Korea Department of Electrical and Computer Engineering University of SeoulSeoul 130-743Republic of Korea

Optical properties of graded InGaN/GaN quantum well(QW)lasers are analyzed as improved gain media for laser diodes emitting near 500 *** results are compared with those of conventional InGaN/GaN QW *** heavy-hole effective mass around the topmost valence band is found to nearly not be affected by the inclusion of the graded *** graded InGaN/GaN QW structure shows a much larger matrix element than the conventional InGaN/GaN QW *** radiative current density dependences of the optical gain are similar to each ***,the graded QW structure is expected to have lower threshold current density than the conventional QW structure because the former has a lower threshold carrier density than the latter.

关键词： InGaN/GaN graded Lasers

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Effect of In Composition on Two-Dimensional Electron Gas in Wurtzite AlGaN/InGaN Heterostructures

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Chinese Physics Letters 2010年第11期27卷 188-190页

作者： KIM Bong-Hwan park Seoung-Hwan LEE Jung-Hee MOON Yong-tae Department of Electronics Engineering Catholic University of Daegu Hayang Kyeongsan Kyeongbuk 712-702 R. Korea School of Electrical Engineering and Computer Science Kyungpook National University Daegu 702-701 R. Korea LG Corporate Institute of Technology 16 Woomyeon-dong Seocho-gu Seoul 137-14-0 R. Korea

The effect of In composition on two-dimensional electron gas in wurtzite AlGaN/InGaN heterostructures is theoretically investigated. The sheet carrier density is shown to increase nearly linearly with In mole fraction x, due to the increase in the polarization charge at the AlGaN/InGaN interface. The electron sheet density is enhanced with the doping in the AlGaN layer. The sheet carrier density is as high as 3.7×1013 cm^-2 at the donor density of 10×1018 cm^-3 for the HEMT structure with x=0.3. The contribution of additional donor density on the electron sheet density is nearly independent of the In mole fraction.

关键词： Condensed matter: electrical magnetic and optical Electronics and devices Semiconductors Surfaces interfaces and thin films Condensed matter: structural mechanical & thermal Nanoscale science and low-D systems

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Microstructure and Tensile Behavior of a Nano-Structured Al-Fe Based Alloy

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Journal of Rare Earths 2004年第Z2期22卷 65-68页

作者： Won-Yong Kim Jae-Sung park Mok-Soon Kim tae-Yeub Ra Advanced Materials R&D Center Korea Institute of Industrial Technology # 472Kajwa-dongSuh-guIncheon 404-254Korea School of Materials Science and EngineeringInha University # 253Yonghyun-dongNam-guIncheon 402-751Korea School of Materials Science and EngineeringInha University # 253Yonghyun-dongNam-guIncheon 402-751Korea Advanced Materials R&D CenterKorea Institute of Industrial Technology # 472Kajwa-dongSuh-guIncheon 404-254Korea

Room temperature deformation behavior of A1-8Fe-2Mo-2V-1Zr alloy produced by spray forming and subsequent warm-extrusion at 693 K and/or rolling at 423 K was investigated in terms of tensile test and microstructural *** the specimen processed by spray forming and warm extrusion, the microstructure consisting of equiaxed grains with the average grain size of 500 nm in the matrix phase and uniformly dispersed fine intermetallic A13(Fe, Mo, V, Zr) and A16(Fe, Mo, V, Zr) phases less than 100 nm was characterized. It was revealed that subsequent warm rolling after warm extrusion promotes precipitation of a fine dispersoid from the supersaturated matrix phase. Warm rolling was found to be effective to increase the yield and tensile strength in the high strain rate regime. Elongation of the warm rolled specimen showed highe r value than extruded specimen over the whole strain rate region studied.

关键词： microstructure tensile deformation A1-Fe based alloy spray forming extrusion warm rolling precipitation strain rate sensitivity

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Implementation of a Subjective Visual Vertical and Horizontal Testing System Using Virtual Reality

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Computers, Materials & Continua 2021年第6期67卷 3669-3679页

作者： Sungjin Lee Min Hong Hongly Va ji-Yun park Department of Software Convergence Soonchunhyang UniversityAsan31538Korea Department of Computer Software Engineering Soonchunhyang UniversityAsan31538Korea Department of Neurology University of Ulsan college of MedicineUlsan University HospitalUlsan44033Korea

Subjective visual vertical(SVV)and subjective visual horizontal(SVH)tests can be used to evaluate the perception of verticality and horizontality,respectively,and can aid the diagnosis of otolith dysfunction in clinical *** this study,SVV and SVH screen version tests are implemented using virtual reality(VR)equipment;the proposed test method promotes a more immersive feeling for the subject while using a simple equipment configuration and possessing excellent *** verify the performance of the proposed VR-based SVV and SVH tests,a reliable comparison was made between the traditional screen-based SVV and SVH tests and the proposed method,based on 30 healthy *** average results of our experimental tests on the VR-based binocular SVV and SVH equipment were−0.15◦±1.74 and 0.60◦±1.18,*** proposed VR-based method satisfies the normal tolerance for horizontal or vertical lines,i.e.,a±3◦error,as defined in previous studies,and it can be used to replace existing test methods.

关键词： Subjective visual vertical subjective visual horizontal virtual reality unity3D FOVE HMD vestibular function tests diagnostic equipment

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gscaLCA in R: Fitting Fuzzy Clustering Analysis Incorporated with Generalized Structured Component Analysis

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Computer Modeling in Engineering & Sciences 2022年第9期132卷 801-822页

作者： ji Hoon Ryoo Seohee park Seongeun Kim Heungsun Hwang Department of Education College of Educational SciencesYonsei UniversitySeoul03722South Korea Psychometrics Department American Board of Internal MedicinePhiladelphia19016USA Department of Educational Research Methodology School of EducationUniversity of North Carolina at GreensboroGreensboro27412USA Department of Psychology McGill UniversityMontrealH3A 0G4Canada

Clustering analysis identifying unknown heterogenous subgroups of a population(or a sample)has become increasingly popular along with the popularity of machine learning *** there are many software packages running clustering analysis,there is a lack of packages conducting clustering analysis within a structural equation modeling *** package,gscaLCA which is implemented in the R statistical computing environment,was developed for conducting clustering analysis and has been extended to a latent variable *** specifically,by applying both fuzzy clustering(FC)algorithm and generalized structured component analysis(GSCA),the package gscaLCA computes membership prevalence and item response probabilities as posterior probabilities,which is applicable in mixture modeling such as latent class analysis in *** a hybrid model between data clustering in classifications and model-based mixture modeling approach,fuzzy clusterwise GSCA,denoted as gscaLCA,encompasses many advantages from both methods:(1)soft partitioning from FC and(2)efficiency in estimating model parameters with bootstrap method via resolution of global optimization problem from *** main function,gscaLCA,works for both binary and ordered categorical *** addition,gscaLCA can be used for latent class regression as *** of profiles of latent classes based on the posterior probabilities is also available in the package *** paper contributes to providing a methodological tool,gscaLCA that applied researchers such as social scientists and medical researchers can apply clustering analysis in their research.

关键词： Fuzzy clustering generalized structured component analysis gscaLCA latent class analysis

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