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System reliability analysis of downstream spillways based on collapse of upstream spillways

International Journal of Agricultural and Biological Engineering 2015年第4期8卷 140-150,I0003页

作者： won choi Jeongbae Jeon Jinseon Park JeongJae Lee Seongsoo Yoon Department of Rural Systems Engineering College of Agriculture and Life SciencesSeoul National UniversitySeoul 151-921South Korea Department of Agricultural and Rural Engineering College of AgricultureLife and Environments SciencesChungbuk National UniversityChungbuk 362-763South Korea Department of Rural Systems Engineering Research Institute of Agriculture and Life SciencesCollege of Agriculture and Life SciencesSeoul National UniversitySeoul 151-921South Korea

Some agricultural reservoirs in South Korea are vulnerable to situations in which they are unable to function as reservoirs because of essential safety *** is because 70%of existing agricultural reservoirs were originally constructed more than 50 years ago;most of these reservoirs have not been maintained or managed since their initial *** the worst cases,reservoirs are connected to one another by short distances and/or the sizes of upstream reservoirs are larger than the sizes of downstream *** components of the reservoirs,such as their embankments,spillways,and water intake facilities,have been considered in order to understand the main factors associated with potential reservoir ***,this study aims to estimate the probability of failure in downstream spillways upon the collapse of upstream spillways(for reservoirs connected in series).A simple equation to calculate the rise in the water level in downstream spillways,which is caused by the collapse of upstream spillways,was *** equation was based on the discharge equation of an overflowing rectangular weir and the scaling law for continuous *** verify the proposed simple equation,the water level increments were compared with the simulated results of the commercial software FLOW-3D,which is an accurate computational fluid dynamics(CFD)program that is used for tracking free-surface *** values predicted through the simple formula were close to the simulated data(within a maximum prediction error of 5%).The values were updated to reflect the effects of hydraulic pressures on the walls of downstream spillways,thereby allowing the failure probabilities(due to overturning,sliding,and settlement)of the downstream spillways to be *** study found that the failure probabilities of independent components in reservoirs are significantly different from the systematic failure values observed in sequential modes.

关键词： failure probability collapse spillway discharge scaling law FLOW-3D

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Enhancing BiVO_(4)photoanode performance by insertion of an epitaxial BiFeO_(3)ferroelectric layer

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Journal of Energy Chemistry 2024年第2期89卷 71-78,I0003页

作者： Haejin Jang Yejoon Kim Hojoong choi Jiwoong Yang Yoonsung Jung Sungkyun choi Donghyeon Lee Ho won Jang Sanghan Lee School of Materials Science and Engineering Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea Department of Materials Science and Engineering Seoul National UniversitySeoul 08826Republic of Korea

BiVO_(4)(BVO)is a promising material as the photoanode for use in photoelectrochemical ***,the high charge recombination and slow charge transfer of the BVO have been obstacles to achieving satisfactory photoelectrochemical *** address this,various modifications have been attempted,including the use of ferroelectric *** materials can form a permanent polarization within the layer,enhancing the separation and transport of photo-excited electron-hole *** this study,we propose a novel approach by depositing an epitaxial BiFeO_(3)(BFO)thin film underneath the BVO thin film(BVO/BFO)to harness the ferroelectric property of *** self-polarization of the inserted BFO thin film simultaneously functions as a buffer layer to enhance charge transport and a hole-blocking layer to reduce charge *** a result,the BVO/BFO photoanodes showed more than 3.5 times higher photocurrent density(0.65 mA cm^(-2))at 1.23 V_(RHE)under the illumination compared to the bare BVO photoanodes(0.18 m A cm^(-2)),which is consistent with the increase of the applied bias photon-to-current conversion efficiencies(ABPE)and the result of electrochemical impedance spectroscopy(EIS)*** results can be attributed to the self-polarization exhibited by the inserted BFO thin film,which promoted the charge separation and transfer efficiency of the BVO photoanodes.

关键词： Photoelectrochemical Photoanode BiVO_(4) Ferroelectric materials BiFeO_(3)

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Zircon U-Pb ages and O-Hf isotopes of Quaternary trachytes from the East Sea:Implications for the genesis of low-δ^(18)O magmas

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Geoscience Frontiers 2024年第2期15卷 41-54页

作者： Hyun-Ok choi Jihye Oh Chang Hwan Kim Soon Young choi won Hyuck Kim Chan Hong Park Dokdo Research Center East Sea Research InstituteKorea Institute of Ocean Science and TechnologyUljin 36315Republic of Korea Deep-Sea and Seabed Mineral Resources Research Center Korea Institute of Ocean Science and TechnologyBusan 49111Republic of Korea Division of Science Education Kangwon National University1 Gangwondaehak-gilChuncheon-siGangwon-do 24341Republic of Korea

Quaternary intraplate magmatism formed several volcanic islands and seamounts,including Dokdo(DD),Ulleungdo(UD),Simheungtack(ST),Anyongbok,and Isabu in the southwest of the East Sea back-arc *** this study,we present whole-rock geochemical,zircon U–Pb age,and in situ O–Hf isotope data for the submerged volcanic rocks from DD,UD,and ST to provide new insights into the eruption timing of these volcanoes and constrain the magma evolution *** samples used in this study were trachytes and exhibited ferroan,alkalic,and metaluminous to weakly peraluminous *** showed light rare earth element(REE)-enriched patterns with(La/Yb)N ratios of 25.3–31.7 and mostly negative Eu anomalies in a chondrite-normalized REE *** addition,they were enriched in large-ion lithophile elements and high field strength elements;they exhibited positive Pb anomalies and strongly negative Ba,Sr,P,and Ti *** zircons yielded a weighted-mean 206Pb/238U age of 2.61,0.348–0.704,and 2.76–2.94 Ma for the DD,UD,and ST trachytes,*** zircons exhibited lowerδ^(18)O values than normal depleted mantle values,regardless of the crystallization age and spatial distribution of ***δ^(18)O values showed no correlation with U contents or Th/U ratios,indicating that the lowδ^(18)O signatures were of primary magmatic *** Hf isotopic compositions of the zircons were relatively heterogeneous but predominately characterized by positive eHf *** O–Hf mixing modeling revealed that low-δ^(18)O rocks with positive eHf values from the UD and ST volcanoes were derived from a hybrid source of recycled juvenile crustal materials with low-δ^(18)O and positive eHf signatures and an enriched mantle source with normalδ^(18)O and negative eHf *** juvenile oceanic crust in the source was likely metasomatized by seawater at high temperatures prior to *** contrast,the felsic magma that formed the DD volcanoes may have assimilated with regional

关键词： Quaternary intraplate volcanism East Sea Zircon O-Hf isotopes Low-δ^(18)O magma Recycled juvenile oceanic crust

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Influence of the h TERT rs2736100 polymorphism on telomere length in gastric cancer

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World Journal of Gastroenterology 2015年第31期21卷 9328-9336页

作者： Byung Joon choi Jung Hwan Yoon Olga Kim won Suk choi Suk Woo Nam Jung Young Lee won Sang Park Department of Pediatrics College of MedicineThe Catholic University of Korea Department of Pathology College of MedicineThe Catholic University of Korea Functional Rnomics Research Center College of MedicineThe Catholic University of Korea

AIM: To investigate the functional consequences of rs2736100 polymorphism in telomere length and examine its link to gastric cancer ***: Telomere length and human telomerase reverse transcriptase(h TERT) m RNA expression were measured in 35 gastric cancer tissues and 5 cell lines and correlated to rs2736100 polymorphism. The relationship between rs2736100 polymorphism and the risk of gastric cancer were examined in 243 gastric cancer patients and 246 healthy ***: The rs2736100 A allele carrier is closely associated with reduced h TERT m RNA expression and shortened telomere length in gastric cancer tissue and cell lines. When gastric cancers were stratified by histological subtype,telomere length and h TERT m RNA levels were significantly increased in those with the C/C genotype in intestinal-type gastric cancer,but not in diffuse-type gastric cancer. Interestingly,there was no significant difference in the genotype and allele frequencies of the rs2736100 polymorphism between the patients with gastric cancer and healthy ***: The rs2736100 polymorphism of the h TERT gene is involved in the regulation of h TERT expression and telomere length,but not in the risk of gastric cancer.

关键词： Human telomerase reverse transcriptase Telomere Ga

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Functions of hepatic non-parenchymal cells in alcoholic liver disease

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Liver Research 2019年第2期3卷 80-87页

作者： won-Mook choi Myung-Ho Kim won-Il Jeong Laboratory of Liver Research Graduate School of Medical Science and EngineeringKorea Advanced Institute of Science and Technology(KAIST)DaejeonRepublic of Korea Department of Gastroenterology Liver CenterAsan Medical CenterUniversity of Ulsan College of MedicineSeoulRepublic of Korea

Alcoholic liver disease(ALD)represents a wide spectrum of disease from simple steatosis to *** there have been multiple attempts to treat ALD,its treatment is still based on abstinence from alcohol and using corticosteroids in specified ***,nearly 40%of patients with ALD who are in need of treatment are unresponsive to the current treatments,which implies a new paradigm shift for the treatment of ***,earlier studies have focused on the abnormal metabolism occurring in the hepatocytes as a protagonist in the pathogenesis of ***,increasing evidence suggests that non-parenchymal cells,such as hepatic stellate cells(HSCs),kupffer cells,liver sinusoidal endothelial cells,and immune cells around the hepatocytes have critical roles in multiple stages of ALD either by direct or indirect cell-to-cell *** instance,in the early stage of ALD,kupffer cells and HSCs located closely to hepatocytes contribute to the development of alcoholic steatosis and inflammation through the secretion of various inflammatory cytokines(immunologic pathways)and the activation of the endocannabinoid system(metabolic pathways).While the stage of ALD progresses to alcoholic hepatitis and fibrosis,various cell-to-cell interactions with infiltrating immune cells become highly significant at the multicellular *** review explains the diverse roles of non-parenchymal cells in the progression of ALD,as well as potential therapeutic strategies to treat ALD.

关键词： Alcoholic liver disease(ALD) Hepatic stellate cell(HSC) Immune cell kupffer cell Natural killer(NK)cell Steatosis Steatohepatitis Fibrosis

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Epidural blood patch for spontaneous intracranial hypotension with subdural hematoma: A case report and review of literature

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World Journal of Clinical Cases 2022年第1期10卷 388-396页

作者： Se Hee choi Youn Young Lee won-Joong Kim Anesthesiology and Pain Medicine Ewha Womans University Mokdong HospitalSeoul 07985South Korea Anesthesiology and Pain Medicine School of MedicineEwha Womans UniversitySeoul 07985South Korea

BACKGROUND Cerebrospinal fluid(CSF)leakage at C1/2 in spontaneous intracranial hypotension(SIH)is *** hematoma(SDH),a serious complication of SIH,may lead to neurological *** report presents a case of SDH after spontaneous C1/2 CSF leakage,which was treated with a targeted epidural blood patch(EBP).CASE SUMMARY A 60-year-old man with no history of trauma was admitted to our hospital with orthostatic headache,nausea,and *** computed tomography imaging revealed bilateral,subacute to chronic *** magnetic resonance imaging(MRI)findings were SDH with dural enhancement in the bilateral cerebral convexity and posterior fossa and mild sagging,suggesting *** the patient underwent burr hole trephination,the patient’s orthostatic headache was *** myelography led to a suspicion of CSF leakage at C1/***,we performed a targeted cervical EBP using an epidural catheter under fluoroscopic *** 5 d after EBP,a follow-up MR myelography revealed a decrease in the interval size of the CSF *** his symptoms improved,the patient still complained of headaches;therefore,we repeated the targeted cervical EBP 6 d after the initial ***,his headache had almost disappeared on the 8th day after the repeated *** Targeted EBP is an effective treatment for SDH in patients with SIH due to CSF leakage at C1/2.

关键词： Cerebrospinal fluid Chronic subdural hematoma Epidural blood patch Myelography Spontaneous intracranial hypotension Case report

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Numerical Visualization of Air Intake Induced by Free Surface Vortex

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Journal of Thermal Science 2017年第6期26卷 540-544页

作者： Young Kyu Park Mohan kumar Dey Yoon Hwan choi Yeon won Lee Research Institute of Industrial Science & Technology Pukyong National University Busan Korea Interdisciplinary Program of Biomedical Mechanical and Electrical Engineering Pukyong National University Busan Korea Department of Mechanical Design Engineering Pukyong National University Busan Korea

Free surface vortex control is vital in a pump sump system because the air absorbed by free surface vortex induc- es noise, vibration, and cavitation corrosion on the pumping system. In this study, the change of free surface vor- tex and air absorption in a pump intake has been investigated by the Volume of Fraction （VOF） method with steady multiphase flow model in order to represent the behavior of the free surface vortex exactly. The homoge- neous free surface model is used to apply interactions of air and water. The results show that air intake by the free surface vortex motion can be visualized using the iso-surface of air volume fraction. The vortices make an air column from the free surface to the pump intake. Also, it was found that the flee surface vortex can be controlled by installing curtain walls.

关键词： free surface vortex numerical visualization curtain wall air intake

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Synergistic passivation of MAPbI_(3) perovskite solar cells by compositional engineering using acetamidinium bromide additives

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Journal of Energy Chemistry 2021年第8期30卷 755-762,I0016页

作者： Kyungeun Jung Weon-Sik Chae Jae won choi Ki Chul Kim Man-Jong Lee Department of Chemistry Konkuk University143-701 SeoulSouth Korea Department of Advanced Technology Fusion Konkuk University143-701 SeoulSouth Korea Analysis Research Division Daegu CenterKorea Basic Science Institute702-701 DaeguSouth Korea Division of Chemical Engineering Konkuk University05029 SeoulSouth Korea

For the global commercialization of highly efficient and stable perovskite solar cells(PSCs),it is necessary to effectively suppress the formation of various defects acting as nonradiative recombination sources in perovskite light-harvesting *** defects between the charge-selective layer and the perovskite are easily formed in the solution process used to fabricate perovskite *** addition,owing to the difference in thermal expansion coefficients between the substrate and the perovskite film,internal residual tensile stress inevitably occurs,resulting in increased nonradiative ***,a simple compositional engineering scheme for realizing efficient and stable PSCs,which incorporates acetamidinium bromide(AABr)as an additive into the MAPbI_(3) lattice,is *** an additive,AABr has been found to provide synergistic multiple passivation for both internal and interfacial *** was found to effectively release the tensile strain of the MAPbI_(3) film by forming a structure stabilized by NH-I hydrogen bonds,as evidenced by calculations based on density functional theory(DFT).Furthermore,the incorporated AABr additives created a charge carrier recombination barrier to enhance charge collection capability by reducing interfacial ***,a power conversion efficiency(PCE)of 20.18%was achieved using a planar device employing AABr-incorporated MAPbI_(3).This was substantially higher than the 18.32% PCE of a pristine MAPbI_(3)-based ***,unencapsulated PSCs using AABr-incorporated MAPbI_(3) absorbers exhibited excellent long-term stability,maintaining>95% of initial PCE up to 1200 hours in ambient air.

关键词： Acetamidinium bromide Planar perovskite solar cell Tensile stress Interface passivation Recombination barrier

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Exploratory Data Analysis Applied in Mapping Multi-element Soil Geochemical Anomalies for Drill Target Definition:A Case Study from the Unpha Layered Non-magmatic Hydrothermal Pb-Zn Deposit,DPR Korea

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Acta Geologica Sinica(English Edition) 2021年第4期95卷 1357-1365页

作者： JANG Gwang-Hyok won Hyon-Chol HWANG Bo-Hyon choi Chol-Man Faculty of Geology Kim Il Sung UniversityPyongyangDemocratic People's Republic of Korea

A factor analysis was applied to soil geochemical data to define anomalies related to buried Pb-Zn mineralization.A favorable main factor with a strong association of the elements Zn,Cu and Pb,related to mineralization,was selected for *** median+2 MAD(median absolute deviation)method of exploratory data analysis(EDA)and C-A(concentration-area)fractal modeling were then applied to the Mahalanobis distance,as defined by Zn,Cu and Pb from the factor analysis to set the thresholds for defining multi-element *** a result,the median+2 MAD method more successfully identified the Pb-Zn mineralization than the C-A fractal *** soil anomaly identified by the median+2 MAD method on the Mahalanobis distances defined by three principal elements(Zn,Cu and Pb)rather than thirteen elements(Co,Zn,Cu,V,Mo,Ni,Cr,Mn,Pb,Ba,Sr,Zr and Ti)was the more favorable reflection of the ore *** identified soil geochemical anomalies were compared with the in situ economic Pb-Zn ore bodies for *** results showed that the median+2 MAD approach is capable of mapping both strong and weak geochemical anomalies related to buried Pb-Zn mineralization,which is therefore useful at the reconnaissance drilling stage.

关键词： factor analysis exploratory data analysis Mahalanobis distance multi-element Unpha

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Decellularized sciatic nerve matrix as a biodegradable conduit for peripheral nerve regeneration

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Neural Regeneration Research 2018年第10期13卷 1796-1803页

作者： Jongbae choi Jun Ho Kim Ji Wook Jang Hyun Jung Kim Sung Hoon choi Sung won Kwon R&D Center Genewel Co.Ltd. Department of Surgery CHA Bundang Medical CenterCHA University

The use of autologous nerve grafts remains the gold standard for treating nerve defects, but current nerve repair techniques are limited by donor tissue availability and morbidity associated with tissue loss. Recently, the use of conduits in nerve injury repair, made possible by tissue engineering, has shown therapeutic potential. We manufactured a biodegradable, collagen-based nerve conduit containing decellularized sciatic nerve matrix and compared this with a silicone conduit for peripheral nerve regeneration using a rat model. The collagen-based conduit contains nerve growth factor, brain-derived neurotrophic factor, and laminin, as demonstrated by enzyme-linked immunosorbent assay. Scanning electron microscopy images showed that the collagen-based conduit had an outer wall to prevent scar tissue infiltration and a porous inner structure to allow axonal growth. Rats that were implanted with the collagen-based conduit to bridge a sciatic nerve defect experienced significantly improved motor and sensory nerve functions and greatly enhanced nerve regeneration compared with rats in the sham control group and the silicone conduit group. Our results suggest that the biodegradable collagen-based nerve conduit is more effective for peripheral nerve regeneration than the silicone conduit.

关键词： nerve regeneration biodegradable decellularized collagen nerve conduit growth factor peripheral nerve injury regeneration silicone conduit rat model

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