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Prognostics and health management of alkaline water electrolyzer: Techno-economic analysis considering replacement moment

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Energy and AI 2023年第3期13卷 160-168页

作者： hyunjun Lee Jiwon Gu Boreum Lee hyun-seok cho Hankwon Lim School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology50 UNIST-gilEonyang-eupUlju-gunUlsan 44919Republic of Korea Hydrogen Research Department Future Energy Research DivisionKorea Institute of Energy Research152 Gajeong-roYuseongDaejeonRepublic of Korea Graduate School of Carbon Neutrality Ulsan National Institute of Science and Technology50 UNIST-gilEonyang-eupUlju-gunUlsan 44919Republic of Korea Carbon Neutrality Demonstration and Research Center Ulsan National Institute of Science and Technology50 UNIST-gilEonyang-eupUlju-gunUlsan 44919Republic of Korea

Recently,considerable attention has been paid to the installation of renewable energy capacity to mitigate global CO_(2) emissions.H_(2) produced using water electrolysis and renewable energy is regarded as a clean energy carrier,generating electricity without CO_(2) emissions,called‘Green H 2’.In this paper,a prognostics and health man-agement model for an alkaline water electrolyzer was proposed to predict the load voltage on the electrolyzer to obtain the state of health *** prognostics and health management model was developed by training historical operating data via machine learning models,support vector machine and gaussian process regression,showing the root mean square error of 1.28×10^(−3) and 8.03×10^(−6).In addition,a techno-economic analysis was performed for a green H_(2) production system,composed of 1 MW of photovoltaic plant and 1 MW of alkaline water electrolyzer,to provide economic insights and feasibility of the system.A levelized cost of H_(2) of$6.89 kgH_(2)−1 was calculated and the potential to reach the levelized cost of H_(2) from steam methane reforming with carbon capture and storage was shown by considering the learning rate of the photovoltaic module and ***,the replacement of the alkaline water electrolyzer at around 10 years was preferred to increase the net present value from the green H_(2) production system when capital expenditure and replacement cost are low enough.

关键词： Green H_(2) Alkaline water electrolysis Prognostics and health management Voltage degradation Techno-economic analysis Replacement

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Electrochemical partial reduction of Ni(OH)_(2) to Ni(OH)_(2)/Ni via coupled oxidation of an interfacing NiAl intermetallic compound for robust hydrogen evolution

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Journal of Energy Chemistry 2023年第7期82卷 560-571,I0012页

作者： Young Hwa Yun Kwangsoo Kim Changsoo Lee Byeong-Seon An Ji Hee Kwon Sechan Lee MinJoong Kim Jongsu Seo Jong Hyeok Park Byung-hyun Kim hyun-seok cho Hydrogen Research Department Korea Institute of Energy Research152 Gajeong-roYuseong-guDaejeon 34129Republic of Korea Computational Science&Engineering Laboratory Korea Institute of Energy Research152 Gajeong-roYuseong-guDaejeon 34129Republic of Korea Analysis Center for Energy Research Korea Institute of Energy Research152 Gajeong-roYuseong-guDaejeon 34129Republic of Korea Department of Chemical and Biomolecular Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul 03722Republic of Korea

Ni-based porous electrocatalysts have been widely used in the hydrogen evolution reaction(HER)in alkaline water electrolysis,and the catalysts are produced by selective leaching of Al from Ni-Al *** is well known that chemical leaching of Ni-Al intermetallic compound(IMC)generates a high surface area in Ni(OH)_(2).However,the Ni(OH)_(2) produced by leaching the Ni-Al intermetallic compound retards the hydrogen evolution reaction,which is attributed to its weak hydrogen adsorption *** this study,we controlled the chemical state of Ni using plasma vapor deposition(PVD)followed by heat treatment,selective Al leaching,and electrochemical reduction.X-ray diffraction(XRD),scanning microscopy(SEM),transmission electron microscopy(TEM),and energy-dispersive X-ray spectroscopy(EDS)were used to confirm the phase evolution of the electrocatalysts during *** reveal that the heat-treated Ni-Al alloy with a thick Ni2Al3surface layer underwent selective Al leaching and produced biphasic interfaces comprising Ni(OH)_(2) and NiAl IMCs at the edges of the grains in the outermost surface *** oxidation of the interfacing NiAl IMCs facilitated the partial reduction of Ni(OH)_(2) to Ni(OH)_(2)/Ni in the grains during electrochemical reduction,as confirmed by X-ray photoelectron spectroscopy(XPS).An electrocatalyst containing partially reduced Ni(OH)_(2)/Ni exhibited an overpotential of 54 mV at 10 mA/cm^(2) in a half-cell measurement,and a cell voltage of 1.675 V at 0.4 A/cm2for single-cell operation.A combined experimental and theoretical study(density functional theory calculations)revealed that the superior HER activity was attributed to the presence of partially reduced metallic Ni with various defects and residual Al,which facilitated water adsorption,dissociation,and finally hydrogen evolution.

关键词： Raney nickel HERChemical leaching Intrinsic activity Partial reduction

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Small bowel ulcer bleeding due to suspected clopidogrel use in a patient with clopidogrel resistance:A case report

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World Journal of Clinical Cases 2021年第15期9卷 3689-3695页

作者： Sang Hoon Lee Dong Ryeol Ryu Sung Joon Lee Sung Chul Park Byung Ryul cho Seung Koo Lee Sang Ji choi hyun seok cho Division of Gastroenterology Department of Internal MedicineKangwon National University HospitalKangwon National University School of MedicineChuncheon-si 24289South Korea Division of Cardiology Department of Internal MedicineKangwon National University HospitalKangwon National University School of MedicineChuncheon-si 24289South Korea Department of Anatomic Pathology Kangwon National University HospitalKangwon National University School of MedicineChuncheon-si 24289South Korea Department of Surgery Kangwon National University HospitalKangwon National University School of MedicineChuncheon-si 24289South Korea Department of Hospital Medicine Kangwon National University HospitalChuncheon-si 24289South Korea

BACKGROUND Clopidogrel is a platelet aggregation inhibitor used for the management of cardiovascular *** antiplatelet therapy decreases cardiovascular events after successful coronary drug-eluting stenting,it increases the risk of gastrointestinal(GI)*** 20%of the patients who take clopidogrel exhibit resistance to the *** SUMMARY We report the first case of a small bowel bleeding ulcer in an 86-year-old man with clopidogrel *** had a history of taking clopidogrel due to unstable *** was no evidence of bleeding in the stomach,duodenum,or colon through upper and lower GI *** abdominal computed tomography showed the extravasation of radiocontrast media at the *** of unstable vital signs,emergency surgery was *** ulcers with inflammation were found in the *** pathologic findings revealed simple *** VerifyNow P2Y12 test showed clopidogrel *** year after changing to aspirin,capsule endoscopy was performed and the small bowel ulcers were *** Small bowel ulcers and bleeding due to clopidogrel are not very common,but the prevalence is expected to increase in older age patients with risk factors despite clopidogrel resistance.

关键词： Clopidogrel Resistance Small bowel Multiple ulcers Hematochezia Surgery Case report

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Ungraded Matrix Factorizations as Mirrors of Non-orientable Lagrangians

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Acta Mathematica Sinica,English Series 2024年第1期40卷 26-42页

作者： Lino AMORIM Cheol-hyun cho Department of Mathematics Kansas State University138 Cardwell Hall1228 N.17th StreetManhattanKS 66506USA Department of Mathematical Sciences Research Institute of MathematicsSeoul National UniversitySan 56-1ShinrimdongGwanakguSeoul 47907South Korea

We introduce the notion of ungraded matrix factorization as a mirror of non-orientable Lagrangian *** ungraded matrix factorization of a polynomial W,with coefficients in a field of characteristic 2,is a square matrix Q of polynomial entries satisfying Q^(2)=W·*** then show that non-orientable Lagrangians correspond to ungraded matrix factorizations under the localized mirror functor and illustrate this construction in a few *** main example is the Lagrangian submanifold RP^(2)⊂CP^(2)and its mirror ungraded matrix factorization,which we construct and *** particular,we prove a version of Homological Mirror Symmetry in this setting.

关键词： Mirror symmetry non-orientable Lagrangian submanifold matrix factorization

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Crystal reconstruction of V2O3/carbon heterointerfaces via anodic hydration for ultrafast and reversible Mg-ion battery cathodes

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InfoMat 2024年第3期6卷 95-107页

作者： Gun Jang Yun Sang Joe Sang Joon Lee hyun Gyu cho Sang Ha Baek Peixun Xiong Kang Ho Shin Jeong seok Yeon Min Su Kang Si Hyoung Oh Ho seok Park School of Chemical Engineering Sungkyunkwan University(SKKU)SuwonRepublic of Korea Advanced Batteries Research Center Korea Electronics Technology InstituteSeongnamRepublic of Korea Korea Institute of Science and Technology SeoulRepublic of Korea SKKU Advanced Institute of Nano Technology(SAINT) Sungkyunkwan UniversitySuwonRepublic of Korea Department of Health Sciences and Technology Samsung Advanced Institute for Health Sciences and Technology(SAIHST)Sungkyunkwan UniversitySuwonRepublic of Korea SKKU Institute of Energy Science and Technology(SIEST) Sungkyunkwan UniversitySuwonRepublic of Korea

Magnesium-ion batteries(MIBs)have promising applications because of their high theoretical capacity and the natural abundance of magnesium ***,the kinetic performance and cyclic stability of cathode materials are limited by the strong interactions between Mg ions and the crystal ***,we demonstrate the unique Mg^(2+)-ion storage mechanism of a hierarchical accordion-like vanadium oxide/carbon heterointerface(V2O3@C),where the V2O3 crystalline structure is reconstructed into a MgV_(3)O_(7)·H_(2)O phase through an anodic hydration reaction upon first cycle,for the improved kinetic and cyclic *** verified by in situ/ex situ spectroscopic and electrochemical analyses,the fast charge transfer kinetics of the V2O3@C cathode were due to the crystal-reconstruction and chemically coupled *** V2O3@C demonstrated an ultrahigh rate capacity of 130.4 mAh g^(-1)at 50000 mA g^(-1)and 1000 cycles,achieving a Coulombic efficiency of 99.6%.The high capacity of 381.0 mA h g^(-1)can be attributed to the reversible Mg^(2+)-ion intercalation mechanism observed in the MgV_(3)O_(7)·H_(2)O phase using a 0.3 M Mg(TFSI)2/ACN(H_(2)O)***,within the voltage range of 2.25 V versus Mg/Mg^(2+),the V2O3@C exhibited a capacity of 245.1 mAh g^(-1)when evaluated with magnesium metal in a 0.3 M Mg(TFSI)^(2+)0.25 M MgCl_(2)/DME *** research findings have important implications for understanding the relationship between the Mg-ion storage mechanism and reconstructed crystal phase of vanadium oxides as well as the heterointerface reconstruction for the rational design of MIB cathode materials.

关键词： anodic hydration reaction magnesium ion battery nano crystal vanadium oxide

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Defect Detection Model Using Time Series Data Augmentation and Transformation

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Computers, Materials & Continua 2024年第2期78卷 1713-1730页

作者： Gyu-Il Kim hyun Yoo Han-Jin cho Kyungyong Chung Department of Computer Science Kyonggi UniversitySuwon-si16227Korea Contents Convergence Software Research Institue Kyonggi UniversitySuwon-si16227Korea Department of Energy IT Engineering Far East UniversityEumsung-gun27601Korea Division of AI Computer Science and Engineering Kyonggi UniversitySuwon-si16227Korea

Time-series data provide important information in many fields,and their processing and analysis have been the focus of much ***,detecting anomalies is very difficult due to data imbalance,temporal dependence,and ***,methodologies for data augmentation and conversion of time series data into images for analysis have been *** paper proposes a fault detection model that uses time series data augmentation and transformation to address the problems of data imbalance,temporal dependence,and robustness to *** method of data augmentation is set as the addition of *** involves adding Gaussian noise,with the noise level set to 0.002,to maximize the generalization performance of the *** addition,we use the Markov Transition Field(MTF)method to effectively visualize the dynamic transitions of the data while converting the time series data into *** enables the identification of patterns in time series data and assists in capturing the sequential dependencies of the *** anomaly detection,the PatchCore model is applied to show excellent performance,and the detected anomaly areas are represented as heat *** allows for the detection of anomalies,and by applying an anomaly map to the original image,it is possible to capture the areas where anomalies *** performance evaluation shows that both F1-score and Accuracy are high when time series data is converted to ***,when processed as images rather than as time series data,there was a significant reduction in both the size of the data and the training *** proposed method can provide an important springboard for research in the field of anomaly detection using time series ***,it helps solve problems such as analyzing complex patterns in data lightweight.

关键词： Defect detection time series deep learning data augmentation data transformation

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Depolarization mitigated in ferroelectric Hf_(0.5)Zr_(0.5)O_(2)ultrathin films(<5 nm)on Si substrate by interface engineering

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Journal of Advanced Ceramics 2024年第3期13卷 282-292页

作者： Se hyun Kim Younghwan Lee Dong hyun Lee Geun Hyeong Park hyun Woo Jeong Kun Yang Yong Hyeon cho Young Yong Kim Min Hyuk Park Department of Materials Science and Engineering College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Research Institute of Advanced Materials College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Inter-university Semiconductor Research Center College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Pohang Accelerator Laboratory Pohang University of Science&TechnologyPohang 790784Republic of Korea

(Hf,Zr)O_(2)offers considerable potential for next-generation semiconductor devices owing to its nonvolatile spontaneous polarization at the ***,scaling this material to sub-5 nm thickness poses several challenges,including the formation of an interfacial layer and high trap *** particular,a low-k SiO_(2)interfacial layer is naturally formed when(Hf,Zr)O_(2)films are directly grown on a Si substrate,leading to high depolarization fields and rapid reduction of the remanent *** address these issues,we conducted a study to significantly improve ferroelectricity and switching endurance of(Hf,Zr)O_(2)films with sub-5 nm thicknesses by inserting a TiO_(2)interfacial *** deposition of a Ti film prior to Hf_(0.5)Zr_(0.5)O_(2)film deposition resulted in a high-k TiO_(2)interfacial layer and prevented the direct contact of Hf_(0.5)Zr_(0.5)O_(2)with *** findings show that the high-k TiO_(2)interfacial layer can reduce the SiO_(2)/Si interface trap density and the depolarization field,resulting in a switchable polarization of 60.2μC/cm^(2)for a 5 nm thick Hf_(0.5)Zr_(0.5)O_(2)***,we propose that inserting a high-k TiO_(2)interfacial layer between the Hf_(0.5)Zr_(0.5)O_(2)film and the Si substrate may offer a promising solution to enhancing the ferroelectricity and reliability of(Hf,Zr)O_(2)grown on the Si substrate and can pave the way for next-generation semiconductor devices with improved performance.

关键词： ferroelectric charge trapping hafnia depolarization

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Bone-targeted lipoplex-loaded three-dimensional bioprinting bilayer scaffold enhanced bone regeneration

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Regenerative Biomaterials 2024年第4期3卷 138-148页

作者： Woo-Jin Kim Jeong-hyun Ryu Ji Won Kim Ki-Tae Kim Hye-Rim Shin Heein Yoon hyun-Mo Ryoo Young-Dan cho Department of Molecular Genetics School of Dentistry and Dental Research InstituteSeoul National UniversitySeoul03080Republic of Korea Department of Periodontology School of Dentistry and Dental Research InstituteSeoul National University and Seoul National University Dental HospitalSeoul03080Republic of Korea

Clinical bone-morphogenetic protein 2(BMP2)treatment for bone regeneration,often resulting in complications like soft tissue inflammation and ectopic ossification due to high dosages and non-specific delivery systems,necessitates research into improved biomaterials for better BMP2 stability and *** tackle this challenge,we introduced a groundbreaking bone-targeted,lipoplex-loaded,three-dimensional bioprinted bilayer scaffold,termed the polycaprolactone-bioink-nanoparticle(PBN)scaffold,aimed at boosting bone *** encapsulated BMP2 within the fibroin nanoparticle based lipoplex(Fibroplex)and functionalized it with DSS6 for bone tissue-specific targeting.3D printing technology enables customized,porous PCL scaffolds for bone healing and soft tissue growth,with a two-step bioprinting process creating a cellular lattice structure and a bioink grid using gelatin-alginate hydrogel and DSS6-Fibroplex,shown to support effective nutrient exchange and cell growth at specific pore *** PBN scaffold is predicted through in silico analysis to exhibit biased BMP2 release between bone and soft tissue,a finding validated by in vitro osteogenic differentiation *** PBN scaffold was evaluated for critical calvarial defects,focusing on sustained BMP2 delivery,prevention of soft tissue cell infiltration and controlled fiber membrane pore size in *** PBN scaffold demonstrated a more than eight times longer BMP2 release time than that of the collagen sponge,promoting osteogenic differentiation and bone regeneration in a calvarial defect *** findings suggest that the PBN scaffold enhanced the local concentration of BMP2 in bone defects through sustained release and improved the spatial arrangement of bone formation,thereby reducing the risk of heterotopic ossification.

关键词： 3D bioprinting bone-targeting lipoplex BMP2 bone regeneration

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Effect of Meteorological Data Assimilation on Regional Air Quality Forecasts over the Korean Peninsula

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Journal of Meteorological Research 2024年第2期38卷 262-284页

作者： Yunjae cho hyun Mee KIM Eun-Gyeong YANG Yonghee LEE Jae-Bum LEE Soyoung HA Department of Atmospheric Sciences Yonsei UniversitySeoul 03722Republic of Korea Air Quality Forecasting Center National Institute of Environmental ResearchIncheon 22689Republic of Korea National Center for Atmospheric Research BoulderCO 80305USA University of Maryland Baltimore County BaltimoreMD 21250USA Global Modeling and Assimilation Office NASA Goddard Space Flight CenterGreenbeltMD 20771USA

The Weather Research and Forecasting model coupled with Chemistry(WRF-Chem),a type of online coupled chemistry-meteorology model(CCMM),considers the interaction between air quality and meteorology to improve air quality *** data assimilation(DA)can be used to reduce uncertainty in meteorological field,which is one factor causing prediction uncertainty in the *** this study,WRF-Chem and three-dimensional variational DA were used to examine the impact of meteorological DA on air quality and meteorological forecasts over the Korean *** nesting model domains were configured over East Asia(outer domain)and the Korean Peninsula(inner domain).Three experiments were conducted by using different DA domains to determine the optimal model domain for the meteorological *** the meteorological DA was performed in the outer domain or both the outer and inner domains,the root-mean-square error(RMSE),bias of the predicted particulate matter(PM)concentrations,and the RMSE of predicted meteorological variables against the observations were smaller than those in the experiment where the meteorological DA was performed only in the inner *** indicates that the improvement of the synoptic meteorological fields by DA in the outer domain enhanced the meteorological initial and boundary conditions for the inner domain,subsequently improving air quality and meteorological *** to the experiment without meteorological DA,the RMSE and bias of the meteorological and PM variables were smaller in the experiments with *** effect of meteorological DA on the improvement of PM predictions lasted for approximately 58-66 h,depending on the ***,the uncertainty reduction in the meteorological initial condition by the meteorological DA contributed to a reduction of the forecast errors of both meteorology and air quality.

关键词： meteorological data assimilation regional air quality forecast particulate matter concentration optimal model domain forecast error WRF-Chem

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Endoscopic ultrasound-guided tissue sampling induced pancreatic duct leak resolved by the placement of a pancreatic stent:A case report

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World Journal of Clinical Cases 2024年第9期12卷 1677-1684页

作者： Ki-hyun Kim Chang Hwan Park Eunae cho Yohan Lee Department of Internal Medicine Chonnam National University HospitalGwangju 61469South Korea Department of Gastroenterology Chonnam National University HospitalGwangju 61469South Korea

BACKGROUND Pancreatic ductal leaks complicated by endoscopic ultrasonography-guided tissue sampling(EUS-TS)can manifest as acute *** SUMMARY A 63-year-old man presented with persistent abdominal pain and weight ***:Laboratory findings revealed elevated carbohydrate antigen 19-9(5920 U/mL)and carcinoembryonic antigen(23.7 ng/mL)*** resonance imaging of the pancreas revealed an approximately 3 cm ill-defined space-occupying lesion in the inferior aspect of the head,with severe encasement of the superior mesenteric *** ductal adenocarcinoma was confirmed after pathological examination of specimens obtained by EUS-TS using the fanning *** and outcomes:The following day,the patient experienced severe abdominal pain with high amylase(265 U/L)and lipase(1173 U/L)*** tomography of the abdomen revealed edematous wall thickening of the second portion of the duodenum with adjacent fluid collections and a suspicious leak from either the distal common bile duct or the main pancreatic duct in the *** retrograde cholangiopancreatography revealed dye leakage in the head of the main pancreatic ***,a 5F 7 cm linear plastic stent was deployed into the pancreatic duct to divert the pancreatic *** patient’s abdominal pain improved immediately after pancreatic stent insertion,and amylase and lipase levels normalized within a *** chemotherapy was then *** Using the fanning method in EUS-TS can inadvertently cause damage to the pancreatic duct and may lead to clinically significant *** a pancreatic stent may immediately resolve acute pancreatitis and shorten the waiting time for curative *** using the fanning method during EUSTS,ductal structures should be excluded to prevent pancreatic ductal leakage.

关键词： Endoscopic ultrasound-guided tissue sampling Pancreatitis Pancreatic duct leak Pancreatic stent Case report

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