检索结果-南通市图书馆

Journal of Materials Science & Technology 2022年第10期105卷 45-56页

作者： Keekeun kim Damhyun kim Kibum Park Junghan Yun chang-Sung Seok School of Mechanical Engineering Sungkyunkwan UniversitySuwonGyeonggi 440-746Korea

The lifespan of plasma-sprayed thermal barrier coating(TBC)systems is difficult to predict owing to the variety of microstructures and deterioration *** this study,we developed a novel TBC damage model to reflect deterioration histories;thus,it can be applied to various *** to TBCs is classifed into oxidation and mechanical damage;therefore,a detailed deterioration history can be *** addition,by introducing a virtual S–N diagram,a life prediction model that can be applied to TBCs with various microstructures was *** used the proposed damage and life prediction models in isothermal aging and thermal cycle tests with different aging *** predicted lifespan of TBCs by using the proposed models was within 95%of the results obtained by performing actual tests in the temperature range of 1150–1350℃.

关键词： Thermal barrier coatings Damage model Temperature history Thermal fatigue Life prediction model

Mixing of two different electrolyte solutions in electromagnetic rectangular mixers

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2016年第1期28卷 114-124页

作者： Meimei WEN chang Nyung kim Yue YAN Department of Mechanical Engineering Graduate School Kyung Hee University Department of Mechanical Engineering College of Engineering Kyung Hee University

This study proposes a new electromagnetic rectangular mixer, and numerically examines the mixing characteristics of two different electrolyte solutions in the device under a uniform magnetic field. The mixer consists of a conduit with electrodes equipped on its top and bottom walls. The difference in the electric potentials applied to the sets of electrodes induces the current. The combination of the induced current and magnetic field yields Lorentz force, resulting in the fluid motion for pumping and mixing of the two different fluids. The numerical simulation is carried out with the use of commercial software CFX. The present numerical model is validated by an existing numerical work. The effect of different variables on mixing efficiency is investigated in many different cases with two different heights of the duct and various input voltages of the electrodes. The current simulation results indicate that the mixing performance can be enhanced by using multiple sets of electrodes and applying higher input voltages（absolute values） to the electrodes.

关键词： CFX electrolyte solution Lorentz force mixer mixing efficiency

ψValuation ideals and primary w-ideals

在线全文

学校读者我要写书评

暂无评论

Frontiers of Mathematics in China 2016年第4期11卷 829-844页

作者： Gyu Whan chang Hwaukoo kim Department of Mathematics Education Incheon National University Incheon 406-772 Republic of Korea Department of Information Security Hoseo University Asan 336-795 Republic of Korea

Let D be an integral domain, ψ（D）（resp., t-ψ（D）） be the set of all valuation （resp., t-valuation） ideals of D, and w-P（D） be the set of primary w-ideals of D. Let D[X] be the polynomial ring over 19, c（f） be the ideal of D generated by the coefficients of f ∈ D[X], and Nv = {f∈ D[X] ｜ c（f）v = D}. In this paper, we study integral domains D in which w-P（D） t-ψ（D）, t-ψ（D） w-P（D）, or t-ψ（D） = w-P（D）. We also study the relationship between t-ψ（D） and ψ（D[X]Nv）, and characterize when t-ψ（A ＋ XB[X]） w-P（A ＋ XB[X]） holds for a proper extension A c B of integral domains.

关键词： t-Valuation ideal primary w-ideal PvMD UMT-domain D[X]Nv

Scalable Ir-Doped NiFe₂O₄/TiO₂ Heterojunction Anode for Decentralized Saline Wastewater Treatment and H₂ Production

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

NANO-MICRO LETTERS 2025年第1期17卷 1-18页

作者： Hong, Sukhwa kim, Jiseon Park, Jaebeom Im, Sunmi Hoffmann, Michael R. Cho, Kangwoo Pohang Univ Sci & Technol POSTECH Div Environm Sci & Engn Pohang 790784 South Korea CALTECH Linde Labs Pasadena CA 91125 USA Yonsei Univ Int Campus Inst Convergence Res & Educ Adv Technol I CREATE Incheon 21983 South Korea

Wastewater electrolysis cells (WECs) for decentralized wastewater treatment/reuse coupled with H-2 production can reduce the carbon footprint associated with transportation of water, waste, and energy carrier. This study reports Ir-doped NiFe2O4 (NFI, similar to 5 at% Ir) spinel layer with TiO2 overlayer (NFI/TiO2), as a scalable heterojunction anode for direct electrolysis of wastewater with circumneutral pH in a single-compartment cell. In dilute (0.1 M) NaCl solutions, the NFI/TiO2 marks superior activity and selectivity for chlorine evolution reaction, outperforming the benchmark IrO2. Robust operation in near-neutral pH was confirmed. Electroanalyses including operando X-ray absorption spectroscopy unveiled crucial roles of TiO2 which serves both as the primary site for Cl- chemisorption and a protective layer for NFI as an ohmic contact. Galvanostatic electrolysis of NH4+-laden synthetic wastewater demonstrated that NFI/TiO2 not only achieves quasi-stoichiometric NH4+-to-N-2 conversion, but also enhances H-2 generation efficiency with minimal competing reactions such as reduction of dissolved oxygen and reactive chlorine. The scaled-up WEC with NFI/TiO2 was demonstrated for electrolysis of toilet wastewater.

关键词： Wastewater electrolysis cell Ir-doped NiFe2O4 Reactive chlorine species Decentralized H-2 production On-site wastewater treatment

Local Meteorological and Synoptic Characteristics of Fogs Formed over Incheon International Airport in the West Coast of Korea

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2010年第4期27卷 761-776页

作者： chang Ki kim Seong Soo YUM Department of Atmospheric Sciences Yonsei University 134 Shinchon-dong Seodaemun-gu Seoul 120-749 Korea

Fogs observed over Incheon international airport （IIA） in the west coast of Korea from January 2002 to August 2006 are classified into categories of coastal fog, cold sea fog, and warm sea fog based on the areal extent of the fogs and the difference between the air temperature （T ） and the SST, i.e., cold sea fog if TSST = T -SST 〉 0~0C and warm sea fog if TSST 〈 0~0C. The numbers of coastal, cold, and warm sea fog cases are 64, 26, and 9. Coastal fogs form most frequently in winter, while cold sea fogs occur mostly in summer and warm sea fogs are observed from January to May but not in November and December. On average the air gets colder by 1.6~0C during the three hours leading up to the coastal fog formation, and an additional cooling of 1.1~0C occurs during the fog. The change in the dew point temperature （T_d） is minimal except during the fog （0.6~0C）. Decreases in T for the cold and warm sea fogs are relatively smaller. The average Td is higher than SST during the cold sea fog periods but this T_d is more than 4~0C higher than that for the corresponding non-fog days, suggesting that cold sea fogs be formed by the cooling of already humid air （i.e., T_d〉SST）. Increases of T_d are significant during the warm sea fog periods （1.4~0C）, implying that effcient moisture supply is essential to warm sea fog formation. Four major synoptic patterns are identified in association with the observed fogs. The most frequent is a north Pacific high that accounts for 38% of cases. Surface or upper inversions are present in 77%, 69%, and 81% of the fog periods for coastal, cold, and warm sea fogs, respectively.

关键词： costal fogs sea fogs west coast of Korea meteorological and synoptic characteristics

Surface properties of Al-doped ZnO thin film before and after CF_4/Ar plasma etching

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2022年第7期24卷 194-200页

作者： Young-Hee JOO Gwan-Ha kim Doo-Seung UM chang-Il kim School of Electrical and Electronics Engineering Chung-Ang UniversitySeoul 06974Republic of Korea Department of Semiconductor Materials and Applications Korea PolytechnicSeongnam 13122Republic of Korea Department of Electrical Engineering Sejong UniversitySeoul 05006Republic of Korea

Al-doped ZnO(AZO) is considered as an alternative to transparent conductive oxide *** and achieving a stable surface are important challenges in the development and optimization of dry etching processes, which must be overcome for the application of AZO in various devices. Therefore, in this study, the etch rate and surface properties of an AZO thin film after plasma etching using the adaptive coupled plasma system were investigated. The fastest etch rate was achieved with a CF_(4)/Ar ratio of 50:50 sccm. Regardless of the ratio of CF_(4) to Ar,the transmittance of the film in the visible region exceeded 80%. X-ray photoelectron spectroscopy analysis of the AZO thin film confirmed that metal-F bonding persists on the surface after plasma etching. It was also shown that F eliminates O vacancies. Consequently, the work function and bandgap energy increased as the ratio of CF-4 increased. This study not only provides information on the effect of plasma on AZO thin film, but identifies the cause of changes in the device characteristics during device fabrication.

关键词： Al-doped ZnO plasma etching F-based plasma surface characteristics X-ray photoelectron spectroscopy ultraviolet photoelectron spectroscopy

Efficient electron extraction of SnO_(2) electron transport layer for lead halide perovskite solar cell

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2020年第1期6卷 836-843页

作者： Junu kim Kwang S.kim chang Woo Myung Center for Superfunctional Materials Department of PhysicsSchool of Natural ScienceUlsan National Institute of Science and Technology(UNIST)Ulsan 44919Korea Center for Superfunctional Materials Department of ChemistrySchool of Natural ScienceUlsan National Institute of Science and Technology(UNIST)Ulsan 44919Korea

SnO_(2) electron transport layer(ETL)has been spotlighted with its excellent electron extraction and stability over TiO_(2) ETL for perovskite solar cells(PSCs),rapidly approaching the highest power conversion ***,how... 详细信息

关键词： ETL layer perovskite

Investigation of operation and degradation mechanisms in ZnTeSe blue quantum-dot light-emitting diodes by identifying recombination zone

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第7期17卷 6527-6533页

作者： Oul Cho Sujin Park Hogeun chang Jiwhan kim Jaekwon kim Sungwoo kim Taehyung kim Jeonghun Kwak Department of Electrical and Computer Engineering Inter-university Semiconductor Research Centerand Soft Foundry InstituteSeoul National UniversitySeoul 08826Republic of Korea Material Research Center Samsung Advanced Institute of TechnologySuwonGyeonggi-do 16419Republic of Korea

ZnTeSe quantum dots(QDs),recognized as promising eco-friendly blue electroluminescent emitters,remain under-explored in light-emitting diode(LED)***,to elucidate the operation and degradation mechanisms of ZnTeSe blue QD-LEDs,stacked ZnTeSe QD layers with discernable luminescence are designed by varying Te doping concentrations,and the recombination zones(RZs)of the blue QD-LEDs are *** RZs are identified near the hole-transport layer(HTL),confirmed by angular-dependent electroluminescence measurements and optical *** addition,in order to investigate carrier dynamics in the process of recombination,the transient electroluminescence(tr-EL)signals of the dichromatic QD-LEDs are *** a result,it is inferred that the RZ initially formed near the electron-transport layer(ETL)due to the high injection barriers of ***,due to the fast electron mobility,the RZ shifts toward the HTL as the operating current *** the device lifetime tests,the RZ remains stationary while the photoluminescence(PL)corresponding to the RZ undergoes a substantial decrease,indicating that the degradation is accelerated by the concentrated *** this study contributes to a deeper understanding of the operational mechanisms of ZnTeSe blue QD-LEDs.

关键词： quantum dots light-emitting diodes degradation recombination zones carrier dynamics

Optimal design considering structural efficiency of compressed natural gas fuel storage vessels for automobiles

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 199-204页

作者： Myung-chang KANG Hyung Woo LEE Chul kim National Core Research Center for Hybrid Materials Solution Pusan National University Research Institute of Mechanical Technology Pusan National University

The shape and thickness of the dome were investigated with the aim of optimizing the type II CNG storage vessels by using a finite element analysis technique. The thickness of the liners and reinforcing materials was optimized based on the requirement of the cylinder and dome parts. In addition, the shape of the dome, which is most suitable for type lI CNG storage vessels, was proposed by a process of review and analysis of various existing shapes, and the minimum thickness was established in this sequence： metal liners, composite materials and dome parts. Therefore, the new proposed shape products give a mass reduction of 4.8 kg（5.1%）

关键词： CNG fuel storage vessel mechanical property dome part bursting structural analysis

A NUMERICAL ANALYSIS OF THE VENTILATION PERFORMANCE FOR DIFFERENT VENTILATION STRATEGIES IN A SUBWAY TUNNEL

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2012年第2期24卷 193-201页

作者： HUANG Yuan-dong LI Chan kim chang Nyung School of Environment and Architecture University of Shanghai for Science and Technology China College of Engineering Kyung Hee University Yongin 449-701 Korea Graduate School Kyung Hee University Yongin 449-701 Korea Industrial Liaison Research Institute Kyung Hee University Yongin 449-701 Korea

An unsteady three-dimensional analysis of the ventilation performance is carried out for different ventilation strategies to find out a ventilation method with a high performance in a subway *** natural ventilation performance associated with a train-induced air flow in a subway tunnel is *** dynamic layering method is used to consider the moving boundary of a train in the current CFD *** geometries of the modeled tunnel and the subway train are partially based on those of the Seoul *** effects of the structure of the ventilation duct and the geometry of the partitions on the ventilation performance are *** results show that the combined ventilation ducts （to be designed）,and the partitioning blocks installed along the middle of tunnel （already in existences） are helpful for air *** study can provide some guidance for the design of ventilation ducts in a subway system.

关键词： ventilation performance subway tunnel train-induced air flow natural ventilation duct numerical analysis