检索结果-南通市图书馆

Enhancement of magnetic properties of hot pressed/die-upset Dy-free Nd-Fe-B magnets with Cu/Nd coating by wet process

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2020年第1期39卷 48-54页

作者： Jeehye kwon Dajeong Lee Dayoung Yoo Seongkyu Park Hee-Ryoung Cha hae-woong kwon Junggoo Lee Dongyun Lee Department of Advanced Circuit Interconnection Pusan National UniversityBusan46241Republic of Korea Department of Nano Fusion Technology Pusan National UniversityBusan46241Republic of Korea Powder and Ceramics Department Korea Institute of Machinery and MaterialsChangwon51508Republic of Korea Department of Materials Science and Engineering Pukyong National UniversityBusan48513Republic of Korea Department of Nanoenergy Engineering Pusan National UniversityBusan46241Republic of Korea

A grain boundary diffusion process(GBDP)was adopted to improve magnetic properties of Dy-free highly coercive Nd-Fe-B permanent magnet by coating thin layers of Nd and Cu in grain *** GBDP of Nd and Cu,Nd and Cu were coated by wet process,e.g.,electrochemical and electroless on Nd-Fe-B magnets,which was fabricated by hot-deformed/die-upset with meltspun *** treatment was performed for 20 min at 600℃followed by several different cooling *** cooling conditions after heat treatment were varied to understand distribution and micros tructural effects of Nd and Cu species in grain *** coercivity increased from 1.565 to 1.637 T in oil cooling rate but remanence decreased,while remanence jumped with little decrease in coercivity in furnace *** tructure analyses suggested that the coercivity was closely related to the cooling rate as well as distribution of *** mechanism of coercivity enhancement due to the cooling rate was discussed based on the results presented here and those in the literature.

关键词： Magnetic materials Electrochemical deposition Diffusion Scanning electron microscopy Coercivity

Towards high-performance and robust anion exchange membranes(AEMs)for water electrolysis:Super-acid-catalyzed synthesis of AEMs

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第6期93卷 478-510,I0012页

作者： Geun woong Ryoo Sun Hwa Park Ki Chang kwon Jong Hun Kang Ho Won Jang Min Sang kwon Department of Materials Science and Engineering Research Institute of Advanced Materials(RIAM)Seoul National UniversitySeoul 08826Republic of Korea Interdisciplinary Materials Measurement Institute Korea Research Institute of Standards and Science(KRISS)Daejeon 34113Republic of Korea Department of Chemical and Biological Engineering and Institute of Chemical ProcessSeoul National UniversitySeoul 08826Republic of Korea Department of Applied Measurement Science University of Science and TechnologyDaejeon 34113Republic of Korea

The increasing demand for hydrogen energy to address environmental issues and achieve carbon neutrality has elevated interest in green hydrogen production,which does not rely on fossil *** various hydrogen production technologies,anion exchange membrane water electrolyzer(AEMWE)has emerged as a next-generation technology known for its high hydrogen production efficiency and its ability to use non-metal ***,this technology faces significant challenges,particularly in terms of the membrane durability and low ionic *** address these challenges,research efforts have focused on developing membranes with a new backbone structure and anion exchange groups to enhance durability and ionic ***,the super-acid-catalyzed condensation(SACC)synthesis method stands out due to its user convenience,the ability to create high molecular weight(MW)polymers,and the use of oxygen-tolerant organic *** the synthesis of anion exchange membranes(AEMs)using the SACC method began in 2015,and despite growing interest in this synthesis approach,there remains a scarcity of review papers focusing on AEMs synthesized using the SACC *** review covers the basics of SACC synthesis,presents various polymers synthesized using this method,and summarizes the development of these polymers,particularly their building blocks including aryl,ketone,and anion exchange *** systematically describe the effects of changes in the molecular structure of each polymer component,conducted by various research groups,on the mechanical properties,conductivity,and operational stability of the *** review will provide insights into the development of AEMs with superior performance and operational stability suitable for water electrolysis applications.

关键词： Green hydrogen production Water electrolysis Anion exchange membrane water electrolyzer(AEMWE) Anion exchange membranes(AEMs) Super-acid-catalyzed condensation(SACC)

Stoichiometric Ti3C2Tx Coating for Inhibiting Dendrite Growth in Anode-Free Lithium Metal Batteries

在线全文

学校读者我要写书评

暂无评论

Energy & Environmental Materials 2024年第4期7卷 153-162页

作者： Xiangrong Zeng Manmatha Mahato woong Oh Hyunjoon Yoo Van Hiep Nguyen Saewoong Oh Geetha Valurouthu Soon-Ki Jeong Chi Won Ahn Yury Gogotsi Il-kwon Oh National Creative Research Initiative for Functionally Antagonistic Nano-Engineering Department of Mechanical Engineering Korea Advanced Institute of Science and Technology (KAIST) Department of Materials Science & Engineering and A. J. Drexel Nanomaterials Institute Drexel University Department of Energy Engineering Soonchunhyang University National Nanofab Center (NNFC) Korea Advanced Institute of Science and Technology (KAIST)

Lithium metal batteries (LMBs) and anode-free LMBs (AFLMBs) present a solution to the need for batteries with a significantly superior theoretical energy ***,their adoption is hindered by low Coulombic efficiency (CE) and rapid capacity fading,primarily due to the formation of unstable solid electrolyte interphase (SEI) layer and Li dendrite growth as a result of uneven Li plating.

关键词： anode-free lithium metal batteries stoichiometric MXene solid electrolyte interphase surface terminations

Surgical Repair of Ventricular Septal Defect in Neonates: Indications and Outcomes

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Congenital Heart Disease 2024年第1期19卷 69-83页

作者： Jae Hong Lee Sungkyu Cho Jae Gun Kwak Hye Won kwon woong-Han Kim Mi Kyoung Song Sang-Yun Lee Gi Beom Kim Eun Jung Bae Department of Thoracic and Cardiovascular Surgery Research Institute for Convergence of Biomedical Science and TechnologyPusan National University Yangsan HospitalYangsanKorea Department of Thoracic and Cardiovascular Surgery Seoul National University Children’s HospitalSeoulKorea Department of Pediatrics Seoul National University Children’s HospitalSeoulKorea

Background:The optimal surgical timing and clinical outcomes of ventricular septal defect(VSD)closure in neo-nates remain *** aimed to evaluate the clinical outcomes of VSD closure in neonates(age≤30 days).Methods:We retrospectively reviewed 50 consecutive neonates who underwent VSD closure for isolated VSDs between August 2003 and June *** for the procedure included congestive heart failure/failure to thrive and pulmonary *** adverse events(MAEs)were deﬁned as the composite of all-cause mortality,reoperation,persistent atrioventricular block,and signiﬁcant(≥grade 2)valvular ***:The median age and body weight at operation were 26.0 days(interquartile range[IQR],18.8–28.3)and 3.7 kg(IQR,3.3–4.2),*** median follow-up duration was 110.4 months(IQR,56.8–165.0).Seven patients required preoperative respiratory support,andﬁve had signiﬁcant(≥grade 2)preoperative valvular *** early mortality occurred due to irreversible cardiogenic shock;no late mortality was *** reopera-tion was due to hemodynamically signiﬁcant residual VSD at 103.8 months *** overall survival,freedom from reoperation,and freedom from MAE at 15-years were 98.0%,96.3%,and 94.4%,***-operative mechanical ventilation was associated with a longer duration of postoperative mechanical ventilation(p<0.001)and a longer length of intensive care unit stay(p<0.001).Conclusions:VSD closure with favorable outcomes without morbidities is feasible even in ***,neonates requiring preoperative respiratory support may require careful postoperative management considering the long-term postoperative ***,surgical VSD closure might be indicated earlier in neonates with respiratory compromise.

关键词： Ventricular septal defect neonate early surgery neonatal surgery

Effect of Deformation Temperature on Microstructure and Mechanical Properties of AZ31 Mg Alloy Processed by Differential-Speed Rolling

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2015年第5期31卷 498-503页

作者： Mosab Kaseem Bong kwon Chung hae woong Yang Kotiba Hamad Young Gun Ko School of Materials Science and Engineering Yeungnam University

A differential-speed rolling(DSR) was applied to AZ31 magnesium alloy sample at different rolling temperatures of 473,523,573,and 623 K with 1-pass and 2-pass *** microstructural evolution and mechanical properties of the deformed samples were *** rolling temperature was found to be an important parameter affecting the microstructural *** DSR at 473 K,the microstructure was more homogeneous than that obtained after deformation by equal-speed rolling(ESR).The fully recrystallized microstructures were generated after DSR at 573 and 623 *** to mechanical properties,the yield strength(YS) and ultimate tensile strength(UTS) decreased monotonously with increasing rolling *** contrast,the elongation of the DSR-deformed samples was improved as the rolling temperature *** strain hardening exponent(n) calculated by Hollomon equation increased with increasing the rolling temperature,which would explain an increase in the uniform elongation.

关键词： Differential-speed rolling Magnesium alloy Mechani

Effect of Squeeze Cast Process Parameters on Fluidity of Hypereutectic Al-Si Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2008年第1期24卷 7-11页

作者： Jong-Kyu Baek hae-Wook kwon School of Materials Science and Engineering Yeungnam University Gyeongsan 712-749 Korea

The effects of processing variables on the fluidity of hypereutectic Al-Si alloy melt during squeeze casting were *** maximum fluidity of Al-16.0%Si alloy during squeeze casting was obtained under the applied pressure of 30 *** fluidity increased with *** fluidity increased with silicon content in the range from 12.0% to 20.0%.That was decreased respectively by eutectic modification and primary silicon refinement.

关键词： Squeeze casting Al-alloy Fluidity Melt treatment

Plastic anisotropy calculation of severely-deformed Al-Mg-Si alloy considering texture changes in electron backscatter diffraction

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2019年第7期35卷 1439-1443页

作者： I Putu Widiantara hae woong Yang Min Jun Kim Young Gun Ko Plasticity Control & Mechanical Modeling Lab. School of Materials Science & Engineering Yeungnam University

The investigation studied the plastic anisotropy of the severely-deformed Al-Mg-Si alloy by considering texture *** sample deformed via asymmetrical rolling under cross-shear condition was annealed at 598 K where recrystallization was in *** is found upon annealing that the intensity of Cube({001})was comparable to those of plane-strain components while the intensities of shear components remained constant despite their instabilities in the recrystallization *** annealing,the average Lankford value(r)of the present sample was close to a unity whereas the in-plane anisotropy(△r)decreased,resulting in nearly isotropic characteristics of Al-Mg-Si alloy.

关键词： Al-Mg-Si alloy Anisotropy Recrystallization Microstructures

Improving the electrochemical stability of AZ31 Mg alloy in a 3.5wt.%NaCl solution via the surface functionalization of plasma electrolytic oxidation coating

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2022年第5期10卷 1311-1325页

作者： Mosab Kaseem Tehseen Zehra Burak Dikici Ali Dafali hae woong Yang Young Gun Ko Department of Nanotechnology and Advanced Materials Engineering Sejong UniversitySeoul 05006Republic of Korea Department of Metallurgical and Materials Engineering Ataturk UniversityErzurum 25240Turkey Faculty of Sciences Oujda Department of ChemistryMohamed the First UniversityOujdaMorocco Pohang Institute of Metal Industry Advancement Pohang 37666Republic of Korea Materials Electrochemistry Group School of Materials Science and EngineeringYeungnam UniversityGyeongsan 38541Republic of Korea

The unique interactions between hexadecanoic acid(HA)and albumin(ALB)molecules on the surface of the porous layer of AZ31 Mg alloy were exploited to fabricate a novel hybrid composite film with excellent electrochemical stability in a 3.5 wt.%Na Cl ***,the inorganic layer(IL)obtained by plasma electrolytic oxidation of AZ31 Mg alloy in an alkaline-phosphate-WO_(3)electrolyte was soaked in an organic solution composed of ALB and HA for 10 and 24 h at 60℃.Although albumin and HA may coexist on the same surface of IL,the higher reactivity of ALB molecules would prevent the formation of a thick layer of *** donor-acceptor complexes formed due to the unique interactions between ALB and/or HA and IL surface would reduce the area exposed to the corrosive species which in turn would efficiently protect the substrate from *** porous structure of the IL would provide preferable sites for the physical and chemical locking triggered by charge-transfer phenomena,leading to the inhomogeneous nucleation and crystal growth of a flowery flakes-like organic *** calculations were performed to reveal the primary bonding modes between the ALB,HA,and IL and to assess the mechanistic insights into the formation of such novel hybrid composites.

关键词： Hybrid composite Coordination bond Albumin Fatty acid Porous layer Corrosion Theoretical approach

Study of material removal behavior on R-plane of sapphire during ultra-precision machining based on modified slip-fracture model

在线全文

学校读者我要写书评

暂无评论

Nanotechnology and Precision Engineering 2020年第3期3卷 141-155页

作者： Suk Bum kwon Aditya Nagaraj hae-Sung Yoon Sangkee Min Department of Mechanical Engineering University of Wisconsin-Madison1513 University AvenueMadisonWI 53706United States of America School of Aerospace and Mechanical Engineering Korea Aerospace University76 Hanggongdaehak-roDeogyang-guGoyang-siGyeonggi-do 10540Republic of Korea

In this paper, the modified slip/fracture activation model has been used in order to understand the mechanism of ductile-brittle transition on the R-plane of sapphire during ultra-precision machining by reflecting direction of resultant force. Anisotropic characteristics of crack morphology and ductility of machining depending on cutting direction were explained in detail with modified fracture cleavage and plastic deformation parameters. Through the analysis, it was concluded that crack morphologies were mainly determined by the interaction of multiple fracture systems activated while, critical depth of cut was determined by the dominant plastic deformation parameter. In addition to this, by using proportionality relationship between magnitude of resultant force and depth of cut in the ductile region, an empirical model for critical depth of cut was developed.

关键词： Ductile-brittle transition Crack morphology Single crystal sapphire Deformation mechanism Orthogonal cutting Ultra-precision machining