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Korea Institute of Sport Science:Past,Present and Future
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作者 Dong-Sik Chung 《中国体育科技》 CSSCI 北大核心 2009年第1期14-18,共5页
Introduction Korea Institute of Sport Science (KISS,formerly named as Korea Sport Science Institute:KSSI) was established on December 29th,1980 to perform research and provide support for better performance of the na... Introduction Korea Institute of Sport Science (KISS,formerly named as Korea Sport Science Institute:KSSI) was established on December 29th,1980 to perform research and provide support for better performance of the national athletes.KISS had clear objective of supporting scientifi c training of national athletes for successful hosting of 1986 Asian Games and 1988 Olympics,both were to be held in Seoul,Korea. The objective was successfully achieved with strong support from the government. 展开更多
关键词 运动员 体育训练 训练方法 科学训练
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Recent trends in the epidemiology and clinical outcomes of inflammatory bowel disease in South Korea,2010-2018
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作者 Seulji Kim Hyun Jung Lee +6 位作者 Seung Woo Lee Sanghyun Park Seong-Joon Koh Jong Pil Im Byeong Gwan Kim Kyung-Do Han Joo Sung Kim 《World Journal of Gastroenterology》 SCIE CAS 2024年第9期1154-1163,共10页
BACKGROUND Inflammatory bowel disease(IBD)was previously regarded as a Western disease;however,its incidence is increasing in the East.The epidemiology of IBD in Asia differs significantly from the patterns in the Wes... BACKGROUND Inflammatory bowel disease(IBD)was previously regarded as a Western disease;however,its incidence is increasing in the East.The epidemiology of IBD in Asia differs significantly from the patterns in the West.AIM To comprehensively investigate the epidemiology of IBD in South Korea,inclu-ding its incidence,prevalence,medication trends,and outcomes.METHODS We analyzed claims data from the Health Insurance Review and Assessment Service and Rare and Intractable Diseases(RIDs),operated by the National Health Insurance Service of South Korea.Patients with IBD were identified based on the International Classification of Diseases,Tenth Revision,and RID diagnostic codes for Crohn’s disease(CD)and ulcerative colitis(UC)from 2010 to 2018.RESULTS In total,14498 and 31409 patients were newly diagnosed with CD and UC,respectively,between 2010 and 2018.The annual average incidence of CD was 3.11 cases per 105 person-years,and that of UC was 6.74 cases per 10^(5) person-years.Since 2014,the incidence rate of CD has been stable,while that of UC has steadily increased,shifting the peak age group from 50-year-olds in 2010 to 20-year-olds in 2018.The CD and UC prevalence increased consistently over the study period;the use of 5-aminosali-cylates and corticosteroids gradually decreased,while that of immunomodulators and biologics steadily increased in both CD and UC.The clinical outcomes of IBD,such as hospitalization and surgery,decreased during the study period.CONCLUSION The CD incidence has been stable since 2014,but that of UC has increased with a shift to a younger age at peak incidence between 2010 and 2018.IBD clinical outcomes improved over time,with increased use of immunomodu-lators and biologics. 展开更多
关键词 Inflammatory bowel disease Crohn’s disease Ulcerative colitis INCIDENCE PREVALENCE
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Potential industrial applications of photo/electrocatalysis: Recent progress and future challenges 被引量:2
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作者 Jinhao Li Jing Ren +8 位作者 Shaoquan Li Guangchao Li Molly Meng-Jung Li Rengui Li Young Soo Kang Xiaoxin Zou Yong Luo Bin Liu Yufei Zhao 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第5期859-876,共18页
Nowadays,the rapid development of the social economy inevitably leads to global energy and environmental crisis.For this reason,more and more scholars focus on the development of photocatalysis and/or electrocatalysis... Nowadays,the rapid development of the social economy inevitably leads to global energy and environmental crisis.For this reason,more and more scholars focus on the development of photocatalysis and/or electrocatalysis technology for the advantage in the sustainable production of high-value-added products,and the high efficiency in pollutants remediation.Although there is plenty of outstanding research has been put forward continuously,most of them focuses on catalysis performance and reaction mechanisms in laboratory conditions.Realizing industrial application of photo/electrocatalytic processes is still a challenge that needs to be overcome by social demand.In this regard,this review comprehensively summarized several explorations in thefield of photo/electrocatalytic reduction towards potential industrial applications in recent years.Special attention is paid to the successful attempts and the current status of photo/electrocatalytic water splitting,carbon dioxide conversion,resource utilization from waste,etc.,by using advanced reactors.The key problems and challenges of photo/electrocatalysis in future industrial practice are also discussed,and the possible development directions are also pointed out from the industry view. 展开更多
关键词 PHOTOCATALYSIS ELECTROCATALYSIS Industrial applications H2 economy
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Significantly Improved High-Temperature Energy Storage Performance of BOPP Films by Coating Nanoscale Inorganic Layer 被引量:2
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作者 Tiandong Zhang Hainan Yu +5 位作者 Young Hoon Jung Changhai Zhang Yu Feng Qingguo Chen Keon Jae Lee Qingguo Chi 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第2期30-38,共9页
Biaxially oriented polypropylene(BOPP)is one of the most commonly used commercial capacitor films,but its upper operating temperature is below 105℃due to the sharply increased electrical conduction loss at high tempe... Biaxially oriented polypropylene(BOPP)is one of the most commonly used commercial capacitor films,but its upper operating temperature is below 105℃due to the sharply increased electrical conduction loss at high temperature.In this study,growing an inorganic nanoscale coating layer onto the BOPP film's surface is proposed to suppress electrical conduction loss at high temperature,as well as increase its upper operating temperature.Four kinds of inorganic coating layers that have different energy band structure and dielectric property are grown onto the both surface of BOPP films,respectively.The effect of inorganic coating layer on the high-temperature energy storage performance has been systematically investigated.The favorable coating layer materials and appropriate thickness enable the BOPP films to have a significant improvement in high-temperature energy storage performance.Specifically,when the aluminum nitride(AIN)acts as a coating layer,the AIN-BOPP-AIN sandwich-structured films possess a discharged energy density of 1.5 J cm^(-3)with an efficiency of 90%at 125℃,accompanying an outstandingly cyclic property.Both the discharged energy density and operation temperature are significantly enhanced,indicating that this efficient and facile method provides an important reference to improve the high-temperature energy storage performance of polymer-based dielectric films. 展开更多
关键词 coating layer energy storage interfacial barrier polymer films
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Ecological evaluation of marine macroalgal communities on five islands of Korea in the Yellow Sea
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作者 Su Jin Han Jae-Gil Jang +2 位作者 Hyun-Jung Kim Tae-Ho Seo Joo Myun Park 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第6期49-56,共8页
Macroalgae have long been used as biological indicators of marine ecosystem health worldwide due to their ecological importance and sensitivity to environmental stress.A number of previous studies have utilized macroa... Macroalgae have long been used as biological indicators of marine ecosystem health worldwide due to their ecological importance and sensitivity to environmental stress.A number of previous studies have utilized macroalgal communities in monitoring surveys of environmental conditions.This study examined the characteristics and patterns of marine macroalgal communities in the Yellow Sea off the western coast of Korea.Macroalgae were analyzed for the number of species,biomass,and coverage ratio by macroalgal type.During the study period,82 macroalgal species(10 green algae,17 brown algae,and 55 red algae)were identified at the five study sites,with the highest number of species found at Gwanrido and Uido(both containing 41 species)and the lowest at Daeijakdo(27 species).The average biomass(via dry weight)was 98.63 g/m^(2),consisting of green algae(8.39 g/m^(2)),brown algae(35.08 g/m^(2)),and red algae(55.16 g/m^(2)).The dominant macroalgae species in terms of biomass were Corallina pilulifera,Sargassum thunbergii,and Ulva australis in the intertidal zones,and Botryocladia wrightii and Gelidium elegans in the subtidal zones.Richness,evenness,and diversity indices based on the biomass of abundant species were 5.08,0.65,and 2.30,respectively,over the entire study area.Based on the evaluation of the environmental states by the community indices,overall,the Ecological Evaluation Index of macroalgae communities in the study area was marked as“Good-Moderate”,but was determined as“ModerateLow”at several sites during summer.The results can be a direct approach in the assessment of coastal habitats in which anthropogenic as well as climate change influences persist. 展开更多
关键词 MACROALGAE Yellow Sea ecological state groups ecological index Ecological Evaluation Index(EEI) community variable
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Surface engineering of ZnO electrocatalyst by N doping towards electrochemical CO_(2) reduction 被引量:1
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作者 Rohini Subhash Kanase Getasew Mulualem Zewdie +7 位作者 Maheswari Arunachalam Jyoti Badiger Suzan Abdelfattah Sayed Kwang-Soon Ahn Jun-Seok Ha Uk Sim Hyeyoung Shin Soon Hyung Kang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第1期71-81,I0002,共12页
The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-b... The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-based electrocatalyst was developed for use in gas-diffusion electrodes(GDE),and the effect of nitrogen(N)doping on the ECR activity of ZnO electrocatalysts was investigated.Initially,a ZnO nanosheet was prepared via the hydrothermal method,and nitridation was performed at different times to control the N-doping content.With an increase in the N-doping content,the morphological properties of the nanosheet changed significantly,namely,the 2D nanosheets transformed into irregularly shaped nanoparticles.Furthermore,the ECR performance of Zn O electrocatalysts with different N-doping content was assessed in 1.0 M KHCO_(3) electrolyte using a gas-diffusion electrode-based ECR cell.While the ECR activity increased after a small amount of N doping,it decreased for higher N doping content.Among them,the N:ZnO-1 h electrocatalysts showed the best CO selectivity,with a faradaic efficiency(FE_(CO))of 92.7%at-0.73 V vs.reversible hydrogen electrode(RHE),which was greater than that of an undoped Zn O electrocatalyst(FE_(CO)of 63.4%at-0.78 V_(RHE)).Also,the N:ZnO-1 h electrocatalyst exhibited outstanding durability for 16 h,with a partial current density of-92.1 mA cm^(-2).This improvement of N:ZnO-1 h electrocatalyst can be explained by density functional theory calculations,demonstrating that this improvement of N:ZnO-1 h electrocatalyst comes from(ⅰ)the optimized active sites lowering the free energy barrier for the rate-determining step(RDS),and(ⅱ)the modification of electronic structure enhancing the electron transfer rate by N doping. 展开更多
关键词 ZNO N-doped ZnO Gas-diffusion electrode CO Selectivity Electrochemical CO_(2)reduction
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Correction:Impact of Transition Metal Layer Vacancy on the Structure and Performance of P2 Type Layered Sodium Cathode Material 被引量:1
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作者 Orynbay Zhanadilov Sourav Baiju +7 位作者 Natalia Voronina Jun Ho Yu A-Yeon Kim Hun-Gi Jung Kyuwook Ihm Olivier Guillon Payam Kaghazchi Seung-Taek Myung 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第12期532-532,共1页
Following publication of the original article[1],the authors reported that the author Hun-Gi Jung should be affiliated as 3,4 and 5 instead of 4 and 5.The author’s name“A.-Yeon Kim”needed to be updated to“A-Yeon ... Following publication of the original article[1],the authors reported that the author Hun-Gi Jung should be affiliated as 3,4 and 5 instead of 4 and 5.The author’s name“A.-Yeon Kim”needed to be updated to“A-Yeon Kim”,removing the period.The correct author’s name and affiliation have been provided in this Correction.The original article[1]has been corrected. 展开更多
关键词 removing Transition IMPACT
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Stable operation of highly loaded pure Si-Fe anode under ambient pressure via carboxy silane-directed robust solid electrolyte interphase
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作者 Guntae Lim Dong Guk Kang +6 位作者 Hyeon Gyu Lee Yen Hai Thi Tran Kihun An Junghyun Choi Kwang Chul Roh Do Youb Kim Seung-Wan Song 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第7期568-576,共9页
Incorporation of higher content Si anode material beyond 5 wt% to Li-ion batteries(LIBs)is challenging,owing to large volume change,swelling,and solid electrolyte interphase(SEI)instability issues.Herein,a strategy of... Incorporation of higher content Si anode material beyond 5 wt% to Li-ion batteries(LIBs)is challenging,owing to large volume change,swelling,and solid electrolyte interphase(SEI)instability issues.Herein,a strategy of diacetoxydimethylsilane(DAMS)additive-directed SEI stabilization is proposed for a stable operation of Si-0.33FeSi_(2)(named as Si-Fe)anode without graphite,which provides siloxane inorganics and organics enrichment that compensate insufficient passivation of fluoroethylene carbonate(FEC)additive and reduce a dependence on FEC.Unprecedented stable cycling performance of highly loaded(3.5 mA h cm^(-2))pure Si-Fe anode is achieved with 2 wt%DAMS combined with 9 wt%FEC additives under ambient pressure,yielding high capacity 1270 mA h g^(-1)at 0.5 C and significantly improved capacity retention of 81% after 100 cycles,whereas short circuit and rapid capacity fade occur with FEC only additive.DAMS-directed robust SEI layer dramatically suppresses swelling and particles crossover through separator,and therefore prevents short circuit,demonstrating a possible operation of pure Si or Sidominant anodes in the next-generation high-energy-density and safe LIBs. 展开更多
关键词 High-energy Li-ion battery Pure Si-Fe anode without graphite Silane additive SEI layer Suppressed swelling
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The Accuracy Levels of Vehicle Detectors Commonly Used in Korea Based on the Results of Quality Certification Test
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作者 Sang Hyup Lee 《Journal of Traffic and Transportation Engineering》 2023年第4期172-178,共7页
The Ministry of Land, Infrastructure and Transport of Korea introduced the ITS system performance evaluation about six and a half years ago. The main purpose is to make sure that accurate and reliable real-time traffi... The Ministry of Land, Infrastructure and Transport of Korea introduced the ITS system performance evaluation about six and a half years ago. The main purpose is to make sure that accurate and reliable real-time traffic data are collected from the ITS system installed. There are three types of performance evaluations, which are Quality Certification Test, Pre-Delivery Test and Periodic Check in Operation. In this paper the accuracy levels of vehicle detectors commonly used in Korea are analyzed based on the results of quality certification tests conducted during 2008-2012. The test items consist of volume, speed and occupancy. The analysis shows that loop detectors have the best levels of accuracy in all three test items and their levels of accuracy have been steady. Video image detectors do not have so good levels of accuracy as loop detectors, but the levels of accuracy have improved as time passes. Radar detectors do not have good levels of accuracy. However, their levels of accuracy have improved as time passes. The last vehicle detectors, geomagnetism detectors have the worst accuracy in the occupancy item. 展开更多
关键词 Performance evaluation accuracy level vehicle detector quality certification test
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Boosted Lithium-Ion Transport Kinetics in n-Type Siloxene Anodes Enabled by Selective Nucleophilic Substitution of Phosphorus
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作者 Se In Kim Woong-Ju Kim +1 位作者 Jin Gu Kang Dong-Wan Kim 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第10期618-637,共20页
Doped two-dimensional(2D)materials hold significant promise for advancing many technologies,such as microelectronics,optoelectronics,and energy storage.Herein,n-type 2D oxidized Si nanosheets,namely n-type siloxene(n-... Doped two-dimensional(2D)materials hold significant promise for advancing many technologies,such as microelectronics,optoelectronics,and energy storage.Herein,n-type 2D oxidized Si nanosheets,namely n-type siloxene(n-SX),are employed as Li-ion battery anodes.Via thermal evaporation of sodium hypophosphite at 275℃,P atoms are effectively incorporated into siloxene(SX)without compromising its 2D layered morphology and unique Kautsky-type crystal structure.Further,selective nucleophilic substitution occurs,with only Si atoms being replaced by P atoms in the O_(3)≡Si-H tetrahedra.The resulting n-SX possesses two delocalized electrons arising from the presence of two electron donor types:(i)P atoms residing in Si sites and(ii)H vacancies.The doping concentrations are varied by controlling the amount of precursors or their mean free paths.Even at 2000 mA g^(-1),the n-SX electrode with the optimized doping concentration(6.7×10^(19) atoms cm^(-3))delivers a capacity of 594 mAh g^(-1) with a 73%capacity retention after 500 cycles.These improvements originate from the enhanced kinetics of charge transport processes,including electronic conduction,charge transfer,and solid-state diffusion.The approach proposed herein offers an unprecedented route for engineering SX anodes to boost Li-ion storage. 展开更多
关键词 Li-ion battery Two-dimensional N-type siloxene Doping mechanism KINETICS
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Revealing the influence of in-situ formed LiCl on garnet/Li interface for dendrite-free solid-state batteries
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作者 Seoyoon Shin Jinuk Lee +1 位作者 Tae Ho Shin Seokhee Lee 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第5期394-403,共10页
Inadequate interfacial contact between lithium and solid-state electrolytes(SSEs)leads to elevated impedance and the growth of lithium dendrites,presenting significant obstacles to the practical viability of solid-sta... Inadequate interfacial contact between lithium and solid-state electrolytes(SSEs)leads to elevated impedance and the growth of lithium dendrites,presenting significant obstacles to the practical viability of solid-state batteries(SSBs).To ameliorate interfacial contact,optimizing the surface treatment of SSEs has been widely adopted.However,the formation of LiCl through acid treatment,an equally crucial factor impacting SSB performance,has received limited attention,leaving its underlying mechanism unclear.Our study aims to shed light on SSE characteristics following LiCl formation and the removal of Li_(2)CO_(3) through acid treatment.We seek to establish quantifiable links between SSE surface structure and SSB performance,focusing on interfacial resistance,current distribution,critical current density(CCD),and lithium deposition.The formation of LiCl,occurring as Li_(2)CO_(3) is removed through acid treatment,effectively mitigates lithium dendrite formation on SSE surfaces.This action inhibits electron injection and reduces the diffusion rate of Li atoms.Simultaneously,acid treatment transforms the SSE surface into a lithiophilic state by eliminating surface Li_(2)CO_(3).Consequently,the interfacial resistance between lithium and SSEs substantially decreases from 487.67 to 35.99Ωcm^(2) at 25°C.This leads to a notably high CCD of 1.3 mA cm^(-2) and a significantly extended cycle life of 1,000 h.Furthermore,in full SSBs incorporating LiCoO_(2)cathodes and acid-treated garnet SSEs,we observe exceptional cyclability and rate capability.Our findings highlight that acid treatment not only establishes a fundamental relationship between SSE surfaces and battery performance but also offers an effective strategy for addressing interfacial challenges in SSBs. 展开更多
关键词 Solid-statebatteries Acidtreatment Interfacial stability LICL Surface modification
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Modeling asymmetric fracture mechanics of Mg alloy wire in drawing process
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作者 Sunghoon Choi Jongwon Shin +1 位作者 Joung Sik Suh Dongchoul Kim 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第5期2057-2069,共13页
In this study,a numerical analysis was conducted on the ductile fracture of a 2-mm diameter Mg-1Zn-0.5Mn-0.5Sr-0.1Ca alloy wire during drawing.The hexagonally close-packed crystal structure of Mg alloys causes asymmet... In this study,a numerical analysis was conducted on the ductile fracture of a 2-mm diameter Mg-1Zn-0.5Mn-0.5Sr-0.1Ca alloy wire during drawing.The hexagonally close-packed crystal structure of Mg alloys causes asymmetric fracture behavior,especially in the compression region.The aim of this study is to develop a comprehensive damage model for Mg alloy wire that accurately predicts ductile fracture,with a focus on the compression region.A novel experimental method was introduced to measure the ductile fracture of Mg alloy wires under different stress states.The wire drawing process was simulated using the Generalized Incremental Stress-State dependent damage(GISSMO)Model and the Semi-Analytical Model for Polymers(SAMP)model.The damage model's prediction and the experimental results were found to be in excellent agreement,especially in determining crack initiation.Computational analysis established a safe zone diagram for die angle and reduction ratio,and experimental validation confirmed the feasibility of this approach.The proposed damage model can provide a practical and reliable analysis for optimizing the drawing process of Mg alloy wire. 展开更多
关键词 Mg alloy Wire drawing Finite element method Damage model Safe zone diagram
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Effect of characteristics and distribution of Mg_(17)Al_(12)precipitates on tensile and bending properties of high-Al-containing Mg alloys
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作者 Sumi Jo Gyo Myeong Lee +2 位作者 Jong Un Lee Young Min Kim Sung Hyuk Park 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第2期779-793,共15页
This study investigates the effect of characteristics and distribution of Mg_(17)Al_(12)precipitates on the uniaxial tensile and three-point bending properties of extruded Mg alloys containing high Al contents.The ext... This study investigates the effect of characteristics and distribution of Mg_(17)Al_(12)precipitates on the uniaxial tensile and three-point bending properties of extruded Mg alloys containing high Al contents.The extruded Mg–9Al–1Zn–0.3Mn(AZ91)alloy contains lamellar-structured Mg_(17)Al_(12)discontinuous precipitates along the grain boundaries,which are formed via static precipitation during natural air cooling.The extruded Mg–11Al–1Zn–0.3Mn(AZ111)alloy contains spherical Mg_(17)Al_(12)precipitates at the grain boundaries and inside the grains,which are formed via dynamic precipitation during extrusion.Due to inhomogeneous distribution of precipitates,the AZ111 alloy consists of two different precipitate regions:precipitate-rich region with numerous precipitates and finer grains and precipitate-scarce region with a few precipitates and coarser grains.The AZ111 alloy exhibits a higher tensile strength than the AZ91 alloy because its smaller grain size and more abundant precipitates result in stronger grain-boundary hardening and precipitation hardening effects,respectively.However,the tensile elongation of the AZ111 alloy is lower than that of the AZ91 alloy because the weak cohesion between the dynamic precipitates and the matrix facilitates the crack initiation and propagation.During bending,a macrocrack initiates on the outer surface of bending specimen in both alloys.The AZ111 alloy exhibits higher bending yield strength and lower failure bending strain than the AZ91 alloy.The bending specimens of the AZ91 alloy have similar bending formability,whereas those of the AZ111 alloy exhibit considerable differences in bending formability and crack propagation behavior,depending on the distribution and number density of precipitates in the specimen.In bending specimens of the AZ111 alloy,it is found that the failure bending strain(ε_(f,bending))is inversely proportional to the area fraction of precipitates in the outer zone of bending specimen(A_(ppt)),with a relationship ofε_(f,bending)=–0.1A_(ppt)+5.86. 展开更多
关键词 Mg–Al alloy EXTRUSION BENDING Precipitation Microstructure
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Chemical and mechanical properties of stainless, environment-friendly, and nonflammable Mg alloys (SEN alloys): A review
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作者 Jong Un Lee Hyun Ji Kim +5 位作者 Sang-Cheol Jin Ye Jin Kim Young Min Kim Bong Sun You Jun Ho Bae Sung Hyuk Park 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第3期841-872,共32页
This review article provides overall understanding of stainless,environment-friendly,and nonflammable Mg alloys(SEN alloys)recently developed at the Korea Institute of Materials Science.SEN alloys are produced by addi... This review article provides overall understanding of stainless,environment-friendly,and nonflammable Mg alloys(SEN alloys)recently developed at the Korea Institute of Materials Science.SEN alloys are produced by adding small amounts of Ca and Y(each<1 wt%)into commercial Mg–Al based alloys,resulting in exceptional ignition and corrosion resistances and impressive mechanical properties.Their main advantages of SEN alloys are as follows.(1)A dense multi-oxide layer of SEN alloys comprising MgO,CaO,and Y_(2)O_(3) impedes the outward dispersion of Mg vapor and the inward penetration of O_(2) during oxidation,thereby enhancing the oxidation and ignition resistances.(2)The presence of Ca-and Y-based second-phase particles in SEN alloys can enhance their corrosion resistance because Ca-containing particles prevent the spread of corrosion,and the replacement of Al-containing particles with less noble ones containing Y(e.g.,Al–Mn–Y or Al–Y particles)retards corrosion.(3)The addition of minor amounts of Ca and Y renders excellent mechanical properties due to improved strengthening effects.These enhanced properties are attributed to more pronounced dynamic recrystallization and grain refining behaviors caused by the second-phase particles during extrusion.(4)Despite the presence of various types of second-phase particles,the fatigue properties of SEN9 alloys are similar to those of commercial AZ91 alloys.(5)Simultaneous introduction of Ca and Y suppresses the formation of Mg17Al12 discontinuous precipitates during aging,leading to the enhanced elongation of aged SEN alloys.(6)Adding mischmetal into the SEN9 alloy leads to a six-fold enhancement in extrudability.Consequently,the studies conducted on SEN alloys demonstrate their excellent ignition and corrosion resistances and mechanical properties,which broaden the industrial applications of Mg alloys by addressing their inherent weaknesses. 展开更多
关键词 SEN magnesium alloy Corrosion resistance Ignition resistance Mechanical properties Extrudability.
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Practical operating flexibility of a bifunctional freestanding membrane for efficient anion exchange membrane water electrolysis across all current ranges
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作者 Hong-Jin Son Jeemin Hwang +4 位作者 Min Young Choi Seung Hee Park Jae Hyuk Jang Byungchan Han Sung Hoon Ahn 《Carbon Energy》 SCIE EI CAS CSCD 2024年第9期306-324,共19页
This study explores a symmetric configuration approach in anion exchange membrane(AEM)water electrolysis,focusing on overcoming adaptability challenges in dynamic conditions.Here,a rapid and mild synthesis technique f... This study explores a symmetric configuration approach in anion exchange membrane(AEM)water electrolysis,focusing on overcoming adaptability challenges in dynamic conditions.Here,a rapid and mild synthesis technique for fabricating fibrous membrane-type catalyst electrodes is developed.Our method leverages the contrasting oxidation states between the sulfur-doped NiFe(OH)2 shell and the metallic Ni core,as revealed by electron energy loss spectroscopy.Theoretical evaluations confirm that the S–NiFe(OH)_(2) active sites optimize free energy for alkaline water electrolysis intermediates.This technique bypasses traditional energy-intensive processes,achieving superior bifunctional activity beyond current benchmarks.The symmetric AEM water electrolyzer demonstrates a current density of 2 A cm^(-2) at 1.78 V at 60℃ in 1 M KOH electrolyte and also sustains ampere-scale water electrolysis below 2.0 V for 140 h even in ambient conditions.These results highlight the system's operational flexibility and structural stability,marking a significant advance-ment in AEM water electrolysis technology. 展开更多
关键词 AEM water electrolysis fibrous membrane iR correction free operational stability symmetric configuration
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Experimental and computational optimization of Prussian blue analogues as high-performance cathodes for sodium-ion batteries:A review
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作者 Gwangeon Oh Junghoon Kim +4 位作者 Shivam Kansara Hyokyeong Kang Hun-Gi Jung Yang-Kook Sun Jang-Yeon Hwang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第6期627-662,I0015,共37页
In this review,we discuss the electrochemical properties of Prussian blue(PB)for Na^(+)storage by combining structural engineering and electrolyte modifications.We integrated experimental data and density functional t... In this review,we discuss the electrochemical properties of Prussian blue(PB)for Na^(+)storage by combining structural engineering and electrolyte modifications.We integrated experimental data and density functional theory(DFT)in sodium-ion battery(SIB)research to refine the atomic arrangements and crystal lattices and introduce substitutions and dopants.These changes affect the lattice stability,intercalation,electronic and ionic conductivities,and electrochemical performance.We unraveled the intricate structure-electrochemical behavior relationship by combining experimental data with computational models,including first-principles calculations.This holistic approach identified techniques for optimizing PB and Prussian blue analog(PBA)structu ral properties for SIBs.We also discuss the tuning of electrolytes by systematically adjusting their composition,concentration,and additives using a combination of molecular dynamics(MD)simulations and DFT computations.Our review offers a comprehensive assessment of strategies for enhancing the electrochemical properties of PB and PBAs through structural engineering and electrolyte modifications,combining experimental insights with advanced computational simulations,and paving the way for next-generation energy storage systems. 展开更多
关键词 Prussian blue analogs(PBAs) Sodium ion batteries(SIBs) Structural engineering Electrolyte modifications Experiments Density functional theory(DFT)
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Effect of pre-twinning and heat treatment on formability of AZX311 Mg alloy
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作者 Mahesh Panchal Lalit Kaushik +3 位作者 Min-Seong Kim Ravi Kottan Renganayagalu Shi-Hoon Choi Jaiveer Singh 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第3期1154-1169,共16页
In this study,the effects of pre-strain-induced tensile twins(TTWs)and controlled heat treatment on the formability behavior of AZX311 Mg alloy sheets were investigated.A 4%compressive strain was applied to pre-strain... In this study,the effects of pre-strain-induced tensile twins(TTWs)and controlled heat treatment on the formability behavior of AZX311 Mg alloy sheets were investigated.A 4%compressive strain was applied to pre-strain the sheets using the in-plane compression(IPC)technique along the rolling direction(RD)to introduce TTWs.The pre-strained(PS)samples were subsequently heat-treated at 250℃,350℃,and 400℃ independently for 1 hr,and are termed as PSA1,PSA2,and PSA3,respectively.Erichsen cupping tests were conducted to assess the formability of the sheet samples under different initial conditions.The results showed that the PS sample heat-treated at 250℃ for 1hr exhibited a decrease in the Erichsen index(IE)compared to the as-rolled sample,whereas PSA2 and PSA3 samples showed an increase in IE values.Microtexture analysis revealed that most of the TTWs generated through pre-twinning were stable at 250℃;however,the twin volume fraction reduced to 41%at 350℃ compared to the PS samples due to enhanced thermal activity at that temperature.Furthermore,PSA2 samples showed severe grain coarsening in some areas of the sample,and the fraction of such grains increased in the PSA3 samples.The stretch formability(IE value)of PSA2 samples showed a 32.3%increase compared to the as-rolled specimens.Additionally,the analysis of the deformed specimen at failure under the Erichsen test indicated that considerable detwinning occurs in the PS and PSA1 samples,whereas dislocation slip activity dominates in the PSA2 and PSA3 samples during stretch forming.Apart from detwinning and dislocation slip,deformation twins were also observed in all samples after the Erichsen test.Thus,this work highlights the importance of texture control and its underlying mechanisms via pre-twinning followed by heat treatment and their impact on the room temperature(RT)stretch formability of AZX311 Mg alloy sheets. 展开更多
关键词 Mg alloys Pre-twinning Texture FORMABILITY EBSD.
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Amorphous BaTiO_(3) Electron Transport Layer for Thermal Equilibrium-Governed γ-CsPbl_(3) Perovskite Solar Cell with High Power Conversion Efficiency of 19.96%
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作者 Changhyun Lee Chanyong Lee +4 位作者 Kyungjin Chae Taemin Kim Seaeun Park Yohan Ko Yongseok Jun 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第3期291-302,共12页
Compared to organic-inorganic hybrid perovskites,the cesium-based allinorganic lead halide perovskite(CsPbI_(3))is a promising light absorber for perovskite solar cells owing to its higher resistance to thermal stress... Compared to organic-inorganic hybrid perovskites,the cesium-based allinorganic lead halide perovskite(CsPbI_(3))is a promising light absorber for perovskite solar cells owing to its higher resistance to thermal stress.Nonetheless,additional research is required to reduce the nonradiative recombination to realize the full potential of CsPbI_(3).Here,the diffusion of Cs ions participating in ion exchange is proposed to be an important factor responsible for the bulk defects inγ-CsPbI_(3)perovskite.Calculations based on first-principles density functional theory reveal that the[PbI_(6)]^(4-)octahedral tilt modifies the perovskite crystallographic properties inγ-CsPbI_(3),leading to alterations in its bandgap and crystal strain.In addition,by substituting amorphous barium titanium oxide(a-BaTiO_(3))for TiO_(2)as the electron transport layer,interfacial defects caused by imperfect energy levels between the electron transport layer and perovskite are reduced.High-resolution transmission electron microscopy and electron energy loss spectroscopy demonstrate that a-BaTiO_(3)forms entirely as a single phase,as opposed to Ba-doped TiO_(2)hybrid nanoclusters or separate domains of TiO_(2)and BaTiO_(3)phases.Accordingly,inorganic perovskite solar cells based on the a-BaTiO_(3)electron transport layer achieved a power conversion efficiency of 19.96%. 展开更多
关键词 amorphous BaTiO_(3) electron transport layer MOISTURE γ-CsPbI_(3)
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In-Depth Study of Potential-Based Routing and New Exploration of Its Scheduling Integration
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作者 Jihoon Sung Yeunwoong Kyung 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第9期2891-2911,共21页
Industrial wireless mesh networks(WMNs)have been widely deployed in various industrial sectors,providing services such as manufacturing process monitoring,equipment control,and sensor data collection.A notable charact... Industrial wireless mesh networks(WMNs)have been widely deployed in various industrial sectors,providing services such as manufacturing process monitoring,equipment control,and sensor data collection.A notable characteristic of industrial WMNs is their distinct traffic pattern,where the majority of traffic flows originate from mesh nodes and are directed towards mesh gateways.In this context,this paper adopts and revisits a routing algorithm known as ALFA(autonomous load-balancing field-based anycast routing),tailored specifically for anycast(one-to-one-of-many)networking in WMNs,where traffic flows can be served through any one of multiple gateways.In essence,the scheme is a hybrid-type routing strategy that leverages the advantages of both back-pressure routing and geographic routing.Notably,its novelty lies in being developed by drawing inspiration from another field,specifically from the movement of charges in an electrostatic potential field.Expanding on the previous work,this paper explores further in-depth discussions that were not previously described,including a detailed description of the analogy between an electrostatic system and a WMN system based on precise mapping perspectives derived from intensive analysis,as well as discussions on anycast,numerical methods employed in devising the ALFA scheme,its characteristics,and complexity.It is worth noting that this paper addresses these previously unexplored aspects,representing significant contributions compared to previous works.As a completely new exploration,a new scheduling strategy is proposed that is compatible with the routing approach by utilizing the potential-based metric not only in routing but also in scheduling.This assigns higher medium access priority to links with a larger potential difference.Extensive simulation results demonstrate the superior performance of the proposed potential-based joint routing and scheduling scheme across various aspects within industrial WMN scenarios. 展开更多
关键词 Potential-based routing potential differential scheduling industrial wireless mesh networks
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A review of understanding electrocatalytic reactions in energy conversion and energy storage systems via scanning electrochemical microscopy
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作者 Jihye Park Jong Hwan Lim +4 位作者 Jin-Hyuk Kang Jiheon Lim Ho Won Jang Hosun Shin Sun Hwa Park 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第4期155-177,共23页
To address climate change and promote environmental sustainability,electrochemical energy conversion and storage systems emerge as promising alternative to fossil fuels,catering to the escalating demand for energy.Ach... To address climate change and promote environmental sustainability,electrochemical energy conversion and storage systems emerge as promising alternative to fossil fuels,catering to the escalating demand for energy.Achieving optimal energy efficiency and cost competitiveness in these systems requires the strategic design of electrocatalysts,coupled with a thorough comprehension of the underlying mechanisms and degradation behavior occurring during the electrocatalysis processes.Scanning electrochemical microscopy(SECM),an analytical technique for studying surface electrochemically,stands out as a powerful tool offering electrochemical insights.It possesses remarkable spatiotemporal resolution,enabling the visualization of the localized electrochemical activity and surface topography.This review compiles crucial research findings and recent breakthroughs in electrocatalytic processes utilizing the SECM methodology,specifically focusing on applications in electrolysis,fuel cells,and metal–oxygen batteries within the realm of energy conversion and storage systems.Commencing with an overview of each energy system,the review introduces the fundamental principles of SECM,and aiming to provide new perspectives and broadening the scope of applied research by describing the major research categories within SECM. 展开更多
关键词 Scanning electrochemical microscopy ELECTROCATALYST ELECTROCATALYSIS Water splitting Fuel cell Metal-oxygen battery
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