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| 1 | Phase stability and mechanical properties of wire+arc additively manufactured H13 tool steel at elevated temperatures显示文摘Wire+arc additive manufacturing(WAAM)is considered an innovative technology that can change the manufacturing landscape in the near future.WAAM offers the benefits of inexpensive initial system setup and a high deposition rate for fabricating medium-and large-sized parts such as die-casting tools.In this study,AISI H13 tool steel,a popular die-casting tool metal,is manufactured by cold metal transfer(CMT)-based WAAM and is then comprehensively analyzed for its microstructural and mechanical properties.Location-dependent phase combinations are observed,which could be explained by nonequilibrium thermal cycles that resulted from the layer-by-layer stacking mechanism used in WAAM.In addition,remelting and reheating of the layers reduces welding anomalies(e.g.,pores and voids).The metallurgical characteristics of the H13 strongly correlate with the mechanical properties.The combinations of phases at different locations of the additively manufactured part exhibit a periodic microhardness profile.Martensite,Retained Austenite,Ferrite,and Carbide phases are found in combination at different locations of the part based on the part’s temperature distribution during additive deposition.Moreover,the tensile properties at elevated temperatures(23℃,300℃,and 600℃)are comparable to those from other WAAM and additive manufacturing(AM)processes.The X-ray diffraction results verify that the microstructural stability of the fabricated parts at high temperatures would allow them to be used in high temperatures. | A.N.M.Tanvir Md.R.U.A hsan Gijeong Seo Brian Bates Chanho Lee Peter K.Liaw Mark Noakese Andrzej Nycz Changwook Ji Duck Bong Kim | 2021 | Journal of Materials Science & Technology2021，，8： | 5 |
| 2 | Avoiding heating interference and guided thermal conduction in stretchable devices using thermal conductive composite islands显示文摘The miniaturization and high integration of devices demand significant thermal management materials.Current technologies for the thermal management of electronics show some limitations in the case of multiple chip arrays.A device in multiple chip array is affected by heat from adjacent devices,along with thermal conductive composite.To address this problem,we present a nano composite of aligned boron nitride(BN)nanosheet islands with porous polydimethylsiloxane(PDMS)foam to have mechanical stability and non-thermal interference.The islands of tetrahedrally-structured BN in the composite have a high thermal conductivity of 1.219 W·m^(-1)·K^(-1) in the through-plane direction(11.234W·m^(-1)·K^(-1)in the in-plane direction)with 16 wt.%loading of BN.On the other hand,porous PDMS foam has a low thermal conductivity of 0.0328W·m^(-1)·K^(-1) in the through-plane direction at 70%porosity.Heat pathways are then formed only in the structured BN islands of the composite.The porous PDMS foam can be applied as a thermal barrier between structured BN islands to inhibit thermal interference in multiple device arrays.Furthermore,this composite can maintain selective thermal dissipation performance with 70%tensile strain.Another beauty of the work is that it could have guided heat dissipation by assembling of multiple layers which have high vertical thermal conductive islands,while inhibiting thermal interference.The selective heat dissipating composite can be applied as a heatsink for multiple chip arrays electronics. | Seung Ji Kang Haeleen Hong Chanho Jeong Ju Seung Lee Hyewon Ryu Jae-hun Yang Jong Uk Kim Yiel Jae Shin Tae-il Kim | 2021 | Nano Research2021，14，9： | 4 |
| 3 | Fatigue behavior of high-entropy alloys: A review显示文摘Fatigue failures cost approximately 4% of the United States' gross domestic product(GDP). The design of highly fatigue-resistant materials is always in demand. Different from conventional strategies of alloy design, high-entropy alloys(HEAs) are defined as materials with five or more principal elements, which could be solid solutions. This locally-disordered structure is expected to lead to unique fatigue-resistant properties. In this review, the studies of the fatigue behavior of HEAs during the last five years are summarized. The four-point-bending high-cycle fatigue coupled with statistical modelling, and the fatigue-crack-growth behavior of HEAs, are reviewed. The effects of sample defects and nanotwins-deformation mechanisms on four-point-bending high-cycle fatigue of HEAs are discussed in detail. The influence of stress ratio and temperature on fatigue-crack-growth characteristics of HEAs is also discussed. HEAs could exhibit comparable or greater fatigue properties, relative to conventional materials. Finally,the possible future work regarding the fatigue behavior of HEAs is suggested. | CHEN PeiYong LEE Chanho WANG Shao-Yu SEIFI Mohsen LEWANDOWSKI John J DAHMEN Karin A JIA HaoLing XIE Xie CHEN BiLin YEH Jien-Wei TSAI Che-Wei YUAN Tao LIAW Peter K | 2018 | Science China(Technological Sciences)2018，61，2： | 3 |
| 4 | New strategy for reversal tolerant anode for automotive polymer electrolyte fuel cell显示文摘Since the commercialization of the fuel cell electric vehicles (FCEVs), the polymer electrolyte membrane fuel cell system has been actively improved as a powertrain for ultimate environment-friendly vehicle. During the FCEV operation, various transient conditions such as start-up/shut-down and fuel starvation occur irregularly, which deteriorates the durability of the membrane electrode assembly. In particular, when fuel starvation occurs, the carbon support in the anode is oxidized within few minutes, thus the mitigation of this phenomenon is essential for securing the durability. This short review introduces the concept of reversal tolerant anode (RTA), which is a mitigation method using an oxygen evolution catalyst and reviews some previous reports. In addition, new approach for RTA suggested by authors recently, which is the replacement of Pt anode catalyst by multifunctional IrRu alloy catalyst that simultaneously exhibits the activities for the hydrogen oxidation reaction and the oxygen evolution reaction is introduced. | Chanho Pak Seung Woo Lee Chaekyung Baik Bong Ho Lee Dae Jong You Eunyoung You | 2019 | Chinese Chemical Letters2019，30，6： | 2 |
| 5 | Design of Encoder and Decoder for LDPC Codes Using Hybrid H-Matrix显示文摘 | LEE Chanho | 2005 | ETRI Journal2005，27，05： | 1 |
| 6 | High Performance Viterbi Decoder Using Modified Register Exchange Methods 显示文摘 | Jae Sun Han Tae Jin Kim Chanho Lee | 2004 | Proceedings of the 2004 International Symposium on Circuits and Systems2004，3，： | 1 |
| 7 | Multifunctional Ir–Ru alloy catalysts for reversal-tolerant anodes of polymer electrolyte membrane fuel cells显示文摘To address the problem of fuel starvation in fuel-cell electric vehicles,which causes cell voltage reversal and results in cell failure when repeated continuously,we developed a reversal-tolerant anode(RTA) to promote water oxidation in preference to carbon corrosion.Graphitized carbon-supported Ir-Ru alloys with different compositions are employed as RTA catalysts in an acidic polyol solution and are shown to exhibit composition-dependent average crystallite sizes of <5.33 nm.The adopted approach allows the generation of relatively well-dispersed Ir-Ru alloy nanoparticles on the carbon support without severe agglomeration.The activity of IrRu_(2)/C for the hydrogen oxidation reaction is 1.10 times that of the stateof-the-art Pt/C catalyst.Cell reversal testing by simulation of fuel starvation reveals that the durability of IrRu_(2)/C(~7 h) significantly exceeds that of the conventional Pt/C catalyst(~10 min) and is the highest value reported so far.Thus,the developed Ir-Ru alloy catalyst can be used to fabricate practical RTAs and replace Pt catalysts in the anodes of polymer electrolyte membrane fuel cells. | Seung Woo Lee Bongho Lee Chaekyung Baik Tae-Yang Kim Chanho Pak | 2021 | Journal of Materials Science & Technology2021，，1： | 0 |
| 8 | Zwitterion-assisted transition metal dichalcogenide nanosheets for scalable and biocompatible inkjet printing显示文摘Inkjet printing of two-dimensional(2D)transition metal dichalcogenide(TMD)nanosheets fabricated by liquid-phase exfoliation(LPE)allows simple,mass-producible,and low-cost photo-electronic devices.Many LPE processes involve toxic and environmentally hazardous solvents;however,dispersants have restricted the extent of applications of 2D-TMD inks.Herein,various 2D-TMD nanosheets,including MoS2,MoSe2,WS2,and WSe2,in addition to few-layered graphene,are inkjet-printed using a LPE process based on zwitterionic dispersants in water.Zwitterions with cationic and anionic species are water-soluble,while alkyl chain moieties associated with two ionic species adhere universally on the surface of TMD nanosheets,resulting in high throughput liquid exfoliation of the nanosheets.The zwitterion-assisted TMD nanosheets in water are successtully employed as an ink without the need for additives to adjust the viscosity and surface tension of the ink for use in an office inkjet printer;this gives rise to A4 scale,large-area inkjet-printed images on diverse substrates,such as metals,oxides,and polymer substrates patchable onto human skin.Combination with conductive graphene nanosheet inks allowed the development of mechanically flexible,biocompatible-printed arrays of photodetectors with pixelated MoSe2 channels on a paper exhibiting a photocurrent ON/OFF ratio of approximately 1038 and photocurrent switching of 500 ms. | Hyeokjung Lee Min Koo Chanho Park Madhumita Patel Hyowon Han Tae Hyun Park Pawan Kumar Won-Gun Koh Cheolmin Park | 2020 | Nano Research2020，13，10： | 0 |
| 9 | Strategy for Creating AR Applications in Static and Dynamic Environments Using SLAM-and Marker Detector-Based Tracking显示文摘Recently,simultaneous localization and mapping(SLAM)has received considerable attention in augmented reality(AR)libraries and applications.Although the assumption of scene rigidity is common in most visual SLAMs,this assumption limits the possibilities of AR applications in various real-world environments.In this paper,we propose a new tracking system that integrates SLAMwith amarker detection module for real-time AR applications in static and dynamic environments.Because the proposed system assumes that the marker is movable,SLAM performs tracking andmappingof the static scene except for themarker,andthemarker detector estimates the 3-dimensional pose of the marker attached to the dynamic object.We can place SLAM maps,cameras,and dynamic objects(markers)on the same coordinate system,and we can also accurately augment AR resources in real-time on both the static scene and dynamic objects simultaneously.Additionally,having a static map of the scene in advance has the advantage of being able to performtracking of static and dynamic environments with mapping disabled.In this paper,we evaluate whether the proposed tracking systemis suitable for AR applications and describe a strategy for creating AR applications in static and dynamic environments with a demonstration. | Chanho Park Hyunwoo Cho Sangheon Park Sung-Uk Jung Suwon Lee | 2022 | Computer Modeling in Engineering & Sciences2022，，4： | 0 |
| 10 | Electrolyte accessibility of non-precious-metal catalysts with different spherical particle sizes under alkaline conditions for oxygen reduction reaction显示文摘Fuel cells are one of the most competitive alternative energy sources because their theoretical efficiency is~15%higher than that of internal combustion engines (ICEs) and they are considered cleaner and safer.When fuel cells are used to replace ICEs in cars and energy conversion systems,the system efficiency increases;furthermore,the process becomes more environmentally-friendly because fuel cells produce electricity by using only hydrogen and oxygen,obtained by purifying atmospheric air by filtering out dust and pollutants.Hence,their final product is only water,instead of pollutants like carboFuel cells are one of the most competitive alternative energy sources because their theoretical efficiency is~15%higher than that of internal combustion engines (ICEs) and they are considered cleaner and safer.When fuel cells are used to replace ICEs in cars and energy conversion systems,the system efficiency increases;furthermore,the process becomes more environmentally-friendly because fuel cells produce electricity by using only hydrogen and oxygen,obtained by purifying atmospheric air by filtering out dust and pollutants.Hence,their final product is only water,instead of pollutants like carbon dioxide.n dioxide. | Jiyeon Lee Jong Gyeong Kim Chanho Pak | 2021 | Journal of Energy Chemistry2021，30，1： | 0 |
| 11 | Enhanced delivery of a low dose of aducanumab via FUS in 5×FAD mice,an AD model显示文摘Background:Aducanumab(Adu),which is a human IgG1 monoclonal antibody that targets oligomer and fibril forms of beta-amyloid,has been reported to reduce amyloid pathology and improve impaired cognition after administration of a high dose(10 mg/kg)of the drug in Alzheimer’s disease(AD)clinical trials.The purpose of this study was to investigate the effects of a lower dose of Adu(3 mg/kg)with enhanced delivery via focused ultrasound(FUS)in an AD mouse model.Methods:The FUS with microbubbles opened the blood-brain barrier(BBB)of the hippocampus for the delivery of Adu.The combined therapy of FUS and Adu was performed three times in total and each treatment was performed biweekly.Y-maze test,Brdu labeling,and immunohistochemical experimental methods were employed in this study.In addition,RNA sequencing and ingenuity pathway analysis were employed to investigate gene expression profiles in the hippocampi of experimental animals.Results:The FUS-mediated BBB opening markedly increased the delivery of Adu into the brain by approximately 8.1 times in the brains.The combined treatment induced significantly less cognitive decline and decreased the level of amyloid plaques in the hippocampi of the 5×FAD mice compared with Adu or FUS alone.Combined treatment with FUS and Adu activated phagocytic microglia and increased the number of astrocytes associated with amyloid plaques in the hippocampi of 5×FAD mice.Furthermore,RNA sequencing identified that 4 enriched canonical pathways including phagosome formation,neuroinflammation signaling,CREB signaling and reelin signaling were altered in the hippocami of 5×FAD mice receiving the combined treatment.Conclusion:In conclusion,the enhanced delivery of a low dose of Adu(3 mg/kg)via FUS decreases amyloid deposits and attenuates cognitive function deficits.FUS-mediated BBB opening increases adult hippocampal neurogenesis as well as drug delivery.We present an AD treatment strategy through the synergistic effect of the combined therapy of FUS and Adu. | Chanho Kong Eun-Jeong Yang Jaewoo Shin Junwon Park Si-Hyun Kim Seong-Wook Park Won Seok Chang Chang-Han Lee Hyunju Kim Hye-Sun Kim Jin Woo Chang | 2022 | Translational Neurodegeneration2022，11，1： | 0 |
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