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Acta Metallurgica sinica(English Letters) 2004年第5期17卷 632-638页

作者： K.J.Kim H.U.Hong K.s.Min s.w.nam Dept. of Materials science and Engineering Korea Advanced Institute of Science and Technology 373-1 Guseong-dong Yuseong-gu Deajeon 305-701 KoreaPosco Technical Research Laboratory #1 Koedong-dong Nam-gu Pohang 790-300 KoreaProcess Solution Development Team 1 LCD R&D Center AMLCD Division Device Solution Network Samsung Electronics Co. LTD.San 24 Nongseo-ri Giheung-eup Yongin Gyeonggi-do 449-771 KoreaDept. of Materials Science and Engineering Korea Advanced Institute of Science and Technology 373-1 Guseong-dong Yuseong-gu Deajeon 305-701 Korea

Modification of the carbide characteristics through the grain boundary serration is investigated, using an AIsI 316 and 304 stainless steels. In both steels, triangular carbides were observed at straight grain boundaries while planar carbides were observed at the serrated grain boundaries. The serrated grain boundary energy is observed to be much lower than that of the straight one. Therefore, the carbide morphology is found to be changed from triangular to planar along the serrated boundary to reduce the interfacial energy between the carbide and the matrix. The creep-fatigue properties of these steels at 873K have been investigated. The creep-fatigue life of the sample with planar carbide at the serrated grain boundary was found to be much longer than that with triangular carbide at the straight one. These results imply that the planar carbides with lower interfacial energy have higher cavitation resistance, resulting in the retardation of cavity nucleation and growth to increase creep-fatigue life.

关键词： cavity nucleation factor grain boundary serration carbide morphology austenitic stainless steel grain boundary cavitation

AssEssMENT OF DAMAGE AND LIFE PREDICTION OF AUsTENITIC sTAINLEss sTEEL UNDERHIGH TEMPERATURE FATIGUE CREEP INTERACTION CONDITION

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Acta Metallurgica sinica(English Letters) 1999年第4期12卷 304-314页

作者： s.w.nam Dept.of Materials science and Engineering , Korea Adv .Inst.of sci.and Tech .373 1 Gusong dong, Yusong gu ,Taejon 305 701 ,korea Korea Advanced Inst of science and Technology Taejon South Korea

Itis understood that grain boundary cavitation is one of the detrimental processes for thedegradation of materials that reduces the creep fatigue life at high temperatures. Anewdamagefunction based on a modelforthecreep fatiguelife prediction in termsof nucleationand growth ofgrain boundarycavitiesisproposed. Thisdamagefunctionisacombination ofthetermsrelated to the cavitational damagein thelife prediction equation and is generallyapplicabletothe materialsin which failureis controlled by the grain boundary cavitationaldamage. Thecreep fatiguedatafrom thepresentandotherinvestigationsareusedtocheckthevalidityofthe proposed function, and itisshown thattheysatisfythereliability of damagefunction. Additionally, using this damage function, one may realize that allthe Coffin Manson plotsatthevariouslevelsoftensileholdtimeandtemperatureunderstrain controlled creep fatiguetestscan be normalizedto makethe mastercurve.

关键词： austeniticstainlesssteel,creep fatigue grainboundarycavitation ,damage function holdtime

The effect of Al addition to prevent Ni sintering in steam reforming of bio-ethanol

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The effect of Al addition to prevent Ni sintering in steam r...

Effect of Eu3+,Bi3+,and Li+ doping on luminescent property of GdNbO4

第九届全国氢能学术会议

作者： H.Devianto s.P.Yoon s.w.nam T.H.Lim H.I.Lee seoul National University Korea Institute of science and Technology

＜正＞Reforming of bio-ethanol provides a promising method for hydrogen production from renewable *** most well-known active metal for ethanol steam reforming is Ni. Unfortunately,Ni sintering,however,cannot be avoided at high temperature and high water content,as shown in steam reforming of bio-ethanol for high temperature fuel cell application,

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Journal of Rare Earths 2024年第1期42卷 66-75页

作者： s.w.wi Y.s.Lee Department of Physics and Integrative Institute of Basic sciences Soongsil University

we investigated the emission properties of Eu3+-doped GdNbO4-based oxide phosphors,aiming at improving the Eu3+emission by codoping of Bi3+and Li+.Eu3+singly doped,Eu3+and Bi3+doubly doped,and Eu3+,Bi3+,and Li+triply doped GdNbO4were prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu3+in the singly doped samples are significantly improved by the codoping of Bi3+,mainly due to the energy transfer from Bi3+to Eu3+.The additional codoping of Li+is found to increase the Eu3+emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu3+in GdNbO4does not change significantly with the codoping of Bi3+and Li+.Our results indicate that Li+doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO4phosphors.

关键词： Eu 3+ GdNbO 4 Codoping of Li + Photoluminescence sensitizer Rare earths

Omnidirectional color wavelength tuning of stretchable chiral liquid crystal elastomers

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Light(science & Applications) 2024年第6期13卷 1062-1074页

作者： seungmin nam wontae Jung Jun Hyuk shin su seok Choi Department of Electrical Engineering Pohang University of Science and Technology(POSTECH)PohangKorea

wavelength-tunable structural colors using stimuli-responsive materials,such as chiral liquid crystals(CLCs),have attracted increasing attention owing to their high functionality in various tunable photonic ***,on-demand omnidirectional wavelength control is highly desirable from the perspective of wavelength-tuning ***,despite numerous previous research efforts on tunable CLC structural colors,only mono-directional wavelength tuning toward shorter wavelengths has been employed in most studies to *** this study,we report the ideally desired omnidirectional wavelength control toward longer and shorter wavelengths with significantly improved tunability over a broadband wavelength *** using areal expanding and contractive strain control of dielectric elastomer actuators(DEAs)with chiral liquid crystal elastomers(CLCEs),simultaneous and omnidirectional structural color-tuning control was *** breakthrough in omnidirectional wavelength control enhances the achievable tuning freedom and versatility,making it applicable to a broad range of high-functional photonic applications.

关键词： tuning tunable directional

superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.T.Jeong s.w.Lee w.J.Kim Department of Materials science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)with a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,were examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy was achieved by employing high-ratio differential speed *** best superplasticity was achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),where tensile elongations of 550±600%were *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size was observed at temperatures above 573 ***,it was important to consider this effect when analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow at low strain rates was governed by lattice diffusion-controlled grain boundary sliding,while at high strain rates,lattice diffusion-controlled dislocation climb creep was the rate-controlling deformation *** was concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it was observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps were constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy superplasticity severe plastic deformation Grain size Grain growth

Effect of siO2 and CeO2 to Ni bulk catalyst in water gas shift reaction

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Effect of SiO2 and CeO2 to Ni bulk catalyst in water gas shi...

Environmentally adaptive reshaping of plant photomorphogenesis by karrikin and strigolactone signaling

第九届全国氢能学术会议

作者： s.H.Kim J.H.Chung Y.T.Kim s.P.Yoon s.w.nam T.H.Lim H.I.Lee seoul National University Korea Institute of science and Technology

Ni bulk catalyst had been studied as an alternative to substitute water gas shift catalyst in our previous *** surface properties of the Ni bulk catalyst have been studied by various characterization methods adding siO and CeO to *** promoted catalysts have been applied to the water gas shift(wGs) reaction which converts CO to *** and CeO

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Journal of Integrative Plant Biology 2024年第5期66卷 865-882页

作者： Young-Joon Park Bo Eun nam Chung-Mo Park Department of smart Farm science Kyung Hee UniversityYongin 17104Korea Departmentof Biological sciences Seoul National UniversitySeoul 08826Korea Department of Chemistry Seoul National UniversitySeoul 08826Korea

Coordinated morphogenic adaptation of growing plants is critical for their survival and propagation under fluctuating *** morphogenic responses to light and warm temperatures,termed photomorphogenesis and thermomorphogenesis,respectively,have been extensively studied in recent *** photomorphogenesis,plants actively reshape their growth and developmental patterns to cope with changes in light ***,photomorphogenesis is closely associated with diverse growth hormonal ***,accumulating evidence indicates that light-directed morphogenesis is profoundly affected by two recently identified phytochemicals,karrikins(KARs)and strigolactones(sLs).KARs and sLs are structurally related butenolides acting as signaling molecules during a variety of developmental steps,including seed *** receptors and signaling mediators have been identified,and associated working mechanisms have been explored using gene-deficient mutants in various plant *** particular interest is that the KAR and sL signaling pathways play important roles in environmental responses,among which their linkages with photomorphogenesis are most comprehensively studied during seedling *** this review,we focus on how the phytochemical and light signals converge on the optimization of morphogenic *** also discuss molecular mechanisms underlying the signaling crosstalks with an aim of developing potential ways to improve crop productivity under climate changes.

关键词： karrikins morphogenic adaptation photomorphogenesis seedling establishment strigolactones

Products of Commutator Ideals of some Lie-admissible Algebras

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Acta Mathematica sinica,English series 2024年第8期40卷 1875-1892页

作者： Ivan KAYGORODOV Farukh MAsHUROV Tran Giang nam Ze Rui ZHANG CMA-UBI Universidade da Beira InteriorCovilhaPortugal shenzhen International Center for Mathematics(sICM) Southern University of Science and TechnologyShenzhen 518055P.R.China Institute of Mathematics VAST18 Hoang Quoc VietCau GiayHanoiVietnam school of Mathematical sciences South China Normal UniversityGuangzhou 510631P.R.China

In this article,we mainly study the products of commutator ideals of Lie-admissible algebras such as Novikov algebras,bicommutative algebras,and assosymmetric *** precisely,we first study the properties of the lower central chains for Novikov algebras and bicommutative *** we show that for every Lie nilpotent Novikov algebra or Lie nilpotent bicommutative algebra A,the ideal of A generated by the set{ab−ba|a,b∈A}is ***,we study properties of the lower central chains for assosymmetric algebras,study the products of commutator ideals of assosymmetric algebras and show that the products of commutator ideals have a similar property as that for associative algebras.

关键词： Novikov algebra bicommutative algebra assosymmetric algebra Lie nilpotent algebra

Reconstruction of cervical necrotizing fasciitis defect with the modified keystone flap technique:Two case reports

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world Journal of Clinical Cases 2024年第7期12卷 1305-1312页

作者： wonseok Cho Eun A Jang Kyu nam Kim Department of Plastic and Reconstructive surgery Kangbuk Samsung HospitalSungkyunkwan University School of MedicineSeoul 03181South Korea

BACKGROUND Cervical necrotizing fasciitis(CNF)is a rare,aggressive form of deep neck space infection with significant morbidity and mortality *** surgical debridement acts as the cornerstone of CNF treatment;however,it often results in defects requiring complex *** sUMMARY we report two cases in which the keystone flap(KF)was used for CNF defect coverage:Case 1,an 85-year-old patient with CNF in the anterior neck,and Case 2,a 54-year-old patient with CNF in the posterior *** patients received empirical intravenous antibiotic therapy and underwent serial debridement,enabling adequate wound preparation and *** final defect size measured 5.5 cm×12 cm in Case 1 and 6 cm×11 cm in Case *** defect coverage,we employed an 8 cm×19 cm type II KF based on perforators from the superior thyroid artery in Case 1 and a 9 cm×18 cm type II KF based on perforators from the transverse cervical artery in Case *** flaps showed complete *** postoperative complications occurred in both cases,and favorable outcomes were observed at 7-and 6-month follow-ups in case 1 and 2,*** we effectively treated CNF-associated defects using the KF technique;KF is viable for covering CNF defects in carefully selected cases.

关键词： Fasciitis Necrotizing Debridement Plastic surgery Dermatologic surgical procedures Case report