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Analytical evaluation and experimental validation on dynamic rocking behavior for shallow foundation considering structural response

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Earthquake Engineering and Engineering Vibration 2022年第1期21卷 37-51页

作者： Kil-Wan ko Jeong-Gon Ha Dong-Soo Kim Department of Civil and Environmental Engineering UC BerkeleyCalifornia 94720USA Advanced Structures and Seismic Safety Research Division Daejeon 34057Korea Department of Civil and Environmental Engineering KAISTDaejeon 34141Korea

The challenge in the practical application of rocking foundations is the estimation of its performance,particularly the rotation angle,during a strong *** this study,the dynamic rocking behavior for a shallow foundation considering structural response was evaluated through two analytical approaches:the conventional soil-foundation-structure interaction(SFSI)governing equation of a single-degree-of-freedom(SDOF)structure on a rocking shallow foundation,and the Housner rocking model(i.e.,a rocking rigid block on a rigid base).Both approaches were validated with dynamic centrifuge *** test models consisted of a soft soil deposit,a shallow rectangular foundation,and an SDOF structure dominated by a bending behavior.A total of 11 foundation-structure systems and six seismic waves,including recorded earthquake signals and sinusoidal waves,were *** results showed that the conventional SFSI equation well predicted the maximum rotation during strong ***,this method was less accurate regarding the rotational phase information and maximum rotation of the foundation during weak *** the other hand,although the modified Housner′s rocking model required five parameters relevant to a soil-foundation-structure system,it overestimated the maximum rotation of the foundation when compared with the results from dynamic centrifuge tests.

关键词： soil-foundation-structure interaction maximum rotation angle rocking foundation Housner rocking model dynamic centrifuge test

Density functional theory study on the role of ternary alloying elements in TiFe-based hydrogen storage alloys

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Journal of Materials Science & Technology 2021年第33期92卷 148-158页

作者： Won-Seok ko Ki Beom Park Hyung-Ki Park School of Materials Science and Engineering University of UlsanUlsan 44610Republic of Korea Functional Materials and Components R&D Group Korea Institute of Industrial TechnologyGangneung 25440Republic of Korea

The role of additional ternary alloying elements on the performance of stationary TiFe-based hydrogen storage alloys was investigated based on first-principles density functional theory *** a basic step for examinations,the site preference of each alloying element in the stoichiometric and nonstoichiometric B2TiFe compounds was clarified considering possible antisite *** on the revealed site preference,the effect of various possible ternary elements on the hydrogen storage was examined by focusing on the formation enthalpies of TiFeH and TiFeH_(2) hydrides,which were closely related to the change in the location of plateaus in the pressure-composition-temperature *** physical properties such as the volume expansion due to hydride formation were also examined to provide additional criteria for selecting optimum alloying conditions in future alloying design *** alloying elements that maximize the grain boundary embrittlement due to the solute segregation were proposed for the enhanced initial activation of TiFe-based hydrogen storage alloys.

关键词： Hydrogen storage alloy Titanium-iron Density functional theory calculation Metallic hydride

Effect of FeO concentration in sinter iron ore on reduction behavior in a hydrogen-enriched blast furnace

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International Journal of Minerals,Metallurgy and Materials 2022年第10期29卷 1820-1829页

作者： ko-ichiro Ohno Takayuki Maeda Kazuya Kunitomo Masashi Hara Department of Materials Faculty of EngineeringKyushu University744 MotookaNishi-kuFukuoka 819-0395Japan Kashima Area East Nippon WorksNippon Steel Corporation3 HikariKashima CityIbaraki 314-0014Japan

Japan started the national project“COURSE 50”for CO_(2) reduction in the *** project aimed to establish novel technologies to reduce CO_(2) emissions with partially utilization of hydrogen in blast furnace-based ironmaking by 30%by around 2030 and use it for practical applications by *** idea is that instead of coke,hydrogen is used as the reducing agent,leading to lower fossil fuel consumption in the *** has been reported that the reduction behavior of hematite,magnetite,calcium ferrite,and slag in the sinter is different,and it is also considerably influenced by the sinter *** study aimed to investigate the reduction behavior of sinters in hydrogen enriched blast furnace with different mineral morphologies in CO-CO_(2)-H2 mixed *** an experimental sample,two sinter samples with significantly different hematite and magnetite ratios were prepared to compare their reduction *** reduction of wustite to iron was carried out at 1000,900,and 800℃ in a CO-CO_(2)-H2 atmosphere for the mineral morphology-controlled sinter,and the following findings were *** reduction rate of smaller amount of FeO led to faster increase of the reduction rate curve at the initial stage of ***-observations of reduced samples showed that the reaction proceeded from the outer periphery of the sample toward the inside,and a reaction interface was observed where reduced iron and wustite ***-observations revealed three layers,namely,wustite single phase in the center zone of the sample,iron single phase in the outer periphery zone of the sample,and iron oxide-derived wustite FeO and iron,or calcium ferritederived wustite'FeO'and iron in the reaction interface zone.A two-interface unreacted core model was successfully applied for the kinetic analysis of the reduction reaction,and obtained temperature dependent expressions of the chemical reaction coefficients from each mineral phases.

关键词： hydrogen reduction wustite hematite magnetite calcium ferrite two-interface unreacted core model COURSE50

Significant control of metal-insulator transition temperature through catalytic excessive oxygen doping in high-performance vanadium dioxide nanobeam channel

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Journal of Materials Science & Technology 2020年第9期44卷 96-101页

作者： Minhwan ko Sang Yeon Lee Jucheol Park Hyungtak Seo Department of Energy Systems Research Ajou UniversitySuwon16499Republic of Korea Gyeongbuk Science Technology Promotion Center Gumi Electronics&Information Technology Research InstituteGumi39717Republic of Korea Department of Materials Science and Engineering Ajou UniversitySuwon16499Republic of Korea

The strategy of a reliable transition temperature control of vanadium dioxide(VO2)is *** VO2 nanobeams were synthesized by a thermal chemical vapor deposition(TCVD)*** metal-insulator transition(MIT)temperature increases to above 380K when the TiO2 ratio of the source is 5 at.%,although the Ti source is not physically doped into VO2 *** XPS spectra of the V 2p orbital reveal the excessive oxidation of V after the TCVD processes with a higher TiO2 ratio,indicating that the TiO2 precursor is important in the O-doping of the surface V O bonds when forming volatile Ti-O gas ***,TiO2 reactants can be used as a VO2 surface chemical modifier to manipulate the MIT transition temperature and maintain a homogenous VO2 phase,which is useful for a Mott device application with a record on/off switching ratio>104 and Mott transition temperature>380 K.

关键词： VO2 Mott transition Metal-insulator transition temperature Oxygen doping Titanium catalyst

Modifying current thin-film microextraction(TFME)solutions for analyzing prohibited substances:Evaluating new coatings using liquid chromatography

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Journal of Pharmaceutical Analysis 2022年第3期12卷 470-480页

作者： Łukasz Sobczak Dominika kołodziej Krzysztof Gorynski Bioanalysis Scientific Group Faculty of PharmacyCollegium Medicum in Bydgoszcz at Nicolaus Copernicus University in Torun85-089BydgoszczPoland

For identifying and quantifying prohibited substances,solid-phase microextraction(SPME)continues to arouse interest as a sample preparation ***,the practical implementation of this method in routine laboratory testing is currently hindered by the limited number of coatings compatible with the ubiquitous high-performance liquid chromatography(HPLC)*** octadecyl(C18)and polydimethylsiloxane/divinylbenzene ligands are currently marketed for this *** address this situation,the present study evaluated 12 HPLC-compatible coatings,including several chemistries not currently used in this *** stationary phases of SPME devices in the geometry of thin filmcoated blades were prepared by applying silica particles bonded with various functional ligands(C18,octyl,phenyl-hexyl,3-cyanopropyl,benzenesulfonic acid,and selected combinations of these),as well as unbonded silica,to a metal *** of these chemistries have not been previously used as microextraction *** 48 most commonly misused substances were selected to assess the extraction efficacy of each coating,and eight desorption solvent compositions were used to optimize the desorption *** samples were analyzed using an HPLC system coupled with triple quadrupole tandem mass *** evaluation enables selection of the best-performing coatings for quantifying prohibited substances and investigates the relationship between extraction efficacy and the physicochemical characteristics of the ***,using the most suitable coatings is essential for trace-level analysis of chemically diverse prohibited substances.

关键词： Sample preparation Solid-phase microextraction Thin-film microextraction Prohibited substances Drugs of abuse High-performance liquid chromatography

Stick-and-play system based on interfacial adhesion control enhanced by micro/nanostructures

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Nano Research 2021年第9期14卷 3143-3158页

作者： Jung II Yoo Seung Hyun Kim Heung Cho ko School of Materials Science and Engineering Gwangju Institute of Science and Technology(GIST)Gwangju 61005Republic of Korea

The evolution of membrane-type electronics has facilitated the development of stick-and-play systems,which confer diverse electrical functions to various planar or arbitrary curvilinear *** stick-and-play concept is based on the development of thin electronic devices in a printable format and their subsequent transfer to target *** development of this technology requires control of the interfacial adhesion of the electronic prints for retrieval from a carrier and transfer to the target ***,we discuss the transfer printing for membrane-type electronics,starting from an overview of materials available for flexible substrates,transfer printing of electronic prints for retrieval,and assembly for further ***,we explain the stick-and-play concept based on fabricated membrane-type electronics;"stick" and “play"refer to the transfer of electronic devices and the performance of their electronic functions,*** particular,we broadly survey various methods based on micro/nanostructures,including gecko-inspired,interlocking,cephalopod-sucker-inspired,and cilia structures,which can be employed to stick-and-play systems for enhancing interfacial adhesion with complex target surfaces under dynamic and wet ***,we highlight the stick-and-play system application of micro/nanostructures for skin-attachable biomedical electronics,e-textiles,and environmental monitoring electronics.

关键词： transfer printing interfacial adhesion flexible electronics stick-and-play system bioinspired adhesive

Deep-water cirripedes colonizing dead shells of the cephalopod Nautilus macromphalus from New Caledonian waters

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Integrative Zoology 2019年第6期14卷 561-575页

作者： John BUCKERIDGE TomáškoČÍ Ján SCHLÖGL Adam TOMAŠOVÝCH Martina koČOVÁVESELSKÁ Earth&Oceanic Systems Group RMIT UniversityMelbourneVictoriaAustralia Ivančická581 PragueCzech Republic and Palaeontological DepartmentNatural History MuseumNational MuseumPragueCzech Republic Department of Geology and Paleontology Comenius University in BratislavaBratislavaSlovakia Institute of Earth Sciences Slovak Academy of SciencesBratislavaSlovakia Department of Paleobiology and Paleoecology Institute of Geology of the Czech Academy of SciencesPragueCzech Republic Museums Victoria MelbourneVictoriaAustralia Faculty of Science Charles University in PraguePragueCzech Republic

Fossil cephalopods are frequently encrusted by epibionts;however,determining whether encrustation occurred prior to or post-mortem to the host,and whether the final environment of deposition corresponds to the habitat of encrustation is *** present paper describes cirripede epibionts,their calcareous bases and their attachment scars on 6 post-mortem shells of Nautilus macromphalus,collected from deep water off New Cale*** cirripedes have left both cemented calcareous bases of Hexelasma and scars associated with bioerosion and discoloration produced by verrucomorph *** cirripedes included a Metaverruca recta,with articulated opercular plates and organic tissue(on a shell that had been exposed on the sea floor for at least 150 years),and specimens of Hexelasma velutinum,one of which was partly attached to an internal surface of a *** disposition of verrucomorphs indicates that most Nautilus shells were colonized post-mortem rather than during a floating ***,as cirripedes are known to have colonized living Nautilus,some Hexelasma,preserved only as calcareous eroded bases,may represent specimens that settled on a living *** degree of bioerosion and discoloration induced by verrucomorph barnacles varies according to the surface preservation of Nautilus shells,with deeper and discolored traces preserved on old and degraded *** made by verrucomorphs described here are ellipsoidal and a new ichnotaxon,Anellusichnus ellipticus,is proposed to accommodate ***,verrucomorphs and other cirripede taxa with membranous bases that were attached to pristine shells may not leave any substantial scars,and,thus,will be difficult to detect in the fossil record.

关键词： Anellusichnus ellipticus isp.nov cirripedes epibionts Hexelasma velutinum Metaverruca recta

COMMON FIXED POINT THEOREMS FOR MULTI-VALUED MAPS

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Acta Mathematica Scientia 2012年第2期32卷 818-824页

作者： Boško Damjanovic Bessem Samet Calogero Vetro Department of Mathematics Faculty of AgricultureNemanjina 6BelgradeSerbia universitéde Tunis Département de MathématiquesEcole Supérieure des Sciences et Techniques de Tunis Department of Mathematics and Informatics University of PalermoVia Archirafi3490123 PalermoItaly

We establish some results on coincidence and common fixed points for a twopair of multi-valued and single-valued maps in complete metric spaces. Presented theorems generalize recent results of Gordji et al [4] and sev... 详细信息

关键词： Coincidence point common fixed point multi-valued maps

Effective Elastic Properties of 3-Phase Particle Reinforced Composites with Randomly Dispersed Elastic Spherical Particles of Different Sizes Dedicated to Professor Karl Stark Pister for his 95th birthday

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Computer Modeling in Engineering & Sciences 2021年第12期129卷 1305-1328页

作者： Yu-Fu ko Jiann-Wen Woody Ju Civil Engineering and Construction Engineering Management California State UniversityLong BeachCA 90840-5101USA Civil and Environmental Engineering University of CaliforniaLos AngelesCA 90095-1593USA

Higher-order multiscale structures are proposed to predict the effective elastic properties of 3-phase particle reinforced composites by considering the probabilistic spherical particles spatial distribution,the particle interactions,and utilizing homogenization with ensemble volume average *** matrix material,spherical particles with radius a1,and spherical particles with radius a2,are denoted as the 0th phase,the 1st phase,and the 2nd phase,***,the two inhomogeneity phases are different particle sizes and the same elastic material *** higher-order(in ratio of spherical particle sizes to the distance between the centers of spherical particles)bounds on effective elastic properties of 3-phase particle reinforced proposed Formulation II and Formulation I derive *** a special case,i.e.,particle size of the 1st phase is the same as that of the 2nd phase,the proposed formulations reduce to 2-phase *** theoretical predictions demonstrate excellent agreement with selected experimental *** addition,several numerical examples are presented to demonstrate the competence of the proposed frameworks.

关键词： Particle reinforced composites micromechanics spherical particle interactions ensemble volume average homogenization probabilistic spatial distribution higher-order bounds multiscale