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Acta Geologica Sinica(English Edition) 2009年第5期83卷 845-852页

作者： seung-ho jung Seong-Joo LEE Department of Geology Kyungpook National UniversityDaegu 702-701Korea

A total of 16 specimens of fossil-winged fruits were found from the Middle Miocene marine deposits, Duho Formation, Pohang Basin, Korea. They were identified into two structurally different groups： 15 specimens into a winged fruit of Fraxinus, and one specimen of Liriodendron. The most samaras （13 specimens） were identified as Fraxinus oishii, which is characterized by narrowly ovate or ovate-elliptic shapes that are 2.7-3.6 cm in length and 0.7-1 cm in width （i/w ratio=3.4-4）. The apexes of the Fraxinus oishii samara are round or slightly emarginated, and a seed of the samara is always located at the base, of which the general shape is narrow rhombic-ellipsoidal. The seed is 1.2-2 cm long and 0.5-0.7 cm wide. Two specimens are different from the samara of Fraxinus oishii. They have a 6.6 length/width ratio （3.3 cm long and 0.5 cm wide）, and thus, are temporarily classified into the Fraxinus sp. One specimen was recognized as a winged seed of Liriodendron meisenense. The wing is broadly lanceolate to elliptic in shape, has a smooth, acute apex, and is approximately 3 cm long and 0.7 cm wide. Samaras of Fraxinus oishii and Liriodendron meisenense were early reported from the Middle Miocene deposits from North Korea, but these specimens are the first discovery in South Korea. Further study of the Duho Formation may connect flora relationships between North and South Korea.

关键词： winged fruits Fraxinus Liriodendron Middle Miocene Pohang Basin Korea

Fossil Winged Fruits of Fraxinus and Liriodendron from the Duho Formation,Pohang Basin,Korea

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地学前缘 2009年第S1期16卷 251-251页

作者： seung-ho jung Seong-Joo Lee Department of Geology Kyungpook National University

The Middle Miocene Duho Formation of the Yeonil Group,Pohang Basin,Korea is one of the best recognized formations for the Cenozoic plant fossils, including various leaves,reproductive organs,and fossil ***,in this paper,first report winged fruits(10 specimens) from the Duho *** were identified into two structurally different groups:

关键词： fossil fruit Fraxinus Liriodendron reproductive organ

Depth perception on fundus images using a single-channel stereomicroscopy

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Journal of Innovative Optical Health Sciences 2021年第3期4卷 68-76页

作者： Edalat Radfar Hyunseon Yu Tien Son ho seung ho Choi Byungjo jung Department of Biomedical Engineering Yonsei University Wonju-siGangwon-do 26493 Republic of Korea Research Center for Science and Technology in Medicine Tehran University of Medical Sciences Tehran 14185-615Iran Institute of Metabolism and Systems Research University of Birmingham Edgbaston Birmingham B152TTUK

Typical fundus photography produces a two-dimensional *** makes it difficult to observe the microvascular and neural abnormalities,because the depth of the image is *** provide depth appreciation,we develop a single-channel stereoscopic fundus video imaging sys-tem based on a rotating *** respect to the pupil center,the rotating refractor laterally displaces the optical path and the *** allows standard monocular fundus cameras to generate stereo-parallax and image disparity through sequential image *** opti-mize our imaging system,characterize the stereo-base,and image an eyeball model and a rabbit *** virtual realities are considered,our imaging system can be a simple yet efficient technique to provide depth perception in a virtual space that allows users to perceive abnor-malities in the eye fundus.

关键词： Imaging systems ophthalmic optics and devices refraction vision-binocular and stereopsis

Fabrication and characterization of Ag flake hybrid circuits with IPL-sintering

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Journal of Materials Science & Technology 2020年第18期52卷 13-18页

作者： Choong-Jae Lee Kwang-ho jung Kyung Deuk Min Bum-Geun Park seung-Boo jung School of Advanced Materials Science Engineering Sungkyunkwan University2066 Seobu-roJangan-guSuwon-si16419Republic of Korea Visual Display Business Samsung Electronics Co.Ltd.129Samsung-roYeongtong-guSuwon-si16677Republic of Korea

The study of photonic sintering has gained interest based on the advantages of fast processing at room ***,printed electronics made from photonic sintering with an intensive pulsed light(IPL)energy source exhibit more mechanical instability than those made from conventional thermal sintering *** solve the mechanical instability problems,we fabricated Ag flake hybrid pastes with a variety of concentrations of Ag flake(0,25,50,75,and 100 wt.%).All of the screen-printed hybrid Ag circuits were fabricated on polyimide substrates and were sintered at 3.5 *** porosity was analyzed using the Brunauer-Emmett-Teller *** IPC(Packaging Electronic Circuits)sliding test was performed to analyze the flexibility of the screen-printed Ag flake hybrid *** adhesion strength of the hybrid circuits was evaluated with a roll-type 90°peel *** hybrid Ag printed circuit showed improvements in both the flexibility and adhesion strength with the addition of Ag flake.

关键词： Low-temperature sintering Flexibility Flaky powders Adhesion strength Intensive pulsed light

Three-dimensional porous graphene-metal oxide composite microspheres： Preparation and application in Li-ion batteries

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Nano Research 2015年第5期8卷 1584-1594页

作者： seung ho Choi jung-Kul Lee Yun Chan Kang Department of Materials Science and Engineering Korea University Anam-Dong Seongbuk-Gu Seou1136-713 Republic of Korea Department of Chemical Engineering Konkuk University 1 Hwayang-Dong Gwangjin-Gu Seou1143-701 Republic of Korea

The use of new three-dimensional （3D） porous graphene-metal oxide composite microspheres as an anode material for Li-ion batteries （LIBs） is first introduced here. 3D graphene microspheres are aggregates of individual hollow graphene nanospheres composed of graphene sheets. Metal oxide nanocrystals are uniformly distributed over the graphene surface of the microspheres. The 3D porous graphene-SnO2 microspheres are selected as the first target material for investigation because of their superior electrochemical properties. The 3D porous graphene-SnO2 and graphene microspheres and bare SnO2 powders deliver discharge capacities of 1,009, 196, and 52 mAh·g^-1, respectively, after 500 cycles at a current density of 2 A·g^-1 .The 3D porous graphene-SnO2 microspheres exhibit uniquely low charge transfer resistances and high Li-ion diffusivities before and after cycling.

关键词： graphene metal oxide nanostructures electrode material batteries

Impact loads generated by tandem cavitation bubble on solid wall

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Journal of Hydrodynamics 2022年第3期34卷 467-482页

作者： Nyo Me Thet Naing Jaehyun Park seung-ho Hyun Rho-Taek jung School of Naval Architecture and Ocean Engineering University of UlsanUlsanKorea School of Electrical Engineering University of UlsanUlsanKorea Foundation for Industry Cooperation University of UlsanUlsanKorea

Experiments on two cavitation bubbles,which are generated at the same instant,with three different sizes near solid wall are conducted and their impulses on the boundary are registered by polyvinylidene fluoride(PVDF)*** to being near the boundary,bubble interactions and deformed features are in contrast with those in infinite fluid *** this paper,five morphologies of bubble deformation during growth and collapse phases are observed by high-speed *** profiles are strongly influenced by inter-bubble distance(η),stand-off distance from boundary(γ),and bubble size *** of photographs coupled with sensor measurements enabled qualitative investigation of two bubble interactions on the *** sensor data acquisition,it is confirmed that lower bigger bubble with upper smaller bubble configuration produces highest impulses on the boundary compared with other vertical arrangements of the tandem cavitation bubble employed in this study.

关键词： Two bubbles spark-generated bubble impulse polyvinylidene fluoride(PVDF)

Influence of sulfides on the tribological properties of composites produced by pulse electric current sintering

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International Journal of Minerals,Metallurgy and Materials 2014年第1期21卷 95-103页

作者： seung ho Kim Department of Electronics Engineering Dankook University

Self-lubricating A1203-15wt% ZrO2 composites with sulfides, such as molybdenum disulfide （MoS2） and tungsten disulfide （WSz） serving as solid lubricants, were fabricated by using the pulse electric current sintering （PECS） technique. The coefficient of friction （COF） of the A1203-15wt% ZrO2 composite without/with sulfides was in the range of 0.37-0.48 and 0.27-0.49, respectively. As the amoant of sul- fides increased, the COF and the wear rate decreased. The reduction in COF and wear rate of the sulfide-containing composite is caused by a reduction in shear stresses between the specimen and the tribological medium due to the formation of a lubricating film resulting from the lamellar structure of sulfides located on the worn surface.

关键词： ceramic composites coefficient of friction solid lubricants sulfides wear of materials

Behavior of CaO and Calcium in pure Magnesium

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Rare Metals 2006年第z2期25卷 150-154页

作者： HA Seong-ho LEE Jin-Kyu JO Hyung-ho jung seung-Boo KIM Shae K. Department of Advanced Material Engineering Sungkyunkwan University 300 Chunchun-dong Jangan-gu Suwon Gyunggi-do 440-746 KoreaAdvanced Material Division Korea Institute of Industrial Technology 7-47 Songdo-dong Yeonsu-gu Incheon 406-840 Korea Advanced Material Division Korea Institute of Industrial Technology 7-47 Songdo-dong Yeonsu-gu Incheon 406-840 Korea Department of Advanced Material Engineering Sungkyunkwan University 300 Chunchun-dong Jangan-gu Suwon Gyunggi-do 440-746 Korea

Mg alloys exhibit a number of good properties such as low density, good castability and high specific strength. however, molten Mg and Mg alloys are ignited without the melt protective gases during melting and casting process due to their high reactivity. The purpose of this study is to investigate effects of Ca and CaO on pure Mg through microstructure observation, ignition test and phase analysis. With increasing Ca and CaO contents, the ignition resistance of Ca or CaO added pure Mg is increased and the grains are refined. As results of XRD and EDS, CaO is reduced to Ca in CaO added pure Mg. Mg2Ca phase is formed even in 0.1 wt.%CaO added pure Mg by reduction mechanism, while Mg2Ca phase is formed over 1.35 wt.% Ca added pure Mg.

关键词： Mg CaO ignition resistance Mg2Ca phase

Effect of TiO_2 on the viscosity and structure of low-fluoride slag used for electroslag remelting of Ti-containing steels

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International Journal of Minerals,Metallurgy and Materials 2017年第1期24卷 18-24页

作者： Cheng-bin Shi Ding-li Zheng seung-ho Shin Jing Li jung-wook Cho State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Graduate Institute of Ferrous Technology Pohang University of Science and Technology

The viscosity of CaF_2-CaO-Al_2O_3-MgO-（TiO_2） slag was measured using a rotating crucible viscometer. Raman spectroscopy analysis was performed to correlate the viscosity to slag structure. The viscosity of the slag was found to decrease with increasing TiO_2 content in the slag from 0 to 9.73wt%. The activation energy decreased from 95.16 kJ /mol to 79.40 kJ /mol with increasing TiO_2 content in the slag. The introduction of TiO_2 into the slag played a destructive role in Al-O-Al structural units and Q^4 units by forming simpler structural units of Q^2 and Ti_2O_6^（4-） chain. The amount of Al-O-Al significantly decreased with increasing TiO_2 content. The relative fraction of Q^4 units in the [AlO_4]^（5-）-tetrahedral units shows a decreasing trend, whereas the relative fraction of Q^2 units and Ti_2O_6^（4-） chain increases with increasing TiO_2 content accordingly. Consequently, the polymerization degree of the slag decreases with increasing TiO_2 content. The variation in slag structure is consistent with the change in measured viscosity.

关键词： electroslag remelting slag titanium dioxide viscosity structure

Dual-frequency piezoelectric micromachined ultrasound transducer based on polarization switching in ferroelectric thin films

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Microsystems & Nanoengineering 2023年第5期9卷 233-243页

作者： Jin Soo Park Soo Young jung Dong Hun Kim jung ho Park ho Won Jang Tae Geun Kim seung-Hyub Baek Byung Chul Lee Bionics Research Center Korea Institute of Science and TechnologySeoul 02792Republic of Korea Department of Electrical Engineering Korea UniversitySeoul 02841Republic of Korea Center for Electronic Materials Korea Institute of Science and TechnologySeoul 02792Republic of Korea Department of Material Science and Engineering Seoul National UniversitySeoul 08826Republic of Korea Division of Bio-Medical Science and Technology KIST SchoolUniversity of Science and Technology(UST)Seoul 02792Republic of Korea KHU-KIST Department of Converging Science and Technology Kyung Hee UniversitySeoul 02447Republic of Korea

Due to its additional frequency response,dual-frequency ultrasound has advantages over conventional ultrasound,which operates at a specific frequency ***,a tunable frequency from a single transducer enables sonographers to achieve ultrasound images with a large detection area and high *** facilitates the availability of more advanced techniques that simultaneously require low-and high-frequency ultrasounds,such as harmonic imaging and image-guided *** this study,we present a novel method for dual-frequency ultrasound generation from a ferroelectric piezoelectric micromachined ultrasound transducer(PMUT).Uniformly designed transducer arrays can be used for both deep low-resolution imaging and shallow high-resolution *** switch the ultrasound frequency,the only requirement is to tune a DC bias to control the polarization state of the ferroelectric *** vibration of the PMUT membrane strongly depends on the polarization state,producing low-and high-frequency ultrasounds from a single excitation *** strategy for dual-frequency ultrasounds meets the requirement for either multielectrode configurations or heterodesigned elements,which are integrated into an ***,this technique significantly reduces the design complexity of transducer arrays and their associated driving circuits.

关键词： piezoelectric ferroelectric enable