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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

Synergetic analysis of springtime air pollution episodes over Gwangju,Korea

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Journal of Environmental Sciences 2017年第7期29卷 270-283页

作者： Sung-Kyun shin Kwon-ho Lee seung-Shik Park Man Sing Wong Research Institute for Radiation-Satellite(RIRS) Gangneung-Wonju National University(GWNU)Gangneung 25457Republic of Korea Department of Atmospheric and Environmental Sciences(DAES) Gangneung-Wonju National University(GWNU)Gangneung 25457Republic of Korea Department of Environment and Energy Engineering Chonnam National UniversityGwangju 61186Republic of Korea Department of Land Surveying and Geo-Informatics The Hong Kong Polytech UniversityKowloonHong Kong

The characteristics of springtime aerosols,including their optical and microphysical properties,were analyzed for the months of March to May of 2009 in Gwangju（35.23°N,126.84°E）,Korea.A high Light Detection and Ranging（LIDAR）-derived aerosol depolarization ratio（δ） of 0.25 ± 0.04 was determined on dust particles during the observation ***？ngstr？m exponent values of the 440–870 nm wavelength pair（？_（440–870）） and single-scattering albedo at 675 nm（Ω_（675）） measured by a CIMEL sun/sky radiometer were 0.77 ± 0.19 and 0.95 ±0.01,*** elevated dust layers reached a maximum elevation of 4 km above sea ***/smoke particles that originated from highly populated/industrialized regions could be distinguished by their relatively smaller particle size（？_（440–870） ranged between1.33 and 1.36） and higher light-absorbing（Ω_（675） of 0.92 ± 0.01） *** aerosols are mostly distributed at altitudes 〈 1.2 *** root-mean-square deviation（RMSD） between the aerosol optical depth（AOD,τ） derived from LIDAR_（（τ_（LIDAR））） and from the CIMEL sun/sky radiometer_（（τ_（CIMEL））） varied with respect to the surface PM10 *** RMSD between τ_（LIDAR） and τ_（CIMEL） was as low as 13% under lower PM_（10） concentration levels（〈 100 μg/m^3）.In contrast,the RMSD between τ_（LIDAR） and τ_（CIMEL） increased three times（~31%） under high surface PM_（10） concentration levels（〉100 μg/m^3）.These results suggest that the accuracy of τ_（LIDAR） is influenced by specific atmospheric conditions,regardless of its uncertainty.

关键词： LIDAR Sun/sky radiometer MODIS Optical/microphysical properties Aerosol optical depth

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

Specific oceanographic characteristics and phytoplankton responses influencing the primary production around the Ulleung Basin area in spring

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Acta Oceanologica Sinica 2020年第2期39卷 107-122页

作者： Minji Lee Jin ho Kim Yun-Bae Kim Chan hong Park Kyoungsoon shin seung ho Baek South Sea Research Institute Korea Institute of Ocean Science and TechnologyGeoje 53201Korea Ulleungdo/Dokdo Ocean Science Station Korea Institute of Ocean Science and TechnologyUlleungdo 40205Korea Dokdo Research Center East Sea Research InstituteKorea Institute of Ocean Science and TechnologyUljin 36315Korea

The East Sea(Sea of Japan)is a marginal,semi-closed sea in the northwestern *** Ulleung Basin area,which is located near the subpolar front of the East Sea,is known to have high primary production and good fisheries in spring *** episodic wind-driven events during the spring of 2017,horizontal and vertical profiles of physical chemical biological factors were investigated at 29 stations located in the Ulleung Basin *** addition,growth responses of phytoplankton communities to nutrient additions were evaluated by bioassay experiments to understand the fluctuation of phytoplankton *** of strong northwestern wind,phytoplankton biomass was scattered and upwelling phenomenon might be suppressed in this *** phytoplankton abundances in the coastal stations were significantly higher than offshore and island *** contrast,the nutrient and chlorophyll a(Chl a)concentrations and the phytoplankton biomass were quite low in all *** was dominated group(>75.1%for coastal,40.0%for offshore and 43.6%for island stations).In the algal bioassays,the phytoplankton production was stimulated by N *** in vivo Chl a values in the+N and+NP treatments were significantly higher than the values in the control and the+P *** on the field survey,the higher nutrients in coastal waters affected the growth of diatom assemblages,however,little prosperity of phytoplankton was observed in the offshore waters despite the injection of sufficient nutrients in bioassay *** growth of phytoplankton depended on the initial cell *** of results indicated that a dominant northwestern wind led to a limited nutrients condition at euphotic layers,and the low level of biomass supply from the coasts resulted in low primary *** supplying nutrients and introducing phytoplankton through the currents are critical to maintain the high productivity in the Ulleung Basin area of the East Sea.

关键词： Ulleung Basin Ulleungdo and Dokdo spring phytoplankton blooms episodic windstorm algal bioassays primary production

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Journal of Central South University 2013年第4期20卷 982-987页

作者： LEE Myeong-ho 魏荷 LEE Sang-hyuk LEE Sang-min shin seung-soo Department of e-Commerce Semyung University Department of Electrical and Electronic Engineering Xi'an Jiaotong-Liverpool University Institute for Information and Electronics Research Inha University Department of Information Security Tongmyung University

Similarity measure design for discrete data group was proposed. Similarity measure design for continuous membership function was also carried out. Proposed similarity measures were designed based on fuzzy number and distance measure, and were proved. To calculate the degree of similarity of discrete data, relative degree between data and total distribution was obtained. Discrete data similarity measure was completed with combination of mentioned relative degrees. Power interconnected system with multi characteristics was considered to apply discrete similarity measure. Naturally, similarity measure was extended to multi-dimensional similarity measure case, and applied to bus clustering problem.

关键词： similarity measure multi-dimension discrete data relative degree power interconnected system

Distribution of dinoflagellate cysts in Yellow Sea sediments

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Acta Oceanologica Sinica 2013年第9期32卷 91-98页

作者： shin Hyeon ho LIM Dhongil PARK Soung-Yun HEO seung KIM So-Young Library of Marine Samples Korea Institute of Ocean Science and Technology West Sea Fisheries Research Institute National Fisheries Research&Development Institute Division of Polar Climate Research Korea Polar Research Institute

To investigate the distribution, abundance, and species composition of dinoflagellate cysts in the Yellow Sea, surface sediment samples were collected at 37 sites, including the Korean dump site. Twenty-one di- noflagellate cyst taxa were identified, with the assemblages dominated mainly by Spiniferites bulloideus, Operculodinium centrocarpum, and cyst of Alexandrium catenella/tarnarense type. A high frequency of O. centrocarpum in the Yellow Sea was observed for the first time, and it is likely that this can be attributed to the dynamics of the Yellow Sea Cold Water Mass and the Changjiang （Yangtze） River runoff. Total cyst concentrations ranged from 23 to 48 442 cysts/g dry weight, and high cyst concentrations were recorded adjacent to the dumping site. This result suggests that anthropogenic activities such as ocean dumping s- timulate the growth of dinoflagellates in the Yellow Sea, which in turn leads to high levels of dinoflagellate cyst production.

关键词： Yellow Sea dumping site dinoflagellate cyst Alexandrium catenella/tamarense type Operculo- dinium centrocarpum

Sound transducer calibration of ambulatory audiometric system utilizing delta learning rule

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Journal of Central South University 2011年第6期18卷 2009-2014页

作者： KIM Kyeong-seop shin seung-won YOON Tae-ho LEE Sang-min LEE Insung RYU Keun ho School of Biomedical Engineering Konkuk University Xiu Solution Co. Ltd. Department of Electronic Engineering Inha University Department of Radio Communication Engineering Chungbuk National University Database/Bioinformatics Lab Chungbuk National University

An efficient calibration algorithm for an ambulatory audiometric test system is proposed. This system utilizes a personal digital assistant (PDA) device to generate the correct sound pressure level (SPL) from an audiometric transducer such as an earphone. The calibrated sound intensities for an audio-logical examination can be obtained in terms of the sound pressure levels of pure-tonal sinusoidal signals in eight-banded frequency ranges (250, 500, 1 000, 2 000, 3 000, 4 000, 6 000 and 8 000 Hz), and with mapping of the input sound pressure levels by the weight coefficients that are tuned by the delta learning rule. With this scheme, the sound intensities, which evoke eight-banded sound pressure levels by 5 dB steps from a minimum of 25 dB to a maximum of 80 dB, can be generated without volume displacement. Consequently, these sound intensities can be utilized to accurately determine the hearing threshold of a subject in the ambulatory audiometric testing environment.

关键词： calibration audiometric system pure-tonal sound sound pressure level heating threshold delta learning rule

Effects of dispersoid preforming via multistep sintering of oxide dispersion-strengthened CoCrFeMnNi high-entropy alloy

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Journal of Materials Science & Technology 2023年第9期140卷 187-200页

作者： seungHyeok Chung Ji ho shin ho Jin Ryu Department of Nuclear and Quantum Engineering Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea Central Research Institute Korea Hydro and Nuclear Power Co.Ltd.(KHNP)Daejeon 34101Republic of Korea

Dispersoid formation and microstructural evolution in an oxide dispersion-strengthened CoCrFeMnNi high-entropy alloy(HEA)using a newly designed multistep sintering process are *** proposed multistep sintering consists of a dispersoid preforming heat treatment of as-milled 0.1 wt%Y_(2)O_(3)-CoCrFeMnNi high-entropy alloy powders at 800℃,followed by sintering at 800–1000℃ under uniaxial *** the conventional single-step sintered bulk,the coarsened BCC Y_(2)O_(3)dispersoids mainly form with an incoherent interface with the HEA *** contrast,finer FCC Y_(2)O_(3)dispersoids,an atypical form of Y_(2)O_(3),are formed in the matrix region after multistep *** of FCC Y_(2)O_(3)disper-soids is initiated on the favorable facet,the{111}plane of the austenitic matrix,with the formation of a semi-coherent interface with the matrix during the dispersoid preforming heat treatment and it maintains its refined size even after *** is found that dispersoid preforming prior to sintering appears promising to control the finer dispersoid formation and refined grain structure.

关键词： Oxide dispersion strengthening High-Entropy alloy Multistep sintering Dispersoid preforming Microstructure evolution Interfacial structure

Random lasing detection of structural transformation and compositions in silk fibroin scaffolds

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Nano Research 2019年第2期12卷 289-297页

作者： SungYeun Yang Soocheol Kim Hyeln shin seung ho Choi Young L. Kim Chulmin Joo WonHyoung Ryu Department of Mechanical Engineering Yonsei University Yonsei-ro 50 Seodaemun-gu Seoul 03722 Republic of Korea Weldon School of Biomedical Engineering Purdue University West Lafayette Indiana 47907 USA Present address: Center of Bio Microsystems Korea Institute of Science and Technology (KIST) Hwarang-ro Seongbuk-gu Seoul 02792 Republic of Korea School of Electrical Engineering University of Ulsan Daehak-ro Nam-gu Ulsan 44610 Republic of Korea

In tissue engineering, microstructure and material composition of tissue scaffolds have major influences on the proliferation and differentiation of cells in the scaffolds. however, once tissue scaffolds implanted, it is extremely difficult to monitor the change of their microstructure and compositions during tissue regeneration. Here, we report how random lasing can be utilized to non-invasively monitor the structure and composition of scaffolds. We hypothesize that morphological and compositional change of silk fibroin (SF) scaffolds can be conveniently detected based on random lasing responses. Engineered SF scaffolds with hydroxyapatite (HAP) nanoparticles and controlled pore alignment were fabricated, and their random lasing responses were analyzed depending on the concentration of HAP nanoparticles and the degree of,:internal pore alignment. We also examined the real-time random lasing responses of porous SF scaffolds by applying a compressive force to' the scaffolds. Introduction of HAP nanoparticles lowered the lasing thresholds and narrowed the random lasing (RL) width dramatically, which :is likely due to the increase in heterogeneity in both refractive index and physical arrangement within the SF and HAP composites. The strong dependency of RL response on pore alignment was also measured and validated by numerical calculation with the finite element method (FEM).Finally, real-time monitoring of RL on compressed scaffolds demonstrated the possibility of using RL as a monitoring tool for structural change of SF scaffolds in vivo.

关键词： random lasing silk fibroin porous scaffolds aligned pore structure electrospinning hydroxyapatite