• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.3
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• pp.75-82
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• 2016

This study analytically reviewed the behavior of steel plate concrete (SC) walls subjected to forced vibration to investigate the effects of shape and arrangement spacing of studs on the behavior spacing of studs in SC wall were carried out. From the analyses, it was noted that the damping ratio obtained from the time history analyses showed overall high value in Half-power Bandwidth method and the lowest value in Fitted Exponential Curve method. And, in half of the design strength, the damping ratio presented approximately 3.0~4.2% and, in the design strength, it was approximately 4.1~5.2%. When the developed studs were used, the damping ratio was reduced slightly and it did not show consistent results between DS1 and DS2. When the distance between the studs increases more than necessary, it was also confirmed that the natural frequency was reduced and the damping ratio was increased.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.184-187
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• 2006

The effects of scandium content and extrusion parameters on Al-Zn-Mg-(Sc) alloys were examined. Three kinds of Al-Zn-Mg-(Sc) alloys with up to 0.30 wt.% Sc were prepared. The compression test was conducted to investigate the microstructure evolution during hot deformation. Despite of microstructural differences in the alloys, deformation behaviors were very similar. After extrusion at $350^{\circ}C$ with the ram speed of 15mm/sec, AA7075 showed a moderate surface quality compared with other Sc containing alloys, which was attributed to low flow stresses. AA7075 showed coarse-grained bands in surface region. With the ram speed of 1.5mm/sec at $350^{\circ}C$, the surface quality of the alloys was sound due to low friction stresses and deformation heating. As the Sc content increased, tensile strengths and elongations at room temperature improved.

• Korean Journal of Health Education and Promotion
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• v.29 no.1
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• pp.73-87
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• 2012

Objectives: The purpose of this study was to examine the compositional fitness and independence of the original six dimensions and the newly-designed six dimensions of Integrated Questionnaire for the Measurement of Social Capital[SC-IQ], and to explore the more simplified version for convenient use in public health-related social capital studies. Methods: This study reanalyzed social capital items included in a 2004 community health survey of K-city conducted by Hallym Health Services Research Center. Data was collected from 1,000 adults using core questions of SC-IQ. Explanatory factor analyses to all questions were done, and the new six dimensions were established. Confirmatory factor analyses[CFA] were done on the original and new six dimensions. And then reliability and validity test were done. SPSS 15.0 and AMOS 7.0 were used. Results: The final CFA module to the new SC-IQ exhibited Root Mean Square Error of Approximation[RMSEA] 0.028 and only compositional fitness and independence, and was composed of four dimensions and eight questions, and covers all elements of social capital including structural, cognitive, operational, outcome, bonding and bridging elements. Conclusion: This study demonstrates the utility of a new, simplified version of SC-IQ as well as its convenience.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.7
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• pp.1064-1068
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• 2002

In this paper, we introduce a hyper-chaos synchronization method using State-Controlled Cellular Neural Network(SC-CNN). We make a hyper-chaos circuit using SC-CNN with the n-double scroll. A hyper-chaos circuit is created by applying identical n-double scrolls with weak coupled method, to each cell. Hyper-chaos synchronization was achieved using drive response synchronization between the transmitter and receiver about each state in the SC-CNN. From the result of the recovery signal through the demodulation method in the receiver, We shown that recovery quality of state variable $$\chi$_3$ is superior to that of ${$\chi$_2}, {$\chi$_1}$ in secure communication.

• Journal of Microbiology and Biotechnology
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• v.10 no.2
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• pp.201-207
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• 2000

The freshwater green alga Chlorococcum sp. grew on NH_4^{+},{\;}NO_3^{-}$, urea, yeast extract, and peptone as the nitrogen source showing similar pattens of growth and secondary carotenoid (SC) production. However, the most suitable nitrogen source for the induction fo SC was urea. The dffects of nutrient levels (urea, phosphate, sulfate, ferrous iron, and salt) on growth and SC production were stydied by varying the concentration of each nutrient in batch cultures. High biomass production was achieved in cultures containing 20-28 mM urea, 4.8-10 mM phosphate, 1.6 mM sulfate, 70 mM phosphate, 1.6 mM sulfate, 170 mM NACl, and $50{\;}\mu\textrm{M}$ iron. The optimum concentrations of nutrients for biomass and for the SC accumulation in biomass were evaluated and the two media for achieving high biomass production and SC production were thus developed. The extent to which each parameter to stimulate the formation of SC in the alga were varied and the potentially improned SC prodution by manipulating the nutrient levels in the modified media were descussed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.3
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• pp.400-405
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• 1997

Lead scandium niobate powders were prepared by a molten salt synthesis method using KCl as a flux. Variations in phase formation and particle morphology were investigated for the temperature range $700^{\circ}C$ to $850^{\circ}C$. Pure $Pb(Sc_{1/2}Nb_{1/2})O_3$ perovskite phase was formed at $850^{\circ}C$ after 2hrs and the average particle size of powder was below 0.5 $\mu\textrm{m}$. The results are discussed with respect to DTA, X-ray diffraction, and microstructural characterization data.

• Journal of The Geomorphological Association of Korea
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• v.17 no.1
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• pp.39-48
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• 2010

This is a case study to research the environmental changes that occurred during the Latter Half of the postglacial age around the Basin of Onyang River in Asan, Korea. In line with this purpose, the author performed a pollen analysis and a radiocarbon dating on the deposits of alluvial fan around the upper Geumgok River, a tributary of Onyang River. Sampling point was at the altitude of about 67.5 meters, which belongs to the central zone of the cool temperate forest. The followings are the results of the study. The study area has passed through SC-I (the coniferous forest period in which Pinus was dominant), SC-II (the deciduous broad-leaved forest period in which Quercus and Castanea were dominant) and SC-III (the mixed conifer and deciduous broad-leaved forest period, in which Pinus, Quercus and Ulmus/Zelkova were dominant) respectively since about 3,000 yrB.P. SC-I period and SC-II period are presumed to be between about 3,000 and 2,000 yrB. P., and SC-III period to begin after 2,000 yrB.P. In comparison with the nationwide pollen zone during the postglacial age, SC-I and SC-II periods are contrasted with the R-IIIa zone and also the SC-III zone with the RIIIb zone. In addition, it is assumed that Pinus densiflora forest luxuriated there since 2,000 yrB.P. due to the destruction of forests, and that a lot of Fagopyrum pollen appeared; altogether, it was the so-called human interference period, from which forests began to be markedly destroyed. It is concluded that in those days inhabitants leaded agricultural life.

• Proceedings of the Korean Ceranic Society Conference
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• 2004.04b
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• pp.31.1-31.1
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• 2004

• Journal of the Korean Ceramic Society
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• v.44 no.12
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• pp.690-695
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• 2007

Scandia stabilized zirconia (ScSZ) is adapted for electrolyte material of solid oxide fuel cell (SOFC) because of its high ionic conductivity and chemical stability. ScMnSZ1 powder having a composition of $((ZrO_2)_{0.89}(Sc_2O_3)_{0.1}(MnO_2)_{0.01})$ is synthesized by ultrasonic spray pyrolysis (USP) method. Porous ScMnSZ1 powder is obtained by using a pore forming agent. Microstructure and morphology, particle size distribution of porous powder synthesized with 3wt% pore forming agent are investigated. Sintered ScMnSZ1 sample with ground fine powder are also investigated their microstructure and electrical conductivity. The electrical conductivity of sintered ScMnSZ1 samples with ground fine powder was 0.082 S/cm, 0.127 S/cm and 0.249 S/cm at $750^{\circ}C$, $800^{\circ}C$ and $900^{\circ}C$, respectively.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.4
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• pp.1-10
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• 2022

A vegetative filter strip (VFS) is one of the best management practices (BMPs) to reduce pollutant loads. This study aims to assess the effectiveness of VFS in dense upland field areas. The study areas are agricultural fields in the Maedae (MD), Gaa (GA), and Jaun (JU) watersheds, where severe sediment yields have occurred and the Korean government has designated them as non-point management regions. The agricultural fields were divided into three or four clusters for each watershed based on their slope, slope length, and area (e.g., MD1, MD2). To assess the sediment trapping (STE) and pesticide reduction efficiency (PRE) of VFS, the Vegetative Filter Strip Modeling System (VFSMOD) was applied with three different scenarios (SC) (SC1: VFS with rye vegetation; SC2: VFS with rye vegetation and a gentle slope in VFS range; and SC3: VFS with grass mixture). For SC1, there were relatively short slope lengths and small areas in the MD1 and GA3 clusters, and they showed higher pollutant reduction (STE>50%, PRE>25%). For SC2 and SC3, all clusters in GA and some clusters (MD1 and MD3) in MD show higher pollutant reduction (>25%), while the uplands in JU still show a lower pollutant (<25%). With correlation analysis between geographic characteristics and VFS effectiveness slope and slope length showed relative higher correlations with the pollutant efficiency than a area. The results of this study implied that slope and slope length should be considered to find suitable upland conditions for VFS installations.