• Journal of the korean society of oceanography
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• v.37 no.1
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• pp.10-19
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• 2002

The detailed structure of a tidal front and its ebb-to flood variation in the main tidal channel of the Kyunggi Bay in the mid-west coast of Korea were investigated by analyzing CTD data and drifter trajectories collected in late July 1999. A typical tidal front was formed in water about 60 m deep at the mouth of the channel. Isotherms and isohalines in the upper layer above the seasonal pycnocline in the offshore stratified zone inclined upward to the sea surface to form a surface front, while those in the lower layer declined to the bottom front. The location of the front is consistent with $100 S^3/cm^2$ of the mixing index H/U defined by Simpson and Hunter (1974), where H is the water depth and U is the amplitude of tidal current. The potential energy anomaly in the frontal zone varied at an ebb-to flood tidal cycle, showing a minimum at slack water after ebb but a maximum at slack water after flood. This ebb-to flood variation in potential energy anomaly is not accounted for by the mixing index. We conclude that on- and offshore displacement of the water column by tidal advection is responsible for the ebb-to-flood variation in the frontal zone.

• Journal of the Korean Geotechnical Society
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• v.33 no.11
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• pp.97-104
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• 2017

A bentonite mixing with local soil widely used as liner layer for landfill should have low permeability less than $1{\times}10^{-7}cm/s$. But there are several limitations of bentonite used as liner layer, such as drying shrinkage cracking, ineffective waterproof ability under salt water condition like flocculation under sea water. The purpose of this research is the development of a salt resistance bentonite by mixing sepiolite and guar gum to overcome the weak points of bentonite to get high water resistance capacity and permeability coefficient below $1{\times}10^{-7}cm/s$ under salt water condition. After having performed drying shrinkage cracking test, swelling index test, compaction test, and hydraulic conductivity test we confirmed the optimal mixing ratio of materials and evaluated the performance of materials.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.2
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• pp.196-205
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• 2008

Variability in vertical ozone and meteorological profiles was measured by 2Z electrochemical concentration cells (ECC) ozonesonde at Bangyi in Seoul ($37.52^{\circ}N$, $127.13^{\circ}E$) during June $6{\sim}9$, 2003 in odor to identify the vertical distribution of ozone and its relationship with the lower-atmospheric structure resulted in the high ozone concentrations near the surface. The eight profiles obtained in the early morning and the late afternoon during the study period clearly showed that the substantial change of ozone concentrations in lower atmosphere(${\sim}5\;km$), indicating that it is tightly coupled to the variation of the planetary boundary layer (PBL) structure as well as the background synoptic flow. All profiles observed early in the morning showed very low ozone concentrations near the surface with strong vertical gradients in the nocturnal stable boundary layer due to the photochemical ozone loss caused by surface NO titration under very weak vertical mixing. On the other hand, relatively uniform ozone profiles in the developed mixing layer and the ozone peaks in the upper PBL, were observed in the late afternoon. It was noted that a significant increase in ozone concentrations in the lower atmosphere occurred with the corresponding decrease of the mixing height in the late afternoon on June 8. Ozone in upper layer did not vertically vary much compared to that in PBL but changed significantly on June 6 that was closely associated with the variation of synoptic flows. Interestingly, heavily polluted ozone layers aloft (a maximum value of 115 ppb around 2 km) were formed early in the morning on 6 through 7 June under dominant westerly synoptic flows. This indicates the effects of the transport of pollutants on regional scale and consequently can give a rise to increase the surface ozone concentration by downward mixing processes enhanced in the afternoon.

• International Journal of Concrete Structures and Materials
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• v.10 no.sup3
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• pp.65-74
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• 2016

During concrete pumping, the migration and redistribution of particles occur in a pipe and the lubrication layer that forms between the bulk concrete and the pipe wall is the governing factor determining the flow behavior. In order to identify flow behavior of pumping, in this study, the viscoelastic properties related to the microstructural behavior of a flocculated suspension were examined by using dynamic oscillatory measurements. Cement paste is assumed to be a constituent material of the lubrication layer and ten cases of mixing design are employed by changing the proportions of mineral admixtures. The relationship between the yield stress obtained from the steady shear test and the dynamic modulus resulted from the oscillatory shear measurement was derived and the implications of the correlation are discussed. Moreover, based on the investigation of the viscoelastic properties with oscillatory measurements, the initial behavior of pumped concrete was analyzed systematically.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1360-1363
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• 2007

The bus electrode is composed of two layers. One is the black matrix(BM) and silver layer is formed on top of black layer. The BM paste is made by mixing $Co_3O_4$ black powder with photosensitive vehicle and rheological additives. In this work we studied the effect of $Co_3O_4$ black powder and glass frit on the rheological property of photosensitive BM paste. We also examined how the size and content of black powder and glass frit affect the transmittance and reflectance of the BM layer after sintering.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.565-570
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• 1998

An interfacial condensation heat transfer phenomenon in a steam/water countercurrent stratified flow in a nearly horizontal pipe has been experimentally investigated. The present study has been focused on the measurement of the temperature and velocity distributions within the water layer. In particular, the water layer thickness used in the present work is large enough so that the turbulent mixing is limited and the thermal stratification is established. As a result, the thermal resistance of the water layer to the condensation heat transfer is increased significantly. An empirical correlation of the interfacial condensation heat transfer has been developed. The present correlation agrees with the data within $\pm$15%

• Korean Journal of Plant Resources
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• v.18 no.3
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• pp.512-517
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• 2005

To establish the economical cultivation method of Gastrodia elata Blume by controlling the shading rate and the mixing ratio of recycling spawn bed logs, a serial experiment was carried out. When G. elata was grown in the field with no shading, the yield of spawn tuber was higher than that of tuber of G. elata. The yield of G. elata was high in the rainproof green house covered with one layer of $95\%$ shading net, in the rainproof green house covered with two layers of $95\%$ shading net, and in the field with no shading, in that order. In the case of mixing ratio of recycling spawn bed logs, the yield was high in the fresh logs, in the mixing ratio of 2:1, and the ratio of 1:1, in that order. The income of the rainproof green house covered with one layer of $ 95\%$ shading net which brought the best yield was $81\%$ in the mixing ratio of 2:1 over the fresh logs.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.194-199
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• 2002

Eight Korean wheat cultivars were milled and evaluated for the properties of white layer cake-making, compared to a commercial soft wheat flour. Milling yields of the Korean wheat cultivars ranged from 62.5 to 71.8%. The protein and ash contents of flours milled from Korean wheat cultivars ranged from 7.70 to 10.58% and 0.51 to 0.71%, respectively. Woorimil, Alchanmil and Olgeurumil flours, having low protein content, showed very weak mixing characteristics. Even though Eunpamil and Geurumil flours showed longer mixing time and higher peak height, they had week dough stability. Slight differences in pH and specific gravity of cake batter were observed among the Korean wheat flours. Cake volume measured by rapeseed displacement was in the range of $837.5{\sim}952.5\;cc$. Alchanmil flour demonstrated the highest specific volume of 2.40, and the other domestic flours symmetrical and uniform than those with the commercial soft wheat flour. Volume of white layer cakes was negatively affected by flour protein content and somewhat associated with crumb softness. Crumb color of cakes prepared with domestic wheat flours was slightly darker and more yellowish. Hardness of fresh cakes prepared with domestic flours ranged from 307.33 to 416.60 $g_f$.

• Journal of Environmental Science International
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• v.21 no.7
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• pp.815-824
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• 2012

The purpose of this study was to analyze the meteorological characteristics of wintertime high PM10 concentration episodes in Busan. $PM_{10}$ concentration has been reduced for the past four years and recorded near or exceeded 100 ${\mu}g/m^3$ (national standard of $PM_{10}$). High concentration episodes in Busan were 6 case, $PM_{2.5}/PM_{10}$ ratio was 0.36~0.39(mean 0.55). High $PM_{10}$ concentration occurred during higher air temperature, more solar radiation and sunshine, lower relative humidity, and smaller cloud amount. Synoptically, it also occurred when Busan was in the center or the edge of anticyclone and when sea breeze intruded. An analysis of upper air sounding showed that high $PM_{10}$ concentration occurred when surface inversion layer and upper subsidence inversion layer existed, and when boundary layer depth and vertical mixing coefficient were low. An analysis of backward trajectory of air mass showed that high $PM_{10}$ concentration was largely affected by long range transport considering that it occurs when air mass is intruded from China.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.209-209
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• 2010

Multiferroic properties of $BaTiO_3-CuFe_2O_4$ thin films grown on highly-textured Pt(111)/$TiO_2/SiO_2$/Si(100) substrates were studied. $CuFe_2O_4$ ceramic target was synthesized by mixing oxide powders of CuO, $Fe_2O_03$, $BaTiO_3$ ceramic target was also prepared separately. The film structure was of bi-layer type, where $BaTiO_3$ layer lies underneath of $CuFe_2O_4$ layer, where both layers were grown by pulsed laser deposition technique. We will report the ferroelectric and magnetic properties of $BaTiO_3-CuFe_2O_4$ bi-layer films in some detail.