• 한국해양학회지
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• v.20 no.3
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• pp.20-29
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• 1985

Sediment transport by tidal currents as well as the distribution and properties of intertial surface sediments are investigated using the data obtained from an anchor station on the main tidal channel and 56 tidal flat surface samples. Sedimentation in the intertidal zone appears to occur mainly during the spring tide period in this environment. The tidal flat can be classified into three depositional facies. The tidal flat deposits are ubiquitously bioturbated by various bottom dwelling organisms among which the crabs and polychaetes predominate. Average trace metal contents of the intertidal surface sediments are: 74.8 ppm co, 67.8 ppm Ni, 32.6 ppm Cu and 30.7 ppm Pb. Compared with the northen Kyeonggi Bay bottom sediments, these contents are significantly high, except for Pb.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.1
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• pp.135-153
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• 2016

This study is aimed at grasping improvement factors of Cheonho Park, Gandaemae Park and Hunlyunwon Park as barrier free friendly parks. For this study, current status of parks, users' state and satisfaction were analyzed in October, 2014 and September, 2015. To detect current status, period of designing, whole size, facility pavement green space area, and main spaces were examined. As for BF status, mediation facilities, leading and guidance facilities, convenient facilities and BF pedestrial passage were analyzed. Also, It examined user behavior and satisfaction by accessibility, convenience and safety items. As a result of status analysis, three parks were designed in 1997~1998. The size of parks were $15,180m^2{\sim}26,697m^2$. As for mediation facilities, the slopes of walking-passage in Cheonho Park and Gandaemae Park were flat. The rate of leading-guidance facilities was 72.7%~93.4%. In the three parks, the effective width of safe pedestrian space within BF pedestrial passages was more than 1.8m. In Cheonho Park and Gandaemae Park, more than 50% of soil and urethane were used as paving materials. Users were the most satisfied with accessibilities in Cheonho Park due to flat-typed walking passages. In convenience, when it comes to using benches and pergolas, it showed significantly different satisfaction in every park. In safety, there were also considerable difference in every park. Overall, it was analysed that the satisfaction with information for safety and facilities was significantly low. Against this backdrop, this study suggests three considerations to recreate parks as barrier free friendly parks. 1) Flat-typed walking passages and enough parking areas near parks should be constructed. 2) Additional rest furniture for convenience should be installed and complemented. 3) Walking oriented-spatial safe facilities for safety should be differently supplemented.

• Membrane Journal
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• v.25 no.4
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• pp.320-326
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• 2015

In this study, permeation experiments were carried out using the symmetric and asymmetric sinusoidal flux continuous operation (SFCO) modes for the submerged flat sheet membrane in the 0.5 wt% emulsion type cutting oil solution. The effective area and nominal pore size of the used microfiltration membrane were $0.02m^2$ and $0.15{\mu}m$, respectively. The emulsion cutting oil was rejected over 99% based on turbidity. Transmembrane pressure increased lower as the aeration rates increased. The symmetric SFCO mode was a little more effective than the symmetric SFCO mode in low permeate flux between 10 and $15L/m^2{\cdot}h$. However, the symmetric SFCO mode was shown very effectively in high permeate flux between 25 and $30L/m^2{\cdot}h$.

• Membrane Journal
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• v.25 no.1
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• pp.7-14
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• 2015

In this study transmembrane pressure (TMP) was measured with respect to operational time in order to estimate fouling of the submerged membrane in the membrane bioreactor(MBR). The microfiltration flat sheet module which has $0.02m^2$ of effective area and $0.15{\mu}m$ nominal pore size was submerged in the activated sludge solution of MLSS 5,000 mg/L. The permeate experiments were carried out simultaneously to compare TMP of the run/stop (R/S) with that of the sinusoidal flux continuous operation (SFCO). TMP for SFCO mode was up to 93% lower than that of R/S mode, and the effect of TMP drop reduced as permeate flux increased. Also, TMP of the SCFO mode was maintained below 40% of the limited operating TMP 55 kPa until the permeate operational time extended to longer than 5 times for the case as the coagulant $FeCl_3$ was dosed into the activated sludge solution with 500 mg/L concentration.

• Journal of the Korean earth science society
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• v.33 no.1
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• pp.1-10
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• 2012

Analysis on high-resolution seismic and core data reveals that the sedimentary strata in Gyeonggi Bay consists of four sedimentary units (Unit I-IV, from top to bottom) formed during the late Quaternary period. Unit I is interpreted as sediments of tidal flat and channel-fill deposits, formed during the Holocene transgression. Unit II is divided into shallow-marine facies unit in offshore area and channelized fluvial to estuarine facies unit in nearshore sand ridge and tidal flat. Unit III is considered as tidal flat deposits with the uppermost severely weathered and oxydized layers. This unit is composed of shallow marine sedimentary successions formed during the MIS-5 highstand. The lowermost Unit IV rests on Mesozoic basement rocks, considered as the shallow marine and shelf deposits formed before the MIS-5 lowstand.

• Journal of the Korea Fashion and Costume Design Association
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• v.5 no.1
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• pp.59-71
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• 2003

The purpose of this study is to provide for the basic data useful to the development of a quality brassiere featuring a good wearing feeling and an effect of reinstating and correcting breast shape. For this purpose, 220 adult women aged between 20 and 59 were sampled to survey their perceived and actual breast shapes. The results of this study can be summarized as follows; 1. Most adult women correctly perceive the changes of their breast shapes as they become older. However, the younger women tend to evaluate their breast as larger than their actual sizes, being more dissatisfied with their breast shapes than older women, while wanting their constitution to be more high and slim. In short, there is a little difference between their perceived and actual breast shapes. 2. The breast shape perceived most by the adult women is "droopy type I"(37.7%), followed by "conical type"(21.8%), "flat type"(16.8%), "semi-circular"(10.8%), "droopy type II"(8.6%) and "extruded type"(5.0%) in their order. The younger women tend to perceive their breasts as "flat", "conical" or "semi-circular", while the older women tend to perceive their breasts as "droopy". 3. According to the increase of age, the items of height were decreased and items of width, depth, circumference and length were increased, being obser and breast point were drooped. so volume and bottom area of breast of 40ㆍ50's women's age group were larger than 20?30's women's age group and breast point width of 40ㆍ50's women was being wider by increase of interior dimensions of breast.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.3
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• pp.245-250
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• 2006

The effects of aliphatic hydrocarbons (n-hexadecane and n-dodecane) on the volumetric oxygen mass transfer coefficient $(k_L\;a)$ were studied in flat alveolar airlift reactor and continuous stirred tank reactors (CSTRs). In the flat alveolar airlift reactor, high aeration rates (>2vvm) were required in order to obtain efficient organic-aqueous phase dispersion and reliable $k_La$ measurements. Addition of 1% (v/v) n-hexadecane or n-dodecane increased the $k_La$ 1.55- and 1.33-fold, respectively, compared to the control (superficial velocity: $25.8{\times}10^{-3}m/s$, sparger orifice diameter: 0.5 mm). Analysis of the gas-liquid interfacial area a and the liquid film mass transfer coefficient $k_L$ suggests that the observed $k_La$ increase was a function of the media's liquid film mass transfer. Addition of 1% (v/v) n-hexadecane or n-dodecane to analogous setups using CSTRs led to a $k_La$ increase by a factor of 1.68 and 1.36, respectively (superficial velocity: $2.1{\times}10^{-3}m/s$, stirring rate: 250 rpm). These results propose that low-concentration addition of oxygen-vectors to aerobic microbial cultures has additional benefit relative to incubation in purely aqueous media.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.5
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• pp.501-509
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• 2016

In this study, a flat-type photocatalytic reactor is applied under solar irradiation for simultaneous treatment of target pollutants: reduction of Cr(VI) to Cr(III) and oxidation of EDCs (BPA, EE2, E2). An immobilized type of photocatalyst was fabricated to have self-grown nanotubes on its surface in order to overcome limitations of powdery photocatalyst. Moreover, Ti mesh form was chosen as substrate and modified to have both larger surface area and photocatalyst content. Ti mesh was anodized at 50V and $25^{\circ}C$ for 30min in the mixed electrolytes ($NH_4F-H_2O-C_2H_6O_2$) and annealed at $450^{\circ}C$ for 2 hours in ambient oxygen to have anatase structure. Surface characterization was done with SEM and XRD methodologies. Fabricated NTT was applied to water treatment, and coexisting Cr(VI) and organics (EDCs) enhanced each other's reactions by scavenging holes and electrons and thus impeding recombination. Also, several experiments were conducted outdoor under direct sunlight and it was observed that both solar-tracking and applying modified photocatalyst were proven to enhance reaction efficiency.

• Journal of the Korean Institute of Intelligent Systems
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• v.27 no.2
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• pp.119-125
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• 2017

The mud flat in Korea is the geographical feature generated from the sediment of rivers of Korea and China and it is the important topography for pollution purification and fishing industry. The mud flat is difficult to access such that it requires the aerial survey for the high-resolution spatial information of the area. In this study we used drones instead of the conventional aerial and remote sensing approaches which have shortcomings of costs and revisit times. We carried out GPS-based control point survey, temporal image acquisition using drones, bundle adjustment, stereo image processing for DSM and ortho photo generation, followed by co-registration between the spatio-temporal information.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.7
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• pp.937-944
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• 1999

The near-wall flow structures of turbulent boundary layer over riblets having semi-circular grooves were investigated experimentally for the drag decreasing ($s^+=25.2$) and drag increasing ($s^+=40.6$) cases. The field of view used for tho velocity field measurement was $6.75{\times}6.75mm^2$ in physical dimension, containing two grooves. One thousand instantaneous velocity fields over the riblets were extracted for each case of drag increase and decrease. For comparison, five hundreds instantaneous velocity fields over a smooth flat plate were also obtained under the same flow conditions. To see the global flow structure qualitatively, the flow visualization was also performed using the synchronized smoke-wire technique. For the drag decreasing case ($s^+=25.2$), most of the streamwise vortices stay above the riblets, interacting with the riblet tips. The high-speed in-rush flow toward the riblet surface rarely influences the flow inside tho riblet valleys submerged in the viscous sublayer. The riblet tips seem to impede the spanwise movement of the longitudinal vortices and induce secondary vortices. The turbulent kinetic energy in the riblet valley is sufficiently small to compensate the increased wetted area of the riblets. In addition, in the logarithmic region, the turbulent kinetic energy are small or almost equal to that of a smooth flat plato. For the drag increasing case ($s^+=40.6$), however, the streamwise vortices move into the riblet valley freely, interacting directly with the riblet inner surface. The penetration of the high-speed in-rush flow on the riblets increases tho skin-friction. The turbulent kinetic energy is increased in the riblet valleys and even in the outer region compared to that over a flat plate.