• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.25-30
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• 2006

Marine traffics near Ulsan approaching waters are crossing and converged at the diverging point of No.1 route- No.2 route and No.1 route -No.3 route and are also concentrated at near No1. route approaching area and the headland of cape Gawnjeol. Because the number of berth will increase to 78 from 49 until 2011 due to additional developments, minor modification is expected for the water utilities. This study examined environmental conditions, marine accidental data, marine traffic capacity, traffic flow survery and fisheries zone status near Ulsan approaching water area. Finally, a questionaire survey was carried ou for experts and users to propose new plan.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.236-238
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• 1997

A cellular power amplifier using an APCVD(Atmospheric Pressure Chemical Vapor Deposition)-grown SiGe base HBT of ETRI has been designed with a linear simulation CAD. The Si/SiGe HBT with an emitter area of 2$\times$8${\mu}{\textrm}{m}$$^2$typically has a cutoff frequency(f$_{T}$) of 7.0 GHz and a maximum oscillation frequency(f$_{max}$) of 16.1 GHz with a pad de-embedding A packaged power Si/SiGe HBT with an emitter area of 2$\times$8$\times$80${\mu}{\textrm}{m}$$^2$typically shows a f$_{T}$ of 4.7 GHz and a f$_{max}$ of 7.1 GHz at a collector current (Ic) of 115 mA. The power amplifier exhibits a Forward transmission coefficient(S21) of 13.5 dB, an input and an output reflection coefficients of -42 dB and -45 dB respectively. Up to now the III-V compound semiconductor devices hale dominated microwave applications, however a rapid progress in Si-based technology make the advent of the Si/SiGe HBT which is promising in low to even higher microwave range because of lower cost and relatively higher reproducibility of a Si-based process.ess.ess.

• Journal of Forest and Environmental Science
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• v.33 no.3
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• pp.239-242
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• 2017

Although camera traps have been widely used to understand the abundance of wildlife in recent decades, the effort has been restricted to small sub-set of wildlife which can mark-and-recapture. The Random Encounter Model shows an alternative approach to estimate the absolute abundance from camera trap detection rate for any animals without the need for individual recognition. Our study aims to examine the feasibility and validity of the Random Encounter Model for the density estimation of endangered leopard cats (Prionailurus bengalensis) in Maekdo riparian park, Busan, South Korea. According to the model, the estimated leopard cat density was $1.76km^{-2}$ (CI 95%, 0.74-3.49), which indicated 2.46 leopard cats in $1.4km^2$ of our study area. This estimate was not statistically different from the previous leopard cat population count ($2.33{\pm}0.58$) in the same area. As follows, our research demonstrated the application and usefulness of the Random Encounter Model in density estimation of unmarked wildlife which helps to manage and protect the target species with a better understanding of their status.

• Journal of Environmental Science International
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• v.19 no.2
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• pp.157-170
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• 2010

Air mass recirculation is a common characteristic in the coastal area as a result of the land-sea breeze circulation. This study simulates the recirculation of air mass over the Gwangyang Bay using WRF-FLEXPART and offers a basic information about the effective domain size that can reflect recirculation. For this purpose, WRF is set up four nested domains and three cases are selected. Subsequently FLEXPART is operated on the basis of WRF output. During the clear summer days with weak wind speed, particles that emitted from Yeosu national industrial complex and Gwangyang iron works flow into emission sources because of the land-sea breeze. When land-sea breeze is strengthen, the recirculation phenomena appears clearly. However particles aren't recirculated under weak synoptic condition. Also plume trajectory is analyzed and as a consequence, the smallest domain area have to be multiplied by 1.3 to understand recirculated dispersion pattern of particles.

• The Korean Journal of Community Living Science
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• v.25 no.3
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• pp.383-388
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• 2014

This study was examined the physical characteristics (geometry, yield strength, thousand-seeds weight, true density, and moisture content) required for mechanization-related technologies such as (harvesting, washing, transport, and drying). Large differences in the size and shape of boxthorn berries(Jangmyeong, Bullo, Chungmyeong, and Hokwang) are used to analyze these physical properties. The average diameter, volume, surface area, and sphericity rate are calculated using long and short diameters of the boxthorn berry according to its variety. Hokwang has the largest measured surface area, and Bullo, the smallest. Average yield strength is 1.78 kPa and the mechanical pressure of soft boxthorn berries is not more than 1 kPa. Bullo has the highest true density. The optimum drying time for the measurement of moisture content is 4 hours at the drying temperature of $100^{\circ}C$.

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.631-636
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• 1997

This study was conducted to increase the adorption capacity of microporous carbon which is widely used as an adsorbent. After increasing the adsorption capacity of microporous carbon by heat-treatment, chromium($Cr^{+6}$) solution, which is the one of hazardous heavy metals, was selectively adsorbed on microporous carbon. Optimum temperature range for the heat-treatment of microporous carbon was $340{\sim}350^{\circ}C$, and the average specific surface area was measured as $1380m^2/g$ by BET (Brunauer-Emmett-Teller) method. The weight loss was about 10 percents during the heating to optimum temperature. However, It became a qualitative adsorbent due to a larger specific surface area. Removal of chromium($Cr^{+6}$) in solution by heat-treated microporous carbon was successfully carried out.

• Journal of the korean society of oceanography
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• v.35 no.2
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• pp.65-77
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• 2000

A simple but effective method has been developed for estimating diurnal and semi-diurnal tidal currents from trajectories of satellite-tracked drifters. The estimation method consists of separation of tidal current signals contained in the drifter trajectories, computation of undulations by diurnal and semi-diurnal currents, and correction of dominant diurnal and semi-diurnal tidal constituents. M$_2$ tidal currents estimated from drifter trajectories in the Yellow Sea are well consistent with those observed by moored current meters and this supports the validity of this method. We have constructed M$_2$ tidal current chart in the Yellow Sea by applying this method to available drifter trajectories collected during 1994-1998. According to this chart, M$_2$ current in the Yellow Sea rotates in the clockwise direction south of 35$^{\circ}$ 30'N but in the counterclockwise one to the north. Also it is found that the M$_2$ current is strong in the bank area northeast of the Changjiang River mouth and in the Korean coastal area, while it is weak in the deep central trough.

• Carbon letters
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• v.14 no.3
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• pp.180-185
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• 2013

In this study, activated carbons nanofibers (ACNFs) were prepared from polyacrylonitrile-based nanofibers by physical ($H_2O$ and $CO_2$) and chemical (KOH) activation. The surface and structural characteristics of the porous carbon were observed by scanning electron microscopy and X-ray diffraction, respectively. Pore characteristics were investigated by $N_2$/77K adsorption isotherms. The specific surface area of the physically ACNFs was increased up to $2400m^2/g$ and the ACNFs were found to be mainly composed of micropore structures. Chemical activation using KOH produced ACNFs with high specific surface area (up to $2500m^2/g$), and the micropores were mainly found in the ACNFs. The physically and chemically ACNFs showed both mainly type I from the International Union of Pure and Applied Chemistry classification.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.spc1
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• pp.223-230
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• 2006

We investigated the spring and summer community structure of meiobenthos in a tidal-falt near Iwon, Korea, in 2002 and 2003. In total, 12 meiofaunal groups were found in the study area among which nematodes were the most dominant. Benthic foraminiferans, harpacticoid copepods, polychaetes, and crustacean nauplli were also dominant groups at all sites. The total density of meiobenthos at each station was be 246-2,177 ind./$10cm^2$. As the depth of sediment increased, the density of meiobenthos at each station gradually decreased. Changes in the vertical distribution of meiobenthos in the study area occurred mainly near the sediment surface (0-1 cm). Generally, between spring and summer the density of nematodes increased, and the density of other dominant meiofaunal groups (benthic harpacticoids, crustacean nauplii, benthic foraminiferans) decreased near the sediment trap the control site of sediment traps compared to that at the control site. The results of cluster and multidimensional scaling plots indicate that the meiofaunal community changed following construction of a low artificial wood groin structure.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.6
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• pp.640-652
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• 2007

The MM5, RAMS and WRF, meteorological models have provided the dynamical parameters as inputs to air quality model. A major content of this study is that significant characteristics of three models for high-ozone occurrence analyze for surface wind and air temperature fields and compare with observation data in Seoul metropolitan area. An analysis of air temperature field revealed that location of core in high temperature of MM5 and WRF differed from that of RAMS. MM5 and WRF indicated high temperature in Seoul but RAMS represented it on the outskirts of Seoul. MM5 and WRF were underestimated maximum temperature during daytime but RAMS simulated similar value with observation data. Surface wind field with three models, it was shown many differences at horizontal distribution of wind direction. RAMS indicated weak wind speed in land and strong sea breeze at coastal areas than MM5 and WRF. However wind speed simulated by three model were overestimated during both daytime and nighttime.