• Journal of the Korean Society of Marine Environment & Safety
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• v.5 no.2
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• pp.57-65
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• 1999

The in situ observations and the seawater analyses were conducted at all seasons from July 1996 to April 1999 for the purpose of describing the characteristics of seasonal variations of water quality in Mokpo harbour, Korea. Vertical stratification started to be formed in water column in spring, developed in summer and disappeared in fall. In summer, vertical density distribution of water column was found to be in stable structure with lower temperature and higher salinity of bottom water, and the vertical mixing of water between surface and bottom layers was restricted. In winter, however, surface water was found to be similar to bottom water in temperature and salinity, and water column was in unstable structure and in well-mixed condition between surface and bottom waters. The saturation percentage of dissolved oxygen(DO) in bottom water of inner part of Mokpo harbour at all seasons was shown to be decreased to the third grade or under the third grade of Korean standards of seawater quality. In particular, dissolved oxygen was oversaturated in surface water and undersaturated in bottom water in summer, due to stratification and organic pollution. The difference of DO concentration between surface and bottom waters was found to be greater in spring and summer than in fall and winter, due to stratification and photosynthesis of phytoplankton. The concentrations of chemical oxygen demand(COD) over the entire waters of Mokpo harbour were found to fluctuate from below the third grade to the first grade of Korean standards through all seasons and COD concentrations of same seasons were shown to be different year after year. In particular, in view of COD, the annual average seawater quality of Mokpo harbour was evaluated to be in third grade of Korean standards, due to organic pollution. The average COD of surface water was greater than that of bottom water in spring and summer, due to the autochthonous COD caused by production of phytoplankton in surface waters, while the average COD of surface water was similar to that of bottom water in fall and winter, due to the vertical mixing of water between surface and bottom layers.

• Journal of information and communication convergence engineering
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• v.9 no.6
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• pp.743-746
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• 2011

An implementation for surface EMG network analysis and vertical control system of robotic arm is presented in this paper. The transmembranes are simulated by equivalent circuit and cable equation for propagation to be converted to circuit networks. The implementation is realized to be derived from the detecting EMG signal from 3 electrodes, and EMG transmembrane signals of human arm muscles are detected by several surface electrodes, high performance amplifier and filtering, converting analog to digital data and driving a servomotor for spontaneous robotic arm. The system is experimented by monitoring multiple steps vertical control angles corresponding to biceps muscle movement. The experimental results are that the vertical moving control level is measured to around 2 degrees and mean error ranges are lower 5%.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.645-647
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• 2009

We investigated vertical liquid crystal (LC) alignment effects of a self-assembled-monolayer (SAM) prepared on an anisotropic $SiO_2$ surface where the field-induced LC reorientation produced a uniform single domain texture. We compared the results with the homeotropic-to-random planar reorientation results shown in LCs aligned on a SAM surface prepared on an isotropic $SiO_2$ surface.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.7
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• pp.158-166
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• 1996

In this study, a flexible disk grinding process is applied in order to produce high precision product. A new model was developed considering feed motion along horizontal and vertical direction. Different types of feed speed variation was tested with respect to distinct process stages in order to achieve flat surface. It was observed that highest order polynomial form for both horizontal and vertical feed speed variation among the proposed categories produced surface close to flat one. Disk deflection trend during the process was visualized confirming the proposed scheme. Cutting force and VRR(volume removal rate) was observed as an aid to process planning.

• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.4
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• pp.80-91
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• 1982

To precict the suspended sediments which are 80% of total sediments in a flood disch- arge, an equation representing vertical distribution of sediment concentration was derived based upon the diffusion theory and the logalithmic velocity distribution function in the tubulent flow mechanism. The hypothesis that the uniform mass transfer is occurred at upper part along the center line of water depth, was established as a preconition to solve the problem. The theorecal and the observed values were compared. And the theoretical equation was modified to be fit the theoretical values the observed values. Observed results are as follow; 1) Equation 12) is the theoretical equation representing the vertical concentration distri- bution of suspended sedimenta 2) Rous&exonential type vertical concentration distribution equation shows signification errors near the water surface. But the equation 12) shows substation cocentration values near the water surface. 3) Equation 15) is the modified theoretical equation which is possible to predict the vertical concentration distribution of suspended sediments.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.4
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• pp.426-434
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• 1988

Series expansion is applied to solve the laminar boundary layer equations for the problem of natural convection from vertical cylinder with uniform surface heat flux. The series in terms of transverse curvature parameter ${\xi}$ is extended to five terms and is well converged by applying the Shanks transform twice. In case of natural convection from a vertical cylinder heated with uniform surface heat flux, it is possible to consider the vertical cylinder as vertical plate under the condition of D/L${\geq}$A/$(Gr_L^*)^{1/5}$, where A is in the range of 5.7~55.2. Also, mean Nusselt number ${\overline{Nu_L}}$ can be represented as $C_1(Ra_L^*)^{1/5}$, where $C_1$ is a constant which depends on Pr and is in the range of 0.5~0.8.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.2
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• pp.177-189
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• 2010

In order to incorporate correctly the large or local scale circulation in an atmospheric model, a nudging term is introduced into the equation of motion. The MM5 model was used to assess the meteorological values differences in each case, during ozone episode days in Gwangyang bay. The main objective of this study is to investigate the effect of horizontal and vertical flow fields according to the surface and vertical observation data assimilation by upper wind conditions. Therefore, we carried out several numerical experiments with various parameterization methods for nudging coefficient considering the upper wind conditions (synoptic or asynoptic condition). Nudging considering the synoptic and asynoptic nudging coefficient does have a clear advantage over dynamic initialization, therefore appropriate limitation of these nudging coefficient values on its upper wind conditions is necessary before making an assessment. Obviously, under the weak synoptic wind, there was apparent advantage associated with nudging coefficient by the regional difference. The accuracy for the prediction of the meteorological values has been improved by applying the appropriate PBL (Planetary Boundary Layer) limitation of circulation.

• Korean Journal of Optics and Photonics
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• v.20 no.6
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• pp.339-345
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• 2009

The high power and single mode vertical cavity surface emitting laser(VCSEL)s with photonic crystal structures have been proposed and fabricated by reducing substantially the hole numbers used in the photonic crystal structures. It is found that only six holes enable VCSELs to operate a single mode and the reliability can be enhanced by filling the holes with polyimide. The single mode lasing characteristics were analyzed by varying the oxide aperture and the hole diameter in photonic crystal structures. As a result, the single mode lasing can be stably obtained in the photonic crystal vertical cavity surface emitting lasers.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.1
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• pp.57-74
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• 2009

In order to clarify the vertical ozone distribution in planetary boundary layer of coastal area with complex terrain, an observation campaign was carried out around Gwangyang Bay with dense pollutant emission sources during two days from June, 4 2007. For this observation are Radiosonde, SODAR(SOnic Detection And Ranging) and Tethered ozone sonde were employed. The surface meteorological and photochemical observation data provided by AWS (Automatic Weather System) and AQMS (Air Quality Monitoring System) were also applied for analysis. Synoptic condition is strongly associated with lower level ozone distribution in complex terrain coastal area. Since mesoscale circulation induced by difference of characteristics of land and sea and orographic forcing is predominant under calm synoptic condition, vertical distribution of ozone is complicate and vertical ozone concentration greatly fluctuated. However in second day when synoptic influence become strong, ozone concentration in lower levels is vertically uniform regardless of observation level. This results in vertical observation indicates that vertical ozone distribution is often determined by synoptic condition and also affects surface ozone concentration.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.130-130
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• 2011

vertical light-emitting diodes의 표면을 건식과 습식 두 가지 공정을 통해 식각하여 roughening을 주었고, 또한 이 고정으로 인해 표면이 전체적으로 거칠기를 가지므로써 외부 양자 효율의 증가를 기대하였다.