• Polymer(Korea)
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• v.24 no.6
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• pp.802-809
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• 2000

Counterion-specific helix formation and ion-selective transport of alkali metal chlorides (LiCl, NaCl, KCl, CsCl) were investigated for a poly(L-glutamic acid)(PLGA)/poly (vinyl alcohol)(PVA) blend membrane immersed in aqueous ethanol. The counterion specificity for helix formation of PLG alkali metal salts in the membrane was Li>Na>K>Cs. This specificity is ascribed to a contact ion-pair formation between the PLG carboxyl anion and the bound counterion, which depends on the energy balance between the electrostatic interaction and the desolvation. In aqueous ethanol, an appreciable ion-selectivity was observed for the permeability coefficient, i.e. Li$^{+}{\cdot}$Cl$^{-}$) formation between counterion and coion, and the latter to a specific interaction of diffusing counterions with polymer charges.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.104-104
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• 1999

The local heat transfer coefficient is experimentally investigated for the reflux condensation in a countercurrent flow between the steam-air mixture and the condensate. A single vertical tube has a geometry which is a length of 2.4m, inner diameter of 16.56mm and outer diameter of 19.05mm and is made of stainless steel. Air is used as a noncondensible gas. The secondary side is installed in the form of coolant block around vertical tube and the heat by primary condensation is transferred to the coolant water. The local temperatures are measured at 15 locations in the vertical direction and each location has 3 measurement points in the radial direction, which are installed at the tube center, at the outer wall and at the coolant side. In three different pressures, the 27 sets of data are obtained in the range of inlet steam flow rate 1.348 -3.282kg/hr, of inlet air mass fraction 11.8 -55.0%. The local heat transfer coefficient increases as the increase of inlet steam flow rate and decreases as the decrease of inlet air mass fraction. As an increase of the system pressure, the active condensing region is contracted and the heat transfer capability in this region is magnified. The empirical correlation is developed represented with the 165 sets of local heat transfer data. As a result, the Jacob number and film Reynolds number are dominant parameters to govern the local heat transfer coefficient. The rms error is 17. 7% between the results by the experiment and by the correlation.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.361-365
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• 2002

Rain-rate retrieval using the NOAA/AMSU (Advanced Microwave Sounding Unit) (Zaho et al., 2001) has been implemented at METRI/KMA since 2001. Here, we present the results of the AMSU derived rain-rate and validation result, especially for the rainfall associated with the tropical cyclone for 2001. For the validation, we use rain-rate derived from the ground based radar and/or rainfall observation from the rain gauge in Korea. We estimate the bias score, threat score, bias, RMSE and correlation coefficient for total of 16 tropical cyclone cases. Bias score shows around 1.3 and it increases with the increasing threshold value of rain-rate, while the threat score extends from 0.4 to 0.6 with the increasing threshold value of precipitation. The averaged rain-rate for at all 16 cases is 3.96mm/hr and 1.41mm/hr for the retrieved from AMSU and the ground observation, respectively. On the other hand, AMSU rain-rate shows a much better agreement with the ground based observation over inner part of tropical cyclone than over the outer part (Correlation coefficient for convective region is about 0.7, while it is only about 0.3 over the stratiform region). The larger discrepancy of tile correlation coefficient with the different part of the tropical cyclone is partly due to the time difference in between ice water path and surface rainfall. This results indicates that it might be better to develop the algorithm for different rain classes such as convective and stratiform.

• Nuclear Engineering and Technology
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• v.31 no.5
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• pp.486-497
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• 1999

The local heat transfer coefficient is experimentally investigated for the reflux condensation in a countercurrent flow between the steam-air mixture and the condensate, A single vertical tube has a geometry which is a length of 2.4m, inner diameter of 16.56mm and outer diameter of 19.05mm and is made of stainless steel. Air is used as a noncondensible gas. The secondary side has a shape of annulus around vertical tube and the lost heat by primary condensation is transferred to the coolant water. The local temperatures are measured at 11 locations in the vertical direction and each location has 3 measurement points in the radial direction, which are installed at the tube center, at the outer wall and at the coolant side. In three different pressures, the 27 sets of data are obtained in the range of inlet steam flow rate 1.348∼3.282kg/hr, of inlet air mass fraction 11.8∼55.0%. The investigation of the flooding is preceded to find the upper limit of the reflux condensation. Onset of flooding is lower than that of Wallis' correlation. The local heat transfer coefficient increases as the increase of inlet steam flow rate and decreases as the increase of inlet air mass fraction. As an increase of the system pressure, the active condensing region is contracted and the heat transfer capability in this region is magnified. The empirical correlation is developed by 165 data of the local heat transfer. As a result, the Jacob number and film Reynolds number are dominant parameters to govern the local heat transfer coefficient. The rms error is 17.7% between the results by the experiment and by the correlation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.8
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• pp.963-969
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• 2020

Cities in the region have a problem in that they cannot accurately monitor small areas because the number of air pollution is differently observed depending on variables such as population, season, traffic volume, and industrial complexes. In order to solve this problem, in this paper, comparative analysis was performed on small areas where representative air pollutants SO2, PM10, NO2, CO, and O3, which adversely affect the human body, are observed through coefficient of determination. In addition, based on Bonferroni's multiple comparative analysis, the air pollution level by period is shown. The map for the monitoring system was linked with the coordinates of each small city to visualize air pollutants for small cities based on the analysis data. Through this, it is possible to provide the user with a monitoring system of air pollutants for the region more precisely, and to prevent them from accidents that may occur due to air pollution in everyday life.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.6
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• pp.76-86
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• 1999

In this paper, it is shown that the car number plate are segmented and extracted more efficiently by using wavelet transform. A car image is decomposed by wavelet transform, and the high frequency image of the decomposed image are selected as feature images. Three selected feature images are synthesized of a single feature image, and a region including the plate is segmented by the correlation coefficient between the feature image and the synthesized image. For segmented plate region, the car plate region is extracted by deciding the Y-axis region composed by vertical region, the car plate region is extracted by deciding the Y-axis region composed by vertical histogram and the X-axis region composed by the variance histogram. Some experiment results of the various image and shown. It has been shown from the results with the high rate of 96% that the car number plates can be segmented and extracted more extractly and efficiently than converntional method.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.4
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• pp.331-337
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• 2011

We described for the production of cloud-free satellite sea surface temperature(SST) data around Northeast Asian using NOAA AVHRR(Advanced Very High Resolution Radiometer) SST data during 1990-2005. As a result of Markov model, it was found that the value of Markov coefficient in the strong current region such as Kuroshio region showed smaller than that in the weak current. The variations of average SST and regional difference of seasonal day-to-day SST in spring and fall were larger than those in summer and winter. In particular, the distribution of the regional difference appeared large in the vicinity of continental in spring and fall. The difference of seasonal day-to-day SST was also small in Kuroshio region and southern part of East Sea due to the heat advection by warm currents.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.3
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• pp.113-119
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• 2014

We carried out flow and structural response analysis of a box-type artificial reef (AR), which is made of concrete and structural steel. From the flow analysis, the wake region and drag coefficient were evaluated and accordingly, the structural analysis was performed to evaluate the stress and deformation of the target reef by considering the pressure field obtained from the flow analysis. The concept of wake volume was presented to quantitatively estimate the wake region and its variation according to flow direction and velocity. From the results, it is shown that the flow responses are only sensitive to the flow direction; the structural responses are sensitive to both of the flow velocity and direction although the magnitudes are negligible; and the wake volume became 3.52 times the AR volume with an optimum installation condition ($30^{\circ}$, flow direction) of the target unit.

• Korean Journal of Veterinary Research
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• v.30 no.3
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• pp.271-275
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• 1990

The tests related to red cell fragility were performed. Samples of blood anticoagulated with heparin were obtained from Korean native cattle in Chonbuk region abattoir, and classified by the district(Kun) with reference to breeding location. Hemolysis test for red cell fragility was performed with whole blood and glutathione peroxidase activity was measured spectrophotometrically. Blood concentration of selenium, inorganic component of glutathione peroxidase, was also determined fluorophotometrically. The results obtained were summerized as follows; 1. Percent hemolysis of erythrocytes ranged from 13.53 to 20.74%, and its mean Palue was low as $17.11{\pm}9.91%$. Means in all were not district(Kun) in Chonbuk region significantly different. 2. Glutathione peroxidase activity ranged from 2,881 to 4,000mU/ml, and high mean values, $3,352{\pm}1,872mU/ml$, reflected low percent hemolysis. 3. There was a highly negative correlation between the red cell fragility(Y) and blood glutathione peroxidase activity(X). The linear regression equation for these data was: Y=29.86-3.75X with a correlation coefficient of r=-.6886 (p<0.01) 4. Blood selenium concentration ranged from 0.16 to $0.24{\mu}g/ml$, and mean values was normal level as $0.2{\pm}0.11{\mu}g/ml$. 5. There was a highly positive correlation between blood selenium concentration(X), and blood glutathione peroxidase activity(Y). The linear regression for these data was: Y=230+15,790X, with a correlation coefficient officient of r=0. 8635.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.4
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• pp.133-140
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• 2006

The growth characteristics and properties of large size $SrAlF_5$ single crystals are described and compared with those of $BaMgF_4$. Transmission spectra in the vacuum ultraviolet wavelength region indicate a high transparency of $SrAlF_5$ (about 90% without considering surface reflection loses) down to 150 nm, on contrast to the optical loses observed for $BaMgF_4$. The ferroelectric character of $SrAlF_5$ is evidenced by the reversal of the spontaneous polarization in a hysteresis loop. The higher potential of $SrAlF_5$ in comparison with $BaMgF_4$ for the realization of all-solid-state lasers in the ultraviolet wavelength region by the quasi-phase matching (QPM) technique is pointed out. $SrAlF_5$, besides a higher grade of transparency, shows a nonlinear effective coefficient similar to that of quartz and uniaxial nature, on contrast to the one order smaller nonlinear coefficient and biaxial character of $BaMgF_4$. The refractive index of $SrAlF_5$ from the ultraviolet to the near-infrared wavelength region is measured by the minimum deviation method. The Sellmeier and Cauchy coefficients are obtained from the fits to the curves of the ordinary and extraordinary refractive indices, and the grating period for the first order QPM is estimated as a function of the wavelength. The poling periodicity for 193 nm SHG from 386 nm is $4{\mu}m$.