• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.654-659
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• 2018

In this study, continuous long-term observation is implemented with an ocean radar. Ocean radar conducts remote observation (combined) with ground-based radars, which enable a series of simultaneous observations of an extensive range of the coast with high frequency. An ocean radar for continuous long-term observation is operated at Samcheok on the east coast of Korea. Samcheok experienced tsunami damage in recent years and is the location of a nuclear power plant. In order to examine the reliability of the ocean radar, a pressure-type wave gauge, ultrasonic wave gauge, and ocean buoy are installed for the purpose of data comparison and verification. The ocean radar used in this study is an array-type HF-RADAR named WERA (WavE RAdar). The analysis of the data obtained from continuous long-term observations showed that the radar observations were in agreement with more than 90% of the wave data collected within a 25 km range from the center of two sites. Less than 1% of the entire observation data was unmeasured by the time series analysis. As a result of comparing the radar data with the direct observations made by the wave gauge, it was inferred that the RMS deviation is less than 20cm and the correlation coefficient was in the range of 0.84 ~ 0.87. Moreover, supported by such observations, a comprehensive monitoring system is being developed to provide the public with real-time reports on waves and currents via the internet.

• The Korean Journal of Physiology
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• v.2 no.1
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• pp.31-38
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• 1968

Total body fat measurement by means of skinfold thickness was performed in 94 secondary school boys. Hydrostatic weighing was made on the same subject and corrected for residual volume in lung. Skinfold thicknesses at four sites, namely, back, waist, arm and abdomen, were compared with total body fat calculated from the equation given by Keys and Brozek and regression equation were computated. In 48 middle school boys aged between 13 and 16 years and 46 high school boys aged between 16 and 19 years, skinfold thicknesses increased at all 4 sites as age increased. The body density, however, showed different pattern. In middle school ages, body density showed little variation. Density in 13-14 years was 1.0608, in 14-15 years 1.0578 and in 15-16 years 1.0546. In high school ages density in-creased abruptly to 1.0703 (16 yr.), 1.0730 (17 yr.) and 1.0740 (18 yr.). Subsequently 15 years was a boundary for density change and total body fat change. In middle school boys as a group of 48 the observed values were: density: 1.0562, total body fat: 15.9%, mean skinfold thickness at four sites: 6.02 mm. The coefficient of correlation between mean skinfold thickness and density were r=-0.759 and r=0.781 with %fat. The regression equations were : Body $density=-0.00527{\times}Mean$ skinfold thickness (mm)+1.0879, %Fat=$1.933{\times}Mean$ skinfold thickness (mm)+4.26 In high school boys the values were: density: 1.0723, body fat: 10.4%, and mean skinfold thickness: 7.89 mm. Coefficients of correlation between mean skinfold thickness and density were r=-0.868 and r=0.855 with % fat. Thus, Body density=$-0.00365{\times}Mean$ skinfold thickness (mm)+1.1008, and %Fat=$1.326{\times}Mean$ skinfold thickness (mm)-0.064, were obtained. Although skinfold thicknesses at 4 sites showed a continuous increase in absolute value as age increased, relative growth of skinfold at specific site differed. On arm the growth of skinfold showed a decrease and on waist it showed an increase as compared to the mean thickness.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.4
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• pp.246-250
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• 2014

This study was carried out to investigate the anion-distribution of the famous valleys in Jeollanam-do. Sampling sites were the valley region of Eochi, Surak, Daeheungsa and Namchang. The maximum values of the anion level were 11,190~178,100 ea/mL at each site and the highest value was measured at the Surak. The mean values showed 14,060 ea/mL in Surak, 8,590 in Eochi, 8,420 in Daeheungsa and 7,020 in Namchang. For a day, the highest Concentration showed in the 5:00 a.m to 7:00 a.m and the lowest values showed in the 12:00 p.m to 14:00 p.m. According to the distance from the source, the anion tended to disappear within 7 m in Namchang and Daeheungsa. But, it influenced by 50 m in Eochi and Surak. Correlation coefficient was -0.54 with wind speed, 0.34 with humidity about the formation of anion. There was no significant correlation with wind speed in the island and longevity village where we had studied in 2009 and 2011. But there was similar correlation with humidity in the island region. Therefore, we can say that wellbeing life is walking around the valley early in the morning with no wind.

• Journal of Soil and Groundwater Environment
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• v.7 no.2
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• pp.3-11
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• 2002

The objective of this study was to survey the oil contamination around the Mountain Baegun at Uiwang city to obtain the preliminary data for bioremediation. For measuring the oil concentrations and physical properties from soil, we analyzed BTEX. TPH and pH, organic content, water content, pormeability coefficient, gravity, porosity and used the purge & trap method for analyzing BTEX. Using the Accelerated Solvent Extractor, we pretreated the samples and then analyzed TPH using GC-FID as soon as possible. From the analysis results, maximum concentration of TPH was 24.773mg/kg and BTEX was 101.7mg/kg. The results of TPH at the Mountain Baegun were higher than the enforcement standard of soil contamination(Korea) and the BTEX concentrations were also higher than the advisory standard of soil contamination(Korea). From these results, the Mountain Baegun may requires to remedy the oil-contaminated soil. In addition, we performed the field bioremediation test for five weeks at the Mountain Baegun using the microbial additives that were developed by our laboratory. From the results of the field test, we could find the about 95% of the oil was removed from the contaminated soil in five weeks. So we consider that it is the one of the useful solutions to remedy the oil-polluted site.

• Korean Journal of Weed Science
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• v.2 no.2
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• pp.129-140
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• 1982

Herbicides were classified by two-dimensional ordination analysis based on the weed flora which was not controlled by application of a particular herbicide. The number of herbicide group was varied depending upon the weed community type and the experiment site. The technique of the two-dimensional ordination analysis gave more comprehensive informations about selecting of herbicides for increasing the herbicidal efficacy, for increasing the weed spectrum and for reducing the herbicide cost by mixing of herbicides. The two-dimensional ordination analysis could be used not only herbicide classification and selecting effective herbicide or herbicide combination but also can be used for the evaluation of systematic application of herbicides.

• Journal of Wetlands Research
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• v.19 no.4
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• pp.515-522
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• 2017

This study investigated the runoff characteristics containing NPS pollutants in urban areas and estimated the optimal number of storm events to be monitored. 13 residential areas, 8 commercial areas, 9 transportation areas and 11 industrial areas were selected to be monitored located in urban areas. Monitoring was performed from 2008 to 2016 with a total of 632 rainfall events. As a result, it was found that commercial area needs priority NPS management compared to other landuses because the commercial area has high runoff coefficient and NPS pollutant EMC compared with other landuses. The annual monitoring frequency for each landuse was estimated to be 11 to 14 times for industrial area, 12 to 14 times for transportation area, 11 to 13 times for commercial area and 22 to 25 times for residential area. Even with the use of accumulated monitoring data for several years, there is still high probability of uncertainty due to high error in some pollutant items, and it is necessary to establish monitoring know-how and data accumulation to reduce errors by continuous monitoring.

• Korean Journal of Materials Research
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• v.8 no.7
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• pp.659-663
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• 1998

The effect of Bi-substitution in $BaO.(Nd_{1-x}Bi_x)_2O_3.4TiO_2$ ceramic was studied on the formation of crystal phases, microstructure, and microwave dielectric properties. $BaO.(Nd_{1-x}Bi_x)_2O_3.4TiO_2$, solid solution (0$\leq$x$\leq$0.2) were formed by Bi-substitution into the Nd site of $BaO.(Nd_{1-x}Bi_x)_2O_3.4TiO_2$ ceramics. Average grain size increased with Bi-substitution. Dielectric constant(${\varepsilon}_r$) increased from 84 to U8, and the temperature coefficient of resonant frequency(${\tau}_f$) decreased from 44 ppm/$^{\circ}C$ to -30 ppm/$^{\circ}C$ when Bi contents increased up to x=0.2 in $BaO.(Nd_{1-x}Bi_x)_2O_3.4TiO_2$ solid solutions. $BaO.(Nd_{1-x}Bi_x)_2O_3.4TiO_2$ solid solutions with x=0.04~0.08 showed the most superior microwave dielectric properties, those are ${\varepsilon}_r$= 89-92, Q . f = 5855~6091 GHz, and (${\tau}_f$)= -7.5-7.5 ppm/$^{\circ}C$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.4
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• pp.175-180
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• 2011

The doping effect of Cu in the Sr-doped lanthan manganites (LSM) has been investigated in terms of structural analysis and thermal expansion coefficient (TEC). The $La_{0.8}Sr_{0.2}Mn_{1-x}Cu_xO_3$ ($0{\leq}x{\leq}0.3$) were prepared by solid state reaction method and their crystal structure and TEC were measured. A decrease in the lattice parameters and the TEC were observed with increase eu content, whereas they were decreased for x = 0.3. For $0{\leq}x{\leq}0.2$, the decrease of the lattice parameter and the TEC with increase Cu content were attributed to the reduction of ionic radius of Cu ions due to the presence of $Cu^{3+}$ ions. For x = 0.3, however, the increase was originated from the formation of oxygen vacancies due 10 the presence of $Cu^{2+}$ and $Mn^{4+}$.

• Journal of dental hygiene science
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• v.5 no.4
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• pp.199-204
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• 2005

Background : Oral leukoplakia(OL) and lichen planus(LP) are common soft tissue lesions characterized by white plaque or striae with erosion. The clinical characteristics of these diseases are similar but the cause and clinical course of them are very different. I compared OL with LP by analysizing clinical and histopathological characteristics and follow up study. Patients and methods : The clinical analysis of 200 patients with OL and LP was performed by review of dental and medical charts. And H/E slides were examined under the light microscope. we examined H/E slides by the light microscope. The follow up study of patients was performed. Statistical analysis was done using the SPSS/PC WINDOWS (version 13.0). Results : The age distribution of OL was in the range of 13-75 years old being most prevalent in the 5th decade and there was a tendency of male prevalent. The age distribution of LP was in the range of 20-79 years old being most prevalent in the 4th decade and there was a tendency of female prevalent. The most common site of involvement was the buccal mucosa in both diseases. The most common clinical features of OL and LP were white plaque type and white lesion with striae, respectively. In case of LP, the most common clinical sign was tenderness to palpation. Fifteen cases of OL and eight cases of LP showed epithelial dysplasia. Twelve cases of OL recurred after surgery of oral squamous cell carcinoma and 2 cases of LP were transformed into oral squamous carcinoma. Conclusion : There was statistically significant difference in age, sex, clinical signs of patients, frequency of epithelial dysplasia between OL and LP. The Pearson coefficient correlation efficient was 0.51(p < 0.05). The knowledge of the difference between OL and LP can help understand these diseases.

• Journal of the Korean earth science society
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• v.33 no.1
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• pp.39-48
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• 2012

In this study, a statistical estimation of probable precipitation and an analysis of its return period in Busan were performed using long-term precipitation data (1973-2007) collected from the Busan Regional Meteorological Administration. These analyses were based on the method of probability weighted moments for parameter estimation, the goodness-of-fit test of chi-square ($x^2$) and the probability plot correlation coefficient (PPCC), and the generalized logistics (GLO) for optimum probability distribution. Moreover, the spatial distributions with the determination of probable precipitation were also investigated using precipitation data observed at 15 Automatic Weather Stations (AWS) in the target area. The return periods for the probable precipitation of 245.2 and 280.6 mm/6 hr with GLO distributions in Busan were estimated to be about 100 and 200 years, respectively. In addition, the high probable precipitation for 1-, 3-, 6-, and 12-hour durations was mostly distributed around Dongrae-gu site, all coastal sites in Busan, Busanjin and Yangsan sites, and the southeastern coastal and Ungsang sites, respectively.