• Korean Journal of Environmental Agriculture
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• v.8 no.1
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• pp.55-59
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• 1989

To determine the accurate C/N ratio of compost, biodegradable carbon and nitrogen in compost must be analyzed. In biodegradable nitrogen analyzed by Kjeldahl Method, nitrate and nitrite which are available for microbes can not be detected at all. By means of $F{\"{o}}rster$ Method, nitrate and nitrite can be detected. Therefore, various nitrogens in compost were analyzed by Kjeldahl and $F{\"{o}}rster$ Method to investigate the seasonal changes of various C/N ratios of compost. C/N ratios in compost analyzed by Kjeldahl and $F{\"{o}}rster$ Method were decreased rapidly within 2 weeks after composting, then were not changed to 6 weeks, and thereafter were decreased slowly with the lapse of composting time. C/N ratios analyzed by Kjeldahl Method were higher than those analyzed by $F{\"{o}}rster$ Method. C/N ratios of total carbon/total nitrogen analyzed by Kjeldahl Method were higher(5 as C/N ratio or 36%) than those of biodegradable carbon/biodegradable nitrogen analyzed by $F{\"{o}}rster$ Method. Highly positive correlations were observed among C/N ratios of total carbon/total nitrogen analyzed by Kjeldahl Method total carbon/total nitrogen analyzed by $F{\"{o}}rster$ Method and biodegradable carbon/biodegradable nitrogen analyzed by $F{\"{o}}rster$ Method one another.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.583-584
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• 2006

This paper presents transistor matching in 70 nm nMOS. To adopt radio frequency(RF) applications, the RF performance, especially the current gain cutoff frequency($f_T$), is examined experimentally through a wafer. It is proved that the RF performance variation of 70 nm nMOS is dependent to the device geometry, the total width(W). The RF performance variation of 70 nm nMOS is inversely proportional to square root of total width(W). Also, decreasing of the number of fingers($N_f$) is helpful to decrease the variation of 70 nm nMOS.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1619-1626
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• 2017

Electronic components that are used in high-level radiation environment require a semiconductor device having a radiation-hardened characteristic. In this paper, we proposed a radiation-hardened I-gate n-MOSFET (n-type Metal Oxide Semiconductors Field Effect Transistors) using a layout modification technique only. The proposed I-gate n-MOSFET structure is modified as an I-shaped gate poly in order to mitigate a radiation-induced leakage current in the standard n-MOSFET structure. For verification of its radiation-hardened characteristic, the M&S (Modeling and Simulation) of the 3D (3-Dimension) structure is performed by TCAD (Technology Computer Aided Design) tool. In addition, we carried out an evaluation test using a $Co^{60}$ gamma-ray source of 10kGy(Si)/h. As a result, we have confirmed the radiation-hardened level up to a total ionizing dose of 20kGy(Si).

• ALGAE
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• v.19 no.1
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• pp.49-57
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• 2004

This study was performed to obtain basic information on the ecology of Zostcra marina and to promote efficient conservation of this species which has been decline in Gamak Bay, Yeosu, Korea. Whater column characteristics and eelgrass morphology at Anpori, Jangsuri and Wonpori were investigated every month from December 1999 to November 2000. The water temperature, salinity and pH at the three sites were 10.0-27.0${\circ}C$,29.4-34.7% and 8.1-8.5, respectively. The water temperature at Anpori tended to be slightly lower than that at the other locations; the salinity at Wonpori from July to November was a little lower than that of the other locations. The concentrations of $NO_2$-N, $NO_3$_N, $NH_4$-N, $PO_4$-P and $Si(OH)_4$-Si at the three sites were 0.9-1.3, 2.0-6.2, 7.8-9.0, 3.0-3.6 and 22.2-30.2 uM, respectively. The concentration of $NO_3$-N at Wonpori from June to November was somewhat lower than that at the other locations; that of NH4-N at Jansuri was somewhat lower than the others. The mean shoot height and leaf width of the Anpori, Jangsuri and Wonpori populations were 80.6 cm and 0.9 mm, 90.0 cm and 1.0 mm, and 95.3 cm and 1.0 mm, respectively. The mean total shoot weight of the Anpori, Jangsuri and Wonpori ones was 24.5,31.0 and 29.7 & respectively. The mean leaf and branch numbers of the Anpori, Jangsuri and Wonpori populations were 16.5 and 2.6, 16.1 and 2.4 and 15.4 and 2.6 individuals, respectively. The correlation coefficients between shoot height and water temperature, leaf width and total shoot weight, leaf number and branch number, and $Si(OH)_4$-Si and $NO_3$-N were 0.726, 0.692, 0.862, and 0.693, respectively. The coefficients between shoot height and $NO_3$-N, total shoot weight and NO_3$-N, water temperature and $Si(OH)_4$-Si, water temperature and salinity, and water temperature and $NO_3$-N were -0.716, -0.536, -0.775, -0.685 and -0.685, respectively. The first four principal components explain 71.1% of the total sample variance. For axis 1, shoot height and water temperature tended to correlate with the population of Jansuri, followed by the Wonpori population, and $Si(OH)_4$-Si and $NO_3$-N tended to correlated strongly with the Anpori population. For axis 2, total weight, leaf width, leaf number and branch number showed a tendency to correlate with the Anpori and Jangsuri populations. For axis 3, the Anpori population tended to be influenced by $NO_2$-N and $PO_4$-P. For axis 4, the Wonpori and Jangsuri populations tended to be affected by salinity. The tendency, however, differed according to season.

• Journal of Korean Society on Water Environment
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• v.24 no.1
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• pp.69-77
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• 2008

This study was conducted to know the characteristics of agricultural non-point source pollutants runoff by rainfall events at the upper catchment of Goseong reservoir in Gonjy city, Chungnam Province. For this study, the monitoring sites of the research catchment were set nineteen during the research period (between June 2005 and October 2006). Average runoff coefficient were observed 0.51 in 2005, 0.71 in 2006, respectively. The correlation coefficient (r) between the rainfall and peak-flow was investigated 0.787. By rainfall events, the water quality of the sites were shown like this : BOD 0.555~9.60 mg/L, T-N 0.01~13.50 mg/L, T-P 0.002~2.952 mg/L, and SS N.D~820.0 mg/L. The strong rainfall intensity was the most important factor of the soil erosion. The gabs of the arithmetic mean concentrations and the flow weighted mean concentrations were observed as the followings : BOD 0.0~29.2%, T-N 0.1~11.4%, T-P 0.4~95.2%, and SS 1.7~57.0% in 2005, and BOD 1.0~11.9%, T-N 0.7~7.3%, T-P 9.9~36.5%, and SS 6.6~36.5% in 2006, respectively. The BOD pollution load was 2,117 kg (36% of the total BOD loading of survey periods) while, T-N was 3,209.0 kg (27.9% of the total T-N loading of survey periods), T-P was 136.4 kg (37.4% of the total T-P loading of survey periods) and SS was 72,733.8 kg (51.8% of the total SS loading of survey periods) in the year 2005. In case of 2006, BOD load was 1,321.7, T-N was 2,845.8, T-P was 42.9, and SS was 16,275.8 kg, respectively.

• Journal of the East Asian Society of Dietary Life
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• v.1 no.1
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• pp.99-111
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• 1991

In each nuruk using today, effect of pH on glucoamylase activity and viable cell count of yeast and bacteria was measured. Common components during fermentation, alcohol, acetaldehyde and acetone, amino acid composition, and total sugars and mineral content were determined in yakju(korean wine) brewed from different ingredients and by different methods. Results are summarized as follows ; 1. The lower the pH, the lower the glucoamylase activity in JK, BK, JK-S BK-S and JN. But the higher the glucoamylase activity ratio in Koji and KN. 2. Yeast and bacteria cell count could not determined in nuruk inoculated of seed. In JK, BK and JN, yeast cell count was 50${\times}$104∼80${\times}$104, bacteria cell count was 5${\times}$106∼24${\times}$106. 3. In yakju during fermentation, pH was higher in RU, total acidity content was higher in ST-N, ST-K, RU and ST-RUPO and alcohol content was lower in RUPO and ST-RUPO. 4. Ethanol and acetaldehyde content were highest in dukyunju. Trace amount of acetone was determined only in ST-K, RUPO and ST-RUPO . n-Propyl alcohol content was higher in ST-K, ST-RUPO and ST-N, iso-butyl alcohol content was higher in L-RUPO, Dukyunju and Songyupju and iso-amyl alcohol content was higher in Songyupju, RU, L-RUPO and Dukyunju. 5. In amino acids composition of each yakju, Pro, Ala and Val content was higher than other amino acids. Total amino acids content was the highest in Dukyunju and second highest in ST-N, NH3 was higher in ST-N, Dukyunju, RUPO than other samples. 6. Total sugars content was the highest in ST-N and second highest in RU. 7. P, K and Mg content were higher in Dukyunju and ST-N than in other samples. In Dukyunju, Ca and P ratio was 0.075 because of low Ca content and high P content.

• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.9-16
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• 2013

BACKGROUND: Eutrophication occurs occasionally in reservoirs around lake in summer and early autumn. Lakeside macrophyte which is one of internal pollutants effects on water quality when it is submerged during rainy season. To improve water quality of water supply source in Boknae reservoir around Juam lake, characteristics of nutrient(N, P) uptake and release by submerged plants were investigated. METHODS AND RESULTS: In order to establish the management plan of submerged plants in Boknae reservoir around Juam lake, water level, rainfall, flooding and non-flooding areas, biomass of dominant plants, contents of nitrogen and phosphorus were investigated during 7 months(August, 2010 through February, 2011). Dominant plants were Miscanthus sacchariflorus(MISSA) and Carex dimorpholepis(CRXDM) in Boknae reservoir. Total plant area of Boknae reservoir in August, 2010 was 987,872 $m^2$. In Boknae reservoir, flooding occurred from August until February caused by rainfall during rainy season. The total amounts of nitrogen and phosphorus uptakes by MISSA were 247 and 22 kg/total reservoir area, respectively. By CRXDM, the total amounts of nitrogen and phosphorus uptakes were 11,340 and 1,231 kg/total reservoir area, respectively. The total amounts of nitrogen and phosphorus residues by MISSA were 34 and 11 kg/total reservoir area, respectively. By CRXDM, the total amounts of nitrogen and phosphorus residues were 491 and 68 kg/total reservoir area, respectively. CONCLUSION(S): Total amounts of nitrogen and phosphorus releases in Boknae reservoir were 12,212 and 1,324 kg/total reservoir area, respectively. The results demonstrate that total nitrogen and total phosphorus in water were strongly influenced by submerged plants. Therefore, management plan for submerged plants during rainy season will be needed to improve water quality of water supply source in Boknae reservoir around Juam lake.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.744-750
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• 2015

The objectives of this study were to investigate soil chemical characteristics for forest rehabilitation and suggest management in abandoned coal mine areas in Boryeong City, Chungcheongnam-do. Total study sites were seven sites, and soil properties analyzed were soil pH, total organic carbon (TOC), total-N, C/N ratio, and available $P_2O_5$ (A.v. P). Average soil pH (range) was 5.9 (4.5~7.0). Three study sites (Samgwang, Shinsung1, and Shimwon1) showed lower soil pH than standard (pH 5.6~7.3) of Korea Industrial Standards (KS) for abandoned coal mine forest rehabilitation. Average contents of TOC, and total-N were 1.5% (0.1~4.7%), and 0.10% (0.03~0.23%), respectively. Five study sites where the collapsed time was less than 10 years (Wangjashingang, Wonpoong, Samgwang, Shinsung1, and Shinsung2) showed lower TOC level than standard of KS (more than 1.2%). Wangjashingang, Wonpoong, Samgwang, and Shinsung1 showed lower level of total-N than standard of KS (more than 0.09%). C/N ratio of six study sites except Shimwon1 was out of proper range (15:1~30:1). Average A.v. P (range) was $20.7mgkg^{-1}$ (4.8~63.1), less than other abandoned coal mine fores rehabilitation areas in Mungyong City, and Hwasun-gun. TOC, total N and A.v. P increased with elapsed time from forest rehabilitation, while other soil properties did not show distinct pattern. Betula platyphylla was planted in Samkwang and Sinsung where soil pH was less than KS standard. Because the growth of Betula platyphylla can be limited in acid soil, it is necessary to neutralize soil pH to proper level with some soil amendment such as lime or shell of oyster. Furthermore, TOC, total-N and A.v. P in early stage of forest rehabilitation showed lower level than proper to vegetation growth. Therefore it needs continuous monitoring of soil characteristics and fertilization for vegetation growth and influx from surrounding forest in early stage of rehabilitation.

• Communications of the Korean Mathematical Society
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• v.28 no.4
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• pp.857-863
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• 2013

In this paper, we prove that the total domination number of a $P_6$-free graph of order $n{\geq}3$ and minimum degree at least one which is not the cycle of length 6 is at most $\frac{n+1}{2}$, and the bound is sharp.

• KSBB Journal
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• v.30 no.6
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• pp.302-306
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• 2015

In this work, the antioxidant activity and total phenolic compound content of 6 fractions of Smallanthus sonchifolius, Agrimonia pilosa, and Lithospermum erythrorhizon extract were investigated. The highest total phenolic compound contents of each plant extracts were obtained from n-butanol ($13.75{\pm}0.21%$) and methylene chloride ($12.89{\pm}1.10%$) fractions (S. sonchifolius), ethyl acetate ($19.69{\pm}1.02%$) and water ($18.72{\pm}0.76%$) fractions (A. pilosa), and n-butanol ($36.26{\pm}1.26%$) and ethyl acetate ($17.66{\pm}0.94%$) fractions (L. erythrorhizon), respectively. As a result of DPPH radical scavenging activity in 10 mg/mL condition, the highest activity were obtained from n-butanol fraction of S. sonchifolius (81.06%), ethyl acetate fraction of A. pilosa (86.32%), and n-butanol fraction of L. erythrorhizon (82.6%), respectively. Also, the highest reducing power was obtained same fractions as well as DPPH adical scavenging activity. Overall, antioxidant activity has relatively closely connected with contents of total phenolic compounds in S. sonchifolius and L. erythrorhizon extracts.