• ALGAE
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• v.17 no.2
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• pp.105-115
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• 2002

Influences of vrious environmental factors on the eutrophication of Nakdong River were analyzed statistically using water samples collected from 1 January, 1999, to 30 September, 2001 at Namji area. The relationships between the concentration of chlorophyll α (eutrophication index) and environmental factors and were analyzed to develop a statistical model which can predict the status of eutrophication. The concentation of chlorophyll α ranged from 66.2 mg · $m^{-3}$ to 70.8 mg · $m^{-3}$ during dry winter season and the average concentration during this study period was 35.5 mg · $m^{-3}$ Namji area of Nakdong River was in the hypereutrohic stage in terms of water quality. Stephanodiscus sp. and Aulacoseria granulata var. angustissima were dominant species during the witnter to spring time and summer to autumn period, respectively. Based on the correlation analysis and the analysis of variance between chlorophyll α concentration and environmental factors, significantly high positive relationships were found in the order of BOD> pH> COD > KMnO₄ consumption > DO > conductivity > alkalinity. In contrast to these factors, significantly negrative relationships were found as in the order of $PO₄^{3-}-P$ >water level>the rate of Namgang-dam discharge > NH₃-N> the rate of Andong-dam discharge> the rate of Hapchoen-dam discharge. Based on the factors analysis of environmental factors on the concentration of chlorophyll α, we obtained five factors as follows. The first factor included water level, pH, turbiditiy, conductivity, alkalinity and the rate of Namgang-dam discharge. The second factor included water temperature DO, NH₄+-N, NO₃- -N. The third factor included KMnO₄ consumption COD and BOD. The fourth factor included the rate of Andong-dam discharge, the rate of Hapcheon-dam discharge, and the rate of Imha-dam discharge. The final factor included T-N T-P and $PO₄^{3-}-P$ > concentration. We derived two statistica models that can predict the occurrence of eutrophication based on the factors by factor analysis, using regression analysis. The first model is the stepwise regression model whose independent variables are the factors produced by factor analysis : chl α (mg · $m^{-3}$ = 42.923+(18.637 factor 3) + (-17.147 factor 1) + (-12.095 factor 5) + (-4.828 factor 4). The second model is the alternative stepwise regression model whose independent variables are the sums of the standardized main component variables:chl α (mg · $m^{-3}$ = 37.295+(7.326 Zfactor 3) + (-2.704 Zfactor 1)+(-2.341 Zfactor 5).

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.6
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• pp.9-16
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• 2000

In order to achieve stiction-free polysilicon surfaces, we have suggested a new class of chemical coating precursors and confirmed their excellent characteristics. The strategy is to adopt dialkyldichlorosilanes (DDS, $R2SiCl_2$) instead of monoalkyltrichlorosilanes (MTS, $RSiCl_3$) such as octadecyltrichlorosilane (OTS) or 1H,1H2H,2H-perfluorodecyltrichlorosilane (FDTS). Dichlorodimethylsilane (DDMS, $(CH_3)2SiCl_2$) in this study is commercially available DDS with two short chains. DDMS in aprotic media spontaneously deposits on the hydrophilic polysilicon surface, which is completely changed to hydrophobic one. When polysilicon surface is exposed to DDMS solution at room temperature, anti-stiction property and hydrophobicity are clearly comparable to FDTS. DDMS is even superior to MTS in reliability and easy handling, which provides high yield. Since interactions among precursor molecules are reduced, conglomeration both in homogeneous solution and on surface can be effectively avoided. Even the cantilevers of 3 mm in length can be protected successfully from the stiction and the final quality of the modified surfaces is much less dependent on temperature. And no difference was found between the processes in ambient environment and in dry box. In addition, DDMS has advantages of remarkably reduced process time and low cost.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.4
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• pp.397-404
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• 1994

This experiment was conducted to determine best harvesting time and observe paeoniflorin and some chemical component concentrations of 4-year-old paeonia radix in Euisung and Milyang varieties. Concentrations of paeoniflorin and some chemical components were investigated at 8 periods from Feb. to Oct. Yield of paeonia radix was investigated in Aug. 19, Sep. 18 and Oct. 17. Paeoniflorin and some chemical components were changed seriously at May as flowering time and stabilized after June. The lowest dry matter ratio was 23% and the maximum shrinkage ratio was 47% in May during all the growing stages. Especially, the difference of paeoniflorin concentrations between Euisung and Milyang was about 2%, and paeoniflorin concentrations in Milyang were higher than in Euisung variety during all the stages. Serious infection of disease in October, stem length, stem number per stock and healthful stem ratio in October were more reduced than in August. Yield of paeonia radix was not different from August to September, but that of October harvest was obviously reduced by root-decay-disease. Reasonable harvesting time in 4-year-old paeonia radix was late August to mid-September. When infected shoot rate by disease were severely high, early harvest was more stable in the yield and quality aspects.

• Food Science of Animal Resources
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• v.35 no.1
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• pp.143-148
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• 2015

Yogurt powder is fermented milk processed in the form of dry yogurt, and has advantages such as stability, storability, convenience, and portability. China and Vietnam are important export target countries because of the increased demand for dairy products. Therefore, we surveyed dairy product standardization in order to establish an export strategy. Lactic acid bacteria counts are unregulated in Korea and Vietnam. In China, lactic acid bacteria counts are regulated at $1{\times}10^6$ colonyforming units (CFU)/mL and detected at $6.24{\pm}0.33\;Log\;CFU/mL$. All three countries have regulated standards for total bacterial counts. In China, total bacterial counts of milk powder are regulated to n=5, c=2, m=50,000, M=200,000 and detected at $6.02{\pm}0.12\;Log\;CFU/mL$, exceeding the acceptable level. Lactic acid bacterial counts appeared to exceed total bacterial counts. Coliform group counts, Staphylococcus aureus, Listeria monocytogenes, and Salmonella species were not detected. Acidity is not regulated in Korea and Vietnam. In China, acidity was regulated to over $70^{\circ}T$ and detected $352.38{\pm}10.24^{\circ}T$. pH is unregulated in all three countries. pH was compared to that of general fermented milk, which is 4.2, and that of the sample was $4.28{\pm}0.01$. Aflatoxin levels are not regulated in Korea and China. In Vietnam, aflatoxin level is regulated at 0.05 ppb. Therefore, all ingredients of the yogurt powder met the safety standards. This data obtained in this study can be used as the basic data in assessing the export quality of yogurt powder.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.1
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• pp.86-93
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• 2004

Sixteen early lactating Nili-Ravi buffaloes, four animals in each group, were used in a Completely Randomized Design to evaluate the effect of varying levels of both ruminally protected fat and urea treated corncobs ensiled with or without corn steep liquor (CSL) on feed intake, digestibility and milk production and its composition. Four experimental diets were formulated. The control (C) diet was balanced to contain 0% fat and 35% urea treated corncobs ensiled with 0% CSL. The low fat (LF), medium fat (MF) and high fat (HF) diets had 45, 55 and 65% urea treated corncobs ensiled with 9% CSL and 2, 4 and 6% ruminally protected fat, respectively. Dry matter, crude protein (CP) and neutral detergent fiber (NDF) intakes by buffaloes remained similar across all treatments. However, DM and NDF as a percent of body weight and digestible DM intakes were higher in HF diet when compared to C, LF and MF diets. Digestible NDF intakes were also significantly higher in HF diet as compared to all other diets. The intakes of ADF and digestible ADF were higher in MF and HF than C and LF diets. The significant variation in digestible DM, ADF and NDF intakes may be attributed to the ammoniation of corncobs along with CSL that caused significant changes in the degradability and digestibility of the diets. Ether extract and digestible EE intakes differed significantly (p<0.05) among all treatments. Intakes of EE were the highest in animals fed HF diet, which was because of added fat. Apparent DM digestibility was the highest in animals C diet and was the lowest in those fed LF diet. Neutral detergent fiber and ADF digestibilities were higher in animals fed diets containing urea treated corncobs ensiled with 9% CSL when compared to those fed diets containing urea treated corncobs ensiled without CSL. Apparent digestibility of CP was noted highest (71.47%) in animals fed HF diet when compared to those fed MF (67.75%), LF (67.04%) and C (65.39%) diets. Milk yield (4% FCM) was the higher in buffaloes fed HF, MF and LF diets than those fed C diet. These results indicated that increasing levels both of fat and urea treated corncobs ensiled with CSL elevated the negative effects of poor quality fibrous feed on milk production by buffaloes.

• Journal of the Korea Institute of Building Construction
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• v.10 no.5
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• pp.95-102
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• 2010

In recent years, the demand for the development of high quality and cost effective materials, as well as the competition to ensure a diverse and sufficient amount of ready-mixed concrete, has been increasing rapidly. In this experiment, concretes made with different admixtures are blended with each other in different combinations and ratios, in order to identify potential problems. The first test was a slump level test, in which all of the concretes met the required numbers, as they also did in the test for air content. Plain organic acid concrete scored the highest in bleeding amount, but organic acid mix in general showed a similar outcome. In the early measurement of compressive strength, plain naphthalene concrete was the strongest. Of the blends, the 5:5 mix of organic acid and naphthalene was the strongest. In the standard measurement, the 5:5 mix of naphthalene and lignin was the strongest. Tensile strength tests revealed similar results. Length change rate proved to be greater in blended concrete than in plain concrete, and dry shrinkage rate was highest in the 7:3 ratio blends. Through SEM photo analysis, it was confirmed that the 7:3 ratio blends contained more micro-voids. In conclusion, with the exception of a specific few combinations, it was found that the blending of different types of concrete is undesirable due to the delayed coagulation time as well as the early decrease in strength.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.37-43
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• 2019

Since 3D printed concrete can be constructed without formwork, it is easy to construct an atypical structure, and the construction time and labor cost can be reduced. However, since the construction is exposed to the outside, shrinkage cracking due to moisture loss inside and outside the concrete occurs. Therefore, in order to improve the durability of the 3D printed concrete, a shrinkage reduction plan of the 3D printed concrete is required. In this study, glycol-based and alcohol-based shrinkage reducing agents were fabricated and evaluated for their performance. The shrinkage reducing agent samples showing excellent performance were selected and applied to 3D printed concrete. As a result, the compressive strength was increased by more than 10% and the shrinkage was reduced by more than 36% when using a shrinkage reducing agent. It is expected that the production of high quality 3D printed concrete will be possible because it is possible to increase the compressive strength and reduce the amount of dry shrinkage by applying a shrinkage reducing agent for 3D printed concrete.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.3
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• pp.341-349
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• 2014

Field emergence of Azuki bean is poor due to hard seed coat as compared to other legumes. In this study, an attempt was made to develop prediction method with regression analysis based on various seed vigor tests in laboratory for field emergence of azuki bean. Azuki bean seeds artificially aged to provide various levels of seed quality were evaluated by the standard germination test (SGT), cold germination test (CT), cool germination test (CGT), complex stressing vigor test (CSVT), tetrazolium(TZ) vigor test and electroconductivity test. The SGT was suitable for predicting the field emergence in the unaged high vigor seeds. The abnormal seedling percentage and shoot length in the CGT were highly correlated with field emergence of moderate vigor seeds artificially aged for 2 days. Electroconductivity, seed viability in the CSVT, and vigor and predicted germinability in the tetrazolium vigor test were also useful for predicting field emergence. Percent of ungerminated seed in the CSVT was correlated with field emergence in the low vigor seeds artificially aged for 4 days. In a stepwise multiple regression analysis, seed viability in the SGT, normal seedling percentage and dry matter weight in the CGT accounted for 86.9% of the predicted value of field emergence in azuki bean.

• Current Research on Agriculture and Life Sciences
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• v.31 no.1
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• pp.56-60
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• 2013

This research was carried out to produce rainbow-colored roses from white cut rose, Rosa hybrida 'Denice', to meet customers' desire of having various colors of roses. The higher temperature of dyeing solution used, the faster coloring time surveyed. In high temperature, the flowering speed of cut flower accelerated and after treating more than 4 hours, the edges of flowers became too dark or dry. In the condition of concentration of dyeing solution, $11g{\cdot}L^{-1}$ dyed faster than $7.5g{\cdot}L^{-1}$, however, no differences between $15g{\cdot}L^{-1}$ and $11g{\cdot}L^{-1}$ have observed. It looked fast coloration at the stage of early blooming, but all three different petal opening stages need similar time to get even coloration from outer to inner petals. For the consideration of commercial value, flowers with 3-4 petals opened are better quality than flowers with less petals opened. It was possible to make rainbow-colored rose by dipping 'Denice' with 3 primary color combination, Hot Pink, True Blue, and Yellow dyes, at the best result conditions of $20^{\circ}C$ solution temperature, 3-4 petals opening stage, 11g/L concentration of dye solution and 3 hours dipping, respectively.

• Journal of the Korea Computer Industry Society
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• v.8 no.2
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• pp.107-112
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• 2007

Laser wave length can have evaporation effect by absorption because outer skin or tissue of focus is consisted of water almost though absorption of water occurs more than 90% almost in formation thickness of very thin floor. Can operate outer skin, steam by floor and correct incision of formation is available. Suture surgical operation is available to vein or lymph system and surgical operation region can dry and see as eye and radish bleeding surgical operation is available. Specially, stability of tube both end output about pulse by weight very, this research can cause various curative effect because can reduce bulk and control easily current wave style of medical laser using electric power conversion device of high frequency way. If introduce ZVS (Zero Voltage Switching) or ZVZCS (Zero Voltage and Zero Current Switching), is more profitable because can reduce switching damage. Because electric power department of proposed medical laser can do stable soft-switching in wide subordinate extent introducing ZVZCS technique by the first help and control department composes microcontroller, output current waveform user have free form make Result that experiment because design and manufacture, brought result that improve of 20% than existing equipment, and will be bought to get into superior result if supplement as systematic late.