• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.8
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• pp.48-56
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• 2000

Effects of the correlated random fluctuation in each grating half-period have been studied by an effective index transfer matrix method in quarter wavelength shifted DFB lasers. As the correlation coefficient changes from 0 to -1, single mode stability and wavelength accuracy are less degraded by the reduced error in the grating period. This fact shows that holographic grating fabrication is better than electron-beam lithography in discrete device fabrication provided that the magnitude of the random fluctuation is the same.

• The Journal of Fisheries Business Administration
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• v.46 no.1
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• pp.93-107
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• 2015

This study aims to analyze causalities among Hairtail prices by distribution channel using a vector autoregressive model. This study applies unit-root test for stability of data, uses Granger causality test to know interaction among Hairtail Prices by distribution channel, and employes the vector autoregressive model to estimate statistical impacts among t-2 period variables used in model. Analyzing results of this study are as follows. First, ADF, PP, and KPSS tests show that the change rate of Hairtail price by distribution channel differentiated by logarithm is stable. Second, a Granger causality test presents that the producer price of Hairtail leads the wholesale price and then the wholesale price leads the consumer price. Third, the vector autoregressive model suggests that the change rate of Hairtail producer price of t-2 period variables statistically, significantly impacts change rates of own, wholesale, and consumer prices at current period. Fourth, the impulse response analysis indicates that impulse responses of the structural shocks with a respectively distribution channel of the Hairtail prices are relatively more powerful in own distribution channel than in other distribution channels. Fifth, a forecast error variance decomposition of the Hairtail prices points out that the own price has relatively more powerful influence than other prices.

• The Korean Journal of Food And Nutrition
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• v.12 no.1
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• pp.85-90
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• 1999

The characcteristics of anthocyanin pigments from crab apple (Malus prunifolia Wild. Borkh. "red fruit") by ethanol extract were investigated at various condition of light temperature sugar, organic acid me-tal ion and pH. The pigments were stable(over the 60%) on the light irradiation throughout 20 days sto-rage period at room temperature and in the pesenc of Al-foil red blue green and yellow cover were rage period at room temperature and in the pesence of Al-foil red blue green and yellow cover were very stable. The pigments also showed high thermal stbility(over the 67% at 115$^{\circ}C$ 10min) at pH2.5 respectively. The pigments with added organic acid greatly increased thickness of red color. The pig-ments with added metal ions at pH 2.5 such as Na+ K+, Mg2+ Ca2+ and Mn2+ were stable throughout 20 days storage period at $25^{\circ}C$. But Cu2+ addition showed the rapidly degradation of the pigments and Al3+ addition induced the color conversion from red to redish violet. The thickness of the red color of anthocyanin pigments increased increased as the pH decreased. These results indicated that crab apple antho-cyanin pigments might be potental source of natural food colorant. colorant.

• New & Renewable Energy
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• v.9 no.3
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• pp.36-42
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• 2013

To secure raw materials of biodiesel production, the possibility of camellia (C. japonica L.) and tea (C. sinensis L.) seed oil was studied to produce biodiesel. In this research, crude oil contents and fatty acid compositions of seeds were analyzed by Solxlet and Gas chromatography (GC). The oil contents in the seeds of camellia were 69.8%~73.8%, and tea were 26.3%~29.4%. Among the fatty acids of camellia and tea oil, oleic acid was dominant. The unsaturated fatty acids accounted for 88.4% and 80.2% of the whole fatty acids of camellia and tea seed oil. Total seed oil content and fatty acid composition of tea seed were influenced by collecting date. Across maturation period, oil content of tea seed averaged 18.3% on $6^{th}$ September increasing to 27.9% by $11^{th}$ October. For largest seed yield and oil content, the optimum time to harvest tea is in middle october, and camellia is late september and thereafter. The extraction efficiency of oil from seeds by extraction methods was determined. Biodiesel were synthesized in 92.1~92.8% yields from camellia and tea oils by transesterification. The biodiesel was characterized by its physical and fuel properties including oxidation stability, iodine value and cold filter plugging point (CFPP). Oxidation stability of camellia was 8.6~8.8 hours and tea was 2.9~3.6 at $110^{\circ}C$. Camellia oil had considerably better oxidation stability and CFPP than tea oil.

• Korean journal of food and cookery science
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• v.18 no.4
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• pp.407-412
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• 2002

The purpose of this study was to investigate the oxidative stability of green tea-added mayonnaise during storage at 5, 15 and 25$\^{C}$. Mayonnaise was prepared with salad oil, egg yolk, sugar, salt and vinegar, and added with 0.1, 0.3 and 0.5% of green tea powder for experiment. Peroxide values (POV) of each mayonnaise were compared during storage for 13 weeks. POVs of control mayonnaise stored at 5, 15 and 25$\^{C}$ for 13 weeks were 28.0, 63.5 and 144.4 meq/kg, respectively. Oxidative stability of green tea-added mayonnaise was increased with increasing concentration of green tea in mayonnaise, but it was decreased with increasing storage temperature. The addition of green tea at 0.5% extended the induction period of mayonnaise significantly (p<0.05) at each temperature. Relative antioxidant effect (RAE) of mayonnaise containing 0.1% of green tea were 226%, 188% and 143% during storage at 5, 15 and 25$\^{C}$, respectively, and it was increased with increasing green tea concentration in mayonnaise. The results suggested that the use of green tea is valuable to inhibit the oxidation of mayonnaise as a natural antioxidant.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.2
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• pp.131-136
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• 1995

An attempt was made to elucidate the stability of serum metabolites and enzyme activities in blood samples taken from rockfish(Sebastes schlegeli), Israeli carp(Cyprinus carpio) and rainbow trout Oncorhynchus mykiss) under different storing conditions. The concentrations of total protein(TP), albumin(ALB), triglyceride(TG), cholesterol(CHOL) glucose(GLC), phosphorus(P) and sodium(Na), and the activities of alanine aminotransferase(ALT) and aspartate aminotransferase(AST) in serum were investigated for 16 days at $15^{\circ}C$(room temp.) and $4^{\circ}C$ (refrigerative) condition, or frozen at $-20^{\circ}C$ for period of 30 days. Though there was a little difference between fish species, the concentrations of TP, ALB, GLC, P, Na in serum were stable at all storing temperatures, while those of TG, CHOL, ALT and AST were not stable, particularly even at the normal temperature. In general, serum components were more stable at refrigerative and frozen conditions than at room temp. storing. However, it was noticeable that the stability of CHOL in rockfish serum was found to be more unstable at $-20^{\circ}C$ than kept at $15^{\circ}C$ or$4^{\circ}C$.

• Current Research on Agriculture and Life Sciences
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• v.28
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• pp.9-15
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• 2010

Extraction Efficiency of colorants from sorghum and its storage stability were examined according to the various extracting and storage conditions in this study. The obtained results were as follows ; The absorbance values of extracted colorants were increased with increasing extract time and temperature. The extraction at pH 4 extract was most efficient among the various pH conditions. In the juice extractor system, the amount of extracted colorant was more in distilled water pre-treatment than pH 5, but it was more in pH 5 in the long time pre-treatment above 20 hour. The color of extract solutions changed through variation of the pH. Its color changed from light yellow to heavy yellow finally red ton by pH increasing. The Methionine addition gave an effect on the storage stability of colorant solution and then had better storage stability. And so it delayed the color change up to storge period 18th day and the stabilizing effect was revealed in order of Methionine 10mmol-addition>20mmol-addtion>non-addtion.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.6
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• pp.529-537
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• 2017

Membrane filtration process is an advanced water treatment technology that has excellently removes turbidity and microorganisms. However, it is known that it has problems such as low economic efficiency and the operating stability. Therefore, this study was to evaluate on the economical feasibility and operational stability comparison of membrane and sand filtration process in Im-sil drinking water treatment plant. For the economic analysis of each process, the electricity cost and chemical consumption were compared. In the case of electric power consumption, electricity cost is $68.67KRW/m^3$ for sand filtration and $79.98KRW/m^3$ for membrane filtration, respectively. Therefore, membrane filtration process was about 16% higher than sand filtration process of electricity cost. While, the coagulant usage in the membrane filtration process was 43% lower than the sand filtration process. Thus, comparing the operation costs of the two processes, there is no significant difference in the operating cost of the membrane filtration process and the sand filtration process as $85.94KRW/m^3$ and $79.71KRW/m^3$ respectively (the sum of electricity and chemical cost). As a result of operating the membrane filtration process for 3 years including the winter season and the high turbidity period, the filtrated water turbidity was stable to less than 0.025 NTU irrespective of changes in the turbidity of raw water. And the CIP(Clean In Place) cycle turned out to be more than 1 year. Based on the results of this study, the membrane filtration process showed high performance of water quality, and it was also determined to have the economics and operation stability.

• Journal of the Korean GEO-environmental Society
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• v.16 no.4
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• pp.23-32
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• 2015

This paper addresses the effects of extreme rainfall on the stability of cut slopes in Yen Bai city, Northern Viet Nam. In this area, natural slopes are excavated to create places for infrastructures and buildings. Cut slopes are usually made without proper site investigations; the design is mostly based on experience. In recent years, many slope failures have occurred along these cuts especially in rainy seasons, resulting in properties damaged and loss of lives. To explain the reason that slope failure often happens during rainy seasons, this research analyzed the influence of extreme rainfalls, initial ground conditions, and soil permeability on the changes of pore water pressure within the typical slope, thereafter determining the impact of these changes on the slope stability factor of safety. The extreme rainfalls were selected based on all of the rainfalls triggering landslide events that have occurred over the period from 1960 to 2009. The factor of safety (FS) was calculated using Bishop's simplified method. The results show that when the maximum infiltration capacity of the slope top soil is less than the rainfall intensity, slope failures may occur 14 hours after the rain starts. And when this happens, the rainfall duration is the deciding factor that affects the slope FS values. In short, cut slopes in Yen Bai may be stable in normal conditions after the excavation, but under the influence of tropical rain storms, their stability is always questionable.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.1
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• pp.1-15
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• 2008

Recently, because of the various factors by uncertainty of underground, the risks in tunnelling have been occurred increasingly. Therefore, it is very important to estimate and control the risks considering geotechnical conditions for tunnel stability and environmental problems by tunnel construction. In this study, the risk analysis for tunnel stability was carried out by classifying the risk factors such as ground support capacity, ground settlement, the inflow of groundwater into the tunnel and the damage by the earthquake. Also, the risk assessment for the environmental problems was performed by calculating the vibration and noise by blasting and the drawdown of the groundwater level caused by tunnel construction. Each risk factor was evaluated quantitatively based on the probabilistic and statistic technique, then it was analyzed the distribution characteristic along overall tunnel site. Finally, it was evaluated that how much each risk factor influences on the construction cost with a period for tunnel construction, so it is possible to perform reasonable tunnel design which was capable of minimizing the risks in the tunnel construction.