• Journal of the Korean Institute of Gas
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• v.2 no.3
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• pp.37-48
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• 1998

A cryogenic liquid stored in the closed cryogenic tank has been studied at various liquid levels. The change of pressure, temperature, and liquid-vapor ratio in the tank depended on the liquid levels. The various phenomena were shown at different liquid levels as follows: (1) liquid level was increased with condensation of vapor: (2) liquid was vaporized in spite of liquid level going up for a certain initial period and then condensation of vapor occurred at higher pressure; (3) liquid was vaporized without liquid level change; (4) liquid was vaporized with liquid level decreasing. If the tank is full with cryogenic liquid, it is extremely dangerous because of soaring the pressure. Therefore the tank must be filled with $90\%$ liquid according to the safety rules. If the tank was filled with $0\%$ ullage, the pressure increment as high as 80bar during first 5 days. With $90\%$ liquid level, however, the pressure was increased as low as 1.5bar in the same period. No matter what the liquid level is, it is very dangerous if the tank is locked-up with filled cryogenic liquid for a long time.

• Journal of agriculture & life science
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• v.45 no.2
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• pp.115-123
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• 2011

Seasoning gochujang sauces were prepared with 0, 10, 20 and 30% concentrated heating chopped garlic (garlic base) and analyzed. These seasoning gochujang storage for 40 days at $37{\pm}1^{\circ}C$ and examined for changes in their physicochemical properties. Hunter color L and b-value of seasoning gochujang were decreased slowly till 20 days of storage then increased afterward. The highest pH of the seasoning gochujang was pH 5.22 in the 30% garlic base added group. The titratable acidity increase significantly till 40 days of storage. As the adding ratio of garlic base increased, reducing sugar content was decreased. The amino-nitrogen content was continually decreased during aging up to 40 days. ABTs radical scavenging activity was increased as garlic base addition level was increased. The activity was decreased with passing by storage period, and below 50% at 40 days storage.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.6
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• pp.699-709
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• 2017

We measured the grain size, total organic carbon (TOC), total nitrogen (TN), and heavy metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, and Zn) in order to understand the spatial distribution and pollution level of organic matter and metals in surface sediment around Goseong Bay, a shellfish farming area, Korea. The surface sediments were composed of finer sediments such as mud and clay. The concentration of TOC, TN, and heavy metals were much higher in the innermost bay than in the mouth and outside of bay. The spatial distribution of organic matter and heavy metals and C/N ratio (5-10) in sediment showed that the organic matter and heavy metals in sediment of the study region were significantly influenced by oceanic origin organic matter and anthropogenic sources, respectively. Based on the results of four assessment techniques (sediment quality guideline, geoaccumulation index, pollution load index, ecological risk index), the sediments around the Goseong Bay were a little polluted for heavy metals and the high metal concentrations in the northern region of bay could adverse impact on benthic organisms in sediment. Thus, the systematic management plan for the improvement of water and sediment environment and the concentrated monitoring of pollutants for sustainable aquaculture and seafood safety around Goseong Bay are necessary in the future.

• Food Science and Preservation
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• v.18 no.3
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• pp.341-348
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• 2011

The nutritional components and antioxidative activities of jujube fruit and leaf were investigated and analyzed to provide basic data for functional food materialization and processing. The nitrogen-free extract contents of the fruit and leaf were 71.92% and 41.51%, respectively. The mineral components of the fruit and leaf were rich in Ca (72.14 and 3,252.09 mg/100 g), K (899.82 and 1,708.12 mg/100 g), and P (172.11 and 286.28 mg/100 g), respectively. The major free sugars of the fruit were glucose (13.01 %) and fructose (7.35%); and of the leaf, sucrose (3.94%) and fructose (0.75%). The ascorbic acid contents were higher in fruit (135.73 mg/100 g) than in the leaf (100.43 mg/100 g). The analysis of the component amino acid showed a relatively high ratio of glutamic acid, aspartic acid, proline, and essential amino acids of leucine, but a low methionine and cystine content. The ABTS and FRAP assays indicated that the butanol fraction of the leaf was a more potent radical scavenger and reducing agent than the other five solvent fractions. The butanol fraction of the leaf also presented inhibitory effects against lipid peroxidation in a dose-dependent manner. Therefore, this study verified that the butanol fraction of the leaf has strong antioxidative activities that are correlated with its high level of phenolics, particularly rutin and quercitrin. These phenolics of jujube leaf can be utilized as effective and safe functional food substances, i.e., natural antioxidants.

• Food Science and Preservation
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• v.18 no.6
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• pp.859-868
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• 2011

This study was conducted to determine the appropriate mixing ratio of Koji and rice Doenjang. Brown rice Doenjang (BR) was prepared with three different ratios of cooked soybean to brown rice Koji [1.5:1 (BR-1); 2:1 (BR-2); and 3:1 (BR-3)], and polished-rice Doenjang (PR) was prepared with cooked soybean and polished-rice Koji (2:1). The components related to the quality of Doenjang were analyzed during 60-day aging. No significant differences were found in the moisture and salt contents between the brown rice Doenjang and the polished-rice Doenjang. The pH, titratable acidity, and bacteria cells increased at 20-30 days aging time, and decreased thereafter. The reducing-sugar and ethyl alcohol contents, on the other hand, increased at 10-20 days previously. These analytical values of the physicochemical and microbiological characteristics increased with the increase in the percentage of koji in each Doenjang. The amino-nitrogen and free-amino-acid contents showed the highest levels in BR-1: 887.6 and $4047.0{\pm}1.5$ mg%, respectively. The ${\gamma}$-aminobutyric-acid (GABA) contents slightly increased with increasing aging time. In the color of Doenjang, the lightness and yellowness increased along with the aging time, but the redness decreased as the aging time increased. These results showed that BR-1 processed the fermentation the fastest compared with the others. Moreover, the reducing-sugar, ethanol, and free-amino-acid contents as palatable components increased rapidly until 30 days aging time.

• Journal of Soil and Groundwater Environment
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• v.19 no.4
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• pp.62-69
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• 2014

In the results of monitoring nitrate concentration in more than 8,000 groundwater wells around agro-livestock, the average and maximum nitrate concentration was 9.4 mg/L and 101.2 mg/L, respectively. Since about 31% of the monitoring wells was exceed the quality standard for drinking water, nitrate control such as remediation or source regulation is required to conserve safe-groundwater in South Korea. Typical nitrate-treatment technologies include ion exchange, reverse osmosis, and biological denitrification. Among the treatment methods, biological denitrification by indigenous microorganism has environmental and economic advantages for the complete elimination of nitrate because of lower operating costs compared to other methods. Major mechanism of the process is microbial reduction of nitrate to nitrite and nitrogen gas. Three functional genes (nosZ, nirK, nirS) that encode for the enzyme involved in the pathway. In this work, we tried to develop simple process to determine possibility of natural denitrification reaction by monitoring the functional gene. For the work, the functional genes in nitrate-contaminated groundwater were monitored by using PCR with specific target primers. In the result, functional genes (nosZ and nirK) encoding denitrification enzymes were detected in the groundwater samples. This method can help to determine the possibility of natural-nitrate degradation in target groundwater wells without multiplex experimental process. In addition, for field-remediation application we selected nitrate-contaminated site where 200~600 mg/L of nitrate is continuously detected. To determine the possibility of nitrate-degradation by stimulated-natural attenuation, groundwater was sampled in two different wells of the site and nitrate concentration of the samples was 300 mg/L and 616 mg/L, respectively. Fumarate for different C/N ratio was added into microcosm bottles containing the groundwater to examine denitrification rate depending on carbon concentration. In the result, once 1.5 times more than amount of fumarate stoichiometry required was added, the 616 mg/L of nitrate and 300 mg/L of nitrate were completely degraded in 8 days and 30 days. The nitrite, byproduct of denitrification process, was also completely degraded during the experimental period.

• Korean Journal of Soil Science and Fertilizer
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• v.4 no.1
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• pp.1-11
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• 1971

1. Rice plant grown with silica had more elect leaves and heading was one week earlier with silica than without silica grown in both water culture and Akiochi soil. 2. Silica content of rice plant was apparently increased by silica application and the increase insilica was more increased by bassal application of silica than top dressing. The content of other eements in plant decreased with silica application and the trend was most noticeable in iron. 3. Rice plant low in silica were more susceptible to reaf blast, Helminthosporium, mites and smaller brown plant hopper. 4. There was no significant effect of silica on increasing the dry matter production of rice plant grown on water culture, but silica remarkerbly increased the dry matter production of rice plant grown on Akiochi soil. The increasing effect of silica on rice grown on Akiochi fields was more noticeable than that of grown on Pots. 5. In rice plant grown on Akiochi soil, number of spikelets and percentage of ripened grains were increased by application of silica. The silica effects can be increased by application of well balanced nitrogen and potassium ratio. 6. From these results, it can be concluded that silica seems to have no direct effect on rice growth, but application of silica to Akiochi soil associated with low silica supply may be critical for healthy growth of rice plant, and silica directly related to rice agronomy.

• Clean Technology
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• v.27 no.3
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• pp.223-231
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• 2021

In order to address many issues associated with large volume changes of silicon, which has very low electrical conductivity but offers about 10 times higher theoretical capacity than graphite (Gr), a silicon nanoparticles/hollow carbon (SiNP/HC) composite having bimodal-mesopores was prepared using silica nanoparticles as a template. A control SiNP/C composite without a hollow structure was also prepared for comparison. The physico-chemical and electrochemical properties of SiNP/HC were analyzed by X-ray diffractometry, X-ray photoelectron spectroscopy, nitrogen adsorption/desorption measurements for surface area and pore size distribution, scanning electron microscopy, transmission electron microscopy, galvanostatic cycling, and cyclic voltammetry tests to compare them with those of the SiNP/C composite. The SiNP/HC composite showed significantly better cycle life and efficiency than the SiNP/C, with minimal increase in electrode thickness after long cycles. A hybrid composite, SiNP/HC@Gr, prepared by physical mixing of the SiNP/HC and Gr at a 50:50 weight ratio, exhibited even better cycle life and efficiency than the SiNP/HC at low capacity. Thus, silicon/carbon composites designed to have hollow spaces capable of accommodating volume expansion were found to be highly effective for long cycle life of silicon-based composites. However, further study is required to improve the low initial coulombic efficiency of SiNP/HC and SiNP/HC@Gr, which is possibly because of their high surface area causing excessive electrolyte decomposition for the formation of solid-electrolyte-interface layers.

• Animal Bioscience
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• v.34 no.10
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• pp.1616-1622
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• 2021

Objective: Bioactive compounds in ruminant products are related to functional compounds in their diets. Therefore, this study aimed to explore the effect of forage sources, Italian ryegrass (IR) silage vs corn silage (CS) in the total mixed ration (TMR), on milk production, milk composition, and phytanic acid content in milk, as well as on the extent of conversion of dietary phytol to milk phytanic acid. Methods: Phytanic acid content in milk was investigated for cows fed a TMR containing either IR silage or CS using 17 cows over three periods of 21 days each. In periods 1 and 3, cows were fed CS-based TMR (30% CS), while in period 2, cows were fed IR silage-based TMR (20% IR silage and10% CS). Results: The results showed that there were no differences in fat, protein, lactose, solids-not-fat, somatic cell count, and fatty acid composition of milk among the three experimental periods. There were no differences in the plasma concentration of glucose, triglycerides, total cholesterol, and nonesterified fatty acids among the three experimental periods, while the blood urea nitrogen was higher (p<0.05) in period 2. The milk phytanic acid content was higher (p<0.05) in period 2 (13.9 mg/kg) compared with periods 1 (9.30 mg/kg) and 3 (8.80 mg/kg). Also, the phytanic acid content in the feces was higher (p<0.05) in period 2 (1.65 mg/kg dry matter [DM]) compared with period 1 (1.15 mg/kg DM), and 3 (1.17 mg/kg DM). Although the phytol contents in feces did not differ among the three feeding periods, the conversion ratio from dietary phytol to milk phytanic acid was estimated to be only 2.6%. Conclusion: Phytanic acid content in cow's milk increases with increasing phytol content in diets. However, phytol might not be completely metabolized in the rumen and phytanic acid, in turn, might not be completely recovered into cow's milk. The change of phytanic acid content in milk may be positively correlated with the change of phytol in the diet within a short time.

• The Korean Journal of Food And Nutrition
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• v.32 no.2
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• pp.114-121
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• 2019

This study evaluates the quality properties of soy-paste soybean cultivar for fermented soybean products. The six soybean varieties that include Jinpung, Saedanbaek, Daepung 2, Pyeongwon, Cheonga and Saeolkong were used in the experiment. The range of water uptake ratio, hardness after soaking and hardness after steaming were 117.00~131.33%, 1.65~3.30 kg and 0.05~0.14 kg, respectively. The physicochemical analysis indicated the following: Moisture content, 63.27~68.72%; pH, 6.43~6.60; total acidity, 0.27~0.45%. Color values for L value (lightness), a value (redness), and b value (yellowness) ranged from 39.07~67.92, 7.64~11.79, and 7.48~20.67, respectively. The amylase and protease activities of the Saedanbaek samples were the highest among all cultivars. The amount of viscous substance in the fermented soybean products by cultivars ranged from 5.93 to 8.37%, and Saedanbaek was the highest. The total viable cells counts for soybean fermented products were 9.11~9.42 log CFU/g. The amino-type nitrogen contents of all samples were in the range of 401.07 to 524.47 mg% and Saedanbaek cultivars showed the highest content (524.47 mg%). Based on the results, Saedanbaek will be suitable as a soy-paste soybean cultivar and the quality standards for the fermentation process of the fermented soybean products.