• Applied Biological Chemistry
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• v.23 no.2
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• pp.123-130
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• 1980

Thiamine derivatives of thiamine tetrahydrofurfuryl disulfide (TTFD) and thiamine propyl disulfide (TPD) were obtained in a good yield and purity by use of thiothiamine $(SB_1)$ and also described in details for the preparing sodium tetrahydrofurfuryl thiosulphate (Bunte's salt) with and without KI. The optimum reaction conditions for the preparation of TTFD was set in which the Box-Wilson plan was applied. The reaction conditions are as follows; 1. pH value of aqueous solution of thiol type of $B_1{\cdot}HCl;12.09$ 2. Quantity of Bunte's salt (to $B_1{\cdot}HCl\;20G$); 35.01g 3. Reaction temperature; $15.59^{\circ}C$ Studies on ultraviolet absorption were made at various pH and showed that the absorption maxima are shifted with change of pH. The absorption maxima are at $244{\sim}246nm,\;234{\sim}235nm$ in TTFD, and $245{\sim}246nm,\;233{\sim}235nm$ in TPD. The structure was proved by the infrared spectral evidence. Quantitative determination was studied.

• Horticultural Science & Technology
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• v.17 no.2
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• pp.115-117
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• 1999

Tomato (Lycopersicon esculentum) fruits were grown by the hydroponic cultivation system using perlite and soil cultivation system. The growth, yield, and fruit quality were compared between two growing seasons of spring and summer and two cultivation systems, respectively. In tomato, little difference was observed in growth and yield between two cultivation systems, but plant growth and total yield of fruits were much more in summer than in spring. The contents of glucose and fructose were more in spring-grown fruit than in summer-grown one, and in hydroponically cultivated fruit than in soilcultivated, respectively. The weight loss during room temperature storage was lower in hydroponically cultivated fruit than in soil-cultivated one, and in summer-grown fruit than in spring-grown one, respectively. In terms of color change, the shelf-life of tomato fruit was shorter by one day in summer-grown one fruit than in spring-grown one, and in hydroponcically cultivated one fruit than in soil-cultivated, respectively.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.3
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• pp.409-416
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• 2007

This study investigated changes in the catechin and alkaloid contents of Bosung green tea during different manufacturing processes and storage periods, using HPLC and UV-VIS spectrophotometer analysis. For changes in the catechin and alkaloid contents by roasting technique, we found that EGCG, CG and GCG decreased just slightly by processes performed before roasting, rather than after roasting. In addition, theobromine, caffeine, and ECG changed minimally throughout all the processes. For changes in the catechin and purine alkaloid contents of the green tea leaves during storage, EGCG, ECG, and CAF decreased considerably in the green tea stored at temperatures of $5^{\circ}C$ and $25^{\circ}C$, and they decreased by $20{\sim}30%$ after storage for 1 year. However, a quantitative difference was hardly observed in the catechin and alkaloid contents regardless of storage temperature.

• Food Science and Preservation
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• v.11 no.1
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• pp.22-27
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• 2004

In order to endow mackerel fillet with antioxidant effect, functionality and remove fishy smell, chitosan, oligosaccaride, extracts of green tea, dill weed and ginger was used as soaking solution additives. Quality characteristics of soaked mackerel fillet(SMF) was investigated during storage temperature and time after vacuum packing with polyvinyl chloride film. From the results of VBN measurement, initial spoilage was showed within 2 or 3 weeks in SMF soaked with brine including extracts of green tea, herb and ginger at 5$^{\circ}C$. In case of adding chitosan and oligosaccarides to the solution mentioned above, initial spoilage was found from 4 to 7 weeks, oxidation was reduced remarkably and SMF stored at -20$^{\circ}C$ maintained the freshness during 80 days. Viable cell counts were reached to 108 for 3 weeks storage at 5 and 0$^{\circ}C$. But no change of viable cell counts was founded at -20$^{\circ}C$. The shelf-lifes of SMF according to 5, 0 and -20$^{\circ}C$storage temperatures were 2 to 3, 4 to 7 weeks and about 3 months, respectively.

• Food Science and Preservation
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• v.19 no.4
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• pp.510-518
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• 2012

In this research, to modernize traditional food and to make functional bokryung-byung, bokryung-byungwas made with Poriacocos Wolf powder added. During its storage, its moisture content ranged from 42.89 to 44.85%. The control group had the highes tmoisture content (44.85%), and it was reduced significantly as the Poriacocos Wolf powder in creased. The longer the storage period was, the lower the pH and the higher the acidity was. The total bacterial count increased from 2.70 to 3.00 Log CFU/g right after the manufacture and increased rapidly on the fourth day of the storage with more than 7.00 Log CFU/g. There was no difference between the control group and the bokryung-byung, though. The Hunter's color value after the manufacture, with the increase in the added Poriacocos Wolf powder, showed a significantly reduced brightness, but significantly increased redness and yellowness. Their chromaticity did not change, how ever, during their storageat a temperature of $20^{\circ}C$. The hardness, solidity, gumminess, and cohesiveness of the bokryung-byung increased, unlike in the control group, and its brittleness increased. In terms of the overall preference, the preference for the control group was high, but was higher when 5 % Poria cocos Wolf powder was added during the manufacture of the bokryung-byung. As a result of these correlations, it is believed that elastic and chewy dduks are preferred and bokryung-byungs could be developed as functional dduks.

• Journal of Marine Life Science
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• v.5 no.1
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• pp.25-33
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• 2020

The Asan Bay, which has semi-diurnal tide with macro-tidal range, is affected by both freshwater discharge from the sluice gates in the sea dikes and tidal seawater inputs from the Yellow sea. Understanding water quality change in response to tides is important since tides can impact the short-term variations in physical and chemical water properties as well as the response of biological properties. The diel variations in water quality were seasonally investigated at 2 hour intervals from a fixed station in the Asan Bay. In the results, water temperature and salinity consistently fluctuated in phase or out of phase with tidal height. Especially salinity was positively correlated with tidal height. The concentrations of total suspended solids were higher in the bottom water than in the surface and fluctuated greatly over the tidal cycle recording higher values at low tide than at high tide. Nitrite+nitrate levels also fluctuated out of phase with tidal height and correlated negatively with tidal height. Other nutrients also showed a similar pattern. The pattern was distinct in July when freshwater was discharged before the field sampling. The concentrations of organic materials, total nitrogen and total phosphorus greatly fluctuated over the tidal cycle and were generally out of phase with tidal height. Most materials except particulate organic forms were correlated with salinity indicating that freshwater inputs were sources for the materials similarly to the dissolved inorganic nutrients. The results suggest that water quality (except dissolved oxygen and pH) and nutrients including organic materials was largely affected by tides in the Asan Bay.

• Korean Journal of Ichthyology
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• v.29 no.3
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• pp.165-175
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• 2017

To minimize the damage caused by summer season such as high temperature and red tide, this study was conducted to investigate the effect of feeding and starvation on the survival rate, growth, growth restoration and physiological response of red seabream Pagrus major which were reared in marine net cage ($6m{\times}6m{\times}6m$). The feeding group was fed throughout the experiment for 10 weeks, whereas starvation group was not fed for 6 weeks and subsequent refeeding for 4 weeks. Survival rates of feeding and starvation groups were 94.4% and 98.1% respectively. The growth rate of starvation group was significantly lower than feeding group during starvation period, but recovered rapidly after feeding. The nutritional status such as albumin, total protein, total cholesterol, triglyceride also showed similar tendency to the growth data. Hematocrit and hemoglobin levels were higher in the feeding group than the starvation group during starvation period. Aspartate aminotransferase, glucose and total cholesterol were rapidly increased at the same time (in 5 week) in feeding group, whereas starvation group did not significant difference during starvation period. It was shown that the feeding group is more sensitive to stress than the starvation group. Thus, starvation can be applied as a rearing management plan of net cage fish farm in summer season.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.4
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• pp.103-112
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• 1991

In this study, a numerical model was established and applied to simulate the steady-state groundwater and heat flow in an isotropic, heterogeneous, three dimensional aquifer system with uniform thermal properties and no change of state. This model was developed as an aid in screening large groundwater-flow systems as prospects for underground waste storage. Driving forces on the system are external hydrologic conditions of recharge from precipitation and fixed hydraulic head boundaries. Heat flux includes geothermal heat-flow, conduction to the land surface, advection from recharge, and advection to or from fixed-head boundaries. The model uses an iterative procedure that alternately solves the groundwater-flow and heat-flow equations, updating advective flux after solution of the groundwater-flow equation, and updating hydraulic conductivity after solution of the heat-flow equation. Dierect solution is used for each equation. Travel time is determined by particle tracking through the modeled space. Velocities within blocks are linear interpolations of velocities at block faces. Applying this model to the groundwater-flow system located in Jigyung-ri. Songla-myun, Youngil-gun. Kyungsangbuk-do, the groundwater-flow system including distribution of head, temperature and travel time and flow line, is analyzed.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.770-775
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• 1994

Kimchi packed in polypropylene(PP) tray was stored at different temperatures (0, 10, $20^{\circ}C$) to investigate the relationships between fermentative gas pressure and quality changes. The quality of Kimchi during storage was evaluated in terms of pH, titratable acidity, color, and sensory properties. The fermentative gas pressure changes due to $CO_2$ evolution showed typical sigmoidal curves at each temperature. Accordingly, inflation of Kimchi packages caused by increasing gas pressure occurred in 40 hours, 5 and 30 days at 20, 10, $0^{\circ}C$ , respectively, at which gas pressure inside the packages ranged $1.2{\sim}1.4\;psig$. Following inflation, Kimchi packages stored at 20 and $10^{\circ}C$ were burst out on 3 and 8 days, but those at $0^{\circ}C$ were not. As the fermentative gas pressure increased, pH decreased (r > 0.968) and titratable acidity increased (r > 0.973) proportionally. Regarding to the color change of crushed Kimchi juice, L and b values were decreased exponentially, but a value remained constant during storage. Among sensory properties, the sourness and texture scores showed good accordance with pH changes. In conclusion, although Kimchi kept optimal tastes during storage, the inflation of package restricted shelf-life of Kimchi.

• Tunnel and Underground Space
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• v.19 no.3
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• pp.203-212
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• 2009

The prediction of near field behavior around an underground high-level radioactive waste repository is important for the repository design as well as the safety assessment. In this study, a sensitivity analysis for seven parameters consisted of design parameters and material properties was carried out using a three-dimensional finite difference code. From the sensitivity analysis, it was found that the effects of borehole spacing, tunnel spacing, cooling time and rock thermal conductivity were more significant than the other parameters. For getting a statistical distribution of buffer and rock temperatures around the repository, an artificial neural network, backpropagation, was applied. The reliability of the trained neural network was tested with the cases with randomly chosen input parameters. When the parameter variation is within ${\pm}10%$, the prediction from the network was found to be reliable with about a 1% error. It was possible to calculate the temperature distribution for many cases quickly with the trained neural network. The buffer and rock temperatures showed a normal distribution with means of $98^{\circ}C$ and $83.9^{\circ}C$ standard deviations of $3.82^{\circ}C$ and $3.67^{\circ}C$, respectively. Using the neural network, it was also possible to estimate the required change in design parameters for reducing the buffer and rock temperatures for $1^{\circ}C$.