• Applied Biological Chemistry
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• v.22 no.3
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• pp.135-141
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• 1979

These experiments were conducted to investigate the conditions of the acid protease production by Rhizopus oryzae and the characteristics of crude enzyme. The results obtained were as follows: 1. The optimum culture time and the optimum amount of added water to the wheat bran medium were about 48 hrs and $80{\sim}120%$, respectively. 2. The addition of $(NH_4)_6Mo_7O_{24},\;(NH_4)_2SO_4,\;NH_4NO_3$, casein, and albumin, respectively, as nitrogen sources to the wheat bran medium was effective. Of these, the optimum concentrations of addition of $(NH_4)_6Mo_7O_{24}$ and casein which were the most effective were 0.1% and 1.0%, respectively. 3. The addition of glucose, galactose, maltose, lactose, and soluble starch, respectively, as carbon sources to the wheat bran medium was effective. Of these, the optimum concentration of addition of glucose which was the most effective was 3.0%. 4. The addition of $KH_2PO_4$ as a phosphate salt to the wheat bran medium was effective. The optimum concentration of addition of $KH_2PO_4$ was 0.3%. 5. The optimum pH for the enzyme action was 2.4, the optimum temperature about $40^{\circ}C$, and the stable pH range $2.0{\sim}5.0$. The enzyme was stab1e below $40^{\circ}C$. 6. The enzyme activity increased rapidly for 10 minutes after addition, thereafter it increased slowly. 7. The enzyme activity increased rapidly to 2 ml of addition, but nearly did not increase at the amounts greater than 2ml.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.4
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• pp.192-205
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• 2009

The unexpected wind over the Mt. Hwawang on 9 February 2009 was deadly when many spectators were watching a traditional event to burn dried grasses and the fire went out of control due to the wind. We analyzed the fatal wind based on wind flow simulations over a digitized complex terrain of the mountain with a localized heating area using a three dimensional computational fluid dynamics model, CFD_NIMR_SNU (Computational Fluid Dynamics_National Institute of Meteorological Research_Seoul National University). Three levels of fire intensity were simulated: no fire, $300^{\circ}C$ and $600^{\circ}C$ of surface temperature at the site on fire. The surface heat accelerated vertical wind speed by as much as $0.7\;m\;s^{-1}$ (for $300^{\circ}C$) and $1.1\;m\;s^{-1}$ (for $600^{\circ}C$) at the center of the fire. Turbulent kinetic energy was increased by the heat itself and by the increased mechanical force, which in turn was generated by the thermal convection. The heating together with the complex terrain and strong boundary wind induced the unexpected high wind conditions with turbulence at the mountain. The CFD_NIMR_SNU model provided valuable analysis data to understand the consequences of the fatal mountain fire. It is suggested that the place of fire was calm at the time of the fire setting due to the elevated terrain of the windward side. The suppression of wind was easily reversed when there was fire, which caused updraft of hot air by the fire and the strong boundary wind. The strong boundary wind in conjunction with the fire event caused the strong turbulence, resulting in many fire casualties. The model can be utilized in turbulence forecasting over a small area due to surface fire in conjunction with a mesoscale weather model to help fire prevention at the field.

• Journal of Sericultural and Entomological Science
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• v.45 no.1
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• pp.10-17
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• 2003

This study was carried out to analyze physicochemical characteristics of sericin cocoon from silkworm, Bombyx mori. The degumming loss increased with increasing treatment time up to 2 hr, and temperature up to 130$^{\circ}C$. At 130$^{\circ}C$, degumming loss of Nd-s jam and Nd$\^$H/ jam were 100% while that of Baegok jam was 24%. Nd-s jam and Baegok jam ha high glycine content of 29.1∼46.3 mol% where as Nd$\^$H/ jam had high serine content of 32.6 mol%. Thermal denaturation temperatures were found at 218$^{\circ}C$ for Nd-s jam, 216$^{\circ}C$ for Nd$\^$H/ jam, and 218$^{\circ}C$ for Baegok jam. Before degumming, crystallinities obtained by FT-IR analysis were 44.3, 43.7, and 59.9% for Nd-s jam, Nd$\^$H/ jam, and Baegok jam respectively. After degumming, crystallinity increased to 61.8% for Baegok jam. Before degumming, crystallinitics obtained from XRD were 35.9, 33.5, and 47.2%, for Nd-s jam, Nd$\^$H/ jam, and Baegok jam. After degumming, crystallinity increased to 49.8% for Baegok jam. The molecular weight of Nd$\^$H/ jam were 9,417 in 1 hr, 3,744 in 2 hr, 4,944 in hr, and 3,910 in 6 hr.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.253-258
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• 2006

An empirical model of nitrous oxide emission from agricultural soil has been applied. It is based on the relationship between $N_2O$ and three soil parameters, soil mineral N(ammonium plus nitrate) content in the topsoil(0-15cm), soil water-field pore space, and soil temperature, determined in a study on clay loam and sandy loam at the pepper field in 2004. For comparisons between estimated and observed values of $N_2O$ emissions in the pepper field, it was investigated that $N_2O$ amount in the clay loam and sandy loam were overestimated as 12.2% and less estimated as 30%, respectively. However, $N_2O$ emissions were overestimated as 27.1% in the clay loam and 14.7% in the sandy loam from $N_2O$ gas samples collected once a week at the same time analyzing soil parameters. This modelling approach, based as it is well established and widely used soil measurements, has the potential to provide flux estimates from a much wider range of agricultural sites than would be possible by direct measurement of $N_2O$ emissions.

• Journal of the Korean Vacuum Society
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• v.18 no.4
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• pp.318-330
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• 2009

A high heat flux test facility using a graphite heating panel was constructed and is presently in operation at Korea Atomic Energy Research Institute, which is called KoHLT-1. Its major purpose is to carry out a thermal cycle test to verify the integrity of a HIP (hot isostatic pressing) bonded Be mockups which were fabricated for developing HIP joining technology to bond different metals, i.e., Be-to-CuCrZr and CuCrZr-to-SS316L, for the ITER (International Thermonuclear Experimental Reactor) first wall. The KoHLT-1 consists of a graphite heating panel, a box-type test chamber with water-cooling jackets, an electrical DC power supply, a water-cooling system, an evacuation system, an He gas system, and some diagnostics, which are equipped in an authorized laboratory with a special ventilation system for the Be treatment. The graphite heater is placed between two mockups, and the gap distance between the heater and the mockup is adjusted to $2{\sim}3\;mm$. We designed and fabricated several graphite heating panels to have various heating areas depending on the tested mockups, and to have the electrical resistances of $0.2{\sim}0.5$ ohms during high temperature operation. The heater is connected to an electrical DC power supply of 100 V/400 A. The heat flux is easily controlled by the pre-programmed control system which consists of a personal computer and a multi function module. The heat fluxes on the two mockups are deduced from the flow rate and the coolant inlet/out temperatures by a calorimetric method. We have carried out the thermal cycle tests of various Be mockups, and the reliability of the KoHLT-1 for long time operation at a high heat flux was verified, and its broad applicability is promising.

• Journal of the Mineralogical Society of Korea
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• v.19 no.1 s.47
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• pp.15-29
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• 2006

Synthetic Mn-tourmalines (tsilaisite) were obtained by hydrothermal synthesis under the condition of 2 Kbar, $375{\sim}700^{\circ}C$, and 50 day-run-time with complete substitution of Mg in dravite by Mn (Mn%=0, 25, 50, 75, and 100%). They are all 6 samples containing Mn-tourmaline with some amounts of albite, spessartine, rhodocrosite, phlogopite etc, showing different synthetic condition of temperature and Mn composition. Synthetic Mn-tourmalines are of site deficiency in X-site ($0.53{\sim}0.68$) more than that of natural ones (approx. $0.2{\sim}0.3$) and show Mn cations occupying Y-site less than expected with initial experiments, leading to failure in synthesis of end-member tsilaisite. Rietveld structural refinements reveal that $R_{wp}$ ($R_{p}/R_{exp}$) is in the range of 13.35 and 18.62%, $R_{B}$ and S (CofF) are $4.85{\sim}6.25%$ (S-18: 8.57%), $1.31{\sim}1.59$ (S-18: 1.81), respectively. Unit cell parameters (space group R3m, z=3) are ${\alpha}=15.8994\;{\AA}$ and $c=7.1846\;{\AA}$ in average (S-18: ${\alpha}=15.9491\;{\AA},\;c=7.1773\;{\AA}$). Average bond lengths of and are $2.67{\sim}2.69\;{\AA}$ (S-18: $2.65\;{\AA}$) and $2.00{\sim}2.02\;{\AA}$ (S-18: $1.96\;{\AA}$), respectively. Ditrigonality (${\delta}$) are in the range of 0.022 and 0.031 (S-18: 0.061), indicating degrading symmetry with increase of Mn content.

• Korean Journal of Ecology and Environment
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• v.36 no.2 s.103
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• pp.124-138
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• 2003

This paper aimed to analyze the relationship between alga3 bloom patterns and hydrological, limnological data which were collected from major reservoirs in Korea for 8 years (1990${\sim}$1997). Water temperature of river-type reservoirs showed wider seasonal fluctuations than that of lake-type. pH of lake-type reservoirs was low in winter season but high in summer season. In contrast, river-type reservoirs showed high pH in spring and autumn seasons as well, and very low in summer season. COD of lake-type reservoirs and Paldang reservoir was lower (2${\sim}$3 mg/L) than that of Geumgang and Nagdonggang reservoirs (6${\sim}$9 mg/L). Dissolved oxygen (DO) of river-type reservoirs was higher than that of lake-type reservoirs. Seasonal fluctuation pattern of DO saturation in river-type reservoirs was high (80 ${\sim}$100%) and remained relatively constant whereas lake-type reservoirs showed the highest level (93%) in late spring or early summer, which gradually decreased entering winter season(46${\sim}$06%). And monthly variation of DO saturation showed inverse proportion to water volume in lake-type reservoirs. Nutrients concentration in river-type lake is higher than lake-type. Seasonal fluctuation of nutrients (T-N, T-P) in lake-type reservoirs was relatively small than that of river-type reservoirs. Annual mean N/P mass ratio of lake-type reservoirs was higher than that of river-type. Transparency tended to related with the suspended solid concentration in river-type reservoirs. Algal bloom of lake-type and river-type reservoirs occurred at any time except rainfall and winter periods. And it dominated in summer and early autumn, respectively. Algal bloom of river-type reservoirs was higher than that of lake-type. Relationship between rainfall and chlorophyll- a in lake-type reservoirs was relatively high, however river-type reservoirs showed insignificant.

• The Korean Journal of Food And Nutrition
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• v.18 no.4
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• pp.341-348
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• 2005

The quality characteristics of bread added with the levels of $0\%,\;1.0\%,\;2.0\%\;3.0\%\;and\;4.0\%$ prickly pear powder were investigated. Mixing water absorption capacity was increased by increasing amounts of prickly pear powder. Mixing time of dough was increased compared to that of wheat flour by added prickly pear powder, while it decreased as prickly pear powder content increased. Dough stability of wheat flour added with $1.0\%$ prickly pear powder was similar to wheat flour dough, while decreased by increasing amount of prickly pear powder at the range of $2.0\~4.0\%$. Pasting temperature($66.1\~66.9^{\circ}C$) of wheat flour added with $1.0\%,\;2.0\%\;3.0\%\;and\;4.0\%$ prickly pear powder was lower($67.8^{\circ}C$) than that of wheat flour. Peak viscosity($2,226\~2,375$ cp) of wheat flour added with $1.0\%,\;2.0\%\;3.0\%\;and\;4.0\%$ prickly pear powder were higher(2,288 cp) than control, and increased with increasing amount of prickly pear powder Setback($797\~750$ cp) of wheat flour added with $1.0\%,\;2.0\%\;3.0\%\;and\;4.0\%$ prickly pear powder were lower(803 cp) than that of wheat flour, and decreased with increasing amount of prickly pear powder. The volume of dough added with prickly pear powder decreased compared to that of the wheat dough. The specific loaf volume of bread added with prickly pear powder decreased($8.0\~18.5\%$) compared to that of the wheat bread. Color of crumb was deep red gradually with the increasing amount of substituted prickly pear powder. Hardness, adhesiveness, gumminess and chewiness of bread were increased gradually with the increasing amount of substituted prickly pear powder but the springiness was decreased. The sensory evaluation showed that bread of wheat flour added with $2.0\%$ prickly pew powder was superiority than the wheat flour bread.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.459-465
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• 2002

To obtain the basic data for commercial 10% salted egg yolk for mayonnaise preparation, 3 types of egg yolks [pasteurized egg yolk (Yolk A)-not salted, pasteurized before salting (Yolk B)-salted, and pasteurized after salting (Yolk C)-salted] were prepared, and the changes in quality characteristics of these egg yolks with frozen storage were tested. The results obtained were as follows; Yolk A gelatinized during frozen storage, thus could not used for mayonnaise preparation. The viscosity of the egg yolk increased $3{\sim}5$ times after salting. Viscosity of the salted egg yolk increased with frozen storage time. Viscosity of Yolk B was higher at $-20^{\circ}C$ than $-15^{\circ}C$. Viscosity of Yolk C, however, was higher at $-15^{\circ}C$ than $-20^{\circ}C$. Frozen storage of pasteurized salted egg yolk showed some effects on the emulsification capacity. The effect, however, was smaller than that of unpasteurized salted egg yolk. Microbes of salted egg yolk were decreased with frozen storage, but there was no difference between Yolk B and Yolk C. It was suggested that commercially pasteurized 10% salted egg yolk for mayonnaise preparation can be successfully stored for 12 months at the temperature of $-15{\sim}-20^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1048-1056
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• 2002

Quality of fresh ginger deteriorates rapidly during low temperature storage, and its storage life is short due to sprouting and microbial spoilage. The objectives of this research were to develop, using additives, a minced ginger product, which could maintain acceptable quality for over 30 days, and to investigate its quality changes during the cold storage. Storage stability of minced ginger product was investigated from the standpoint of the inhibition of brown discoloration, gas formation and liquid-solid separation. Fresh ginger was peeled and ground to produce minced ginger (control). Sodium bisulfite, L-cysteine, NaCl, sodium benzoate, modified starch, and/or xanthan gum were added to the control to minimize quality loss during storage, and to develop an optimum formula (A) of minced ginger. Samples were packed in Nylon/PE films, stored at $5^{\circ}C$, sampled at a 30-day interval, and subjected to quality evaluations. Changes in pH, surface color, gas formation, liquid-solid separation, contents of free amino acids, free sugars, organic acids, and fatty acids were determined. Gas formation was effectively inhibited in samples with sodium benzoate and/or NaCl. Samples with xanthan gum did not result in liquid-solid separation. L-Cysteine and sodium bisulfite were effective in controlling discoloration. pH decreased during storage in all samples, except sample A. Organic acid contents of all samples increased during storage, with lactic acid content showing the highest increase. Free amino acid content decreased with increasing storage time. Free sugar content of all samples decreased during storage. Sensory results showed sample A maintained acceptable quality until 90 days of storage. These results suggest that quality of minced ginger could be successfully maintained with the additions of selected additives for up to 90 days.