• Journal of Microbiology and Biotechnology
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• v.4 no.1
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• pp.49-55
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• 1994

A fungal strain capable of producing extracellular cellulase was isolated from farmland. It was identified as Aspergillus niger, and named Aspergillus niger KKS. Production of cellulase and xylanase by the A. niger KKS was studied through a shake-flask culture. The effects of culture conditions such as inoculum size, temperature, pH, and medium composition on the cellulase and xylanase production were examined. The optimum temperature and pH for the enzyme production were $30^{\circ}C$ and pH 7.0, respectively. The optimized medium was composed of 2.0% (w/v) rice straw, 0.5% (w/v) proteose peptone, 0.5% (w/v) $KH_2 PO_4$, 0.05% (w/v) yeast extract, 0.01% (w/v) $CoSO_4 \cdot 7H_2O$, and 0.05% (w/v) $CuSO$_4$\cdot 5H_2O$. When the strain was incubated with the optimized medium, it gave the activities of endoglucanase, $\beta$-glucosidase, $\beta$-xylosidase, xylanase were 3.80, 4.20, 4.00, 80.0 (IU/mL), respectively. Filter paper and cotton activities were 0.68 and 0.045 (IU/mL), respectively. The results of this study show that A. niger KKS is a potential organism with a wide spectrum of enzyme activities, such as those of $\beta$-glucosidase, $\beta$-xylosidase, and xylanase.

• Korean Journal of Food Science and Technology
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• v.54 no.1
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• pp.75-79
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• 2022

Fresh, washed ginseng can be contaminated with microorganism loads as high as 6.5 log CFU/g for total bacteria and 4.3 log CFU/g for mold. The goal of this study was to test eight antibacterial agents on ginseng. Immersing fresh ginseng washed in 1% (w/w) sodium citrate, sodium diacetate, sodium acetate, citric acid, and sodium lactate solution for 1 h resulted in a bactericidal effect of 31.0-97.5% for total bacteria. Among the organic acids, sodium citrate had the best antibacterial effect, with total bacteria reduced from 6.5 log to 4.9 log CFU/g. A 1% (w/w) vitamin B₁ lauryl sulfate solution with surfactant function by hydrophilic and hydrophobic sites can reduce 2.7 log CFU/g (99.8% inactivation) on total bacteria. In the 1% (w/w) calcium oxide solution, total bacteria were reduced by 3 log, showing an excellent inactivation effect of 99.9%. Calcium oxide is a highly useful material for inactivation of microorganisms in fresh ginseng.

• Korean Membrane Journal
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• v.4 no.1
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• pp.20-24
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• 2002

The surface of polysulfone membranes has been modified using the fluorine chemicals, ITFE (2-iodo-1,1,1-trifluoro-ethane F.W.=209.94) and PFPI (1H,1H-pentafluoro-n-propyl iodide F.W.=259.95), and PFI (1H,1H,2H,2H-perfluorohexyl iodide, F.W.=373.99) based on Friedel-Crafts reaction mechanism with varying reaction temperatures, reaction time, and catalysis types. The resulting membranes were characterized through mainly the contact angle measurement and pure water permeability. The smaller reactant shows the larger contact angles. FeBr$_3$ catalyst is more effective than AlCl$_3$. Typically, the PS film treated with ITFE at $25^{\circ}C$ under FeBr$_3$ catalyst showed the contact angle 78.5$^{\circ}C$ which indicated 10% over the value of unreacted PS films. More than 50% of pure water flux 8.0 g/$m^2$hr, reduced at reaction time 10 min relative to the original flux, 3.49 g/$m^2$hr.

• Journal of Applied Biological Chemistry
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• v.58 no.1
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• pp.81-88
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• 2015

To characterize the culture medium for the biosurfactant production by Bacillus pumilus IJ-1, the influences of various carbon, nitrogen and mineral sources were assessed. As a result, the highest biosurfactant production was observed after 96 h cultivation containing 0.5% (w/v) tryptone. The strain was able to grow and produce biosurfactant at 0-10% (w/v) NaCl, in the pH range of 5-10, and at $20-45^{\circ}C$. Optimal culture conditions for the biosurfactant production were at $20^{\circ}C$ and pH 9.0 after 72 h incubation and the surface tension of biosurfactant was 27.0 dyne/cm.

• Microbiology and Biotechnology Letters
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• v.18 no.6
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• pp.599-606
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• 1990

A chitinase-producing bacterium, Aeromonas salmonicida YA7-625, was isolated from domestic seashore muds. The preferable medium composition for the production of chitinase was as follows: colloidal chitin 1.26% (w/v), tryptone 2.95% (w/v), $MgSO_4-7H_20$ 0.15% (w/v) and $K_2HP0_4$, 0.15% (w/v) (pH 8.5). The highest enzyme production was observed after cultivation of 48 hours at 27OC. The chitinase of Aeromonas salmonicida YA7-625 was purified successively by ammonium sulfate precipitation, affinity adsorption, hydroxylapatite column chromatography and gel filtration. The optimal temperature and pH for the activity of purified chitinase were $50^{\circ}C$ and 7.0, respectively. The molecular weight of purified chitinase was ca. 200,000 daltons and apparent Km value of it was 1.276 mglml on colloidal chitin.

• Korean Journal of Crystallography
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• v.12 no.3
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• pp.141-144
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• 2001

From the reaction of Na[Ga(N₃)₄] with PPh₃, an ionic compound [Ph₃P(OH)]/sup +/[N₃]/sup -/ (1) was isolated. Compound 1 was characterized by spectroscopy (¹H-NMR, /sup 13C{¹H}-NMR, and IR) and X-ray diffraction. Crystallographic data for 1 : orthorhombic space group P2₁2₁2₁, a = 10.491 (4) Å, b=11.603(5)Å, c=13.149(5)Å, Z=4, R(wR₂)=0.0547(0.0978).

• Bulletin of the Korean Chemical Society
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• v.7 no.4
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• pp.318-320
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• 1986

• Journal of the Korean Mathematical Society
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• v.54 no.5
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• pp.1379-1410
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• 2017

Kang and Ko introduced a skew-symmetrizable matrix to describe a structure theorem for complete intersections of grade 4. Let $R=k[w_0,\;w_1,\;w_2,\;{\ldots},\;w_m]$ be the polynomial ring over an algebraically closed field k with indetermiantes $w_l$ and deg $w_l=1$, and $I_i$ a homogeneous perfect ideal of grade 3 with type $t_i$ defined by a skew-symmetrizable matrix $G_i(1{\leq}t_i{\leq}4)$. We show that for m = 2 the Hilbert function of the zero dimensional standard k-algebra $R/I_i$ is determined by CI-sequences and a Gorenstein sequence. As an application of this result we show that for i = 1, 2, 3 and for m = 3 a Gorenstein sequence $h(R/H_i)=(1,\;4,\;h_2,\;{\ldots},\;h_s)$ is unimodal, where $H_i$ is the sum of homogeneous perfect ideals $I_i$ and $J_i$ which are geometrically linked by a homogeneous regular sequence z in $I_i{\cap}J_i$.

• Journal of Practical Agriculture & Fisheries Research
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• v.4 no.1
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• pp.128-137
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• 2002

This study was conducted to develop the heat exchanger by utilizing the heat energy of underground water(15℃), which might be used for cooling and heating system of the agricultural facilities. We developed the heat exchanger by using the parallel type plat fin tube made of Aluminum(Al 6063), which was named Aloo-Heat(No. 0247164, offered by Korean Intellectual property Office). The trial manufactures were made from Aloo-heat which was 600mm, 700mm length respectively, and It were welded to the end "U" type in order to direct flow of the underground water. The performance test was carried out under the condition of open space and room temperature with the change of flow rate of the underground water and air. The results are as follows. 1. The trial manufactures had convection heat value from 33 to 156 W/m²℃, and It was coincided with design assumption. 2. The amount of energy transfer was increased with the increment of the area of heat transfer, the air flow, the gap of temperature inlet & outlet the underground water and the air. 3. The heat value was 6,825W when the air flow was 6,000m³/h and the gap of temperature between inlet and outlet of the underground water was 6℃, and It dropped from 25.8℃ to 23.2℃(-2.6℃ difference). The convection heat value was 88.5W/m²℃. 4. The heat value was 2.625W when the air flow was 4,000m³/h and the gap of temperature between inlet and outlet the underground water was 2℃, and It dropped from 27℃ to 22.5℃(-4.5℃ difference). The convection heat value was 33.6W/m²℃. 5. Correlation values(R²) of the testing heat values of the trial manufacture type I, II, and III were 0.9141, 0.8935, and 0.9323 respectively, and correlation values(R²) of the amount of the air flow 6,000m³/h, 5,000m³/h, 4,000m³/h were 0.9513, 0.9414, and 0.9003 respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.1
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• pp.42-49
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• 1996

The author examined the response of Armorclad rockfish, Sebastes hubbsi [MATSUBARA]to the surface attracting lamps (0.5W, 0.8W, 1W) line in the experimental water tank ($550L{\times}58W{\times}73H$cm). The attraction rate was investigated in accordance with the intervals of lighting and putting out hour (1,5 minute) when each of the attraction lamps was gradually switched off after they were switched on all at once. The results are as follows : 1. Total distribution rate of fish in the illuminated section was 61.6%(mean 12.3%) in case of 1 minute interval, and 41.0%(mean 8.2%) in case of 5 minutes interval. 2. Mean distribution rate of fish at the illuminated section : \circled1Distribution rate at interval of 1 minute were 12.7% in 0.8W, 12.4% in 0.5W and 11.9% in 1 W respectively. \circled2Distribution rate at interval of 5 minutes were 9.0% in 1W, 8.6% in 0.8W and 7.0% in 0.5W respectively. 3. Attraction rates of the last section showed a little increasing as illuminating time elapsed. A difference of attraction rates according to lighting source in 1 minute interval was bigger than that in 5 minute interval. 4. Attraction rate of fish in only last section switched on : \circled1Attraction rate at interval in case of 1 minute were 52.0% in 0.8W, 46.7% in 0.5%W and 45.3% in 1W respectively. \circled2Attraction rate at interval in case of 5 minutes were 32.0% in 1W, 24.0% in 0.8W and 14.7% in 0.5W respectively.