• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.265-275
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• 2013

Variances in environmental factors were followed in Ilwol reservoir, Suwon, during bloom of Microcystis aeruginosa (K$\ddot{u}$tzing) K$\ddot{u}$tzing, Cyanophtya from August to October, 2011. M. aeruginosa dominated the water column throughout the investigation period. The water temperature varied from $25.7^{\circ}C$ to $28.4^{\circ}C$, pH 8.40 to 11.17, CODcr 4.25 to $72.00mg\;L^{-1}$, electrical conductivity 333.1 to $749.0{\mu}g\;cm^{-1}$, and Chl-a 22 to $185mg\;L^{-1}$. In particular, the high levels of CODcr is likely indicate high contribution of autochthonous organic matters in the reservoir. TN varied from 28.86 to $56.75mg\;L^{-1}$, TP 0.20 to $1.24mg\;L^{-1}$, Fe 0.11 to $1.05mg\;L^{-1}$, and Si 3.13 to $7.46mg\;L^{-1}$. These increases imply constant accumulation in Ilwol reservior, and reinforce the idea of autochthonous organic matters input in the reservoir. The Korea Trophic Status Index ($TSI_KO$) varied from 37.19 to 147.22. Trophic levels varied from mesotrophic to hypertrophic level, and differed spatio-temporally. Therefore, it is concluded that $TSI_KO$ is useful for analyzing trophic status of reservoirs.

• Korean Journal of Ichthyology
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• v.10 no.1
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• pp.1-10
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• 1998

The early history of Korean mandarin fish, Siniperca scherzeri was studied to obtain some information required in aquaculture and reinforcement of natural population. During the period from June 1996 to July 1997, the mature adults of Siniperca scherzeri were collected from the middle Soyang Lake at Puksan - myon, Chunchon - shi, Kangwon - do, Korea. The eggs from females were obtained by injecting HCG or/and GnRH - a and fertilized by dry method in the laboratory. The fertilized eggs, measuring 1.70~2.10 mm in diameter and expanded to 2.20~2.66mm after absorption of water, were globosity, light orange yellow, separative, submergence and had one large oil globules of 0.5~0.7 mm. The blastodisc was formed in 1 hour and cleavage started in 1 hour 30 min. after fertilization, and the intervals of each stage of cleavage was about 50 min. at the water temperature of $21{\sim}24^{\circ}C$. Hatching occurred 131 hours 30 min. after fertilization and newly hatched larvae were 5.86~6.85 mm in total length(TL) and numerous stellate melanophores were distributed on the yolk and abdomen of caudal peduncle. The yolk was almost absorbed and the teeth development. 3 days after hatching, at 6.98~7.60 mm TL. The head spines and the teeth were largely developed and all fins were completely formed and became postlarva stage 15 days after hatching, at 10.10~12.90 mm TL. The body shape and the color pattern were similar to adult, 25 days after hatching, at 15.3~23.8 mm TL. In 5 months after hatching were reached at 154.10~175.02 mm TL and 49.32~82.67 g in body weight.

• Korean Journal of Ichthyology
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• v.29 no.1
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• pp.52-61
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• 2017

The egg development and early life history of Korean endemic fish, Squalidus multimaculatus (Gobioninae), were investigated. The eggs from the females were obtained by injecting 10 IU/g of human chorionic gonadotropin and inseminated by wet method in the laboratory. The fertilized eggs were 0.8~0.9 mm in diameter and had no oil globules. The embryo began to hatch about 65 hrs after fertilization under water temperature of $24{\pm}1^{\circ}C$. The newly-hatched larvae were 2.5~3.1 mm in total length, and their mouth and anus were not opened. Four days after hatching, the postlarva were 4.0~4.2 mm in total length, and their york sacs were completely absorbed. They entered the juvenile stage when all fin-rays were formed at 30 days after hatching, and their total length were 11.2~15.7 mm. At 45 days after hatching, the external from of juveniles were similar to those of adults (total length were 18.8~22.5 mm), and 80 days after hatching, the external characteristics from of juveniles were same to adults (total length were 25.7~35.9 mm).

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.215-224
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• 2018

Influences of the magnetic field on 5, 10 and 15 wt% (1.5, 3 and 4.5 M) HCl solution behaviour, which has widespread applications in petroleum well acidizing, were investigated in various conditions. Differences in the pH of magnetized hydrochloric acid compared to that of normal hydrochloric acid were measured. Taguchi design of experimental (DoE) method were used to model effects of the magnetic field intensity, concentration, velocity and temperature of acid in addition to the elapsed time. The experimental results showed that the magnetic field decreases [$H^+$] concentration of hydrochloric acid up to 42% after magnetization. Increasing the magnetic field intensity (with 28% contribution), concentration (with 42% contribution), and velocity of acid increases the effect of magnetic treatment. The results also demonstrated that the acid magnetization was-not influenced by the fluid velocity and heating. It was also displayed that the acid preserves its magnetic memory during time. The optimum combination of factors with respect to the highest change of [$H^+$] concentration was obtained as an acid concentration of 10% and an applied magnetic field of 4,300 Gauss. Due to the reduction of HCl reaction rate under the magnetization process, it can be proposed that the magnetized HCl is a cost effective and reliable alternative retarder in the matrix acidizing of hydrocarbon (crude oil and natural gas) wells.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.69-69
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• 2002

Transgenic animals production tools have been valuable for research and purpose. The current methods of gene transfer, microinjection and nuclear transfer, which are widely used in transgenic animal production, but all most methods has only had limited success in production of larger species. Here, we report the possibility of a sperm-mediated gene transfer method in porcine embryos. Oocytes were collected from ovaries harvested at a local slaughterhouse were matured in 500${mu}ell$ drops of TCM-199 under mineral oil at 38.5$^{\circ}C$ in a humidified atmosphere of 5%CO2 in air. After 42-43h of in vitro maturation oocytes were denuded. for sperm injection into the cytoplasm of the porcine oocytes, sperm suspension in NIM medium are subjected extraction with TritonX-100 before mixing with a green fluorescent gene (GFP). Sperm with Tritonx-100 were prepared by adding TritonX-100 to a final volume of 0.05% in the sperm suspension and mixing by trituration for 60s before two wishes in NIM medium at 2$^{\circ}C$. A(ter wishing, sperm were mixed with TritonX-100 at $25^{\circ}C$ followed by washes at 2$^{\circ}C$. Sperm were resuspended in ice cold NIM to a final volume of 400${mu}ell$ and 2-20ng/${mu}ell$ DNA were triturated on ice for 60s. All microinjection was performed in HEPES-buffered CZB medium at room temperature within 2h. After culture in NCSU-23 for 72h, percent of porcine embryos transfected GFP gene are 20.7%(6/29) in 20ng/${mu}ell$ sperm-DNA mixed group and other groups were 3.7 %(2/54)and 4.7%(3/67). These data suggests that sperm-mediated gene transfer method should be used to the production tool of transgenic pig efficiently.

• Journal of Mushroom
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• v.16 no.3
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• pp.131-139
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• 2018

The king oyster mushroom (Pleurotus eryngii) is widely consumed because of its flavor, texture, and its functional properties such as antioxidant activity and prebiotic effects. However, long-term product storage and transportation (e.g., export) are difficult because of its limited durability. The shelf-life of king oyster mushroom is affected by environmental factors such as temperature, humidity, gas composition, and ventilation, which may affect sensory characteristics including respiration rate, texture, moisture, flavor, color, and pH. The major problems regarding storage of mushrooms are browning, flavor changes, and softening. To address these problems, novel preservation techniques were developed, and more durable variants were bred. Different drying methods, gamma irradiation, chitosan coating, modified atmosphere (MA) packaging, and controlled atmosphere (CA) storage were evaluated in order to extend the shelf-life of king oyster mushrooms. Freeze drying showed better results for the preservation of mushrooms than other drying methods. Irradiation with 1 kGy was more effective for extending mushroom shelf-life than higher doses. The preservative performance of chitosan-based films was improved by combining the compound with other hydrocolloids, such as oil, protocatechuic acid, and wax. The CA storage conditions recommended for king oyster mushrooms are 5kPa $O_2$ and 10 to 15kPa $CO_2$ at temperatures below $10^{\circ}C$. Active MA packaging with microperforated PP film was also effective for maintaining quality during storage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.5
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• pp.317-331
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• 1989

Chaenogobius laevis inhabit brackish waters. Adult male protects egg mass laid under the stones. The egg with small oil globule varied from 3.40 to 4.04 mm in diameter. When water temperature is $22.0\~23.0^{\circ}C$, larvae hatched about 113 hours after fertilization. The newly hatched larvae reared for 33 days grow up to 12.10 mm in total length and developed to the jevenile. When larvae length attained about 8.0 mm, jaw bones were more rapidly ossified than vertebrae and cranium.

• Journal of the Korea Organic Resources Recycling Association
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• v.7 no.2
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• pp.57-64
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• 1999

The purpose of this study is to establish effective conditions for controlling $CH_4$, $N_2O$ emission from organic Waste / wastewater treatment processes. Continuous and batch experiments were conducted to treat the micro algae from polluted and eutrophicated lakes through the thermophilic oxic process. The microalgae used were mainly Microcystis sp.(collected from eutrophic lake) and Chlorella sp. (cultured in laboratory) Wasted cooking oil was added by aid-heating source. Physico-chemical components of sludges and microalgae were analyzed. In batch experiments, air supply was changed from 50ml/min to 150ml/min. The temperature. water content and drained water were affected by the air flow rate at initial stage. However, there was almost no influence of air flow rate on them in middle and last stages. At air flow rate of 100ml/min, the degradation rate of organic material was higher than that at other air flow rates. $CO_2$ concentration in exhaust was proportional to the strength of aeration, especially at initial stage when degradation was active. $CH_4$ with low concentration was detected only at starting stage when air diffusion was not enough. $N_2O$ production was not affected by variation of air supply. In continuous experiments no matter what the dewatering methods (with PAC and without PAC) and media (wood chip and reed chip) were changed, $N_2O$ was almost not affected by variation of injected air. Result showed that the reed chips using for lake purification could be used as media for thermophilic oxic process in lake and marshes area. $CO_2$ concentration was not so much affected by the change of dewatering methods and media types. $CH_4$ was not detected in the experimental period. So it can be shown that the thermophilic oxic process had been well operated in wide handling conditions regardless of media and dewatering methods.

• Journal of Bio-Environment Control
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• v.10 no.4
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• pp.213-218
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• 2001

In 2000, domestic protected cultivation area was about 52,189 ha including 13,621 ha of heating greenhouses. Recently, heating cost accounts for 25 to 30% of total production cost which has been increased due to the rise of oil price, while the heating cost was about 15% in other advanced countries. To reduce the heating energy cost, the study of minimizing the heating space of greenhouse have been conducted from 1998 to 1999. The system was developed to control the heating space according to crop growth by moving horizontal curtain up and down. Installation of the heating space-control curtain in greenhouse decreased heating capacity to 264 m$^3$compared to 661.5 m$^3$in the traditional curtain, and consumpted fuel was saved about 56% point in semiforcing culture and 28% point in retarding culture of pepper. In addition, uniform distribution of air temperature and relative humidity in greenhouse environment resulted in earlier flowering and higher yields in hot pepper.

• Korean Journal of Microbiology
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• v.43 no.2
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• pp.83-90
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• 2007

Sphingomonas sp. KS 301, which was isolated from oil contaminated soil, was shown to have five different SODs (SODI, II, III, IV, V) which can be separated by DEAE-Sepharose chromatography, and SOD III was finally purified in this study by ammonium sulfate precipitation, DEAE-Sepharose chromatography, Superose 12 gel filtration and Uno-Q1 ion exchange chromatography. The molecular weight of SOD III was 23 kDa as determined by SDS-PAGE and the apparent molecular weight of the native enzyme was estimated to be approximately 71 kDa by Superose-12 gel filtration chromatography. These data suggest that the purified SOD consists of at least two subunits. The specific activity of the SOD III was higher than Mn type or Fe type SOD of Escherichia coli by 5 fold. To determine the type of SOD III, inhibitory effects of $NaN_{3},\;H_{2}O_{2},\;KCN$ were examined. 10 mM $NaN_{3}$ was able to inhibit 56% of the SOD III activity, which indicates that this SOD is Mn type. The optimum pH of the SOD III was 7.0 and the optimum temperature was $20^{\circ}C$. N-terminal amino acid sequence of purified SOD III was most similar to those of Psudomonase ovalis and Vibrio cholerae among bacteria.