• Korean Journal of Ichthyology
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• v.9 no.1
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• pp.48-60
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• 1997

The species composition and seasonal variations of fish community in the Zostera marina belt at the coastal water off Hamduck, northern part of Cheju Island, were analyzed based on day and night samples collected by a small beam trawl from May 1993 to May 1994. The dominant species among the 58 fish species in 35 family were tubesnout, Aulichthys japonicus, gobie, Pterogobius zonoleucus, filefish, Rudarius ercodes, pipefish, Syngnathus schlegeli and sea catfish, Plotosus lineatus. These species comprised 86.1% in the number of individuals and 62% in biomass. The number of individuals and biomass were high between October and December, and low between January and April. About 90% of fishes were noncommercial and small-sized fishes, less than 14cm in total length. The larvae and juvenile fishes were collected in the study area throughout the year. The recruitments of dominant species were related to the seasonal variations of Z. marina utilized as a shelter or feeding ground. A japonicus, P. zonoleucus, Zoarchias glaber and Hexagrammos agrammus recruited between January and June, and R. ercodes, S. schlegeli, P. lineatus and Petroscirtes breviceps between July and December.

• Korean journal of applied entomology
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• v.42 no.2
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• pp.145-152
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• 2003

Field application of the entomopathogenic nematode, Steinernema carpncapsae, is limited by its susceptibility to UV irradiation and desiccation especially at leaf spray control. This study was conducted to develop the control technique using alginate biocapsulation of the nematodes against the beet armyworm, Spodoprera exigua and the tobacco cutworm, Sp. litura that are normally infesting hosts above ground level. The alginate capsules including infective juveniles gave significant feeding toxicities to the larvae of the two lepidopteran species. The lethality followed a typical sigmoid dose-mortality pattern with increase of the nematode densities embedded in the capsules. Moisture content in the capsule was critical to the survival of the infective juveniles. More than 80% nematodes could survive above 10% moisture content remained in the capsule. Remaining moisture content within the capsule was dependent on relative humidity, ambient temperature, and capsule size, but not on citric acid reaction time during capsule formation. More than 80% of infective juveniles in the alginate capsules could survive in distilled water at 15$^{\circ}C$ for 60 days. When these nematode capsules containing welsh onion extract as another phagostimulant were applied on the 3rd instar larvae of Sp. exigua infesting peanut plants, they resulted in about 90% control efficacy. These results indicate that the alginate capsulation can be used for leaf-spray agent of the entomopathogenic nematodes as well as for improved storage purpose.

• Journal of Aquaculture
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• v.16 no.4
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• pp.257-261
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• 2003

The effects of different stocking densities on the growth of juvenile abalone, Haliotis discus hannai and water quality in the recirculating system with rotating biological contactor, were assessed. The trials were conducted using total weight 32 g juveniles abalone for 60 days at stocking densities of 5, 10, 15 kg/$m^2$. The animals were fed sufficient amounts of the pellet diet of 30.4% protein during the experimental period. Daily feeding rate (DFR) and survival rate (SR) of 5 kg/$m^2$ showed 0.76% and 85.5% those were not significantly differed 10 kg/$m^2$ showing 0.75% and 96.0% (P>0.05). DFR and SR of 15 kg/$m^2$ showing 0.38% and 31.2% were significantly lower than 5 and 10 kg/m2 (P<0.05). Daily growth rate (DGR) and feed efficiency (FE) showed the highest as 0.19% and 24.2% in 5 kg/$m^2$ the lowest as 0.05% and 14.3% in 15 kg/$m^2$ (P<0.05). According to, these results was an inverse relationship between growth and stocking density. The optimum density of juvenile abalone from this experiment is 5 to 10 kg/$m^2$ in the recirculating system.

• Resources Recycling
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• v.16 no.5
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• pp.19-24
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• 2007

Reefs are the marine structure that can give resting, inhabiting, feeding and nursing spaces for a variety of fishes. Usually artificial reefs are made of cement and steels respectively in Japan as well as in Korea. However since resources deficiency has been getting serious, other materials are taken into consideration for the basic bodies of artificial reefs. About 300 thousand tons of waste agricultural plastic films are generated every yew in Korea, but no effective recycling techniques have been developed. In this sense, artificial reefs made of waste agricultural plastic films are the most representative symbol of the recycled products in the Resource Recycling Era. In particular, since these reefs could be made of the semi-cleaned waste agricultural plastic films that still contain high portion of soil, it is very environmentally friendly not only in manufacturing process but also in using under water. Furthermore they have some evident advantages as follows; 1) high fish swarming effect 2) good initial attachment of the marine growths 3) extremely low corrosion to brine 4) easy adjustment of the gravity 5) economical manufacture, transportation and jettison 6) excellent safety to ecosystem caused by lower elution of toxic substances 7) good recyclable property after application and so on.

• Food Science and Preservation
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• v.13 no.5
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• pp.629-633
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• 2006

Pinus rigida Miller leaf extract (PRLE) showed antimicrobial activity remarkably against food pathogenic and spoilage bacteria at concentrations of $100{\sim}250{\mu}g/mL$. Alcohol-soluble PRLE had higher antimicrobial activity against Staphylococcus aureus and E-coli than any other-soluble PRLE such as butanol, ethyl acetate, ether and water. As PRLE concentration increased alcohol-soluble PRLE increased the remarkable inhibitory zone of microbial growth on the microbial media. PRLE showed good stability against temperature and pH in the range of $40{\sim}150^{\circ}C$ and $4{\sim}11$, respectively. This may indicate that PRLE can be a potential anti-microbial agent for industrial application. In addition, SEM of Listeria monocytogenes suggested that it antimicrobial component would perturb the functions of microbial cell membranes synergistically. In the feeding experiment the formaldehyde content in the serum of formalin-fed and PRLE-treated me decreased remarkably due to the lysis of formaldehyde and the rate of hemoglobin biosynthesis was recovered to the orignal state within a short breeding time.

• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.605-614
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• 2020

This study was conducted to compare the growth performances of three groups of commercial Korean native chickens (KNCs) including two strains of crossbreeds and H3 (Hanhyeop 3) from hatch to twelve weeks of age. (1A, 2A, and H3). A total of 468 one-day-old chicks were allocated in a completely randomized design with 15 replicates per treatment for the crossbreeds and 9 replicates per treatment for H3 (12 birds per cage). Commercial broiler diets (i.e., Week 0 - 5 crude protein [CP] 22.0%, metabolizable energy [ME] 3,025 kcal·kg^-1; week 5 - 8 CP 20.0%, ME 3,100 kcal·kg^-1; week 8 - 12 CP 19.0%, ME 3,150 kcal·kg^-1) were provided according to the Korean Feeding Standard for Poultry on an ad-libitum basis with fresh clean water during the twelve-week period. Body weight gain and shank length (SL) were measured weekly until week 6 and bi-weekly during week 6 to 12. Compared to H3, the two crossbreed groups had a higher body weight (BW) on weeks 3 to 8; however, the bodyweight of H3 on week 10 was significantly higher than the other groups (p < 0.05). Moreover, the average daily feed intake (ADFI) of H3 was higher than that of the two crossbreed groups from hatching to 84 days except for week 3, and H3 showed a lower average daily gain (ADG) on weeks 3 and 10 (p < 0.05). Furthermore, H3 had a higher feed conversion ratio compared to another crossbreed chicken on weeks 1 to 8 and the last week after hatching. Among all the groups, there was no significant difference for shank length during the experimental period.

• Korean Journal of Food Science and Technology
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• v.19 no.1
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• pp.61-65
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• 1987

The milk protein portion contains sialic acid which may be used as an index for k-casein. In comparison with non fat dry milk (NFDM) and calcium caseinate, the solubility of NFDM protein isolates at the various pH was inferior. Another consideration for the low solubility relates to the possibility that k-casein may have been extracted or possibly modified by the action of alcohol. The k-casein is the principal stabilizing fraction for casein micelle and any changes which result in its destruction or removal would be expected to have potent results. During solvent treatment, 16.5% of sialic acid was extracted in the first extraction solvent, whereas the second treatment caused only a 4.0% loss, based on sialic acid analysis. A study was conducted on the effect of concentration of methanol on loss of sialic acid. The loss of sialic acid decreased as the concentration of methanol increased to above 62% in both the first and second extracted solvent. It appears that loss of sialic acid is attributed to the water fraction rather than the methanol fraction. The effect of addition of the dried extracted solids on solubility was investigated. Protein solubility of NFDM protein isolates was sharply increased by 10% addition of the extracted solids and, thereafter, decreased. Efforts to restore solubility by feeding-back the extracted material supported the concept that removal of surface k-casein may have been a possible factor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.748-757
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• 2007

This paper is intended to solve the technical problem that fails in large-capacity induction motor starting due to serious voltage drop during starting period. One induction motor that is established already can reach in steady-state using reactor starting method but the voltage magnitude of PCC (point of common coupling) has dropped down a little. When the same capacity induction motor is installed additionally in the PCC, where the existing induction motor is operating, voltage drop becomes more serious by starting of additional induction motor. As a result, the additional induction motor fails in starting. Therefore, voltage compensation method is proposed so that all of two induction motors can be started completely. First, modeling technique is described in order to implement starting characteristics of large induction motor. And then, this paper proposes strategic starting scheme by proper voltage compensation that use no-load transformer tap control (NLTC) and step voltage regulator (SVR) for starting of two large induction motors successfully and improving the feeding network voltage profile during the starting period. The induction motor discussed in this paper is the pumped induction motor of 2500kVA capacity that is operating by KOWACO (Korea Water Resources Corporation). Modeling and simulation is conducted using PSCAD/EMTDC software.

• Resources Recycling
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• v.22 no.6
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• pp.64-72
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• 2013

The purpose of this study is to confirm the possibility of obtaining high grade coal from 57.39% of fixed carbon fine coal. Also, the mineralogical, physical/chemical and liberation characteristics are to be identified to decrease in ash amount, during the pre-processing of clean coal technology. In this study, batch flotation and CPT column flotation proper for the processing of fine particles were used with the variation in kinds and quantity of frother, collector and depressant. Also air flow rate and feeding rates were examined. As a result of batch flotation using 20% of pulp density DMU 101 collector(100 mL/ton), AF65 frother(300 mL/ton), sodium metaphosphate depressant (1 kg/ton), 67.57% of ash rejection and 70.90% of combustible recovery were obtained. The result of CPT column flotation was 85.59% of ash rejection and 88.97% of combustible recovery under the conditions of 5% of pulp density, DMU-101 collector (100 mL/ton), AF65 frother(10 L/ton), SMP depressant(1 kg/ton), wash water(100 mL/min.) and air flow rate(1,200 mL/min.).

• Korean Journal of Poultry Science
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• v.32 no.4
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• pp.269-273
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• 2005

The wild ginseng culture by-products(WGCB) was added to the laying hens diets. A total of 420 Lohmann Brown laying hens were alloted to five levels of drinking water containing WGCB 0, 0.4, 0.8 1.6, $3.2\%$with seven replications and fed com-soybean meal based diets contained ME 2,800 kcal/kg, CP $16\%$. Laying Performance, egg quality, egg yolk fatty acid and cholesterol concentration were measured. Egg Production and daily e99 mass were significantly lower(p<0.05) in birds fed the WGCB $3.2\%$ compared with no WGCB group, but showed no significant effect in other treatments. Feed efficiency of birds fed $0.4\%$ WGCB showed the lowest of all treatments(p<0.05). Eggshell thickness was increased(p<0.05) by WGCB supplementation, whereas eggshell breaking strength, haugh unit and yolk color index were not affected. No significant change in yolk fatty acids and cholesterol were observed by the addition of WGCB.