• Korean Journal of Ichthyology
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• 제8권1호
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• pp.83-89
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• 1996

The early life history of Korean bullhead, Pseudobagrus fulvidraco was studied to obtain some information required in aquaculture and reinforcement of natural population. The fertilized eggs were almost spherical in shape and demersal. The egg membranes were transparent with minute folds on the surface, causing them to stick to other substrates. Yolk is yellowish without oil droplets. The eggs just after fertilization were measuring $1.4{\pm}0.03mm$(1.3~1.5mm, n=10) and expanded to $1.7{\pm}0.08mm$(1.6~1.8mm, n=10) in diameter in 1.5 hr. The blastodisc was formed in 30 min and cleavage started in 1 hr after fertilization, and the intervals of each stage of cleavage was about 30 min at $25.0^{\circ}C$. The yolk from 32-cell stage to gastrula stage partly depressed and the depressed part moved clockwise. Hatching occurred in 53 hr after fertilization and hatched embryos had 18~19+20~21(38~40) myomeres measuring 4.2~4.3mm in total length. At the age 7 d after hatching, 4 pairs of barbels were already formed ; 1 pair on the posterior part of the nostril, 1 pair on the upper jaw, and 2 pairs on the lower jaw. And the posterior margin of caudal fin changed into two folds. The lateral band and the form of all fins were completed in 3 weeks.

• Composites Research
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• 제31권5호
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• pp.209-214
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• 2018

This paper explain about the development of environmental friendly, low cost and stable supply material i.e., rice husk and shell were used as micro incorporating bio waste filler. Those were processed by ball mill and analyzed through micro observation by FE-SEM, EDS and particle size distribution. The obtained filler was mixed with epoxy resin for the manufacturing of CFRP composite and study tensile properties. In EDS analysis main contents of rice husk and rice husk ash are C, O and Si. When rice husk was burned C and Si ration were increased. Shell powder has C, O and Ca. It caused $CaCO_3$ from shell. Surface weighted mean of rice husk powder is $6.19{\mu}m$ and volume weighted mean is $14.77{\mu}m$. And it has rod type particles which caused hair and husk structure parts. Surface weighted mean of rice husk ash powder is $1.55{\mu}m$ and volume weighted means is $8.20{\mu}m$. Surface weighted mean of shell powder is $2.53{\mu}m$ and volume weighted mean is $5.79{\mu}m$. The tensile decreased with increasing the content of micro filler in CFRP composites. In case of rice husk, the significant decrement of tensile strength was observed. and in case of shell powder, there is no effect of changes take place in tensile strength.

• Korean Journal of Plant Resources
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• 제27권5호
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• pp.534-539
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• 2014

This study was carried out to establish seed propagation method of Hydrangea petiolaris Siebold & Zucc., one of the specific and protected plant species for the floral region. Seed size ranged $1.36{\times}0.84mm$, weight of thousand seeds was $2.3{\pm}0.02mg$. Observation of seed morphology characters showed wrinkled surface and elliptical shape, indicating amber color and fine seeds. Moisture contents of seeds, increased rapidly by water-soaking treatment, recording maximum moisture contents (31.9%) after 48 hours. Percent germination of seeds was higher under the light than dark condition. Seed germination was the best at $25^{\circ}C$ under the light condition (78.0%) among temperature and light conditions treated. Percent germination, germination energy and $T_{50}$ was greatly improved by soaking in $GA_3$ solutions for 48 hours. Especially, $100{\sim}500mg{\cdot}L^{-1}$ $GA_3$ treatment resulted in the highest germination rate as 90.0% and above.

• Journal of the Society of Cosmetic Scientists of Korea
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• 제32권1호
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• pp.35-44
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• 2006

Recently, encapsulation studies have been tarried out to protect active agents using shell materials such as polymers, lipids, inorganic materials and the other protective materials. We have prepared copolymers of methylmethacrylate (MMA) and trimethoxysilylpropylmethacrylate (TMPMA), and the copolymers as shell materials were used for encapsulating active agents. Poly(MMA-co-TMPMA) spheres were very efficient for encapsulating active agents such as vitamin derivatives (such as retinol, retinyl palmitate, tocopheryl acetate and ascorbyl tetraisopalmitate) and oil soluble licorice extract etc. Mean diameters of poly(MMA-co-TMPMA) core-shell spheres containing active agents varied between about 0.1 to $10{\mu}m$ according to the experimental conditions. The loading amount of encapsulating active agents was 15 to 25% (w/w) and the loading yield was above 90%. The stability of active agents in poly(MMA-co-TMPMA) core-shell spheres prepared with an UV absorbing precursor increased by 25% compared with that of active agents in spheres prepared without an UV absorbing precursor.

• Korean Journal of Environmental Biology
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• 제18권4호
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• pp.377-385
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• 2000

This study was carried out to investigate the ecotoxicological response on Gammarus sobaegensis Ueno with acid stress. Mean value of $LT_{50}$ (lethal time 50%) under pH 3 condition as acute ecotoxicity test was observed to be 0.271 ($\pm$0.146) day. And 0.812 ($\pm$0.377) day under pH 4, respectively. Mean value of $LT_{50}$ under pH 3 and 5 were 6.313 ($\pm$0.828), and 9.475 ($\pm$4.881) day, respectively. Variance in chronic ecotoxicity test pH (F ratio: 11.240, P< 0.0005) and times (F ratio: 2.916, P< 0.0005) as single factor were revealed to be the major factor for determining LT$_{50}$ with acid depression. The variation of secondary gill surface with acid stress to be certain that wrinkle phenomenon. Being weak tolerance of G. sobaegensis against the acid stress, it shows the possibility to be examined as an aquatic toxicity test organism.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제37권10호
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• pp.1201-1206
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• 2013

Defects that occur during the manufacturing process or operation of a wind turbine blade have a great influence on its life and safety. Typically, defects such as delamination, pore, wrinkle and matrix crack are found in a blade. In this study, the detectability of the pores, a type of defect that frequently occur during manufacturing, was examined from the full field strain distribution determined with the image correlation technique. Pore defects were artificially introduced in four-ply laminated GFRP composites with $0^{\circ}/{\pm}45^{\circ}$ fiber direction. The artificial pores were introduced in consideration of their size and location. Three different-sized pores with diameter of 1, 2 and 3 mm were located on the top and bottom surface and embedded. By applying static loads of 0-200 MPa, the strain distributions over the specimen with the pore defects were determined using image correlation technique. It was found the pores with diameter exceeding 2 mm can be detected in diameter.

• Korean Journal of Medicinal Crop Science
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• 제12권1호
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• pp.67-72
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• 2004

For discrimination the origins and the commercial herb medicines of three Angelicae Radixes (Danggui), anatomical characters of leaves, petioles, and root cross-section were investigated and those were compared each other. The key for discrimination of these herb medicines was made by below simple characters: development of periderm, absent and present of collenchyma under the periderm, and distribution of latex tube in cortex. The result of discrimination for the commercial herb medicines based on the discrimination key, Angelicae gjgantis Radix (Angelica Gigas Root), Angelicae Radix (Japanese Angelica Root), and Radix Angelicae Sinensis (Danggui) were correctly identified for Angelica gigas Nakai, A acutiloba Kitagawa, and Angelica sinensis (Oliv.) Diels., respectively. Consequently, anatomical characters could be utilized for useful method to discriminate three Angelicae Radixes (Danggui).

• The Korean Journal of Mycology
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• 제42권2호
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• pp.165-169
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• 2014

In this study, we measured antioxidant activity as DPPH radical scavenging and the total polyphenol content of pulverized and lyophilized oak pollens inoculated with fungi to confirm the husk removal effect. The total polyphenol content of oak pollen was highest in lyophilized pollen medium inoculated with Armillaria mellea, and was lowest in pollen inoculated with Lentinula edodes. Total polyphenol content of the lyophilized pollen was higher than that of the refined pollen and the pulverized pollen in oak pollen germinated with A. mellea. The total polyphenol content of the lyophilized oak pollen germinated with A. mellea was 1.4-fold higher than that extracted with water. Measurement of antioxidant activity using the DPPH (2, 2 diphenyl-1-picrylhydrazyl) free radical scavenging method showed that the lyophilized oak pollen germinated with A. mellea had the highest and that germinated with L. edodes was lowest in antioxidant activities. The lyophilized oak pollen germinated with A. mellea was 2 to 4 times higher than that extracted with water in the antioxidant activity of DPPH free radical scavenging. Many germinated cells were formed around pore of acorn pollen inoculated with L. edodes, while those were formed at the end of hyphae derived from oak pollen inoculated with A. mellea.

• Journal of the Korean Society of Food Science and Nutrition
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• 제25권5호
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• pp.796-803
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• 1996

Gamma irradiation was applied to soybean(Glycine max.), Hwangkeum, at dose levels of 0, 5, 10 and 20 kGy to improve the physical properties of soybeans. The time to reach a fixed moisture content was reduced depending on the increment of soaking temperatures and applied irradiation dose levels. Irradiation at 5~20 kGy resulted in reduction in soaking time of the soybeans by about 3~6 hrs at soaking temperature of $20^{\circ}C.$ The degree of cooking of soybeans in boiling water was determined by measuring the maximum cutting force of cotyledon. The cutting force to reach complete cooking was about 145g/g. Irradiation at 5~20 kGy resulted in a reduction of cooking time of soybeans by 55~75% as compared to the nonirradiated soybean. In electron microscopic observation of seed coat inner, the parenchyma of nonirradiated soybean showed tight fibrillar structure, whereas that of irradiated soybeans showed loosened and deformed structure. The microstructure of compressed cells and cotyledon epidermis was also deformed by gamma irradiation. In subcellular structure of cotyledon, the roundness of protein body was deformed and changed to spike shape at 20 kGy. Also, the size of lipid body decreased as the irradiation dose levels increased.

• Journal of Korean Society of Forest Science
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• 제89권3호
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• pp.389-396
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• 2000

To determine whether the Tricholoma matsutake (pine mushroom, Songyi) is symbiotic or parasitic to Pinus densiflora, structural change in their natural ectomycorrhizas were examined. The mycorrhizal samples were collected at three progressional points in the natural hypogeous colony(shiro) : colony front edge, near the fruiting point and 20cm back. The fine roots in the colonies were typical ectomycorrhizas with fungal mantle and Hartig net. However, the T. matsutake mycorrhizas had unique characteristics compared to other types of ectomycorrhizas. That is, spatially the fungal mantle and Hartig net of the T. matsutake mycorrhizas continued to develop along the growing tip, while temporally those structures declined to shrink changing to black brown in the older part of the roots behind the actively growing tip portion. However, there was no mark that the fungal hyphae penetrated into either the cortical cells, endodermal cell layers or stele. The apical tips of the blackened roots remained alive to form new mycorrhizas with other fungi later. Therefore, we conclude that the mycorrhiza of T. matsutake+P. densiflora is rather a dynamic symbiosis that changes its position spatiotemporally as the root grows than either a simple parasitism or symbiosis.