• Journal of the Korea Concrete Institute
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• v.21 no.5
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• pp.565-572
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• 2009

In this study, corrosion resistance of palm oil fuel ash (POFA) concrete as a blended concrete is evaluated by using electrochemical technique. The POFA is an industrial byproduct obtained from fuel ash after extracting palm oil from palm-tree. In order to obtain basic material characteristics of the POFA concrete, tests on compressive strength, slump, weight loss, bleeding and expansion ratio were carried out the early-aged POFA concrete. On the other hand, durability characteristics, both chloride penetration and carbonation depth test, were also conducted. Finally, corrosion resistance were evaluated by applying electro-chemical artificial crack healing technique, and the tests on the impressed voltage characteristic, galvanic current and linear polarization resistance. From the experimental results, it was found that long-term strength, bleeding, lower slump ratio, expansion ratio, chloride penetration, carbonation and corrosion resistance were improved by using the POFA due to activated pozzolanic reaction. It can be also mentioned that POFA concrete has a potential to be used as a cementitious binder for green-recycling resources.

• Tunnel and Underground Space
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• v.27 no.4
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• pp.230-242
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• 2017

Seismic velocities measured from in-situ tests (n=177) and through rock core samples (n=1,035) are reviewed in light of construction standards, widely used standards as a first-hand approximation of rock classification solely based on seismic velocities. In-situ down hole tests and refraction survey for soft rocks showed seismic velocities of 1,400~2,900 m/s which is faster than those specified in construction standards. For moderate~ hard rocks, in-situ down hole tests and refraction survey showed 2,300~3,800 m/s which roughly corresponds with the range specified in the construction standards. A similar trend is also observed for seismic velocities measured from rock core samples. The observed differences between construction standards and seismic velocities can be explained in two ways. If construction standards are correct the observed differences may be explained with seismic velocities affected by underlying fast velocities and also possibly with selection of intact cores for velocity measurement. Alternatively, construction standards may have intrinsic problems, namely artificial discrete boundaries between soft rocks and moderate rocks, application of foreign standards without consideration of geologic setting and lack of independent verification steps. Therefore, we suggest a carefully designed verification studies from a test site. We also suggest that care must be exercised when applying construction standards for the interpretation and accessment of rock mass properties.

• Journal of Life Science
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• v.19 no.1
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• pp.87-93
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• 2009

We have investigated the effects of the culture broth of lactic acid bacteria (LAB) cultured in herb extract on growth, hematological parameter, nonspecific immune responses and disease resistance of olive flounder (Paralichthys olivacells) and parrot fish (Oplegnathus fasciatus) for 12 weeks. Weight gain of olive flounder fed diet with mixture was not significant among the control group. But In parrot fish, was significantly higher 20g than control group. The feed efficiency of olive flounder were 25% higher in the experimental groups than in the control. There were no significant differences in feed efficiency among each group on parrot fish. Treatment of olive flounder contents of GOT and GPT in serum decreased after 8 weeks. But there were no significant differences in GLU and TP among each group. Also, there was no significant of NBT reduction. The activities of lysozyme were higher in experimental group of olive flounder than in the control after 8 weeks. On the other hand, activities of lysozyme were triple higher in the experimental group of parrot fish than in the control after 12 weeks. In the oliver flounder case, the survival rate (%) after an artificial challenge with $10^7$ CFU/ml of Vibrio anguillarum and Streptococcus iniae per fish, was 18% higher in the experimental groups than the control. The higher survival rate of parrot fish were 17% and 16% in the experimental groups than the control respectively.

• Korean Journal of Ecology and Environment
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• v.50 no.3
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• pp.286-294
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• 2017

Development of transportation is rapidly reducing the barriers between countries, but this is causing the easier migration of species than the past. Typically, exotic species are imported for the purpose of food, leather, and pets. However, it has been introduced into the wild through artificially or naturally paths, and recently they are become a main cause of ecosystem disturbance. In this study, we investigated exotic turtle species introduced into the wild and analyzed their distribution characteristics. As a result of filed surveys, totally 4 genus 8 species 62 individuals of exotic turtles were found from 126 reservoirs in Gangwon-do and Gyeongsangnam-do, South Korea. In particular, Trachemys scripta elegans showed relatively high frequency than other turtle species and the natural reproduction of T. s. elegans was confirmed in some areas. On the other hand, the frequency of discovery of exotic turtles except T. s. elegans was relatively low, and the range of the areas was limited. Especially, exotic turtles except T. s. elegans were mainly found in public places such as reservoirs in the park. As a result of analyzing the distribution characteristics of exotic turtles using geographic information system, the turtles' distribution showed a high correlation with the artificial factor such as "urban". In this study, we identified the distribution characteristics of exotic turtles in the Korean wild, and these results will be important data for understanding status the and establishing effective management methods for exotic species.

• Journal of Embryo Transfer
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• v.25 no.4
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• pp.263-266
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• 2010

Prediction of semen's fertilizing ability used in artificial insemination (AI) is one of very important factors on pig reproductive performance. In vitro fertilization (IVF) has been used for indirect evaluation of sperm's fertilizing ability and it has been showed as highly correlated index. In swine industry, increasing interest in preservation of boar semen raises questions on the sperm motility from semen used in commercial AI centers. Mitochondria in sperm mid-piece generate the energy to support motility and could be an explanation of impaired fertility. Objective of this study was to suggest usable sperm motility to farms in measuring the effect of sperm motility and sperm abnormality on in vitro production of embryo in which sperm's fertilizing ability can be determined indirectly. Semen samples were provided from local AI center and used within 3 days after collection. Semen samples were divided by 4 different motile groups (>70%; 61~70%; 51~60%; <50%) using CASA (computer-assisted sperm analysis) on the days of IVF. Developmental rate to the blastocyst stage from over 61% motile sperm group showed significantly higher rate than below 60% motile sperm group ($16.5{\pm}0.7{\sim}18.4{\pm}0.8%$ vs $6.3{\pm}0.8{\sim}11.5{\pm}0.7%$, p<0.05). In experiment to determine the relationship between sperm motility and viability and abnormality, over 61% motile sperm groups showed significantly higher viability rate compared to below 60% motile sperm groups ($84.8{\pm}4.0{\sim}88.1{\pm}4.0%$ vs $69.1{\pm}4.0{\sim}74.2{\pm}4.0%$, p<0.05). On the other hand, morphological sperm abnormality showed significantly higher in over 70% motile sperm group ($10.2{\pm}2.2$ vs $16.0{\pm}2.2{\sim}21.0{\pm}2.2%$, p<0.05). In experiment to find the correlation between sperm motility of 4 different motile groups and amount of mitochondria, lower motility group also showed lower level of mitochondria (p<0.05). The mitochondria parameter used in this study showed another possibility to differentiate the sperm motility. Taken together, because below 60% motile semen used in AI reduce the fertility, AI centers should provide the over 60% motile sperm to the farms at the time of AI.

• Journal of Bio-Environment Control
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• v.12 no.3
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• pp.121-126
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• 2003

Tomato (Lycopersicon esculentum M. cv. ‘Momotarou’) and hot pepper seedlings (Capsicum annuum L. cv. 'Nockkwang')were grown under the 24h photopeliod (12 hrs light period: 12 hrs dark period) and 6 h photoperiod (3 hrs light period: 3hrs dark period). As a result of this experiment, the following details were observed. Plant height, leaf area, total dry weight, and leaf chlorophyll content decreased in case of tomato seedlings when they were given 6 h photoperiod. But the same effect was not observed in case of hot pepper seedlings. The photoperiod, however, did not produce any significant effect on the uptake of N, P, K, Mg and Ca ions in their nutrient solutions with the exception of their Fe. On thc 10th day of treatment, leaf chlorosis started to become visible in tomato seedlings and at the same time the uptake of Fe went down when the 6h photoperiod was applied to both tomato and hot pepper scedlings. In addition to this phenomenon, the sucrose content in leaf increased in case of tomato plants which were treated with 6 h photoperiod; on the other hand, their glucose content was observed to have decreased.

• Korean Journal of Plant Resources
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• v.12 no.2
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• pp.125-132
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• 1999

This study has investigated the growing features and vegetation of Acanthopanax chiisanensis and Acanthopanax koreanum in Mt. Jiri and Halla from Sep. 1997 to Aug. 1998. As to Acanthopanax chiisanensis, it occupied surrounding areas of Nogodan in Mt. Jiri of the height of 1,507m, ImgeolyoungJae of 1,300m and the Mt. Halla. of 1,100m of There were rather high constancy degree with Quercus mongolica, Schizandra chinensis, Hydrangen serrate for. acuminata, Acer pseudo-sieboldianum, Dryopteris crassirhizoma, Actaea asiatica, Thalictrum filamentosum, Abies koreana, Arundinella hirta from the sorts. The common species in Mt. Jiri and Halla are Acer pseudo-sieboldianum, Dryopteris crassirhizoma, Callicarpa japonica, Parthenocissus tricuspidata, Acer mono, Ligularia fischeri, Disporum smilacinum, Viola acuminata Aconitum kusnezofii. On the other hand, concerning of Acanthopanax koreanum community, it possessed the small areas of wedo weoltae village in Chejudo. In this area, a liana e.g. Dioscorea tenuipes, Hedera rhombea, Lygodium japonicum, Akebia quinata, Vitis thunbergii, Dunbaria villosa, Trachelospermum asiaticum var. intermedium, Vitis amurensis, Paederia scandens, lives with Pinux thunbergii, Celtis aurantiaca, Mallotus japonicus and so forth in tree layer and subtree layer. There is artificial change no move in the researching sites, Acanthopanax chiixanensis will be transformed into Abies koreana - Acanthopanax chiisanensis community. Soil characteristics showed the high value such as pH 6.56 and conductivity 0.258mmho/cm in Acanthopanax koreanum community of Mt. Jiri, they also indicated digit as follows: the content of organic matter and total nitrogen are from 25.16 through 25.35% and 7.58 through 9.30mg/g respectably. The soil characteristics at Acanthopanax chiisanensis community in Mt. Jiri and Halla, was high as like pH 5.76, conductivity 0.238mmho/cm, total nitrogen 9.30mg/g, total phosphorus 0.126mg/g in Mt. Halla.

• The International Journal of Costume Culture
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• v.4 no.1
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• pp.25-33
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• 2001

This study is to analyze Korean-Chinese women's Costume in Yabian with factors such as reform opening-up, economic growth, change of social values, development of technology, more education opportunities and influence of mass media. It divides the 1990's into two halves. Photos, interview, observation and relevant literature were used for this study. Even though economy grew rapidly, they needed to purchase daily goods other than clothes. In a way that they preferred practicality, it showed somewhat it was still developing. The trend in the first half of the 1990's was characterized : first, Synthetic or artificial fibers and ready-made suits were popular ; second, there still remained the men's style ; third, they wore Tanrikoo(彈力袴), Tisingkoo(體型袴), Jiaotakoo(脚袴) because of its properties of activeness and comfort ; fourth, shoulders looked ore prominent with pads as they were used in Chungsanfoo(中山服) ; fifth, clothes in grey and dark blue was in fashion ; sixth, they wore hand-made knit vests and sweaters and often mountain-climbing gears for its light and warm quality ; seventh, along with opening-up, various materials and colorful clothes were in style, which satisfied women's desire for beauty. They decorated Hanbok(韓服), using sleeves with colors, golden ornaments, flower patterns embroidery, materials of different color in collar and tie and dyes of sleeves and skirts. In the first half of the 1990's when the opening-up was beginning, there were diverse styles and colors in fashion, yet not close to good quality. As the economy grew, the second half of the 1990's was characterized by good palate, individuality, favouritism on foreign goods, rapid change of fashion. For instance, fur coat and woolen fabric were favored. Economic growth led to abundance of cloth, dyes and decorative materials. In addition, people possessed more clothing and it was possible for them to wear both Hanbok and wedding dress in wedding ceremony. People placed their standards on competency and financial ability rather than ideology. Worship disappeared and individuality arose. Therefore, apparel functioned not only as protection but as suits with aesthetic purpose. This resulted in introduction of bold style, imitation of western countries and extension of use of Hanbok. With the help of mass media, transportation, telecommunication, contact with Korean company and civilians, Korean and western cultures, through Korea, were accepted. Change in structure of economic status caused excessive spending and more educational opportunities that enabled people to accept foreign culture quickly. Values moved onto new, beautiful and better characteristics. it was possible to have suits ready-made due to improvement of mass production and cotten, wool, linen, silk became popular owing to technology. New technology, the bases of mass consumption, increased possession of clothing and accelerated change of fashion. In summary, women's Costume in Yanbian were affected by the factors in economy, politics, culture contact as well as change of society and technology.

• Journal of Conservation Science
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• v.31 no.2
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• pp.87-94
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• 2015

Plastic artwork can be appeared crack, change of color and whitening event by various environment conditions. A large scale plastic artwork often exhibits in outside it will be directly degraded by physical and chemical degradation factor such as strong sunlight, high humidity and rainfall. We should know degradation characteristic of plastics to prevent these damages. In this study, we studied degradation characteristic of plastics (5 types of wide use plastics; polypropylene, polystyrene, polyethylene, polyvinyl chloride, polyurethane) depending on various artificial degradation conditions such as high temperature, ultraviolet and these complex conditions (high temperature and ultraviolet). As a result, polypropylene, polystyrene and polyethylene show the most visible change especially polypropylene, polystyrene. Polypropylene didn't show a great change degree of tensile strength and contact angle, on the other hand polystyrene did. Polypropylene and polystyrene weakened by photo degradation, polyvinyl chloride and polyurethane had relatively good light stability. Also the high temperature and complex conditions were most degradation characteristic. High temperature worked for degradation catalyst because its energy can not enough worked for cut off binding energy of plastics while ultraviolet condition effected as directly degradation condition. Though following results, we expect it can be applied to investigation of degradation factor depending on plastic artwork materials and basic result of plastic artworks conservation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.232-237
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• 1999

The relationship between structure and contractile activity was studied on the three neuropeptide $\gamma$ (mammalian-, bowfin-, shark-NP$\gamma$) that were synthesized by the solid-phase method. Circular dichroism spectra showed that mammalian-, bowfin- and shark-neuropeptide $\gamma$ took an unordered structure in buffer solution and artificial liposome. The intestinal motility response was investigated with guinea-pig ileum, rat duodenum and carp intestine. In case of carp intestine, contractile activity was as follows; bowfin-NP$\gamma$> shark-NP$\gamma$>mammalian-NP$\gamma$, On the other hand, the contractile activity of mammalian-neuropeptide $\gamma$ was more potent than those of bowfin-, shark-neuropeptide $\gamma$ in the guinea-pig ileum and rat duodenum. These results suggest that NP$\gamma$ show the species-specific activity.