• International Journal of Highway Engineering
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• v.4 no.1 s.11
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• pp.149-159
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• 2002

This study was performed to estimate the high-speed direct tensile strength(DTS1), low-speed direct tensile strength(DTS2) , indirect tensile strength(ITS) resilient modulus(MR) and stiffness index(SI) of sand asphalt mixture based on the absolute viscosity, kinematic viscosity, penetration, softening point and PG grade of binder. DTS2 showed higher correlation with the physical properties than other properties of mixture, and the next was DTS1, ITS, SI and MR in order. Among binder properties, PG grade showed the highest relation with DTS2. Therefore. it was found that the high DTS mixture could be made when the binder with a high PG grade was used. However, since the individual physical property showed a relatively low correlation, various properties were used together in regression analysis. The estimation models of DTS and ITS were over 0.99, respectively. R2 of MR and SI estimation models were over 0.91 and 0.93, respectively. It was concluded that mechanical properties could be estimated with a high coefficient of determination from those physical properties.

• Korean Journal of Environment and Ecology
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• v.35 no.6
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• pp.579-593
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• 2021

In order to understand the types of vegetation in warm temperate-climate zones, vegetation was investigated in several island areas in Jeollanam-do (Jindo, Wando, Gangjin, Goheung, and Yeosu). The evaluation standard for degraded level of warm temperate forests were proposed based on the importance percentage (IP) in canopy layer of the evergreen broad-leaf forests and the number of arboreal evergreen broad-leaf species. Through these measurements, the restoration types and techniques for each degraded level were estimated, and it is intended to be used in establishing restoration plans for the southwest coast island area. The vegetation was analyzed using the two-way indicator species analysis (TWINSPAN) method using survey data of 307 plots. As a result, it was divided into 8 communities, and the appearance characteristics of evergreen broad-leaf species were identified in each community. Community I was located on the lower slope at an altitude of 86.6 m, and Neolitsea sericea and Castanopsis sieboldii were dominant. Communities II and III were the vegetation types that appear on the coast below an altitude of 10.5 to 22.5 m, and Machilus thunbergii, Cinnamomum japonicum, N. sericea, and C. sieboldii were dominant. Communities IV and V were vegetation types that appeared in the lower and middle slops between the altitudes of 71.9 to 153.4m, and C. sieboldii was dominant. In community VI, the N. sericea was dominant in the lower and middle slops at an altitude of 166.9 m. The last communities VII and VIII were the vegetation types that appeared on the middle slop at an altitude of 187.8 to 246.2 m. Also, Quercus acuta and Q. salicina were present. In summary, the evergreen broad-leaf forests dominated by M. thunbergii, C. japonicum, and N. sericea appeared mainly in the coastal areas of the lowlands. The community of C. sieboldii was distributed higher inland than this community. The communities that appeared mainly in the inland highlands at levels above these two communities were Q. acuta and Q. salicina. The degraded level was classified as 0 to V, according to the IP of arboreal evergreen broad-leaf species and the number of arboreal evergreen broad-leaf species. According to the degraded level, the restoration types (preservation, induction, improvement, creation) and the restoration techniques were determined.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.422-439
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• 2014

In this study, we measured the effects of UV protection efficiency of the polarity of oil, the type of emulsion, the viscosity of product, the type of thickener and light stabilizer in sunscreen. As a result, even higher polarity of the oil, UV protection efficiency is measured high (Butyloctyl salicylate: SPF 44.10, PA 7.93). In case of low, it was measured low conversely (Dimethicone: SPF 16.40, PA 5.57). In case of emulsion types, UV protection efficiency of W/O emulsion which organic sunscreen agent is based in the outer phase is measured higher than O/W emulsion. According to increasing of viscosity, UV protection efficiency tends to increase proportionally. However, the size of emulsion particles and the kinds of thickener has no effect to UV protection efficiency. Also light stabilizer was found to be an important factor affecting the UV protection efficiency. As a result, it is able to improve UV protection efficiency and it has potential which improve the economical effect of the sunscreen without increasing sunscreen agents.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2000.05a
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• pp.5-7
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• 2000

국내에서의 식이섬유의 이용은 대부분 저분자량의 수용성 식이섬유를 이용한 음료형태가 주류를 이루고 있으며, 밀기울, 귀리, 옥수수 껍질 등으로 부터 얻는 불용성 식이섬유는 제과 및 제빵등에 이용되어 오고 있다. 수용성 식이섬유는 혈중 콜레스테롤을 저하시키며, 불용성 식이섬유는 변비예방과 장기능 증진효과가 탁월한 것으로 알려져 있다. 그러므로, 대장암과 변비같은 장질환 환자가 날로 증가하고 있는 상황에서 국내산 미이용 자원으로부터 불용성 식이섬유의 기능성 향상과 활용기술을 개발하는 것은 식품산업적 가치가 크다고 할 수 있다. 또한, 국내에서 소비되고 있는 폴리덱스트로스와 올리고당과 같은 기능성 당류의 대부분이 외국에서 수입하여 국내에 보급되고 있기 때문에 큰 외화지출이 되고 있다. 따라서 본고에서는 국내산 미곡 부산물인 밀기울 식이섬유 세포벽의 불용성 구조를 수용성으로 변화시킬 수 있는 변형기술과 얻어진 수용성 식이섬유 소재의 특성을 소개하고자 한다. 즉, 밀기울 세포벽의 수용화를 위한 가공처리는 압출성형 공정에 의하여 실시하였으며, 수용화가 수반되는 압출성형 조건에 따른 식이섬유 소재의 이화학적 특성과 수용화가 일어난 세포벽 성분의 분해기작에 대한 연구결과를 정리하였다. 그리고, 현행 올리고당과 식이섬유의 산업적 생산공정에서 문제점으로 대두되고 있는 효소처리, 산성하에서의 감압가열, 고점도 원료물질의 이송, 생물공학적 공정제어, 반응시간, 잔여 효소의 불활성화 및 재활용, 제조원가 상승 등과 같은 것을 해결하거나 개선할 수 있는 효율적인 압출반응공정의 조건과 생산된 소재 glucooligosaccharide, fructooligosaccharide, galactooligosaccharide 등의 특성에 대하여 논하여 보기로 한다.경우가 많지 않다. 또한 그 발생 경위나 원인요소에 대해서는 일반에게 공개되지 않고 있어, 우리가 실천하여 식중독을 예방할 수 있는 정보가 함께 제시되지 못하는 형편이다. 따라서 본 고에서는 최근 수년간 외국에서 학교급식을 비롯한 집단급식 등에서 발생한 식중독 사례를 중심으로 고찰, 분석하였다. 이로부터 식중독 발생에 기여한 주요 원인을 찾아내고 여기서 얻어지는 교훈을 토대로 식중독 발생을 예방 및 최소화할 수 있는 실천적 대처 방안을 모색해 보고자 한다.중의 E. coli O157:H7이 연관되어있다는 보고도 있다. 목장 방문시 원유를 마신 어린이에서 HUS가 유발하였고, 균분리 결과, 농장의 소와 어린이에서 유사한 E. coli O157:H7이 분리된 바 있다. 본 연자들은 베로톡신 유형, plasmid profiles, RFLP 분석, phage type을 기초로하여 소에서 분리된 E. coli O157:H7이 사람유래주와 매우 유사함을 확인하였다.mm 및 2-6mm 난포에서의 101개(67.8%) 및 47개(50.0%) 보다 매우 낮게 나타났다. 전체 회수 난포란수도 4등급이 59.1%(149/252)로써 1, 2, 3등급의 0.4% (1/252), 7.6%(19/252) 및 32.9%(83/252)보다 높게 나타났다. 1회 평균 회수 난포란은 $\leq$2mm 난포에서 4.8$\pm$3.7개로써 2-6mm(3.0$\pm$3.4개) 및 $\geq$6mm (0.3$\pm$0.6개)보다 높았으며, 1회당 평균 8.1$\pm$5.1개의 난포란을 회수하였다. investigation can be separated into sa

• Korean Journal of Food Science and Technology
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• v.14 no.1
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• pp.63-66
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• 1982

The pectin content in tangerine peel and the characteristics of extracted pectin and its gel were determined. The pectin contents of citrus peel and citrus albedo were 11.52% and 9.3% on a dry weight basis, respectively The equivalent weight, methoxyl content and acetyl content of the extracted citrus peel pectin were 596, 13.41% and 0.125% respectively. The intrinsic viscosity and molecular weight of extracted citrus peel pectin were higher than those of commercial citrus pectin samples. The anhydrouronic acid content and jelly grade of the extracted pectins were 98.4% and 138.1, respectively. These were higher than those of commercial citrus pectin. In the textural characteristics of gels, the gel made from the extracted pectin was shown to have lower values in hardness, cohesiveness, adhesiveness and gumminess than the gels made from commercial citrus pectins.

• Korean Journal of Environment and Ecology
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• v.31 no.6
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• pp.508-519
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• 2017

There have been many studies on monitoring of biodiversity changes and preservation of Gwangneung Forest Biosphere Reserve (GFBR) in South Korea in recognition of the rare ecosystem that has been preserved for a long period. However, there are few studies on diversity and community characteristics of benthic macroinvertebrates as an indicator of stream health of GFBR. The purpose of this study was to assess the water quality of Bongseonsa Stream that penetrated through Gwangneung Forest and the nearby torrents by analyzing the benthic macroinvertebrates community during April to September 2016. The investigation collected a total of 114 species of benthic macroinvertebrates belonging to 56 families, 17 orders, 8 classes, and 5 phyla from the Bongseonsa Stream and Kwangneung Stream. Ephemeroptera and Trichoptera were the largest groups in species diversity with 30 species (32.3%) and 16 species (17.2%), respectively, and Tubificidae sp., Baetis fuscatus, Antocha KUa, and Cheumatopsyche brevilineata, which usually habit in contaminated streams, appeared frequently. Among the feeding function groups, the gatherers and hunters appeared relatively frequently, and the shredders and scrapers appeared frequently in the torrents. Among the habitat oriented groups, the clingers and burrower appeared more frequently and represented the microhabitats in the shallow areas. The result of the analysis of benthic macroinvertebrates community showed that the dominant index was $0.48{\pm}0.10$ in average while it was lowest with 0.33 in GS 8 of the Gwangneung Forest torrent and highest in BS 1 of Bongseonsa Stream. The diversity and richness indices were inversely proportional to the dominant index and were 2.53 and 4.22, respectively, in GS 8 where the dominant index was low. The result of the analysis of community stability showed that area I, which had high resistance and restoration, was high in Bongseonsa Stream while the area III, which had low resistance and restoration, was high in Gwangneung Forest, indicating that the water system in Gwangneung Forest had a wider distribution of specifies sensitive to agitation. The biological water quality assessment showed ESB of $50.88{\pm}17.69$, KSI of $1.11{\pm}0.57$, and BMI of $78.55{\pm}11.05$. GS 8 of Gwangneung Forest torrent was judged to be the highest priority protective water area with the best water environment and I class water quality with ESB of 63, KSI of 0.55, and BMI of 89.9. On the contrary, BS 1 of Bongseonsa Stream was judged to be the high priority improvement area that had the lowest water quality rating of III with ESB of 25, KSI of 2.13, and BMI of 62.7. Although the diversity of water beetle was higher in the water system of nearby Bongseonsa Stream than the water system inside the Gwangneung Forest, the annual community structure appeared to have distinct differences.

• Journal of the Korea Institute of Building Construction
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• v.18 no.2
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• pp.141-149
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• 2018

In this study, compacting, passing performance, segregation resistance and rheological properties were tested to improve the stability of fresh concrete in the production and construction of self-compacting concrete (SCC) using hollow glass powder(GB). As a result, T50 reaching time was shortened up to amount of GB $2.0kg/m^3$. The compacting according to the amount of GB was improved by ball bearing effect of GB. However, T50 reaching time was slightly increased at $4.0kg/m^3$. In the case of passing performance, the result showed that plain was Class 1, GB $0.5{\sim}2.0kg/m^3$ was Class 0, GB $4.0kg/m^3$ was Class 1. Therefore, the passing performance was improved with 'No blocking' up to amount of GB $2.0kg/m^3$. Passing performance Block step (PJ) number by J-ring method was also best at GB $1.0kg/m^3$. In the case of segregation resistance according to the amount of GB, dynamic segregation resistance was increased compared to plain regardless of the amount of GB. And static segregation resistance showed 2.5% of segregation rate at GB $1.0kg/m^3$. Therefore, it was greatly improved compared to plain (12.5%). In the case of rheology property according to the amount of GB, plastic consistency by increasing of GB content didn't show big difference. However, yield stress by increasing of GB content was decreased with GB $1.0kg/m^3$. In conclusion, GB $1.0kg/m^3$ was effective for improvement of compacting, passing performance and yield stress. Also, it will be useful for stability of SCC by improving segregation.

• Korean Journal of Environmental Biology
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• v.35 no.2
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• pp.105-115
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• 2017

The present study is to understand the Bongseonsa stream in the National Arboretum fish fauna variation through comparison with historical data and to evaluate the stream health situated. We performed investigations over three times from April to September 2015. In the survey, 2,960 individuals which belonging to 22 species, 8 families were collected. Dominant species by number was Zacco platypus and subdominant species was Zacco koreanus. Seven Korean endemic species (Squalidus gracilis majimae, Microphysogobio yaluensis, Zacco koreanus, Koreocobitis rotundicausata, etc) were observed and showed a ratio of 36.4%. The community analysis revealed that the structure of fish community in the study sampling sites was instability in having dominance 0.79 (${\pm}0.15$), diverse 1.21 (${\pm}0.60$), evenness 0.58 (${\pm}0.15$) and species richness 1.49 (${\pm}0.83$). The values in the Qualitative Habitat Evaluation Index (QHEI) was averagely 122.9 (${\pm}44.8$) in the Bongseonsa stream and this was showed to have favorable habitat surroundings. As a result of tolerance guild analysis, the total number of sensitive species and intermediate species were higher than tolerant species. Analysis was divided into A and B two groups of fiducial 12.25% in Cluster analysis degree of similarity between study sampling sites. Fish Assessment Index (FAI) was rated A and B grade in Bongseonsa stream that stream health showed favorable. However Wangsuk stream as a urban stream rated C grade and analysed the lowest grade in the whole study sampling sites. There was high correlation beteween FAI and various indexes, dominance, diverse, evenness and sensitive species and intermediate species.

• Korean Journal of Environment and Ecology
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• v.19 no.3
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• pp.287-298
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• 2005

This study was carried out to offer the raw data on conservation of land and natural environment by constructing groups of indicators to objectively and rationally assess the sustainable natural ecosystem and present the direction for establishing and planning the environmental policy. There were selected that four assessment items were biotic, abiotic, qualitative, and functional factor. And there were extracted fifty-six indicators including density, total nitrogen, hemeroby degree, and goods production. As assessment items and indicators were over 0.6, the design of questionnaire showed no great problem. In the results of correlation analysis of assessment indicators, sociality and dominance was highly correlative in biotic factor, soil property and aspect in abiotic factor, naturalized and urbanized index in qualitative factor, and protection of landslide and soil erosion were too correlative. In the results of deciding the dimension by multidimensional scaling, as stress values were from 0.042 to 0.133, index of fit over 0.9, there no statistical problems. In case of X axis, biotic factor was structure, viewpoint in abiotic factor, composition in qualitative factor, and object in functional factor, and Y axis was shaped Into form, range, structure, and activity.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.51-62
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• 2007

Recently, the pavement distresses in the bridge deck have seriously affected the durability of bridge deck and driver's safety. The existing asphalt materials have the limitations in reducing the pavement distresses of brides deck. To protect the bridge deck and withstand the high deflection, it is necessary to develop the asphalt materials with good fatigue resistance for bridge deck pavement. The asphalt binder combined with SBS and two other admixtures has been developed for improving the resistance to fatigue cracking, productivity, and workability for bridge deck pavement. Based on the various binder test results, the developed binder is found to be PG 70-34 indicating very higher resistance against fatigue cracking. Fatigue testing, wheel tracking testing, and moisture susceptibility testing have been conducted to evaluate the performance of asphalt mixtures developed in this study. Laboratory test results show that the developed asphalt material has three times higher fatigue lives than the typical modified asphalt mixture. Full scale accelerated testing was also performed on the typical asphalt mixture and newly developed asphalt mixture to evaluate the full scale performance of asphalt mixtures. Test results indicate that the length of cracking on the new materials is only 38% of the typical material at the 250,000 load repetitions.