• KSBB Journal
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• v.24 no.4
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• pp.361-366
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• 2009

Response surface methodology (RSM) was used for optimization the fraction conditions of xylose from pepper stem with dilute sulfuric acid. The independent variables were acid concentration in the range of 1.134 to 2.866%, reaction temperatures in the range of 142.68 to $177.32^{\circ}C$, and hydrolysis time in the range of 6.34 to 23.66 min. were studied. The dependent variables were xylose yield from pepper stem, and the production of by-products, for example, furfural, acetic aicd, HMF etc. Experimental results had a good match with statistical result. The maximum xylose yield obtained in this experiment was 71% concentration.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.5
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• pp.753-758
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• 2013

The physicochemical, sensory, and functional properties of Codonopsis (C.) lanceolata tea with different amounts of sugar (25%, 50%, 75%, and 100%) were investigated. There were no significant changes in crude protein, crude fat, and ash contents of C. lanceolata tea with different amounts of sugar. In contrast, carbohydrates decreased and moisture content increased in C. lanceolata tea with different amounts of sugar. The natural presumption is that carbohydrates increase with increasing amounts of sugar. In terms of color, the L-value decreased and the b-value increased with increasing amounts of sugar. Although there were no significant changes in total dietary fiber, soluble dietary fiber increased and insoluble dietary fiber decreased with increasing amounts of sugar. The total phenolic and flavonoid content increased, while saponin content remained constant with increasing amounts of sugar. The highest overall acceptability values in the sensory test for color, flavor, taste, and overall preference were 5.77, 5.82, 5.72, and 5.95, respectively, with the addition of 75% sugar.

• KSBB Journal
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• v.21 no.6 s.101
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• pp.410-413
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• 2006

The composition of two Bokbunja (Rubus coreanus Miquel) wines (one without mushroom extracts (wine A) and the other is with the extracts (wine B)) has been investigated to improve the quality of Bokbunja wine. The content of solid particle, acidity, crude ash, crude protein of the wine A were 10.5%, 1.36%, 0.45% and 0.05% and those of wine B were 7.4%, 0.54%, 0.31%, and 0.22%, respectively. Crude fat and crude fiber were not detected in both samples. To verify the flavor quality of Bokbunja wine, the volatile components from ethylether extracts of two wines were analyzed using GC/FID and GC/MS. A total number of 12 volatile flavor compounds (6 alcohols, 3 ketones, 1 acid, 1 ester and 1 anhydride) were identified in the two Rubus wines. The major volatile compounds of the wines were 2,3-butanediol, 2,5-furanedione, phenylethyl alcohol, and butanedioic acid and they might affect the major role in the unique flavor of Bokbunja wines.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2000.12a
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• pp.53-53
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• 2000

최근 복분자(산딸기)의 효능을 이용한 일반식품 및 기능성 식품 등의 제품 개발이 활발히 추진되고 있다. 따라서 본 연구에서는 식품차원의 연구분야 일환으로서 먼저 복분자의 일반성분, 유리당, 유리아미노산, 무기성분 및 향기성분 등을 보고한 후 앞으로 생리 활성 연구 분야에 초점을 두고 연구를 진행할 하여 학문적 자료 및 산업에 응용할시 기초자료로 활용하고자 한다. 복분자의 수분은 5.39%, 총당은 17.3%, 환원당은 8.6%, 조단백질 10.6%, 조회분은 4.5%, 조지방은1.7%, 조섬유는 3.9%이고, 유리당 함량은 sucrose 1.52%, fructose 3.98%, glucose 1.24%이고, 유기산 함량은 citric acid 10.2%, oxalic acid 6.29%로 가장 많이 함유하고 있었고, 그 다음은 malic acid 1.94%였다. 총 아미노산은 7914.1mg%이고, 필수아미노산 함량은 2622.5mg%로 나타났다. 복분자에 가장 많이 함유되어 있는 아미노산은 aspartic acid 1260.3%, 그 다음은 glutamic acid 1054.3% 순으로 함유하고 있었다. 무기성분 K가 387mg으로 가장 많이 함유되어 있었고, 복분자에서 총 52종의 성분이 화인되었는데 확인된 성분들은 관능기별로 분류하면 amylalcohol를 포함한 alcohol류 11종, valeric acid를 포함한 acid류 13종, hexanal를 포함한 carbonyl류 20종, 2-heptanone를 포함한 hydrocabon류 5종 그리고 methyl palmitate를 포함한 ester류가 3종 이었다. 관능기별로 확인된 성분들의 총 peak area%를 살펴보면 alcohol류 11.56%, acid류 38.87%, hydrocarbon류 2.89%, ester류 0.80%, 총 70.32%가 확인되었다. Alcohol류에서 linalool가 3.78%, acid류에서는 caproic acid류가 14.40%, carbonyl류에서 2-hydroxy-4-methoxyacetophenone이 2.99%, hydrocabon류에서는 aromadendrene가1.59% 그리고 ester류에서는 methyl palmitate가 0.43%으로 가장 많이 함유하고 있었다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.1
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• pp.8-15
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• 2021

TiO2 has been used in various fields such as solar cells, dental implants, and photocatalysis, because it has high physical and chemical stability and is harmless to the body. TiO2 nanofibers which have a large specific surface area also show a good reactivity in bio-friendly products and excellent photocatalysis in air and water purification. To fabricate TiO2 nanofibers, an electrospinning method was used. To observe the diameter of TiO2 nanofibers with fabrication variables, the fabrication variables was divided into precursor composition variables and process variables and microstructure was analyzed. The concentrations of PVP (Polyvinylpyrrolidone) and TTIP (Titanium(IV) isopropoxide) were selected as precursor composition variables, and inflow velocity and voltage were also selected as process variables. Microstructure and crystal structure of TiO2 nanofibers were analyzed using FE-SEM (Field emission scanning electron microscope) and XRD (X-ray diffraction), respectively. As-spun TiO2 nanofibers with an average diameter of about 0.27 ㎛ to 1.31 ㎛ were transformed to anatase TiO2 nanofibers with an average diameter of about 0.22 ㎛ to 0.78 ㎛ after heat treatment of 3 hours at 450℃. Anatase TiO2 nanofibers with an average diameter of 0.22 ㎛ can be expected to improve the photocatalytic properties by increasing the specific surface area. To change the average diameter of TiO2 nanofibers, the control of precursor composition variables such as concentrations of PVP and TTIP is more efficient than the control of electrospinning process variables such as inflow velocity and voltage.

• Science of Emotion and Sensibility
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• v.19 no.3
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• pp.43-50
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• 2016

The uniform nanofibers of polyurethane with different contents of Juniperus Chinensis extracts were successfully prepared by electrospinning method. Polyurethane is widely used as functional polymers in the industrials, medical field as their properties can be tailor-made by adjusting their compositions. Juniperus Chinensis has been reported for anti-tumor, anti-bacterial, anti-fungal, and anti-viral activities. PU/Juniperus Chinensis extracts composite nanofibers were produced at different Juniperus Chinensis extracts concentrations (0.25, 0.5, 1, 1.5wt.%). The effects of the major parameters in electrospinning process such as tip to collector distance (TCD), voltage, polymer concentration on the average diameter of electrospun nanoweb were investigated. As results, 12wt% PU solution concentration, 8kV applied voltage and 15cm tip to collector distance were identified as optimum conditions for electrospinning the composite nanofibers. The diameter and morphology of the nanocomposite nanofibers were confirmed by a scanning electron microscopy (SEM). The resulting fibers exhibited a uniform diameter ranging from 435nm~547nm. It has been found that the average diameters of fibers decreased by the adding of Juniperus Chinensis extracts. These nanowebs can be used for medical materials, protective clothing, and antimicrobial filters.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.12
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• pp.1345-1350
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• 2014

This paper presented analysis methods for adapting E-glass fiber/epoxy composite (GFRP) materials to an automotive leaf spring. It focused on the static behaviors of the leaf spring due to the material composition and its fiber orientation. The material properties of the GFRP composite were directly measured based on the ASTM standard test. A reverse implementation was performed to obtain the complete set of in-situ fiber and matrix properties from the ply test results. Next, the spring rates of the composite leaf spring were examined according to the variation of material parameters such as the fiber angles and resin contents of the composite material. Finally, progressive failure analysis was conducted to identify the initial failure load by means of an elastic stress analysis and specific damage criteria. As a result, it was found that damage first occurred along the edge of the leaf spring owing to the shear stresses.

• Journal of the Korean Wood Science and Technology
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• v.42 no.6
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• pp.700-707
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• 2014

The effect of steam and ozone pretreatments on fibrillation efficiency by wet disk-milling was investigated. Hemicellulose (40%) and lignin (42%) of Korean white pine were partially removed by steam and ozone pretreatments, respectively. With increasing wet disk-milling time, the diameter of fibers was significantly decreased and its size distribution became narrow. Especially, the average diameters of lignocellulose nanofibers after steam and ozone pretreatments were 19 nm and 12 nm, respectively. Thus-obtained lignocellulose nanofibers-reinforced polyurethane composite was prepared. Tensile strength and elastic modulus were drastically improved with increasing wet disk-milling time and lignocellulose nanofiber content. Nanocomposite reinforced by lignocellulose nanofibers after two pretreatments showed higher tensile properties, compared to that reinforced by lignocellulose nanofiber without pretreatment, at the similar wet disk-milling time.

• Journal of the Korean Geotechnical Society
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• v.31 no.4
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• pp.5-12
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• 2015

The construction of waste landfill sites has been increased due to recent expansion of various waste. Geotextiles are widely used for the purpose of reinforcement and protection of waste inside the landfill. Geotextile affects the shear behavior of waste landfill which forms the contact surface with soil. In this study, the effect of acidic and alkaline components in leachate has been analyzed through the laboratory experiment on the shear stress reduction of the contact surface of ground-geotextile under the cyclic load. For this purpose, a dynamic contact surface shear tester has been manufactured, and cyclic simple shear tests have been performed using geotextile and soil specimen which were immersed in chemical solutions for 60 and 840 days, respectively. Based on the Disturbed State Concept, the characteristics of shear stress on the contact surface of ground-geotextile due to chemical factors have been identified by the disturbance function.

• Journal of the Korea Convergence Society
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• v.11 no.5
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• pp.35-41
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• 2020

This study was conducted to develop the efficient system for starch hydrolysis suppression using rutin, quercetin and dietary fiber through the statistical mixture design. The three components were replaced with wheat flour at the level of 10% and the mixed gel with three components was characterized by in vitro starch digestion. The mixture design was applied by simplex-centroid experimental model. The quadratic model (R²=0.86) was well fitted and the obtained regression equation indicated that the significant positive effects was observed in the quercetin and fiber mixture. Based on the statistical results, the best mixing ratio of quercetin and fiber was 72: 28 that led to the lowest predicted glycemic index (pGI). Their interactions on the pGI of starch digestibility were clearly visualized in the 3D surface plot. These results suggested that the mixture of quercetin and fiber interact strongly with wheat flour, consequently retarding starch hydrolysis by 15%.