• 한국생활과학회지
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• 제21권4호
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• pp.781-790
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• 2012

In midst of growing interest and awareness towards sustainability and being "green", there has been increased demand for sustainable clothing. In the purpose of boosting eco-friendly textiles industry, this research was conducted by investigating environmentally-conscious clothing behavior of university students and assessing their views on eco-friendliness of fibers. Thus, their awareness on recycled polyester fiber was evaluated. The research was conducted by surveying 257 university students residing in Daejeon. The data were analyzed with descriptive statistics, factor analysis, and reliability analysis, using SPSS 19.0. The results were as follows. 1) The majority of the subjects answered "Disposing clothing in the clothing recycling container" to reduce environmental impact. 2) Six factors of eco-friendliness of fiber were extracted as reutilization, unfinishedness, economics, environment preservation, natural materials, and slow fashion by using factor analysis. 3) Subjects scored organic cotton as most eco-friendly among various fibers. Recycled polyester fiber was graded less sustainable than natural fiber, but more eco-friendly than artificial one. 4) In assessment of subject's awareness of recycled polyester fiber, they highly valued on resource-reutilization and economics, but less valued on its hygiene, thermal insulation and health-functionality.

• Computers and Concrete
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• 제30권6호
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• pp.421-432
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• 2022

Recently, the interminable ozone depletion and the global warming concerns has led to construction industries to seek for construction materials which are eco-friendly. Regarding this, Geopolymer Concrete (GPC) is getting great interest from researchers and scientists, since it can operate by-product waste to replace cement which can lead to the reduction of greenhouse gas emission through its production. Also, compared to ordinary concrete, geopolymer concrete belongs improved mechanical and durability properties. In spite of its positive properties, the practical use of geopolymer concrete is currently limited. This is primarily owing to the scarce structural, design and application knowledge. This study investigates the Mechanical and Durability of Geopolymer Concrete Containing Fibers and Recycled Aggregate. Mixtures of elastoplastic fiber reinforced geopolymer concrete with partial replacement of recycled coarse aggregate in different proportions of 10, 20, 30, and 40% with natural aggregate were fabricated. On the other hand, geopolymer concrete of 100% natural aggregate was prepared as a control specimen. To consider both strength and durability properties and to evaluate the combined effect of recycled coarse aggregate and elastoplastic fiber, an elastoplastic fiber with the ratio of 0.4% and 0.8% were incorporated. The highest compressive strength achieved was 35 MPa when the incorporation of recycled aggregates was 10% with the inclusion of 0.4% elastoplastic fiber. From the result, it was noticed that incorporation of 10% recycled aggregate with 0.8% of the elastoplastic fiber is the perfect combination that can give a GPC having enhanced tensile strength. When specimens exposed to freezing-thawing condition, the physical appearance, compressive strength, weight loss, and ultrasonic pulse velocity of the samples was investigated. In general, all specimens tested performed resistance to freezing thawing. the obtained results indicated that combination of recycled aggregate and elastoplastic fiber up to some extent could be achieved a geopolymer concrete that can replace conventional concrete.

• 한국건축시공학회지
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• 제16권3호
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• pp.201-209
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• 2016

본 연구에서는 천연섬유인 KN섬유를 섬유보강 콘크리트에 사용하기 위한 방안으로, KN섬유의 혼입량 및 유기질 섬유보강재 종류에 따른 콘크리트의 공학적 특성을 실험적으로 확인하였다. 이러한 연구를 위하여 KN섬유의 혼입량 4종류(0, 0.3, 0.6 및 $0.9kg/m^3$) 및 비교용 섬유보강재(JT, CEL, PP 및 NY섬유) 4종류를 대상으로 슬럼프, 공기량, 소성수축 시험 및 압축강도, 인장강도, 휨강도, 그리고 건조 수축량, 탄산화 깊이 등을 실험하였다. 실험결과, KN섬유의 혼입량 $0.6kg/m^3$일 때, 인장강도 및 휨강도 증진에 매우 효과적이며, 소성수축 균열 및 건조수축량 저감, 탄산화 깊이에도 큰 효과가 있는 것으로 나타났다. 또한, 동일한 혼입량($0.6kg/m^3$)을 사용한 유기질 섬유보강재와의 비교실험에서 탄산화 깊이를 제외한 인장강도 및 휨강도, 소성수축 균열 및 건조수축량 저감 등에 KN섬유가 우수한 것으로 나타났다. 따라서, KN섬유의 혼입량 $0.6kg/m^3$를 사용하여 섬유보강 콘크리트에 적용하는 것이 콘크리트의 성능 및 환경성, 경제성 측면에서 가장 적합한 것으로 나타났으며, 향후 현장적용성에 대한 지속적인 연구가 요구된다.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2012년도 제46차 학술발표회
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• pp.42-42
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• 2012

팥에 함유되어있는 색소와 관련된 연구 중에서는, 검정팥의 색소성분을 분리하여 delphinidin-3-glucoside(D-3-G)로 보고한 Sasanuma의 연구와 검정팥 껍질속에 포함된 안토시아닌의 함량을 평가한 Yoshida의 연구 결과 등이 있다. 본 연구에서는 검정팥 종피에서 색소를 추출하여, 적정 염색조건을 설정하였으며, 매염제별 색상변화 및 견뢰도를 측정하는 과정을 통해 염색 특성을 파악하여 새로운 천연염재로서의 활용 가능성을 진단하였을 뿐만 아니라 응용 연구를 위한 기초자료의 확보에 주안점을 두었다. pH에 따른 염색성에서는 견직물의 경우 pH 4에서 가장 염착량이 많았고, 면직물의 경우에는 주어진 범위내에서는 pH가 높을수록 염착량이 많았다. 염색온도와 시간에 따른 염색성은, 견직물의 경우, 염색온도 $80^{\circ}C$에서는 시간이 경과할수록 K/S 값이 크게 나타났으며, 면직물의 경우도 견직물과 비슷한 결과로 온도가 높아질수록 염색시간이 경과될수록 K/S 값이 크게 나타났다. 견직물에 대한 매염제 종류별 표면색의 변화에서는 Fe 매염포만 $YR{\rightarrow}Y$ 로 변화되었을 뿐 다른 매염제에서는 매염 후에도 색상 변화는 크지 않았다. 매염처리 전 견직물의 일광 견뢰도는 무매염이 4~6등급, Al 처리포는 4~5등급, Cu와 Sn은 3~4등급으로 나타났고 Fe는 2~3등급으로 가장 낮게 나타났으며, 세탁견뢰도에서는 무매염 2등급, 매염제 처리의 경우 2~3등급으로 나타났다. 무매염 면직물의 일광견뢰도는 1~2 등급, Fe 매염은 2~3등급, Cu 2등급 Al과 Sn은 1~2등급으로 매염처리에 의해 전혀 개선되지 않았으며, 세탁견뢰도의 경우 Cu매염이 4등급으로 양호하게 나타났으며 무매염, Al, Sn과 Fe는 3등급으로 나타났다.

• Steel and Composite Structures
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• 제44권5호
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• pp.707-720
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• 2022

In the present work, bending and free vibration analyses of multilayered functionally graded (FG) graphene platelet (GPL) and fiber-reinforced hybrid composite beams are carried out using the parabolic function based shear deformation theory. Parabolic variation of transverse shear stress across the thickness of beam and transverse shear stress-free conditions at top and bottom surfaces of the beam are considered, and the proposed formulation incorporates a transverse displacement field. The present theory works only with four unknowns and is computationally efficient. Hamilton's principle has been employed for deriving the governing equations. Analytical solutions are obtained for both the bending and free vibration problems in the present work considering different variations of GPLs and fibers distribution, namely, FG-X, FG-U, FG-Λ, and FG-O for beams having simply-supported boundary condition. First, the matrix is assumed to be strengthened using GPLs, and then the fibers are embedded. Multiscale modeling for material properties of functionally graded graphene platelet/fiber hybrid composites (FG-GPL/FHRC) is performed using Halpin-Tsai micromechanical model. The study reveals that the distributions of GPLs and fibers have significant impacts on the stresses, deflections, and natural frequencies of the beam. The number of layers and shape factors widely affect the behavior of FG-GPL-FHRC beams. The multilayered FG-GPL-FHRC beams turn out to be a good approximation to the FG beams without exhibiting the stress-channeling effects.

• Animal cells and systems
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• 제7권4호
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• pp.331-335
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• 2003

Vertebrates with different habitats have different proportions of visual cells, with the rod cells responding to scotopic vision and the cone cells responding to photopic and color vision in their retinas. The present work studied whether the kinds and arrangement patterns of the cone cells and interlocking morphology of the lens were related to the kind of preys and habitats in the genus Zacco. The retinas were observed by a light microscopy using H-E staining method and the interlocking formula of the lens fibers were investigated by a scanning electron microscopy. The interlocking formula of the lens fibers of Z. temmincki is an ' anchor and socket ' connection, and that of Z. platypus is a ' ball and socket ' connection. The cone cells of Z. platypus and Z. temmincki constituted compacted mosaic patterns of row type. Away from the center, the double and single cone cells gradually increased in diameter. Zacco temmincki had identical double cone cells and Z. platypus had non-identical double and single cone cells. The eyes of Z. temminckifeeding on a moving aquatic insects in relative limpid water and swift current of mid and upper stream have better resolution than that of Z. platypus feeding on mainly adhesive algae and some aquatic insects in slightly turbid water of mid stream.

• Applied Microscopy
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• 제26권2호
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• pp.221-233
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• 1996

In order to study process of spermiogenesis of the Korean manchurian field mouse, Apodemus spesiosus peninsulae, the testis obtained from sexually matured male reproductive organs, were examined with electron microscopy, and the following results were obtained based on the characters of cell differentiation. 1. According to the features of cell structure, spermiogenesis of the Apodemus spesiosus peninsulae was five phases: Golgi, cap, acrosome, maturation and spermiation phase. They were further subdivided into two steps of early and late phases respectively. Hence, the spermiogenesis consists of ten steps. 2. In the changes of the chromatin, the chromatin granules began to be condenced in the cap phase and regularizated at maturation phases, and a perfect nucleus of sperm was formed at the spermiation phases. 3. The formative period of sperm tail began to be develop in the early Golgi phase and completed at the spermiation phases 4. The outer dence fibers of middle piece were arranged in a horseshoe fashion. Nos. 1, 5, 6 and 9 of the outer dense fibers were larger than the others. The structure of axoneme in the middle piece was 9+2, and the axonemal complex consists of A and B microtubules, dynein arms and radial links.

• Advanced Composite Materials
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• 제16권4호
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• pp.335-347
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• 2007

Green composites composed of long maize fibers and poly $\varepsilon$-caprolactone (PCL) biodegradable polyester matrix were manufactured by the thermo-mechanical processing termed as 'Sequential Molding and Forming Process' that was developed previously by the authors' research group. A variety of processing parameters such as fiber area fraction, molding temperature and forming pressure were systematically controlled and their influence on the tensile properties was investigated. It was revealed that both tensile strength and elastic modulus of the composites increase steadily depending on the increase in fiber area fraction, suggesting a general conformity to the rule of mixtures (ROM), particularly up to 55% fiber area fraction. The improvement in tensile properties was found to be closely related to the good interfacial adhesion between the fiber and polymer matrix, and was observed to be more pronounced under the optimum processing condition of $130^{\circ}C$ molding temperature and 10 MPa forming pressure. However, processing out of the optimum condition results in a deterioration in properties, mostly fiber and/or matrix degradation together with their interfacial defect as a consequence of the thermal or mechanical damages. On the basis of microstructural observation, the cause of strength degradation and its countermeasure to provide a feasible composite design are discussed in relation to the optimized process conditions.

• 한국의류학회지
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• 제23권1호
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• pp.140-146
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• 1999

Colorants in green tea were extracted freeze-dried and analyzed to investigate the possibility of using as a natural dye. Fractionation of the colorants was carried out by column chromatograpy. Colorants in green tea were eluted into five fractions. All the fractions except fraction F2 showed absorption peakat 280nm. Fraction f2 showed absorption peak at 270nm and broad peak at 350nm, From the IR analysis it is speculated that fractions F2-F5 having similar stucture but different molecular weight are catechis. Silk fabrics dyes with fractions F1-F4 showed yellowish red color while sample dyed with fraction F5 showed red color. The colorants from green tea infusion was applied to silk wool nylon cotton and rayon fabrices. It showed relatively good affinity to protein and polyamide fibers bur low affinity to cellulose and regenerated cellulose fibers.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2007년도 추계학술발표논문집
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• pp.93-102
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• 2007

Biocomposite was organized with biodegradable polymer and natural fiber that has potential to be used as replacement for glass fiber reinforced polymer composite with the benefits of low cost, low density, acceptable specific strength, biodegradability, etc. Until now, non-wood fibers have been used as reinforcements of biocomposite which are all plant-based fibers. The present study focused on investigating the fabrication and characterization of biocomposite reinforced with red algae fiber. The bleached red algae fiber(BRAF) showed very similar crystallinity to the cellulose. It has high stability against thermal degradation (maximum thermal decomposition temperature of 359.3$^{\circ}C$) and thermal expansion. Biocomposites reinforced with BRAF have been fabricated by a compression molding method and their mechanical and thermal properties have been studied. The storage modulus and the thermomechanical stability of PBS matrix are markedly improved with reinforcing the BRAF. These results support that the red algae fiber can be used as an excellent reinforcement of biocomposites as "green-composite" or "eco-composite".