• Korean Membrane Journal
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• 제1권1호
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• pp.100-105
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• 1999

A novel system to thicken the concentrated colloidal solution from membrane water treat-ment processes was developed. A hollow-fiber microfilter(hydrophilic polyethylene nominal pore size 0.1 ${\mu}$m total surface area 0.42 m2) was installed in an acrylic housing that has an aeration port 5 cm below the membrane and a clarifier in the bottom. The concentrate was uniformly supplied from the top of the housing. Bacuum filtration caused downward flow of concentrate and as a result thickening interface. The addition of poly-aluminum chloride (PAC) resulted in rapid increase of trans-membrane pressure (TMP) and in no improvement of the filtered water turbidity and thickening process. Two types of con-centrate and concentrate turbidity had little effect on the increase of TMP and concentrate thickening. It was observed that for the same height of membrane housing membrane surface area to housing volume (A/V) ratio had significant effect on the increase of TMP. When the housing volume was increased ten times the increasing rate of TMP was three times faster as compared to the original housing. A hydraulic model successfully simulated the formation and sedimentation of thickening interface.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1996년도 추계 학술발표회
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• pp.53-58
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• 1996

The Chitin Thiocarbonate-Fe(II)-H2O2 redox initiator system was investigated for the graft copolymerization of acrylonitrile(AN) and acrylic acid(AA) monomers onto chitin powder. The reactions with vinyl monomers onto chitin were carried out under various the graft copolymerization conditions to elucidate the polymerization behavior in terms of graft yield. Reactions of chitin-acrylonitrile graft copolymer with hydroxyl amine hydrochloride and those with sodium hydroxide were conducted in order to obtain chitin-(amidoxime-co-acrylonitrile) and chitin-(acrylate-co-acrylamide) graft copolymers, respectively. The reaction efficiency was observed to depend on the alkali concentration, time, temperature, and the reactant concentrations. The prepared chitin derivatives were evaluated to find potential applications for use in wastewater treatments for adsorption and desorption of heavy metal ions as well as acidic and basic dyes.

• 한국의류학회지
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• 제34권10호
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• pp.1611-1620
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• 2010

This research compares the difference of each preference segments' subjective hands and sensibilities in order to analyze the correlations among preference, subjective hands, and sensibilities. Preference segments were classified into wool, acrylic, and long stitch length-preferred clusters in previous research. To evaluate the subjective hands and sensibilities of knit fabrics, the 20's and 30's women rated twelve knit fabrics by touching, using a questionnaire with a seven-point semantic differential scale. These twelve knit fabrics were differentiated by controlling the mixture ratio and stitch length using a computer-controlled automatic flat knit machine. The difference of each preference segments' subjective hands and sensibilities was determined using the conjoint analysis. The clusters perceived the subjective hands and sensibilities differently according to preferred constituent characteristics. There was no correlation between surface unevenness and preference in wool-preferred cluster, while there were negative correlations in other clusters. The acrylic-preferred cluster had a preference in coolness compared to other clusters; in addition, the long stitch-preferred cluster preferred flexibility/bulkiness and extensibility than the others. All clusters preferred modem and natural sensibilities that were caused by different constituent characteristics of knit fabrics.

• 한국염색가공학회지
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• 제18권6호
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• pp.80-87
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• 2006

Nowadays, interests of ultraviolet(UV) protection increased, since the UV dosage on the earth surface has increased over years. Overdose of UV can cause various skin, eye, and even DNA damages. Therefore, it is need to develop a proper mean to protect human skin and eye from UV radiation. In this study, the UV protective effect of green tea extract dyed fabrics with various fiber types were examined. Green tea has an active moiety called 'catechin' having benzene rings in its structure, which would exert a proper UV protective property. Green tea dyed fabrics showed the increase in UV protection, and silk showed the highest increase in UV protection (from 52.2% to 84.5% in UV-A, from 66.1% to 90% in UV-B). The order of UV-A protection increase is silk, wool, nylon and acrylic, PET, and cotton. The order of UV-B protection increase is silk nylon, wool, acrylic, cotton, and PET. In case of silk and nylon, the UV protection property gradually increased as the concentration of green tea extract increased. As a result, it was proven that green tea extract dyeing can improve UV protection property of dyed fabrics in environment-friendly and biocompatible manners.

• Macromolecular Research
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• 제14권5호
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• pp.552-558
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• 2006

Biodegradable nanofibrous poly(L-lactic acid) (PLLA) scaffold was prepared by an electrospinning process for use in tissue regeneration. The nanofiber scaffold was treated with oxygen plasma and then simultaneously in situ grafted with hydrophilic acrylic acid (AA) to obtain PLLA-g-PAA. The fiber diameter, pore size, and porosity of the electrospun nanofibrous PLLA scaffold were estimated as $250\sim750nm,\;\sim30{\mu}m$, and 95%, respectively. The ultimate tensile strength was 1.7 MPa and the percent elongation at break was 120%. Although the physical and mechanical properties of the PLLA-g-PAA scaffold were comparable to those of the PLLA control, a significantly lower contact angle and significantly higher ratio of oxygen to carbon were notable on the PLLA-g-PAA surface. After the fibroblasts were cultured for up to 6 days, cell adhesion and proliferation were much improved on the nanofibrous PLLA-g-PAA scaffold than on either PLLA film or unmodified nanofibrous PLLA scaffold. The present work demonstrated that the applications of plasma treatment and hydrophilic AA grafting were effective to modify the surface of electrospun nanofibrous polymer scaffolds and that the altered surface characteristics significantly improved cell adhesion and proliferation.

• 한국의류학회지
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• 제32권4호
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• pp.651-658
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• 2008

Conjoint analysis estimates how much each of the attributes is valued on the basis of the choices consumers make among product concepts that are varied in systematic ways. The purposes of this research were to evaluate the relative importance of each fabric constituent characteristic for the consumer's utility or preference, to compare with the relative importance between the trained and the untrained panelists, and to identify the combinations of the constituent characteristic of knit fabric which offer consumers greater utility. Conjoint analysis was conducted using data taken from 54 trained and 54 untrained panelists, who rated preference for 12 different knit fabrics. The stitch length had a greater effect on knit fabric preference than the mixture ratio of fiber. There was no difference on effect of knit constituent characteristics for preference between the trained and the untrained panelists. Total, trained and untrained group preferred a knit fabric that had a higher acrylic mixture ratio and a short stitch length.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.25-26
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• 2018

Various concrete material technologies and new materials have been developed in accordance with the advancement of buildings. As part of these new technologies, light transparent concrete, which was invented by Hungarian architect Aron Losonczi and attracted worldwide attention, has a technique of arranging optical fiber inside concrete and transmitting the light from exterior to concrete to show silhouette inside. However, due to many disadvantages, application to the field was limited and commercialization was not easy. In Korea, Light Emotion Friendly Concrete has been developed for commercialization. In order to solve the degradation of construction performance caused by the arrangement of expensive optical fiber, which is pointed out as a disadvantage of translucent concrete, It converts expensive fiber into low cost acrylic rod, easy to arrange, pre-assembled to form and post-cast. Therefore, this study aims to improve the mechanical properties of LEFC and to derive optimal combination.

• 멤브레인
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• 제23권4호
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• pp.312-318
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• 2013

Poly vinylidene fluoride (PVDF) 중공사막을 polyethylenimine (PEI)와 p-xylylene dichloride (XDC)를 이용해 친수화 시킨 후 poly(vinyl alcohol) (PVA)과 가교제인 poly(acrylic acid-co-maleic acid) (PAM) 혼합용액을 코팅하여 막을 제조하였다. 중공사막 표면의 코팅여부는 scanning electron microscope (SEM)을 통해 관찰하였으며, 막의 특성평가를 위해 물/에탄올 혼합액에 대한 투과증발 실험을 수행하였다. 공급액 조성은 90 wt% 에탄올 수용액을 사용하였으며, 가교제 농도, 공급액과 반응온도 변화에 따른 투과도 및 선택도를 측정하였다. 투과도는 반응온도 $100^{\circ}C$, PAM 농도 3 wt%, 공급액온도 $70^{\circ}C$에서 $1,480g/m^2hr$, 그리고 선택도는 반응온도 $100^{\circ}C$, PAM 농도 15 wt%, 공급액온도 $25^{\circ}C$에서 ${\alpha}_{W/E}=82$의 결과를 얻을 수 있었다.

• 한국의류학회지
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• 제32권12호
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• pp.1981-1989
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• 2008

개개인은 다른 이유를 가지고 동일한 또는 유사한 제품들을 구매한다. 추구 효익이란 동일한 속성에 동일한 상대적 중요성의 수준을 가지는 사람들을 군집하여 이러한 차이를 이해하려는 것이다. 본 연구에서는 니트 소재의 구성특성에 대한 추구 효익에 따라 소비자들을 세분화하고, 컨조인트 분석을 이용하여 선호도에 대한 구성특성들의 상대적 중요성을 비교 분석하여 세분화 집단에 따른 선호도에 유의한 차이가 있는지 분석하였다. 효용도에 따라서 양모 섬유를 선호하는 집단, 아크릴 섬유를 선호하는 집단과 긴 편환장을 선호하는 집단, 세개의 군집이 도출되었으며, 이들은 다른 구성특성의 이상적인 니트 소재를 선호하는 것으로 나타났다. 군집들 간에 니트 소재의 혼용률과 편환장에 대한 선호도에 유의한 차이가 있는 것으로 나타났다. 양모 섬유를 선호하는 집단은 양모 혼용률이 크고 짧은 편환장을 선호하였으며, 아크릴 섬유를 선호하는 집단과 긴 편환장을 선호하는 집단은 아크릴 혼용률이 크고 긴 편환장을 선호하였다.

• 멤브레인
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• 제1권1호
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• pp.100-100
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• 1991

A novel system to thicken the concentrated colloidal solution from membrane water treat-ment processes was developed. A hollow-fiber microfilter(hydrophilic polyethylene nominal pore size 0.1 μm total surface area 0.42 m2) was installed in an acrylic housing that has an aeration port 5 cm below the membrane and a clarifier in the bottom. The concentrate was uniformly supplied from the top of the housing. Bacuum filtration caused downward flow of concentrate and as a result thickening interface. The addition of poly-aluminum chloride (PAC) resulted in rapid increase of trans-membrane pressure (TMP) and in no improvement of the filtered water turbidity and thickening process. Two types of con-centrate and concentrate turbidity had little effect on the increase of TMP and concentrate thickening. It was observed that for the same height of membrane housing membrane surface area to housing volume (A/V) ratio had significant effect on the increase of TMP. When the housing volume was increased ten times the increasing rate of TMP was three times faster as compared to the original housing. A hydraulic model successfully simulated the formation and sedimentation of thickening interface.