• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.7 s.250
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• pp.779-786
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• 2006

Woven sisal textile reinforced composites were manufactured to evaluate fracture toughness, and tensile test. All specimens were immersed in water five times. All specimens are immersed in pure water during 9 days at room temperature, and dried in 1 day at $50^{\circ}C$. Two kinds of polymer matrices such as epoxy and vinyl-ester were used. Fractured surface were investigated to study the failure mechanism and fiber/matrix interfacial adhesion. It is shows that it can be enhanced to improve their mechanical performance to reveal the relationship between fracture toughness and water absorption fatigue according to different polymer matrices. Water uptake of the epoxy composites was found to increase with cycle times. Mechanical properties are dramatically affected by the water absorption cycles. Water-absorbed samples observed poor mechanical properties such as lower values of maximum strength and extreme elongation. The $K_{IC}$ values demonstrate a decrease in inclination with increasing cyclic times of wetting and drying fur the epoxy and vinyl-ester.

• Membrane Journal
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• v.1 no.1
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.11
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• pp.2040-2050
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• 2007

In this study, we present a novel method for estimating the information of MU(motor unit) which is the basic element of human muscle by using surface EMG. Some of the method developed in this field could only estimate the numbers of MU that is activated. However, in our study the MU-simulator based on the line source model was designed to estimate the MU information including the numbers of MU and muscle fiber, conduction velocity, MU diameter, fiber diameter, and end plate position. The SMUAP(single motor unit action potential) detector was designed and CMAP(compound muscle action potential) by electrical stimulus was recorded. With these data, the MU-simulator can estimate the MU information by varying muscle paramater settings through MSE(mean square error) method. Our results shows that the proposed method can be comparable with the method of anatomical studies. Moreover, our system can be utilized to build a tool for diagnosis and treatment assessment of neuromuscular patients.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.85-86
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• 2003

Shrink-proofing processing of wool fabrics is practically carried out by means of oxidation of wool with choline and/or covering of wool surface with resins. But, these are not necessarily environmentally friendly process causing a waste fluid containing organic chlorine compounds. Development of alternative method using more environmentally friendly process is desired. In this study, utilization of titanium oxide, TiO$_2$, photocatalytic reaction for the shrink-proofing of wool has been examined. It was found that the treatment of wool by TiO$_2$ photocatalytic reaction gave good shrink-proofing characteristics to wool fabrics.

• Textile Coloration and Finishing
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• v.29 no.4
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• pp.181-194
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• 2017

The biodegradability of polylactic acid(PLA) fabrics was evaluated by two methods: enzyme and soil degradation. Three different enzymes were selected to evaluate. Degradation times were measured at optimal enzyme treatment conditions. Biodegradation by enzymatic hydrolysis was compared with soil degradation. As a result, biodegradation created cracks on the fiber surface, which led to fiber thickening and shortening. In addition, new peak was observed at $18.5^{\circ}$ by degradation. Moreover, cracks indicating biofragmentation were confirmed by enzyme and soil degradation. By enzyme and soil degradation, the weight loss of PLA fabrics was occurred, there through, the tensile strength decreased about 25% by enzyme hydrolysis when 21 days after, and 21.67% by soil degradation when 60 days after. Furthermore, the biodegradability of PLA fabrics by enzymatic and soil degradation was investigated and enzymatic degradation was found to be superior to soil degradation of PLA fabrics. Among the three enzymes evaluated for enzymatic degradation, alcalase was the most efficient enzymes. This study established the mechanism of biodegradation of PLA nonwovens, which might prove useful in the textile industry.

• Journal of the Korean Society of Safety
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• v.14 no.3
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• pp.127-133
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• 1999

One of the major malodorous gas at the working place is hydrogen sulfide and impregnated activated carbon fiber(ACF) was used as a adsorbent to remove this gas. ACF is treated and impregnated with chemicals to increase the adsorption capacity. The experiments showed that the adsorption efficiency for hydrogen sulfide was increased in case of impregnation with $Na_2CO_3$ or KI. Also, by the surface treatment with NaOH, the adsorption efficiency was increased however not so much as impregnation. KI was the best impregnant for this purpose and the optimum concentration was 9wt%. The adsorption capacity of hydrogen sulfide was more than 500mg/g ACF.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.173-174
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• 2003

Activated carbons (ACs) are widely used in adsorption for the removal of gaseous and aqueous pollutants[1,2]. The microbicidal property of ACs is also very important, in order to decrease the risk of water and air contamination with microorganisms. For this purpose, ACs have impregnated with silver or with metallic oxides[2]. However, in the case of Ag supported ACs prepared by impregnation, there are some problem, such as, heat-treatment, highly decrease in specific surface area and pore volume by deposited Ag, and rapidly elution of Ag at the initial stage of usage[3]. (omitted)

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.189-190
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• 2003

섬유강화 복합재료의 사용이 점점 증가함에 따라 구조용 및 내장재 등으로 사용된 수명이 다한 섬유강화 복합재료의 사용후 폐기가 문제가 되고 있다. 특히, 자동차 부품, 건축자재 및 전기절연재 등으로 가장 많이 사용되는 유리섬유 복합재료의 폐기물이 급격히 증가하여 환경 오염문제가 심각해지고 있어서, 환경 친화적인 새로운 복합재료에 대한 필요성이 제기되어 왔다. 따라서 본 연구에서는 천연섬유를 이용한 천연섬유/생분해성 수지계 복합소재를 대상으로 환경적합성이 우수하고 자연환경에서 완전한 생분해성을 가지며, 유리 섬유복합재료를 대체할 물성이 우수한 새로운 Biocomposite를 개발하고자 하였다. (중략)

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2010.03a
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• pp.29-30
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• 2010

Cotton fabric is usually dyed with anionic dyes such as direct and reactive dyes. Naturally, there is no affinity for basic dyes to cotton fiber. In this study, to improve the dyeability of cotton fiber with cationic dyes, the fabric was pretreated with air plasma and grafted with acrylic acid to create acidic groups on the surface of cotton fibers. The grafted samples were dyed with natural cationic dye extracted from roots of berberis vulgaris. The effect of plasma treatment and grafting of acrylic acid on the color strength of cotton fabric was studied.

• Textile Coloration and Finishing
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• v.20 no.4
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• pp.43-52
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• 2008

Wool fabric was treated with oxygen low-temperature plasma (LTP) and dichloroisocyanuric acid. The effect of dimensional stability (relaxation shrinkage, hygral expansion, felting shrinkage), tensile strength and elongation, crease recovery, and hand of wool fabric between LTP, DCCA treated wool fabrics and control wool fabric were investigated. SEM photograph showed that a little micro crack was formed on the fiber surface by plasma treatment with hard condition and epicuticle scale was damaged by DCCA treatment. Felting shrinkage, tensile strength and total hand value were much different in each samples.