• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.392-392
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• 2011

Carbon nanotubes (CNT) emitter has widely become an attractive mechanism that draws growing interests for cold cathode field emission.$^{1,2}$ CNT yarns have demonstrated its potential as excellent field emitters.$^3$ Extensive simulations were carried out in designing a CNT yarn-based cathode assembly. The focal spot size dependence on the anode surface of the geometric parameters such as axial distance of the electrostatic focus lens from the cathode and the applied bias voltages at the cathode, grid mesh and electrostatic focus lens were studied. The detailed computer simulations using Opera 3D electromagnetic software$^4$ had revealed that a remarkable size of focal spot under a focusing lens triode type set-up design was achieved. The result of this optimization simulation would then be applied for the construction of the CNT yarn based micro-focus x-ray tube with its field emission characteristics evaluated.

• The Research Journal of the Costume Culture
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• v.17 no.4
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• pp.723-732
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• 2009

The quick response(QR) system is very popular in Korean apparel companies. However, the usage of QR system was not known well. The purpose of this study is to identify the usage of the quick response decision support system(QR DSS) and postponement manufacturing in the Korean apparel company. The researched company was the only one which used the QR DSS. The researchers carried out the depth interview with the QR decision makers of the company. This company had 14 brands, and had used the QR DSS since January, 2008. The results are as follows: The QR DSS was supportive computer software program, and it helped the staffs to make agile decision about QR repeat production of clothing. The QR DSS automatically calculated the related data, and suggested the expected sales volume and the proper supply amounts of the styles. There were four functions in QR DSS : 'QR Alert', 'Proper Supply Amount Simulation', 'Sensible QR', and 'Supply/Sales Simulation by Item'. The men's clothing brands effectively used 'Supply/Sales Simulation by Item' function. And the women's clothing brands effectively used 'QR Alert' function. This company also used the postponement production system for QR repeat production. The postponement production was conducted with four methods : the yarn stocking, the grey fabric stocking, the dyed fabric stocking, and the fabric sourcing. The men's clothing brands usually used of the yarn stocking methods and the dyed fabric stocking methods. The women's clothing brands usually used the grey fabric stocking methods. By using QR DSS and postponement production system the company was able to shorten the lead time for QR decision making.

• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.359-363
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• 2013

Silicon carbide and its composites are being considered as a nuclear fuel cladding material for LWR nuclear reactors because they have a low neutron absorption cross section, low hydrogen production under accident conditions, and high strength at high temperatures. The SiC composite cladding tube considered in this study consists of three layers, monolith CVD SiC - $SiC_f$/SiC composite -monolith CVD SiC. The volume fraction of SiC fiber and surface roughness of the composite layer affect mechanical and corrosion properties of the cladding tube. In this study, various types of SiC fiber preforms with tubular shapes were fabricated by a filament winding method using two types of Tyranno SA3 grade SiC fibers with 800 filaments/yarn and 1600 filaments/yarn. After chemical vapor infiltration of the SiC matrix, the surface roughness and fiber volume fraction were measured. As filament counts were changed from 800 to 1600, the surface roughness increased but the fiber volume fraction decreased. The $SiC_f$/SiC composite with a bamboo-like winding pattern has a smaller surface roughness and a higher fiber volume fraction than that with a zigzag winding pattern.

• Fashion & Textile Research Journal
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• v.5 no.3
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• pp.299-303
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• 2003

Some of historical textiles were analyzed to identify the imprinted textures on the metal remains of Haengyeup(a horse strap pendant) and Doja (a knife), which were excavated in the ruins of Hwangsung-dong, Kyungju city in the fifth century and textiles imprinted on the human bones that were excavated in the Pungnae 4th Area, Namyangju county in the sixteenth century. The results analyzed arc as follows ; It was confirmed that the imprinted textures of Haengyeup and Doja are white ramie since the structural characteristics of cellulosic bast fibers, partially projected long oval cross sections with large lumens and the imprinted textures of human bones are silk fabrics since the triangular cross sections of fibroin is showed. All of the textiles were designed in plain weaves. In the case of weaving yarns, the warp threads were thicker than the weft threads, that is, the imprinted textures of Haengyeup were measured by 1.35 mm for warp and 1.21 mm for weft, and the Doja by 1.16mm for warp and 1.11 mm for weft. In connection with the direction of the yarn twist, the Z-twist were observed in the imprinted textures of human bones, whereas it presented the S-twist in the case of Haengyeup and Doja. The warp yarns were mostly harder twisted than the weft yarns on the amounts of twist, that is, it was observed that the case of Haengyeup were amounted to 0.33 twists per centimeter for warp yarns and 0.25 twists per centimeter for weft yarns. Also it was showed 0.32 twists per centimeter for warp yarns and 0.26 twists per centimeter in the case of the textures of human bones. On the fabric counts, it was showed that the finer the yarns the higher the densities since it were $4.3{\times}5.1$ threads per sqaure centimeters and $7.6{\times}7.1$ threads per sqaure centimeters each in the case of Haengyeup and Doja, whereas it was $18.2{\times}33.7$ threads per sqaure centimeters in the case of the textures of human bones.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.939-941
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• 2017

The use of composites is increasing for lightweight aerospace structures. Among these structures, the ring frame and the parts of the projectile body are mainly made of a fiber reinforced composite material which is less susceptible such as delamination to structural damage. As the use of fiber reinforced composites increases, interest in modeling efficient methods of stiffness and strength is increasing. This paper predict the mechanical strength according to the repeating unit cell(RUC) of the 2-D triaxial braided composites of fiber reinforced composites. Yarn slice definition, incremental approach and stiffness reduction model were used as strength prediction. Finally, the results of strength prediction are verified by comparing with experimental data of 2-D triaxial braided composites specimens.

• Journal of Fashion Business
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• v.18 no.3
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• pp.73-90
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• 2014

Paper, once known and used only as a medium for printing or handicrafts, is now being used in new fields including artistic clothing, and an environment-friendly material for fashion, while the functionality of its formative characteristics and esthetics have been newly highlighted. On this basis, this study performed a content analysis of paper couture and categorization of types of paper modeling techniques based on 904 paper couture submitted to paper fashion shows, exhibitions and contest exhibits from 2001 to 2013. Analysis results showed that paper textile types were most common at 86.64%, while techniques using laminating, bonding, overlapping or paper as-is represented 62.17%. Expressive techniques in which paper was cut or torn and attached to paper clothing was 11.62%, paper folding was 5.75%, drawing and coloring 4.65%, and finally, paper cutting was 2.65%. Meanwhile, among paper modeling techniques using paper yarn textiles, a paper weaving technique was 6.75%. Moreover, other techniques in which paper modeling techniques or subsidiary clothing was blended were 3.65%, and Dak peeling textiles were 1.33%. Paper paste moulding textiles types represented 1.44%, above all papier $m{\hat{a}}ch{\acute{e}}$ techniques of 0.55% and creasing and holding techniques were 0.88%. Paper is sufficient to express the artists' creativity as well as having qualities as an artistic medium, such as variability through combined use with other materials, variation in form, suitability for reuse of waste paper, and environmental friendliness. Also, various paper modeling techniques can be blended with textiles for a generalized technology that overcomes the limits of paper and textiles.

• Journal of Fashion Business
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• v.23 no.2
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• pp.156-169
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• 2019

The objective of this study was to develop lightweight, stretchable, tight-fit smart sportswear using the conductive yarns into the garment and demonstrating its usefulness. Sportswears with the ability to control LEDs with respect to lighting of the surrounding were developed by applying embroidery with conductive yarns to 2 types of men's T-shirts and 2 types of women's leggings pants for outdoor activities and exercise purposes. LEDs were applied to the front and back of men's T-shirts and to the rear of the waist of women's leggings. Men's T-shirts were printed where the LEDs were to be applied, and inside, they were embroidered with conductive threads on the hot-melt fabric to be attached, and then connected with LED. Women's pants were embroidered on the elastic band, in the form of a sine wave that gives it ability to stretch, and finally the elastic band was hidden inside the waistband. The operation of the light sensor in the dark provided the ability to protect joggers from night drivers or cyclists. LEDs were activated when the wearer turns on the fashionable device on his/her shoulder by pressing it. It was able to reduce the risk of accidents by giving recognizability to vehicles, bicycles, and athletes approaching or passing by at night, and securing safe distance from vehicles, etc. Internal embroidery technology had the same flexible and lightweight functions as ordinary clothing products, making it possible to apply to tight-fit smart T-shirts or leggings pants designs.

• Textile Coloration and Finishing
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• v.35 no.2
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• pp.128-136
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• 2023

Recently, the automobile industry is developing as the demand for automo- biles increases due to industrial development and population growth. In addition, many studies are being conducted to reduce heat loss inside the automobiles in order to save energy inside the automobiles due to environmental regulations. In this study, alumina, nanosilicon, and aerogel, which are adiabatic materials, were filled in PET to manufacture yarn, identify physical and mechanical properties, and weave into fabric to confirm adiabatic performance. As the content of the adiabatic material increased, the tensile strength of the fibers filled with alumina and nanosilicon decreased greatly, and the adiabatic property slightly increased. The tensile strength of fibers filled with the aerogel decreased slightly, but the adiabatic properties were greatly increased. Therefore, it is considered to be due to the large volume fraction in the PET yarn due to the low density of the aerogel.

• Fibers and Polymers
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• v.7 no.4
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• pp.420-423
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• 2006

Spandex has been successfully applied on modified worsted spinning system to produce spandex core spun yam. However it's difficult to produce wool/spandex core-spun yam on woolen spinning system with the same modified device because the drafting device of the two systems is quite different. A new method is introduced to apply spandex on woolen spinning system in this paper. Core-spun yam produced in this way has good appearance and quality by comparing with normal yam. A series of experiments were carried out to study the influence of spandex drafting ratio and yam twist factor on tensile' properties and elasticity of core-spun yams. The results indicate that core-spun yam with spandex drawing ratio of 2.5 and twist factor of 13.63 has highest value of tenacity and breaking elongation.

• Fibers and Polymers
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• v.4 no.2
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• pp.84-88
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• 2003

The properties of a woven fabric made of poly(trimethylene terephthalate) (PTT) were investigated. The PTT fab-ric of draw textured yarn (DTY) showed excellent stretch as good as a fabric containing spandex. However, the unique stretch of the PTT fabric reduced dramatically by simple heat-treatment even at as low as $80^{\circ}C$. To understand the phenomenon, the crimp rigidity of the DTY was observed by SEM. It was found that the drastic reduction of stretch was caused by irreversible uncrimping of PTT DTY after heat-treatment. Conclusively, it is of importance to optimize the texturing conditions for PTT DTY to make the crimp more stable.