• Journal of the Korea Fashion and Costume Design Association
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• v.15 no.4
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• pp.129-142
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• 2013

Fabrics created unique features through the change in various ways depending on the elements including fabric structure, threads, thickness, weaving, patterns and processing. This study examined the difference between texture and image depending on components of fabrics. In order to understand the trend of components of fabrics, the actual components of fabrics was analyzed by year, using the women's apparel trend books, Nelly Rodi Fabrics and Promostyl Fabrics. This study analyzed Spring/Summer season and Fall/Winter season from 2002 to 2012. Frequency analysis, cross-tabulation analysis, multiple response cross tabulation analysis were implemented using SPSS 18.0. The followings are the analysis results. For fabric composition, Spring/Summer season used cotton fabric the most. Cotton fabric accounted for relatively high usage in 2005, 2007 and 2008. Fall/Winter season used wool the most in 2002, 2003, 2004 and 2005. In case of fiber blend by fabric composition, cotton was blended with other fibers in Spring/Summer season except wool. The fiber blending ratio of wool was the highest in Fall/Winter season. Wool was blended in most fabrics. More than two patterns were mixed for fabric patterns. The fabric patterns were applied the most in 2012. For fabric processing, the fabrics by sensitivity-functional processing were continuously used every year and the surface finish showed relatively high usage in 2002 and 2011. In conclusion, this study will build the systematic data for 11 years including fabric trends in the past. It can improve specialization, systematization and efficiency in fabric planning.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.1
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• pp.132-135
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• 2005

The purpose of this study was to propose the modified strip crown technique for esthetic restoration of primary anterior teeth using glass fibers. Celluloid crown form(3M, USA), Z100(P shade, 3M, USA). Aeliteflo(Bisco Inc., USA), and Clearfil SE Bond(Kuraray Medical Inc., Japan) were used for this technique. Mesh type of glass fiber(TESCERA Fiber Mesh, Bisco Inc, USA) was used for reinforcing material. After trimming the celluloid crown form, resin adhesive and flowable resin were applied on the pre-shaped glass fiber mesh. That mesh was placed on the lingual surface of inside of celluloid crown form and followed by light activation. Composite resin was filled into the celluloid crown form and put it on a prepared tooth and then light activated and finished the margin. The new modified strip crown technique can provide esthetics and increased durability for restoration of primary anterior teeth.

• Journal of the Korean Society of Costume
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• v.57 no.1 s.110
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• pp.93-104
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• 2007

This study is considered about the fabrics culture of Baekje Period by analyzing the fabrics pieces at a inner part of the It-bronze shoes found at the tomb of King Mu-ryeong in 1971 AD. The analysis methods of the fabrics pieces are a photographing of fabrics pieces surface by VMS, Digital camera(Nikon Coolpix 995) and the analysis of samples by SEM, XRD and FT-IR. It is assumed this fabrics pieces are the inner shoes, which consisted of compound woven silk at outward, some of tabby and a hemp at inward and the braids for decoration, of the gilt-bronze shoes. The features are as follows. 1. All of compound woven silk are the warp-faced compound tabby of plain fabrics and the density is various from high to low one. Compound woven silk which is attached the gilt-bronze shoes of the tomb of King Mu-ryeong weaves in high density by a thick thread. The fibers material of compound woven silk prove to be a silk by the analysis of wrap samples by SEM, XRD and FT-IR. 2. Tabby are excavated under the condition which attached on reverse side of compound woven silk. Those ran classify two types. First, the fine weaving by high density of wrap and weft. Second, the loose warp weaving with one warp and some of weft. 3. Hemp is almost ramie by SEM analysis and the density is different. Ramie which supposed to be attached Guem has the very low density. In addition to, Ramie pieces, excavated in condition and weaved finely, proved the conspicuous weaving skill in Baekje period. 4. Various kinds of braid are found and these ones classifies by fiber material and entwining way. Two types out of these are the one of silk thread, decorates the upper, middle parts of compound woven silk shoes and the other of hemp thread, decorates the lower parts.

• Composites Research
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• v.23 no.2
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• pp.10-16
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• 2010

$Al_2O_3$ fiber and SiC particle hybrid metal matrix composites (MMCs) were manufactured by squeeze casting method investigated for their tribological properties. The pin specimens had different ratios of fiber to particle content but their total weight fraction was constant at 20 wt. %. Tribological tests were performed with a pin-on-disk friction and wear tester. The investigation of the dry tribological characteristics of hybrid MMCs were carried out at room temperature and elevated temperature of$100^{\circ}C$ and$150^{\circ}C$. The morphologies of worn surfaces were examined by scanning electron microscope (SEM) to observe tribological characteristics and investigate wear behavior. The results revealed that the wear resistance improved with the content of SiCp increased of the planar random (PR) MMCs at room temperature. At the elevated temperature, it revealed that the wear resistance of normal (N) MMCs was superior to that of the PR-MMCs due to PR-fibers were easily pulled out holistically from the worn surface. Meanwhile, the coefficient of friction decreased with the temperature increasing.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1643-1646
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• 2003

Drawing is a mechanical operation that attenuates thick material to an appropriate thickness for the next processing or end usage. When the input material has the form of a bundle or bundles made of very thin and long shaped wire or fibers, this attenuation operation is called "bundle drawing" or "drafting" Drafting is being used widely in manufacturing staple yarns. which is indispensable for the textile industry. However, the bundle processed by this operation undertake more or less defects in the evenness of linear density. Such irregularities cause many problems not only for the product quality but also for the efficiency of the next successive processes. Since long there have been many researches tying to find out factors affecting the irregularity of linear desity, to obtain optimal drafting conditions, to develop efficient measuring and analysis methods of linear density of bundle, etc., but there exists yet no fundamental equation describing the dynamic behavior of the flowing bundle during processing. In this research a mathematical model for the dynamic behavior of the bundle fluid is to be set up on the basis of general physical lows representing physical variables, i.e. linear density and velocity as the dynamic state of bundle. The conservation of mass and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. On the basis of the simplified model, the simulation was performed and the results could be confirmed by the experiments under various conditions.

• Structural Engineering and Mechanics
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• v.58 no.1
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• pp.59-91
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• 2016

Laminated composite shells are commonly used in various engineering applications including aerospace and marine structures. In this paper, using semi-analytical finite strip method, the buckling behavior of laminated composite deep as well as thick shells of revolution under follower forces which remain normal to the shell is investigated. The stiffness caused by pressure is calculated for the follower forces subjected to external fibers in thick shells. The shell is divided into several closed strips with alignment of their nodal lines in the circumferential direction. The governing equations are derived based on first-order shear deformation theory which accounts for through thickness-shear flexibility. Displacements and rotations in the middle surface of shell are approximated by combining polynomial functions in the meridional direction as well as truncated Fourier series with an appropriate number of harmonic terms in the circumferential direction. The load stiffness matrix which accounts for variation of loads direction will be derived for each strip of the shell. Assembling of these matrices results in global load stiffness matrix which may be un-symmetric. Upon forming linear elastic stiffness matrix called constitutive stiffness matrix, geometric stiffness matrix and load stiffness matrix, the required elements for the second step analysis which is an eigenvalue problem are provided. In this study, different parameter effects are investigated including shell geometry, material properties, and different boundary conditions. Afterwards, the outcomes are compared with other researches. By considering the results of this article, it can be concluded that the deformation-dependent pressure assumption can entail to decrease the calculated buckling load in shells. This characteristic is studied for different examples.

• Korea-Australia Rheology Journal
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• v.14 no.3
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• pp.107-114
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• 2002

Residual stress distribution in injection molded short fiber composites is determined by using the layer-removal method. Polystyrene is mixed with carbon fibers of 3% volume fraction (4.5% weight fraction) in an extruder and the tensile specimen is injection-molded. The layer-removal process, in which removing successive thin uniform layers of the material from the surface of the specimen by a milling machine, is employed and the resulting curvature is acquired by means of an image processing. The isotropic elastic analysis proposed by Treuting and Read which assumes a constant Yaung’s modulus in the thickness direction is one of the most frequently used methods to determine residual stresses. However, injection molded short fiber composites experience complex fiber orientation during molding and variation of Yaung’s modulus distribution occurs in the specimen. In this study, variation of Yaung’s modulus with respect to the thickness direction is considered for calculation of the residual stresses as proposed by White and the result is compared with that by assuming constant modulus. Residual stress distribution obtained from this study shows a typical stress profile of injection-molded products as reported in many literatures. Young’s modulus distribution is predicted by using numerical methods instead of experimental results. For the numerical analysis of injection molding process, a hybrid FEM/FDM method is used in order to predict velocity, temperature field, fiber orientation, and resulting mechanical properties of the specimen at the end of molding.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.3 s.116
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• pp.47-60
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• 2006

This study was carried out to investigate the sheet formation properties of Morus Hanjis, made of bast and whole stalk pulps by different pulping methods, such as alkali, alkali-peroxide and sulfomethylated pulping. Two species of Morus, M. alba and M. lhou, were used. Effect of morphological properties of pulp stocks on the sheet formation and its gray levels based on optical property were evaluated using an Image analyzer. In addition, the effect of fiber distribution index(FDI) which was calculated from tile data of Confocal laser scanning microscopy(CLSM) on the sheet formation and optical properties of Morus Hanji were also discussed. On the sheet formation, Hanji from whole stalk pulp was superior than that of bast pulp. The more the sheet formation improved, the more paper opacity decreased. In the aspect of Hanji's surface characteristics analyzed by an Image analyzer, the average gray level and its standard deviation of Hanji from the whole stalk pulp were rather lower than those of bast pulp because of better sheet formation of the former. However, high brightness Hanji showed high value of gray level. The sheet formation and paper opacity were increased with the decrease of standard deviation of gray level. From these results, gray level measurement could be used to predict the paper opacity as well as sheet formation. Sheet formation of whole stalk Hanji and its FDI measured by CLSM were higher than those of bast fibers. In conclusion, the sheet formation and opacity of Hanji could be evaluated by standard deviation value of Hanji's gray level using an Image analyzer and by fiber distribution index using CLSM.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.4
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• pp.337-343
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• 2004

This paper presents an experimental study of friction and wear properties of a unidirectional oriented continuous crbon-fiber reinforced epoxy composite at the ambient temperature. Friction and wear experiments were conducted in the three principal sliding direction of the fiber orientation in the composite were selected against the stainless steel counterpart specularly processed were using a pin -on-disc apparatus. Friction coefficient and specific wear rate at various normal loads and sliding velocities wear determined. When sliding took place against smooth and hard counterpart, the hightest were resistance and the lowest friction coefficient were observed in the anti-parallel direction. The wear track of the worn specimens was examined with a scanning electron microscope(SEM) to observe the damaged fibers on the surface. In addition, SEM observations of the worn surfaces allowed to identify the involved different wear mechanisms.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.6
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• pp.365-371
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• 2019

In this study, the flame temperature distribution of the diffusion flame burner for SiO₂ deposition was analyzed by the computational fluid analysis. This corresponds to the previous step for simulating the SiO₂ preform deposition process for manufacturing optical fibers using environmentally friendly raw materials. In order to model premixed combustion, heat flow, convection, and chemical reactions were considered, and Reynolds-averaged Navier-Stokes equations and k-ω models were used. As a result, the temperature distribution of the flame showed a tendency to increase the distance from the nozzle surface to the maximum temperature when the flow rate of the auxiliary oxygen increased. In addition, it was confirmed that the temperature distribution due to incomplete combustion was large in the combustion reaction with a large equivalence ratio of the mixed gas.