• 한국초전도ㆍ저온공학회논문지
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• 제9권3호
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• pp.32-36
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• 2007

On the contrary of a conventional motor with very narrow air-gap. it is difficult to calculate the accurate magnetic field distribution and the performance of an air-cored superconducting motor by 2 dimensional analysis. which does not use high permeability material except outer machine shield. This paper aims to do analysis of magnetic field and force distribution from the 3 dimensional modelling of a 1MW class superconducting synchronous motor. Especially. the field coil composed of Bi-2223 high-temperature superconductor and the outer machine shield are modelled by finite element analysis software according to their structures and the self-inductance and Lorentz force are calculated based on the 3 dimensional magnetic field calculation. Moreover. the influence of an important parameter, synchronous reactance, has been analyzed on the machine performances such as voltage variation and output power.

• 대한설비공학회지:설비저널
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• 제13권4호
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• pp.215-222
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• 1984

An analytical study on the thermal instability of fluid in a vertical solt between two permeable walls has been carried out using fast converging power series solution method. For given values of prandtl number Pr and permeability paramter ${\sigma}$, the critical Grashof number $Gr_c$ and the critical wave number ac are found as eigenvalues of the problem formulated by the stability equations and the appropriate boundary conditions which are derived on the basis of linear stability theory. In the case of ${\sigma}\;>\;10^4$, the results approach those of solid boundary case, but in the case of ${\sigma}\;<\;10^3$, the decrease of $Gr_c$ and $a_c$become more prominent. In other words, the permeable walls cause the flow to be more unstable than the solid walls. This is considered to be due to the slip of the fluid on the wail, which decrease the friction force.

• 패션비즈니스
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• 제13권6호
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• pp.147-156
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• 2009

In this study, one of disadvantages is to improve the durability of natural dyeing. In order to enhance linkage of Chitosan or Linkage of between Chitosan and cotton fabrics, effect of increasing amount of Silane on Chitosan durability and possibility of using Chitosan as natural mordant were reviewed. After treatment of chitosan with silane, color effect is similar to dyeability used metal mordant. And the durability's washing fastness and air permeability as using chitosan with silane is better than treatment of metal mordant. Chitosan with silane can perform the natural mordant.

• KIEAE Journal
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• 제11권4호
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• pp.55-61
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• 2011

Due to global warming issues caused by climate changes which are internationally being highlighted, recently, there are lots of efforts under way to reduce energy consumption in various fields. Currently, 25 percent of energy consumption in Korea are being generated from buildings and especially, nearly 54 percent of them are being consumed by households. This study, therefore, aims to consider energy consumption status in the existing rural houses and analyze structure system performance, window system performance and air-permeability of domestic passive-type buildings using PHPP which is an analysis program of building energy to improve energy consumption problems in rural areas. Then, energy reduction plans in rural houses were proposed, by comparing and analyzing energy reduction of the existing rural houses, based on these data.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.202-206
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• 2001

The characteristics of heat transfer on the fire clay with microwave heating are numerically investigated using finite element method. The modelled regular hexahedron chamber($50cm{\times}50cm{\times}50cm$) filled with air consists of vertical heat source and sink walls, a fire clay model, and adiabatic plates at the top and bottom walls. With different geometrical aspect ratios of the fire clay model, the heat energy distribution is throughly investigated. The optimal shape of the fire clay for given chamber geometry and microwave power is analyzed.

• 패션비즈니스
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• 제11권4호
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• pp.92-100
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• 2007

The most emphasized materials in the modern fashion are the elastic materials with the advent of sportswear. In the area of elastic materials, the technology of foaming plastics became main research area. As novel materials, latex and neoprene based fabrics are emerging for the elastic material, among those elastic material staged by renowned fashion designers. We searched those works through literature and pictures, and examined the physical properties. Neoprene composite with filament knit fabrics are excellent in strength and water-proof. Latex fabrics gave smooth feel and elastic feel. These may be adequate for aesthetic textile material. Based on these characteristics, these techno-texitiles will find broad applications in the fashionable materials.

• 한국의상디자인학회지
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• 제4권1호
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• pp.99-110
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• 2002

This study is performed to investigate the effect of the mordant and chitosan on the colorfastness to laundering and physical properties of the mordanted, chitosan treated and natural - dyed cotton, silk and acrylics substrates. Natural dyes are extracted from Gromwell by boiled water. Three different compounds of Al, Cu, Sn and Chitosan are used as mordanting agents. The result of this study is summarized as follows: 1. Color of the fabrics dyed with Gromwell changes redder, bluer and darker after chitosan treated and mordanting. 2. After washing, the color of natural dyes changes more light and gray, Chitosan and Cu mordanting gives better colorfastness in washing than any others. 3. All chitosan treated fabrics improve air permeability. 4. In the chitosan treated fabrics, a half life of the static electricity is shown good result.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.246-250
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• 2001

In resin transfer molding (RTM), resin is forced to flow through the fiber perform of inhomogeneous permeability. This inhomogeneity is responsible for the mismatch of resin velocity within and between the fiber tows. The capillary pressure of the fiber tows exacerbates the spatial variation of the resin velocity. The resulting microscopic perturbations of resin velocity at the flow front allow numerous air voids to form. In this study, a mathematical model was developed to predict the formation and migration of micro-voids during resin transfer molding. A transport equation was employed to account for the migration of voids between fiber tows. Incorporating the proposed model into a resin flow simulator, the volumetric content of micro-voids in the preform could be obtained during the simulation of resin impregnation.

• 펄프종이기술
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• 제34권1호
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• pp.7-11
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• 2002

The print quality of a ink jet printer is generally affected by three major components of the printing process: printer, ink formulation, and paper. The result of this study indicated that the surface sized paper with oxidized starch and cationic starch differed ink jet print quality in terms of ink spread and black optical density of the print image. Paper properties, like air permeability and siting degree, which may influence the ink jet printing were also measured. It was found that black print quality was controlled by starch level and ionic charge on the paper surface. Cationic surface sizing starch improved black ink jet print quality.

• 멤브레인
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• 제7권1호
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• pp.22-30
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• 1997

Porous asymmetric membranes were prepared from polyetherimide polymer by the phase-inversion technique under different conditions. The performance of the membranes was tested for the removal of acetone vapour from nitrogen. A membrane which showed a high acetone permeability and a high selectivity was chosen and tested further for the separation of different organic vapours from nitrogen. The molecular structure of organic vapours and the selectivity were correlated. A strong correlation was also found between the chromatographic retention time of the organic vapour and the selectivity. These experimental results led to the conclusion that the sorption is the factor governing the separation of volatile organic compounds from nitrogen. A membrane was also prepared by coating the surface of a porous polyetherimide membrane with silicone rubber. The performance of membranes with and without silicone rubber coating was compared.