• Tribology and Lubricants
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• v.14 no.1
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• pp.85-93
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• 1998

The Bair & Winer's limiting shear stress rheological model is incorporated into the Reynolds equation to successfully predict the traction and film thickness for an isothermal line contact using the primary rheological properties. The modified WLF viscosity model and Barus viscosity model are also adapted for the realistic prediction of EHD tractional behavior. The influences of the limiting shear stress and slide-roll ratio on the pressure spike, film thickness, distribution of shear stress and nonlinear variation of traction are examined. A good agreement between the disc machine experiments and numerical traction prediction has been established. The film thickness due to non-Newtonian effects does not deviate significantly from the fdm thicknesss with Newtonian lubricant.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.6
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• pp.577-582
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• 2003

This paper describes a new technique for thickness measurement of a very thin layer less than one-quarter of the wavelength of ultrasonic wave used in the ultrasonic pulse-echo measurements. The technique determines the thickness of a thin layer in a tapered medium from constructive interference of multiple reflection waves. The interference characteristics are derived and investigated in theoretical and experimental approaches. Modified total reflection wave g(t) defined as difference between total and first reflection waves increases in amplitude as the interfacial layer thickness decreases down to zero. A layer thickness less than one-tenth of the ultrasonic wavelength is measured using the maximum amplitude of g(t) with a good accuracy and sensitivity. The method also requires no inversion process to extract the thickness information from the waveforms of reflected waves, so that it makes possible to have the on-line thickness measurement of a thin layer such as a lubricating oil film in thrust bearings and journal bearings during manufacturing process.

• Journal of Fashion Business
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• v.12 no.4
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• pp.143-157
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• 2008

The purpose of this study was to evaluate the visual effects and images according to changes in the silhouettes and length of miniskirt. The silhouettes of the miniskirt were classified into two different categories according to side line, H-line and A-line. We altered the length of the miniskirt in five categories with changes in 25cm, 27.5cm, 30cm, 32.5cm, and 35cm. For the visual evaluation, 10 stimuli were placed in mannequins, and were estimated by the experts in the fashion design. For the visual evaluation according to changes in the silhouettes and length of the miniskirt, we used 13 pairs of items to find the visual effects, and 23 pairs of adjectives to measure the visual images. The stimuli and adjectives were randomly given to the evaluators and were evaluated by the 7-Point Likert Type Scale. The data have analyzed by frequency, t-test, factor analysis, anova, scheffe's test and the MCA method. According to the factor analysis of the visual effects of the miniskirt, the result was classified into 3 factors: the thickness of the lower body, the length of the lower body, and the shape of the lower body. According to factor analysis of the visual image of the miniskirt, the result was classified into 4 factor: personality, attraction, elegance, and activity. The silhouettes of miniskirt had more positive visual effects and images in A-Line than in H-Line. Among the visual effects of miniskirts, the length affected the thickness and length of the lower body more than the silhouette did and, the silhouette had more effects on the shape of the lower body than the length did. And shorter the skirts, stronger the image of personality. However, 32.5cm and 35cm miniskirts are estimated to be more attractive than excessively short skirts. There are many differences in the image of personality and activity according to the changes in the length of miniskirts.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.17 no.1
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• pp.13-18
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• 1981

Corrosion loss of the shell plates of the steel vessels are measured and analyzed on the thirty cargo vessels and fifteen lumber carriers of which nationality belong to Korea. Thickness of the shell plates were determined at the every observed points set along the fore and aft line and perpendicular to it, by use of the ultrasonic thickness meter. Difference of the thickness between the original and the determined shell plates are given as the corrosion loss at the present age. The results obtained are summarized as follows: 1. On the cargo vessels, (1) The total mean of the corrosion loss is greatest at the light waterline, in every age class of the vessels. (2) The total mean of the corrosion loss on the fore and aft line shows little difference, even though it is slightly greater at the fore part, in every age class of the vessels. (3) Corrosion loss along the perpendicular line grows greater in the order of freeboard, load waterline, upper bilge line and light waterline, within the 16 of the age of the observed vessels. Its order varies to freeboard, upper bilge line, load waterline and light waterline in the age of 35. Corrosion loss at the light waterline and load waterline, in the age of 35, shows 3 times of it at the freeboard, and it at the upper bildge line shows twice of it at the freeboard. The fact significates the corrosion grows rapidly around the waterline. 2. On the lumber carriers, (1) The total mean of the corrosion loss is greatest at the upper bilge line, in the every age class of the vessels. (2) Total mean of the corrosion loss on the fore and aft line shows little difference, even though it is slightly greater at the fore part, in every age class of the vessels. (3) Corrosion loss along the perpendicular line is least at the freeboard and greatest at the upper bilge line, and its value at the upper bilge line shows twice of it at the freeboard. 3. The total mean of the corrosion loss of the lumber carriers shows almost twice of the cargo vessels.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.1
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• pp.20-26
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• 1986

In this paper, the Bilateral Fin-Line structure is analyzed by Rayleigh-Ritz variational method including the effects of conductor thickness. Bilateral Fin-Line bandpass filters are realized at X-Band. Experimental results are in good agreement with the theory.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.415-418
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• 1995

This paper describes a new technique for thickness measurement of a very thin layer less than one-quarter of the wavelength of ultrasonic wave using ultrasonic pulse-echo method. The technique determines the thickness of a thin layer in a layered medium form the amplitudes of the total reflected waves from the back side layer of interst. Thickness of a very thin layer few inch deep inside the media can be measured without using a very high frequency ultrasonic transducer over 100MHz which must be used in the conventional techniques for the precision measurement of a thin layer. The method also requires no inversion process to extract the thickness from the waveform of the reflected waves, so that it makes possible on-line measurement of the thickness of the layer.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.4
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• pp.9-17
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• 1994

Effect of Newtonian and non-Newtonian oils on minimum ol film thickness in engine journal bearing were investigated at various oil viscosities. The influence of oil viscosity and engine operating conditions on minimum oil film thickness of main bearing and con-rod bearing was examined. Minimum oil film thickness for Newtonian oils increased uniformly with kinematic viscosity. But the correlation between kinematic viscosity and minimum oil film thickness was very poor for non-Newtonian oils. According to the straight-line regression analysis for non-Newtonian oils, high temperature high shear viscosity at 1 $1{\times}10^6Sec^{-1}$, $150^{\circ}C$ increase the coefficient of determination from 0.41 to 0.77. Con-rod bearing showed better correlation between minimum oil film thickness and engine operating conditions than main bearing.

• Journal of Fashion Business
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• v.16 no.5
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• pp.57-73
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• 2012

The main objective of this research was to understand the characteristics of pleats design through the analysis of modern female fashion as they appear in the 'Collections' from '09 A/W to '12 S/S. Data collection of 1027 was done through the review of 'pr$\hat{e}$t-$\grave{a}$-porter Collections' of three cities; Milan, New York, Paris. Along with the qualitative interpretation of pleats design, statistical analysis of frequency and ${\chi}^2$-test were completed for data analysis. The main findings were as follows; 1. The five types of pleats design were founded in the order of accordion, knife, box, inverted, and sunburst pleats. The frequency and ratio of pleats design occurency showed significant difference between collections. 2. There were significant difference between the types of pleats and their line characteristics of thickness, continuity, length, direction. = Thin fabrics with delicate fine folds were mainly appeared in accordion and sunburst pleats. On the other hand, midium thickness fabrics were used for knife, box & inverted pleats, however, the different images were projected according to the width and the number of folds, characteristics of fabrics and textures. = In all the type of pleats but sunburst, continuity line was appeared the most. The discontinuous lines were appeared the most in the layered types and, sometimes, at some construction lines to add some decorative details or design variations. = The long line were the most frequently appeared in long one-pieces or long skirts of knife, accordion, sunburst pleats. While, the shorter lines showed the most frequently in box and inverted pleats, which mainly used for skirts or the lower part of one-piece. = For the line directions, the vertical lines were the most frequently appeared, and followed by mixed and diagonal line. In mixed or diagonal lines, same type of pleat was repeated in one design. For diagonal lines, one direction was mainly used, however, the symmetrical arrangements or repeated diagonal pleats in various directions also used. In mixed lines, the type of one or two diagonal and one vertical line was the most frequently appeared.

• 연구논문집
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• s.32
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• pp.65-76
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• 2002

The intensity of x-ray or gamma-ray is attenuated according to density and thickness of the transmitted medium. In this study, by using this principle, on-line real-time radiometric system was developed using a 128 channels linear array of solid state detectors to measure wall thickness of insulated piping system. This system uses a Ir-192 as a gamma ray source and detector is composed of BGO scintillator and photodiode. Ir-192 gamma ray source and linear detector array mounted on a computer controlled robotic crawler. The Ir-192 gamma ray source is located on one side of the piping components and the detector array on the other side. The individual detectors of the detector array measure the intensity of the gamma rays after passing through the walls and the insulation of the piping component under measurement. The output of the detector array is amplified by amplifier and transmitted to the computer. This system collects and analyses the data from the detector array in real-time. The maximum measurable length of pipe is 120cm/mm. in the case of 1mm scanning interval.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.364-367
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• 2007

In nano-imprint lithography (NIL) process, which has shown to be a good method to fabricate polymeric patterns, several kinds of pattern defects due to thermal effects during polymer flow and mold release operation have been reported. A typical defect in NIL process with high aspect ratio and low resist thickness pattern is a resist fracture during the mold release operation. It seems due to interfacial adhesion between polymer and mold. However, in the present investigation, FEM simulation of NIL molding process was carried out to predict the defects of the polymer pattern and to optimize the process by FEA. The embossing operation in NIL process was investigated in detail by FEM. From the analytical results, it was found that the lateral flow of polymer resin and the applied pressure in the embossing operation induce the weld line and the drastic lateral strain at the edge of pattern. It was also shown that the low polymer-thickness result in the delamination of polymer from the substrate. It seems that the above phenomena cause the defects of the final polymer pattern. To reduce the defect, it is important to check the initial resin thickness.