• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.208-211
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• 2005

This paper describes the development process of steering system for reduce idle vibration through the data level of frequency and sensitivity. High stiffness and light weight vehicle is a major target in the refinement of passenger cars to meet customers' contradictable requirements between NVH performance and fuel economy. The target frequency of the steering system is set by benchmarking of a competitive vehicle and the vibration mode map is used to separate steering column modes from resonance of body structure and engine idle rpm. This paper descirbes the analysis approach process for high stiffness of steering system and the design guideline is suggested about steering column and support system by using mother car at initial design stage. We used a patent map in order to analyze accurately a technical trend and suggested the design process using dynamic damper of steering system considering sensitivity. And we established techniques of analysis on steering system and evaluated the level of accuracy of analysis through correlating the test and analysis results. It makes possible to design the good NVH performance vehicle at initial design stage and save vehicles to be used in tests. These improvements can lead to shortening the time needed to develop better vehicles.

• YAKHAK HOEJI
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• v.30 no.6
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• pp.311-316
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• 1986

A new UV labeling reagent was developed and used in HPLC for the determination of prostaglandin $E_2$ which have weak UV light-absorbing property. This reagent, 2-bromoacetyltriphenylene, was synthesized by the bromination of 2-acetyltriphenylene which was obtained from triphenylene by Friedel-Crafts reaction. The wave length maximum (${\lambda}_{max}^{CH_3CN}$ of this reagent was 268nm. Prostaglandin E$_2$ was extracted from prostaglandin E$_2$-$\beta$-cyclodextrin using a Sep-pak $C_{18}$ cartridge. The prostaglandin E$_2$ was labeled with 2-bromoacetyl-triphenylene in aectonitrite using 18-crown-6-ether as catalyst. Derivatized prostaglandins were separated on a reversed-phase column (Radial-pak) $\mu$-Bondapak $C_{18}$ using acetonitrile: water=60:40 as mobile phase. The effluent was monitored by UV detector at 254nm filter kit. Linearity of calibration curve was obtained between 30ng and 140ng, and the lower limit of detection was 5ng.

• Korean Journal of Environmental Biology
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• v.25 no.1
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• pp.42-55
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• 2007

We investigated the species richness of lepidopteran insects (excluding butterflies and microlepidoptera) of Mt. Seungdal-san, Muan-gun, Jeollannam-do, Korea, from 2003 to 2005 using two portable light traps. A total of species comprised 423 species belongs to 17 families were identified. The family Noctuidae with 209 species was dominant in the area followed by Geometridae with 132 species. Based on the number of individuals collected, Geometridae was the highest mostly due to an ennomine species (Alcis angulifera). Monthly fluctuations of moth species richness present an M-shaped curve with two high peaks at June and August. Comparisons of species diversity of yearly captures revealed that the diversity of 2003 was higher than that of 2004, but the diversities of between 2003 and 2005, and between 2004 and 2005 were no different.

• Journal of The Korean Astronomical Society
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• v.37 no.1
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• pp.15-39
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• 2004

We analyse the results of mass models derived from the HI rotation! curves of spiral galaxies and find that the slope of the luminous mass-circular velocity relation is close to 4. The luminous mass-circular velocity relation with a slope of about 4 can be explained by an anti-correlation between the mass surface density of luminous matter and the mass ratio of the dark and luminous components. We also argue that the conspiracy between luminous and dark matter exists in a local sense (producing a flat or smooth rotation curve) and in a global sense (affecting the mass ratio of the dark and luminous matter), maintaining the luminous mass-circular velocity relation with a slope of about 4. We therefore propose that the physical basis of the Tully-Fisher relation lies in the luminous mass-circular velocity relation. While the slope of the luminous mass-circular velocity relation is fairly well defined regardless of the dark matter contribution, the zero-point of the relation is still to be determined. The determination of the slope of the Tully-Fisher relation needs one more step: the mean trend of the luminosity-luminous mass relation determines the overall shape (slope) of the Tully-Fisher relation. The key parameter needed to determine the zero-point of the luminous mass-circular velocity relation and the slope of the Tully-Fisher relation obviously is the luminous mass-to-light ratio.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.87.2-87.2
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• 2010

Near-Earth asteroid-comet transition object 4015 Wilson-Harrington is a possible target of the joint European Space Agency (ESA) and Japanese Aerospace Exploration Agency (JAXA) Marco Polo sample return mission. 4015 W-H was discovered showing cometary activity by Albert G. Wilson and Robert G. Harrington at Palomar Observatory in 1949. After recovered in 1979, 4015 W-H has been observed at every apparition, it always was seen as a point source. We made time series observations for 4015 W-H using the 1.8m telescope with 2K CCD at Bohyunsan Observatory, on the nights of 2009 November 17-19. The geocentric distance of 4015 H-W was about 0.38 AU at that time. No trace of cometary activity is seen from our images. From the light curve analysis, we find a double-peaked rotational period of 2.2 hours with amplitude of 0.4 magnitude. Our result is much shorter than previous measurements of 3.6 hours (Harris & Young 1983) and 6.1 hours (Osip et al 1995). We will discuss possible origin of the period variations.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.59.1-59.1
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• 2018

On 2018 February 5 a gamma ray burst with trigger time 04:25:29.3 UT was detected by Swift BAT and this event was named GRB 180205A. We observed the optical afterglow of GRB 180205A starting from about 1 hour after the burst until February 22 in the optical bands with the 1m telescope of Deokheung Optical Astronomy Observatory (DOAO), the 1m telescope at Mt. Lemmon Optical Astronomy Observatory(LOAO) and the 0.8m and 0.25m telescopes at McDonald Observatory. According to the fireball model, which is a well-accepted and conventional model for the afterglow of the GRB, the mechanism of the afterglow is that the expanding external blast wave of the GRB successively collides with the ambient medium and loses its energy, and as a result emits radiation at wavelengths longer than gamma rays. Here we present optical photometry and light curve of the afterglow in the R band and analyze it to characterize GRB 180205A.

• The Korean Fashion and Textile Research Journal
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• v.16 no.5
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• pp.791-799
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• 2014

For development of dyeability, the rayon fabrics were dyed repeatedly with persimmon juice by padding mangle. The merit of padding-based dyeing was easier color reproduction over traditional hand dyeing where various colors and color fastness to light and laundering are hard to obtain. We evaluated the mechanical properties and hand value by Kawabata Evaluation system for dyed rayon fabrics. The results obtained from this study were as follows. With the increase of repeating padding times of dyeing, the linearity load-extension curve and tensile energy per unit length of the rayon fabrics were increased, but the tensile resilience of fabrics were decreased. The value of shear stiffness and shear hysteresis were increased. Also compression resilience and linearity of compression thickness were increased. The rayon fabrics dyed with persimmon juice had shown the thickness and weight increase as the number of padding increase. As repeating times of dyeing with persimmon juice were increased, among the 6 hand values, the item of koshi(stiffness) and Hari(anti-drape stiffness), fukurami(fullness and softness) were increased. while Shinayakasa (flexibility with soft feeling) and Shari(crispness) were greately decreased. The amount of coated persimmon juice on the surface of the fabric was gradually increased as the padding times of dyeing.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.7 s.238
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• pp.930-937
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• 2005

One of the useful technology for light-weightening of components required in the automobile and machine industry is to use of high strength materials. To improve material properties, carbonizing treatment, nitrifying treatment, and shot-peening method are representatively applied, However, the shot-peening method is generally used to remove the surface defect of steel and to improve the fatigue strength on surface. Benefits by shot peening are to make increase resistance against fatigue, stress corrosion cracking, fretting, galling, erosion and closing of pores. In this paper, investigated the effect of shot peening on the corrosion of SUP-9 steel immersed in $3.5\%$ NaCl solution and corrosion characteristics by the heat treatment during shot peening process. The immersion test was performed on the four kinds of specimens. Corrosion potential, polarization curve, residual stress and etc. were investigated from the experimental results.

• Journal of the Korean Society of Costume
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• v.52 no.1
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• pp.21-36
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• 2002

The Miaos have their own unique and luxurious culture traditional and modern formed as they have experienced repeated fusion into and resistance against the Han Race or the Chinese in their long and old history. Taijiang County of Guizhou Provice, in which whey have been living, is endowed with natural beauty. Thus their culture enjoys abundant and diverse contents of artificial and natural character. Naturally, their costume reflects cultural and natural features in abundance and variety. This dissertation aims to investigate the artistic character of Miaos' traditional costume as reflected in patterns for their embroidery. As for the artistic character of the patterns for embroidery, the following were found. To begin with, the space in the Miaos' embroidery is, unlike the measurable three-dimensional space found in Greek art, unmeasurable and fantastic with its beauty, majesty and peculiarity. It is as if immersed in limitless space, they were in communion with gods and universe. Another characteristic is the use of image construction beyond mere imitation. Their mode of image construction was realistic in that patterns as a whole reveal an abstract form or meaning but separately they portray visual representations of concrete thins in nature. Still another is that sense of motion conveyed by the basic curve line is full of life. It was the result of using light rhythm breaking stereotypic balance and symmetry. Finally, the colouring was abstract, and a strong contrast between black and white was gorgeous and fantastic.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.2
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• pp.346-351
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• 1997

The creep characteristics of an Al-5wt.% Ag alloy including the stress exponent, the activation energy for creep and the shape of the creep curve were investigated at a normalized shear stress extending from $ 10^{-5}{\;}to{\;}3{\times}10^{-4}$ and in the temperature range of 640-873 K, where silver is in solid solution. The experimental results shows that the stress exponent is 4.6, the activation energy is 141 kJ/mole, and the stacking fault energy is $180{\;}mJ/m^2$, suggesting that the creep behavior of Al-5 wt.% Ag is similiar to that reported for pure aluminum, and that under the current experimental conditions, the alloy behaves as a class II(metal class). The above creep characteristics obtained for Al-5 wt.% Ag are discussed in the light of prediction regarding deformation mechanisms in solid solution alloys.