• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.156-160
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• 1994

Use of engineering ceramics has been increasing due to the outstanding physical and chemical properties. Conventional machining processes, however, are not applicable due to their hardness and brittleness. Laser cutting is a promising alternative for these ceramics. In this study, experimental data of CO $_{2}$ laser cutting of $Al_{2}$ $O_{3}$ and Si $_{3}$ N $_{4}$ are obtained to give a guide in the industry. Results of $Al_{2}$ $O_{3}$ cutting showed extreme weakness to thermal crack and it was found that pulsed beam has to be used for thick $Al_{2}$ $O_{3}$ specimen. Si $_{3}$ N $_{4}$ showed good results for both CW and pulsed beams. Using pulsed beam resulted narrower kerf width with increased surface roughness a nd reduced cutting speed. It was also found that a parameter call path energy is useful for representing minimum threshold value for possible cutting range with pulsed beam.

• Journal of Environmental Science International
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• v.13 no.4
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• pp.403-412
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• 2004

Waste water-soluble cutting oil was treated with WI type #1 and WI type #2. The properties of the original water-soluble cutting oil were pH=l0.4, viscosity=1.4cP, CODcr=44,750 ppm, and TOC=10,569 ppm. However, the properties of the oil used for more than 3 months were changed to pH=7.82, viscosity=2.1cP, CODcr=151,000 ppm, and TOC=74,556 ppm. It might be attributed to the fact that molecular chains were cut due to thermal oxidation and impurities such as metal chips were incorporated in to the oil during the operation processes. To prevent the putrefaction of oil, the sterilization effect of ozone and UV on the microorganism in the oil was investigated. Ozone treatment showed that 99.99% of the microorganism was annihilated with 30 minutes contact time and 60 minutes were necessary for the same effect when UV was used. Ozone treatment could cut molecular chains of the oil due to strong sterilization power, which was evidenced by the increase of TOC from 25,132 ppm at instantaneous contact to 28,888 ppm at 30 minutes contact time. However, UV treatment didn't show severe changes in TOC values and thus, seemed to cause of severe cut of molecular chains. When the activated carbon was used to treat the waste water-soluble cutting oil, TOC decreased to 25,417 ppm with 0.lg carbon and to 15,946 ppm with 5.0g carbon. This results indicated that the waste oil of small molecular chains could be eliminated by adsorption. From the results, it could be concluded that these treatment techniques could be proposed to remove the waste oil of small molecular chains resulting in the degradation of the oil properties. In addition, these experimental results could be used for the correlation with future works such as investigation of the molecular distribution according to the sizes, lengths, and molecular weight of the chains.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.2
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• pp.16-22
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• 2006

This study was carried out to estimate the physical and chemical soil characteristics in highway cutting slope areas. The soil was sampled in cutting area and natural vegetation area that was located in the upper areas of the highway cutting slope. The average total soil depth, bulk density, and soil hardness were bad in the highway cutting slope sites. The sandy loam was the most soil texture in the study area. The concentration of soil organic matter and nitrogen were very low in all highway cutting areas. The concentration of exchangeable cations was similar between the highway cutting slope and the natural vegetation sites in each highway. The soil pH was higher in highway cutting slope areas than in natural vegetation sites. In conclusion, chemical and physical properties of soil were bad in the cutting slope than in the natural vegetation area because of the loss of soil by cutting of slope area and less organic matter input by less vegetation in the highway cutting slope area. We should employ possible method to reduce the loss of soil, and compost and fertilization treatment could help to increase soil nutrient content in the cutting slope area.

• Journal of the Korea Furniture Society
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• v.16 no.1
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• pp.17-23
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• 2005

European maple is famous for the optimum solid wood for making bridge which is the most important part in violin acoustics. This study was carried out to investigate the variation of main features, i. e. annual ring width and cutting direction of costly imported violin bridge blanks and to examine the effect of these features of the blanks on the vibrational characteristics of bridge blanks. Imported violin bridge blanks had somewhat large variation in major macroscopical and physical properties and there was little relationship between annual ring density and weight of maple blanks. Resonant frequency of violin bridge blanks had some positive correlation with weight, however, damping having negative relationship with frequency was seldom affected by any physical properties of the maple blanks. Deviation from the radial cutting of tail side(ray direction from top toward feet on the edge of bridge blank) lowered the resonant frequency. Consequently, weight and ray direction should be taken for the critical quality decisive factors(QDF) of incoming bridge blanks by not only inspectors also luthiers who tune the bridge by shaping and are responsible for the final timbre quality of this complicate instrument.

• Korean Journal of Agricultural Science
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• v.43 no.2
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• pp.240-248
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• 2016

Radish is a common vegetable consumed in Korea, Japan, and China. Radish Breeding has been conducted based on morphological properties, such as shape and color. Recently, physicochemical properties of radish are attracting more attention from breeders to develop cultivars for the retail market. In this study, major components of radish were determined and their relationship with textural property analyzed. Sixty-six radish cultivars were selected and divided into white head (WH) and green head (GH) according to their head color. The cutting forces of GH and WH groups were $2.17{\pm}0.34kg$ and $2.31{\pm}0.36kg$, respectively (P > 0.05). The starch contents of GH and WH were $3.75{\pm}0.39g\;per\;100g$ (dry basis) and $4.24{\pm}0.62g$, respectively. Cellulose contents in both groups were similar at 12.3-12.4 g per 100 g (dry basis). Pearson correlation coefficients between cutting force, cellulose content, and starch content ranged from -0.33-0.326 which does not demonstrate any strong correlation between these components. Therefore, no relationship was found between the cutting force and the starch content or the cellulose content for the cultivars analyzed in this study. As the first intensive study on the texture and the major components of radish, these results could provide valuable information for radish breeding if further studies on taste and nutrient components are conducted.

• Journal of the Semiconductor & Display Technology
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• v.17 no.3
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• pp.53-58
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• 2018

The modern industry requires the precision machining as well as the high productivity. The machine tool structure should be evaluated in aspects such as durability, static stability, precision rate and the dynamic stability which is one of the most critical characteristics in determining the magnitude of vibrations. In this study, the dynamic properties of a pipe cutting machine were investigated to analyze the structural vibrations of the machine, and further to improve the structural stability and precision machining. Frequency response test and computer simulation have been utilized for the analysis and the design alterations. And the result shows that proposed design alterations can reduce the vibrations of the machine substantially.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.1
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• pp.65-72
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• 2005

Drilling process is one of the most common, yet complex operations among manufacturing processes. The performance of a drill is largely dependent upon drilling forces, Many researches focused on the effects of drill parameters on drilling forces. In this paper, an effective theoretical model to predict thrust and torque in drilling is presented. Also, with the predicted forces, the stress analysis of the drill tool is performed by the finite element method. The model uses the oblique cutting model for the cutting lips and the orthogonal cutting model for the chisel edge. Thrust and torque are calculated analytically without resorting to any drilling experiment, only by tool geometry, cutting conditions and material properties. The stress analysis is performed by the commercial FEM program ANSYS. The geometric modeling and the mesh generation of a twist drill are performed automatically. From the study, the effects of the variation of the geometric features of the drill and of the cutting conditions of the drilling on the drilling forces and the stress distributions in the tool are calculated analytically, which can be applicable for designing optimal drill geometry and for improving the drilling process.

• Journal of Fashion Business
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• v.19 no.4
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• pp.109-119
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• 2015

A wide variety of fashion materials focus on good drape property and softness. Among the recently emerging materials, Neoprene that consists of laminated knit on both sides of foamed neoprene sheet seeks a unique appearance that is considerably deviated from the current flow. Diverse processing methods for the newly released material heighten the value in function and beauty among trends of fashion materials by enhancing the appearance, touch and material property. Laser-cutting technique is one of the processing methods that is consistently used in the textile area. This study aimed to find the basic materials for applicability of laser-cutting technique to clothing goods after consideration of the changes in material property and drape shape, and to furthermore enforce different pattern conditions to Neoprene material, one of the newly attractive materials in the fashion area. In this study, we applied laser-cutting technique to Neoprene material sample under different conditions of pattern appearance, size and distance, based on current evaluation and theoretical background of Neoprene material, fashion trend and laser-cutting technique. Drape property can improve and the drape direction could also be controlled by a wide variety of laser-cutting techniques applied to Neoprene materials that have uniquely different appearances from most other textiles. This technique could be applied to the design for diversification of Neoprene clothing goods in the future.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.2
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• pp.196-205
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• 2004

The cutting characteristics and the deformed layer of nitrogen(N)-added type 316LN stainless steel were comparatively investigated to type 316L stainless steel. The cutting force, the surface roughness(Ra) and the tool wear in face milling works were measured with cutting conditions, and the deformed layers were obtained from micro-hardness testing method. The cutting resistance of type 316LN was similar to type 316L in spite of its high strength. The surface roughness of type 316LN was superior to type 316L for all the cutting conditions. In particular, in the high cutting speed above 345m/min, the surface roughness of the two stainless steels was closely same. The deformed layer thickness of the two stainless steels was generated in the 150$\mu\textrm{m}$-300$\mu\textrm{m}$ ranges, and its value of type 316LN was lower than that of type 316L. This is due to the high strength properties by nitrogen effect. It was found that type 316LN was higher in the tool wear than that type 316L, and flank wear was dominant to crater wear. In face milling works of type 316LN steel, tool wear is regarded as a important problem.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.135-140
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• 2001

In metal cutting at the tool-chip interface, friction generates considerable amount of heat. Thus, tile .knowledge of wear properties or the cutting tool material in high temperature has been known as one of tile important factors in need of clarification. The authors presented the wear properties of 5%V-5%Co-1%Nb high speed steel, fabricated by powder metallurgy, in room temperature in a previous article. The objective of this paper is to clarify tile effects of temperature ell its wear properties. Wear tests in sliding conditions under various temperatures have been conducted. The results indicate that tile wear properties of tile tool material in high temperature as well as in room temperature are excellent. It may be deduced that the oxide layer formed on the vol-n surface at high temperature is stable enough to prevent wear due to tile high temperature strength of its matrix.