• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.214-217
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• 2002

Micro Surface Electrochemical Machining has traditionally been used in highly specialized fields such as those of the aerospace and defense industries. It is now increasingly being applied in other industries where parts with difficult-to-cut material, complex geometry and tribology such as compute. hard disk drive(HDD) are required. Pulse Electrochemical Micro-machining provides an economical and effective method for machining high strength, high tension, heat-resistant materials into complex shapes such as turbine blades of titanium and aluminum alloys. Usually aluminum alloys are used bearings to hard disk drive in computer. In order to apply aluminum alloys to bearing used in hard disk drive, this paper presents the characteristics of Micro Surface Electrochemical machining for aluminum alloy.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.1
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• pp.93-103
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• 1997

The purpose of this study was to investigate the actual performance of Korean firefighter's clothing through comparisons with protective clothing used in the United State, surveys of firefighter's opinion, and experiments on the material used in Korean firefighter's clothing. The paper presents experimental results as well as ways to improve current standards. The major results are as follows: 1. Korean protective clothing is too thin and too heavy. Thicker, lighter, and more heat- resistant fabric and a lighter trim should be used. 2. Korean protective clothing is not very water-resistant. A Water-resistant outershell and an innerliner which are made of air permeable and water resistant fabric must be used. 3. Korean protective clothing's outershell and innerliner should be made of fabric that is more heat-resistant, flame-resistant, and chemical resistant. 4. Protective clothing should be more brightly colored and its reflective tape should have greater reflectivity to make firefighters more visible. 5. The fastner currently used in Korean protective clothing consists of Velcro, a button, and a D-ring which can not be opened and closed quickly. A better fastener would have just velcro and a zipper. 6. The uniform for Korean firefighters consists of only a protective coat and boots. Protective trousers should be added to the standard uniform. Also, a thermal harrier should be used in winter to protect firefighters from the cold. 7. Korean firefighters should be provided with their own personal sets of protective clothing to ensure a proper fit.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.15 no.3
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• pp.1-6
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• 2019

The basalt fiber, which is found to be non-toxic and harmless to the human body, is expected to become a trend for industrial fibers as they have better properties of non-combustion, heat-resistant, soundproof, absorbent, moistureproof, wear-resistant, corrosion resistant, lightweight, and high strength properties. Thus, in this study, we analyzed the chemical compositions of basalt produced at seven sites on Jeju Island for making a high value inorganic insulation material. The results showed that the MgO content of basalt collected from the eastern part of Jeju Island was higher than 7.5 percent, while that of the western region was less than 6 percent.

• Applied Chemistry for Engineering
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• v.20 no.4
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• pp.416-422
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• 2009

The buildings constructed with steel structure are coated with certified fire resistive material to resist from fire. All the building materials lose their initial performances as time passes by, so they need some maintenance. The Sprayed Fire Resistive Material (SFRM) also loses its performance and this performance loss of the SFRM is very important because fire resistance of buildings depends on SFRM. So this study was aimed to synthesis of alkali-silicates for SFRM and to evaluate the effect of alkali-silicates, K-silicates, Na-silicates and Li-silicates, by exchange of mole ratios as basic factors, tested solubility, intumescence ratios, thermal analysis, powder X-ray diffraction, fire-resistant and heat-resistant.

• Journal of Mechanical Science and Technology
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• v.17 no.10
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• pp.1475-1484
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• 2003

The EDM processing characteristics of one of the nickel-based heat resistant alloys, Hastelloy- X, were investigated under the various EDM conditions and analyzed in terms of surface integrity. This alloy is commonly used as a material for the hot gas path component of gas turbines and it is difficult to machine by conventional machining methods. The primary EDM parameter which was varied in this study were the pulse-on time. Since the pulse-on time is one of the main factors that determines the intensity of the electrical discharge energy, it was expected that the machining ratio and the surface integrity of the specimens would be proportionally dependent on the pulse-on duration. However, experimental results showed that MRR (material removal rate) and EWR (electrode wear rate) behaved nonlinearly with respect to the pulse duration, whereas the morphological and metallurgical features showed rather a constant trend of change by the pulse duration. In addition the heat treating process affected the recast layer and HAZ to be recrystallized but softening occurred in recast layer only. A metallurgical evaluation of the microstructure for the altered material zone was also conducted.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.154-157
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• 1996

The thin films are fabricated by VDPM and its heat resistant characteristics are investigated using Thermogravimetry. About polyimide, there is a wide difference between 5% weight loss temperature of TG curve and 20,000hr. of life time by methode of ASTM D2307. Therefore, TGI can be obtained by thermogravimetric analysis of NEMA std. pub. NOREI-1974. The TGI was got 670, 674 and 585 at 20$^{\circ}C$, 40$^{\circ}C$ and 70$^{\circ}C$, respectively.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.7
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• pp.1073-1080
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• 2000

Moisture transfer property of fabrics has known as one of the most important factors deciding wearer's subjective comfort not only thermally but also of sensorial. As a decisive property of fabric materials in determining human sensorial comfort, moisture vapor management property of heat resistant workwear material was examined in terms of increasing and decreasing rate and maximum value of relative humidity in the microclimate under the sweat pulse situation. An unique moisture regulation index, B$_{d}$, was calculated from the measurements using a novel dynamic sweating hot plate apparatus and was used to assess the buffering capacity of fabrics against a moisture vapor sweat pulse.e.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.210-211
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• 2006

This study presents the technology and application of hybrid insulation film for electric magnet wire. In order to make the high efficient motor with high space factor, it is necessary to develop a self-lubrication heat-resistant insulation film that can be used when the space factor 70% or more. A key to achieving high windability is to increase the lubricity and bonding strength of vanish, which for a magnet wire generally determines the mechanical scratches characteristics. Effective ways to reduce scratches include improving insulation film prepared by organic and inorganic hybrid synthesis methods.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.135-138
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• 1995

Recently, most of advanced materials used a wide industry field commonly have the characteristics of difficulty-to-cut materials. The cutting of difficulty-ro-cut materials have a variable optimum cutting conditions and methods according to materials. Above all,it is important of understanding to machinability of each materials. Especially, superalloy with Elevated Temperature Strength like as Incone1718 was used in nuclear power equipment and jet engine parts. This research shows a machining characteristics of Heat-Resistant alloy for high efficiency cutting through cutting force,tool wear and cutting temperature in SUS304 and Incone1718.

• Fire Science and Engineering
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• v.32 no.1
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• pp.46-56
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• 2018

The paper relates to a study on the conduction heat transfer characteristics according to the heating temperature of lightweight panel wall material. Plywoods, marbles, heat resistant glasses, as well as general gypsum board and fire-proof gypsum board, which have been widely used for lightweight panel wall material, were selected as experiment samples, and heating temperatures were set as $100^{\circ}C$, $200^{\circ}C$, $300^{\circ}C$, $400^{\circ}C$, $500^{\circ}C$ and $600^{\circ}C$. Next, each of the heating temperatures were introduced on the bottom part of the wall material for 30 minutes, and analyses were made on the heat transfer characteristics to the backside part on the top part through conduction. As results of the experiment, the maximum backside temperatures were measured up to $190^{\circ}C$ for a general gypsum board, $198^{\circ}C$ for a fire-proof gypsum board, $189^{\circ}C$ for a plywood, $321^{\circ}C$ for a marble, and $418^{\circ}C$ for a heat resistant glass as heating temperatures were introduced maximum of $600^{\circ}C$. In addition, the maximum change rate of conduction heat transfer were measured up to 85 W for a general gypsum board, 95 W for a fire-proof gypsum board, 67 W for a plywood, 1686 W for a marble, and 3196 W for a heat resistant glass as the maximum heating temperatures were introduced up to $600^{\circ}C$. Also, carbonization characteristics of the wallpapers were measured to visually check the danger of conduction heat transfer, and the results showed that smokes were first generated on the attached wallpapers for the heating temperature $600^{\circ}C$, which were 1021 s for a general gypsum board, 978 s for a fire-proof gypsum board, 1395 s for a plywood, 167 s for a marble, and 20 s for a heat resistant glass, and that the first generation of carbonization were 1115 s for a general gypsum board, 1089 s for a fire-proof gypsum board, 1489 s for a plywood, 192 s for a marble, and 36 s for a heat resistant glass.