• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.160-162
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• 2004

The aim of this study is to make the technical standards for certificating a high efficiency metal-halide lamps and reflectors using the high intensity discharge lamps, to accomplish the practical energy saving effect. Metal-halide lamps are certificated by stabilzed and restarting time, lamp voltage, current, power and light output efficiency. The high illumination reflectors using HID lamps are certificated by testing reflective index, fading, the melting point, glare and install spacing factor.

• Korean Journal of Materials Research
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• v.15 no.1
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• pp.37-41
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• 2005

Stainless steel fibers with a diameter of $17\;{\mu}m$ and 630 nm were produced from stainless steel wires by the drawing/annealing/exfolitation process. The suitable sheath material to draw the core stainless steel wires to fibers was the Cu coating. The low melting metal of Zn was not a suitable sheath coating. Also, an attempt was made to produce $20\;{\mu}m{\Phi}Ti$ fibers from the core titanium wires. The main obstacles in producing Ti fibers were their resistance to deformation owing to the Ti's hop structure, and high reactivity of Ti with the exfolitation solution.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.156-159
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• 2006

Gasification and melting method is one of the most potential means for waste treatment process with low emission of fly ash or heavy metal, dioxin and high possibility of using slags as resources. Moisture contents influences directly a gasification characteristics of waste. So it is necessary to investigate the effect of moisture contents in gasification. But it is hard to consider the effect of moisture contents, using samples of powder form of Milligram's order in existing thermogravimetric analyser. Therefore, we made a thermogravimetric analysis device to applicate samples of Gram's order. Gasification characteristics are typically reported with result from thermogravimetric analysis date for wood and RDF samples along with changing moisture contents. It is discussed the way to apply these analysis results to gasification and melting furnace.

• Journal of Welding and Joining
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• v.13 no.4
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• pp.147-154
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• 1995

In order to study the bonding mechanism of Ni/B/Ni transient liquid phase bonding system, width of liquid layers were calculated, where in this system melting point of insert material(B) is higher than bonding temperature and melting point of base metal(Ni). Caclulated values were compared with experimental ones which were measured by bonding Ni/B/Ni system at 1433-1474K under vacuum atmosphere. As results, the width of initial liquid layer of Ni/B/Ni system was calculated as $W_{IL}$ = $W_{o}$[1 + {2.100..rho.$_{S/}$ ( $X_{3}$ + $X_{4}$)..rho.$_{Ni}$ }-.rho.$_{S/}$.rho. Ni/], and it was nearly same with experimental values. Maximum width of liquid layer, width of liquid layer during isothermal solidification and isothermal solidification time were calculated also.o.o.o.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.355-357
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• 2011

Several researches and patents has been published on gathering impurity from both upper and lower places of melting zinc bath and collecting them using melting resolution, but they have never discovered work model applied in the field. This paper proposes an effective extraction algorithm for hazardous work robot that is designed to detect impurity in steel manufacturing process.

• Journal of Welding and Joining
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• v.27 no.1
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• pp.59-64
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• 2009

In order to determine the One-Drop One-Pulse(ODOP) condition of the pulsed gas metal arc(GMA) welding, the drop detaching phenomenon during the peak time is investigated using the force-displacement model. The drop detaching criterion is established based on the displacement of the pendant drop, and the forces exerted on the drop are calculated using the Modified Force Balance Model(MFBM). The effects of wire melting on the drop size and force are included in the force-displacement model. While the peak current has most significant effects on the drop detaching time, the initial drop mass prior to the peak time also influences drop transfer. The calculated results show good agreements with the experimental data, which implies that the ODOP condition can be predicted using the force-displacement method.

• Journal of the Korean Ceramic Society
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• v.32 no.10
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• pp.1093-1102
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• 1995

Water-soluble phosphate glasses containing Ag or Cu ion were prepared through melting process. Then the powdered glass samples were dissolved in D.I. water at room temperature with changing the dissolution time. In terms with the glass composition, dissolution characteristics, bactericidal effects and cytotoxicities were investigated. Dissolved amounts increased uniformly with dissolution time, and the dissolution rate was higher for ternary glass than for binary glass and with less metal oxide amount. And the dissolution rate of the glass with Ag ion was higher than that with Cu ion, and the bactericidal effect of the glass with Ag ion was also greater. Solution with more than 25 ppm of Ag was observed to have strong cytotoxicity to L929, and solutions of lower Ag concentration or with Cu seemed to have little cytotoxicity.

• Transactions of Materials Processing
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• v.20 no.8
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• pp.575-580
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• 2011

Direct laser melting(DLM) is promising as a joining method for producing parts for automobiles, aerospace, marine and medical applications. An advantageous characteristic of DLM is that it affects the parent metal very little. The mechanical properties of parts made by DLM are strongly affected by the porosity and surface roughness of the laser melted beads. This is a systematic study of the effects of the porosity and surface roughness of laser melted beads using various processing parameters, such as laser power, scan rate and overlapping ratio of the fill spacing. The specimens were fabricated with 316L and 304L austenitic stainless steel powder. Dense parts with low porosity were obtained at low laser scan speed, as it increased the aspect ratio of the parental material and the depth of penetration. The variations of surface roughness were examined at various processing parameters such as overlapping ratio and laser power.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.3
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• pp.284-292
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• 2020

In this study, hydrogen charging was conducted for API X70 steel by the electro-chemical hydrogen charging method. Right after hydrogen was diffused from the specimen surface to the inside of the X70, the small punch tests and hydrogen concentration analysis was conducted within 5 minutes. Hydrogen was analyzed by melting the whole specimen and detect the gas after melting. Mechanical properties were measured by the small punch (SP) testing. Fracture surface and specimen surface were observed using scanning electron microscope. Three tests were repeated for study sensitivity of the SP test results under a same charging condition. It was observed that the variation of the maximum load, SP displacement at failure, hydrogen concentration as the charging period was not much in the case of X70 as the other steel such as Inconel. It can be argued that X70 base metal may have high hydrogen damage resistance and hydrogen diffusion in the base metal would not cause much embrittlement. Limitations of the SP test with 0.5 mm thickness for hydrogen damage test for X70 were discussed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.4
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• pp.322-328
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• 2000

Welding means that metal parts are joined by melting (with or without a filler material) or that new material is added to a metal part by melting. Welding of metal parts is an important technology method in manufacturing processes of capstan drum for costal vessels. Thermal stresses due to the non-uniform temperature fields during welding influence both the fabrication and the use of the weldment. In the problem of this thermal effect, particularly it is a well known that analysis for temperature gradient, temperature distribution, and the like become consequence factors to a safety and a strength design. This paper analyzes the temperature distribution of welding part in capstan drum for the inshore and costal vessels using finite element method. At early stage of the cooling after welding processes, the abrupt temperature gradient has been shown in vicinity of the bottom face of welding part. Therefore it calculates the numerical value that can be applied to the optimal design of welding parts in the shapes for capstan drum.