• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.140.1-140
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• 2001

In order to survive in today's world of intense market competition, one of the major goals in the manufacture industry is to supply new products in an optimal time frame. To achieve this goal, there is an essential need to shorten delivery time through higher productivity, less trial and error in the designing process, and increase in efficiency in designing new products. For these purposes, AutoCAD is generally used; however, there are two basic limitations. First, AutoCAD requires individual designing for each product, and two, the program does not grant statistical results. The aim of this paper is to present both design and development of Automatic Specification Generation System(ASGS) for metal products. ASGS isan applied designing system that reproduces drawing ...

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2228-2231
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• 2007

Water gas shift reactor in fuel processing is an important part that converts carbon monoxide into hydrogen. Fuel processing system for PEMFC usually has two stages of WGS reactors, which are high temperature and low temperature shifter. In this study we prepared noble metal catalysts and compared their performances with that of a commercial iron chromium oxide catalyst. Noble metal catalysts and the commercial catalyst showed quite different temperature dependence of carbon monoxide conversion. The conversion of carbon monoxide at the commercial catalyst was very low at medium temperature(${\sim}300^{\circ}C$) and increased rapidly as temperature increased while the conversion at noble metal catalysts was high in the medium temperature range and decreased as temperature increased, which is thermodynamically expected. Their characteristics agreed well with the literature published, and we are accomplishing further study for improvement of the noble metal catalysts.

• Journal of Surface Science and Engineering
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• v.15 no.1
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• pp.24-38
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• 1982

The Objective of this study is to analyze structural and operational aspects of the govern-ment, its associations, industries and academic associations related to metal-plating industry, and thereby recommend ways of promotion of subsector, which is yet to be developed. Stages for the implementation are proposed as follows. 1) Stage One: Preparation for formation of proper atmosphere. ⅰ) Clearance of unlicenced metal-plating factories. ⅱ) Strengthening of functions of the association. ⅲ) Provision of incentives through the tax system. 2) Stage-Two : Modernization and maturity ⅰ) Introduction of system for indicating quality of products. ⅱ) Implementation of joint and cooperative-based programs ⅲ) Technical advancement of the closed system and anti-pollution treatment. 3) Stage Three : Settlement ⅰ) Systematic use of statistics and information. ⅱ) Standardization of quality of the products.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.216-227
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• 2007

Statement of problem: For the long-term success of removable partial dentures, the bonding between metal framework and denture base resin is one of the important factors. To improve bonding between those, macro-mechanical retentive form that is included metal framework design has been generally used. However it has been known that sealing at the interface between metal framework and denture base resin is very weak, because this method uses mechanical bonding. Purpose: Many studies has been made to find a simple method which induces chemical bond, now various bonding system is applied to clinic. In this experiment, shear bond strengths of heat-cured denture base resin to the surface-treated Co-Cr alloy were measured before and after thermocycling. Chemically treated groups with Alloy $Primer^{TM}$, Super-Bond $C&B^{TM}$, and tribochemically treated group with $Rocatec^{TM}$ system were compared to the beadtreated control group. The data were analyzed with two-way ANOVA. Result: 1. Shear bond strength of bead-treated group is highest, and Alloy $Primer^{TM}$ treated group, Super-Bond $C&B^{TM}$ treated group, RocatecTM system treated group were followed. Statistically significant differences were found in each treated group(p<0.05). 2. Surface treatment and thermocycling affected shear bond strength(p<0.05), however there was no interaction between two factors(p>0.05). 3. Shear bond strengths of bead-treated group and Alloy $Primer^{TM}$ treated group showed no statistically significant difference before and after thermocycling(p>0.05), and those of Super-Bond $C&B^{TM}$ treated group and $Rocatec^{TM}$ system treated group showed statistically significant difference after thermocycling(p<0.05).

• Journal of Powder Materials
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• v.9 no.5
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• pp.346-351
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• 2002

Pure and fine, two-component titanate powders (barium titanate, calcium titanate etc.) were synthesized by an ethylene glycol method. Titanium isopropoxide and other metal ionic salts were dissolved in liquid-type ethylene glycol without any precipitation. In non-aqueous system, the amount of ethylene glycol affected the solubility and homogeneity of metal cation sources in the solution. At the optimum amount of the polymer, the metal ions were dispersed effectively in solution and a homogeneous polymeric network was formed. Most of the synthesized powders had sub-micron or nano-size primary particles after calcination and the agglomerated calcined powders were easily ground by ball milling process. All synthesized titanate powders had stable crystallization behavior at low temperature and high specific surface area after ball milling. The crystallization behavior and the microstructures of the calcined powders were affected on the ethylene glycol content.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.438-439
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• 2011

Magnetic levitation control system of a metal ball was designed using combined PID and fuzzy logic, in which two electromagnets are used to control the vertical and horizontal position of the ball. Single synchronization coil sensor was used to detect the vertical position. Electric power is differentially supplied to two electromagnets so that the ball can move horizontally. In the experiment 25 cm diameter metal ball was levitated and successfully controlled to move horizontally.

• Journal of Pharmaceutical Investigation
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• v.39 no.2
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• pp.85-91
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• 2009

Microcrystallized cellulose xanthate-metal-oxytetracycline complexes (MCX-metal-OTC) were prepared and evaluated as a controlled release system for the antibiotics. Microcrystallized cellulose (MC) was chemically modified to xanthated microcrystallized cellulose (MCX). One-bath method, where MCX was reacted with OTC-metal complexes, afforded greater amount of OTC bound to the polymeric matrix than did two-bath method, where MCX-metal complexes were treated with OTC. The OTC release from MCX-metal-OTC was greatly sustained compared with that from a mixture of MC/metal/OTC. Furthermore, MCX-metal-OTC manifested antibacterial activity, which lasted for 11-18 days. These results suggest that MCX-metal-OTC is a polymeric antibiotics with prolonged antibacterial activity.

• International Journal of Air-Conditioning and Refrigeration
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• v.14 no.3
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• pp.94-101
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• 2006

A theoretical investigation to find thermodynamically optimum design conditions of conduction-cooled Peltier current leads is performed. A Peltier current lead (PCL) is composed of a thermoelectric element (TE), a metallic lead and a high temperature superconductor (HTS) lead in the order of decreasing temperature. Mathematical expressions for the minimum heat flow per unit current crossing the TE-metal interface and the minimum heat flow per unit current from the metal lead to the joint of the metal and the HTS leads are obtained. It is shown that the temperature at the TE -metal interface possesses a unique optimal value that minimizes the heat flow to the joint and that this optimal value depends on the material properties of the TE and the metallic lead but not the joint temperature nor electric current. It is also shown that there exists a unique optimal value for the joint temperature between the metal and the HTS leads that minimizes the sum of the power dissipated by ohmic heating in the current leads and the refrigerator power consumed to cool the lead, for a given length of the HTS.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.523-524
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• 2007

This paper discusses the planarization process of thick copper film structure used for power supply device. Chemical mechanical polishing(CMP) has been used to remove a metal film and obtain a surface planarization which is essential for the semiconductor devices. For the thick metal removal, however, the long process time and other problems such as dishing, delamination and metal layer peeling are being issued, Compared to the traditional CMP process, Electro-chemical mechanical planarization(ECMP) is suggested to solve these problems. The two-step process composed of the ECMP and the conventional CMP is used for this experiment. The first step is the removal of several tens ${\mu}m$ of bulk copper on patterned wafer with ECMP process. The second step is the removal of residual copper layer aimed at a surface planarization. For more objective comparison, the traditional CMP was also performed. As an experimental result, total process time and process defects are extremely reduced by the two-step process.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.2
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• pp.103-111
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• 2002

Out of all metal-cutting process, the hole-making process is the most widely used. It is estimated to be more than 30% of the total metal-cutting process. It is therefore desirable to monitor and detect drill wear during the hole-drilling process. One important aspect in controlling the drilling process is monitoring drill wear status. There are two systems, Basic system and Online system, to detect the drill wear. Basic system comprised of spindle rotational speed, feed rates, thrust torque and flank wear measured by tool microscope. Outline system comprised of spindle rotational speed feed rates, AE signal, flank wear area measured by computer vision, On-line monitoring system does not need to stop the process to inspect drill wear. Backpropagation neural networks (BPNs) were used for on-line detection of drill wear. The output was the drill wear state which was either usable or failure. This paper deals with an on-line drill wear monitoring system to fit the detection of the abnormal tool state.