• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.269-274
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• 1999

Aluminum alloy has not only physical characteristic of very high activated high thermal conductivity and high thermal coefficient expansion but also special characteristic of great difference fusibility of hydrogen between liquid and solid phase. Because of these reasons, Aluminum welding is very different. Therefore, only MIG welding method should be applied instead of other welding methods. In this study, in order to select optimal welding conditions, it has been to investigate the effectiveness on the welding current, welding speed, flow rate of gas and welding voltage to occurrence of spatters, external shape of bead, state of penetration and width and hight of bead by using filer metal of A15356(dia. 1.21mm) on the base material of A16061.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.11-19
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• 2011

A localization development of Composite rotor blade for Smart Unmanned Aerial Vehicle(SUAV) has been conducted. Overall localization development encompassed selection of domestic composite material having similar properties to that of original one at its best, coupon tests for data base of new material properties, re-calculation of blade sectional properties, and validation of structural/dynamic design requirements such as isolation of rotor natural frequency from excitation, static and fatigue strength, aeroelastic stability. The results of all these activities are described. This paper briefly discusses the improved manufacturing process for the localization of SUAV blade.

• Journal of the Korean Society of Safety
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• v.18 no.4
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• pp.148-154
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• 2003

There are now the plating process that have many hazardous factor cause of the using numerous noxious chemical and bad working environments. The purpose of the study is to make a selection of suitable safety evaluation method that can analyze and righteously find with numerous hazardous factor of the plating process. And another purpose is to systematically adjust the risk of plating process by comprehension of the role of process, equipment, and source material. Therefore, these studies are carried out in the following three investigations of this report. The first research understands the injurious human health and environment by analyzing hazardous material based on the MSDS. To evaluate the safety of process and compartment, the second research is proposed the security secure counterproposal by using the FMEA and the HAZOP. The final research is devoted to systematically analyze the hazard by applying for reasonable guide word and doing the HAZOP for hazardous factor in specific process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.85-88
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• 2000

FRP has been used very much as high strength core materials for insulators because of its high strength and good insulation properties. In this study cantilever, tension and torsion stress were simulation along to the unidirection glass fiber. In addition, FRP was made by pultrusion method. This paper proposed the procedure of the finite element model updating and pretest using the commercial finite element code MSC. Nastran. To enhance the efficiency of experimental modal analysis, we proposed the process which is the selection of the locations and the number of measurement points for pre-test.

• Proceedings of the KAIS Fall Conference
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• 2004.06a
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• pp.335-338
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• 2004

Life-Cycle Engineering(LCE) is a decision-making methodology that considers environmental and cost needs during the product life-cycle. Environmental conscious design and manufacturing has become more and more important and it has been enforced by governmental regulations and used as trade restriction. LCE involves integrating environmental consideration into new product development including design, material selection, manufacturing processes and distribution of the product to the consumers, plus the end-of-life management such as disassembly, material recovery, remanufacturing of the product after discarding it. In this paper, a state-of-the-art survey of LCE is presented.

• Journal of the Korean Solar Energy Society
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• v.28 no.5
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• pp.8-13
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• 2008

In this study, we analyze the electrical optical characteristics of transparent glass for photovoltaic and glass-glass module application. The elemental facts from raw glass to laminated glass with solar cells are analyzed using UV spectrophotometer and spectroradiometer. From the data of transmittance and reflectance, the optimum PV module processing condition and selection of material for fabrication should be considered deeply for obtaining high module efficiency. Also we introduce two glasses which has 2%$\sim$4% higher transmittance using coating technology with anti-reflection material. From this experiment, we try to give some basic information for PV module manufacturing industry. The detail description is specified as the following paper.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.8
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• pp.652-660
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• 2003

T-history method, measuring heat-of-fusion of phase change material (PCM) in sealed tubes, has the advantages of a simple experimental device and no requirements in sampling process. However, a degree of supercooling used in selecting the range of latent heat release and neglecting sensible heat during the phase change process can cause significant errors in determining the heat of fusion in the original method, which has been improved in order to predict better results by us. In the present study, the modified method was applied to a variety of PCM such as paraffin and lauric acid having very small or no supercooling with a satisfactory precision. Also the selection of inflection point and temperature measurement position was fumed out not to affect the accuracy of heat-of-fusion significantly. As a result, the method can provide an appropriate means to assess a new developed PCM by cycle test even if a very accurate value cannot be obtained.

• Applied Microscopy
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• v.48 no.4
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• pp.122-125
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• 2018

The focused ion beam (FIB) method is widely used to prepare specimens for observation by transmission electron microscopy (TEM), which offers a wide variety of imaging and analytical techniques. TEM has played a significant role in material investigation. However, the FIB method induces amorphization due to bombardment with the high-energy gallium ($Ga^+$) ion beam. To solve this problem, electron beam induced deposition (EBID) is used to form a protective layer to prevent damage to the specimen surface. In this study, we introduce an optimized TEM specimen preparation procedure by comparing the EBID of carbon and tungsten as protective layers in FIB. The selection of appropriate EBID conditions for preparing specimens for TEM analysis is described in detail.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.4
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• pp.329-339
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• 2015

Purpose: To investigate the information acquisition, selection criteria and selection methods of Mongolian dentists regarding adhesive agents for bonded restorations, and to provide future direction for continuing education. Materials and Methods: One hundred Mongolian dentists were interviewed and asked to complete a questionnaire containing 7 questions on general information about the responder, 8 questions on information acquisition and selection of bonded restoration agents, and 10 questions on continuing education. Results: Objective and credible information regarding bonded restoration materials were not being acquired, and logical material selection was not being made. The extent of continuing education was inadequate and not enough information regarding education was being acquired. The participants responded positively to online supplementary education. Conclusion: A systemized approach needs to be established in Mongolian dentistry to enable organized delivery of evidence-based guidelines and information, and logical selection of the numerous and various bonded restoration agents. Furthermore, the education of dentists, through various means, is required to enable proper use of the selected materials.

• Journal of the Korea Concrete Institute
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• v.24 no.1
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• pp.45-52
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• 2012

A variety of retrofit material such as CFRP, GFRP, and PolyUrea have been developed for strengthening RC structures and infrastructures. From previously reported research results, the capacity of strengthened concrete structures was dictated by the behavior of the interface between retrofit material and concrete. In this study, bond-shear test was carried out to estimate the bond behavior between retrofit material and concrete using a newly developed test grip. The test results of load and slip relation and energy absorption capacity of each retrofit material were obtained. These test results will provide basic information for retrofit material selection to achieve target retrofit performance.