• Korean Journal of Materials Research
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• v.21 no.5
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• pp.255-262
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• 2011

This paper has relatively high technical standard and experimental skill. The fabrication of TCO film with high transparency, low resistance and low chromaticity require exact control of several competing factors. This paper has resolved these problems reasonably well, thus recommended for publication. Indium tin oxide(ITO) thin films were by D.C. magnetron roll-to-roll sputter system utilizing ITO and $SiO_2$ targets of ITO and $SiO_2$. In this experiment, the effect of D.C. power, winding speed, and oxygen flow rate on electrical and optical properties of ITO thin films were investigated from the view point of sheet resistance, transmittance, and chromaticity($b^*$). The deposition of $SiO_2$ was performed with RF power of 400W, Ar gas of 50 sccm and the deposition of ITO, DC power of 600W, Ar gas of 50 sccm, $O^2$ gas of 0.2 sccm, and winding speed of 0.56m/min. High quality ITO thin films without $SiO_2$ layer had chromaticity of 2.87, sheet resistivity of 400 ohm/square, and transmittance of 88% and $SiO_2$-doped ITO Thin film with chromaticity of 2.01, sheet resistivity of 709 ohm/square, and transmittance of more than 90% were obtained. As a result, $SiO_2$ was coated on PET before deposition of ITO, their chromaticity($b^*$) and transmittance were better than previous results of ITO films. These results show that coating of $SiO_2$ induced arising chromaticity($b^*$) and transmittance. If the thickness of $SiO_2$ is controlled, sheet resistance value of ITO film will be expected to be better for touch screen. A four point probe and spectrophotometer are used to investigate the properties of ITO thin films.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.1
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• pp.23-27
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• 2016

This study investigates the effect of carbon fiber sheet (CFS) and carbon fiber strand sheet (CFSS) on the fatigue resistance and compressive strength of RC slabs. The results of a comparison of the number of equivalent cycles between the CFS- and CFSS-reinforced RC slab test specimens obtained from a fatigue test indicate that the CFSS-reinforced RC slab has 1.2~1.3 times greater effect of reinforcement than the CFS-reinforced RC slab. This study also indicates that the fatigue resistance of the CFS- and CFSS-reinforced RC slabs is ensured when the compressive strength of concrete is not lower than the specified design strength prescribed in the Specifications for Highway Bridges but is not ensured when the compressive strength of concrete is lower than the specified design strength, although the effect of reinforcement is secured.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.131-135
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• 2003

The form-joining process (or clinching) uses a set of die and punch to impose the plastic deformation-induced geometric constraint on a sheet metal pair, But their joining strength ranges 50-70 percent of that of the resistance spot welding. In this paper, a new form-joining process with the aid of adhesive is proposed in which an epoxy adhesive is applied to a sheet metal pair, to improve joining strength. The strength and mechanical properties of the new process are discussed and compared for other joining processes.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.1-4
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• 2005

This study is to examine adhesion the characteristics of self adhesive asphalt to minimize of the construction periods and the environmental problems through the performance estimation of materials to reduce waterproof problem and the long durability maintenance of building structures. This study tested the estimation items of self rubberized adhesive asphalt to examine the sheet discovered the most important problem in the construction site and the connection stability in the sheet joint. Besides, this study examined the material characteristics such as tension property, tear property, temperature dependence, heat resistance, adhesion stability and so on. Test results of the separative items satisfied in the reference figure of connection stability and adhesion stability which could confirm adhesion performances and other items also satisfied in the reference.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.4
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• pp.121-128
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• 2001

This study has been performed to investigate formability of non-vinyl PCM(pre-coated metal)sheet. First, physical test of PCM sheets were tested to evaluate finish coating characteristic of PCM. And then, test equipment was made for friction test and three non-vinyl PCM sheets were tested by straight pulling method. This paper provides the results of the friction tests showing the influence of sheet surface texture and process conditions. It was found that the influence of contact pressure and speed had an effect upon the level of friction. Also using tests, the scratch resistance of a series of polyester coating has been investigated. This investigation aims to clarify the process conditions that prevent the scratch of PCM to form the good electrical appliances such as microwave oven, air conditioner and refrigerator etc.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.42-45
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• 2003

The purpose of this study is the development or the extensive Rapid Prototyping Technique. which can resolve the long-term manufacturing process, shrinkage and deformation occurring rapid prototyping technique. To begin with. the various specimens for tensile were manufactured on the basis of this modeling technology. Then, many kinds of the laminate pieces for the test were made by using the sheet metals lmm and 1.5mm thickness which is composed of the same ingredient. The tensile specimen were manufactured by changing the process variables, Such as electric current, pressure and resistance welding time for the Rapid Prototyping with metal sheet. And then by using the Taguchi method. The interrelation between the specimen and mechanical properties were determined and the system for the optimum process variable organized.

• Laser Solutions
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• v.10 no.4
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• pp.7-12
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• 2007

The aluminized steel sheet exhibits excellent resistance to oxidation and corrosion, and can substitute for stainless steel or heat-resisting steel in some situations. Furthermore it has wide applications, owing to its low cost and excellent performance, in the petrochemical industry, electric power, other energy conversion system, etc. and has attracted the attention of many investigators. Laser welding is a remarkably advantageous method for welding of thin sheets and surface-treated steel sheets since the method requires less heat input, and it is suitable for high-speed welding. In this study, thus, the laser weldability of aluminized steel sheet was investigated. As the result from the study, there is an Al-rich zone in a welded part which has decreased the welding strength due to the intermetallic compounds in the Al-rich zone.

• Transactions of Materials Processing
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• v.14 no.3 s.75
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• pp.277-281
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• 2005

LTCC(Low temperature co-fired ceramic) is being recognized as a significant packaging material of electrical devices for the advantages such as relatively low temperature being needed for process, low conductor resistance and high printing resolution. In the process of LTCC electrical devices, the punched via-hole quality is one of the most important factors on the performance of the device. However, its mechanism is very complicated and optimization of the process seems difficult. In this paper, to clarify the process, via-hole punching experiments were carried out and the punched holes were examined in terms of their burr formation. The effects of thickness of PET sheet, ceramic sheet and punch-to- die clearance on via-hole quality were also discussed. Optimum process conditions are proposed and a factor $\kappa$ is introduced to express effect of the process variables.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.526-531
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• 1996

Most of existing tunnels in Korea have structural and material defects, such as lack of the thickness in the crown and presence of an opening behind thie lining as a result of its construction. In Japan, it is said that carbon fiver sheet is very attractive for the upgrading damaged tunnel due to its good tensile strength, handability and resistance to corrosion. This report is the summary of the applicability of continous carbon fiber sheet for a repair and reiforcement of existing tummel located in Masan. It is the aim of this study to analyze the site data related to consturcion method used carbon fiber sheet.

• Journal of the Korean Geotechnical Society
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• v.20 no.1
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• pp.13-19
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• 2004

The major distress types in the domestic asphalt pavement are fatigue cracking, reflection cracking, thermal cracking, and rutting. To decrease the pavement distress by reinforcing asphalt pavement with reinforcement interlayer in geosynthetics to the traditional pavement systems can improve these problems. This study conducted laboratory test with asphalt pavement reinforced by glass fiber sheet to fix systematically geosynthetic asphalt pavement system. Laboratory tests like wheel tracking test and crack resistance test are conducted to analyze the controlling effect of glass fiber sheet on cracking and rutting of asphalt pavement.