• KSBB Journal
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• v.8 no.2
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• pp.126-132
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• 1993

The objective of this study was to develop an artificial dentin for easy handle and accurate observation of the mechanism on dental caries and to screen biologically active materials from the extracts of traditional plants and fruits for prevention of early dental cares. In order to produce disc PAHA (artificial dentin), the powdered hydroxylapatite was immobilized in a 20% polyacrylamide gel. The characteristics of disc PAHA was very similar to the surface, figure and lattice of human enamel. After decalcification in 0.1M citric acid based on observation with SEM. The critical point of decalcification of disc PAHA by acids was found to be pH 5.0-5.5, which was hi agreement with human enamel. The degree of decalcification from disc PAHA in 0.1M citric acid solution was sixfold higher than that of human enamel. This result suggested that disc PAHA would be useful as a substitute of human enamel for in vitro experiment. The extracts of garlic and Flower Apple A, B seemed to inhibit growth of S. mutans. Especially, when the 300$\mu\ell$ of its extracts added to the medium to incubate S. mutans, F. apple B showed strongly an inhibitory effect in both the growth of S. mutans and the synthesis of insoluble glucan.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.35-36
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• 2023

Safety management of steel frame members is a very important part to maintain safety and function. However, precise inspection is not possible for steel frame members due to finishing materials and insulation materials, leading to poor inspection. For steel members, an insulating spray coating method is used for high thermal conductivity. The insulation spray method is not only uneconomical, but also has the disadvantage of spoiling the aesthetics. In addition, VOCs are released from paints used in spraying, so a solution is needed. In this study, heating paint was used to improve the disadvantages of the insulation spray coating method and the high thermal conductivity of steel frame members. In addition to this, in order to reduce VOCs generated from the paint, active clay was added to produce a functional exothermic paint, and then the experiment was conducted. As the amount of activated clay increased, the film thickness increased, and the VOCs emission and thermal conductivity decreased.

• International journal of advanced smart convergence
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• v.2 no.2
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• pp.16-18
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• 2013

In this paper, we develop a method to design a flexible thin film audio systems utilizing Polyvinylidene fluoride. The system we designed showed the properties of increased transparency and sound pressure levels. As an input terminal transparent oxide thin film is adopted. In order to provide dielectric insulation, a transparent insulating oxide thin film is coated to obtain double -layered structure. In the range of visible light, the output from the output of the system showed an increased and improved sound pressure level. The piezoelectric polymer film of polyvinylidene fluoride (PVDF) is used to produce mechanical vibration due to the applied electrical voltage signal. An analog electric voltage signal is transformed into sound waves in the audio system.

• International Journal of Internet, Broadcasting and Communication
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• v.6 no.1
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• pp.13-15
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• 2014

We develop a method to fabricate a flexible thin film audio systems using polyvinylidene fluoride(PVDF). The system we designed showed the properties of increased flexibility, transparency, and sound pressure levels. As an input port of two terminals, transparent oxide thin film with a low resistivity is adopted. In order to provide dielectric insulation, a transparent insulating oxide thin film is coated to obtain double-layered structure. In the range of visible light, the output from the output of the system showed a increased and improved sound pressure level. The piezoelectric polymer film of PVDF is used to produce mechanical vibration due to the applied electrical voltage signal. An analog electric voltage signal is transformed into sound waves in the audio system.

• IE interfaces
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• v.12 no.1
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• pp.102-113
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• 1999

BOM(Bill of Material) is a description of parts, assemblies and raw materials that comprise a product structure. In manufacturing companies that produce various products with short life cycles, it is very important to manage to BOM of products with various options and versions efficiently. This paper describes an effective modeling and implementing technique of Generic BOM Management System(GBMS) for management of number of variant products. In this paper, OMT(Object Modeling Technique) was used to model a generic BOM and Object-Relational Database Management System(ORDBMS) was used to implement the GBMS database. In order to prove the effectiveness of proposed methodology, a case that assembles computer with various options was studied.

• Elastomers and Composites
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• v.54 no.1
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• pp.70-76
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• 2019

The function and purpose of the marine rubber fender, to prevent the damage of the ship and the mooring while the ship is being attached to the pier. However, maintenance of the fender after installation is not enough, because it is generally handled as an attachment facility. Estimation the life of a marine rubber fender is important in the maintenance of a port. When manufacturers design and produce marine rubber fenders, they do so according to various conditions such as the reaction force acting on the hull and docking vessel and deformation after absorbing the kinetic energy of the ship. In this study, a method for predicting and evaluating service life from the product design and development stage was established, in order to evaluate the durability of the marine rubber fenders. The SSp-300H and HSP-300H models were used to predict the service life. The method developed in this study, is expected to predict the service life of the marine rubber fender accurately and in a comparatively shorter time, thereby contributing to the evaluation standard and quality stability of the product.

• Transactions of Materials Processing
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• v.9 no.3
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• pp.242-248
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• 2000

This paper is concerned with the family of parts that generally feature a central hub with radial protrusions. Radial Extrusion is usually used in order to produce complex parts, which is combined with upsetting and/or forward and backward extrusion. Typical parts that fall into this category include cross pieces for universal joints, key-shaft type parts, tube fittings, and differential gears. In this paper, the forming characteristics of radial extrusion combined with forward extrusion is investigated by comparing the punch and mandrel loads. The design factors during radial extrusion combined with forward extrusion are applied to the simulation to see how much those factors have effect on the forming loads. The rigid-plastic FEM is applied to the simulation.

• Transactions of Materials Processing
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• v.13 no.3
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• pp.190-204
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• 2004

The objective of this study is to develop a highly accurate micro tool alignment system applicable to the micro machining technology. In a specific application such as micro hole punching, radial clearance between micro tools is order of a few micron. Under this micron scale tool clearance, accuracy of tool alignment is very important for ensuring hole quality. In the present study, a two-way image acquisition system was developed, which can produce overlapped image of both micro tools that face each other, and applied to the tool alignment in the micro punching. Also, to meet alignment accuracy of tools within $1\mu\textrm{m}$, the cross correlation image processing algorithm was employed. With this system, $25\mu\textrm{m}$ punching tools with $1\mu\textrm{m}$ radial clearance could be accurately aligned.

• Transactions of Materials Processing
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• v.27 no.4
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• pp.244-249
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• 2018

Rhodium is a representative platinum group material. Rhodium is used in several industrial fields including jewelry, chemical reaction catalyst, electric component etc. In recently, ultra-fine rhodium wire has been applied to the pins of probe card used to test a semiconductor. In this study, in order to produce a fine rhodium wire with the diameter of $50{\mu}m$, a fine rhodium wire drawing process was designed. After design of the fine wire drawing process by using a uniform reduction ratio theory, finite element analysis was performed. Finally, fine wire drawing experiment was performed to verify the effectiveness of the designed process.

• International Journal of Concrete Structures and Materials
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• v.7 no.2
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• pp.111-117
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• 2013

Heavy oil fly ash (HOFA) is a byproduct generated by the burning of heavy fuel oil. Chemical analysis showed that HOFA is mainly composed of unburned carbon with a significant amount of heavy metals. Due to toxicity, management of this waste poses a challenge to the industry personal. The present study investigates the possible use of HOFA as a black pigment or admixture in cement mortar aiming to produce ornamental brick. In order to investigate the change of cement mortar strength when HOFA is added, the standard compressive strength test with 50 mm cubes was performed. The results showed that the addition of 2-5 % of HOFA in cement mortar does not affect its strength. The leaching behavior of trace elements within HOFA and HOFA mixed mortar were investigated through laboratory batch leaching experiments. The results confirmed that HOFA can be utilized as a black pigment in ornamental brick, which is environmentally safe and provides good balance between color and brick properties.