• Advances in materials Research
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• 제5권2호
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• pp.121-130
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• 2016

In an attempt to reach a balance of performances in homo-polypropylene based system, the effects of single and hybrid reinforcements inclusions comprising calcium carbonate nanoparticles (2, 4 and 6 phc) and glass fibers (10 wt.%) on the mechanical and thermal properties were investigated. Different samples were prepared by employing twin-screw extruder and injection molding machine. In morphological studies, the uniform distribution of glass fibers in PP matrix, relative adhesion between glass fibers and polymer, and existence of nanoparticles in polymer matrix were observed. $PP/CaCO_3$ (6 phc) as compared to pure PP and PP/GF had superior tensile and flexural strengths, impact resistance and deformation temperature under load (DTUL). $PP/GF/CaCO_3$ (6 phc) composite displayed comparable tensile and flexural strengths and impact resistance to neat PP, while its tensile and flexural moduli and deformation temperature under load (DTUL) were 436%, 99% and $26^{\circ}C$greater respectively. The maximum impact resistance was observed in $PP/CaCO_3$(6 phc). The highest DTUL was perceived in PP hybrid nanocomposite containing 10 wt.% glass fiber and 4 phc $CaCO_3$ nanoparticle.

• 한국분말재료학회지
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• 제8권1호
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• pp.49-54
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• 2001

The synthesis and characteristics of W-Ni-Fe nanocomposite powder by hydrogen reduction of ball milled W-Ni-Fe oxide mixture were investigated. The ball milled oxide mixture was prepared by high energy attrition milling of W blue powder, NiO and $Fe_2O_3$ for 1 h. The structure of the oxide mixture was characteristic of nano porous agglomerate composite powder consisting of nanoscale particles and pores which act as effective removal path of water vapor during hydrogen reduction process. The reduction experiment showed that the reduction reaction starts from NiO, followed by $Fe_2O_3$ and finally W oxide. It was also found that during the reduction process rapid alloying of Ni-Fe yielded the formation of $\gamma$-Ni-Fe. After reduction at 80$0^{\circ}C$ for 1 h, the nano-composite powder of W-4.57Ni-2.34Fe comprising W and $\gamma$-Ni-Fe phases was produced, of which grain size was35nm for W and 87 nm for $\gamma$-Ni-Fe, respectively. Sinterability of the W heavy alloy nanopowder showing full density and sound microstructure under the condition of 147$0^{\circ}C$/20 min is thought to be suitable for raw material for powder injection molding of tungsten heavy alloy.

• Design & Manufacturing
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• 제11권3호
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• pp.35-40
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• 2017

PCR(Polymerase chain reaction) is a technique to replicate and amplify a desired part of DNA. It is used in various aspects such as DNA fingerprint analysis and rare DNA amplification of an extinct animal. Especially in the medical diagnosis field, it provides various measurement methods at the molecular level such as genetic diagnosis, and is a basic tool for molecular diagnostics. The internal shape of the plastic vial tube for PCR analysis used in the DNA detection process, and the surface roughness and internal cleanliness can affect detection and discrimination results. The plastic vial tube demanded by the developer of the PCR analysis equipment should be changed to a structure that eliminates the residual washing solution in the washing process to ensure the internal cleanliness. Thus the internal structure and the internal surface design for improving the PCR amplification efficiency are key issues to develop the plastic vial tube for the DNA detection process.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.331-332
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• 2007

In this work, the TiO2 pigment influence in HDPE dielectric strength was analyzed. Chemical and structural characterizations were made to identify changes during the processing and your influence in the electrical properties, formulations containing 0, 0.5, 1, 2.5, 4 and 6 of titanium dioxide were processed by extrusion and injection molding with stabilization-antioxidants, ultraviolet stabilizers and plasticizers. The electrical strength tests were analyzed by the statistical distribution of Weibull, and the maximum likelihood method. The high concentrations present lower values to electrical strength. The parameter could be using to insulator panicles dispersion. The TiO2 concentration variation shows that these incorporations implicate strength values increase has a maximum (5,35MV/cm). High pigment concentration induces a little falls in property values. Observing the parameter, minimum experiment electric field (Ebmin) and electric strength value, found that the best electric perform formulation was the formulation with 2.5% TiO2 weight.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1982-1983
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• 2007

In this work, the $TiO_2$ pigment influence in HDPE dielectric strength was analyzed. Chemical and structural characterizations were made to identify changes during the processing and your influence in the electrical properties. Formulations containing 0, 0.5, 1, 2.5, 4 and 6 of titanium dioxide were processed by extrusion and injection molding with stabilization-antioxidants, ultraviolet stabilizers and plasticizers. The electrical strength tests were analyzed by the statistical distribution of Weibull, and the maximum likelihood method. The high concentrations present lower values to electrical strength. The ${\beta}$ parameter could be using to insulator particles dispersion. The TiO2 concentration variation shows that these incorporations implicate strength values increase has a maximum (5,35MV/cm). High pigment concentration induces a little falls in property values. Observing the ${\beta}$ parameter, minimum experiment electric field (Ebmin) and electric strength value, found that the best electric perform formulation was the formulation with 2.5% TiO2 weight.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.454-454
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• 2007

Eye Glass Display (EGD) with microdisplay to realize the virtual display can make the large screen, so virtual image has been developed by using microdisplay panel. This paper shows study of spherical prism lens design and manufacture of a small size and light weigh EGD with 0.59" OLED panel. Code V is used and it designed an aspherical prism lens about eye relief 25mm and 42 degree of filed of view (FOV). With the application this aspheric prism lens to OLED type's microdisplay, virtual image showed 60 inch at 2m. It had less than 2% of distortion value and modulation transfer function in axial had 30% of resolution with 32 lp/mm spatial frequency. We made an injection molding bases to lens designed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.698-701
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• 2005

We have investigated experimentally a nano patterning using electron beam lithography for the nickel stamper fabrication. Recently, DVD and Blu-ray disk(BD) have nano-scale patterns in order to increase the storage density. Specially, BD has 100nm-scale patterns which are generally fabricated by electron beam lithography. In this paper, we found optimum condition of electron-beam lithography for 100nm-scale patterning. We controlled various conditions of EHP(acceleration voltage), beam current, dose and aperture size in order to obtain optimum conditions. We used 100nm-thick PMMA layer on a silicon wafer as photoresist. We found that EHP was the most dominant factor in electron-beam lithography.

• 대한기계학회논문집A
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• 제26권4호
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• pp.637-643
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• 2002

The objective of this study is to provide a simple methodology to find optimum processing conditions to fabricate sub-micron structured DVD-RAM substrates with superb optical and geometrical properties. It was fecund that the birefringence, which is regarded as one of the most important optical properties for an optical disk, was very sensitive to the mold wall temperature history. Also, the integrity of the replication, represented by the land-groove structure and the radial tilt were influenced by the mold temperature and the compression pressure. A set of optimum conditions were obtained by applying Design of Experiment and the objective functions composed of three different objectives.

• 한국염색가공학회지
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• 제32권4호
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• pp.274-280
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• 2020

This study compared the mechanical properties of bamboo fiber composites and kenaf fiber composites through physical treatment (ultrasonic treatment). Kenaf, a composite of PP reinforced with bamboo fiber, was made using injection molding technology. PP was used as a binder and the ultrasonic treatment time of bamboo and kenaf was increased by 30 minutes to compare and study various mechanical properties of bamboo and kenaf composites through physical treatment. Interfacial properties such as internal cracks and internal structure of the wave cross section were confirmed using a scanning electron microscope (SEM). As a result of the ultrasonic treatment, most of the characteristics were fragile as the ultrasonic treatment time was increased, and it was confirmed that the natural characteristics of the twisted fibers had a great influence on the characteristics of the composite material.

• 소성∙가공
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• 제31권5호
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• pp.290-295
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• 2022

Recently, the use of high-tech ceramic parts in functional electronic parts, automobile parts and semiconductor equipment parts is increasing. These ceramics materials are required to have high reproducibility, reliability, large size and complex shapes. The researchers initiated the work to develop a new shaping method called gel casting, which allows high performance ceramic materials with a complex shape to be produced. The manufacturing process parameters of gel casting include uniform mixing of the initiator, bubble removal, and slip injection. In this study, we analyzed the dispersion and gelation characteristics according to the change in the additive content of the alumina slurry in the gel casting process. The alumina slurry for gel casting was prepared by mixing a solvent, a monomer and a dispersant through a ball mill. Alumina powder and a gelation initiator were added to the mixed solution, and ball milling was performed for 24 hours. A viscosity of 6,435 cps and a stable zeta potential value were obtained under the conditions of alumina powder content of 55 vol% and dispersant 2.0 wt%. After curing for 12 hours by adding aps 0.1wt%, TEMED 0.2wt%, and Monomer 3, 5wt%, it was possible to separate from the molding cup, confirming that the gelation was completed.