• Transactions of Materials Processing
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• v.8 no.5
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• pp.491-497
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• 1999

The effect of partial squeeze on the quality of casting products in the vacuum die casting was investigated to make defect free casting products with excellent mechanical properties. The partial squeeze and vacuum die casting process was industrially implemented in making reaction shaft support which was made of a hypereutectic Al-15%Si alloy. To combine squeezing and vacuum effects, the plunger injection system was designed and attached on the chill vent type vacuum machinery system. The combination of vacuum effect before injection and partial squeezing effect after injection resulted in defect free die casting products. The uniform distribution of fine eutectic and proeutectic Si obtained from trial process also provided excellent mechanical properties.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.28-30
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• 2009

PDP panels with MgO protective layer are manufactured by using the "all-in-vacuum" process we have established [1]. This is the process aiming to keep the MgO surface as clean as possible after the evaporation. The panels are evaluated in term of discharge voltage, aging time, luminance, luminous efficacy, discharge time-lag. It is confirmed that the "all-in-vacuum" process particularly improves the aging time, discharge voltage and the discharge time-lag.

• Proceedings of the Korean Vacuum Society Conference
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• 1997.02a
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• pp.98-99
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• 1997

• Particle and aerosol research
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• v.11 no.4
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• pp.93-98
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• 2015

Particles which generated from plasma enhanced chemical vapor deposition (PECVD) during thin film deposition process can affect to the process yield. By using light extinction method, ISPM can measure particles in the large-diameter pipe (${\leq}300mm$). In our research, in-situ particle monitor (ISPM) sensor was installed at the 300 mm diameter exhaust-line to count the particles in each size. In-house flange for mounting the transmitting and receiving parts of ISPM was carefully designed and installed at a certain point of exhaust line where no plasma light affect to the light extinction measurement. Measurement results of trend changes on particle count in each size can confirm that ISPM is suitable for real-time monitoring of vacuum process.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.703-706
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• 2004

This paper deals with the various sealing conditions in a vacuum and the discharge characteristics. The MgO thin film is prepared by e-beam evaporation method. Sealing process was performed in a vacuum at panel temperature of 430 $^{\circ}C$. We find the cracks on the MgO film surface, which results in higher discharge voltage and lower luminous efficiency. The vacuum in-line sealing technology does not require additional annealing process but induces the MgO cracks because of the high temperature sealing cycle in a vacuum. Therefore we modify the vacuum in-line sealing cycle which the MgO cracks are not found and the good characteristics of plasma displays are found in higher sealing pressure at sealing temperature of 430 $^{\circ}C$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.777-780
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• 2005

The high vacuum in a electron beam lithography is basic condition, because electron beam vanish by collision with air molecules in generally atmosphere. To make high vacuum state, the vacuum control valve is essential. Most vacuum control valve are manual units. So, user of manual vacuum valve must have understanding vacuum process to change from low vacuum to high vacuum state. The user of electron beam lithography are troubled with operation of manual vacuum valve, in case the vacuum chamber is frequently open. In this paper, the design and performance test of auto vacuum control valve for electron beam lithography are described. With the auto vacuum control valve, the high vacuum level can reach 2.8E-5 Torr.

• The Korean Journal of Food And Nutrition
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• v.11 no.5
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• pp.536-541
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• 1998

This study was carried out to investigate the changes of characteristics of myofibrillar protein for the vacuum chilled, the air frozen or the rechilled Holstein beef loin. The vacuum chilled beef was stored at 1$^{\circ}C$ and the air frozen beef was stored at -20$^{\circ}C$ for 60 days. The rechilled beef was restored for 3 days at 1$^{\circ}C$ by using the vacuum chilled or the air frozen beef. Myofibrillar protein extractability, 30,000 dalton component content and Mg-ATP ase activity for the vacuum chilled beef were higher than those of the air frozen beef. Each parameters increased significantly for the vacuum chilled beef after the 20 days storage, but there was no significant difference for the vacuum chilled beef after the 20 days storage, but there was no significant difference for the air frozen beef during the 60 days storage. By the rechilling process, myofibrillar protein extractability of the vacuum chilled and the frozen beef were not significant difference. The 30,000 dalton component of the vacuum chilled beef was showed not significant increment by rechilling, but the frozen beef was showed significant increment by rechilling. The Mg-ATPase activity of myofibrillar protein of the vacuum chilled beef was not changes by rechilling, but the frozen beef after the 20 days storage was significant increment by rechilling.

• Journal of the Semiconductor & Display Technology
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• v.10 no.4
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• pp.101-106
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• 2011

There are various methods in the flat panel display manufacture. The cost reduction effect is very big in case of using the screen printing method. The screen printing method is much used in the process of forming PDP barrier and can apply to the process of arranging the pillars for maintaining the vacuum gap of the vacuum glazing panel. The pillar which is one of the core elements for comprising vacuum glazing maintains the vacuum gap overcoming the vacuum pressure difference with the atmospheric pressure generated in vacuum glazing. At the same time, the deformation phenomenon by vacuum pressure is relived. In this paper, by using FEM about three considered in the pillar design and arrangement kinds of limiting factors, the simulation was performed. The pillar optimum arrangement method at within the maximum allowable tensile stress and heat transfer coefficients according to the arrangement try to be presented based upon the analyzed result data review and this validity tries to be verified by FEM.

• Structural Engineering and Mechanics
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• v.72 no.3
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• pp.305-312
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• 2019

This paper investigates the effect of utilizing vacuum bagging process to enhance the bond behavior between fiber reinforced polymer (FRP) composites and concrete substrate. Sixty specimens were prepared and tested using double-shear bond test. The effect of various parameters such as vacuum, fiber type, and FRP sheet length and width on the bond strength were investigated. The experimental results revealed that utilizing vacuum leads to improve the bond behavior between FRP composites and concrete. Both the ultimate bond forces and the maximum displacements were enhanced when applying the vacuum which leads to reduction in the amount of FRP materials needed to achieve the required bond strength compared with the un-vacuumed specimens. The efficiency of the enhancement in bond behavior due to vacuum highly depends on the fiber type; using carbon fiber showed higher enhancement in the bond strength compared to the glass fiber when vacuum was applied. On the contrary, specimens with glass fiber showed higher enhancement in the maximum slippage compared to specimens with carbon fibers. Utilizing vacuum does not affect the debonding failure modes but lead to increase in the amount of attached concrete on the surface of the debonded FRP sheet.

• Journal of the Semiconductor & Display Technology
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• v.12 no.2
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• pp.45-50
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• 2013

This paper focuses on the fundamental issues for improving the efficiency and throughput of the AC PDP (Plasma Display Panel) manufacturing. The properties of the MgO protective layer affect the PDP efficiency. Especially, the secondary electron emission efficiency was affected on the deposition rate of MgO during the evaporation. In this study, the deposition rate of 5 $\AA$/s has given the maximum efficiency value of 0.05 It is demonstrated that the impurity gases such as $H_2O$, $CO_2$, CO or $N_2$, and $O_2$ can be remained inside the PDP panel before sealing and the amount of the impurity gases decreased rapidly as the base vacuum level increased, especially near $10^{-5}$ torr. The fundamental solution in order to overcome these problems is the vacuum in-line sealing process from the MgO evaporation to the final sealing of the panel without breaking the vacuum. We have demonstrated this fundamental process technology and shown the feasibility. The firing voltage was reduced down to 285 V at the base vacuum value of $10^{-6}$ torr, whreras it was about 328 V at the base vacuum value of $10^{-3}$ torr.