• 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 Korean Society for Aeronautical & Space Sciences
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• v.38 no.8
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• pp.842-847
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• 2010

Thermal analysis for the simulation of satellite component level thermal vacuum test processes was carried out by considering thermal vacuum test environment condition, thermal vacuum chamber configuration, and satellite's inner thermal environment. The transient analysis results can be obtained for the temperatures of component and thermal vacuum chamber assemblies. The thermal analysis model was verified with the component thermal environmental test results by using enhanced thermal vacuum chamber.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.320-320
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• 2013

Film thickness monitoring with plasma impedance monitoring (PIM) is demonstrated for small area $SiO_2$ RF plasma etching processes in this work. The chamber conditions were monitored by the impedance signal variation from the I-V monitoring system. Moreover, modified principal component analysis (mPCA) was applied to estimate the $SiO_2$ film thickness. For verification, the PIM was compared with optical emission spectroscopy (OES) signals which are widely used in the semiconductor industry. The results indicated that film thickness can be estimated by 1st principal component (PC) and 2nd PC. Film thickness monitoring of small area $SiO_2$ etching was successfully demonstrated with RF plasma harmonic impedance monitoring and mPCA. We believe that this technique can be potentially applied to plasma etching processes as a sensitive process monitoring tool.

• Journal of the Korean Vacuum Society
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• v.15 no.4
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• pp.338-346
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• 2006

In semiconductor process, it is so hard to predict an exact failure point of the vacuum pump due to its harsh operation conditions and nonlinear properties, which may causes many problems, such as production of inferior goods or waste of unnecessary materials. Therefore it is very urgent and serious problem to develop diagnostic models which can monitor the operation conditions appropriately and recognize the failure point exactly, indicating when to replace the vacuum pump. In this study, many influencing factors are totally considered and eventually the monitoring model using multivariate statistical methods is suggested. The pivotal algorithms are Multiway Principal Component Analysis(MPCA), Dynamic Time Warping Algorithm(DTW Algorithm), etc.

• Transactions of Materials Processing
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• v.21 no.3
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• pp.195-201
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• 2012

A vacuum ladling die casting system is suggested as a means to obtain a high vacuum level. A high vacuum of 17.8 mmHg is obtained by sealing the inner space of the mould. The sample product is a rear-head housing for an auto-compressor, and the die-casting with 6-cavities was conducted. The flow analysis shows that the filling speed during vacuum ladling is faster than for a non-vacuum system. The air holes in the sample product were too small to be seen with the naked eye in X-ray films. Density tests show that the high vacuum ladling system reduces the internal porosity as much as 57.8% when compared to the non-vacuum system. A defective rate of only 0.17% was found from leak testing. The results of this research prove that the high vacuum die-casting process is useful for manufacturing of aluminium components under high internal pressure.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.59-59
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• 2012

Vacuum pumping remains central to the performance and economy of many manufacturing processes, scientific instruments and scientific research. More vacuum is being used in many of the latest or leading edge manufacturing processes: Current examples include 3D semiconductor devices, EUV lithography, 450 mm silicon wafers, AMOLED displays, LEDs, Lithium-ion batteries and steel degassing. In other applications, vacuum pumping technology developments have led to much lower product costs which for example have enabled mass spectrometers to become a ubiquitous tool is life science research. Vacuum pumps have continuously evolved during the past 100 years of vacuum-based industrial processing but remain a key component which is often on the critical path of process and product improvements. This is especially so in the growing number of applications where the pumps are highly stressed. This presentation outlines significant developments in vacuum that have brought about this progress. The likely course of continued improvements is discussed in terms of increased performance and reliability, robust by-product handling, better cost efficiency and reduced environmental impact especially power consumption.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.153-153
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• 2012

Endpoint detection with plasma impedance monitoring and self-plasma optical emission spectroscopy is demonstrated for dielectric layers etching processes. For in-situ detecting endpoint, optical-emission spectroscopy (OES) is used for in-situ endpoint detection for plasma etching. However, the sensitivity of OES is decreased if polymer is deposited on viewport or the proportion of exposed area on the wafer is too small. To overcome these problems, the endpoint was determined by impedance signal variation from I-V monitoring (VI probe) and self-plasma optical emission spectroscopy. In addition, modified principal component analysis was applied to enhance sensitivity for small area etching. As a result, the sensitivity of this method is increased about twice better than that of OES. From plasma impedance monitoring and self-plasma optical emission spectroscopy, properties of plasma and chamber are analyzed, and real-time endpoint detection is achieved.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.3
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• pp.158-168
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• 2015

To create an ultra-high vacuum state at the KSTAR, the temperature of plasma facing component and vacuum vessel should be maintained at $300^{\circ}C$ and $110^{\circ}C$ respectively at a baking phase. The purpose of this research is obtaining the target baking temperatures. Experiments were performed to investigate the temperature characteristics of PFC and VV at the baking phase. Thermal network analysis was used to find heat transfer rates among PFC, VV and other components, and this analysis was verified by using the experimental data. The required heating energy of the PFC and the heating and cooling energy of the VV for the target baking temperatures were found to be 346 kW, 28 kW, and 136 kW, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.144.1-144.1
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• 2015

The triggered vacuum switch(TVS) is a one of the important component in consisiting high power control systems(HPCS). The operating condition is depended on material, geometry, operating power and so on. Our research is focused on the effects of thses basic properties and ptimized condition, because these are critical conditons in understanding the TVS operation. Our experiment is accomplished with a copper electrode and a tungsten trigger pin after being assembled into a vacuum chamber. The operating voltage in our system is more than dozens of kV at the 5kV trigger pulse. Our goal is up to 300kJ, therefore the currents should be more optimized in additional experiments,

• Journal of Powder Materials
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• v.3 no.2
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• pp.91-96
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• 1996

The effect of vacuum annealing on the oxidation behavior of milled WC-15%Co powder mixture has been studied. A cobalt component in the milled powder mixture was oxidized preferentially above 175$^{\circ}C$ in air. The specimens showed a steady increase in weight at 175$^{\circ}C$ but did constant weight followed by rapid increase in specimen weight at the beginning above 20$0^{\circ}C$. Oxidation of the milled powder mixture was significantly suppressed by vacuum annealing at 30$0^{\circ}C$ for 10 h. Suppression of oxidation by vacuum annealing and different oxidation behaviors of the milled powder mixture between 175$^{\circ}C$ and 20$0^{\circ}C$, were attributed to removal of strain energy stored in the cobalt powder during vacuum annealing or oxidation treatment above 20$0^{\circ}C$. The role of stored strain energy on oxidation of milled WC-15%Co powder mixture was proved by X-ray diffraction method and differential thermal analysis.