• 한국식품영양학회지
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• 제11권5호
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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.

• 한국항공우주학회지
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• 제38권8호
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• pp.842-847
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• 2010

본 연구는 인공위성 탑재품 열진공 시험시 적용된 열환경 조건, 탑재품 시험용 열진공 챔버의 형상, 위성체 내부의 열환경들을 고려하여 열진공 시험 과정을 모사하는 수치해석모델을 설계하여 열해석을 수행하였다. 피시험체인 탑재품과 열진공 챔버 구성요소의 시간에 따른 온도 변화를 보여주는 과도적(Transient) 해석 결과를 구할 수 있다. 열해석에 의한 성능향상 설계를 반영하여 업그레이드한 열진공 챔버를 이용한 탑재품 환경시험을 수행하였으며, 시험 결과와 열해석 결과에 대한 비교/검증을 수행하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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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.

• 한국진공학회지
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• 제15권4호
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• pp.338-346
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• 2006

반도체 공정에 사용되는 진공펌프는 가혹한 운전조건과 비선형적 특성으로 인하여 고장시점을 정확히 예측해내기가 어려운데 이로 인해 불량품이 양산되거나 불필요한 재원이 낭비되는 등의 문제가 발생하게 된다. 따라서 펌프의 운전상태를 올바르게 모니터링하고 고장 지점을 정확히 인지해 적절한 펌프 교체 시점을 알려주는 진공펌프 상태진단 모델의 개발은 매우 시급하고도 중대한 문제라 할 수 있겠다. 본 연구에서는 다변량 통계기법을 이용하여 영향력 있는 인자들을 종합적으로 고려하였으며 최종적으로 Hotelling's T2 통계량을 이용한 진공펌프 상태진단 모델을 제안하였다. 핵심적인 알고리즘으로는 Multiway Principal Component Analysis(MPCA)와 Dynamic Time Warping Algorithm(DTW Algorithm) 기법 등이 사용되었다.

• 소성∙가공
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• 제21권3호
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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.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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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.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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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.

• 설비공학논문집
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• 제27권3호
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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.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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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,

• 한국분말재료학회지
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• 제3권2호
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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.