• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.137-137
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• 2000

The surface collective modes of thin K films deposited on Al(111) have been investigated using frequency dependent photoyield measurements and momentum resolved inelastic electron scattering. Jellium based theoretical calculations have predicted a richer set of features in the thin films than for the surface of a semi-infinite solid because there are th interference between two interfaces (substrate-film and film-vacuum) and heavy damping on the substrate. The use of an optical probe and electron scattering has allowed us to draw a more complete picture of the dynamic screening in thin films. The number, dispersion, damping and optical activity of the collective modes of the thin films have been measured as a function of K film thickness. New overlayer-induced excitations are observed : At qII=0, they correspond to the antisymmetric slab mode and the multipole surface plasmon. At finite qII=0, these modes undergo a transition towards the K multipole and monopole surface plasmons. With increasing coverage, the overlayer excitations turn into the collective modes of semi-infinite K. For a consistent interpretation of photoyield and electron energy loss spectra it is crucial to account for the non-analytic dispersion of the overlayer modes at small parallel wave vectors and for the finite angular resolution of the detector. The observed dispersions confirm predictions based on the time-dependent density functional approach.

• Asian-Australasian Journal of Animal Sciences
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• 제5권3호
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• pp.475-480
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• 1992

The effect of mechanical factors and season of the year on milking characteristics (milk yield, time of milking, rate of milk flow, stripping time and tripping milk) were studied on 26 Holstein Friesian cows, raised under Saudi Arabia environmental conditions. Cows were in the third and fourth lactation and reached the peak. Cows milked twice a day with equal intervals. Three vacuum levels (34, 38 and 42 cfm) and two pulsation ratios were used to form six vacuum-pulsation combinations. The study was carried during two seasons Autumn-Winter (S1) and Spring-Summer (S2). After absorbing the cow equations least square analysis was used to analyze the data. Vacuum level 38 cfm and pulsation ratio 70:30 was the best among all combinations of vacuum level-pulsation ratio. No significant effect (p < .01) for season, up to the seventh half minute, on the rate of milk flow. However, season of the year has a significant effect on total milk yield, stripping time and stripping milk.

• 생명과학회지
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• 제12권5호
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• pp.535-543
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• 2002

해파리 반건품의 제조를 위한 최적 냉풍건조조건을 구하고 이 조건에서 제조한 제품의 저장성을 검토한 결과, 해파리 반건품의 제조를 위해서는 시중에서 구입한 염장해 파리를 냉수에서 침지액을 교환하면서 3분씩 3회 박박 문질러서 수세한 다음 $25^{\circ}C$에서 90분간 건조하는 것이 가장 양호하였다. 또한 이 조건에서 제조한 제품을 적층필름포 장지 (Ny/PE/LLDPE 0.015/0.04s/0.040 mm)로써 각각 함기포장 및 진공포장하고 6주 동안 각각 4$^{\circ}C$ 및 2$0^{\circ}C$에서 저장하면서 제품의 저장성을 실험한 결과 4$^{\circ}C$ 저장의 경우 진공포장시료에서는 6주까지 전체의 저장기간을 통하여 품질이 양호하였으나 함기포장시료에서는 저장 4주까지 품질이 양호하였으며 5주째부터는 품질이 크게 떨어졌다. 2$0^{\circ}C$ 저장에서는 진공포장 및 함기포장시료 모두 포장방법에 관계 없이 저장 3주까지는 품질이 양호하였으나 저장 4주째부터는 모두 품질이 불량한 것으로 나타났다.

• 대한기계학회논문집B
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• 제28권11호
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• pp.1359-1367
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• 2004

The demand of vacuum pump has been increased in the process of semi-conduct manufacturing, as a core component. The response of the system for vacuum pump performance test can be utilized to assess the system and to obtain the reliability of the apparatus for the test. The system consists of gas supply tank, pressure chamber, measurement chamber and transmission line. Transient analysis for compressible fluid has been conducted to evaluate the dynamic characteristic of the volume terminated transmission line. Numerical approach based on the method of characteristics is used for the analysis. The response is evaluated with the important parameters for the system: i.e., length and diameter of the line, volume of the terminal tank. Using the numerical results, pumping speeds are calculated and then compared to the experimental results.

• Journal of Biosystems Engineering
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• 제36권6호
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• pp.434-443
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• 2011

A large scale seeding system was stable in terms of techniques but a convenient seeding system of small size was unsettled. This study was performed to develop a semi-automatic seeder for small and medium sized scale farm. To investigate optimum needle diameter and vacuum pressure was used vacuum suction needle seeder. Although the needle diameter according to the kinds of seed was different, the needle diameter for salvia and lettuce seed was suitable for 0.34 mm needle nozzle and 0.4 mm taper nozzle. The prototype consisted a seeding frame attached with needle nozzle, seed hopper, vibrating device, seeding part, vacuum ejector, seed tube etc.. As the result with the experiments, the seeding rate of the seeder was 92% and more at 0.34 mm diameter needle nozzle and 0.4 mm taper nozzle. Eccentric weight for seed hopper vibration was suitable that weight is 11 g and eccentric distance is 0.5 mm. Vibration acceleration of upward direction was 0.363 m/$s^2$. Working capacity of the seeder was possible 160 trays per hour. It was possible for sowing small seeds but it was required to make compact and simple model.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.112-120
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• 2008

Today, the use of a vacuum cleaner gave us the higher quality of life than past time, but sometimes made us w1comfortable in the house because of the specific noise that is annoying. So we need to study how sound absorbtion materials affect sound power level and sound quality with sound metrics. In this paper, we will measure and calculate sound power level for vacuum cleaner and analyze characteristics of the noise for 10 Signals according to materials positioned in vacuum cleaner. The multiple regression analysis can estimate the nonlinear characteristics of relation between subjective evaluation and sound metrics. So we will develop sound quality index for vacuum sound.

• 반도체디스플레이기술학회지
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• 제11권2호
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• pp.63-69
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• 2012

As decreasing size of chips, the need of wafer level packaging is increased in semi-conductor and display industries. Temperature uniformity is a crucial factor in vacuum soldering process to guarantee quality of bonding between chips and wafer. In this paper, a stepwise iterative algorithm has been suggested to obtain output profile of each heat source. Since this algorithm is based on open-loop stepwise iterative experimental technique, it is easier to implement and cost effective than real time feedback controls. Along with some experiments, it was shown that the suggested algorithm can remarkably improve temperature uniformity of wafer during whole heating process compared with the ordinary manual trial-and error method.

• 한국진공학회지
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• 제12권2호
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• pp.93-104
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• 2003

저진공펌프의 내구성평가와 관련하여 펌프의 성능이나 상태의 저하에 관한 기술적 근거를 확보함으로써 펌프의 운전상태를 진단할 수 있는 기초기술을 확보할 수 있으며, 이는 진공펌프의 기계적 결함 및 성능평가 장치의 동적 응답과 신뢰도 구축에 중점을 두고 신호 분석을 통하여 실험적으로 기계적인 동적 특성을 확인하는 과정을 통하여 수행할 수 있다. 저진공펌프의 압축일에 소요되는 전력을 이론적으로 규명하고 펌프의 압축일을 계산하였으며, 소비전력에 대한 진공펌프의 에너지 효율을 예측하여 펌프 노화에 따르는 소비전력의 증가 원인을 규명하는 자료로 활용할 수 있다. 또한 저진공펌프의 가동 중에 측정한 진동, 압력신호, 배기속도 및 소비전력을 측정하고 분석하여 펌프 운전상태를 감시하는데 매우 유용한 인자가 무엇인지 확인하였으며 추후 연구의 방향과 내구성평가의 기초기술을 확보하였다.

• 한국산학기술학회논문지
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• 제13권3호
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• pp.1002-1007
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• 2012

Pillar의 제조 방법은 진공유리 및 반도체 디스플레이 분야에서 사용되는 핵심공정 중 하나이다. Pillar는 스크린 인쇄 방식을 통하여 배치할 수 있으나 시료의 성분에 따라 메탈마스크의 패턴을 전부 통과하지 못하거나 점도에 따라 통과된 혼합물이 본래의 형상을 유지 못하는 경우가 발생한다. 본 연구에서는 알루미나와 실리카 기반의 무기화합물을 이용하여 스크린 인쇄를 통해 pillar를 배치하였다. 실험계획법의 하나인 혼합물 설계를 이용함으로써 실험횟수를 줄이고 진공유리 pillar의 조성을 설계할 수 있는 방법을 제시하고자 한다.

• 공업화학
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• 제22권6호
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• pp.664-671
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• 2011

무촉매 공기 브로잉 공정에서 석유계 감압 잔사유로부터 세미-부로운 아스팔트를 제조하는 경우, 시간에 따른 아스팔트의 조성, 구조, 물리적 성질의 변화를 조사하였다. 공기 브로잉에 의해 지방족 탄화수소 성분이 방향족 탄화수소 성분으로 전이되고, 고분자화 되어 아스팔텐 성분이 증가함을 박막크로마토그래피를 이용한 조성 분석에서 관찰하였다. 처리시간에 따른 방향족화와 고분자화 정도의 증가는 $^1H-NMR$, 열시차분석, 그리고 열중량분석에서도 확인할 수 있었다. 이러한 아스팔트의 조성과 구조의 변화는 침입도의 감소, 연화점과 인화점의 증가를 초래하였다.