• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
• /
• pp.186-186
• /
• 2000

After LeComber et al. reported the first amorphous hydrogenated silicon (a-Si: H) TFT, many laboratories started the development of an active matrix LCDs using a-Si:H TFTs formed on glass substrate. With increasing the display area and pixel density of TFT-LCD, however, high mobility TFTs are required for pixel driver of TF-LCD in order to shorten the charging time of the pixel electrodes. The most important of these drawbacks is a-Si's electron mobiliy, which is the speed at which electrons can move through each transistor. The problem of low carier mobility for the a-Si:H TFTs can be overcome by introducing polycrystalline silicon (poly-Si) thin film instead of a-Si:H as a semiconductor layer of TFTs. Therefore, poly-Si has gained increasing interest and has been investigated by many researchers. Recnetly, fabrication of such poly-Si TFT-LCD panels with VGA pixel size and monolithic drivers has been reported, . Especially, fabricating poly-Si TFTs at a temperature mach lower than the strain point of glass is needed in order to have high mobility TFTs on large-size glass substrate, and the monolithic drivers will reduce the cost of TFT-LCDs. The conventional methods to fabricate poly-Si films are low pressure chemical vapor deposition (LPCVD0 as well as solid phase crystallization (SPC), pulsed rapid thermal annealing(PRTA), and eximer laser annealing (ELA). However, these methods have some disadvantages such as high deposition temperature over $600^{\circ}C$, small grain size (<50nm), poor crystallinity, and high grain boundary states. Therefore the low temperature and large area processes using a cheap glass substrate are impossible because of high temperature process. In this study, therefore, we have deposited poly-Si thin films on si(100) and glass substrates at growth temperature of below 40$0^{\circ}C$ using newly developed high rate magnetron sputtering method. To improve the sputtering yield and the growth rate, a high power (10~30 W/cm2) sputtering source with unbalanced magnetron and Si ion extraction grid was designed and constructed based on the results of computer simulation. The maximum deposition rate could be reached to be 0.35$\mu$m/min due to a high ion bombardment. This is 5 times higher than that of conventional sputtering method, and the sputtering yield was also increased up to 80%. The best film was obtained on Si(100) using Si ion extraction grid under 9.0$\times$10-3Torr of working pressure and 11 W/cm2 of the target power density. The electron mobility of the poly-si film grown on Si(100) at 40$0^{\circ}C$ with ion extraction grid shows 96 cm2/V sec. During sputtering, moreover, the characteristics of si source were also analyzed with in situ Langmuir probe method and optical emission spectroscopy.

• 한국응용과학기술학회지
• /
• 제34권2호
• /
• pp.305-314
• /
• 2017

본 연구는 마이크로파 저온진공건조 기술을 이용하여 고효율 인삼개발을 하고자 하였다. 홍삼 제조 공정에서 증삼 후 $60-70^{\circ}C$에서 24시간 동안 건조하고 다시 $40^{\circ}C$에서 72시간동안 건조한 열풍 건조 홍삼과 증삼 후 마이크로파 저온진공건조기에서 900 watt, 2.45 MHz, 50 mmHg 조건으로 5시간동안 건조하고 다시 750 mmHg로 2시간동안 건조한 홍삼으로 조직 관찰, 관능평가, 진세노사이드 및 조사포닌 함량 변화 등을 비교하였다. 그 결과, 마이크로파 저온진공 홍삼은 색도가 밝은 색으로, 표면적은 다공성 조직으로 변화하였으며, 향미를 높이고 쓴 맛을 크게 감소시킴과 동시에 단 맛을 증가시켜 종합적인 선호도를 높였다. 또한, 단시간에 진세노사이드 $Rg_1$과 $Rb_1$ 함량을 열풍 건조 홍삼에 비해 1시간대에서 약 6배, 8배가 증가되었으나, $Rg_3$ 함량에서는 큰 차이가 나타나지 않았다. 마지막으로 조사포닌 함량은 10-20분대부터 크게 증가하여 이후 지속적으로 높은 함량이 나타났다. 이와 같은 결과를 종합해보면, 마이크로파 저온진공홍삼은 열풍 건조 홍삼에 비해 다공성 조직 변화를 통해 단시간에 진세노사이드 및 조사포닌에 대한 추출 수율을 높이고 향미와 식감을 개선시켜 홍삼에 대한 선호도를 높일 수 있음을 확인되었다.

• 문화기술의 융합
• /
• 제7권4호
• /
• pp.845-855
• /
• 2021

본 연구는 보성에서 재배된 녹차잎을 감압증류와 열수추출법으로 추출하여 항산화, 항주름, 미백, 항균 in vitro 실험과 HPLC 분석을 수행하였다. 보성녹차 감압증류추출물은 주름개선(Elastase 활성 저해 실험)과, 미백(Mushroom tyrosinase 활성 저해 실험) 효능에서 우수한 결과를 나타내었으며, 열수추출물보다 낮은 농도에서 IC50 값이 측정되었다. 보성녹차 열수추출물은 항산화 시험(DPPH, ABTS+ radical 소거능, SOD 유사활성능, 총 폴리페놀 함량)에서 우수한 결과를 나타내었다. 항균 실험에서는 보성녹차 열수추출물에 의해 Staphylococcus aureus, Cutibacterium acnes 균주에 대하여 Clear zone이 형성되었다. HPLC 분석 결과로, EGCG와 Caffeine이 열수추출물에서 40.29 mg/g, 9.94 mg/g 검출되었고, 감압증류추출물에서는 Caffeine이 3.4 mg/g 검출되었다. 따라서 보성녹차 감압증류추출물은 주름개선과 미백효과가 탁월하며, 보성녹차 열수추출물은 항산화, 항균효과가 우수함을 확인하였다.

• Journal of Electrical Engineering and Technology
• /
• 제1권3호
• /
• pp.359-365
• /
• 2006

Since the start of the KSTAR (Korea Superconducting Tokamak Advanced Research) project, Instrumentation and Control (I&C) of the Neutral Beam Test Facility (NB-TF) has been striving to answer diverse requests arising from various facets during the project's development and construction phases. Hard-wired electrical circuits have been designed, tested, fabricated, and finally installed to the relevant parts of the system. In relation to the vacuum system I&C, controlling functions for the rotary pumps, a Roots pump, two turbomolecular pumps, and four cryosorption pumps have been constructed. I&C for the ion source operation are the temperature and flow rate signal monitoring, Langmuir probe signal measurements, gradient grid current measurements, and arc detector circuit. For the huge power system to be monitored or safely operated, many temperature measurement functions have also been implemented for the beam line components like the neutralizer, bending magnet, ion dump, and calorimeter. Nearly all of the control and probe signals between the NB test stand and the control room were made to be transmitted through the optical cables. Failures of coolant flow or beam line vacuum pressure were made to be safely blocked from influencing the system by an appropriate interlock circuit that will shut down the extraction voltage application to the system or prevent damages to the vacuum components. Preliminary estimation of the beam power through the calorimetric measurement shows that 87.9% of the total power of the 60kV/18A beam with 200 seconds duration is absorbed by the calorimeter surface. Most of these I&C results would be highly appropriate for the construction of the main NBI facility for the KSTAR national fusion research project.

• Clinical and Experimental Pediatrics
• /
• 제61권12호
• /
• pp.387-391
• /
• 2018

Purpose: Subgaleal hemorrhage (SGH) is a rare but potentially fatal condition in newborns; however, few studies have reported on this condition. We aimed to identify the clinical characteristics and prognostic factors of SGH. Methods: We retrospectively reviewed the medical records of 20 neonates diagnosed with SGH between January 2000 and June 2017. Enrolled neonates were clinically diagnosed when they had tender fluctuant scalp swelling that crossed the suture lines. Results: Among 20 neonates with SGH, 12 were boys and 7 were girls; median hospitalization duration was $9.7{\pm}6.9days$. Fourteen neonates (70%) were born via vacuum-assisted vaginal delivery, and 4 via vacuum-assisted cesarean section. Of the neonates enrolled, half of them initially showed unstable vital signs, including apnea, desaturation, and cyanosis. Ten neonates had acidosis and 3 had asphyxia (pH<7.0). Intracranial lesions associated with SGH were observed in 15 neonates (75%), including subdural hemorrhage (50%), subarachnoid hemorrhage (15%), intraventricular hemorrhage (5%), cerebral infarct (15%), skull fracture (30%), and cephalohematoma (20%). Twelve neonates (60%) required transfusion, 5 (25%) had seizures, and 3 (15%) died. Eight neonates (40%) had hyperbilirubinemia (mean total bilirubin, $13.1{\pm}7.4$). The mean follow-up period was $8.4{\pm}7.5months$. At follow-up, 10 neonates (58.8%) were healthy with normal development, whereas 7 (41.2%) had neurological deficits. Conclusion: The morbidity rate was 41.2% due to severe metabolic acidosis. Anemia, hyperbilirubinemia, low Apgar scores, and subdural hemorrhage did not affect the prognosis. The long-term outcomes of neonates with SGH are generally good. Only arterial blood pH was significantly associated with death.

• 분석과학
• /
• 제29권1호
• /
• pp.29-34
• /
• 2016

염소로 소독된 음용수에서 수백 ng/L의 농도까지 검출되는 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone(MX)를 시료 농축 후 액-액 추출(LLE), 메틸 유도체화 및 GC-MS로 정량 분석하였다. 4 L의 물 시료를 감압회전증발기를 사용해 30 ℃에서 0.4 L로 농축하였다. 물 중의 MX는 ethyl acetate(100 mL × 2)를 용매로 사용하여 추출하였으며, 추출액 중 MX는 10 % H₂SO₄ in methanol로 methyl 유도체를 만들었다. MX의 회수율은 73.8 %이었으며, 이는 수지 흡착법의 38.1 %보다 높았다. 정량한계와 반복성(RSD)은 각각 10 ng/L와 2.2 %로 추정되었다. 이 결과는 시간이 더 많이 소요되는 수지 흡착법의 대체 방법으로 LLE가 사용될 수 있다는 것을 보여 주었다.

• 한국지반공학회논문집
• /
• 제37권8호
• /
• pp.51-58
• /
• 2021

최근 우리나라는 미국항공우주국이 주도하는 유인 달 탐사 프로젝트인 아르테미스 프로그램에 10번째 국가로 참여하게 되면서 다방면에서 유관연구를 수행하고 있다. 특히, 달의 극지방에는 동결토 형태로 다량의 물이 존재하는 것으로 밝혀지면서 이를 자원으로 활용하기 위한 연구들이 활발히 진행되고 있다. 달 표면에 자리 잡고 있는 월면토의 열전도도에 관한 정보는 얼음 존재 추정 및 취득을 위한 열 채굴 기술 등에 활용될 수 있다. 본 연구에서는 지반열진공 챔버를 활용하여 진공압에 따른 한국형 인공월면토(KLS-1)의 열전도도를 측정하였다. 기존 연구에서 밝혀진 인공월면토(JSC-1A)와 비교분석을 통해 한국형 인공월면토의 유효성을 재확인하였으며, 건조단위중량 및 진공압에 따른 열전도도 추정이 가능한 경험적 예측모델을 제안하였다. 본 연구에서 도출된 결과는 진공 챔버를 이용한 달 행성의 극저온 환경 구현 시 활용이 가능할 것으로 판단된다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2002년도 ITC-CSCC -2
• /
• pp.786-789
• /
• 2002

A recurrent artificial neural network (ANN) model is developed to simulate hydrocarbon recovery process at petroleum-contaminated site. The groundwater extraction rate, vacuum pressure, and saturation hydraulic conductivity are selected as the input variables, while the cumulative hydrocarbon recovery volume is considered as the output variable. The experimental data fer establishing the ANN model are from implementation of a multiphase flow model for dual phase remediation process under different input variable conditions. The complex nonlinear and dynamic relationship between input and output data sets are then identified through the developed ANN model. Reasonable agreements between modeling results and experimental data are observed, which reveals high effectiveness and efficiency of the neural network approach in modeling complex hydrocarbon recovery behavior.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2009년도 춘계학술대회 논문집
• /
• pp.101-101
• /
• 2009

진공아크소스의 거대입자 제거를 위하여 이중 굽힘형 자장여과 아크 소스를 제작하였다. 소스의 각 전자석의 역할을 조사하고, 발전 안정화 영역에 대한 연구를 수행하였다. 또한 이중 굽힘 자장여과아크소스의 아크방전전압, 주입가스의 위치, 유량 및 플라즈마 덕트의 전압에 따른 인출 이온빔의 공간적 분포 및와 에너지 분포에 대한 연구를 진행하였다. 압력 0.1 mtorr에서 인출 이온빔의 평균에너지는 45$\sim$50 eV를 나타내었으며, 압력이 증가함에 따라 감소하는 경향을 보였다.

• Natural Product Sciences
• /
• 제9권3호
• /
• pp.154-157
• /
• 2003

In the present study, the roots of Sesbania grandiflora L. Poiret (Papilionaceae) were successively extracted with petroleum ether (PE), chloroform (CE), methanol (ME) and water (AE) by soxhlet extraction. The extracts were vacuum dried and screened for analgesic, antidiarrhoeal, antibacterial (Staphylococcus epidermidis, Staphylococcus aureus, Micrococcus luteus, Bacillus cereus, and Klebsiella pneumonia) and antifungal (Candida albicans and Aspergillus niger) activity. All the extracts exhibited potent, dose dependant (40 and 80 mg/kg) and significant analgesic and antidiarrhoeal activity in the order of AE>PE>CE>ME and ME>PE>AE>CE respectively. AE at the experimental dose was found to exhibit more potent analgesic activity than standard drug. All the extracts exhibited significant antibacterial $(100\;{\mu}g/ml)$ and antifungal activity $(50\;and\;100\;{\mu}g/ml)$. ME exhibited the most potent antibacterial activity.