• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.186-186
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• 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.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.305-314
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• 2017

The purpose of this study was to develop the high efficiency of ginseng by using microwave low temperature vacuum drying technology. In red ginseng manufacturing processes, the study results compared the hot-air drying red ginseng dried during 24hours in $60-70^{\circ}C$ and redried during 72hours in $40^{\circ}C$ after the steaming ginseng with the red ginseng dried in microwave low temperature vacuum dryer on condition that 900 watt, 2.45 MHz, 50 mmHg during 5 hours and redried during 2 hours on 750 mmHg after the steaming ginseng about observation of tissue, sensory evaluation and a change of ginsenoside and crude saponin content. As a result, the red ginseng in microwave low temperature vacuum was had high brightness, the surface turned into porosity tissue and added more flavor, decreased bitterness highly on the contrary increased sweetness at the same time that elevated the comprehensive preference. Moreover, In a short time, the content of ginsenosides $Rg_1$ and $Rb_1$ increased about sixfold, eightfold in one time zone but there were no wide difference in content of $Rg_3$ as compared to the hot-air drying red ginseng. Finally, content of crude saponin was increased widely at 10-20 minutes and stayed high crude saponin content consistently. Therefore, this result indicated that the red ginseng in microwave low temperature vacuum increased extraction yields of the ginsenosides and crude saponin through a change of porosity tissue and improved flavor and texture compare with the general hot air dried red ginseng in a short time. According to these results, that provided that could increase the preference about red ginseng.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.845-855
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• 2021

In this study, Camellia sinensis Leaf cultivated in Boseong was extracted by vacuum distillation and hydrothermal extraction methods, and we performed in vitro experiments such as antioxidant, anti-wrinkle, whitening, and antibacterial activity test and HPLC analysis. Wrinkle improvement (elastase inhibition assay) and whitening effect (mushroom tyrosinase inhibition assay) of Boseong vacuum distilled extract have excellent results and IC50 values of vacuum distillation extract was measured at a lower concentration than that of the hydrothermal extract. The antioxidant activity of the Boseong hydrothermal extract was excellently measured in DPPH radical and ABTS+ radical scavenging activity, SOD-like activity, and total polyphenol content. In the antibacterial experiment, the Boseong hydrothermal extract formed a clear zone for the Staphylococcus aureus and Cutibacterium acnes strain. As a result of HPLC analysis, EGCG and caffeine in the hydrothermal extract were 40.29 mg/g, 9.94 mg/g respectively, and caffeine in the vacuum distilled extract was 3.40 mg/g. Therefore, we examined that Boseong Camellia sinensis vacuum distilled extract has excellent anti-wrinkle and whitening effect, and its hydrothermal extract has good antioxidant and antibacterial efficacy.

• Journal of Electrical Engineering and Technology
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• v.1 no.3
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• pp.359-365
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• 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
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• v.61 no.12
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• pp.387-391
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• 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.

• Analytical Science and Technology
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• v.29 no.1
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• pp.29-34
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• 2016

This study explores the means by which MX can be effectively extracted from chlorinated water 3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), a potent mutagen commonly found in chlorinated drinking water at concentrations of up to a few hundred ng/L, was quantitatively determined using sample enrichment followed by liquid-liquid extraction (LLE), derivatization to methylated form, and analysis with GC-MS. A 4-L water sample was enriched to a concentration of 0.4 L using a vacuum rotary evaporator at 30 ℃. MX in the water was extracted using ethyl acetate (100 mL × 2) as a solvent and MX in the extract was methylated with 10 % H₂SO₄ in methanol. MX was recovered at a rate of 73.8 %, which was higher than that (38.1 %) for the resin adsorption method. The limit of quantification and repeatability (as relative standard deviation) were estimated to be 10 ng/L and 2.2 %, respectively. This result suggested that LLE can be used for the determination of MX in chlorinated water as an alternative to more time-consuming resin adsorption method.

• Journal of the Korean Geotechnical Society
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• v.37 no.8
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• pp.51-58
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• 2021

South Korea, as the 10th country to join the Artemis program led by NASA, is actively supporting various researches related to the lunar exploration. In particular, the utilization of water as a resource in the Moon has been focused since it was discovered that ice exists at the lunar pole as a form of frozen soil. Information on the thermal conductivity of lunar regolith can be used to estimate the existence for ice water extraction by thermal mining. In this study, the vacuum pressure effect on thermal conductivity of KLS-1 was investigated with a DTVC (Dusty Thermal Vacuum Chamber). The reliability of KLS-1 was reconfirmed through comparison with thermal conductivity of known standard lunar regolith simulants such as JSC-1A. An empirical equation to assess thermal conductivity considering dry unit weight and vacuum pressure was proposed. The results from this study can be implemented to simulate lunar cryogenic environment using the DTVC.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.786-789
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• 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.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.101-101
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• 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
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• v.9 no.3
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• pp.154-157
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• 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.