• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.151-152
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• 2007

탄소나노튜브(CNTs)는 우수한 물리적, 화학적, 기계적 특성으로 다양한 분야에서 연구가 진행 되고있다. 특히, field emission displays (FEDs)로의 응용을 위해서는 기본적으로 sodalime glass 위에 직접 CNTs를 성장시켜야 하며, 소자 응용을 위해 기판인 sodalime glass를 왜곡시키는 온도보다 낮은 온도에서 CNT의 수직 성장이 이루어져야 한다. 본 연구에서는 Hot-filament plasma enhanced chemical vapor deposition (HF-PECVD)를 이용하여 합성온도를 400, 450, 500, $550^{\circ}C$로 변화시켰으며 촉매 층인 Ni의 두께를 5~40 nm까지 조절하여 탄소나노튜브를 합성하였다. 저온에서 합성된 탄소나노튜브는 FE-SEM을 이용하여 성장 형태 및 표면 특성을 확인하였으며, 미세구조는 HR-TEM을 이용하여 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.71-75
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• 2003

Carbon nanotubes(CNTs) are grown by using Co catalyst metal. CNTs fabricated by PECVD(plasma enhanced chemical vapor deposition) method are studied in terms of surface reaction and surface structure by TEM and Raman analysing method and are analysed in its electrical field emission characteristics with variation of space between anode and cathode. Acetylene($C_2H_2$) gas is used as the carbon source, while ammonia and hydrogen gas are used as catalyst and dilution gas. The CNTs grown by hydrogen($H_2$) gas plasma indicates better vertical alignment, lower temperature process and longer tip, compared to that grown by ammonia($NH_3$) gas plasma. The CNTs fabricated with Co(cobalt) catalyst metal and PECVD method show the multiwall structure in mid-circle type in tip-end and the inner vacancy of 10nm. Emission properties of CNTs indicate the turn-on field to be $2.6\;V/{\mu}m$. We suggest that CNTs can be possibly applied to the emitter tip of FEDs and high brightness flat lamp because of low temperature CNTs growth, low turn-on field.

• 방사선산업학회지
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• 제5권4호
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• pp.313-316
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• 2011

[$^{18}F$]FDG (2-[$^{18}F$] Fluoro-2-deoxy-D-Glucose), which is required Automated Synthetic Module for production, is most often used Radiopharmaceuticals in nuclear medicine. In this study, an Automated Synthesis Module was developed to produce FDG in two consecutive time when F-18 feds continuously by modifying a domestic FDG Automated Synthetic Module on structural geometry and control system. The results were showed that the Average Synthesis Yields on the developed Automated Synthetic Module were $45{\pm}3%$ (n=20), $50{\pm}3%$ (n=20) respectively. The Quality Control results, such as Radio TLC, Radiochemical purity, Gamma-counter, pH, LAL Test, Micro bacteria test, showed in same level with domestic [$^{18}F$]FDG Auto-Synthetic modules. Therefore, if some features were improved by considering the components life time and appearance, commercial sales can be expected because of low price and easy maintenance compared with foreign products.

• Journal of Information Display
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• 제2권3호
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• pp.48-53
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• 2001

Carbon nanotube emitters, prepared by screen printing, have demonstrated a great potential towards low-cost, largearea field emission displays. Carbon nanotube paste, essential to the screen printing technology, was formulated to exhibit low threshold electric fields as well as an emission uniformity over a large area. Two different types of triode structures, normal gate and undergate, have been investigated, leading us to the optimal structure designing. These carbon nanotube FEDs demonstrated color separation and high brightness over 300 $cd/m^2$ at a video-speed operation of moving images. Our recent developments are discussed in details.

• Environmental Engineering Research
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• 제15권3호
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• pp.141-147
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• 2010

The objective of this study was to assess the biofouling characteristics of the Bacillus biofilm formed on reverse osmosis (RO) membranes. For the study, a sporogenic Bacillus sp. was isolated from the seawater intake to a RO process, with two distinct sets of experiments performed to grow the Bacillus biofilm on the RO membrane using a lab-scale crossflow membrane test unit. Two operational feds were used, 9 L sterile-filtered seawater and 109 Bacillus cells, with flow rates of 1 L/min, and a constant 800 psi-pressure and pH 7.6. From the results, the membrane with more fouling, in which the observed permeate flux decreased to 33% of its initial value, showed about 10 and 100 times greater extracellular polymeric substances and spoOA genes expressions, respectively, than the those of the less fouled membrane (flux declined to 20% of its initial value). Interestingly; however, the number of culturable Bacillus sp. in the more fouled membrane was about 10 times less than that of the less fouled membrane. This indicated that while the number of Bacillus had less relevance with respect to the extent of biofouling, the activation of the genes of interest, which is initiative of biofilm development, had a more positive effect on biofouling than the mass of an individual Bacillus bacterium.

• 한국양식학회지
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• 제13권3호
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• pp.231-238
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• 2000

시판되는 넙치용 부상사료에 한방사료 첨가제인 어보산을 농도별 (0, 0.6및 1.2%)로 첨가한 후, 넙치의 성장, 사료효율, 비만도 및 혈액성분에 미치는 효과를 비교한 결과, 체중의 성장은 실험 8주 후부터 대조군과 첨가군간에서 유의한 차이가 나기 시작하여, 실험종료시 첨가군들이 대조군에 비해 7.8~9.1% 더 증가하였다 (P<0.05). 실험 전 기간을 통해 어보산 첨가군들의 일일성장률은 대조군보다 5.9~7.1% 더 좋은 결과를 보였고, 첨가군들의 사료효율도 대조군보다 13.2-14.2% 더 향상됨을 보였으며, 실험종료시 비만도도 첨가군들이 대조군에 비해 3.2~3.5% 정도의 유의한 증가를 보였다 (P<0.05). 특히 어보산 첨가군들 간의 성장 결과에서는 서로 유의한 차이가 나지 않음으로써, 어보산의 넙치 부상사료에 대한 적정 첨가농도는 0.6%로 판명되었다. 어보산 첨가농도별 넙치용 부상 사료로 사육한 넙치의 혈액성상을 분석한 결과, 각 실험군간 유의적 인 차이가 관찰되지 않았으나 (P>0.05), 혈청성분은 대조군과 어보산 첨가군들간 뚜렷한 차이를 보였는데, 어보산 첨가군들이 대조군에 비해 total protein과 glucose에서 높았고, total cholesterol, GOT와 GPT에서 낮은 값을 보였다 (P<0.05). 특히 혈청 GOT와 GPT에 있어 어보산 첨가군들은 대조군에 비해 매우 낮은 값을 보였다(P<0.05).

• 조명전기설비학회논문지
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• 제24권2호
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• pp.101-105
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• 2010

본 논문은 수열합성법에 의해 합성된 ZnO 나노와이어의 전계방출 특성을 연구하였다. ZnO 나노와이어는 핫플레이트 위에서 90[$^{\circ}C$]의 온도로 Au 박막위에서 합성되었으며, ZnO 나노와이어의 팁을 형성하기 위한 캡핑 재료로 SDS(Sodium Dodecyl Sulfate)를 0.05~0.3[wt%] 용액에 혼합하였다. 2시간동안 수열합성후 체인 형태의 ZnO 나노와이어가 성장되었다. 고순도의 ZnO 나노와이어는 울자이트(Wurzite) 구조의 팁 형태를 보였으며, ZnO 나노와이어의 전계방출 특성은 고진공 챔버에서 측정하였고, 나노와이어의 턴-온 전계는 0.1[${\mu}A/cm^2$]의 전류밀도에서 4.1V/${\mu}m$]를 나타내었다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.473-477
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• 2007

The development of advanced Insulated Gate Bipolar Transistor(IGBT)has enabled high-frequency switching operation and has improved the performance of PWM inverters for motor drive. However, the high rate of dv/dt of IGBT has adverse effects on motor insulation stress. In many motor drive applications, the inverter and motor are separated and it requires long motor feds. The long cable contributes high frequency ringing at the motor terminal and it results in hight surge voltage which stresses the motor insulation. The inverter output filter and RDC snubber are conventional method which can reduce the surge voltage. In this paper, we propose the new low loss snubber to reduce the motor terminal surge voltage. The snubber consists of the series connection of charging/discharging capacitor and the voltage-clamped capacitor. At IGBT turn-off, the snubber starts to operate when the IGBT voltage reaches the voltage-clamped level. Since dv/dt is decreased by snubber operating, the peak level of the surge voltage can be reduced. Also the snubber operates at the IGBT voltage above the voltage-clamped level, the snubber loss is largely reduced comparing with RDC snubber. The proposed snubber enables to reduce the motor terminal surge voltage with low loss.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.1038-1041
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• 2003

In the paper, we investigated silicon surface microstructures formed by reactive ion etching in hollow cathode system. Wet anisotropic chemical etching technique use to form random pyramidal structure on <100> silicon wafers usually is not effective in texturing of low-cost multicrystalline silicon wafers because of random orientation nature, but High density hollow cathode plasma system illustrates high deposition rate, better film crystal structure, improved etching characteristics. The etched silicon surface is covered by columnar microstructures with diameters form 50 to 100nm and depth of about 500nm. We used $SF_{6}$ and $O_{2}$ gases in HCP dry etch process. This paper demonstrates very high plasma density of $2{\times}10^{12}$ $cm^{-3}$ at a discharge current of 20 mA. Silicon etch rate of 1.3 ${\mu}s/min$. was achieved with $SF_{6}/O_{2}$ plasma conditions of total gas pressure=50 mTorr, gas flow rate=40 sccm, and rf power=200 W. Our experimental results can be used in various display systems such as thin film growth and etching for TFT-LCDs, emitter tip formations for FEDs, and bright plasma discharge for PDP applications. In this paper we directed our study to the silicon etching properties such as high etching rate, large area uniformity, low power with the high density plasma.

• 한국표면공학회지
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• 제38권4호
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• pp.163-166
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• 2005

Carbon nanotube-copper composite structures were fabricated using composite plating method and their field emission characteristics were investigated. Multi-walled carbon nanotubes (MWNTs) synthesized by chemical vapor deposition were used in the present study. It was revealed that turn-on field was about $3.0\;V/{\mu}m$ with the current density of $0.1\;{\mu}A/cm^2.$ We observed relatively uniform emission characteristics as well as stable emission current Carbon nanotube-copper composite plating method is efficient and it has no intrinsic limit on the deposition area. Moreover, it gives strong adhesion between emitters and an electrode. Therefore, we recommend that carbon nanotube-copper composite plating method can be applied to fabricate electron field emitters for large area FEDs and large area vacuum lighting sources.