• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1508-1510
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• 1999

스퍼터 퇴적 $WO_3$ 박막에 대해 열처리에 따른 전기적특성 및 구조적특성을 각각 4탐침법 및 AFM 관측에 의해 조사해 보고, 또한 스퍼터링시의 산소가스 유량비에 따른 $WO_3$ 박막의 막질을 ESCA에 의해 평가하였다 실험 결과 열처리에 의해 $WO_3$ 박막 표면의 평균거칠기가 $2.45\AA$에서 $152\AA$으로 크게 증가함을 알 수 있었다 또한 스퍼터시 산소유량비에 따른 효과를 ESCA로 관측한 결과, 열처리전에는 주피크가 34eV에서 나타남에 비해 열처리 후에는 36eV전후에서 나타났다.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.149-149
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• 2011

아르곤 기체의 방사세기 또는 그 세기 비는 플라즈마 공정 진단에서 일반적으로 사용된다. 본 실험에서는 100 mTorr 압력 조건하의 유도결합 플라즈마(13.56 MHz)에서 E-H 모드 전이 영역, rf 바이어스(12.5 MHz) 전력 인가 및 N2 혼합 시 단순화한 충돌-방사 모델에 기초한 광방사 세기비 방법을 적용하여 플라즈마 변수를 진단하였다. 개발 프로그램 기반의 분광기를 사용하여 아르곤 기체의 특정 파장(750.4, 751.5 그리고 811.5 nm)들을 관측하였고, 동일한 조건하에서 정전 탐침법으을 이용하여 전자 에너지 분포함수의 변화도 측정 하였다. 맥스웰 전자 에너지 분포를 가정하는 일반적인 경우와 비교하여 볼 때 실제적인 전자 에너지 분포함수의 측정은 전자의 가열 메커니즘에 대한 상세한 정보를 제공함과 동시에 플라즈마 재흡수에 대한 보정을 가능하게 해준다. 광방사 세기비법에 의해 측정된 결과에 의하면, 750.4 nm/751.5 nm는 높은 에너지(>13.08 eV)의 전자들의 유효 전자온도에 대한 정보를 나타내는 반면 811.5 nm/750.4 nm는 아르곤 준안정 준위 밀도(1s5)에 대한 정보를 제공하게 된다. 수행된 실험 조건하에서, 측정된 준안정 준위 밀도는 E-H 모드 전이 영역에서 최대값을 나타내었고 바이어스 전압 및 N2 기체 혼합 비율이 증가함에 따라 감소하는 결과를 얻었다. 유효 전자온도의 경우 광방사 세기비법과 정전 탐침법 모두 같은 결과를 보여 주었는데, E-H 모드 전이 영역에서는 전자온도는 거의 일정하였고 바이어스 전압 및 N2 기체 혼합 비율이 증가함에 따라 전자온도는 증가하였다. 이러한 실험 결과는 방전 모드 전이, 바이어스 인가 그리고 혼합 기체 사용하는 공정 플라즈마를 이해하는데 있어 이들 변수의 진단이 중요한 요소임을 보여준다.

• Journal of the Korean Geotechnical Society
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• v.30 no.4
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• pp.93-99
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• 2014

Use of geothermal energy has been increased for its economical application and environmentally friendly utilization. Particularly, for energy piles, a spiral coil type ground heat exchanger (GHE) is more preferred than line type GHEs such as U and W shaped GHEs. A PHC energy pile with spiral coil type GHE was installed in an area of partially saturated dredged soil deposit, and a thermal response test (TRT) was conducted for 240 hours under a continuous operation condition. Besides, remolded soil samples from different layers were collected in the field, and soil specimens were reconstructed according to the field ground condition. Non-steady state probe methods were conducted in the lab, and ground thermal conductivity and thermal diffusivity were measured for the different soil layers. An equivalent ground thermal conductivity was calculated from the lab test results and it was compared with the field TRT result. The difference was less than 5%, which advocates the use of an equivalent ground thermal conductivity for the multi-layered ground. Furthermore, this paper also represents an equivalent ground thermal diffusivity evaluation method which is another very important design parameter.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.1
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• pp.21-25
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• 1999

The TiN, thin films were prepared on glass substrate by RF(radio-frequency) magnetron sputtering apparatus from a Ti target in a gaseous mixture of argon and nitrogen. In deposition, a RF power supply was used as a power source with a constant power of 240W, and the substrate was heated to $200^{\circ}C$. The films were obtained at nitogen flow rates in the range 3-9 sccm with a constant argon flow rate of 20 secm. For the films obtained, the sheet resistance and the chemical binding energy of the films was observed by four-point-probe method and x-ray photoelectron spectroscopy(XPS) depth profiling respectively. In addition, we investigated the relationship between the surface resistance and the chemical nature of the films.

• The Korean Journal of Mycology
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• v.31 no.3
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• pp.121-128
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• 2003

This study was carried out to identify the phylogenetic relationship of Phellinus species and to know its distribution by comparing the DNA sequences of internal transcribed spacer regions(ITS1 and IST2) and 5.8S ribosomal DNA (rDNA) repeat unit. The Phellinus species had their specific sequences in IST1 and 2 regions depending on suedes. The comparison of the ITS sequences of standard strains indicated that the sequences of ITS1 were more variable than those of ITS2. Nine strains of the commercial products of Phellinus species used in this study were identified as P. lintues, P. baumii, P. igniarius, and P. pini. Most of commercial species were P. pini and P. baumii, and P. gilvus was not found. Also, P. linteus was only found in form of mycelial culture rather than fruiting body. Moreover, the species-specific primers were designed based on ITS sequence data. Each species-specific primers were bound in P. lintues(ITSF-PL2R), P. baumii(PB1F-ITS4R), P. igniarius(IF1-IR3), P. pini(PF1-PR3), and P. gilvus(GF2-GR4), respectively. These primer sets would be useful fer the detection of specific-species among unidentified Phellinus species rapidly.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.124-124
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• 2017

Fe-Ni-Co 합금 박막(<$100{\mu}m$)을 황화물계 용액에서 전주공정으로 제조하였다. XRF로 측정한 박판의 평균 조성은 Fe-34 wt.% Ni-3 wt.% Co 이다. AFM으로 측정한 표면 조도는 35.2 nm 이다. 표면의 나노 경도는 평균 5.4 GPa 이었다. Oliver 모델을 적용한 구리 박막의 탄성하강강성도는 약 75 이었다. Alekhin 모델을 적용한 구리 박막의 마찰계수, 피로한계는 각각 0.134, 0.027 이었다. 유한요소법으로 평가한 Berkovich 형 나노압침선단의 하중분포를 이차원 선형 및 비선형 해석하면 1 [mN]의 정적하중을 가한 Fe-Ni-Co 박막은 약 576 [mN]로 예측되었다. 압침선단의 하중집중정도는 표면탐침현미경으로 관찰한 압흔의 변형정도와 유사한 경향을 보였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.139-141
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• 2005

이번 실험에서는 변방전형 교류 PDP에서의 3차원적인 전자온도와 이온밀도의 측정을 마이크로 랑뮈르 탐침법을 통해 실험적으로 연구하였다. 스테핑 모터에 연결된 마이크로 랑뮈르 탐침은 20um씩 움직이며 탐침에 인가하는 플러스와 마이너스의 직류전압을 통해 I-V곡선을 구할 수 있고 이를 통해서 전자온도와 플라스마 밀도를 구할 수 있다. Ne+Xe(4%) 200Torr의 혼합가스에서 전극의 테두리를 따라(X축) 전자온도 및 플라스마 밀도를 측정한 결과 중앙지점에서와 전극의 경계지역에서 이온밀도는 $7.69{\sim}11.1{\times}10^{11}cm^{-3}$ 까지 측정되었다. 또한 전자온도는 플라스마 밀도와 균형적인 관계에 있다는 것은 주목할 만하다. 전자온도는 전극 사이의 중심에서 가장 적게 1.3 ~ 3.15eV까지 측정되었다. Y축으로 측정했을 경우 이온 밀도와 전자온도는 전극 갭 중앙에서부터 약 80um 떨어진 지점에서 서로 교차하며 증가 및 감소였으며 이온밀도는 $8.3{\sim}11.1{\times}10^{11}cm^{-3}$로 측정되었고 전자온도는 이와 균형적인 관계를 가지고 1.2~1.6eV로 측정되었다. 또한 이러한 특성은 AC PDP 에서 나타나는 줄무늬 현상과 관련이 있는 것으로 보인다. Z축으로 측정했을 경우 약 125um높이에서 가장 높게 측정되었으며 $1.1{\times}10^{12}cm^{-3}$정도로 측정되었다.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.4 s.33
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• pp.23-27
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• 2004

The $Al_xTa_{1-x} (x=0.0{\~}1.0)$ alloy thin films were deposited by RF-magnetron sputtering system, and the crystal quality, surface morphology, and electrical properties were examined using XRD, AFM, 4-point probe techniques in this study. The thin films were grown according to the alloy compositions first, and the effects of film thickness and mask patterns were investigated afterwards. Also, the heating characteristics were examined by heat controller. The obtained results showed that the high electrical resistivity was obtained for Al content $x=6.63at\%$, and the even higher resistivity was accomplished for the samples with smaller thickness and narrower width. The heating temperature demonstrated the identical trend to the electrical properties, and the highest heating temperature ($400^{\circ}C$) and output power ($12.6W/cm^2$) were obtained for the sample with Al content $x=6.63\%$, film thickness d=500 nm, film width w=1.5 mm.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.529-538
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• 2002

There is no adverse opinion on the anticariogenic effect of fluoride, so glass ionomer restoration which release the fluoride is recommended fer child patient. To study the anticariogenic effect of initial carious lesion of fluoride released from adjacent glass ionomer restoration, the in situ model was constructed. A microhardness test, polarized scope investigation and electron probe microanalysis was done for analyzing the distribution of fluoride which was precipitated from glass ionomer restoration to the enamel caries lesion. Fuji IX, the conventional glass ionomer, was used for experimental group and Z-100, composite resin that fluoride was not contained, was used for control group. On the microhardness test, the remineralization was accelerated by fluoride. And on the polarized investigation, the size of caries lesion was reduced in the oral cavity and that phenomenon was accelerated by fluoride, too. Electron probe microanalysis shows that the remineralization was accelerated by fluoride and the fluoride concentration on subsurface area was increased. It maybe that the subsurface area was critical to anticariogenic effect. In summary of these result, initial caries lesion can be remineralized in the oral cavity and that phenomenon can be accelerated by fluoride. The subsurface area of caries lesion was a major part of defense to cariogenic invasion and to conserve the subsurface area, the surface of lesion body have to conserved.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.304-309
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• 2012

Size verification of small and large bubbles in a bubble column was investigated by employing the dynamic gas disengagement (DGD) method and dual electrical resistivity probe (DRP) method, simultancously. The holdups of large and small bubbles in the bubble column in a given operating condition were obtained by means of the DGD method by measuring the pressure drop variation in the column with a variation of time after stopping the gas input into the column. The size and frequency of bubbles were measured by the DRP method in the same operating condition, from which the bubble holdup of each range of size was obtained. The verification of size in determining the large or small bubbles was decided by comparing the holdups of large or small bubbles measured by the DGD method with that measured by the DRP method. Filtered compressed air and tap water were used as a gas and a continuous liquid medium. The diameter and height of the bubble column were 0.102 m and 1.5 m, respectively. The demarcation size between the large and the small bubbles in the bubble column was 4.0~5.0 mm; the demarcation size was about 5.0 mm when the gas velocity was in the relatively low range, but about 4.0 mm when the gas velocity was in the relatively high range, within this experimental conditions.