• 한국전기전자재료학회논문지
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• 제23권2호
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• pp.89-92
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• 2010

A bolometer sensor used in an infrared thermal imaging system has many advantages on the process because it does not need a separate cooling system and its manufacturing is easy. However the sensitivity of the bolometer is low and the fixed pattern noise(FPN) is large, because the bolometer sensor is made by micro electro mechanical systems (MEMS). These problems can be fixed-by using the high performance readout integrated circuit(ROIC) with noise reduction techniques. In this paper, we propose differential delta sampling circuit to remove the mismatch noise of ROIC itself, the FPN of the bolometer. And for reduction of FPN noise, the reference signal compensation circuit which compensate the reference signal by using on-resistance of MOS transistor was proposed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기설비전문위원
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• pp.91-93
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• 2004

This study presents recent trends on the on-line monitoring and diagnostic systems for oil-immersed transformers. Specially, our system on Yeo Su thermal power plant is introduced for high sensitivity and accuracy of ours. It is combined with communication networks to provide an on-line remote monitoring system. Several alarm criteria are formulated to enable a superimposed monitoring system to perform decisive action. The reasons for monitoring the condition and maintaining the health of electrical apparatus were discussed. The experience at the fields and the criteria for the judgment are also discussed in detail.

• 센서학회지
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• 제18권3호
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• pp.222-225
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• 2009

This paper describes the fabrication and characteristics of Schottky micro hydrogen sensors for high temperatures by using polycrystalline(poly) 3C-SiC thin films grown on Si substrates with thermal oxide layer using APCVD. Pd/poly 3C-SiC Schottky diodes were made and evaluated by I-V and C-V measurements. Electric current density and barrier height voltage were $2{\times}10^{-3}A/cm^2$ and 0.58 eV, respectively. These devices could operate stably at about 400 $^{\circ}$. The characteristics of implemented sensors have been investigated in terms of sensitivity, linearity of response, response rate, and response time. Therefore, from these results, Pd/poly 3C-SiC Schottky devices have very high potential for high temperature $H_2$ sensor applications.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.113-113
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• 2015

본 연구에서는 thermal evaporation법을 이용하여 제작한 CdTe 후막의 미세구조, 전기적 특성 및 X-선 조사에 따른 특성을 비교분석하였다. 기판온도를 $370{\sim}450^{\circ}C$로 변화시키며 증착하였으며, CdCl2 첨가에 따른 미세구조 변화를 관찰하였다. CdTe 막의 상 하부에 전극을 형성하여 I-V 특성을 평가하고, 실제 X-ray를 샘플에 조사하여 sensitivity를 측정하였다. 박막형성 초기에는 기판온도가 증가함에 따라 grain size가 증가하였지만, grain uniformity는 감소하였다. X-ray 특성향상을 위해서는 grain size와 uniformity 모두 중요한 인자이기 때문에 uniformity 향상을 위해 Cl을 첨가하였다. 미량의 Cl 첨가에서는 큰 변화를 보이지 않았지만 더 많은 양의 Cl 첨가 시, grain size 와 uniformity 모두 증가되는 것을 확인하였으며, 그에 따라 I-V, X-ray 조사 특성 모두 개선되는 것을 확인할 수 있었다.

• Nuclear Engineering and Technology
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• 제50권6호
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• pp.981-988
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• 2018

An experiment was performed for the OECD/NEA ROSA-2 Project with the large-scale test facility (LSTF), which simulated a steam generator tube rupture (SGTR) accident due to a double-ended guillotine break of one of steam generator (SG) U-tubes with operator recovery actions in a pressurized water reactor. The relief valve of broken SG opened three times after the start of intact SG secondary-side depressurization as the recovery action. Multi-dimensional phenomena specific to the SGTR accident appeared such as significant thermal stratification in a cold leg in broken loop especially during the operation of high-pressure injection (HPI) system. The RELAP5/MOD3.3 code overpredicted the broken SG secondary-side pressure after the start of the intact SG secondary-side depressurization, and failed to calculate the cold leg fluid temperature in broken loop. The combination of the number of the ruptured SG tubes and the HPI system operation difference was found to significantly affect the primary and SG secondary-side pressures through sensitivity analyses with the RELAP5 code.

• Current Optics and Photonics
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• 제5권2호
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• pp.121-128
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• 2021

We propose a novel, tiny optical receiver engine utilizing an all-in-one package based on embedded optics technology. The package's best transmission S21 and reflection S22 opto-electric (OE) bandwidths are 49.8 GHz and 34.9 GHz, respectively, and the reflectance of the optical engine is below -31.7 dB for all channels. The engine satisfies the MIL-STD-883G standard for reliability tests, such as mechanical and thermal shock, and vibration resistance. The sensitivity after 10 km single-mode fiber (SMF) transmission is below -8 dBm. The optical receiver engine is cost-competitive and applicable for 400G coarse wavelength division multiplexing 4 (CWDM4) 10 km optical transceivers.

• 대한치과의사협회지
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• 제57권7호
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• pp.403-411
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• 2019

A cracked tooth is defined as an incomplete fracture initiated from the crown and extending subgingivally and usually directed mesiodistally. Cracked teeth were most frequently involved in mandibular and maxillary molars at the age of 50s. Cracks occurred mainly in nonbonded restorations such as gold and amalgam, and majority of cracks were found in intact teeth. A pulpal and periapical diagnosis is dependent on the extent of the crack and duration of the symptom. The pulp of a cracked tooth might become inflamed because of microleakage, which induces thermal sensitivity. Once the crack has extended and exposed the pulp, severe pulp and periapical pathosis will likely be present. In addition, the extended crack can cause a bony dehiscence with a resulting narrow and deep periodontal pocket. Therefore, early diagnosis of the cracked tooth and proper treatment planning are important for clinician.

• Journal of Ceramic Processing Research
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• 제20권4호
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• pp.388-394
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• 2019

In this study, high-purity single-walled carbon nanotubes (SWCNTs) were prepared by removing the unreacted metal constituents and amorphous carbon impurities using a post-annealing process. Unlike conventional thermal processing techniques, this technique involved different gas atmospheres for efficient removal of impurities. A heat treatment was conducted in the presence of chlorine, oxygen, and chlorine + oxygen gases. The nanotubes demonstrated the best characteristics, when the heat treatment was conducted in the presence of a mixture of chlorine and oxygen gases. The scanning electron microscopy, transmission electron microscopy, ultraviolet absorbance, and sheet resistance measurements showed that the heat treatment process efficiently removed the unreacted metal and amorphous carbon impurities from the as-synthesized SWCNTs. The high-purity SWCNTs exhibited improved electrical conductivities. Such high-purity SWCNTs can be used in various carbon composites for improving the sensitivity of gas sensors.

• 대한전자공학회논문지
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• 제23권6호
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• pp.795-800
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• 1986

High value sheet resistance (Rs, 350\ulcorner/ -80K\ulcorner/) born implanted polysilicon resistors were fabricated under process conditions compatible with bipolar integrated circuits fabrications. This paper includes studies of sensitivity of Rs to doping concentration, the effect of thermal annealing temperature on Rs, temperature coefficient of resistance (TCR), the effect of polysilicon thickness on Rs and the Rs variation within a run and between runs.

• 방사성폐기물학회지
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• 제6권2호
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• pp.119-128
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• 2008

본 연구에서는 사용후핵연료 회수성과 처분밀도를 향상시킨 새로운 CANDU 사용후핵 연료처분시스템의 열해석을 수행하였다. 제안된 CANDU 사용후핵연료 처분방식 에서는 사용후핵연료의 회수성을 향상시키기 위해 일정 기간 동안 터널에 자연대류를 이용하여 저장하며, 처분밀도 향상을 위해 개선된 CAHDU 사용후핵연료 처분용기를 이용하고 있다. 제안된 CANDU 사용후핵연료 처분방식의 열적 안전성을 검토하고자 ANSYS 10.0 CFX 코드를 사용하여 시스템 전체의 정상상태 열 해석을 2단계로 나누어 수행하였다. 1단계에서는 터널간격이 처분터널 내부 온도에 미치는 영향을 분석하기 위해 터널 간격에 따른 처분터널 내벽온도 변화를 계산하였다. 계산 결과 99%의 붕괴열이 대류에 의해 냉각되는 것을 확인하였고, 이로 인해 터널 간격은 처분터널 내부 온도에 거의 영향을 주지 않았다. 2단계 계산에서는 터널간격 60 m에서 환기 설비를 고려한 처분터널의 내벽온도를 계산하였고, 이 결과는 처분터널 내부 처분용기의 표면온도를 구하기 위해 사용되었다. 계산결과, 처분용기의 표면온도는 최대 $119^{\circ}C$, 평균 $79.9^{\circ}C$로 계산되었다. 처분용기 최대온도에 따른 처분용기 내부 바스켓 피복재 최대온도는 $140.9^{\circ}C$로 계산하였으며, 이는 피복재 열적 특성을 고려하였을 때 충분한 열적 안전성을 가지고 있다고 판단되었다.