• 한국전기전자재료학회논문지
• /
• 제21권4호
• /
• pp.296-299
• /
• 2008

The effects of radio frequency (RF) source power for decoupled plasma nitridation (DPN) process on the electrical properties and Fowler-Nordheim (FN) stress immunity of the oxynitride gate dielectrics for deep nano-technology devices has been investigated. With increase of RF source power, the threshold voltage (Vth) of a NMOS transistor(TR) decreased and that of a PMOS transistor increased, indicating that the increase of nitrogen incorporation in the oxynitride layer due to higher RF source power induced more positive fixed charges. The improved off-current characteristics and wafer uniformity of PMOS Vth were observed with higher RF source power. FN stress immunity, however, has been degenerated with increasing RF source power, which was attributed to the increased trap sites in the oxynitride layer. With the experimental results, we could optimize the DPN process minimizing the power consumption of a device and satisfying the gate oxide reliability.

• 한국방사선학회논문지
• /
• 제6권4호
• /
• pp.275-279
• /
• 2012

16MD CT(n=93) and dual source CT(n=100)를 이용해 촬영된 심장 CT 중 그 결과 협착으로 진단되어 심장영화 촬영을 시행한 환자를 대상으로 심장영화 촬영과의 협착 유무에 대한 비교를 하였다. 그 결과 16MDCT의 경우 가장 높은 민감도, 특이도, 양성예측도, 음성예측도는 LAD(73.5%), RCA(74.5%), LAD(66.7%), LCX(75%), LCX(67.7%)로 나타났고, 16Slice MDCT에서 각 관상동맥 혈관별 정확도는 평균67%로 다소 떨어지는 것으로 나타났고, Somatom Definition dual source CT의 경우 평균 정확도 84%로 16Slice MDCT보다는 17%더 높은 정확도를 나타내었다. 관상동맥영역별(segaments) 구분에서는 16Slice MDCT와 Somatom Definition 모두 근위부(proximal)보다는 원위부로 갈수록 더 높은 정확도를 나타내었다. 하지만 그 결과 값이 10% 오차 범위 내에 있어 명확한 차이라 보기는 힘들 것 이다. 또한 Dual source CT의 경우 역시 관상동맥 영역별 구분에서 큰 차이를 보이지 않았다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2007년도 하계종합학술대회 논문집
• /
• pp.127-128
• /
• 2007

A dual band LNA is designed to set input matching and noise matching with source transmission feedback for wireless LAN applications. Some design techniques for the transmission line feedback of the dual band LNA have been developed with input and output design equations. The measured results shows close agreement with the simulated performance.

• Structural Engineering and Mechanics
• /
• 제56권3호
• /
• pp.341-354
• /
• 2015

The dual-phase lag heat transfer model is employed to study the problem of isotropic generalized thermoelastic medium with internal heat source. The normal mode analysis is used to obtain the exact expressions for displacement components, force stress and temperature distribution. The variations of the considered variables through the horizontal distance are illustrated graphically. The results are discussed and depicted graphically.

• 한국전자파학회논문지
• /
• 제15권2호
• /
• pp.140-144
• /
• 2004

직렬 공진형 공통 소스 접지 트랜지스터 쌍은 선택형 이중 밴드 LNA에 가장 널리 사용되는 구조이다. 본 논문은 이러한 선택형 이중밴드 저잡음 증폭기를 동시에 서로 다른 주파수에서 구동하였을 때 나타나는 잡음지수의 악화 정도를 해석하고, 0.18$\mu\textrm{m}$ CMOS 공정으로 구현한 LNA의 실험 결과와 비교한다. 아울러, 잡음 해석을 통해 다른 밴드 LNA로부터 발생하는 트랜지스터의 채널 잡음과 전원 잡음의 기여도를 분석하고, 동시형 LNA로 사용하였을 때 잡음을 최소화하기 위한 정합구조를 제안한다.

• Journal of Welding and Joining
• /
• 제15권4호
• /
• pp.99-108
• /
• 1997

Analytical model for the temperature distribution and the cooling rate of weld in dual beam laser welding is presented for investigating the possibility of controling the cooling rate. The model is based on the solutions to the problem of heat flow due to the distributed and line heat sources for preheating and welding respectively in plates with finite thickness. The effects of beam power, beam distribution parameter, interbeam distance, and welding speed on the resulting temperature distribution and cooling rate are presented. The cooling rates of dual beam laser weld at the weld centerline under the investigated conditions are reduced to as one third of those of welds which were produced by single beam laser. And it appeared that the cooling rate of dual beam laser weld is strongly dependent on the process parameters of preheating laser beam power and welding speed.

• Korean Journal of Radiology
• /
• 제19권6호
• /
• pp.1031-1041
• /
• 2018

Objective: To compare image quality and radiation dose of high-pitch dual-source spiral cardiothoracic computed tomography (CT) between non-electrocardiography (ECG)-synchronized and prospectively ECG-triggered data acquisitions in young children with congenital heart disease. Materials and Methods: Eighty-six children (${\leq}3$ years) with congenital heart disease who underwent high-pitch dual-source spiral cardiothoracic CT were included in this retrospective study. They were divided into two groups (n = 43 for each; group 1 with non-ECG-synchronization and group 2 with prospective ECG triggering). Patient-related parameters, radiation dose, and image quality were compared between the two groups. Results: There were no significant differences in patient-related parameters including age, cross-sectional area, body density, and water-equivalent area between the two groups (p > 0.05). Regarding radiation dose parameters, only volume CT dose index values were significantly different between group 1 ($1.13{\pm}0.09mGy$) and group 2 ($1.07{\pm}0.12mGy$, p < 0.02). Among image quality parameters, significantly higher image noise ($3.8{\pm}0.7$ Hounsfield units [HU] vs. $3.3{\pm}0.6HU$, p < 0.001), significantly lower signal-to-noise ratio ($105.0{\pm}28.9$ vs. $134.1{\pm}44.4$, p = 0.001) and contrast-to-noise ratio ($84.5{\pm}27.2$ vs. $110.1{\pm}43.2$, p = 0.002), and significantly less diaphragm motion artifacts ($3.8{\pm}0.5$ vs. $3.7{\pm}0.4$, p < 0.04) were found in group 1 compared with group 2. Image quality grades of cardiac structures, coronary arteries, ascending aorta, pulmonary trunk, lung markings, and chest wall showed no significant difference between groups (p > 0.05). Conclusion: In high-pitch dual-source spiral pediatric cardiothoracic CT, additional ECG triggering does not substantially reduce motion artifacts in young children with congenital heart disease.

• 전자공학회논문지B
• /
• 제32B권6호
• /
• pp.899-908
• /
• 1995

In this paper, the probabilistic relations of dual morphological operations, such as dilation and erosion, closing and opening, and close- open and open-close, and the statistical properties for a continuous stationary lst order Gauss-Markov source are analyzed. The result is that the dual filters have symmetrical means and skews, and equal variances. Also, the statistics of morphological filters are very similar with those of input source, as correlation coefficient increases.

• Transactions on Electrical and Electronic Materials
• /
• 제16권5호
• /
• pp.254-259
• /
• 2015

This paper reports the optimized mixed-signal performance of a high-voltage (HV) laterally double-diffused metaloxide-semiconductor (LDMOS) field-effect transistor (FET) with a dual gate oxide (DGOX). The fabricated device is based on the split-gate FET concept. In addition, the gate oxide on the source-side channel is thicker than that on the drain-side channel. The experiment results showed that the electrical characteristics are strongly dependent on the source-side channel length with a thick gate oxide. The digital and analog performances according to the source-side channel length of the DGOX LDMOS device were examined for circuit applications. The HV DGOX device with various source-side channel lengths showed reduced by maximum 37% on-resistance (R_ON) and 50% drain conductance (g_ds). Therefore, the optimized mixed-signal performance of the HV DGOX device can be obtained when the source-side channel length with a thick gate oxide is shorter than half of the channel length.

• 대한전자공학회논문지TC
• /
• 제44권7호통권361호
• /
• pp.23-28
• /
• 2007

본 논문에서는 무선 랜용 이중대역 GaAs FET 저잡음 증폭기를 설계하기 위하여 인덕턴스 소스 피드백을 이용하고 입력 단에는 이중대역 LC 공진회로를 이용하였으며, 출력단에는 Cheyshev 필터의 임피던스 변환 회로를 이용하였다. 이중대역 증폭기의 입출력정합회로 설계에 필요한 기법 및 수식들을 유도하였으며 설계된 증폭기를 제작하여 측정한 결과 시뮬레이션 결과와 유사한 측정치를 얻을 수 있었다.