• 한국전기전자재료학회논문지
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• 제22권9호
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• pp.728-731
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• 2009

We report numerical simulations to investigate of the dependendce of the on/off current ratio and channel charge distributions in silicon nanowire (SiNW) field-effect transistors (FETs) on the channel width and thicknesses. In order to investigate the transport behavior in devices with different channel geometries, we have performed detailed two-dimensional simulations of SiNWFETs and control FETs with a fixed channel length L of $10\;{\mu}m$, but varying the channel width W from 5 nm to $5\;{\mu}m$, and thickness t from 10 nm to 30 nm. We have show that $Q_{ON}/Q_{OFF}$ drastically decreases (from $^{\sim}2.9{\times}10^4$ to $^{\sim}9.8{\times}10^3$) as the channel thickness increases (from 10 nm to 30 nm). As a result of the simulation using a quantum model, even higher charge density in the bottom of SiNW channel was observed then in the bottom of control channel.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.139-142
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• 2000

Influence of frequency and duty ratio on electro-optical characteristics are experimentally investigated in surface AC plasma display panels(AC-PDPs) by using the VDS(Versitile Driving Simulator)., in which electrode gap and width are 100 ${\mu}m$ and 260 ${\mu}m$, respectively. The filling gas is Ne-Xe gas mixture, and total pressure 400 Torr. It is found that the response time gets to be fast from 450 ns to 150 ns as pulse-off time of the sustain pulse decreases from 2 ${\mu}s$ to 0.2 ${\mu}s$. Also it is found that the IR(Infra Red) intensity and the luminous decreases as pulse-off time of the sustain pulse increases from 0.2 ${\mu}s$ to 2 ${\mu}s$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1336_1337
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• 2009

본 논문에서는 유기 박막 트랜지스터의 전극을 잉크젯 프린팅과 스크린 프린팅 방법을 이용하여 유기 박막 트랜지스터를 제작하였다. 전극으로 PEDOT:PSS와 Ag 잉크를 사용하였고, 게이트 절연막으로 polymethyl methacrylate (PMMA)와 poly(4-vinylphenol) (PVP)를 사용하였다. 유기물 활성층으로 pentacene을 진공 증착하였다. 잉크젯 프린팅 방법을 이용하여 제작한 유기 박막 트랜지스터는 전계이동도 (${\mu}_{FET}$) $0.068\;cm^2$/Vs, 문턱전압 ($V_{th}$) -15 V, 전류 점멸비 ($I_{on}/I_{off}$ current ratio) >$10^4$의 전기적 특성을 보였고, 스크린 인쇄 방법을 이용하여 제작한 유기 박막 트랜지스터는 전계이동도 (${\mu}_{FET}$) $0.016\;cm^2$/Vs, 문턱전압 ($V_{th}$) 6 V, 전류 점멸비 ($I_{on}/I_{off}$ current ratio) >$10^4$의 전기적 특성을 보였다. 이를 통하여 프린팅 방법을 이용한 유기 박막 트랜지스터 단일 소자 및 유기 전자 회로 제작의 가능성을 확인 하였다.

• 대한기계학회논문집
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• 제17권6호
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• pp.1423-1430
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• 1993

본 연구에서는 레이저를 사용한 부재의 충돌속도 계측 실험을 통하여 기존 연구자들의 연구 결과를 비교하고, 이 결과를 바탕으로 보다 간단하고 유용한 실험식 을 제안하고자 한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.164.2-164.2
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• 2014

In order to combine advantages of ZnO thin film transistors (TFTs) with a high on-off ratio and graphene TFTs with extremely high carrier mobility, we present a facile methodology for fabricating ZnO thin film/graphene hybrid two-dimensional TFTs. Hybrid TFTs exhibited ambipolar behavior, an outstanding electron mobility of $329.7{\pm}16.9cm^2/V{\cdot}s$, and a high on-off ratio of $10^5$. The ambipolar behavior of the ZnO/graphene hybrid TFT with high electron mobility could be due to the superimposed density of states involving the donor states in the bandgap of ZnO thin films and the linear dispersion of monolayer graphene. We further established an applicable circuit model for understanding the improvement in carrier mobility of ZnO/graphene hybrid TFTs.

• Childhood Kidney Diseases
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• 제25권2호
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• pp.78-83
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• 2021

Background: Uric acid levels in urine are measured using urine specimens 24 hours or by uric acid glomerular filtration rate (UAGFR) with spot urine, which additionally requires a blood sample. This study aimed to investigate whether urinary uric acid creatinine ratio (UUACr) obtained by spot urine alone could be recognized as a substitute for UAGFR value, and hyperuricosuria can be screened by UUACr. UUACr is known to vary with age and regional differences. This study focused on the reference value of each value in Korean young populations. Method: We enrolled Korean subjects 1-20 years with normal kidney function, from a single hospital, classified into 5 age groups, 1-5 years, 6-8 years, 9-12 years, 13-15 years, and 16-20 years. We checked spot urine uric acid, creatinine and serum uric acid, creatinine levels on the same day from February 2014 to December 2018. We measured the average of UAGFR and UUACr in each groups. The UUACr cut-off value of the upper 2 standard deviation (SD) of UAGFR were taken. Results: The upper 2 SD of UUACr (mg/mg) and UAGFR (mg/dL) were determined in all age groups. UUACr decreased with grown up (P=0.000), but UAGFR were not statistically different among the groups. UUACr and UAGFR were not significantly different by gender. UUACr and UAGFR were positively correlated; UUACr cut-off value of upper 2 SD UAGFR (0.54 mg/dL) was 0.65 mg/mg in total age. Conclusions: UUACr could potentially be used to screen for hyperuricosuria.

• 대한전자공학회논문지
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• 제23권6호
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• pp.807-813
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• 1986

Measurements of interface states in a MOS capacitor by DLTS system using wideband monophase lock-in amplifier are discussed. A new signal analysis method that takes into account the bias pulse width and the gate off width is presented to remove the errors in the measured parameters of interface states resulting from the traditional method which neglects the effect of those widths. Theoretical calculations are made for the parameters related to the rate window, signal to noise ratio, and the energy resolution. On the grounds of this discussion, interface states of the MOS capacitor on p-type substrate of (110) orentation are measured with the optimal gate-off width with respect to the S/N ratio and the energy resolution. The results are interface state density of the order of 10**10 (cm-\ulcornereV**-1) to 10**11 (cm-\ulcornereV**-1) in the energy range of Ev+0.15(dV) to Ev+0.5(eV), and constant capture cross section of the order of 10**-16 (cm\ulcorner.

• Journal of Chest Surgery
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• 제56권2호
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• pp.99-107
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• 2023

Background: The neutrophil-to-lymphocyte ratio (NLR) has been suggested as a novel predictive marker of cardiovascular disease. However, its prognostic role in patients under-going coronary artery bypass grafting (CABG) is unclear. This study aimed to determine the association between the preoperative NLR and early mortality in patients undergoing CABG. Methods: Cardiac surgery was performed in 2,504 patients at Seoul St. Mary's Hospital from January 2010 to December 2021. This study retrospectively reviewed 920 patients who underwent isolated CABG, excluding those for whom the preoperative NLR was unavailable. The primary endpoints were the 30- and 90-day mortality after isolated CABG. Risk factor analysis was performed using logistic regression analysis. Based on the optimal cut-off value of preoperative NLR on the receiver operating characteristic curve, high and low NLR groups were compared. Results: The 30- and 90-day mortality rates were 3.8% (n=35) and 7.0% (n=64), respectively. In the multivariable analysis, preoperative NLR was significantly associated with 30-day mortality (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.17-1.39; p<0.001) and 90-day mortality (OR, 1.17; 95% CI, 1.07-1.28; p<0.001). The optimal cut-off value of the preoperative NLR was 3.4. Compared to the low NLR group (<3.4), the high NLR group (≥3.4) showed higher 30- and 90-day mortality rates (1.4% vs. 12.1%, p<0.001; 2.8% vs. 21.3%, p<0.001, respectively). Conclusion: Preoperative NLR was strongly associated with early mortality after isolated CABG, especially in patients with a high preoperative NLR (≥3.4). Further studies with larger cohorts are necessary to validate these results.

• 한국작물학회지
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• 제37권1호
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• pp.37-44
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• 1992

벼 콤바인 수확답에서 탈립된 종자의 월동중 활성검정 및 품종별 탈립량에 따른 이형주 발생정도와 양상을 검토, 벼 종자 순도유지에 관한 기초자료로 활용코저 하였던바 아래와 같은 결과를 얻었다. 1. 탈립종자의 시기별 발아율은 일반형, 통일형 모두 경과시기가 길어질수록 낮아지는 경향이었으며, 발아세의 경시적 변화도 같은 경향을 보였다. 2. 조사시기에 따른 종자 단백질의 전기영동적 차이에 있어서 팔공벼, 삼강벼 공히 단백질 Band에 농ㆍ담의 차이가 있었다. 3. 생태형별 이형주 발생율은 일반형 품종이 통일형 품종에 비하여 이형주는 대비품종에 비해 초장, 주당경수, 엽장, 절간장, 수장 및 수당립수 등의 형질이 저하되는 경향이었다. 또한 1차 지경보다는 2차지경에서 저하율이 컸으며 수당 영화수에 대한 상관정도는 2차지경이 높았다. 4. 이형주 종자의 발아능력은 대비품종에 비해 대차가 없었고 종자수량에 있어서 일반형 품종이 평균 5.1kg /10a, 통일형 품종이 평균 0.9kg /10a 였으며, 생태형별 대비품종에 대한 혼입비율은 일반형 품종이 0.7%, 통일형 품종이 0.1% 정도였다.

• Transactions on Electrical and Electronic Materials
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• 제12권2호
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• pp.43-50
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• 2011

Carbon-nanotube metal oxide semiconductor field effect transistor (CN-MOSFET) is a promising future device candidate. The electrical characteristics of 16 nm N-type CN-MOSFETs are explored in this paper. The optimum N-type CN-MOSFET device profiles with different number of tubes are identified for achieving the highest on-state to off-state current ratio ($I_{on}/I_{off}$). The influence of substrate voltage on device performance is also investigated in this paper. Tradeoffs between subthreshold leakage current and overall switch quality are evaluated with different substrate bias voltages. Technology development guidelines for achieving high-speed, low-leakage, area efficient, and manufacturable carbon nanotube integrated circuits are provided.