• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2008년도 하계종합학술대회
• /
• pp.559-560
• /
• 2008

In this paper, I proposed 10bits 40MS/s Pipelined A/D converter. The op-amps for SHA and MDAC designed folded-cascode amplifier with gain-booster. And the MOS transistors with a low threshold voltage are employed to low on-resistor and parasitic capacitance. The power dissipation is 119㎽ at 1.2V and 40MS/s

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2003년도 춘계학술대회 논문집
• /
• pp.313-318
• /
• 2003

The development of new materials with light weight and high strength has become vital to the machinery, aircraft and auto industries. However, there are a lot of problems with developing such materials that require expensive tools, and a great deal of time and effort. Therefore, the improvement of fatigue strength and fatigue life are mainly focused on by adopting residual stress(in this thesis). The compressive residual stress was imposed on the surface according to each shot velocity(57, 70, 83, 96 m/sec) based on Shot-peening, which is the method of improving fatigue lift: and strength. By using the methods mentioned above, I arrived at the following conclusions 1. The fatigue crack growth rate(da/dN) of the Shot-peened material was lower than that of the Un-peened material. And in stage I, ${\Delta}K_{th}$, the threshold stress intensity factor, of the shot-peen processed material is high in critical parts unlike the Un-peened material. Also m, fatigue crack growth exponent and number of cycle of the Shot-peened material was higher than that of the Un-peened material. That is concluded from effect of da/dN. 2. Fatigue life shows more improvement in the Shot-peened material than in the Un-peened material. And compressive residual stress of surface on the Shot-peen processed operate resistance force of fatigue crack propagation.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2007년도 추계학술대회 논문집
• /
• pp.171-172
• /
• 2007

We fabricated the metal-ferroelectric-insulator-semiconductor filed-effect transistors (MFIS-FETs) using the $(Bi,La)_4Ti_3O_{12}\;and\;LaZrO_x$ thin films. The $LaZrO_x$ thin film had a equivalent oxide thickness (EOT) value of 8.7 nm. From the capacitance-voltage (C-V) measurements for an Au/$(Bi,La)_4Ti_3O_{12}/LaZrO_x$/Si MFIS capacitor, a hysteric shift with a clockwise direction was observed and the memory window width was about 1.4 V for the bias voltage sweeping of ${\pm}9V$. From drain current-gate voltage $(I_D-V_G)$ characteristics of the fabricated Fe-FETs, the obtained threshold voltage shift (memory window) was about 1 V due to ferroelectric nature of BLT film. The drain current-drain voltage $(I_D-V_D)$ characteristics of the fabricated Fe-FETs showed typical n-channel FETs current-voltage characteristics.

• 한국정보통신학회논문지
• /
• 제19권12호
• /
• pp.2899-2904
• /
• 2015

3차원 순차적 집적회로에서 열에 의한 손상으로 생성되는 계면 포획 전하가 트랜지스터의 드레인 전류-게이트 전압 특성에 미치는 영향을 소개한다. 2차원 소자 시뮬레이터를 이용해서 산화막 층에 계면 포획 전자 분포를 추출한 결과를 설명한다. 이 계면 포획 전자분포를 고려한 3차원 순차적 집적회로에서 Inter Layer Dielectric (ILD)의 길이에 따른 하층 트랜지스터의 게이트 전압의 변화에 따라서 상층 트랜지스터의 문턱전압 $V_{th}$의 변화량에 대해서 소개한다. 상대적으로 더 늦은 공정인 상층 $HfO_2$층 보다 하층 $HfO_2$층과 양쪽 $SiO_2$층이 열에 의한 영향을 더 많이 받았다. 계면 포획 전하 밀도 분포를 사용하지 않았을 때 보다 사용 했을 때 $V_{th}$ 변화량이 더 적게 변하는 것을 확인 했다. 3차원 순차적 인버터에서 ILD의 길이가 50nm이하로 짧아질수록 점점 더 $V_{th}$ 변화량이 급격히 증가하였다.

• 한국해양공학회지
• /
• 제16권5호
• /
• pp.73-79
• /
• 2002

In this paper, the effect of the compressive residual stresses was obtained at the test conditions of the higher temperature than the ambient temperature. The examination was performed with the CT specimen result of the material(JISG SUP9) which is being commonly used for the marine engine parts and the ocean structures. As a result, the test conditions at the higher temperature were acquired considering the peak values of the compressive residual stresses of the specimens and the effect on the fatigue crack propagation speed da／dN in stage II and the threshold stress intensity factor range Δth in stage I. Also the material constant C and the fatigue crack propagation index m in the formula of Paris Law da／dN＝C (ΔK)$^{m}$ were suggested to estimate the dependence on the test temperature.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1999년도 추계종합학술대회 논문집
• /
• pp.191-194
• /
• 1999

Switching behaviour of the ferroelectric thin film and device characteristics of the MFSFET (Metal-Ferroelectric-Semiconductor FET) are simulated with taking into account the accumulation of oxygen vacancies near interface between the ferroelectric thin film and the bottom electrode caused by the progress of fatigue. We show net switching current decreases due fatigue in the switching model. It indicates that oxygen vacancy strongly suppresses polarization reversal. The difference of saturation drain current of the device before fatigue is shown by the dual threshold voltages in I$_{D}$-V$_{D}$ curve as 6㎃/$\textrm{cm}^2$ and decreases as much as 50% after fatigue. Our simulation model is expected to play an important role in estimation of the behavior of MFSFET device with various ferroelectric thin films.lms.

• 한국임상수의학회지
• /
• 제15권2호
• /
• pp.410-416
• /
• 1998

These experiments were designed to evaluate the possibility of brain-stem auditory evoked responses(BAER) as a diagnostic tool for deafness in dogs. The BAER was recorded from three different groups of dogs; the normal dogs,'dog with otitis externa and dogs with unilateral destruction of cochlear. BAER of the normal dogs was consisted of distinct five peaks(I, II, III-IV, V). Furthermore, the clear shapes of waveform were observed at 85 dB. The latency of BAER was increased with reducing the intensity of sound-stimulus. The highest threshold of BAER was measured at 2 KHz with 10-30 dB. Dog with otitis externs demonstrated unclear shapes of BAER compared to the that of normal dogs. In the dogs with unilateral destruction of cochlear, the flat and indistinct waveform of BAER was recorded from the cochlear destroyed ear while that of BAER from normal side of ears did not show any differences from the normal BAER. These results indicate that the BAER can be clinically used in order to diagnose the deafness in dogs.

• 반도체디스플레이기술학회지
• /
• 제9권4호
• /
• pp.7-12
• /
• 2010

Field-emission characteristics of carbon nanotubes(CNTs), which were grown on conical-type tungsten micro-tips by using an electrophoretic deposition(EPD) method, were examined. The EPD method proved to be convenient to manipulate and arrange CNTs from well dispersed suspensions onto such tip-type substrates. The growth rate of CNTs was proportional to the applied d.c. bias voltage and the process time. It was observed from the Raman study that the EPDproduced CNTs showed better crystal qualities with the Raman intensity ratio( $I_D$/$I_G$) of 0.41-0.42 than the CVD-produced CNTs and their crystal qualities could be further improved by thermal annealing. The electron emitters based on the EPDCNTs showed excellent field emission properties, such as the threshold voltage for electron emission of about 620 V and the maximum emission current of about 345 ${\mu}A$. In addition, the EPD-CNTs exhibited the stable long-term(up to 40 h) emission capability and the emission stability was enhanced by thermal annealing.

• 한국광학회지
• /
• 제6권3호
• /
• pp.228-232
• /
• 1995

초고속 광통신을 위한 고속변조용 단일모드 반도체 레이저로서 변조 도핑된 SMQW-PBH-DFB-LD를 제작하고 변조특성을 축정 하였다. 제작된 소자의 최소 임계전류는 16.0mA, 최대 slope efficiency는 0.275mW/mA였다. 고속변조를 위한 활성층의 변조도핑으로 소자의 내부손실은 $37cm^{-1}$로 크게 주어졌으나. 이득계수의 증가에 따라 선폭확대계수는 1.8로 감소되었다. 소신호 변조 특성 측정 결과, $46mA(I_{th}+30mA)$ 에서의 공진주파수 8GHz, -3dB 차단주파수 10GHz 이상으로서 고속변조 특성이 우수한 변조도핑된 SMQW-PBH-DFB-LD를 시험 제작하였다.

• 한국안전학회지
• /
• 제37권6호
• /
• pp.148-157
• /
• 2022

Every year, particularly during the monsoon rainy season, landslides at the Chuncheon province of South Korea cause tremendous damage to lives, properties, and infrastructures. More so, the high rainfall intensity and long rainfall days that occurred in 2020 have increased the water content in the soil, thereby increasing the chances of landslide occurrences. Besides this, the rainfall thresholds and characteristics responsible for the initiation of landslides in this region have not been properly identified. Therefore, this paper addresses the rainfall thresholds responsible for the initiation of landslides at Chuncheon from a regional perspective. Using data obtained from rainfall measurements taken from 2002 to 2011, we identify a threshold relationship between rainfall intensity and rainfall duration for the initiation of landslides. In addition, we identify the relationship between the rainfall intensity using a 3-day, 7-day, and 10-day antecedent rainfall observation. Specifically, we estimate the rainfall data at 8 sites where debris flow occurred in 2011 by kriging. Following this, the estimated data are used to construct the relationship between the intensity (I), duration (D), and frequency (F) of rainfall. The results of the intensity-duration-frequency (IDF) analysis show that landslides will occur under a rainfall frequency below a 2-year return period at two areas in Chuncheon. These results will be effectively used to design structures that can prevent the occurrence of landslides in the future.