• Journal of Electrical Engineering and information Science
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• 제3권2호
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• pp.261-266
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• 1998

This paper describes the fabrication and characterization of dual-polysilicon gated surface channel 0.1$\mu\textrm{m}$ CMOSFETs using BF2 and arsenic as channel dopants. We have used and LDD structure and 40${\AA}$ gate oxide as an insulator. To suppress short channel effects down to 0.1$\mu\textrm{m}$ channel length, shallow source/drain extensions implemented by low energy implantation and SSR(Super Steep Retrograde) channel structure were used. The threshold voltages of fabricated CMOSFETs are 0.6V. The maximum transconductance of nMOSFET is 315${\mu}$S/$\mu\textrm{m}$, and that of pMOSFET is 156 ${\mu}$S/$\mu\textrm{m}$. The drain saturation current of 418 ${\mu}$A/$\mu\textrm{m}$, 187${\mu}$A/$\mu\textrm{m}$ are obtained. Subthreshold swing is 85mV/dec and 88mV/dec, respectively. DIBL(Drain Induced Barrier Lowering) is below 100mV. In the device with 2000${\AA}$ thick gate polysilicon, depletion in polysilicon near the gate oxide results in an increase of equivalent gate oxide thickness and degradation of device characteristics. The gate delay time is measured to be 336psec at operation voltage of 2V.

• ETRI Journal
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• 제14권1호
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• pp.52-65
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• 1992

전자선 직접묘사 (E-beam direct writing lithography) 방법을 이용하여 $0.2\mum$ 과 $0.3\mum$ 의 게이트길이를 가지는 NMOS 트랜지스터를 제작하였다. 게이트만 전자선 직접묘사 방법으로 정의하고 나머지는 optical stepper를 이용하는 Mix & Match 방식을 사용하였다. 게이트산화막의 두께는 최소 6nm까지 성장시켰으며, 트랜지스터구조로서는 lightly-doped drain(LDD) 구조를 채택하였다. 짧은 채널효과 및 punch through를 줄이기 위한 방안으로 채널에 깊이 붕소이온을 주입하는 방법과 well을 고농도로 도핑하는 방법 및 소스와 드레인에 $p^-$halo를 이온주입하는 enhanced lightly-doped drain(ELDD) 방법을 적용하였으며, 제작후 성능을 각각 비교하였다. 제작된 $0.2\mum$의 게이트길이를 가지는 소자에서는 문턱전압과 subthreshold기울기는 각각 0.69V 및 88mV/dec. 이었으며, Vds=3.3V에서 측정한 포화 transconductance와 포화 드레인전류는 각각 200mS/mm, 0.6mA/$\mum$이었다. $0.3\mum$소자에서는 문턱전압과 subthreshold 기울기는 각각 0.72V 및 82mV/dec. 이었으며, Vds=3.3V에서 측정한 포화 transconductance는 184mS/mm이었다. 이러한 결과는 전원전압이 3.3V일 때 실제 ULSI에 적용가능함을 알 수 있다.

• Nuclear Engineering and Technology
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• 제52권8호
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• pp.1714-1723
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• 2020

This study aims at characterizing the rheological properties of uranium oxide powders for nuclear fuel pellets manufacturing. The flowability of these powders must be compatible with a reproducible filling of press molds. The particle size distribution is known to have an impact on the rheological properties and fine particles (<100 ㎛) are suspected to have a detrimental effect. In this study, the impact of the particle size distribution on the rheological properties of UO₂ powders was quantified, focusing on the influence of fine particles. Two complementary approaches were used. The first approach involved characterizing the powder in a static state: density, compressibility and shear test measurements were used to understand the behavior of the powder when it is transitioned from a static to a dynamic state (i.e., incipient flow conditions). The second approach involved characterizing the behavior of the powder in a dynamic state. Two zones, corresponding to two characteristic behaviors, were demonstrated for both types of measurements. The obtained results showed the amount of fines should be kept below 10 % wt to ensure a robust mold filling operation (i.e., constant mass and production rate).

• 터널과지하공간
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• 제9권2호
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• pp.102-113
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• 1999

결정질 암반에 설치되는 처분공과 처분터널의 구조적 안정성을 평가하기 위해 UDEC과 3DEC을 이용하여 2차원해석과 3차원 해석의 결과를 비교 분석함으로써 불연속면의 존재, 처분공 사이의 간격 등이 처분터널과 처분공의 안정성에 미치는 영향을 파악하고자 하였다. 2차원 및 3차원 불연속 해석모델에서 최대주응력 및 파괴발생 가능성이 큰 지점은 터널과 불연속면 사이의 암반이다. 또한 처분공을 포함하는 해석단면에 대한 2차원 및 3차원 해석결과, 합리적인 결과를 얻기 위해서는 3차원 해석이 필요함을 제시할 수 있었다. 그리고 처분공 간격이 8m에서 3m로 감소하더라도 처분터널의 역학적인 안정성에는 큰 변화가 발생하지 않는 것으로 나타났다

• 천문학회보
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• 제39권2호
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• pp.60.1-60.1
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• 2014

In the center of an Active Galactic Nuclei(AGN) is a supermassive black hole which accretes matter from its surroundings. The radio-loud AGN launch two relativistic jets perpendicular to the accretion disk which terminates into radio lobes located up to megaparsec away. Blazars form a small subset of radio-loud AGNs with one of two relativistic jets pointing toward the observer's line of sight. Many blazars often show flares at different frequencies. And these flares at different frequencies are known that they often correlate with each other. In 2013 December, there was a gamma-ray flare in 3C 279, one of the brightest blazars, Dec 2013. So we want to reveal that whether this flare correlates with radio flare or not, and where the flare originate. With polarization observation at radio frequencies, we can study the physical properties of the magnetic field in the innermost regions of the relativistic jets. Therefore, we have conducted polarization monitoring of this source from Dec. 2013 to Jun. 2014 with KVN(Korea VLBI Network) radio telescopes at 22, 43 and 86GHz. Here we present the initial results of the monitoring of 3C 279. We prospect that we can reveal the origin of this gamma-ray flare by comparing with our radio data.

• Carbon letters
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• 제1권3_4호
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• pp.148-153
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• 2001

The initial irreversible capacity, $Q_i$, is one of the parameters to express the material balancing of the cathode to anode. We introduced new terms, which are the initial intercalation Ah efficiency (IIE) and the initial irreversible specific capacity at the surface ($Q_{is}$), to express precisely the irreversibility of an electrode/electrolyte system. Two terms depended on kinds of active-materials and compositions of the electrode, but did not change with charging state. MPCF had the highest value of IIE and the lowest value of $Q_{is}$ in 1M $LiPE_6$/EC + DEC (1 : 1 volume ratio) electrolyte. IIE value of $LiCoO_2$ electrode was 97-98%, although the preparation condition of the material and the electrolyte were different. $Q_{is}$ value of $LiCoO_2$ was 0~1 mAh/g. MPCF-$LiCoO_2$ cell system had the lowest of the latent capacity. $Q_{is}$ value increased slightly by adding conductive material. IIE and $Q_{is}$ value varied with the electrolyte. By introducing PC to EC+DEC mixed solvent, IIE values were retained, but $Q_{is}$ increased. In case of addition of MP, IIE value increased and $Q_{is}$ value also increased a little.

• 한국자원식물학회지
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• 제14권1호
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• pp.60-64
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• 2001

우리나라 황칠나무 주요 자생지인 남부도서지역의 완도지방에서 황칠나무의 적정 파종기를 구명하여 자생지 보호와 농가의 재배면적 확대 그리고 관상가치가 높은 실생 파종묘의 재배법을 체계적으로 확립 하고자 본시험을 실시한 결과는 다음과 같다. 1. 비닐하우스를 이용하여 황칠나무의 종자를 포트에 파종할 경우 3월 중순 파종이 출현율이 높고, 초기생육이 양호하여 알맞은 파종기로 판단된다. 2. 노지에 황칠나무 종자를 직파할 경우 4월 상순 파종이 종자의 출현율이 높고, 생육이 양호하여 알맞은 파종기로 생각된다. 3. 황칠나무의 적정 파종방법으로는 포트파종이 노지 파종보다 발아율이 높고, 묘목의 수고와 경직경이 커서 초기생육이 양호하여 알맞은 파종방법으로 생각된다.

• 한국전기전자재료학회논문지
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• 제33권2호
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• pp.93-98
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• 2020

We investigated the effect of a post-annealing process using ultraviolet (UV) light on the electrical properties of solution-processed InZnO (IZO) thin-film transistors (TFTs). UV light was irradiated on IZO TFTs for different time periods of 0s, 30s, and 90s. We measured transfer and retention stability curves to evaluate the performance of the fabricated TFTs. In addition, we measured height, amplitude, and phase AFM images to analyze changes in the surface and morphology of the devices. AFM measurements were performed by setting the drive amplitude of the cantilever tip to 47.9 mV in tapping mode, then dividing the device surface into 500 nm × 500 nm. In the case of IZO TFT irradiated with UV for 30s, the electron mobility and I_on/I_off ratio were improved, the threshold voltage was reduced by approximately 2 V, and the subthreshold swing also decreased form 1.34 V/dec to 1.11 V/dec.

• 한국정보과학회논문지:데이타베이스
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• 제27권1호
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• pp.90-100
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• 2000

본 논문에서는 사용자의 적합 피드백을 기반으로 피드백 문서들에서 발생하는 용어들과 초기 질의와의 관련 정도를 이용하여 용어의 가중치를 산정하는 방법에 대하여 제안한다. 피드백 문서들에서 발생하는 용어들 중에서 불용어를 제외한 모든 용어들을 질의로 확장될 수 있는 후보 용어들로 선택하고 피드백 문서들에서 발생 빈도 유사성을 이용하여 초기 질의에 대한 후보 용어의 관련 정도를 산정하며, 피드백 문서들에서의 가중치와 관련 정도를 결합하여 후보 용어들의 가중치를 산정 하였다. 본 논문에서는 성능을 평가하기 위하여 KT-set 1.0과 KT-set 2.0을 사용하였으며, 성능의 상대적인 평가를 위하여 질의어를 확장하지 않은 방법, Dec-Hi방법들을 정확률-재현율을 사용하여 평가 하였다.

• The Journal of Korean Physical Therapy
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• 제24권4호
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• pp.241-246
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• 2012

Purpose: We investigated the effect of postural stability and balance with foot orthotics in hemiplegic patients. Methods: The subjects enrolled in this study were 16 hemiplegic patients who were examined for balance ability, weight distribution, and limits of stability with or without foot orthotics insole. Balance was measured according to a stance position by BIORESCUE: static balance open eyes (SEO), static balance close eyes (SEC), dynamic balance open eyes (DEO), dynamic balance close eyes (DEC), right and left weight distribution (RLWD), anterior and posterior weight distribution (APWD) and limit of stability (LOS). The data were analyzed with SPSS window version 18.0 (IBM Co., Armonk, NY, USA). Results: The results were of significant changes to the SEO (p<0.05), RLWD (p<0.05), APWD (p<0.05), and LOS (p<0.05). The SEC, DEO and DEC were not found to be statistically significant. Conclusion: It was found that foot orthotics affected the balance for hemiplegic patients. Therefore, it is thought to help fall prevention to measure the balance ability.