• Journal of Electrical Engineering and information Science
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• v.3 no.2
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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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• v.14 no.1
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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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• v.52 no.8
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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).

• Tunnel and Underground Space
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• v.9 no.2
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• pp.102-113
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• 1999

Two-dimensional and three-dimensional DEM programs, UDEC and 3DEC, were used to investigate the mechanical stability of the conceptual design of deposition drift and deposition holes constructed in a crystalline rock mass. From the simulations, the influence of discontinuities, the number of deposition holes, and deposition hole interval on the stability of deposition drift and deposition holes could be determined. From the two-dimensional and three-dimensional analysis. it was concluded that three-dimensional analysis should be carried 7ut fur deriving reliable conclusions. Even though the deposition hole interval changed from 8 m to 3 m, which did not damage the mechanical stability of the deposition drift.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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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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• v.1 no.3_4
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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.

• Korean Journal of Plant Resources
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• v.14 no.1
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• pp.60-64
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• 2001

This study was carried out to investigate effects of sowing dates and method on major agronomic characteristics of Dendropanax morbifera $L_{EV}$. in southern area of Korea. The number of days from sowing to emergence was recognized liner negative correlation between sowing days. Dendropanax morbifera was sowed at seven different dates(from Dec.20 to Feb.20 at 30 days interval, from Mar, 1 to Apr. 15 at 15 days interval) in pot culture. In sowing date at Mar. 15, germination rate and early growth were good in pot. Dendropanax morbifera was sowed at five different dates(from Dec.20 to Apr.15 at 15 days interval) in field culture. In sowing date at Apr.15, germination rate and early growth were good in field culture.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.2
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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.

• Journal of KIISE:Databases
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• v.27 no.1
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• pp.90-100
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• 2000

We propose, in this paper, a new query expansion technique with term reweighting. All terms in the documents feedbacked from a user, excluding stopwords, are selected as candidate terms for query expansion and reweighted using the relevance degree which is calculated from the term-distribution similarity between a candidate term and each term in initial query. The term-distribution similarity of two terms is a measure on how similar their occurrence distributions in relevant documents are. The terms to be actually expanded are selected using the relevance degree and combined with initial query to construct an expanded query. We use KT-set 1.0 and KT-set 2.0 to evaluate performance and compare our method with two methods, one with no relevance feedback and the other with Dec-Hi method which is similar to our method. based on recall and precision.

• The Journal of Korean Physical Therapy
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• v.24 no.4
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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.