• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.839-841
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• 2015

본 연구에서는 비대칭 이중게이트 MOSFET의 채널길이와 채널두께의 비에 따른 드레인 유도 장벽 감소 현상의 변화에 대하여 분석하고자한다. 드레인 전압이 소스 측 전위장벽에 영향을 미칠 정도로 단채널을 갖는 MOSFET에서 발생하는 중요한 이차효과인 드레인 유도 장벽 감소는 문턱전압의 이동 등 트랜지스터 특성에 심각한 영향을 미친다. 드레인 유도 장벽 감소현상을 분석하기 위하여 포아송방정식으로부터 급수형태의 전위분포를 유도하였으며 차단전류가 $10^{-7}A/m$일 경우 비대칭 이중게이트 MOSFET의 상단게이트 전압을 문턱전압으로 정의하였다. 비대칭 이중게이트 MOSFET는 단채널효과를 감소시키면서 채널길이 및 채널두께를 초소형화할 수 있는 장점이 있으므로 본 연구에서는 채널길이와 두께 비에 따라 드레인 유도 장벽 감소를 관찰하였다. 결과적으로 드레인 유도 장벽 감소 현상은 단채널에서 크게 나타났으며 하단게이트 전압, 상하단 게이트 산화막 두께 그리고 채널도핑 농도 등에 따라 큰 영향을 받고 있다는 것을 알 수 있었다.

• Journal of Astronomy and Space Sciences
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• v.12 no.1
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• pp.14-20
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• 1995

We calculated the wind velocities for 32 Cyg in order to understand how influence a damping length on the wind of supergiant driven by Alfven waves. Four cases, $\lambda$=0.9, 1.0, 5.0, the ratio of the damping length to the supergiant's radius, and the damping length increasing linearly with the distance from the star, were compared. The results showed the forces by Alfven waves gave the major contribution to the wind velocity but the forces by the pressure and gravitation did little. The model for the damping length with the linear relation showed the rapid increased due to short damping length near the surface of the star.

• Explosives and Blasting
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• v.21 no.1
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• pp.19-27
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• 2003

국내 석회석 광산에서는 벤치 발파패턴을 현장의 KNOW-HOW에 따라 가장 경제저인 발파패턴을 적용하고 있다. 그러나 인건비 재료비등 제반경비가 상승함에 따라 좀 더 효율적인 발파방법의 개선이 요구되고 있는 바, 현 석회석 광산에서의 발파패턴을 보다 개선하여 경제적인 발파패턴을 적용하고, 그에 따른 고려해야 할 사항들을 본 논문에서 연구 하고자 한다. 따라서 국내 석회석 광산의 발파 패턴과 외국의 광산발파 패턴을 비교하고, 수치해석을 적용하여 기존의 발파 패턴에서 장약길이, 공간격, 장약량의 변화, 천공경은 102mm에서 115mm로 변화하고 장양방법을 단일장약에서 이중장약으로 변화하여 동해 쌍용자원에서 시험을 실시하였다. 연구 결과 장약길이의 20% 감소는 Power Factor를 (20%)낮게 하나, 파쇄효과는 28% 감소하고 Back Break가 (7%)이상 발생하였으며, 천공경을 115mm로 적용하고, 장약길이를 11% 감소를 위하여 이중장약을 적용하여 Power Factor를 10% 낮게 하였을 때 파쇄효과는 22.45%가 증대되었으며, 기존 동일 패턴에 Booster를 추가로 적용하였을 때 파쇄효과는 13.21% 가 증대되었고, Power Factor는 11% 가 감소되는 것을 알 수 있었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.19-22
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• 2004

In the future engine with high performance, the gas-liquid scheme injectors will be adopted and the role of the injector as an acoustic resonator is investigated as an advanced study The injector can play a significant role in acoustic damping and the optimum length of the injector to maximize the damping capacity is calculated as a function of baffle length.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.54-61
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• 2016

Because a word is the basic unit of language processing, studies of the word recognition processing and the variables that contribute to word recognition processing are very important. Word frequency and word length are recognized as important factors on word recognition. This study examined the effects of those two variables on the Korean word recognition processing. In Experiment 1, two types of Hangul words, pure Hangul words and Hangul words with Hanja counterparts, were used to explore the frequency effects. A frequency effect was not observed for Hangul words with Hanja counterparts. In Experiment 2, the word length was manipulated to determine if the word length effect appears in Hangul words. Contrary to the expectation, one syllable words were processed more slowly than two syllable words. The possible explanations for these results and future research directions are discussed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.17-20
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• 2007

Effect of radial position of half-wave resonator is investigated experimentally for acoustic damping of tangential mode in a combustion chamber by adopting acoustic cold test. When resonator with optimal tuning length is installed， damping is enhanced as its radial location is away from the center of the faceplate. And, radial profile of damping factor is similar to that of the amplitude of the acoustic mode to be damped. As the location is close to the center, acoustic damping is mitigated and independent on the resonator length. on the other hand， the resonator with non-optimal length dose not show any effect of its radial position.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.10
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• pp.15-22
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• 2008

The bulk-planer MOSFET has a scaling limitation due to the short channel effect (SCE). The Double-Gate MOSFET (DG-MOSFET) is a next generation device for nanoscale with excellent control of SCE. The quantum effect in lateral direction is important for subthreshold characteristics when the effective channel length of DG-MOSFET is less than 10nm, Also, ballistic transport is setting important. This study shows modeling and design issues of nanoscale DG-MOSFET considering the 2D quantum effect and ballistic transport. We have optimized device characteristics of DG-MOSFET using a proper value of $t_{si}$ underlap and lateral doping gradient.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.86-91
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• 2016

Convenient design guideline for Waveguide-below-cutoff (WBC) array is proposed to obtain the minimum waveguide length for electromagnetic pulse (EMP) shielding. The analysis includes circular, rectangular, and hexagonal WBC, determine the total length of the waveguide. When the unit side of rectangular WBC and the diagonal line of hexagonal WBC are given as 30 mm, the length of hexagonal WBC is 5 mm shorter than rectangular case with shielding effectiveness (SE) 80 dB. The length difference is deepened with SE of 100 dB, which shows approximately 30 mm shorter length for hexagonal case than others. In addition, hexagonal WBC requires much shorter length than circular WBC. In conclusion, hexagonal case is the most effective with respect to flow velocity and pressure loss for equivalent SE.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.5
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• pp.79-86
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• 2005

The role of the injector as an acoustic resonator is studied for the high performance rocket engine adopting the gas-liquid scheme injector. Acoustic behavior in the combustor with single injector is investigated numerically adopting linear acoustic analysis for cold condition. Acoustic-damping effect of the injector is evaluated by damping factor as a function of the injector length. From the numerical results, it is found that the injector can play a significant role in acoustic damping and the optimum length of the injector corresponds to half of a full wavelength of the longitudinal mode with the acoustic frequency to be damped in the chamber. In baffled chamber, the optimum lengths of the injector are calculated as a function of baffle length for both cold and hot conditions.

• The KIPS Transactions:PartA
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• v.13A no.1 s.98
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• pp.57-70
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• 2006

This paper describes a new effective algorithm to estimate routing congestion and to resolve highly congested regions for a given detailed placement. The major features of the proposed technique can be summarized as follows. Firstly, if there are congested regions due to some nets which pass through the regions it can determine which cells affect those congested spots seriously and moves some of them to resolve congestion effectively. Secondly, since the proposed technique uses the ripple movement technique to move cells it resolves congestion without sacrificing wire length. Thirdly, we use an efficient incremental data structure to trace the changes in congestion and wire length as cells move. Hence, selection of cells to move could be very accurate and fast in the course of iteration. Finally, although an MST net model is used to resolve congestion in this paper, proposed technique can be work with any net model. Particularly, if proposed technique can obtain routing information from a real router, congestion can be resolved more effectively. Experimental results show that the proposed technique can resolve congestion effectively and efficiently without sacrificing wire length.