• BMB Reports
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• 제30권6호
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• pp.426-430
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• 1997

The helical periodicity of the triple-stranded $(dT)_n{\cdot}(dA)_n{\cdot}(dT)_n$ sequence was determined by measuring gel-mobilities of bent DNA fragments containing the sequence. In the bent DNA fragments, a $GA_{22}G$ $CT_{22}C$ sequence was located between two bent DNA loci composed of six $A_{6}{\cdot}T_{6}$ repeats. and the DNA length between the bent DNA loci was varied by 1 base pair over a full helical turn. The gel mobility of each bent DNA fragment reflected the overall extent of DNA bending and varied with the DNA length between the two bent loci. Mobilities of the bent DNA fragments in 5% polyacrylamide gel were measured after preincubating the DNA fragments both in the presence and absence of $CT_{22}C$ oligonucleotide. By comparing the bent DNA fragments containing an intermolecular triplex structure with those of a genuine duplex structure in the gel mobilities, the helical periodicity of the $T_n{\cdot}A_n{\cdot}T_n$ triplex DNA was determined to be $11.5({\pm}0.3)bp/turn$.

• 전기학회논문지P
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• 제64권3호
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• pp.146-152
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• 2015

In this paper, we propose a boost DC-DC converter using a modification of the passive auxiliary resonant snubber circuit with a DC-DC converter in a typical active auxiliary resonant snubber-bridge inverter. The proposed boost DC-DC converter is small compared to the DC-DC converter according to the soft-switching scheme that requires a general auxiliary switch by realizing the soft switching operation as a DC-DC converter which does not require an auxiliary switch. It is light-weight, switch the turn-on and turn-off switching loss at the time of the superposition of the voltage and current is extremely small, so small. And the reduction of the surge voltage and current of the switch. In addition, the proposed boost DC-DC converter has a high efficiency over a wide load characteristics change area than conventional hard switching PWM boost converter using an RC snubber loss.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.194-196
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• 2001

Light dimming is based on adjusting the voltage which gets to the lamp. Light dimming has been possible for many decades by using adjustable power resistors and adjustable transformers. The power electronics have proceeded quietly since 1960. Between 1960-1970 thyristors and triacs came to market. Using those components it was quite easy to make small and inexpensive light dimmers which have goof efficiency. This type of electronic light dimmers became available after 1970 and are nowadays used in very many locations like homes, restaurants, conference rooms and in stage lighting. But the problem of thyristor dimmer have been that it has poor efficiency and voltage drop. Recently IGBT(Insulated Gate Bipolar Transistor) control is a new way to do light dimming for improving this problems. IGBT dimmer has many other advantages over traditional thyristor dimmer there are no huge current spikes and EMI caused by turn on Using IGBT it is possible to make the turn-off rate relatively slot to achieve quite operations in terms of EMI and acoustical or incandescent lamp filament noise. For the development of IGBT dimmer. This paper shows the effects of IGBT dimmer compared with thyristor dimmer through a simulation using EMTDC.

• Journal of Korean Vacuum Science & Technology
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• 제3권1호
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• pp.38-42
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• 1999

Using the LOCOS process, we have fabricated the lateral type polysilicon field emission triodes with poly-Si/oxide/Si structure and investigated their current-voltage characteristics for three biasing modes of operation. The fabricated devices exhibit excellent electrical performances such as a relatively low turn-on anode voltage of 14 V at VGC = 0V, a stable and high emission current of 92${\mu}$A/triode over 90 hours, a small gate leakage current of 0.23 ${\mu}$A/triode and an outstanding transconductance of 57${\mu}$S/5triodes at VGC = 5V and VAC = 26V. these superior electrical operation is believed to be due to a large field enhancement effect, which is related to the sharp cathode tips produced by the LOCOS process as well as the high aspect ratio (height /radius ) of the cathode tip end.

• International Journal of Aeronautical and Space Sciences
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• 제12권4호
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• pp.365-370
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• 2011

This paper presents the air-to-air missile autopilot design for a $180^{\circ}$ heading reversal maneuver during boost-phase. The missile's dynamics are linearized at a set of operating points for which angle of attack controllers are designed to cover an extended flight envelope. Then, angle of attack controllers are designed for this set of points, utilizing a pole-placement approach. The controllers' gains in the proposed configuration are computed from aerodynamic coefficients and design parameters in order to satisfy designer-chosen criteria. These design parameters are the closed-loop frequency, damping ratio, and time constant; these represent the characteristics of the control system. To cope with highly nonlinear and rapidly time varying dynamics during boost-phase, the global gain-scheduled controller is obtained by interpolating the controllers' gains over variations of the angle of attack, Mach number, and center of gravity. Simulation results show that the proposed autopilot design provides satisfactory performance and possesses good [ed: or "sufficient" or "excellent"] capabilities.

• 한국지진공학회논문집
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• 제8권3호
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• pp.53-62
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• 2004

본 논문에서는 현행 내진설계방법에 따라 설계된 역V형 보통 가새골조 (OCBF)의 비선형 정적 해석을 수행하고, 그 결과를 바탕으로 초과강도계수, 연성계수, 반응수정계수 및 변위 증폭계수 등을 산정하였다. 해석결과에 따르면 대부분의 해석모델에서 현행 내진설계 기준에서 제시한 값보다 작은 초과강도계수 및 반응수정계수 값을 가지는 것으로 나타났다. 그러나 수직 보강 기둥 (zipper column)으로 가새를 보강한 경우 초과강도계수 및 반등수정계수는 보통 가새 구조물에 비하여 상당히 증가하는 것으로 나타났다.

• 대한기계학회논문집A
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• 제28권2호
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• pp.149-157
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• 2004

Implicit finite element analysis of the flat surface-straight edge hemming process is performed by using a commercial code ABAQUS/Standard. Methods of finite element modeling for springback simulation and contact pair definition are discussed. An optimal mesh system is chosen through the error analysis that is based on the smoothing of discontinuity in the state variables. This study has focused on the investigation of the influence of process parameters in flanging, pre-hemming and main hemming on final hem quality, which can be defined by turn-down, warp and roll-in. The parameters adopted in this parametric study are flange length, flange angle, flanging die corner radius, face angle and insertion angle of pre-hemming punch, and over-stroke of pre-hemming and main hemming punches.

• 복식문화연구
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• 제27권1호
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• pp.57-63
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• 2019

Due principally to the desire to seek lower production costs, the bulk of the world's textile and clothing manufacture migrated to low-cost zones, mainly outside Europe, over the course of the late-twentieth century. In the early-twenty-first century, fast fashion became a dominant force worldwide, with 'Western' retail buyers hunting cheaper deals from clothing manufacturers (mainly in Asia), and with occasional disasters not changing matters beyond the duration of a fashion season. Progressively, seams became narrower, cheaper raw materials were used and durability was no longer an aim. Why bother to do otherwise? This was what the 'Western' consumer wanted: fashion to be worn only a few times and then discarded, despite the fact that vast amounts of human, technological and financial resources were wasted in such a quest. By the end of the second decade of the twenty-first century, the production of textile and clothing products continued to contribute substantially to global warming. This paper reviews briefly the current conditions of manufacture, and argues that the research agenda should be focused on addressing the implications of a progressively changed focus, not on fast-fashion products, but instead on the production of products with greater durability. Meanwhile 'Western' consumers need to turn away from fast fashion and realise that waste is bad for their economy and their society. It is argued further, that after a period of re-adjustment, substantial financial rewards await the national textile and clothing industries that undergo such a turn around.

• 천문학회보
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• 제44권1호
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• pp.34.1-34.1
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• 2019

To study the formation and evolution of stellar bars and gaseous nuclear rings in barred galaxies in realistic environments, we run fully self-consistent three-dimensional simulations of isolated disk galaxies. We consider two groups of models with cold or warm disks that differ in the radial velocity dispersion. We also vary the gas fraction of the disks. We found that a bar forms earlier and more strongly as the gas fraction increases in the cold disks, while the gas delays the bar formation in the warm disks. The bar formation enhances a central mass concentration which in turn weakens the bar strength temporarily, after which the bar regrows to become stronger in a model with a smaller gas fraction in both cold and warm disks. Although all bars rotate fast in the beginning, they rapidly turn to slow rotators. Gas infalling to the central region forms a dense star-forming nuclear ring. The ring size is very small when it first forms and grows over time. The ring star formation is episodic and bursty due to star formation feedback, and has a good correlation with the mass inflow rate to the ring. Some expanding shells produced by star formation feedback are sheared out in the bar regions and collide with dust lanes to appear as filamentary interbar spurs.

• 한국융합학회논문지
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• 제11권3호
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• pp.253-261
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• 2020

본 연구의 목적은 S14 등급 장애인 수영 국가대표 선수의 최근 4년간 배영 100m 경기에 대한 경기운영능력을 분석하는 것이다. 분석 변인은 출발 구간의 반응 시간, 잠영 거리 및 시간, 속도, 턴 구간의 턴 거리, 시간, 속도, 질주구간의 스트로크 횟수, 빈도, 길이, 효율성이다. 그 결과, 2015년에는 처음 50m 구간까지 서서히 질주하고, 마지막 100m 구간까지 빠르게 질주하는 경기운영을 보였으나 2016년부터 2018년에는 처음 50m 구간까지 빠르게 질주하고 마지막 100m 구간까지 처음에 비하여 약간 느리게 질주하는 경향을 보였다. 또한, 잠영시간도 해를 거듭할수록 증가하는 경향을 보였으며, 2017년에 잠영거리와 시간이 가장 크게 나타났으며, 잠영속도도 가장 빠른 것으로 나타났다. 그리고 4년간 평균 턴 거리는 약 7.51 m, 턴 시간은 4.34초, 턴 속도는 1.73 m/s로 나타났다. 마지막으로 처음 50m 구간의 스트로크 효율성은 해를 거듭할수록 향상되었으나 50-100m 구간에서는 2017년에 가장 효율적인 스트로크를 구사하였다. 이 결과는 지적장애인 수영 선수 훈련에 유용한 자료로 활용될 것이라 기대한다.