• 대한기계학회논문집
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• 제12권6호
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• pp.1282-1289
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• 1988

본 연구에서는 형태와 특성이 다른 솔레노이드 밸브를 사용한 위치제어 시스 템에 위에서 언급한 두가지 단속적 제어 방법을 적용하여 이들 밸브의 형태와 특성이 시스템의 응답특성에 미치는 영향을 실험적으로 규명하고 실린더 내의 압력 변화에 미 치는 영향도 조사하였다.

• Journal of Electrical Engineering and information Science
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• 제2권5호
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• pp.129-133
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• 1997

A circuit model for a field emission triode has been proposed. The model parameters have been extracted from he fabricated silicon tip array and verified by comparing with the results simulated by circuit simulator(SPICE). The cut-off frequency can be calculated from the parametric capacitance and the transconductance values extracted from measurements. For the field emission triode, the capacitance of 3.45fF/tip and the transconductance of 0.94nS/tip have been measured under the emission current of 4.1nA/tip. From these values, the cut-off frequency is predicted to be 43 kHz but th measured one came out to be 6 kHz. because o the parasitic capacitance components.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.359-360
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• 2015

10kV IGCT has been recently developed and has the potential to push wind turbine systems to higher power and voltage rating. Converters employing IGCTs need snubber and OVP circuit to limit the rate of rise of current and peak over voltage across IGCT during turn on and off state respectively. The conventional RCD snubber which is used in such power converter dissipates a significant amount of power. In order to reduce the amount of energy lost by conventional RCD snubber, this paper proposes an isolated inductor snubber circuit that not only meets all of the IGCTs characteristics during on and off-state but also significantly saves the power loss. Loss analysis of conventional di/dt snubber and OVP circuit is performed for the 3-level NPC type back-to-back VSC supplied from grid voltage of 6.9kV. In comparison with the conventional snubber, isolated inductor snubber has a fewer number of components and improved efficiency leading to a reliable and efficient wind turbine systems.

• 한국초전도ㆍ저온공학회논문지
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• 제25권3호
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• pp.49-55
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• 2023

This paper presents the design of a re-liquefaction system as a BOG (boil-off gas) handling process in liquid hydrogen transport vessels. The total capacity of the re-liquefaction system was assumed to be 3 ton/day, with a BOR (boil-off rate) of 0.2 %/day inside the cargo. The re-liquefaction cycle was devised using the He-Brayton Cycle, incorporating considerations of BOG capacity and operational stability. The primary components of the system, such as compressors, expanders, and heat exchangers, were selected to meet domestically available specifications. Case studies were conducted based on the specifications of the components to determine the optimal design parameters for the re-liquefaction system. This encompassed variables such as helium mass flow rate, the number of compressors, compressor inlet pressure and compression ratio, as well as the quantity and composition of expanders. Additionally, an analysis of exergy destruction and exergy efficiency was carried out for the components within the system. Remarkably, while previous design studies of BOG re-liquefaction systems for liquid hydrogen vessels were confined to theoretical and analytical realms, this research distinguishes itself by accounting for practical implementation through equipment and system design.

• Journal of Plant Biotechnology
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• 제47권3호
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• pp.185-193
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• 2020

최근, 유전자교정 작물의 상업화 승인 건수가 급속하게 늘어나고 있으며, 국내에서도 유전자교정 작물의 개발에 대한 집중적인 투자를 통하여 국제경쟁력을 높이기 위하여 노력하고 있다. 그러나 기존의 유전자변형작물의 상업화 과정에서 끊임없이 제기되어온 인체 및 환경에 대한 잠재적인 위해성 논란이 유전자교정 작물에 대하여서도 제기되고 있다. 특히, 비의도적 돌연변이(off-target)가 가장 큰 논란의 중심이 되고 있다. 따라서 본 리뷰는 식물이 내포하고 있는 장점인 배수체, 체세포 돌연변이 그리고 자연 상태에서 아그로박테리아의 T-DNA 단편의 수평 전이로 창출된 자연적인 유전자변형작물과 기존에 상업화가 승인된 유전자변형작물 이벤트들의 게놈 내 비의도적 돌연변이 사례 등을 검토한 결과 유전자교정 작물에서 나타나는 대부분의 비의도적 돌연변이는 인체 및 환경에 미칠 수 있는 위해성을 우려할 만한 수준이 아니라고 할 수 있었다. 이에, 유전자교정 작물의 안전성 평가를 위하여 새로운 규정을 제정할 필요가 없으며 기존의 유전자변형작물의 안전 관리규정을 일부 "용어의 정의" 등만 개정하여 적용하면 충분할 것으로 사료 되었다.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2007년도 학술대회
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• pp.26-26
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• 2007

• 디지털콘텐츠
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• 6호통권73호
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• pp.76-82
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• 1999

Java 2 자체는 12월4일 출시되었으며 개발을 위한 소스코드가 무료로 제공되었다. 이는 크나큰 변화로 Kick-Off 회장은 박수갈채가 터져 나왔다. 이것으로 올 6월15일 샌프란시스코에서 개최될 JavaOne은 전에 없던 성황을 이룰 것 같다.

• 한국운동역학회지
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• 제17권2호
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• pp.157-166
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• 2007

This study was to compare the major kinematic factors between the success and failure group on performing the back somersault motion in floor exercise. Three gymnasts(height : $167.3{\pm}2.88cm$, age : $22.0{\pm}1.0years$, body weight : $64.4{\pm}2.3kg$) were participated in this study. The kinematic data was recorded at 60Hz with four digital video camera. Two successful motions and failure motions for each subject were selected for three dimensional analysis. 1. Success Trail It was appear that success trail was larger than failure group in projection velocity, but success trail was smaller than failure trail in projection angle. Also it was appear that success trail was longer than failure group in the time required. Hand segment velocity and maximum velocity in success trail were larger than those in failure trail, and this result was increasing the projection velocity and finally increasing the vertical height of center of mass. At the take-off(event 2), flection amount of hip and knee joint angle was contributed to the optimal condition for the take-off and at the peak point, hip and knee joint angle was maximum flexed for reducing the moment of inertia. Also in this point, upper extremities of success trail extended more than those of failure trail. in this base, success trail in upward phase(p3) 2. Failure Trail It was appear that failure trail was smaller than success trail in projection velocity, but failure trail was larger than success trail in projection angle. Also it was appear that failure trail was more short than success trail in the time required. Hand segment velocity and maximum velocity in failure trail were smaller than those in success trail, and this result was reducing the projection velocity and finally reducing the vertical high of center of mass. At the take-off(event 2), flection amount of hip and knee joint angle wasn't contributed to the optimal condition for the take-off and at the peak point, hip and knee joint angle wasn't maximum flexed for reducing the moment of inertia. Also in this point, upper extremities of failure trail didn't extended more than those of success trail.

• Journal of Information Display
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• 제9권4호
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• pp.21-29
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• 2008

We studied both the wavelength and intensity dependent photo-responses (photofield-effect) in amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs). During the a-IGZO TFT illumination with the wavelength range from $460\sim660$ nm (visible range), the off-state drain current $(I_{DS_off})$ only slightly increased while a large increase was observed for the wavelength below 400 nm. The observed results are consistent with the optical gap of $\sim$3.05eV extracted from the absorption measurement. The a-IGZO TFT properties under monochromatic illumination ($\lambda$=420nm) with different intensity was also investigated and $I_{DS_off}$ was found to increase with the light intensity. Throughout the study, the field-effect mobility $(\mu_{eff})$ is almost unchanged. But due to photo-generated charge trapping, a negative threshold voltage $(V_{th})$ shift is observed. The mathematical analysis of the photofield-effect suggests that a highly efficient UV photocurrent conversion process in TFT off-region takes place. Finally, a-IGZO mid-gap density-of-states (DOS) was extracted and is more than an order of magnitude lower than reported value for hydrogenated amorphous silicon (a-Si:H), which can explain a good switching properties observed for a-IGZO TFTs.

• 대한전자공학회논문지SP
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• 제47권5호
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• pp.9-17
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• 2010

이 연구는 다양한 라우드 스피커 구성인 2-horizontal, 2-vertical, triplet 라우드 스피커 구성에서 UHD TV를 위한 가상 음상의 인지 위치 결과를 제시한다. 비등간격 라우드 스피커 구성에서 가상 음상을 생성하기 위해 잘 알려진 vector-based amplitude panning 알고리즘을 수정하여 적용하였다. 실제 상황에서의 위치 인지 성능을 평가하기 위해, 청취 평가는 일반적인 청취환경에서 TV의 on-axis와 off-axis에서 수행되었다. 인지 각도의 모호함에 의한 오차를 줄이기 위해 각도 조정 테스트 방법이 옥타브 밴드 신호의 각도 평가에 이용되었다. 피실험자는 실제 음원과 가상 조정된 음원의 각도가 일치할 때까지 조정각도를 변화하였다. 공간적 블러링은 각 밴드에서 인지된 조정 각도의 차이를 비교하여 측정되었다. 청취 평가 결과는 triplet panning 방법이 vertical panning 방법보다 on-axis와 off-axis 둘 다, 인지 위치와 공간적 블러링 관점에서 더 나은 성능을 보여주었다.