• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2005년도 추계 학술대회논문집(수송기계편)
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• pp.63-63
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• 2005

• Proceedings of the Korean Magnestics Society Conference
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• 한국자기학회 2016년도 임시총회 및 하계학술연구발표회
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• pp.34-34
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• 2016

• Current Industrial and Technological Trends in Aerospace
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• 제8권1호
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• pp.62-76
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• 2010

In this paper, recent researches about the unmanned lunar lander development are studied. Objectives of this study are to derive research trends and to identify key design activities especially in early design phase of unmanned lunar lander. Case study covers SELENE-2 of Japan, LEDA and MoonNEXT of ESA, and small and modular spacecraft approach of NASA. Lunar lander concepts proposed for the International Lunar Network Anchor Nodes are also studied. For each lunar lander program, mission requirements are summarized and mission design results are reviewed. Approaches of safe lunar landing including design of navigation, guidance and control, combination of sensors, derived sensor and propulsion performance requirements are also analyzed.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• 제8권4호
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• pp.38-45
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• 1994

It is very imprtant and necessary to predict luminous enviroment in an interior space. This paper has de scribed about energy saving and evaluated interior visual environment in a office building having on/off turning control lighting system utilizing daylight. In order to predict the interior varior illumination distribution, the scale model w a m~a de and examined under various conditions, such ad difference of window glass, and color pattern of wall, floor, and also ceiling lighting system type. Ths paper suggests that basic fundamental data of lighting design ~rformancein the concept and schematic stages of design.

• JOURNAL OF ELECTRICAL WORLD
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• 통권277호
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• pp.63-68
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• 2000

요 몇 해 사이에 고내압$\cdot$대용량 파워디바이스에서는 아주 새로운 진전이 일어나고 있다. 파워일렉트로닉스 장치의 소형화$\cdot$고효율화 및 제어의 고속화 등의 요구에 응할 수 있는 차세대의 새로운 소자가 출현하여 그 제품화가 비약적으로 진전되고 있는 것이다. 새로운 파워디바이스의 대표적인 것으로는 다음의 3가지를 들 수 있다. $\cdot$HVIGBT(High Voltage Insulated Gate Bipolar Transistor Module)$\cdot$HVIPM(High Voltage Intelligent Power Module)$\cdot$GCT(Gate Commutated Turn-off)사이리스터 이들의 파워디바이스를 종래의 GTO(Gate Turn-off) 사이리스터와 비교해 보면 다음과 같은 특징이 있다.(1)GTO 사이리스터가 필요로 했던 스나버회로가 없어도(Snabber-less)턴오프가 가능하며, di/dt 억제용 아노드리액터의 생략 또는 저감이 가능하기 때문에 반도체 부녀회로의 소형화를 기할 수 있다. (2)게이트파워와 전체손실(소자 및 주변회로를 포함)의 저감으로 에너지 절약을 도모할 수 있다. (3)스위칭주파수를 2$\~$3kHz 정도까지 높일 수 있다. 이런 장점 때문에 다음과 같은 용도에의 적용이 기대되고 있다. (1)신간선, 지하철 등의 전철 응용 (2)액티브필터, SVG(무효전력발생장치), SVC(무효전력보상장치) BTB, 가변속 양수발전 스위치 등의 전력응용 (3) 철강압연이나 제지공장용 등의 대용량공업용 컨버터$\cdot$인버터 응용 HVIGBT와 HVIPM은 전철분야에서 신간선의 추진용 컨버터$\cdot$인버터장치와 보조전원장치, 그리고 지하철의 추진용 인버터 장치나 보조전원장치 등에 채용되고 GCT 사이리스터는 전력용 주파수변환기 등에 실용화되고 있다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제16권10호
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• pp.1003-1009
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• 2005

In this paper, small-size high-power single pole double throw(SPDT) switch with defected pound structure(DGS) is presented for wireless broadband internet application. To reduce the circuit size using slow-wave characteristic, the DGS is applied to ${\lambda}/4$ transmission line of the switch and the measured results are compared with them of conventional switch. To secure high degree of isolation, the switch with the DGS is composed of shunt-connected PIN diodes and shows insertion loss of 0.8 dB and isolation more than 50 dB at 2.3 GHz. The size of the switch is reduced about $50\%$ only with the DGS patterns while it has very similar performance to the conventional shunt-type switch.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제16권6호
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• pp.632-643
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• 2005

This paper presents a folded stripline-fed small broadband disk-loaded monopole antenna with vertical ground plane. The bandwidth of the proposed antenna can be enhanced by electromagnetic coupling between the shorted rectangular disk and the probe with folded strip line. The measured impedance bandwidth of the proposed antenna is $37.6\%$ for $VSWR\leq2$ with the center frequency at 2.313 GHz and has the physical dimensions of only $11mm\times11mm\times11mm$ which corresponds to the electrical length of $0.085\lambda_0\times0.085\lambda_0\times0.085\lambda_0$. For improving the radiation pattern characteristics, rectangular slits are inserted in the vertical ground plane. Rectangular slits affect the currents distribution on the ground plane, so that the antenna radiation in the direction of the ground plane is reduced more than 3 dBi. Gain of the antenna is approximately 2.6 dBi within the bandwidth.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제37권8C호
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• pp.637-644
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• 2012

In this paper, a new compact power divider is suggested. Instead of the quarter wavelength transmission line(TX-line)s for the branches of the conventional Wilkinson's power divider design method, we use our composite right- and left-handed(CRLH) TX-line zeroth order resonator(ZOR) bandpass filters of one twelfth wavelength and reduce the physical length of the power divider. Besides, the filters in the branches can secure the passband for power-division. To validate the proposed power divider, we take an L-band for millitary satellaite transponder as the test case and the performances of the circuit and full-wave simulation results with the CRLH properties of the structure are shown with the dispersion curve and E-field at the ZOR. The measurement is compared with the simulation results. Also, the size reduction effect by the proposed scheme is addressed

• Applied Microscopy
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• 제38권3호
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• pp.235-243
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• 2008

A compact soft x-ray microscope operated in the 'water window' wavelength region ($2.3{\sim}4.4nm$) was used for observing cells with nano-scale spatial resolution. To obtain cellular imaging captured with colloidal gold nanoparticles using a compact soft x-ray microscope. The colloidal gold nanoparticles showed higher contrast and lower transmission more than 7 times than that of cellular protein on the soft x-ray wavelength region. The structure and thickness of the cell membrane of the Coscinodiscus oculoides (diatome) and red blood cells were seen clearly. The gold nanoparticles within the HT1080 and MDA-MB 231 cells were seen clearly on the soft x-ray microscopy. The gold nanoparticles were aggregated within vesicles by endocytosis.

• Journal of the Korean Society of Marine Environment & Safety
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• 제29권7호
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• pp.863-870
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• 2023

Ship capsize accidents are common in coastal waters, particularly involving small fishing boats. To prevent there overturing accidents in small fishing boats, their stabilities must be assessed at the initial design step. However, the available information during the initial design step is limited, posing challenges in performing a reliable stability evaluation. Therefore, this study presents a plan to estimate the transverse metacenter (GM) of small fishing boats using parameters such as KM, KG, and TRIM that can be determined at the initial design step. Stability was evaluated by comparing GM with the minimum transverse metacenter (GMmin) specified in the standard safety evaluation criteria for fishing boats. To calculate the required trim value for hydrostatic characteristics using K-SHIP, a stability assessment program provided by the Korea Maritime Safety and Transportation Corporation, the initial trim state is estimated based on the ship lines using the commercial CFD program STAR-CCM+. GM is then calculated by assessing the hydrostatic characteristics in relation to the boat lines using K-SHIP. Furthermore, the stability of the fully loaded state is compared by subtrcating GM from GMmin. One constructed ship is designated as the standard ship, and the stability assessment method proposed in this study is applied to evaluate stability and validate its effectiveness. Consequently, the representative line of a 4.99-ton fishing boat and nine modular lines models derived from it were evaluated, ultimately identifying a relatively superior stability.