• Journal of the Society of Naval Architects of Korea
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• v.44 no.2 s.152
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• pp.101-110
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• 2007

Recently, rudder erosion due to cavitation frequently has occurred at large high speed container carriers. Especially, in the case of a horn-type rudder, the rudder erosion is severe around a gap. The gap-flow characteristics are investigated through a computational method to understand the effects of a gap on the cavitation and rudder efficiency. A viscous flow theory utilizing a cavitation model is applied to calculate the flow around idealized 2-dimensional rudder sections in a full scale. The effects of gap clearance and flow-control projection are also investigated. From the computational results, the mass flow rate through a gap is found to be one of the important parameters to affect the cavitation and rudder efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.4
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• pp.335-341
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• 1991

We derive the radiation field equation at the naar field region to analyse EMI by the rectangular horn antenna. The EMI loadk current calculated from the load current induced on the transmission line being close to the rectangular horn antenna using the field theory and the transmission line theory. We find the conditions minimizing the EMI from the load current transfer function of distance, frequency and impedances at sending and receiving end. The smaller sending end impedance, the larger EMI load current and the larger sending impedance, the smaller EMI load current.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.2 s.332
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• pp.87-92
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• 2005

In this paper, adaptive bias circuit and PBG structure have been employed to suppress IMD and improve PAE (Power Added Efficiency) of the power amplifier. It is controlling the gate 'dc' bias voltage with the envelope of the input RF signal. and The PBG structure has been employed on the output port of power amplifier . The proposed power amplifier using adaptive bias circuit and PBG has been improved the IMG by 3 dBc, and the average PAE by $35.54\%$, respectively.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.3
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• pp.143-149
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• 2000

Grinding technology in morden industry society is focusing on research and development for grinding stone and machin-ing parts for the purpose of high accuracy and high efficiency of products. But in order to equip the high technology and high accuracy of micro stone which is one of grinding stone a continuous effort on R& D is require. In this study the honing processing work of 2 cycle engine cylinder for motorcycle which has an open hole is carried out so as to investigate the boring and hone stone effects on accuracy of honing. As the experimental result of this study we could conclude that it is possible to secure good conditions of honing by controlling and keeping appropriate cycle-time in the stage of boring for the prior step of honing.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.63-70
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• 2008

Conical horn is used in many high frequency ultrasonic horns, to achieve a longitudinal vibration mode across a wide ultrasonic tool horn output surface. Modal analysis is method for designing tuned ultrasonic tool horn and for the prediction natural frequency of ultrasonic tool horn vibration mode. The design of ultrasonic horn is based on prototype estimate obtained by FEM analysis. The FEM simulated ultrasonic tool horn is built and characterized experimentally through laser vibrometer and electrical impedance analysis. In this paper, FEM analysis is developed to predict the natural frequency of ultrasonic tool horn and use of in the optimal design of ultrasonic horn shape.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.5
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• pp.784-789
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• 2012

Ultrasonic Cutting which uses a tuned blade resonant in a longitudinal mode, has been used to cut a range of materials from confectionery, baked products and frozen foods, to wood, bone, foams and composites. The Blade design typically uses finite element analysis, and it could be predicted vibration mode, gain and amplitude uniformity of the blade tip at resonant frequency. In this paper, FEA used to predict the vibration characteristic of the blade, and then the results were verified by analysis system of resonant frequency using the processed blade. The crack of the blade which is predicted from FEA was compared with the crack occurred by cutting experiment of rubber materials using the processed blade.

• Journal of Korean Medical classics
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• v.17 no.4
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• pp.31-36
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• 2004

개요 및 목적: 고금명의(古今名醫)들의 신(神), 혼(魂), 백(魄), 의(意), 지(志) 등의 이상에 대한 치료를 고찰분석(考察分析)함으로서 오장과 신(神), 혼(魂), 백(魄), 의(意), 지(志)의 대응관계를 연구하였다. 방법: 임상병례(臨床病例)들을 취하고 통계방법을 사용하여 고금명의들의 처방 중에서 조건에 부합되는 처방 589예를 선택하여 약물귀경에 대하여 통계처리를 함으로서 각 종류의 정신중상에 사용된 약들이 어느 한 장부계통과 특정적인 대응규칙이 있는지 여부를 분석해 보았다. 결과: 임상치료(臨床治療)에서 여러 가지 정신증상에 사용된 약들은 오장계통에 모두 영향을 주었는데 여러 가지 정신증상을 치료하는 약들은 어떤 한 가지 증상에 그와 대응되는 한 가지 장부 계통이 연관되는 특정적인 규칙은 없었다. 각 종상에 사용된 약들은 오장계통(五臟系統)중에서도 심계통과 비위계통을 치료하는 약이 나타난 빈도가 가장 높았다.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.79-79
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• 2009

Ultrasonic fine welding, cutting, cleaning, inspection and measurement is widely used in various fields over 20kHz. However, for High Frequency of 60kHz or more study areas is still insufficient, and the result is lacking. Therefore, this study used ultrasonic horn to the Bonding of Dissimilar Materials for effective design. Finite element analysis (FEA) is using the equations of motion to establish the model. The optimal design for the basic interpretation of vibration characteristics of the ultrasonic measures horn will examine the design.

• Proceedings of the Korean Institute of Landscape Architecture Conference
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• 2007.10c
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• pp.15-19
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• 2007

본 연구는 서양의 과학적 합리적 이성주의에 대한 단절된 동양문화의 상징적 사유체계에 내재된 상상적 환경을 복원하는 것을 목적으로 하였다. 상상적 환경을 복원하기 위해 한국 중국 일본의 고대도시인 서울, 북경(北京), 교토(京都) 등을 사례대상지로 선정하였다. 이들 사례도시의 역사 문화경관을 분석하여 상상적 환경요소를 도출하고자 해석학과 현상학적 접근방법을 활용하였다. 동북아시아 삼국(한 중 일)의 역사문화경관 비교와 재해석을 통해 그 속에서 내재된 상상적 환경을 도출한 결과, 각 도시에 내재된 장소의 정신과 자연환경요소가 인문환경요소로 반영되어 구조화되었으며, 개별요소들이 결합하여 조직화되었고, 점진적으로 장소(場所)의 혼(魂)은 더욱 성화(聖化)되었다. 본 연구는 인간생활의 실존적(實存的) 장(場)인 도시공간을 상상적 환경이라는 새로운 개념으로 비교분석한 최초의 시도로서 의의를 가진다. 그러나 동북아시아 삼국의 역사문화경관에 내재된 상상적 환경의 보편성을 확인한 것은 의미가 있으나, 각 도시별 세부적인 요소에 이르기까지 특수성을 밝히는 데는 한계가 있었다.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.3
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• pp.113-121
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• 2003

In this paper, the transmit antenna for the space feeder used for the phased array antennas is investigated. The multi-aperture horn antenna is proposed as the transmit antenna and the characteristics are verified with the Matlab coding, HFSS of Ansoft Corp., and MWS of CST Corp., The E-plane and H-plane beam patterns of the multi-aperture horn antenna are nearly symmetrical and the sidelobe level of the I-plane beam pattern is lower than that the of general pyramidal horn antenna. The fabricated multi-aperture horn antenna is measured using the near-field measurement system. The measured results show good agreement with the simulated ones.