• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1992.08a
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• pp.72-76
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• 1992

평면파 수치모형 해석시 가상경계에 평행한 입사각을 갖거나, 다방향의 입사파가 가상경계로 동시에 입사되는 경우에는 무처리 시 수치 반사가 발생되므로 해에 악영향을 미친다. 따라서 이러한 경우에 대해 가상경계에서 파랑 Energy 투명하게 통과시키는 고차원 무반사 경계조건에 대해 연구하였다. 이들 조건식의 수학적 안정성을 분석하기 위해 phperbolic system에서 normal-mode 분석을 수행하였다. 1차 및 2차의 고차원 무반사 경계조건을 Galerkin 가중잔차법을 이용 유한요소 모형에 적용하였으며 이들에 대한 특성을 시험하기 위해 수치실험을 실시하였다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.35-36
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• 2001

전보의 무부자망은 해상시험 조업의 결과, 망구의 전개 및 중ㆍ저층에서의 예망수층 조절등이 손쉽게 이루어지는 것이 확인되었으나 뜸줄부가 표층 ∼ 30m에서의 예망수심조절이 어렵다는 것이 확인되었다. 따라서, 무부자망은 망구전개가 F.W(Front weight)의 침강력에 의하여 이루어지므로 어구의 예망수심의 깊이 조절이 한계를 받으므로 이것을 극복하기 위하여 카이트(Kite)를 도입하기로 하고 본 연구를 실시하였다. (중략)

• Fire Science and Engineering
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• v.28 no.4
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• pp.57-63
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• 2014

This study was performed to test the combustive properties of Medium Density Fibreboard (MDF) specimens treated with piperazinomethyl-bis-phosphonic acid (PIPEABP), methylpiperazinomethyl-bis-phosphonic acid (MPIPEABP), and N,N-dimethylethylenediaminomethyl-bis-phosphonic acid (MDEDAP). MDF Plates were painted in three times with 15 wt% solution of the alkylenediaminoalkyl-bis-phosphonic acids at the room temperature, respectively. After drying specimen treated with chemicals, combustive properties were examined by the cone calorimeter (ISO 5660-1). It was indicated that the specimens treated with chemicals showed the later time to peak mass loss rate ($TMLR_{peak}$) = (340475) s than that of virgin plate by reducing the burning rate. In adition, the specimens treated with chemicals showed the higher $CO_{mean}$ production (0.0883~0.0963) kg/kg than that of virgin plate. Especially, the specimens treated with chemicals showed the higher mean smoke extinction area ($SEA_{mean}$) ($5m^2/kg{\sim}21.5m^2/kg$) than that of virgin plate. Thus, It is supposed that the combustion-retardation properties were improved by the partial due to the treated alkylenediaminoalkyl-bis-phosphonic acids in the virgin MDF Plate. However, It gave a negative effect on smoke reduction.

• Journal of Aerospace System Engineering
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• v.13 no.1
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• pp.11-17
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• 2019

In this paper, the performance of a small fixed wing unmanned aerial vehicle is predicted theoretically with the minimum specifications and a low Reynolds number. Based on the results, it was compared with the results of an actual flight test and simple electric motor wind tunnel test. As a result of the validity of the analysis, a 3.5 kilograms class fixed wing small UAV can predict aerodynamic performance by general theory analysis. However, the required thrust was analyzed as a possible design error. Based on the results of this study, this paper proposed a method to minimize the design error when developing small fixed wing UAV flying in a low Reynolds number.

• Journal of Aerospace System Engineering
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• v.13 no.2
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• pp.1-9
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• 2019

This paper elaborates on the directional axis guidance and control algorithm used in mission flight for high altitude long endurance UAV. First, the directional axis control algorithm is designed to modify the control variable such that a strong headwind prevents the UAV from moving forward. Similarly, the guidance algorithm is designed to operate the respective algorithms for Fly-over, Fly-by, and Hold for way-point flight. The design outcomes of each guidance and control algorithm were confirmed through nonlinear simulation of high altitude long endurance UAV. Finally, the penultimate purpose of this study was to perform an actual mission flight based on the design results. Consequently, flight tests were used to establish the flight controllability of the designed guidance and control algorithm.

• Journal of the korean veterinary medical association
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• v.45 no.8
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• pp.746-757
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• 2009

국립수의과학검역원과의 공동연구과제(소 아까바네병, 츄잔병, 아이노 바이러스혼합불활화 예방약 산업화)에 의해 실시한 시험을 통하여 소 아까바네병, 츄잔병, 아이노 바이러스병에 대한 예방약인(소 츄잔병, 아까바네병, 아이노병 불활화 혼합오일백신) 면역원성 시험 및 야외에서의 적용시험 등을 실시한 결과를 요약하면 다음과 같다. 1. 혼합오일백신의 기니픽에 대한 면역원성 시험에서 아까바네 바이러스, 아이노 바이러스 및 츄잔 바이러스에 대한 중화항체가는 시험백신을 3주 간격 2회 접종한 시험구가 무접종 대조구에 비하여 높게 나타났다. 2. 혼합오일백신의 야외농장 3곳의 육성우에 대한 면역원성 시험에서 시험백신을 2회 접종 후 아까바네 바이러스의 항체가는 평균 102배, 115배 및 134배이였으며, 아이노 바이러스의 항체가는 평균 8배, 24배 및 27배로 나타났고, 츄잔 바이러스의 경우에는 3곳의 농장에서 평균 30배, 46배 및 172배로 나타났다. 3. 야외농장 2곳에서 혼합오일백신을 임신우에 2회 접종하였을 때, 중화항체가는 아까바네 바이러스가 평균 64배와 93배를 나타내었고, 아이노 바이러스의 중화항체가는 평균 70배와 96배, 츄잔 바이러스의 중화항체가는 평균 20배와 20배로 나타났다. 4. 혼합오일백신은 임신우에 대한 공격접종시험에서 시험백신을 3주 간격으로 2회 접종 후 3주째의 중화항체가는 아까바네 바이러스가 128$\sim$256배이었고, 아이노 바이러스는 64$\sim$256배로 나타났고, 츄잔 바이러스는 8$\sim$32배이었다. 공격 접종 후 부검 전의 중화항체가는 아까바네 바이러스가 16$\sim$128배로 나타났고, 아이노 바이러스는 32$\sim$128배였으며, 츄잔 바이러스는 4$\sim$16배였다. 혼합오일백신을 임신우에 3주 간격 2회 접종한 뒤 공격접종하여 채혈한 혈청의 면역원성이 무접종 대조군에 비하여 방어효과가 우수하였다. 5. 3롯트의 시험백신을 선정하여 2$\sim$7$^{\circ}C$의 냉암소에 보존하면서 보존 기간별(제조당시, 6개월, 12개월, 15개월, 18개월)로 특성시험, 무균시험 및 안전시험을 실시한 결과, 전 보존기간에 마우스 및 기니픽에 대한 안전성이 인정되었으며, 보존기간별로 시험백신의 기니픽에 대한 면역원성 시험을 실시한 결과, 기니픽의 중화항체가는 15개월까지 지속되는 것으로 나타났다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.10
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• pp.955-965
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• 2010

The MH-75 propeller for the MAV propulsion is designed using a free vortex design method which considers design parameters such as the hub-tip ratio, the twist angle distribution, the maximum camber location and the chord length of the propeller blade. Aerodynamic characteristics of the MH-75 propeller are predicted by changing the flight speed using the frequency domain panel method. And, the thrust characteristics of the MH-75 propeller are measured using the balance system of the subsonic wind tunnel for the validation of numerical results. The performance characteristics of the MH-75 propeller satisfied with design requirements. Numerical results of the MH-75, which are predicted by the frequency domain panel method, are more agree with experimental results compare with XFOIL.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.1
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• pp.37-46
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• 2014

This paper describes the conceptual design and development test procedure of a unmanned scaled-down personal air vehicle(PAV) with drive and flight dual mode capability. Trade studies on operational requirements led to the suggestion of a quad tilt prop platform which has nacelle tilt capability with multi rotor configuration. Motors for propeller propulsion and driving mechanism were integrated into a single nacelle, then they were implemented by nacelle tilt mechanism for conversion between the drive and the flight modes. Primary design parameters and initial specifications were confirmed through conceptual design, then functional tests were performed with the test platforms for the drive and the flight modes.

• Korean Journal of Medicinal Crop Science
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• v.3 no.1
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• pp.5-8
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• 1995

This experiment was carried out to obtain the basic information on cultivation of Gentiana scabra BUNGE. Optimum temperature for germination, planting time effect of chemicals on rooting for cutting propagation, effect of cutting on root yield, and content of gentiopicroside were investigated. The germination ratio was highest at $25^{\circ}C$ but lower at $10,\;15,\;20\;,30^{\circ}C.$ The optimum planting time was March 20 the cutting in May and NAA treatment were effective on rooting for cutting propagation. Inhibition of flowering by cutting was effective for increasing root yield but not effective for gentiopicroside content of root.

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.22-31
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• 2013

Flight tests on flight control performance of helicopter, conversion and airplane mode for the Smart UAV were completed. Automatic take-off and landing, automatic return home as well as automatic approach to hover were performed in helicopter mode. Climb/descent, left/right turn using speed and altitude hold mode were performed in each $10^{\circ}$ tilt angle in conversion mode. The rotor speed in airplane mode was reduced to 82% from 98% RPM in order to increase rotor efficiency with reducing Mach number at tip of rotors. It reached to the designed maximum speed, $V_{TAS}$=440 km/h at 3 km altitude. This paper presents the flight test result on full envelopment of Smart UAV. Detailed test plan and test data on control performance were also presented to prove that all data meets the flying qualities requirement.