• 대한기계학회논문집
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• 제9권6호
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• pp.750-756
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• 1985

본 연구에서는 종횡비 0.1이고 상.하 수평경계면이 단열된 직각밀폐용기내에 서 Pr수가 1보다 큰 물(Pr=6.97, 20.deg. C) 및 실리콘 오일(Pr=1086.42, 20.deg. C)의 양단의 온도차에 의한 자연대류에서 아직 충분히 연구되지 않은 코어형상에 주안점을 두고 실 험적으로 관찰, 조사하였으며 그 결과를 Lee의 이론적인 예측과도 비교, 검토해 보았 다.

• 한국해안·해양공학회논문집
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• 제29권6호
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• pp.363-368
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• 2017

지진해일은 그 파랑이 연안 도시로 범람하여 육상 구조물에 피해를 주게 된다. 육상 구조물에 미치는 파압 및 파력에 대한 연구는 육상 구조물의 안정성 설계의 중요한 요인 중 하나이다. 본 연구에서는 단순화한 박스구조물에 미치는 지진 해일의 수평 파력 및 파압에 대한 2차원 단면 수리모형실험을 수행하였다. 시간에 따른 수평 파압의 수직 분포와 파력을 파압계와 파력계를 사용하여 계측하여 상호 비교하였다. 또한, 쇄파의 형태도 다양하게 고려하여 계측하였다. 쇄파된 파랑이 입사하는 경우 구조물에 미치는 수평 파력이 최대가 되는 순간에는 수평 파압이 수직적으로 균일하였고, 그 외의 경우에는 육상 저면에 가까울수록 수평 파압이 커지는 분포를 보였다. 최대 수평 파력을 다양한 입사파랑 조건에 대한 함수로 표현하기 위해 쇄파상사계수를 사용하여 수평 파력과의 관계식을 산출하였다. 그 결과 무차원화한 수평 파력은 쇄파상사계수가 증가함에 따라 지수적으로 감소하는 경향을 있음을 보였다.

• 한국수산과학회지
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• 제42권1호
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• pp.68-72
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• 2009

To gain a greater understanding of the potential for future harmful algal bloom (HAB) outbreaks and to trace the dispersal paths of dinoflagellates, sediment samples were collected from 13 stations in the southeastern Yellow Sea. 23 different types of dinoflagellate resting cysts were identified from the samples. Protoceratium reticulatum (1-391 cells/g dry weight), Gonyaulax scrippsae (0-254 cells/g dry weight), G. spinifera (0-301 cells/g dry weight) and Alexandrium spp. (ellipsoidal type) (0-76 cells/g dry weight) were the dominant species at all surveyed stations. The overall distribution pattern demonstrated that the resting cyst densities were highest in the offshore area and decreased gradually toward the Korean coast. On the other hand, the composition rate of resting cysts of the heterotrophic dinoflagellate species to the total dinoflagellates was higher in the Korean coast region than in the offshore area. We supposed that this distribution pattern of dinoflagellate resting cysts appeared to be influenced by the hydrographic features and environmental conditions of the Yellow Sea.

• 한국도로학회논문집
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• 제15권3호
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• pp.103-115
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• 2013

PURPOSES: The purpose of this study is to develop a method for distribution between superelevation and side friction factor by increasing design speed. METHODS: First of all, a method for distribution between superelevation and side friction factor and a theory for the functional formula of side friction factor in compliance with horizontal radius applied in South Korea and the United States are considered. Especially, design speed of 140km/h and numerical value of design elements are applied to the theory for the functional formula of side friction factor in AASHTO's methods. Also, the anxiety EEG upon running speed is measured to reflect ergonomic characteristics through field experiments at seven curve sections of the West Coast Freeway, and this data is applied to graph for the functional formula of side friction factor. RESULTS : Matching side friction factor against the anxiety EEG, the results that a critical points of driver's anxiety EEG sharply increase locate under existing parabola are figured out. CONCLUSIONS : Therefore, we could get a new type of the functional formula that driver's driving comfortability is guaranteed if the existing the functional formula of side friction factor goes down under boundary of the critical points of the anxiety EEG.

• 조명전기설비학회논문지
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• 제28권8호
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• pp.24-31
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• 2014

This paper dealt with the LED optical illumination system design for the Masthead navigation light to replace halogen lamps. We made Fresnel lens satisfy luminous intensity distribution of "Convention on the International Regulation for Preventing Collisions at Sea(COLREG)". The optical system is designed by classifying three parts: light source, lens, and cut off plate. The source of light has been made to have the uniform horizontal and vertical light distribution by placing 6 LEDs at intervals of $54^{\circ}$, and as the cylindrical Fresnel lens, the lens has been designed to achieve the uniform horizontal and vertical light distribution in the range of plain light. Finally, the cover has been designed to block the light from the outside of plain light and ultimately met the standards for light distribution of navigation lights. In addition, the validity of design has been verified with manufacturing a trial product.

• 전기학회논문지P
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• 제57권2호
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• pp.79-83
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• 2008

In this paper, we introduced a LIF measurement method and summarized the theoretical side. When an altered wavelength of laser and electric power, lamp applied electric power, we measured the relative density of the metastable state in mercury after observing a laser induced fluorescence signal of 404.8nm and 546.2nm, and confirmed the horizontal distribution of plasma density in the discharge lamp. Due to this generation, the extinction of atoms in a metastable state occurred through collision, ionization, and excitation between plasma particles. The density and distribution of the metastable state depended on the energy and density of plasma particles, intensely. This highlights the importance of measuring density distribution in plasma electric discharge mechanism study. The results confirmed the resonance phenomenon regarding the energy level of atoms along a wavelength. change, and also confirmed that the largest fluorescent signal in 436nm, and that the density of atoms in 546.2nm ($6^3S_1{\to}6^3P_2$) were larger than 404.8nm ($6^3S_1{\to}6^3P_2$). According to the increase of lamp applied electric power, plasma density increased, too. When increased with laser electric power, the LIF signal reached a saturation state in more than 2.6mJ. When partial plasma density distribution along a horizontal axis was measured using the laser induced fluorescence method, the density decreased by recombination away from the center.

• Advances in Energy Research
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• 제6권1호
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• pp.35-54
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• 2019

A successful blade design must satisfy some criterions which might be in conflict with maximizing annual energy yield for a specified wind speed distribution. These criterions include maximizing power output, more resistance to fatigue loads, reduction of tip deflection, avoid resonance and minimize weight and cost. These criterions can be satisfied by modifying the geometrical parameters of the blade. This study is dedicated to the aerodynamic assessment of a 20 kW horizontal axis wind turbine operating with two possible airfoils; that is $G{\ddot{o}}ttingen$ 413 and NACA 2415 airfoils (the Gottingen airfoil never been used in wind turbines). For this study parameters such as chord (constant, tapered and elliptic), twist angle (constant and linear) are varied and applied to the two airfoils independently in order to determine the most adequate blade configuration that produce the highest annual energy output. A home built numerical code based on the Blade Element Momentum (BEM) method with both Prandtl tip loss correction and Glauert correction, X-Foil and Weibull distribution is developed in Matlab and validated against available numerical and experimental data. The results of the assessment showed that the NACA 2415 airfoil section with elliptic chord and constant twist angle distributions produced the highest annual energy production.

• 대기
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• 제21권4호
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• pp.391-404
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• 2011

This study investigates the impact of cumulus parameterization scheme (CPS) with different horizontal grid sizes on the simulation of the local heavy rainfall case over the Korean Peninsula. The Weather Research and Forecasting (WRF)-based real-time forecast system of the Joint Center for High-impact Weather and Climate Research (JHWC) is used. Three CPSs are used for sensitivity experiments: the BMJ (Betts-Miller-Janjic), GD (Grell-Devenyi ensemble), and KF (Kain-Fritsch) CPSs. The heavy rainfall case selected in this study is characterized by low-level jet and low-level transport of warm and moist air. In 27-km simulations (DM1), simulated precipitation is overestimated in the experiment with BMJ scheme, and it is underestimated with GD scheme. The experiment with KF scheme shows well-developed precipitation cells in the southern and the central region of the Korean Peninsula, which are similar to the observations. All schemes show wet bias and cold bias in the lower troposphere. The simulated rainfall in 27-km horizontal resolution has influence on rainfall forecast in 9-km horizontal resolution, so the statements on 27-km horizontal resolution can be applied to 9-km horizontal resolution. In the sensitivity experiments of CPS for DM3 (3-km resolution), the experiment with BMJ scheme shows better heavy rainfall forecast than the other experiments. The experiments with CPS in 3-km horizontal resolution improve rainfall forecasts compared to the experiments without CPS, especially in rainfall distribution. The experiments with CPS show lower LCL(Lifted Condensation Level) than those without CPS at the maximum rainfall point, and weaker vertical velocity is simulated in the experiments with CPS compared to the experiments without CPS. It means that CPS suppresses convective instability and influences mainly convective rainfall. Consequently, heavy rainfall simulation with BMJ CPS is better than the other CPSs, and even in 3-km horizontal resolution, CPS should be applied to control convective instability. This conclusion can be generalized by conducting more experiments for a variety of cases over the Korean Peninsula.

• 한국지하수토양환경학회지:지하수토양환경
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• 제13권2호
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• pp.54-61
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• 2008

수평 혹은 경사 형태 특수 정호 양수량에 대한 시공간적 수위 강하를 지하수 수치 모델링을 활용하여, 평가하였다. 지하수 수치 모델링은 상용 프로그램인 FEFLOW(version 5.1)의 1차원 선형 불연속 특징 요소를 활용하여 수행되었으며, 수치해의 검증을 위해 Zhan과 Zlotnik(2002)이 제안한 연속된 점 형태 배출원 배열 방식 준 해석해와 비교하였다. 비교 검증 결과, 수치해와 준해석해는 최대 수위 강하가 나타나는 양수 최인접부를 제외하고는 거의 일치한 형태를 보여주었다. 검증된 수치적 방법을 이용하여, 강변여과 방식 취수가 검토되는 현장에 대한 수위강하를 정량적으로 평가할 수 있었다.

• 유통과학연구
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• 제14권1호
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• pp.39-49
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• 2016

Purpose - Considering industrialization development stages, an economic effect of ASEAN free trade agreement (FTA) on foreign direct investment (FDI) flows into the ASEAN countries was analyzed. Research design, data, and methodology - utilizing macro-level panel data from 2001 to 2012, panel regression analysis was conducted with a model constructed based on the knowledge-capital model. Results - As for overall ASEAN countries, ASEAN FTA was positively effective to attract vertical FDI to this region, while horizontal FDI was dominant before ASEAN FTA. Meanwhile, for the diversified economy relevant to Singapore, ASEAN FTA was not effective to attract FDI. For the ongoing industrialization economy relevant to Thailand, Malaysia, and the Philippines, ASEAN FTA was negatively effective to attract FDI; ASEAN FTA became a strong incentive to replace foreign investments with trade transactions for the horizontal firms, but an influence of market potentials after ASEAN FTA, which induces to third-country effects such as export platform FDI, has increased. For the incipient industrialization economy relevant to Indonesia, Vietnam, and Cambodia, ASEAN FTA was positively effective to attract vertical FDI. Conclusions - The effectiveness of FTA on FDI inflows varied considerably by the industrialization development stages of host countries.