• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.2
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• pp.129-138
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• 2009

The lunar gravity field is an important source to understand the lunar interior structure, dichotomy and magma ocean of the moon, furthermore it can be used to study the origin and evolution history of the moon. In this paper, we firstly investigated the history of lunar exploration were performed for determining the lunar gravity field, in addition to investigating the procedure of progress related with the lunar gravity field model and gravity observations techniques. After, we determined practically the gravity anomalies of the moon using the new lunar gravity model, SGM90d (SELENE Gravity Model), which were developed by processing the tracking data from SELENE, the japanese lunar mission. Finally, we compared the lunar gravity anomalies from SGM90d model to the those from existing lunar gravity model (LP165P). As results from the comparison, we can make a sense that 4-way Doppler observations of SELENE is very effective to measure the gravity field on the farside of the moon. The precise lunar gravity field model including the farside of the moon which can be more helpful to understand the dichotomy of moon and to establish the detailed distribution of lunar gravity field, such as a mascon.

• The Science & Technology
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• s.497
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• pp.18-22
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• 2010

• Journal of Energy Engineering
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• v.14 no.1
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• pp.30-36
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• 2005

This paper reports the experimental study of the heat transfer characteristics of the wake region behind a cylinder in cross flow. Local heat transfer coefficient was measured from the stagnation point (θ=0°) to 180°, and the variation of Nu in the axial direction along the cylinder was also studied. The results show that the heft transfer rate at the rear (θ=180°) near the duct wall can increase as much as 58% over the 2 dimensional value at the center of the duct. The heat transfer profiles in the wake region also show distinct effects of the aspect ratio and the heat transfer boundary condition.

• Landscaping Tree
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• s.119
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• pp.12-14
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• 2010

제주도, 완도 등 남부해안 지역의 표고 200~700m의 해변과 산록에서 자생하는 상록활엽교목으로 수고 15m, 직경 1m에 달하는 나무로 잎 표면은 녹색의 윤채가 있고, 뒷면은 연한 연갈색의 인모가 있어 관상학적으로 우수한 수종이다. 따라서 남해안 지역에서 가로수 및 정원수로 많은 사랑을 받고 있으며, 병해충에도 비교적 강한 수종으로 알려져 있다. 또한 가을과 겨울에는 혼자만이 꿋꿋이 녹색을 띠면서 적막한 해안도로의 거리를 조금이나마 부드럽고 훈훈하며 따뜻한 느낌을 주는 나무이다. 이러한 구실잣밤나무가 다량으로 식재된 까닭에 최근 구실잣밤나무를 가해하는 해충들이 많이 발생하여 방제에 도움을 주고자 주요해충에 대한 생태 및 방제법을 간략하게 소개하고자 한다.

• Publications of The Korean Astronomical Society
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• v.38 no.2
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• pp.59-73
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• 2023

Since the farside of the moon is a place to avoid artificial radio frequency interference (RFI) created by human civilization, it is a most suitable place for searching technosignature, which are signs of technological civilization in the universe, in the radio band. The RFI is a factor that makes the study of searching technosignature quite complicated because it is difficult to distinguish between technological signals produced by human and extraterrestrial civilizations. In this paper, we review why the farside of the moon is the best place to detect technosignature and also introduce radio observatories on the farside of the moon that have been proposed in radio astronomy. The SETI (Search for Extraterrestrial Intelligence) project on the farside of the moon is expected to be one of the main candidates for international collaboration research topics on lunar surface observatory.

• Korean Journal of Plant Taxonomy
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• v.37 no.4
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• pp.387-393
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• 2007

Saussurea grandicapitulata, a new species of Saussurea, was repodrted in the Taebaek Mountains. It has peculiar morphological characters, easily distinguisable from other Saussurea in Korea and Japan; robust plant size, pale green leaf beneath, purplish brown-cobwebby hairs on petioles of radical and lower cauline leaves, few heads with not so long pedicel, big globose involucres with brown-cobwebby hairs, and often recurved long phyllaries. S. grandicapitula is an endemic species to Korea which was differentiated in consequence of adaptation to heavy snowy environment of the Taebaek Mountains.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.1
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• pp.95-98
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• 2013

Plate thermometers are used for measuring the radiative heat flux in high-temperature surroundings. The heat flux is calculated from the temperature measured at the back surface of the stainless steel surface of the meter. Heat fluxes from a Schmidt-Boelter gauge are measured as reference heat fluxes. A combined conductive coefficient is introduced to consider the heat loss to insulation, conduction through the stainless plate depth, and conduction from the non-uniform temperature of the plate of the plate thermometer. This coefficient is obtained using the repulsive particle swarm optimization.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.603-608
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• 1998

유체내의 물체 주위에서 유동박리로 인해 생성되는 와류쉐딩은 열전달이나 물질전달을 촉진시키는 이점이 있으나, 항력을 증가시키거나 유동 및 온도의 요동에 의해 구조물을 손상시키는 단점이 있다. 특히 물체와 주위 유동 사이에 공진이 일어나면 항력값이 증가하면서 항력과 양력의 진폭이 급격히 증가하여 물체에 심각한 손상을 초래할 수 있다. 본 연구에서는 레이놀즈수 200 이하의 층류유동에서 공진시 물체 주위의 유동현상과 이로 인한 양력과 항력의 변화들을 수치해석방법을 통하여 분석하였다 수치해석은 일반좌표계에서 유한체적법을 적용하여 Navier-Stokes 방정식을 차분화하였다. 이때 방정식의 종속변수로는 공변속도를 채택하였으며, 이산화된 방정식은 분리단계법을 이용하여 수치해를 구하였다. 입구유속의 강제진동에 의한 사각실린더 주위의 와류쉐딩시 공진이 발생하는 강제진동수의 범위는 원통실린더의 경우와 유사하였으나 상대적으로 폭이 더 좁았다 그리고 공진이 발생하는 강제진동수의 범위는 진폭이 증가할수록 증가하였다. 쉐딩 진동수가 일정하면서 입구유속의 진폭이 증가하면 이에 비례하여 실린더 주위의 유속이 상대적으로 증가하게 되어 와도가 강해지면서 입추유속 진폭에 비례하여 항력의 평균값 뿐 아니라 항력과 양력의 진폭도 증가하였다. 그리고 실린더 뒷면의 와류 생성영역은 진폭에 비례하여 감소하였다. 진폭의 변화에 따라 상변화가 서로 상이한 것은 실린더 뒤쪽의 와류들이 상하면의 합력차이를 변화시켰고 이것이 진폭변화에 따라 상변화를 상이하게 나타나게 한 원인으로 진폭이 클수록 실린더 뒤쪽에서 압력변화가 심하게 변하면서 실린더 앞쪽까지 더 많은 영향을 미쳤기 때문이다.선원의 사용자에게 제공되는 최종방사능을 평가하는데 유용하게 사용될 수 있다.r의 분포를 보였다.cting the effect of earthquake on structures. This paper is based on the presented paper at the Bertero Symposium held in January 31an4 February 1 at Berkeley, California, USA which was entitled "Needs to Evaluate Real Seismic Performance of Buildings-Lessons from 1995 Hyogoken-Nambu Earthquake-". The lessons for buildings from the damage due to the Hyogoken-Nambu Earthquake are necessity to develop more rational seismic design codes based upon a performance-based design concept, and to evaluate seismic performance of existing buildings. In my keynote lecture at the Korean Association for Computational Structural Engineering, the history of seismic design and use of structural analysis in Japan, the lessons for buildings from the Hyogoken-Nambu Earthquake, the

• Korean journal of applied entomology
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• v.42 no.2
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• pp.119-124
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• 2003

The adult of the Cotton caterpillar, Palpita indica (Saunder) laid eggs more on mature leaves than on aged and developing leaves. They laid more on leaves than on petiole and stem, and more on the adaxial than on the abaxial surface side of the leaves. Larvae of the Cotton caterpillar showed their preference in the order of the cucumber (Cucumis sativus), gourd (Lagernaria siceraria), watermelon (Citrullus lanatus) ＞ oriental melon (Cucumis melon L. var makuwa), wax gourd (Benincasa hispida), melon (Cucumis melo), star cucumber (Sicyos angulatus) ＞ sponge cucumber (Lufa cylindrica), cotton (Gossypium indicum). There were no distinct differences among varieties and lines that were collected and hybridized at the Gochang Watermelon Experiment Station in Korea. There was a positive relationship between the leaf area and the degree of damage by the Cotton caterpillar. The feeding amounts of the Cotton caterpillar excrement were gradually increased to 16-18 days after hatching, after that the amounts of excrement were rapidly decreased.

• Journal of Bio-Environment Control
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• v.29 no.1
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• pp.73-79
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• 2020

The objective of this study is to analyze the heat transfer loss of covering materials in a single-span plastic greenhouse under the steady-state wind environment. To achieve this objective, the following were conducted: (1) design of a small-scaled wind tunnel (SCWT) to analyze heat losses of the greenhouse and its performance; (2) determination of the overall heat transfer coefficient (OHTC) for the covering materials using a small-scaled greenhouse model. The SCWT consists of the blowing, dispersion, steady flow, reduction and testing areas. Each part of the SCWT was customized and designed to maintain air flow at steady state and to minimize the variances in the SCWT test. In this study, the OHTCs of the covering materials were calculated by separating each with the roof, side wall, front and back of the small-scaled greenhouse model. The results of this study show that the OHTC of the roof increases as wind speed increases but the zones in which the increase rate of the OHTC decreased, were distinguished by wind tunnel wing speed of 2 ms^-1. For the side wall, the increase rate of the OHTC was particularly higher in the 0-1 ms^-1 zone.