• 한국기후변화학회지
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• 제9권3호
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• pp.293-302
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• 2018

This study was carried out to provide basic information on efficient preservation and management of an Abies koreana forest through analyzing the ecological characteristics by slope in Seseok, Mt. Jirisan. Soil moisture content at southern and northern slopes was 29.9% and 21.7%, respectively, and there was no significant difference among soil properties between southern and northern slopes. The importance value of A. koreana in the southern and northern slopes was high for tree and subtree layers, respectively. It is noteworthy that many seedling and saplings of A. koreana were present on the southern slope. The species diversity was 0.413 for the tree layer, 0.632 for the subtree layer, and 0.609 for the shrub layer on the southern slope and 0.396 for the tree layer, 0.783 for the subtree layer, and 1.215 for the shrub layer on the northern slope. Evenness and dominance ranged from 0.371 to 0.609 and 0.629 to 0.391 on the southern slope and from 0.380 to 0.968 and 0.620 to 0.032 on the northern slope, respectively. The mortality of A. koreana was 9.6% on the southern slope and 24.4% on the northern slope, a distinct difference between the slopes. The mortality type at two slopes was the highest proportion of standing dead. Annual mean tree ring growth of A. koreana on the southern slope (1.76 mm/yr) was higher than that on the northern slope (1.64 mm/yr).

• 환경영향평가
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• 제19권3호
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• pp.231-245
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• 2010

The the purpose of this study was to analyze of the vegetation structure and phytosociological changes in the area adjacent to GeumJeong Mountain Fortress for fifteen years. The result of this study was as follows; Of the 8 quadrates, site of the North Gate 2 was having a highest in the number of extinct trees, 15 kinds. This is probably due to trampling effect caused by climbers' steps. Site of the West Gate 1 and South gate 1 each had 8 kinds of extinct trees, respectively. The number of newly appeared trees was highest at site of the North Gate 1, (8 kinds) followed by the sites of South gate 1 and South gate 2, respectively (5 kinds). The highest decrease in number of tree species was observed in North Gate 1, therefore, there is a strong relationship between vegetation diversity and the number of users of the available spaces. In order to revitalize the unstable vegetation structure of the Area Adjacent to GeumJeong Mountain Fortress, Robinia pseudo-acacia has to be well maintained in the shrub tree layer, and vines, such as Smilax china, Humulus japonicus, and Pueraria thungergiana, should be removed. To recover natural vegetation, dead leaf layer should be protected, and more shrub trees need to be planted. In the understory and shrub tree layer, multi layer tree planting is highly recommended to recover natural vegetation and increase tree diversity. In order to improve bad soil condition caused by trampling effect of recreational users, special treatments to the soil structure are required, such as mulching and raking soil. Also, depending on its soil damage from users trampling, the areas in the park should be divided into usable areas and user limited areas by the sabbatical year system. To improve the soil acidity due to acidic rain, soil buffering ability should be improved by activating microorganisms in the soil by using lime and organic material.

• 한국재료학회지
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• 제16권4호
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• pp.248-252
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• 2006

An investigation is reported on the coating of ZnS:Cu,Cl phosphors by $HfO_2$ using atomic layer deposition method. Hafnium oxide films were prepared at the chamber temperature of $280^{\circ}C$ using $Hf[N(CH_3)_2]_4\;and\;O_2$ as precursors and reactant gas, respectively. XPS and ICP-MS analysis showed the surface composition of coated phosphor powder was hafnium oxide. In FE-SEM analysis, the surface morphology of uncoated phosphors became smoother and clearer as the number of ALD cycle increased from 900 to 1800. The photoluminescence intensity for coated phosphors showed $7.3{\sim}13.4%$ higher than that of uncoated. The effect means that the reactive surface is uniformly coated with stable hafnium oxide to reduce the dead surface layer without change of bulk properties and also its absorptance is almost negligible due to ultrathin(nano-scaled) films. The growth rate is about $1.1{\AA}/cycle$.

• The Korean Journal of Ecology
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• 제7권4호
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• pp.185-193
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• 1984

Regneration process of Abies koreana-Pinus koraiensis community consisted of a subalpione coniferous forest in Mt. Jiri, Korea, was studied in relation to age structure, especially to gap formation. The tall-tree layer (ca. 6.5m) is dominated by Abies koreana and Pinus koraiensis, while lower layer by the sapling and juveniles of A. koreana and Picea jezoensis below 2m tall. The ranges of DBH in A. koreana, P. koraiensis and P. jezonesis were 11.8cm~26.4m, 11.7cm~24.5 cm and 18.2cm~21.7 cm, respectively. The trees below 130 cm tall had contagious distribution, while tall and subtall trees had uniform distribution. The average tree ages of A. koreana, P. koraieniensis and P. jezoensis were 60~70 years, 70~80 years and 70~90 years, respectively. The saplings and juveniles below 20 years in tree ages were occupied over 80% of total trees. The coniferous trees in the gaps or around dead trees were composed of sapligs and juveniles which had emerged or invaded about 20 years before and after the gap formation. The Betula type regeneration of the coniferous forest took place in gaps which orginated from the failing down of a single or a few trees by longevity. Accordingly, it is clear that the subalpine coniferous forest composed of A. koreana of A. koreana, P. koraiensis and P. jezoensis in Mt. jiri was supporting by the regeneration pattern of Betula type.

• 한국환경생태학회지
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• 제8권1호
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• pp.58-67
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• 1994

Object of this study is to suggest the plan for natural vegetation restoration and management by ecological approach. The concept of biotope planting technique was introduced in order to restore the natural vegetation in the northern part of Mt. Nam in Seoul, and Quercus mongolica forests was surveyed so as to obtain the basic data. This study focused on the vegetational context between northern part of Mt. Nam and develop-reserved site. The results are following ; 1. It is suitable to plant 25~30 trees in $100\m^2$ with trees of DBH 10cm and below at intervals of about 2m in canopy layer. In the case of subtree layer of DBH 2cm, about 30 trees were planted at an Intervals of 1.5~2m around in $100\m^2$. 2. In the last step of nature vegetation restoration, it is desiable that canopy density is $5/100\m^2$ and 녀btree one is 10~20/$100\m^2$. 3. Management plans was proposed to use the native species of Mt. Nam around and to investigate the ecological situation once a year such as species introduce, dead-tree, soil, fauna etc.

• 한국방사선학회논문지
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• 제9권2호
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• pp.73-77
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• 2015

검출기의 자세한 구조를 알고자 CT 스캐닝을 하였으며 크리스털 형상과 사층에 관한 세부적인 구조를 전산모사 계산법을 이용해 재현하였다. 낮은 에너지의 감마선에 대한 피크 효율이 거리가 작아질수록 감소, 보다 높은 에너지(400 keV) 아상에서의 전체 효율성은 검출기 코어를 조정함으로써 불확도를 줄일 수 있었다. PENELOPE 계산법을 이용해 얻은 공간적 의존성 사이에 적절한 일치점이 달성되었음을 확인 하였다. 이는 크리스털 코어, 모서리와 크리스털 코어의 라운딩을 설명해 주는 매개변수들을 조정함으로써 달성되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.253-253
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• 2013

본 실험에서는 전구체(Precursor)로 TMA (Tris methyl Aluminum)를 사용한 ALD (Atomic Layer Deposition)와 PEALD (Plasma Enhanced Atomic Layer Deposition) 공정 중 발생하는 입자(particle)를 ISPM (In-Situ Particle Mornitor)로 관찰하였다. ALD과 PEALD 공정에서 Al2O3 박막을 형성하기 위해서 반응가스(Reactant)로 각 각 H2O와 O2 plasma를 사용하였다. 이러한 차이로 인해서 진공 챔버(Vacuum Chamber) 안에서의 각기 다른 매커니즘에 의해서 Al2O3의 박막이 형성된다. 또한 공정 중 발생할 수 있는 파티클(Particle) 생성 매커니즘의 차이점을 가진다. ALD의 경우 전구체와 반응가스 사이에 충분한 purge가 이루어지지 않거나 dead zone이 존재할 경우 라인과 챔버 상에 잔류한 전구체와 반응가스에 의해서 불완전한 반응물로 파티클이 생성될 수 있다. 반면 PEALD 경우는 반응가스(Reactant)로 O2 plasma를 극부(localization)적으로 형성하여 박막을 형성하므로 반응가스의 잔류의 영향은 없으나 고에너지의 플라즈마에 의해서 물리적 영향에 의한 파티클이 생성될 수 있다. 공정 중 발생하는 입자(Particle)은 수율 감소와 박막의 물성에 영향을 미칠 수 있다. 그러므로 두 공정 중 발생하는 파티클을 ISPM으로 관찰하였고, 각 공정에서 형성된 박막의 두께 균일도, 표면의 형상(morphology), 화학적 조성 및 전기적 특성을 측정하였다. 이를 통해서 ALD와 PEALD의 파티클과 박막특성을 비교하였다.

• The Korean Journal of Ecology
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• 제19권1호
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• pp.47-53
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• 1996

Effects of group breeding of herons on pine community were studied at Pomaeri, in Yangyang, Kangwon Province, Korea. This site has been protected as a Natural Monument (No. 229) since 1970. Herons have used this habitat as a breeding site from] anuary to October every year. In 1995, more than 500 herons were observed in this habitat. Many big pine trees are dying or already dead due to group inhabitation of herons, and no pine saplings were found at forest floor in this habitat. Nutrient contents of soil in this habitat were much higher than those in control plot. This must be due to the addition of feces from herons and of thin twigs and other organic materials from the canopy and bird nests. Species composition of herb layer in this habitat was quite different from that in control plot. Breeding site was dominated by Humulus japonicus. Persiearia perJohata, Persicaria thunbergii. and Commelina communis. which are indicator species of soil eutrophication.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1228-1229
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• 2011

A novel approach has been promoted for FNN ship controllers. An Electro-hydraulic governor has been widely adopted to the ship speed control of propulsion marine diesel engines for a long time, it was very difficult for Electro-hydraulic governor to regulate the speed of high power engine with long stroke at low speed and low load, because of the jiggling phenomena by rough fluctuation of rotating torque and the hunting phenomena by long dead time occurred in fuel combustion process in the engine cylinder. This paper provides an efficient way for improving control performance by FNN controller. An RBF neural network and GA optimization are employed in a fuzzy neural controller to deal with the nonlinearity, time varying and uncertain factors, the rule base and membership functions can be auto-adjusted by GA optimization. The parameters of neural network can be decreased by using union-rule configuration in the hidden layer of the network. The performance of controller is evaluated by the system simulation using simulink tools.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.392-395
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• 2006

The configuration of coaxial co-rotating contained in shroud provides a useful model for investigating the characteristics of flow in the HDD. Reynolds number is defined as $Re_R={\Omega}{R_o}^2/{\upsilon},\;Re_H={\Omega}R_oH/{\upsilon}$ in present study. An experimental investigation was performed for turbulence profiles and PSD distribution and vortices frequency behavior for various range of $Re_R=2.43{\times}10^4{\sim}3.61{\times}10^5$. A laser Doppler anemometry (LDA) is used to obtain the velocity field of unobstructed co-rotating disks flow. Airflow pattern visualization between inner and outer region was compared with turbulence profiles measured from LDA. Outer detached shear layer and dead-zone without oscillating velocity fluctuation to circumferential mean were quantitively traced.