• 한국작물학회지
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• 제28권2호
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• pp.272-279
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• 1983

초지군락에서 광이용과 건물생산특성을 알아보기 위하여 오차드그라스, 라디노클로버의 각 단파초지와 오차드-라디노혼파초지, 화본료ㆍ두료의 다혼파초지에 동일한 예취관리를 하고 재생기 1-2주 간격으로 초지구조와 백사광의 투과, 초지의 생장율을 조사한 결과는 다음과 같다. 1) 각초지는 예취후 6주경에 최대의 초형을 이루었고, 오차드그라스 단파구는 직립형, 라디노클로버는 역삼각형, 오차드-라디노혼파구는 중하부에 고르게 분포되었으며, 다혼라구는 초고가 높고 상하에 고른 엽의 분포를 나타내었다. 2) 봄 재생기동안 엽면적지수(LAI)는 다혼파구에서 높았으나 엽면적밀도(L$_{v}$ )는 라디노클로버가 다혼파구보다 더 높아 엽의 밀집화가 심하였고, 가을재생기에는 LAI가 오차드그라스 단파구와 오차드-라디노혼파구에서 높았고, L$_{v}$ 역시 이들 구에서 높았다. 3) 각 초지의 광소멸계수는 오차드그라스단파구가 0.29-0.43으로 라디노클로버단파는 0.70-0.74, 그리고 오차드-라디노혼파구 및 다혼파구는 0.43-0.58을 나타내어 각각 직립엽형, 수평엽형 및 중간엽형으로 특징 지울 수 있었다. 4) 건물수량은 LAI와 높은 정의 상관을 보였고, 한계 LAI는 오차드그라스단파구가 가장 높았고, 라디노클로버단파구가 가장 낮았다. 한편, 적정 LAI는 오차드그라스단파구는 6이상, 라디노클로버 단파구는 3.8, 오차드-라디노혼파구는 5.0, 그리고 다혼파구는 8.0정도이었다. 5) 각 초지의 생장속도는 오차드그라스는 가을재생기에 높았으며, 다혼파구는 가을보다 봄에 현저히 높았으나 라디노클로버는 계절간 차이가 없었다. 6) 다혼파구 및 오차드-라디노혼파구가 초형구조가 양호하였고, 광이용이 향상되었다.

• Journal of Plant Biology
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• 제33권3호
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• pp.173-182
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• 1990

To investigate the structure of the plant community structure of Mt. Yongmun in Kyonggi-do, fifty-four plots were set up by the clumped sampling method. The classification by TWINSPAN and DCA ordination were applied to the study area in order to classify them into several groups based on woody plant and environmental variables. By both techniques, the plant community were divided into two groups by the aspect. the dominant species of south aspect were Pinus densiflora, Quercus aliena, Q. mongolica, Carpinus laxiflora and of north aspect were Q. ongolica, Fraxinus rhynchophylla. The successional trends of tree species in south aspect seem to be from P. densiflora through Q. serrata, Q. aliena, A. mongolica to C. laxiflora. As a result of the analysis for the relationship between the stand scores of DCA and environmental variables, they had a tendency to increase significantly from the P. densiflora and Q. mongolica community to C. laxiflora and F. rhynchophylla community that was the soil moisture, the amount of soil humus and soil pH.

• 대한기계학회논문집
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• 제18권2호
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• pp.251-259
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• 1994

Nearfield acoustic holography is known as a powerful tool to study sound radiation from a structure. In this work, the so called backward propagation of sound pressure field is studied to obtain the structure velocity distribution. The results, which were obtained using FFT algorithms, are presented for a finite plate excited at the frequencies above and below coincidence. These results illustrate the effect of stand-off distance and noise. An optimum cutoff frequency in wavenumber domain was suggested to reduce the effects of evanescent wave in the backward propagation. The experimental results were also included for a plate to demonstrate the effectiveness of the suggested cutoff frequency. The optimum cutoff frequency to exclude the unwanted noise in the process of reconstruction of the velocity field gives the good results in both simulations and experiments.

• 동굴
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• 제4호
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• pp.23-32
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• 1996

The geographic environment means the general state of the environment in the area. Especially, which means the generation cause, the development process of the cave, and the validity of cave development and conservation in the side of the place of the cave. This study put emphasis on lying in which place Hwaam cave in Tong-myon, Chong son-gun, Kangwondo is situated and having in which stand is in comparison with other districts, and how the geological structure which determine the cave forming cause is.(omitted)

• 한국산림과학회지
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• 제90권1호
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• pp.43-54
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• 2001

집단의 유전적 분화는 환경요인과 유전적 소인의 복잡한 상호관계에 의해 이루어지는데, 집단내 요인으로는 종자나 화분 비산, 국소환경변이, 개체의 분포밀도 등을 들 수 있다. 점봉산의 잣나무 임분내 개체 분포와 유전적 구성에 대한 분석을 위하여 신갈나무군락내 잣나무 우접임분에 $100{\times}100m$ 조사구를 설정하였으며, 잣나무 325개체에 대한 동위효소 분석을 실시하고, 공간의 자기상관성을 계산하였다. 11개 동위효소 유전자좌에서 관찰된 평균 다형성 유전자좌 비율(P)은 72.7%, 이형접합도의 관찰치(Ho)는 0.200, 기대치(He)는 0.251로 이형접합체 과소현상을 나타내어 근연가계의 개체들이 다수 분포하는 것으로 조사되었다. 동위효소의 유전자형에 따라 325개체는 총 147 개의 그룹으로 구분되었으며, 한 개 유전자형에 최대 34개체가 포함되었다. 동위효소 유전자형의 이성성이 24~32m 구간(거리간격 8m)을 기점으로 증가하는 양상을 보였으며, 생장특성(수고와 직경)에 대한 simple block distance도 24~32m 구간에서 임의분포를 보였다. 높은 근연교배의 고정계수(F=0.204), 유전적 자기상관성, 생장특성의 분석, 동일 유전자형의 분포범위 등을 고려할 때 점봉산 잣나무 임분은 화분비산이나 숲틈 형성에 따른 종자의 집중 투입에 따른 유전자 이동(gene flow)보다는 유전적 근연(近緣)개체의 밀도(密度)에 의존(density dependent)해서 유전적 구조를 유지하는 것으로 생각되며, 유전적 동질성을 갖는 군락의 크기는 24~32m에서 결정할 수 있었다. 본 연구의 결과 유전자원보존을 위한 개체의 선정은 최소한 37m 이상의 거리를 띄어야 바람직한 것으로 조사되었다.

• Journal of Ecology and Environment
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• 제35권3호
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• pp.213-225
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• 2012

Sap flux density (SFD) measurements were used, in combination with morphological characteristics of trees and forest structure, to calculate whole-tree transpiration, stand transpiration (St) and mean canopy stomatal conductance (Gs). Analysis based on the relationships between the morphological characteristics of trees and whole tree water use, and on the responses of SFD and Gs to short wave radiation (RR), vapor pressure deficit (VPD) and soil water content (SWC) during drought and non-drought periods were conducted. The results showed a strong positive correlation between whole tree transpiration and both tree diameter at breast height (DBH) ($r^2$ = 0.95, P < 0.05) and sapwood area (SA) ($r^2$ = 0.98, P < 0.05). Relationships between SFD and DBH ($r^2$ = 0.25), as well as SA ($r^2$ = 0.17) were weak. Daily SFD of Quercus serrata Thunb was closely related to VPD and RR. Although operating at different time scales, RR and VPD were important interacting environmental controls of tree water use. SFD increased with increasing VPD (<1 kPa) and RR. SWC had a considerable effect on stand transpiration during the drought period. The relationships between SFD, VPD and RR were distorted when SWC dropped below 35%.

• Journal of Forest and Environmental Science
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• 제29권3호
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• pp.219-225
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• 2013

The correlation between disturbance intensity and stand development was evaluated on the basis of natural forest community type classification in areas of Baekhaksan (more disturbed area) and Hwangaksan (less disturbed area). The vegetation data were collected by point-centered quarter sampling method, and they were subjected to cluster analysis for classifying community types and to analysis of species composition and species diversity for reviewing ecological characteristics. By the method of cluster analysis, natural forests of Baekhaksan were classified into Quercus forest community, Pinus densiflora community, Q. variabilis community, and Q. mongolica community. Those of Hwangaksan were divided into P. densiflora community, Q. mongolica community, Q. forest community, and Mixed mesophytic community. It is presumed that more developed and less disturbed forest area shows multiple species community pattern and more diversified structure than less developed and more disturbed forest area. In Korean peninsula, the abundance of red pine may play an important indicator to estimate the developmental pattern of the forest after artificial disturbance. The overall evaluation indicated that less disturbed Hwangaksan area had more developed stand pattern with mixed mesophytic community, more complicated species composition, and higher species diversity than Baekhaksan area.

• Journal of Mechanical Science and Technology
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• 제18권7호
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• pp.1062-1073
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• 2004

We describe a looper controller design for a hot strip finishing mill in steel plants. The main function of the looper system is to balance the mass flow of the strip by accumulating material in the middle of the stands. Another function is to control the strip tension which influences the width of the strip. To ensure strip quality, it is very important to control the tension of the hot strip finishing mill. However, because there is a mutual interaction between the looper angle and the strip tension, it is difficult to control the looper system. Previous researches examined only the operation of a single stand. But it is not sufficient to examine the operation and effect of whole stands because the operation is wholly interdependent. In this paper, we present a full model of the hot strip finishing mill in order to more effectively control strip tension. We propose several control methods for the full-stand hot strip finishing mill, denoted as conventional PI, PI with cross gain, and coefficient diagram method (CDM) PID control. In the real plants, there are some problems by using higher order controllers such as LQ, LQG and H$\_$$\infty$/. By comparison, the PID controller is very simple and easy to apply to all real plants. To that end, we present our findings on PID controls and their potential use in the hot strip finishing mill.

• 헤리티지:역사와 과학
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• 제45권2호
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• pp.4-19
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• 2012

개성과 강화에는 다수의 고려왕릉이 남아 있다. 이 왕릉들은 전대의 능제적 전통을 이어받아 고려만의 독창적인 능제를 완성, 조선왕릉에 전승시켰다. 고려왕릉의 일반적인 특징은 우선 능역을 3~4단으로 구획하고 능제에 맞추어 각 단에 석물과 정자각을 배치하였다. 석실은 입구를 남쪽에 두고 있으며, 벽석은 수직으로 쌓아올렸고, 천장은 평천장이다. 석실바닥에는 중앙에 관대를 놓고, 그 주변에 전돌을 깔았다. 벽면과 천장에는 회칠을 하고 그림을 그렸다. 그런데 석실내부의 구조를 자세히 살펴보면, 이런 일반적인 특징 외에 몇 가지 세부적인 차이가 발견된다. 고려초기에는 1단 평행고임천장과 통돌관대, 유물부장대 그리고 식물소재의 벽화가 조합되어 나타나며, 이는 과도기적 형태를 거쳐 12세기후반을 기점으로 평천장, 장대석재벽석, 석주형석재조립관대로 변하고 있음을 알 수 있다. 한편, 몇몇 왕릉은 출토된 시책(諡冊) 편을 통해 능주를 명확히 규정할 수 있으며, 석실내부에서 출토된 청자는 해당 왕릉의 축조연대와 상당한 시기차가 있음을 확인할 수 있었다. 이점은 도굴 등 왕릉의 파괴로 인한 후대 보수과정에서 당대 유물이 매납된 것으로 판단된다. 마지막으로 기록상 왕릉의 장지방향과 발굴결과를 비교검토하여 능주가 누구인지를 추적해 보았다. 그 결과 충목왕명릉 등 일부 왕릉은 능주의 비정이 잘못되었음을 확인할 수 있었다.

• The Korean Journal of Ecology
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• 제24권6호
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• pp.341-348
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• 2001

Population dynamics of the oldest relic stand of Pinus densiflora for. erecta which remains as a status of patch in Sokwang-Ri area, Uljin-Gun, was studied to provide the basic data for conservation of the oldest pine stand in Korea. The upper slope site and ridge site including total 12 plots mainly represented Pinus densiflora for. erecta and Quercus mongolica. These two tree species showed reverse J-shaped distribution. From this information, it was concluded that intensive interspecific competition between two species could be occurring. Age distribution of P. densiflora for. erecta on the sites above middle slope area was indicated bi-modal type or tri-modal type which was known as an age structure of climax forest. Therefore, it was estimated that Pinus densiflora for. erecta population could be continuously maintained in the each patch above middle slope area. In the valley sites, hardwood species such as Q. mongolica, Q. variabilis, Styrax obassia and Acer pseudosieboldianum occupied most part of the under crown-cover area and their seedlings and saplings were developing into the closed upper layer crown because the height of upper layer crown reached about 35 meters and such a high crown height was more suitable for light utilization by plants of under layer. The growth patterns were mainly fluctuated for the entire life time of the oldest tree caused by frequent disturbance. And the initial growth curves of the mature trees and suppressed juvenile trees showed different tendencies along the sites.