• Journal of Forest and Environmental Science
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• 제33권1호
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• pp.74-77
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• 2017

The purpose of this study is to analyze the effect of thinning intensity on the growth of large diameter trees in Korean white pine (Pinus koraiensis S. et Z.) plantation. Eight thinning plots were analyzed by categorizing into heavy thinning, light thinning, no thinning (control) according to thinning intensity. As a result, average DBH increased more in heavy thinning plots than in light thinning or unthinned plots. The number of large trees (DBH>25 cm) were obviously shown the most in heavy thinning plots. It is considered that heavy thinning is needed for the production of the large diameter trees.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.153-156
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• 2008

Comparative analysis of forest fire danger rating on the forest characteristics of thinning area and non-thinning area on forest fire burnt area was studied in this work. To investigate the effect of thinning slash in forest fire, Gangneung-si Wangsan-myeon, Ulgin-gun Wonnam-Myeon, Samchok-si Gagok-Myeon, in which forest fire broke out, were selected. As a result that investigated forest fire danger ratio between thinning slash and non-thinning slash, leeward scorching ratio(36%), crown damage ratio(29%), mortality of branch at the former are higher than those at the latter, leeward scorching ratio of tree, where thinning slash is around, is 10%-20% higher than that of independent tree. So I estimate that thinning slash has a some effect on the intensity of forest fire. And the result to investigate damage of forest fire according to tree species shows that leeward scorching ratio of conifer is 5% higher than that of non-conifer, and mortality of branch of the former is 19% higher than that of the latter. It is considered that forest fire may affect directly to a tree trunk if it diffuse to piled thinning tree because there was no space between thinning trees and trees. Furthermore, it was found that re-ignition had a chance to occur due to lots of piled thinning trees.

• 생물환경조절학회지
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• 제19권4호
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• pp.392-396
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• 2010

본 연구는 하이부쉬 블루베리(Vaccinium corymbosum) 'Jersey' 품종을 이용하여 적방 1/3, 적방 1/3 +적화 1/2, 적방 2/3 및 적방 2/3 + 적화 1/2처리 후 무처리 과실의 수확량과 과실 품질을 조사하여 적방 적화 정도에 따른 수량과 과실 크기, 가용성당함량, 산함량, 과실 경도를 분석하였다. 적방 적화 처리는 과립중, 종경 및 횡경에 유의한 과립 비대효과를 가져왔다. 과실 수확량은 무처리와 적방 1/3 처리구에서 가장 높았으며, 그 이외의 처리에서는 과립비대는 이루어졌으나 수확량의 감소가 발생하였다. 무처리와 적방 1/3 처리의 경우 전체 수확량은 비슷하였으나, 적방 1/3 처리구에서는 상품성이 큰 대립의 과실이 차지하는 비율이 무처리에 비해서 큰 것으로 조사되었다. 가용성당함량은 적방과 적화 처리에 따라 수량이 감소한 적방 2/3, 적방 2/3 + 적화 1/2 처리구에서 유의하게 증가하였으나, 산함량과 경도에는 영향을 미치지 않았다. 적방 적화에 따른 영향은 과립 비대와 수량에 유의한 차이를 주었으나 과실품질에는 크게 영향을 미치지 않는 것으로 조사되었다.

• Nuclear Engineering and Technology
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• 제52권9호
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• pp.2119-2129
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• 2020

Flow-accelerated corrosion (FAC), liquid droplet impingement erosion (LDIE), cavitation and flashing can cause continuous wall-thinning in nuclear secondary pipes. In order to prevent pipe rupture events resulting from the wall-thinning, most NPPs (nuclear power plants) implement their management programs, which include periodic thickness inspection using UT (ultrasonic test). Meanwhile, it is well known in field experiences that the thickness measurement errors (or deviations) are often comparable with the amount of thickness reduction. Because of these errors, it is difficult to estimate wall-thinning exactly whether the significant thinning has occurred in the inspected components or not. In the previous study, the authors presented an approximate estimation procedure as the first step for thickness measurement deviations at each inspected component and the statistical & quantitative characteristics of the measurement deviations using plant experience data. In this study, statistical significance was quantified for the current methods used for wall-thinning determination. Also, the authors proposed new estimation procedures for determining local wall-thinning to overcome the weakness of the current methods, in which the proposed procedure is based on analysis of variance (ANOVA) method using subgrouping of measured thinning values at all measurement grids. The new procedures were also quantified for their statistical significance. As the results, it is confirmed that the new methods have better estimation confidence than the methods having used until now.

• Journal of Forest and Environmental Science
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• 제36권1호
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• pp.17-24
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• 2020

This study aimed to figure out and compare the increment of biomass by thinning intensity focused on the plantation of the two major coniferous species (Larix kaempferi and Pinus koraiensis) of South Korea. The inventory interval was three years under the effects of three types of thinning treatments; control (no thinning), light (20% thinning) and heavy (40% thinning). The results showed standing biomass increment of both species decreased as thinning intensity increased (heavylight>control). Meanwhile, the lowest of on-site biomass changes occurred in the control plot, and the greatest was in the heavy thinning plot because thinning was involved with leaving the felling residual biomass (leaves, branches and roots) on the site. According to the results from this short-term study, unthinned stands is preferable for maximizing standing biomass as well as carbon sequestration. However long-term investigation should be considered in order to see more clear results.

• 한국안전학회지
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• 제21권6호
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• pp.14-19
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• 2006

This study performed burst tests using real-scale pipe elbow containing simulated local wall-thinning to evaluate the effects of circumferential thinning angle and bending load on the failure pressure of wall-thinned elbow. The tests were carried out under the loading conditions of internal pressure and combined internal pressure and bending loads. Three circumferential thinning angles, ${\theta}/{\Pi}=0.125,\;0.25,\;0.5$, and different thinning locations, intrados and extrados, were considered. The test results showed that the failure pressure of wall-thinned elbow decreased with increasing circumferential thinning angle for both thinning locations. This tendency is different from that observed in the wall-thinned straight pipe. Also, the failure pressure of intrados wall-thinned elbow was higher than that of extrados wall-thinned elbow with the same thinning depth and equivalent thinning length. In addition, the effect of bending moment on the failure pressure was not obvious.

• 대한기계학회논문집A
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• 제27권8호
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• pp.1295-1302
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• 2003

In order to evaluate a failure behavior of pipe with notch-type wall thinning, the present study performed full-scale pipe tests using the 102mm, Schedule 80 pipe specimen simulated notch- and circular-type thinning defects. The pipe tests were conducted under the conditions of both monotonic and cyclic bending moment at a constant internal pressure of 10 MPa. From the results. of experiment the failure mode, load carrying capacity, deformation ability, and fatigue life of a notch-type wall thinned pipe were investigated, and they were compared with those of a circular-type wall thinned pipe. The failure mode of notched pipe was similar to that of circular-type thinned pipe under the monotonic bending load. Under the cyclic bending load, however, the mode was clearly distinguished with variation in the shape of wall thinning. The load carrying capacity of a pipe containing notch-type wall thinning was about the same or slightly lower than that of a pipe containing circular-type wall thinning when the thinning area was subjected to tensile stress, whereas it was higher than that of a pipe containing circular-type thinning defect when the thinning area was subjected to compressive stress. On the other hand, the deformation ability and fatigue life of a notch-type wall thinned pipe was lower than those of a circular-type wall thinned pipe.

• Journal of the Korean Wood Science and Technology
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• 제42권4호
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• pp.385-392
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• 2014

우리나라의 중요한 조림 수종 중에서 낙엽송을 대상으로 하여, 간벌실시에 따른 물리 역학적 성질을 비교 평가함으로써 간벌 실시가 목재의 재질에 미치는 영향과 양질재 생산 및 목재의 효율적 이용을 위한 연구결과는 다음과 같다. 간벌정도에 따른 시료는 무간벌, 약도간벌, 강도간벌을 실시한 광릉시험림에서 벌채하여 사용하였다. 간벌 정도에 따른 평균 만재율은 무간벌 < 약도간벌 < 강도간벌의 경향이었고 평균 연륜폭은 무간벌 < 약도간벌 또는 강도간벌의 경향이었다. 간벌 정도에 따른 평균 휨강도는 무간벌 > 약도간벌 >강도간벌의 경향이었고 간벌 정도에 따른 평균 압축강도는 무간벌 > 약도간벌 >강도간벌의 경향이었다. 이러한 결과로 낙엽송은 간벌에 의하여 휨 및 종압축강도가 감소하는 경향이었다.

• 한국산림과학회지
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• 제100권2호
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• pp.165-171
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• 2011

소나무재선충병 방제법 중 임업적 방제법을 개발하기 위한 일환으로 위생간벌, 간벌, 어린소나무 가꾸기가 소나무재선충병의 제어에 미치는 영향을 구명하기 위하여 야외 그물망 케이지에 소나무재선충을 보유한 솔수염하늘소를 방사하였다. 대조구, 위생간벌, 간벌 처리구 모두에서 공시목의 50% 이상이 고사되었으며, 처리구 간에는 유의성이 나타나지 않았다. 그리고 처리구 내 방치한 숲가꾸기 산물이 소나무재선충병을 확산시키는 촉매제로 작용하였다. 어린 소나무림 가꾸기의 경우 산물을 방치한 처리구가 공시목의 고사율이 90% 이상으로 가장 높았으며, 산물을 케이지 밖으로 들어낸 처리구와 숲가꾸기를 하지 않고 솔수염하늘소의 성충을 방사한 처리구에서는 10% 내외의 고사율을 나타내었다. 솔수염하늘소 우화 당년도인 4월에 위생간벌, 간벌을 실행한 장령목의 벌근에서는 솔수염하늘소의 유충이 출현하지 않았으나, 솔수염하늘소의 우화 당년도인 5월에 숲가꾸기 한 어린나무의 벌근에서는 유충이 출현하였다. 본 실험 결과, 장령 소나무림과 어린소나무림 내에 소나무재선충병이 만연하고 있는 임분의 경우 솔수염하늘소의 우화 당년도인 4월과 5월에 실행한 숲가꾸기는 소나무재선충병의 제어에 아무런 효과가 없었으며 방치한 숲가꾸기 산물은 오히려 소나무 재선충병을 확산시키는 촉매제로 작용하였다.

• Journal of Ecology and Environment
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• 제40권1호
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• pp.5-11
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• 2016

Background: As the decomposition of lignocellulosic compounds is a rate-limiting stage in the nutrient mineralization from organic matters, elucidation of the changes in soil enzyme activity can provide insight into the nutrient dynamics and ecosystem functioning. The current study aimed to assess the effect of thinning intensities on soil conditions. Un-thinned control, 20 % thinning, and 30 % thinning treatments were applied to a Larix kaempferi forest, and total carbon and nitrogen, total carbon to total nitrogen ratio, extractable nutrients (inorganic nitrogen, phosphorus, calcium, magnesium, potassium), and enzyme activities (acid phosphatase, ${\beta}$-glucosidase, ${\beta}$-xylosidase, ${\beta}$-glucosaminidase) were investigated. Results: Total carbon and nitrogen concentrations were significantly increased in the 30 % thinning treatment, whereas both the 20 and 30 % thinning treatments did not change total carbon to total nitrogen ratio. Inorganic nitrogen and extractable calcium and magnesium concentrations were significantly increased in the 20 % thinning treatment; however, no significant changes were found for extractable phosphorus and potassium concentrations either in the 20 or the 30 % thinning treatment. However, the applied thinning intensities had no significant influences on acid phosphatase, ${\beta}$-glucosidase, ${\beta}$-xylosidase, and ${\beta}$-glucosaminidase activities. Conclusions: These results indicated that thinning can elevate soil organic matter quantity and nutrient availability, and different thinning intensities may affect extractable soil nutrients inconsistently. The results also demonstrated that such inconsistent patterns in extractable nutrient concentrations after thinning might not be fully explained by the shifts in the enzyme-mediated nutrient mineralization.