• Title/Summary/Keyword: 천이계열

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Effects of Nitrogen Addition on Thermal Stability of Ta-Al Alloy Films (Ta-Al 합금박막의 열적안정성에 미치는 질소첨가 효과)

  • Jo, Won-Gi;Kim, Tae-Yeong;Gang, Nam-Seok;Kim, Ju-Han;An, Dong-Hun
    • Korean Journal of Materials Research
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    • v.7 no.10
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    • pp.877-883
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    • 1997
  • Ar 및 Ar과 $N_{2}$ 분위기하에서 rf 마그네트론 스퍼터링방법으로 Ta-AI과 Ta-AI-N합금막을 제조하였다. Ta-7.9at.% AI계열, Ta-26.7 at% AI게열과 Ta-45.4at.%AI계열에 Ar에 대한 질서유량비로 26%까지 질소를 첨가하여 Ta-AI-N박막을 증착한후, 300-$600^{\circ}C$온도 구산에서 열처리 전후의 구조 및 전기적 특성과 열적안정성을 통하여 레지스터의 적용가능성을 조사하였다. 구조 및 조성 분석은 X-선 회절과 Rutherford Backscattering Spectrometry(RBS)로 관찰하였고 열적안정성은 4단자법(four point probe method)을 이용한 저항변화를 통하여 측정하였다. 순수 Ta에 AI을 첨가하면 확장된 $\beta$($\beta$-Ta)N 합금박막에서 가장 열적안정성이 우수하게 나타났던 질소첨가 범위는 Ta $N_{hcp}$또는 TaN/ sub fcc/또는 Ta $N_{fcc}$와 비정질과의 혼합상순으로 상천이를 나타내었다. Ta-AI-N 합금박막에서 가장 열적안정성이 우수하게 나타났던 질서첨가 범위는 Ta-26.7at. % AI계열의 경우 19-36at.% $N_{2}$구간이었고, Ta-45.5at.% AI계열의 경우는 30-45at.%구간이었다. Ta-AI합금박막은 질소가 첨가되지 않아도 열처리 온도 및 시간에 따라 약 10% 이내의 비교적 작은 저항변화를 보여 열적안정성이 우수하지만 질소를 첨가하여 Ta-AI-N합금박막을 형성시킬경우, 증착된 상태에서 이미 큰 비저항을 나타내었고 열처리 동안 3%이내의 매우 작은 저항변화를 나타내었기 때문에 레지스터용 재료로써 열적안정성에 대한 잠재력이 크다.

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A Study on the Change of the Plant Community Structure for Five years in Puk′ansan National Park (북한산 국립공원 삼림군집구조의 5년간 변화 연구)

  • 최송현;이경재
    • Korean Journal of Environment and Ecology
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    • v.7 no.1
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    • pp.35-48
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    • 1993
  • To compare ecological succession stage between 1987 and 1992, this study was executed in Mt. Puk'an. 26 sample plots of 500$m^2$ were set up. The results were summarized as follows; 1. To analysis plant community structure, the classification by TWINSPAN and CCA, DCA and RA ordination were applied to the study area. That of Mt. Puk'an was divided 4 groups by altitude. The dividing groups are Robinia pseudo-acacia-Quercus spp. community, mixed forest community, Q. serrata community, and Q. mongolica community. The successional trends of tree species over 500m seem to be from Pinus densiflora to Q. mongolica and below 500m in altitude seem to be from Robinia pseudo-acacia through Quercus acutissima, Q. mongolica, Prunus sargentii, Sorbus alnifolia to Q. serrata in the canopy layer. In the case of understory and shrub layer, the successional trends to be from Corylus sieboldiana, Zanthoxylum schinifolium through Rhus trichocarpa, Rhododendron mucronulatum, Rh. schlippenbachii to Acer pseudo-sieboldianum. 2. In comparing successional trends with 1987', the advanced data was not obtained in 1992. It was postulated that succession is not progressed by human disturbance and air pollution.

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The Structural and Dynamic Analysis of the Forest in Mt. Bomun (보문산 삼림(森林) 군집(群集)의 구조(構造)와 동태(動態) 분석(分析))

  • Kim, Chi Moon;Song, Ho Kyung
    • Korean Journal of Agricultural Science
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    • v.9 no.2
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    • pp.494-506
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    • 1982
  • The community structure and dynamic succession of forest were determinated on the quadrat plots selected randomly at the Mt. Bomun. The plot size was $20{\times}20m$, and analysis of vegetation and soil 'data we re adapted reciprocal averaging(RA) ordination method. 1. The numbers of tree species were twenty, and dominant species were Quercus variabilis, Pinus densiflora, Alnus hirsuta, and Pinus rigida. 2. The forest of Mt. Bomun was found to be composed of Pinus rigida community and Quercus-Pinus community through RA ordination method. 3. The community of Quercus variabilis was assumed to be dominant in the succession of forest. 4. The soil factors, such as total-N, $NO_3$, $NH_4^+$, $P_2O_5$, organic matter, C. E. C., pH, $K^+$, $Ca^{{+}{+}}$ and $Mg^{{+}{+}}$, were analyzed. Total-N, $NO_3^-$, $NH_4^+$, and $P_2O_5$ were assumed to be the main factors of the soil.

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안동 임하댐 일대의 삼림식생에 대한 군락생태학적 연구

  • 송종석;김헌규
    • The Korean Journal of Ecology
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    • v.16 no.4
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    • pp.439-457
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    • 1993
  • The present study was undertaken to classify and describe the forest vegetation on Imha-dam area, located at the northern part of Kyungsang-pookdo, Korea by the phytosociological method of the Z-M school. The field investigations were carried out in 60 plots around the dam area from May 1, 1991 to October 10, 1992. The vegetation data obtained were classified by the table comparison method. As a result, the following vegetation units were recognized: A. Pinus densiflova community A-a. Miscanthus sinensis group A-b. Carex humilzs group A-c. Typical group B. Quercetum variabili-serratae Kobayashi, Muranaga et Takeda 1976 C. Robinin pseudo-acacia-Conzmeli~ta comnzultis community D. Larix leptolepis community The vascular plant species of these forest communities consist of 63 families, 144 genera, 191 species and 30 varieties. Also the relationship of the vegetation units with their environments such as altitude, slope, topography and soil condition was discussed here. On the basis of the floristic composition, life-form spectrum and soil analysis, a sere for the forest vegetation was proposed as follows: Rohinia pseitdo-acacia-Conz~neli~za communis community and Larix leptolepis community $\rightarrow$ Pinus densiflora community $\rightarrow$ Quercetunz variahili-serratae $\rightarrow$ Quercus mongolica community. Lastly, relating to the nature conservation of dam area, some of plans were discussed.

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The Analysis of the Forest Community Structure of Chuwangsan National Park - Case Study of Ijontong Cholto - (주왕산국립공원 삼림군집구조분석 - 이전동 절터지역을 중심으로 -)

  • Lee, Kyung-Jae;Choi, Song-Hyun;Cho, Woo
    • Korean Journal of Environment and Ecology
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    • v.8 no.2
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    • pp.93-106
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    • 1995
  • To investigate the forest structure in Ijontong Cholto area, twenty four plots were set up (each l0$\times$10m ) and surveyed. According to the analysis of ordination by DCA, community divided into 5 groups. The divided groups are Quercus serrata -Q. valiabilis community(I), Q. serrata - Pinus densiflora community(II), Q. mongolica - Lindera obtusiloba community(III), Carpinus laxiflora - Acer pseudo-sieboldianum community(IV) and Acer mono community(V). So the successional trends seems to be from P. densiflora through Q. serrata, Q. valiabilis, Q. mongolica to C. laxiflora, C. cordata, A. mono in canopy layer. And in the subtree and shrub layer, it was expected that from Rhododendron mucronulatum, Rh. schlippenbachii to A. pseudo-sieboldianum, L. obtusiloba. But some sites were likely to become Q. mongolica edaphic climax.

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The Plant Community Structure of Pinus densiflorain Forest in Chuwangsan National Park (주왕산국립공원의 소나무림 군집구조)

  • Jo, Jae-Chang;Cho, Woo;Han, Bong-Ho
    • Korean Journal of Environment and Ecology
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    • v.8 no.2
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    • pp.121-134
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    • 1995
  • To investigate the plant community structure in Pinus densiflora forest of Chuwangsan National Park, twenty five plots were set up and surveryed. The classification by TWINSPAN and DCA ordination techniques were applied to the study area. The plant community were divided into five groups in twenty five plots by DCA and the dividing groups were Pinus densiflora-Quercus variabilis community(I), P. densiflora-Q. serrata community(II), P. densiflora-Fraxinus sieboldiana community(III), P. densiflora-F. sieboldiana-Q. spp. community(IV) and P. densiflora-mixed deciduous forest community(V). The successional trends of tree species by DCA ordination techniques and DBH class distribution analysis seems to be from P. densiflora through Q. mongolica, Q. serrata to Carpinus laxiflora in the canopy layer group. And in the subtree and shrub layer, it was expected that Lespedeza maximowiczii, L. cytobotrya, Rhododendron mucronulatumlongrightarrowStyrax obassia, Stephandra insisa, Zanthoxylum schinifolimlongrightarrowAcer pseudo-sieboldianum, Lindera obtusiloba. There was no difference between the stand scores of DCA and soil pH, and soil moisture.

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The Analysis of the Forest Community Structure of T$\v{o}$kyusan National Park- Case Study of Paekryunsa-Kumpotan - (덕유산 국립공원의 삼림군집구조분석 -백련사-금포탄 지역을 중심으로-)

  • 이경재;최송현;조현서;이윤원
    • Korean Journal of Environment and Ecology
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    • v.7 no.2
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    • pp.135-154
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    • 1994
  • To investigate the forest structure in valley of Kumpotan-Paekryunsa of Tokyusan National Park, fourty plots were set up and surveyed. According to the analysis of classification by TWINSPAN, community divided by 8 groups. The divided groups are Carpinus laxiflora-C. cordata community(I), Pinus densiflora-C. laxiflora-Quercus serrata community(II), C. laxiflora community(III), Q. mongolica-C. laxiflora community(IV), Q. spp. community(V, Ⅵ), and Fraxinus mandshurica community(Ⅶ, Ⅷ). In the analysis of ordination techniques, DBH distribution, environmental variables etc., community Ⅶ and Ⅷ were pointed out edaphic climax. So the successional trends seems to be from P. densiflora through Q. mongolica, Q. serrata to C. laxiflora, C. cordata, F. mandshurica in canopy layer. And in the subtree and shrub layer, it was expected that Rhododendron mucronulatum, Rh. schlippenbachii, Rhus trichocarpalongrightarrowAcer pseudo-sieboldianum, Lespedeza maximowiczii, Euonymus oxyphyllus, Symplocos chinensis for. pilosalongrightarrowStaphylea bumalda, Weigela subsessilis. According to the results of the analysis for the relationship between environmental variables and species, F. mandshurica correlated with exchangeable cations significantly.

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Studies on Restoration of Forest-Floor Vegetation Devastated by Recreational Trampling (I) -Seeding, Fertilizing and Soil Surface Treatment Effect on Restoration of Forest-Floor Vegetation- (답압(踏壓)으로 훼손(毁損)된 임간나지(林間裸地)의 임상식생복원(林床植生復元)에 관한 연구(硏究)(I) -임상식생복원(林床植生復元)에 미치는 파종(播種), 시비(施肥) 및 표토처리효과 (表土處理效果)-)

  • Oh, Koo Kyoon;Woo, Bo Myeong
    • Journal of Korean Society of Forest Science
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    • v.81 no.1
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    • pp.53-65
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    • 1992
  • For elucidating effective methods of restoration of forest recreational sites where management goals are maintaining naturalness and conserving natural ecosystem, seeding, fertilization and soil surface treatment were used for four years at the devastated forest-floor. For restoration of forest-floor vegetation, factorial experiment was used with a split plot design(main plot : fertilization, subplot : soil surface${\times}$seeding) and a randomized complete block design (fertilization${\times}$seeding) at the Kwanaksan Aboretum, Anyang, Kyonggido. Results were summarized as follows : Soil surface softening with tipping and ripping and straw-mat mulching (70% coverage) treatment was effective on germination, survival and growth of seeded vegetation at devastated forest-floor. Especially, straw-mat mulching treatment was effective on soil surface stabilization and seedling's survival at eroded soil surface, while complete soil surface softening treatment was effective on germination, survival and early growth of tree species of late-successional series. Introducing seeds of native species of pioneer or early-successional series, with good growth capability in barren soil was effective on rapid restoration in devastated forest-floor with its soil surface previously compacted and its surviving seeds washed away. When the seeding and straw-mat mulching after partial soil surface softening with tipping and ripping treatment were employed, it took about three years to restore the devastated forest-floor where surface erosion had been undertaken for an extended period of time and where naturally surviving seeds of native species had been washed away. Softening treatment of soil surface was effective for about two years, and seeding and soil surface treatment increased number of seedlings and improved soil surface environment through fixing of movement of the fallen leaves. Fertilizing effect was not oberserved, mainly due to seeding exposure and poor physical condition including soil surface erosion, low soil water potential and drought, etc, at the field experimental site. However, application of nitrogen and phosphate fertilizers was effective on seedling survival of the species in late-successional series, while lime application adversely affected the seedling survival.

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Actual Vegetation and Structure of Plant Community in Daegwallyeong Ranch, Gangwon-do (Province) (강원도 대관령 목장 현존식생 및 식물군집구조)

  • Noh, Tai-Hwan;Han, Bong-Ho;Kim, Jong-Yup;Lee, Min-Young;Yoo, Ki-Joon
    • Korean Journal of Environment and Ecology
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    • v.27 no.5
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    • pp.579-591
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    • 2013
  • This study was carried out to investigate the actual vegetation, the structure of plant community, and ecological succession sere of forest ecosystem in temperate northern climate zone, Daegwallyeong Ranch, Gangwon-do (Province) and to offer the basic data for planning of the forest managemant. As a result of analysis of actual vegetation, vegetation types divided into 56types and the area of survey site was $19,397,361m^2$. The ratio of vegetation type dominated by Quercus mongolica forest was 39.1%, primary grassland was 24.7%, Quercus mongolica-Deciduous broad-leaved forest was 11.3%. Twenty eight plots (size is $20m{\times}20m$) were set up and the results analyzed by DCA which in one of the ordination technique showed that the plant communities were divided into six groups which area community I (Pinus densiflora-Quercus mongolica community), community II (Quercus mongolica-Pinus densiflora community), community III (Quercus mongolica community), community IV (Quercus mongolica-Deciduous broad-leaved community), community V (Deciduous broad-leaved community), community VI (Sorbus alnifolia community). The age of community Iwas ranged from 57 to 62 years old, that of community IIwas ranged from 41 to 77 years old, community III was ranged from 47 to 108 years old, community IV was ranged from 47 to 82 years old, community V was 47 years old, community VI was 55 years old, thus we supposed that the age of the study site is about from 41 to 108 years old. The Ecological succession is predicted from Pinus densiflora community to Quercus mongolica community and Deciduous broad-leaved were distributed in the center of the valley in Daegwallyeong Ranch. According to the index of Shannon's diversity (unit: $400m^2$), community IV was ranged from 0.8203 to 1.1439, community III was ranged from 0.8019 to 1.1375, community V was 1.0993, community I was ranged from 0.9475 to 1.0797, community II was ranged from 0.6896 to 1.0324, community VI was 0.9909.

Extreme Event Analysis Using High Resolution RCM Climate Change Precipitation Scenario and CWGEN in Korea (고해상도의 강수변화 시나리오와 CWGEN을 이용한 극한 강우 특성에 관한 연구)

  • Kwon, Hyun-Han;Kim, Byung-Sik;Yoon, Seok-Young
    • Proceedings of the Korea Water Resources Association Conference
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    • 2008.05a
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    • pp.279-283
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    • 2008
  • 국외를 중심으로 기존 GCM보다 해상도가 높은 Regional Climate Model(RCM)을 이용한 분석이 일부 시행되고 있으나, 국내에서는 이를 이용한 연구가 아직 미비한 실정이다. 이러한 관점에서 본 연구에서는 27km의 해상도를 갖는 기상청 RegCM3 RCM에서 도출된 기후변화 SRES 시나리오 자료를 이용하고자 한다. 수자원의 장기 거동을 강우-유출 모형으로 모사하기 위해서는 입력 자료인 일 강수자료 계열을 모의발생이 필요하며 본 연구에서는 천이확률 및 강수 모의에 이용되는 Gamma 확률분포와 같은 분포형의 매개변수들이 외부 인자 즉 기후변화 시나리오에 따라 조건부로 변동할 수 있는 CWGEN(Cross-validated Canonical Correlation Analysis-Weather Generator) 강수 모의기법을 도입하여 이용하였다. RCM 자료 그 자체는 일반적으로 시 공간적으로 왜곡되어 있어 Quantile Mapping을 통하여 수정을 하였다. 최종적으로 모의된 결과를 바탕으로 기후변화에 따른 극치사상들에 대한 정량적인 거동을 추정하고 평가하였다.

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