• 한국지리정보학회지
• /
• 제2권3호
• /
• pp.16-22
• /
• 1999

생물서식지의 다양한 공간구조는 생물의 종 다양성과 밀접한 관계를 가지고 있다. 인구의 증가, 농업의 발달, 그리고 도시의 발전은 최근에 다양한 경관의 변화를 가져왔다. 이러한 경관의 변화는 생태적 구성인자의 서식지 감소와 파편화(fragmentation)를 초래하였다. 본 연구에서는 Landsat TM을 이용하여 식생지수를 산출하고 이를 식생 패치의 경계길이 대 면적 (perimeter : area, P/A ratio), Shape Index(SI), 프렉탈 디멘죤(D)에 의해 추출한 파편화지수를 분석하였다. NDVI에 의한 경관파편화의 분석은 0.5~1의 구간 값을 이용하는 것이 가장 파편화를 용이하게 구분할 수 있음을 알 수 있었다. 또한, 서울 경기지역의 식생 파편화는 프렉탈 디멘죤에 의해 구분할 때 가장 효과적으로 식생 패치의 파편화를 구분해 낼 수 있음을 알 수 있었다. 향후 동일지역에 대한 식생 패치의 시계열적인 분석과 다양한 토지이용에 대한 식생 파편화의 분석을 비교 연구하여 식생 보전과 생물다양성의 전략을 제시할 수 있을 것이다.

• 한국환경복원기술학회지
• /
• 제15권2호
• /
• pp.149-162
• /
• 2012

Habitat loss and fragmentation are ongoing major anthropogenic impacts on landscapes, which can strongly affect ecosystems, populations and species. The studies on forest fragmentation have been progressed, but the studies on definition of forest fragmentation and their synthetic trend in South Korea still leaves much to be desired. Therefore we set the definition of forest fragmentation and reviewed the related papers. We can give a definition that forest fragmentation is not only a process of spatial landscape transformation, but also a process of ecosystem change by it. The trend of studies on forest fragmentation divided into two fields, landscape and ecosystem changes. Forest fragmentation caused by land change altered the composition and configuration of forest patches. Most studies related on that analyzed the change using landscape index. The effects of forest fragmentation on ecosystem subdivided into three fields : biodiversity, edge effects, and invasive species, but the studies in South Korea is short. The study on relations between forest fragmentation and ecosystem change is necessary to face the Convention on Biological Diversity in South Korea. In addition, the fundamental studies on biodiversity is important to mitigate against forest fragmentation.

• 대한토목학회논문집
• /
• 제32권6B호
• /
• pp.387-397
• /
• 2012

본 연구에서는 홍천강 11 km를 대상으로 수변생태벨트를 조성할 경우 벨트 폭에 따른 하천 단절성 개선 효과를 분석하였다. 홍천강 대상구간은 기존의 연구에서 하천 단절성이 심화되었다고 보고된 구간으로, 대상지의 생태적 연결성을 증진시키기 위해 필요한 수변생태벨트의 적정 폭을 선정하고자 하였다. 이를 위해 하천을 1 km의 구간으로 구분하여 A-K의 총 11개 구간에 대한 도상조사 및 현장조사를 수행하였다. 또한 단절지수를 적용하여 도로, 제방 및 주변 토지이용 등에 의한 연결성 단절과 생태적 기능성 단절 항목을 평가하였다. 그 결과, I 구간에서 연결성과 생태 기능성 단절이 가장 큰 것으로 분석되었으며, 수변벨트를 조성하지 않은 현 상태에서는 구간별 평균값이 단절 2등급을 보이는 것으로 나타났다. 또한, 폭 10-50 m의 수변벨트를 조성하였을 경우, 연결성 단절에 대한 개선 효과는 미비하였으나 생태적 기능성 단절에 대해서는 12.4-25.1%의 개선효과가 있는 것으로 예측되었다. 한편, 10 m와 30 m를 조성하였을 경우 단절성 저감효과가 크게 나타났으며, 특히 30 m 조성시 단절등급이 2등급에서 3등급으로 완화되는 효과를 보이는 것으로 나타났다.

• 터널과지하공간
• /
• 제13권6호
• /
• pp.444-454
• /
• 2003

최근 TBM등의 기계식 터널 굴착에 널리 사용되는 커터 디스크 관입에 의한 암석 파쇄 기술은 커터디스크 관입에 따라 국부적으로 높은 응력이 발생하고 미소균열이 생성 및 전파되는 과정이며, 이러한 현상은 암석의 불균질성에 기인한다. 따라서 본 연구에서는 수치해석적으로 TBM에 의한 파괴 메카니즘을 규명하기 위하여. Weibull 분포함수를 이용하여 암석의 불균질 강도 물성을 고려하였으며, 파괴후 물성 저하를 고려하기 위하여 저감지수를 도입하였다. 본 연구결과로부터 단일 커터 디스크 관입시 측압이 매우 중요한 영향을 미치며, 측압이 작을수록 관입에 저항하는 강도는 약하여 커터 디스크와 접촉하는 면과 수직한 방향으로 파괴가 잘 발생하고 측압이 클수록 암석 표면을 따라 chipping 현상이 잘 나타났다. 또한 두 개의 커터 디스크가 작용하는 경우 파괴영역이 전파되고 상호 연합되어 최종적으로 파괴가 발생하는데, 커터 디스크 간격이 70 mm인 경우가 40 mm와 100 mm인 경우 비해 좋은 파쇄효율을 나타내었다. 이상의 결과로부터 커터 디스크 관입에 의한 암석의 chipping 과정 및 메카니즘의 이해와 TBM 터널 설계를 위한 다양한 검토를 해석적 기법으로서 제시할 수 있을 것으로 기대된다.

• Imaging Science in Dentistry
• /
• 제31권4호
• /
• pp.227-233
• /
• 2001

Purpose: The purpose of this study was to investigate the apoptosis induction in tissues constituting the craniofacial region of growing rat by irradiation. Materials and Methods: The submandibular gland, brain, articular cartilage of condylar head, and calvarium were extracted from 20-day-old rats irradiated 10 Gy. Apoptosis of each tissue was examined by DNA fragmentation and estimated quantitatively using apoptotic index on TUNEL assay. Apoptotic index of each tissue was calculated by the equation for apoptotic cells/total cells × 1,000 on the images of confocal laser scanning microscopy. Apoptotic index was analyzed statistically according to the time lapse after irradiation on the tissues. Results : In the submandibular gland, apoptotic index was significantly increased from 6 hours after irradiation showing the highest value at 12 hours and decreased to the control level at 3 days after irradiation. In the brain, apoptotic index was abruptly reached to the maximum value at 6 hours after irradiation and decreased to the control level at 4 days after irradiation. Articular cartilage and calvarium showed no or little apoptotic signals. The results obtained by the apoptotic index accorded with that of DNA fragmentation. Conclusion : Radiation was closely related with the apoptosis of submandibular gland and brain but, not related with the apoptosis of the articular cartilage of condylar head and calvarium. The changes induced by radiation of the hard tissues would not be explained by apoptosis.

• Geomechanics and Engineering
• /
• 제16권2호
• /
• pp.195-204
• /
• 2018

Based on theories of rock mechanics, rock fragmentation, mechanics of elasto-plasticity, and energy dissipation etc., a method is presented for evaluating the rock fragmentation efficiency by using plastic energy dissipation ratio as an index. Using the presented method, the fragmentation efficiency of rocks with different strengths (corresponding to soft, intermediately hard and hard ones) under indentation is analyzed and compared. The theoretical and numerical simulation analyses are then combined with experimental results to systematically reveal the fragmentation mechanism of rocks under indentation of indenter. The results indicate that the fragmentation efficiency of rocks is higher when the plastic energy dissipation ratio is lower, and hence the drilling efficiency is higher. For the rocks with higher hardness and brittleness, the plastic energy dissipation ratio of the rocks at crush is lower. For rocks with lower hardness and brittleness (such as sandstone), most of the work done by the indenter to the rocks is transferred to the elastic and plastic energy of the rocks. However, most of such work is transferred to the elastic energy when the hardness and the brittleness of the rocks are higher. The plastic deformation is small and little energy is dissipated for brittle crush, and the elastic energy is mainly transferred to the kinetic energy of the rock fragment. The plastic energy ratio is proved to produce more accurate assessment on the fragmentation efficiency of rocks, and the presented method can provide a theoretical basis for the optimization of drill bit and selection of well drilling as well as for the selection of the rock fragmentation ways.

• 생명과학회지
• /
• 제7권4호
• /
• pp.336-341
• /
• 1997

This study was conducted to investigate the effects of carcass grade on the hardness, myofibrillar fragmentations index, protein extractability and Mg-ATPase activity of myofibril and actomyosin obtained from 1, 2, 3 and D carcass grade)subgrade) in Korean native cow. Proximate component, hardness, chewiness, myofibril fragmentation index, protein extractability and Mg-ATPase activity if myofibril or actomyosin were not significantly different between 1st and 2nd carcass grade loin. The hardness and chewiness of 2nd carcass grade loin's were significantly lower than 3th grade loin's, but the myofibril fragmentation index, sarcoplasmic protein extractability and Mg-ATPase activity of myofibril were higher. The myofibrillar protein extractability and Mg-ATPase activity of actomyosin obtained from 3th carcase grade loin's were significantly higher than D grade loin's, but the hardness, chewiness and stroma protein extractability were lower. In conclusion, the degree of toughness in Korean native cow's loin was not significantly different between 1st and 2nd grade, but 3rd and D carcass grade were significantly higher, regardless of before and after aging.

• 한국식품영양과학회지
• /
• 제26권4호
• /
• pp.647-653
• /
• 1997

도축 후 2일간 냉장한 한우(♀, 380kg)와 홀스타인(♀, 490kg)의 안심부위를 이용하여 단기숙성용은 함기포장하여 14일간, 장기 숙성용은 진공포장하여 28일 동안 3$^{\circ}C$에서 냉장숙성하면서 경시적으로 전단력가, 근원섬유의 Mg-ATPase활성, 근원섬유의 소편화도, 근원섬유의 소편화율, 그리고 30,000 dalton(30KD)성분의 출현정도에 대하여 경시적으로 실험하여 숙성도 지표로 적당한 지를 검토하였다. 우육안심을 함기포장하여 3$^{\circ}C$에서 14일간 숙성할 때의 숙성도 지표로 적합한 물리화학적 성질로서는 전단력가(r=-0.893)>근원섬유 소편화율(r= 0.863)〉30KD성분의 출현(r=0.853)>근원섬유 소편화도 (r=0.814)>근원섬유 Mg-ATPase활성 (r=0.804)의 순으로 유효하였다. 그리고 진공포장하여 28일간 숙성할 때는 근원섬유 소편화율(r=0.880)〉30KD성분의 출현(r=0.836)의 순이었다. 함기포장육의 경우 숙성도 지표들간의 상관관계는 근원섬유의 소편화율이 전단력가, Mg-ATPase활성, 근원섬유 소편화도, 30KD성분의 출현과 상관관계가 있었으며 진공포장육은 근원섬유 소편화율이 30KD성분의 출현과 상관관계가 있었다

• 한국환경복원기술학회지
• /
• 제19권3호
• /
• pp.29-44
• /
• 2016

The purpose of this study is to quantitatively and visually analyze the degree of green biotope fragmentation caused by road construction and other development work using FRAGSTATS and GUIDOS tool. Moreover, linking of the endangered species research, we mapped "Biotope Fragmentation Map" of Daejeon-city. The findings of the study are summarized as follows: First, as the result of FRAGSTATS, landscape indices : number of patch(NP), mean patch size (MPS), edge length(TE), mean nearest neighbor distance(MNN), edge shape(LSI) showed meaningful change from fragmentation. Moreover, the result of GUIDOS analysis, middle core-small core-bridge-branch-edge-islet-perforation showed increase of area percentage without large core. Lastly, analysis result of 'Biotope Fragmentation Map' revealed that changing site of large core's size appeared eighteen-site and designated as the special protection area appeared forty-one site. As the result of the two data, overlapping areas that showed both change of core size and revealed special protection areas revealed four site. For example, five species of endangered species appeared on the NO. 4 site in 'Biotope Fragmentation Map'. The findings of this study as summarized above are considered to play an important role in basic data preventing green biotope fragmentation at the planned level from various development work.

• 한국축산식품학회지
• /
• 제18권3호
• /
• pp.216-223
• /
• 1998

This study was conducted to investigate the effects of the tenderness for the vacuum chilled, the air-frozen or the rechilled Holstein beef loin. The vacuum packaged beef was stored at 1$^{\circ}C$ and the air-packaged beef was stored at -20$^{\circ}C$ for 60 days. The rechilled beef was restored for 3 days at 1$^{\circ}C$ by using the vacuum chilled or the air-frozen beef. Hardness and chewiness of the vacuum chilled beef were better than those of the air-frozen beef. Hardness and chewiness were improved significantly(p＜0.05) after the 40 days storage for the vacuum chilled beef, but there was no significant improvement for the air-frozen beef during the 60 days storage. By the rechilling process, tenderness and myofibrillar fragmentation index of the vacuum chilled and air-frozen beef improved. Especially those were improved significantly(p＜0.05) in the vacuum chilled beef after the 20 days storage, and in the air-frozen beef after the 40 and 60 days storage.