• Korean Journal of Environment and Ecology
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• v.3 no.1
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• pp.81-94
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• 1989

Use impacts to trail and campground deteriorations and their changes of natural environment were studied in Mt. Kaya National Park in 1989. The entire width, bare width and maximum depth of trail as the trail condition were significantly greater on the more heavily used trail. Deteriorations of trail which were surveyed at the total of 51 were significantly different from those of non-deteriorated points. The changes of soil and vegetation of trailsides were not found at a uniform tendency but could be more clearly grouped by the types of user's disturbance, and use impact on trailside had reached 15m inside of forest. Percentage of area for Class 5 in campsite was about 36% and about 69% of campsite area was more severe than Class 3. Recreational activities retarded the diameter growth of trees in campsite and accelerated the different composition of species. Soil and vegetative factors adapted to understand the difference of use amount and the realm of use impact could be sorted. The realm influenced by user's disturbance was about 50m from the core of campsite. Fraxinus rhynchophylla, Rhus trichocarpa, Symplocos chinensis for. pilosa and Stephanandra incisa were considered as the tolerant species to user's impact.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.118-118
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• 2010

현재 반도체 제조 공정 중 많은 비중을 차지하는 식각 및 증착 공정에는 대부분 플라즈마를 사용하고 있으며, 이러한 반도체 장비내의 공정 부분품들은 수율과 생산성을 향상시키기 위하여 내플라즈마 특성이 우수한 세라믹 또는 세라믹 코팅막으로 구성되어 있다. 더욱이 최근에는 미세공정을 위해 고밀도 플라즈마 공정이 요구되면서, 노출된 세라믹 층이 침식되어 파티클이 떨어져 나오거나 모재와 세라믹 막 사이의 박리현상과 같은 심각한 문제들이 발생되고 있다. 따라서 보다 우수한 내플라즈마 특성을 갖는 세라믹 코팅 기술 개발이 시급한 실정이다. 현재 내플라즈마성 세라믹 코팅막 제조를 위한 코팅기술로서는 주로 용사법이 이용되고 있으나 기공률이 높고 치밀하지 못한 등의 문제점으로 인하여 사용수명이 짧다는 한계에 봉착하였다. 이에 본 연구에서는 상온에서 치밀하고 고속으로 세라믹 후막 형성이 가능한 Aerosol Deposition (AD)법과 AD법의 단점인 edge, corner, hole에서 코팅이 잘 안 되는 점을 보완할 수 있는 Arc Plasma Anodizing (APA)법을 조합하여, 상용화된 Al 모재위에 APA법을 사용하여 $Al_2O_3$ 후막 중간층을 형성한 뒤 그 위에 AD법으로 치밀한 $Al_2O_3$ 후막 성막함으로써 내 플라즈마 향상을 위한 새로운 개념의 제조기술개발을 시도하였다. 이를 위해 우선 Al 모재 위에 APA를 사용하여 중간층인 $Al_2O_3$막을 제조하였으며, 중간층의 두께에 따른 특성을 확인한 결과, $Al_2O_3$중간층의 두께가 두꺼워질수록 표면조도가 증가함을 확인 할 수 있었다. AD법으로 $Al_2O_3$중간층 위에 치밀한 $Al_2O_3$막을 제조하는데 있어 중요인자를 확인하기 위해, AD법으로 중간층 위에 $Al_2O_3$막을 제조한 후 성막특성을 관찰하였다. 그 결과, 중간층의 표면조도가 $0.8-1\;{\mu}m$인 경우에는 수 ${\mu}m$의 두께로 성막 되었으나, 표면조도가 $1\;{\mu}m$ 이상인 $Al_2O_3$중간층 위에서는 성막 되지 않았다. 이를 통해 AD법으로 치밀하고 두꺼운 $Al_2O_3$ 후막을 $Al_2O_3$중간층 위에 성막하기 위해서는 표면조도가 중요인자임을 확인하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.613-613
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• 2015

최근 전 지구적인 온난화로 인한 이상기후에 따라 강수량이 증가하고, 특정지역에만 국한되어 집중적으로 비가 내리는 국지성 집중호우의 발생 빈도가 증가하여 이로 인한 극한 홍수나 강우로 인한 산사태 등의 재해가 반복적으로 발생하고 있다. 홍수는 재산 및 인명에 이르기까지 막대한 피해를 야기한다는 점에서 이를 대비하기 위한 방안이 필수적이므로 국가적인 차원에서 홍수피해를 경감시키기 위한 여러 가지 구조적 또는 비구조적 대책들을 제시하고 있지만, 정확한 기상 변화의 예측이 어렵고 다양한 유발 원인들로부터 비롯된 홍수에 모두 대응할 수 있는 통합 대책 마련이 어려운 실정이다. 즉, 사전예방보다는 피해 복구에만 중점을 두고 있기 때문에 홍수 발생 유역의 지역적인 홍수피해 특성을 반영하지 못할 뿐만 아니라 어느 지역이 상대적으로 홍수피해의 위험성이 높은 지역인지도 파악하기 어렵다. 따라서, 본 연구에서는 도시홍수피해 유형인 내수침수피해와 외수침수피해의 유형에 따라 사례들을 조사하고 관련문헌들로부터 도시 홍수 취약성 평가를 위한 대표적 인자들을 도출하였다. 도출된 인자들을 각각 IPCC의 취약성 평가 프레임에 따라 기후노출, 민감도 그리고 적응능력으로 구분하고 도시 상습침수지역인 도림천 유역을 시범 지역으로 하여 도시홍수 취약성 평가를 위한 지수를 개발하고자 한다. 본 연구를 통하여 향후 도시홍수피해의 잠재적 위험성이 높을 것으로 판단되는 유역에 대한 활용방안을 제시하고 유역의 특성 및 중요도에 따른 치수사업의 우선순위를 결정하는 등 유역의 특성을 반영한 구체적 적응정책의 방향성을 세우는데 기초자료로 제공될 수 있으며, 도시홍수로 인한 인명 및 재산의 피해를 최소화 하는 것에 목적이 있다.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.3
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• pp.359-366
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• 2021

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked recessive disorder and is the most common enzyme deficiency worldwide. Although this disease is rare in Korea, its prevalence may increase due to an increase of multicultural families. Patients with this deficiency are prone to hemolytic anemia provoked by specific drugs commonly used or prescribed in pediatric dentistry. It is necessary for pediatric dentists to have accurate knowledge of a patient's medical history and to consult with a pediatric hematologist to avoid oxidative stress that can lead to hemolysis. The most effective treatment is prevention of exposure to factors that may trigger anemia. Appropriate education regarding risk factors is essential for patients diagnosed with this disease. This case report aimed to discuss the drugs and dental management methods that should be cautious in children with G6PD deficiency.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.307-313
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• 2022

In this study, the correlation between Half Cell Potential(HCP) and the corrosion influencing factors was analyzed with considering three levels of water-cement ratio, the concentration of chloride solution, and cover depth. As a result of long-term corrosion monitoring, HCP behavior was close to the critical corrosion potential(-350 mV) in all water-cement ratios in the case of 3.5 % and 7.0 % chloride concentration. Regarding the passed charge test in 548 curing days, the passed charge results were improved to 'Moderate' grade. Multiple regression analysis was performed to evaluate the correlation between corrosion influencing factors and HCP, and it was evaluated that the effects of influencing factors to HCP were in the order of chloride concentration, water-cement ratio, and cover depth. In the case of the relationship between HCP and the passed charge, the coefficient of determination showed a high level of 0.9, which yielded a close correlation between the passed charge and HCP.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.154-154
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• 2020

최근 국지성 호우가 빈번하게 발생하고 있고, 이로 인해 국내 도시지역 홍수피해 발생빈도와 피해규모가 증가하고 있다. 2010년, 2011년, 2018년에 서울에서는 홍수로 인한 침수피해가 크게 발생하여 많은 인명과 재산의 피해가 있었다. 이렇듯 도시지역은 타 지역에 비해 인구와 재산이 밀집되어 있어 홍수 취약성이 상대적으로 높은 지역이다. 국내에서는 홍수피해 저감을 위해 홍수예보를 발령하고 있다. 하지만 국내 홍수예보는 국가하천 및 지방하천의 주요 하천 구간에서만 실시되고 있어 이러한 하천에 접하지 않는 지역은 국가 홍수예보의 수혜를 받을 수 없다. 그렇기 때문에 각 지역에서는 홍수 대응을 위해 기상청의 호우특보 기준을 사용하고 있으며 이 기준은 전국적으로 동일하다는 특징이 있다. 하지만 각 도시지역은 과거 홍수피해에 따라 방재시설을 추가로 설치하거나 보수하고 있어 각 지역의 방재시설 현황 및 홍수에 대한 취약성 정도가 다른 상황이다. 그러므로 전국적으로 동일한 강우기준이 적용되어 발령되고 있는 호우 특보는 실제 각 도시지역의 방재현황이 고려되지 못한다는 문제가 있다. 이와 관련하여 과거 낙동강 지역을 대상으로 지역별 홍수위험도에 따른 홍수위험지수를 산정하고 검토한 연구가 수행된 바 있다. 본 연구에서는 각 도시지역의 방재 현황을 고려하여 강우기준을 보정할 수 있는 가중치를 산정하는 방안에 대해 제시하였다. 이를 위해 서울 지역 25개 기초지자체를 대상으로 연구를 진행하였으며, 홍수 취약성을 평가하기 위한 세부인자는 노출도, 민감도, 적응도로 구분하였다. 각 세부인자 별 가중치를 산정하기 위해서는 엔트로피 방법을 적용하였고, 산정된 결과를 이용하여 각 지역 별 가중치를 산정하기 위해서는 유클리드 거리 산정법을 적용하였다. 그 결과 각 지역의 방재 특성을 고려한 가중치를 산정할 수 있었으며 향후에는 지역 별 방재특성이 고려된 강우기준을 제시 및 적용성을 검토할 계획이다.

• Journal of Life Science
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• v.33 no.7
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• pp.586-592
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• 2023

Oxidative stress is a critical factor affecting the quality and viability of sperm during boar semen storage. Oxidative stress is also a significant concern during the process of freezing semen. The process of semen storage involves exposing the sperm to various stressors, including temperature changes, cryoprotectants, and extended periods of incubation. In addition, oxidative stress can lead to the production of reactive oxygen species (ROS) within the sperm, resulting in oxidative damage to cellular components, such as lipids, proteins, and DNA. Striking a balance between ROS production and the antioxidant defense system is crucial for maintaining sperm viability and functionality during semen storage. Moreover, the prolonged storage of boar semen leads to an increase in ROS levels, which can impair sperm motility, membrane integrity, and DNA integrity. ROS-induced lipid peroxidation affects the fluidity and stability of sperm membranes, leading to decreased sperm motility. Moreover, oxidative damage to the DNA can result in DNA fragmentation, compromising the genetic integrity of the sperm. In conclusion, oxidative stress is a significant challenge in maintaining sperm quality during boar semen storage. Understanding the mechanisms underlying oxidative stress and their impacts on sperm function is crucial for developing effective strategies to minimize oxidative damage and improve sperm storage outcomes.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.3
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• pp.271-276
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• 2024

Traditional oil, a depleting resource, accounts for only one-third of the world's oil reserves, so research and cases of utilizing non-traditional oil as a resource are continuously increasing. However, unconventional oil contains bitumen containing solid particles such as sand, and because it is exposed to a high temperature and high pressure environment, deformation can frequently occur in oil pipelines. Therefore, variables such as material, thickness, and angle that can affect the deformation of the oil pipeline were derived and applied to the oil pipeline, and finite element analysis was performed using the Ansys program. As a result of finite element analysis, deformation and maximum load capacity were derived. Afterwards, the same analysis was performed by modeling an optimized oil pipeline by combining the factors with the best deformation resistance and maximum load capacity. As a result of the analysis, the effect of reducing deformation and increasing the maximum load capacity by about 30 % was confirmed, and factors for suppressing deformation when analyzing oil pipelines were derived.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.4
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• pp.471-479
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• 2012

This study was conducted to investigate the effects of various levels of chitosan oligomer (CO) molecular weight on the disorders of lipid metabolism and immune-related factors induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), that is a endocrine disrupter, using adult male rats (SD) for 3 weeks. These 40 animals were divided into five groups. Three kinds of CO were used by molecular weight (MW) (less than 1000, 1000~3000, and 5000~10000) and added 4% to basal diets respectively. TCDD (40 ${\mu}g$/kg B.W) was intraperitoneally injected into rats at the beginning of the experiment. The relative weights of the livers were increased in all rats treated with TCDD, and the brain and testis weights were increased in all CO diet groups, compared to the control and TCDD groups. The levels of white blood cells (WBC) and red blood cells (RBC), hemoglobin, hematocrits (HCT), and platelets were significantly lowered by treating TCDD. By the way, RBC and HCT tended to recover by CO diets. The elevation of serum total and HDL cholesterol levels induced by TCDD treatment was significantly reduced by CO (5000~10000 MW) diets. The apparent increasing of the total lipid, cholesterol, and triglyceride levels of rat livers induced by TCDD was tended to be suppressed in those fed CO diets. Especially, diets with less than 1000 MW significantly diminished liver triglycerides. The levels of serum immunoglobulin (Ig) A, IgG1 and IgM were significantly high in rats fed CO (5000~10000 MW) diets. The decreasing levels of IgE by treatment with TCDD tended to recover all the CO diet groups to the level of control group. In histochemical observation, the fat droplets and apoptosis of liver due to TCDD treatment were markedly alleviated in all CO diet groups. These results indicated that CO, though not regular according to molecular weight, can exert improving effects on lipid accumulation, hepatocytic disorders, abnormal blood cells, and some immunoglobulins induced by TCDD.

• Korean Journal of Environment and Ecology
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• v.35 no.1
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• pp.68-80
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• 2021

This study aimed to provide basic data such as the structure of the Carpinus turczaninowii community and characteristics of the habitat environment for ex situ conservation by analyzing the plant community structure of Carpinus turczaninowii, an island plant resource. For the community structure analysis, this study established 29 plots, sized 100㎡ each, in Seokmo, Yeongjong, Yeongheung, and Daebu islands. TWINSPAN was used for the classification of communities. The classification identified six communities. Group I was the C. turczaninowii-Quercus serrata community, group II was the C. turczaninowii-Pinus densiflora community, group III was the C. turczaninowii-Quercus mongolica community, group IV was the C. turczaninowii-Sorbus alnifolia community, group V was the C. turczaninowii typical community, and group VI was the C. turczaninowii-Quercus variabilis community. The species diversity was 0.90008~1.12868, the dominance was 0.17536~0.25665, and the similarity index was 17.1429~38.2979%. The result of correlation analysis of 7 environmental factors for 6 communities by RDA ordination showed a positive correlation between the crown density and litter layer and a negative correlation between the bare rock, soil hardness, and altitude on the 1st axis. On the 2nd axis, the bare rock and crown density showed a positive correlation, and the slope showed a negative correlation. In the C. turczaninowii-Quercus serrata community (I), the crown density and the litter layer were the environmental factors affecting the vegetation distribution. In the C. turczaninowii-Pinus densiflora (II) and C. turczaninowii-Quercus mongolica (III) communities, the slope was the factor affecting vegetation distribution. In the C. turczaninowii-Sorbus alnifolia (IV), C. turczaninowii typical (V), and C. turczaninowii-Quercus variabilis (VI) communities, the bare rock, altitude, and soil hardness were the factors affecting vegetation distribution.