• 한국환경복원기술학회지
• /
• 제24권3호
• /
• pp.85-98
• /
• 2021

In this study, the characteristics of tree growth and soil environment were analyzed at 5 sites that had been planted on the back slope of dam for more than 15 years in Korea. First, as a result of investigating the growth of 15 trees planted on the back slope of the dam, the average height was 10.6m, diameter at roots was 27.3cm, and DBH was 22.9cm, showing good growth status of most of the trees. In particular, the growth levels of pine, hackberry, and oak were similar or better than those of general forests and artificial ground. As a result of excavating and investigating the roots of trees, horizontal roots grew well in the left and right directions of the back slope of the dam, and the growth of vertical roots was insufficient. Currently, the roots of trees do not directly affect dam safety, but they may continue to grow in the long term and interfere with dam management. Second, the physicochemical characteristics of the soil on the back slope of dam were generally above the intermediate level in terms of landscape design standards, and were similar to those of the domestic forest soil. Therefore, although it was judged to be suitable for plant growth, isolation of the site, soil acidification, and nutrient imbalance may affect tree growth and forest health in the long term. Through this study, it was possible to confirm the potential and applicability of planting area on the back slope of dam as an ecological base. Continuous monitoring is required for safety management and ecological value of dams in the future, and through this, it will be possible to secure the feasibility of planting trees on the slopes of new or existing dams and improving management.

• 천문학회보
• /
• 제40권1호
• /
• pp.62.1-62.1
• /
• 2015

Polarization of the light reflected off the Moon provides information on the size and composition of the particles in the lunar regolith. The mean particle size of the regolith can be estimated from the combination of the albedo and degree of polarization, while the color ratio of the parallel-component polarization (CP) has been suggested to be related to the amount of nanophase metallic iron (npFe^0) inside the regolith particles. Both the mean size and npFe^0 abundance of the particles have been used as maturity indicators of the regolith since sustained impacts of high energy particles and micro-meteoroids cause comminution of particles and production of npFe^0. Based on our multispectral polarimetric observations of the whole near side of the Moon in the U, B, V, R, and I bands, we compare the maps of the mean particle size, CP, and the optical maturity (OM). We find that the mean particle size map is sensitive to the most immature (~0.1 Gyr) soil, the OP map to the intermediate immaturity (a few 0.1 Gyr) soil, and the CP map to the least immature (~1 Gyr) soil.

• 한국연초학회지
• /
• 제1권1호
• /
• pp.39-45
• /
• 1979

극단의 土壤水分( 4 %, 24% )과 溫度(33$^{\circ}C$, -2$^{\circ}C$)에서 뿌리혹線筮의 生存率을 조사한 결과 土壤水分 함량에 따른 차이는 인정되지 않았고, 溫度 處理의 경우 33$^{\circ}C$에서는 Meloidogyne incognita, -2$^{\circ}C$에서는 M. hapla의 생존율이 높았으며, M. arenaria는 兩 處理에서 양자의 중간 정도의 반응을 보였다. 低溫처리에서 tolerance의 증가는 모든 線筮에서 인정되었으며 특히 M. hapla의 tolerance가 가장 높았다.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2000년도 창립총회 및 춘계학술발표회
• /
• pp.108-111
• /
• 2000

FeS/FeS$_2$ minerals have been known to be potentially useful reductant to the removal of common organic contaminants in groundwater and soil. This research is aimed at improving our understanding of factors affecting the pathways and rates of reductive transformation of Hexachloroethane by catalytical iron minerals in natural system. Hexachloroethane is reduced by FeS/FeS$_2$ minerals under anaerobic condition to tetrachloroethylene and trichloroethylene with pentachloroethyl radical as the intermediate products. The kinetics of reductive transformations of the Hexachloroethane have been investigated in aqueous solution containing FeS, FeS$_2$. The proposed reduction mechanism for the adsorbed nitrobenzene involves the electron donor-acceptor complex as a precursor to electron transfer. The adsorbed Hexachloroethane undergo a series of electron transfer, proton transfer and dehydration to achieve complete reduction. It can be concluded that the reductive transformation reaction takes place at surface of iron-bearing minerals and is dependent on surface area and pH. Nitrobenzene reduction kinetics is affected by reductant type, surface area, pH, the surface site density, and the surface charge. FeS/FeS$_2$-mediated reductive dechlorination may be an important transformation pathway in natural systems.

• 한국토양비료학회지
• /
• 제45권4호
• /
• pp.593-601
• /
• 2012

Heavy metals and metalloids removal can be considered as one of the most important world challenges because of their toxicity and direct impact on human health. Many processes have been introduced but biological processes of remediation seem to offer the most suitable solution in terms of efficiency and low cost. Actinobacteria constitute one of the major microbial populations in soil, and this can be attributed to their adaptive morphological structure as well as their exceptional metabolic power. Among microbes, actinobacteria are morphologic intermediate between fungi and bacteria. Studies on microbial diversities in metal contaminated lands have shown that actinobacteria may constitute a dominantly active microbiota in addition to ${\alpha}$ Proteobacteria. Furthermore, isolation studies have shown metal removal mechanisms which are reminiscent of notable multiresistant strains, such as Cupriavidus metallidurans. Apart from members of genus Streptomyces, which produce more than 90% of commercialized antibiotics, and the nitrogen fixing Frankia, little attention has been given to other members of this phylum. This is because of difficult culture condition requirements and maintenance. In this review, we focused on specific isolation of actinobacteria and their potential applications in metal bioremediation and plant growth promotion.

• Earthquakes and Structures
• /
• 제11권3호
• /
• pp.505-516
• /
• 2016

This paper evaluates the scaling of ground motions recorded from nine intermediate-depth earthquakes produced in the Vrancea seismic zone in Romania. The considered ground motion database consists of 363 horizontal recordings obtained on soil classes B and C (according to Eurocode 8). An analysis of the inter- and intra-event spectral accelerations is performed in order to gain information regarding the magnitude and distance scaling of the Vrancea ground motions. The analyses reveal a significant influence of the earthquake magnitude and focal depth on the distance scaling and different magnitude and distance scaling for the two soil classes. A linear magnitude and distance scaling is inferred from the results for the range of magnitudes $5.2{\leq}M_W{\leq}7.1$. The results obtained are checked through stochastic simulations and the influence of the stress drop and kappa values on the ground motion levels is assessed. In addition, five ground motion models which were tested in other studies using recordings from Vrancea earthquakes are analyzed in order to evaluate their corresponding host stress drop and kappa. The results show generally a direct connection between the host kappa values and the host stress drop values. Moreover, all the ground motion models depict magnitude dependent host kappa and stress drop levels.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제8권2호
• /
• pp.70-77
• /
• 2003

유해유기물질의 미생물 분해시 일어나는 총괄반응을 이론적으로 예측하는 방법을 기술하였다. 열역학적 이론을 바탕으로 하는 반쪽반응 방법을 사용하,였고, 최근에 도입된 이론들인 중간체 생성 반응, oxygenation반응, 그룹이론에 의한 표준 자유생성에너지 예측기법 등을 적용하였다. 대표적인 유해유기물질인 phenanthrene과 함께 glucose, hexadecane의 미생물 분해 반응식을 실제로 계산하였다. 예측된 총괄반응식을 이용하여 미생물 수율, 산소 요구량, 질소 요구량, 무기화율 등의 정보를 얻을 수 있었으며, 이는 오염된 지하수/토양의 생물복원 공법 설계 및 자연정화평가 등에 유용하게 적용될 수 있을 것으로 기대한다.

• 식물병연구
• /
• 제6권1호
• /
• pp.27-33
• /
• 2000

심하게 이병된 배추포장내 무사마귀병균의 수직분포를 보면 토양의 심도가 깊어질수록 무사마귀병균의 밀도는 급격히 감소하였으며 무사마귀병균의 97%가 지하 5cm 이내의 표토에 분포하였고 지하 40cm 토양에서도 소량 검출되었다. 수평분포를 보면 무사마귀병균은 배추포기중심에 모여 있다기보다는 전 포장에 골고루 분포하고 있어서 한곳에 몰려 분포하는 현상은 발견되지 않았다. 평창의 23개 배추지역의 무사마귀병균의 밀도는 1$\times$$10^4$포자/g 토양 이하의 밀도가 낮은 곳에서부터 $10^{6}$ 토양이상의 밀도가 높은 포장까지 폭넓게 분포하고 있었다. 작물을 재배하기 않은 처녀지 토양은 밀도가 $10^4$토양 이하로 극히 낮거나 전혀 검출되지 않았으며 심하게 이병된 배추밭의 밀도는 $10^{5}$/g 토양이상으로 대단히 높았다. 건전 배추밭과 배추 이외의 타작물을 재배하고 있는 포장내 밀도는 이보다 상당히 낮아서 심고 있는 작물에 따라서 토양내 무사마귀병균 밀도에 큰 차이가 있었다 작부체계별 밀도분포를 보면 다소 예외는 있으나 배추, 무 등의 기주작물을 연작한 곳일수록 밀도가 높게 나타났으며, 약초, 옥수수, 메밀, 기타 채소 등 비기주작물을 재배한 곳일수록 무사마귀병균의 밀도가 낮은 곳이 많았다. 배추, 무 등의 기주작물을 연작하면 토양내 무사마귀병균의 밀도는 점차 상승하는 경향이었고 반면에 당귀, 메밀 등 비기주작물로 윤작한 포장의 밀도는 급격히 감소하는 경향이어서 무사마귀병균의 토양내 생존은 작부체계에 의해 크게 영향을 받고 있는 것으로 나타났다. 본 연구에서 사용한 개량형광염색방법은 기존의 방법에 비해 토양내 휴면포자의 식별이 보다 용이해졌을 뿐만 아니라 그 검출효율도 증진되었고 조작이 간편하여 큰 숙련없이 밀도를 측정할 수 있어 향후 토양내 무사마귀병균의 동태를 연구하는데 유용하게 이용될 수 있을 것으로 생각된다.다.

• 한국지반공학회논문집
• /
• 제18권1호
• /
• pp.133-140
• /
• 2002

인산석고(phosphogypsum)는 인산비료 생산과정에서 발생되는 부산물로, 주요성분은 이수석고$(CaSO_4.2H_2O)$가 대부분이고 여기에 인$(P_2O_5)$, 불소 $(F_-)$와 유기물질 등으로 이루어져있다. 전세계적으로 인산석고는 약 15,000만톤정도 발생되고 있으며, 국내에서는 약 157만톤/년이 발생되고 있다. 본 연구는 폐기물 매립장의 일일 및 중간복토재로서 인산석고의 활용성을 분석하였다. 이를 위하여 입도분석, 비중, 연경도, CBR, 투수시험, 용출시험과 우수배제 시험등 일련의 실험을 실시하였다. 실험결과, 인산석고 혼합과 층별 조건에서 CBR값은 6.2~6.3%, 투수계수는 $\alpha$ $\times10_{-5}~10_{-6}cm/sec$로 나타났고, 용출시험결과, 관련법에서 요구하는 기준 값이하로 나타났으며, 우수배제시험결과에서 인산석고 혼합토의 우수배제율이 일반화강토와 비슷하게 나타났다. 따라서, 인산석고를 일일 및 중간복토재로 활용하는 것이 유용할 것으로 판단된다.

• 한국초지조사료학회지
• /
• 제11권1호
• /
• pp.1-5
• /
• 1991

Tall fescue(Festuca amndinacea Schreb.) is a productive pasture grass that is widely adapted to the soil and climate of Korea. It is regarded, however, as relatively low in palatability and nutritive value. On the other hand, Italian ryegrass(lo1ium rnultz$om Lam.) is highly nutritious and palatable, but is essentially weak in cold tolerance. Numerous investigators have succeeded in producing hybrids between Lolium spp. and Festuca spp. but no improved varieties have resulted. Therefore, intergeneric hybridization of Italian ryegrass with tall fescue is employed in 1984 to improve the adaptive and cold resistance quality of Italian ryegrass. In the mean time, F1-hybrid plants obtained by crossing Italian ryegrass x tall fescue were observed in open field. The results are summarized as follows: 1. Leaf-size and silica cell hair were intermediate between the types of parents but the shape of auricle tended to show Italian ryegrass and auricle-cilia to show tall fescue. 2. Roots of $F_1$-hybrid plants were mainly distributed at top soil and did not produced florescence material. 3. Head type of hybrids was intermediate between the types of parents but ray length was somewhat less than the length of tall fescue ray. Typical Italian ryegrass or tall fescue-like phenotypes were not observed. 4. Anthers of $F_1$-hybrid plants were formed but pollen were not formed. Even though pollen were formed, they were all empty. 5. Hybrid plants were more winterhardy and summer persistency than Italian ryegrass. They showed a equivalent growth to Italian ryegrass in spring and to tall fescue in summer. 6. Chromosome of $F_1$-hybrids was allopolyploid(2n=4~=28) and all $F_1$-hybrid plants were sterile.