• The Journal of Engineering Geology
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• v.21 no.2
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• pp.147-156
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• 2011

We conducted laboratory experiments to determine the physical and mechanical properties, and the failure behaviors, of cements for use as grouting material in a $CO_2$-injection borehole. Samples with lour different ratios of water to cement mass (0.4, 1, 2, and 3) were tested. The analyzed properties (porosity, sonic velocity, modulus, and compressive and tensile strengths) varied systematically as a function of the ratio of water to cement (w/c), showing a sharp change between w/c ratios of 0.4 and 1. Triaxial compression tests revealed a clear boundary between brittle and ductile failure depending on the w/c ratio and confining pressure. The present results can be utilized as input parameters for numerical models to understand the initial deformation and failure behavior of grouting cements in a $CO_2$-injection borehole.

• Korean Journal of Weed Science
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• v.16 no.4
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• pp.354-361
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• 1996

This study was conducted to evaluate the susceptibility of rice(Oryza sativa L.) cultivars to herbicide thiobencarb through the determination of protein patterns using SDS-PAGE. In both greenhouse and laboratory screening tests, IR 10198-66-2 and IR 9660-50-3-1 showed relatively tolerant response to thiobencarb, while IR 22, IR 31802-48-2-2-2 and IR 20656-R-R-R-6-1 were susceptible to it. The total protein content of susceptible cultivars markedly decreased as the thiobencarb concentrations increased, but tolerant cultivars such as IR 10198-66-2 and IR 9660-50-3-1 showed very slight changes suggesting that protein synthesis of susceptible cultivars may be inhibited by thiobencarb. The protein profiles of the tolerant cultivars were not much affected by thiobencarb treatment. However, the protein spots with molecular weights of 14.4 kD and 55 kD in the susceptible cultivar of IR 22 disappeared with the treatment of 3 ppm thiobencarb, indicating that differential susceptibilities of rice cultivars against thiobencarb can be attributed to their difference in protein metabolism affected by thiobencarb.

• Applied Biological Chemistry
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• v.49 no.4
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• pp.259-265
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• 2006

Effect of the fungicide mepanipyrim on the resistant and sensitive isolates of Botrytis cinerea was studied in vitro and also tested to control Botrytis rot of strawberry, cucumber and grape in the field. These isolates were selected by relative mycelial growth and spore germination on potato dextrose agar(PDA) incorporated with $100{\mu}g\;a.i./ml$ of benomyl and procymidone, respectively, compared to the unamended PDA. Mycelial growth of the selected resistant isolates was significantly inhibited by mepanipyrim but the inhibition rate was similar to other fungicides belong to benzimidazole or dicarboximide, although spore germination was not inhibited even by the higher concentration of mepanipyrim. When the benomyl and procymidone resistant isolates were inoculated to cucumber leaves, lesion development was significantly inhibited with application of $250{\mu}g\;a.i./ml$ of mepanipyrim but not with that of benomyl and procymidone. In addition, when $250{\mu}g\;a.i./ml$ of mepanipyrim was applied to strawberry, cucumber, and grape in the field, the control of Botrytis rot was significantly different from that of the untreated control(Duncan's multiple range test, p<0.05). The results suggested that mepanipyrim might be an alternative fungicide for the control of benomyl- and procymidone-resistant pathogens of Botrytis rot.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.987-992
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• 2007

충청북도 내의 농업용 저수지중 26개소를 선정하여 관개초기, 홍수기 및 비관개기의 연 3회에 걸쳐 저수율을 파악하고 채수를 실시하였다. 또한, 현장(수온, pH, DO, EC)과 실내 수질분석(Cd, As, Cn, Hg, 유기인, Pb, $Cr^{+6}$ PCB, ABS, COD, SS, TP, TN)을 실시하여 저수지의 오염도를 평가하였다. 저수율 측정결과, 홍수기(97%)가 관개초기(72%)나 비관개기(66%)보다 높게 나타났다. pH 값의 측정결과, 수질기준$(6.0{\sim}8.5)$을 만족하고 있는 저수지의 비율은 35%(9개소)의 낮은 값을 보였다. EC와 DO 및 SS농도의 측정결과, 거의 모든 저수지에서 수질기준을 만족하고 있었으며, COD, TN, TP농도 측정결과, 수질기준 만족도는 관개초기 100%, 홍수기 81%, 비관개기 65%로 나타나, 저수량이 많은 관개초기보다 저수량이 적은 비관개기에 질소와 인의 관리가 필요한 것으로 판단된다. 또한, 사람의 건강항목(CN, Hg, 유기인, PCB, Cd, 비소As, Pb, $Cr^{6+}$, ABS)은 모든 저수지에서 관개 초기, 홍수기 및 비관개기에 모두 수질기준을 만족하였다. 점오염원을 관리하기 위해서는 저수지 상류유역에 있는 마을하수도를 정비하고, 축산분뇨처리시설 등을 설치하여 저수지로의 유입부하량을 저감할 필요가 있다. 또한, 비점원오염을 관리하기 위한 대책으로서, 질소농도를 저감시키기 위해서는 용존성 성분을 제공하는 비료의 시용량을 줄여야하며, TP농도를 저감시키기 위해서는 강우시 입자성 인의 유출을 제어할 필요가 있으며, 이를 위해서는 비가 많이 오는 여름철에 나지(裸地)나 밭에 식생이나 멀칭(mulching) 등으로 토양침식을 방지할 필요가 있다.가용한 장 단기간의 관측자료와 물수지 분석 연산식의 추정치를 바탕으로 관측자료에 의한 물수지 분석을 수행하였다. 분석 결과로 산지 소하천 유역인 설마천 시험유역의 각 수문요소의 물이동간의 정량적인 값을 알 수가 있었으며, 앞으로 추가적이고 지속적인 수문모니터링이 운영되고 물순환 해석 모형에 의한 검증이 수행된다면 정량적인 물순환 관계를 규명할 수 있을 뿐만 아니라 이와 관련된 수문요소기술을 확보할 수 있을 것이다.절한 타협과 조정을 필요로 한다. 그러나 절제의 한계를 넘어선다고 생각되거나, 조정의 노력이 불가능하거나, 실패했을 때 폭력적인 행동으로 나타나게 된다. 리차즈(I.A Richards)는 분노와 공포는 일단 겉잡을 수 없는 경향이 있다고 하면서 오늘날 폭력에 대한 요구가 일상의 정서 생활에 있어, 억압을 통한, 빈곤함을 반영하고 있지 않은지 생각해봐야 할 것이라고 충고한다. 조성 가이드라인(안)을 제시하였다.EX>$\ulcorner$세종실록$\lrcorner$(世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와의 비교를 해보면 상 중 하품의 통합 9개소가 삭제되어 있고, $\ulcorner$동국여지승람$\lrcorner$(東國與地勝覽) 에서는 자기소와 도기소의 위치가 완전히 삭제되어 있다. 이러한 현상은 첫째, 15세기 중엽 경제적 태평과 함께 백자의 수요 생산이 증가하자 군신의 변별(辨別)과 사치를 이유로 강력하게 규제하여 백자의 확대와 발전에 걸림돌이 되었다. 둘째, 동기(銅器)의 대체품으로 자기를 만들어 충당해야할 강제성 당위성 상실로 인한 자기수요 감소를 초래하였을 것으로 사료된다. 셋째, 경기도 광주에서 백자관요가 운영되었으므로 지방인 상주지역에도 더 이

• Korean Journal of Microbiology
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• v.43 no.3
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• pp.193-200
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• 2007

Indoor airborne bacterial and fungal concentrations were examined at classrooms and corridors of 3 elementary schools in Ulsan. Airborne microorganisms were collected with an impaction-type air sampler using plate count agar and dichloran rose bengal chloramphenicol agar. During the semester, concentrations of bacteria ranged $168{\sim}3,887 MPN/m^3$ at classrooms and $168{\sim}6,339 MPN/m^3$ at corridors, while those of fungi ranged $34{\sim}389 MPN/m^3$ at classrooms and $91{\sim}507 MPN/m^3$ at corridors. The bacterial concentrations showed larger variations between situations and schools compared to those of fungi. When airborne bacteria were isolated and identified, 84% were observed as Gram-positive, and Micrococcus spp. was the most abundant group with 61% of tested isolates, followed by genus Staphylococcus with 10%. The Micrococcus spp. isolates, of which 75% were identified as M. luteus, appeared to be from human origins. The protective pigments and substantial cell wall of Micrococcus may provide selective advantage for their survival in the air. We also isolated and identified 15 genera of filamentous fungi. The most common culturable fungi were Cladosporium, Aspergillus and Penicillium, and these 3 genera were 69% of fungal isolates. Genus Stachybotrys, of which S. chartarum is a well known producer of many potent mycotoxins, was also detected from one of the schools. further systematic studies are necessary with an emphasis on species identification and mycotoxin production of isolated fungal genera, including Aspergillus, Penicillium, and Stachybotrys.

• Economic and Environmental Geology
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• v.43 no.4
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• pp.381-391
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• 2010

Probabilistic prediction methods of landslides which have been developed in recent can be reliable with premise of detailed survey and analysis based on deep and special knowledge. However, landslide susceptibility should also be analyzed with some reliable and simple methods by various people such as government officials and engineering geologists who do not have deep statistical knowledge at the moment of hazards. Therefore, this study suggests an evaluation chart of landslide susceptibility with high reliability drawn by accurate statistical approaches, which the chart can be understood easily and utilized for both specialists and non-specialists. The evaluation chart was developed by a quantification method based on canonical correlation analysis using the data of geology, topography, and soil property of landslides in Korea. This study analyzed field data and laboratory test results and determined influential factors and rating values of each factor. The quantification analysis result shows that slope angle has the highest significance among the factors and elevation, permeability coefficient, porosity, lithology, and dry density are important in descending order. Based on the score assigned to each evaluation factor, an evaluation chart of landslide susceptibility was developed with rating values in each class of a factor. It is possible for an analyst to identify susceptibility degree of a landslide by checking each property of an evaluation factor and calculating sum of the rating values. This result can also be used to draw landslide susceptibility maps based on GIS techniques.

• The Journal of Engineering Geology
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• v.15 no.1
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• pp.67-76
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• 2005

This paper presents the application of a neural network for prediction of the unconfined compressive strength from physical properties and schmidt hardness number on rock samples. To investigate the suitability of this approach, the results of analysis using a neural network are compared to predictions obtained by statistical relations. The data sets containing 55 rock sample records which are composed of sandstone and shale were assembled in Daegu area. They were used to learn the neural network model with the back-propagation teaming algorithm. The rock characteristics as the teaming input of the neural network are: schmidt hardness number, specific gravity, absorption, porosity, p-wave velocity and S-wave velocity, while the corresponding unconfined compressive strength value functions as the teaming output of the neural network. A data set containing 45 test results was used to train the networks with the back-propagation teaming algorithm. Another data set of 10 test results was used to validate the generalization and prediction capabilities of the neural network.

• The Journal of Engineering Geology
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• v.17 no.3
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• pp.359-365
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• 2007

Freezing and thawing cycle is one of the major weathering-induced factors in the mechanical weathering of the rock mass. This natural process accelerates rock weathering process by breaking down the parent rock materials and makes soil or weathered rock formation in a rock slope surface zone. It can also cause reduction of the shear strength in slopes. It is important to calculate the deterioration depth caused by freezing-thawing for a slope stability analysis. In this study, deterioration depths of rock slope due to freezing-thawing were calculated using the 1-D heat conductivity equation. The temperature distribution analysis was also carried out using collected temperature distribution data for last five years of several major cities in Korea. The analysis was performed based on the distributed rock types in study areas. Thermal conductivities, specific heats and densities of the calculation rocks are tested in the laboratory. They are thermal properties of rocks as input parameters for calculating deterioration depths. Finally, the paper is showing the calculated deterioration depths of each rock type slopes in several major cities of Korea.

• Journal of the Korean GEO-environmental Society
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• v.13 no.3
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• pp.29-37
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• 2012

This study is to find out the characteristics of the behavior of Geosyntehtic Reinforced Retaining Earth Wall(GRREW) through the laboratory experiment with the reduced-scale model, and to verify the effect of reinforcement by materials of GRREW. The loading tests after combining nonwoven geosynthetic, re-bar mesh nets and drainage blocks respectively among the components of the GRREW were performed in three cases of their slopes. In the cases of the behavior analysis including all of the components of the GRREW, the maximum horizontal displacement was generated 8.4mm at the location of 0.57H in the slope of 1:0.3; 3.8mm at the location of 0.57H in the slope of 1:0.6; 3.6mm at the location of 0.86H in the slope of 1:1.0. On average, the horizontal displacements of the GRREW were reduced by 83.8% against those of the original slopes. Lastly, seepage analysis and slope stability analysis were performed by modelling section of field, to confirm the effect of installation of drainage block in GRREW. We can confirm to compare increasing the slope safe factor and decreasing ground water in accordance with drainage blocks.

• Journal of Aquaculture
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• v.20 no.1
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• pp.7-13
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• 2007

The seed production of Ecklonia stolonifera Okamura was studied under laboratory conditions through the embryonic sporophyte stage and the field cultivation was conducted in eastern coast of Korea. The germination of zoospores occurred within 3 days and the growth of gametophytes was most rapid at $25^{\circ}C$ and $20\;{\mu}mol{\cdot}m^{-2}s^{-1}$. Sporophyte growth was highest at $20^{\circ}C$ and $20\;{\mu}mol{\cdot}m^{-2}s^{-1}$ and lowest at $25^{\circ}C$ and $80\;{\mu}mol{\cdot}m^{-2}s^{-1}$. In the nursery culture of E. stolonifera lasting for 2 weeks in January, the initial blade length of E. stolonifera (about $500\;{\mu}m$) grew to $526.3{\pm}176.0\;{\mu}m$ at water temperature of $12.05^{\circ}C$. The blade length and width reached their maxima in July, after which the ends of blade and stem began to degrade with the increase in water temperature. The degraded end of the blade started to regenerate in October, when water temperature began to decline. This species can be considered a potential candidate for aquaculture, increasing in the availability of raw material and aiding in recovery of seaweed bed.