• KCI Concrete Journal
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• v.13 no.1
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• pp.3-9
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• 2001

This research concerns the effect of kaolin as material of cement admixture. which has the advantage of low price and high adaptability. Kaolin, a kind of soil, is well known as a raw material of pottery. which is widely scat-tered on the earth (especially in Korea). This research shows the method and process for activating kaolin to have the properties of a cement admixture through experiment. In the experiments, kaolin is baked in high temperature and then cooled suddenly to be activated. The temperature zone and time span, on which kaolin is activated are examined. The research looks over the effect of the activated kaolin based on several criteria regarding to chemical and physical characteristic of general admixtures. The results of this research are as follows; kaolin start activation at the temperature above 50$0^{\circ}C$ and make ends of activation at the temperature below 95$0^{\circ}C$ and there was little effect by the change of duration. It is concluded that compressive strength can be increased by putting activated kaolin in the concrete and the activated kaolin is good for water resistance and anti-chemical , and that it is effective for protecting the leakage of hazardous article like Cl- and for protecting damage by an organic salt like acid. The activated kaolin of proper temperature and time is effective in compressive strength, salt resistance and acid resistance. The adaptability of activated kaolin as a cement admixture was shown through this research.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.972-978
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• 2002

Streptomyces sp. AD001 is a Gram-positive soil actinomycetes secreting an uncharacterized 2,4-dichlorophenol (DCP) oxidizing enzyme, whose activity is similar to the previously known Actinomycetes lignin-peroxidase (ALiP). This extracellular peroxidase was purified from Streptomyces sp. AD001 as a single protein band on an SDS-PACE by ammonium sulfate fractionation, Q-sepharose, concanavalin A, and Bio-Gel HTP column chromatographies. The molecular mass of the purified peroxidase was determined by SDS-PAGE to be 45.2 kDa, and 49.7 kDa with MALDI-TOF-MS, respectively. The highest level of peroxidase activity was observed at pH 7.5 and $30^{\circ}C$. The amino terminal sequence of the purified peroxidase (G-E-P-E-E-G-N-V-D-G-T-L) showed no significant homologies to my known proteins, suggesting that Streptomyces sp. AD001 may secrete a novel kind of bacterial peroxidase Initial rate kinetic data of the 2,4-DCP oxidation were best modeled with a random-binding bireactant system.

• Journal of Korea Soil Environment Society
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• v.3 no.1
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• pp.31-44
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• 1998

The geochemical experiments were carried out to investigate a removal effect of heavy metals in abdndoned metallic mine wastes, and to conceive a treatment techniques of them. In order to prevent contamination, experiment appature was made of acrylic acid resin and polyethylene which resist to acid and alkali. Experiment models are devided into four groups based on the system environments, distribution patterns and a kind of filling materials. The first group is background model(model I ) which is filled with waste only and opened to air. The second one is four layer group which is subdivided into two models, opened and closed systems, and the third mix group which is subdivided into three models based on mixing ratio of filling materials and system environment like a layered group. The forth is composed of two layer model, lower one composed of waste and upper one limestone chips. Solution drained from Model Ishows a high contents of heavy metals on the all terms of experiments. Among the models, however, the closed mix model V and Ⅶ show the most effective removal of heavy metals liberated from wastes. Models having different mixing ratios of filling materials on closed systems does not affect in heavy metal removal effect. But, the distribution patterns of filling materials affect very much on removal effect of heavy metals. The closed models with same constitution ratios and distribution patterns of filling materials show more and less effective removal to the open models.

• Structural Engineering and Mechanics
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• v.78 no.1
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• pp.53-66
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• 2021

The determination of the damage index to reveal the performance level of a structure can constitute the seismic risk generalization approach based on the parametric analysis. This study implemented this concept to one kind of civil engineering structure that is the concrete gravity dam. Different cases of the structure exhibit their individual responses, which constitute different considerations. Therefore, this approach allows the parametric study of concrete as well as soil for evaluating the seismic nature in the generalized case. To ensure that the target algorithm applicable to most of the concrete gravity dams, a very simple procedure has been considered. In order to develop a correlated algorithm (by response surface methodology; RSM) between the ground motion and the structural property, randomized sampling was adopted through a stochastic method called half-fractional central composite design. The responses in the case of fluid-foundation-dam interaction (FFDI) make it more reliable by introducing the foundation as being bounded by infinite elements. To evaluate the seismic generalization of FFDI models, incremental dynamic analysis (IDA) was carried out under the impacts of various earthquake records, which have been selected from the Pacific Earthquake Engineering Research Center data. Here, the displacement-based damage indexed fragility curves have been generated to show the variation in the seismic pattern of the dam. The responses to the sensitivity analysis of the various parameters presented here are the most effective controlling factors for the concrete gravity dam. Finally, to establish the accuracy of the proposed approach, reliable verification was adopted in this study.

• Journal of the Korean Geosynthetics Society
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• v.13 no.1
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• pp.53-61
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• 2014

Sea gives us a lot of benefits and one of them is a role of transporting goods easily by ship. Accordingly the industrial area or the container yard is constructed either on the low sea or near the sea. Sea dredging ground is made by pumping them using dredge pump to the inside of embankment after dredging undersea soils. The dredging ground after pumping is in the slurry state but as time goes, consolidation by the own weight happens and evaporation happens at the surface of dredging ground. The evaporation causes the crest layer in the upper side of dredging ground. Under the crest layer there is still a soil of slurry state which has just little bearing resistance. This kind of characteristics makes it difficult to get a exact bearing capacity using the equations proposed until now. In this study we have performed simultaneously both the field loading tests and the cone penetration tests on the sea dredging ground. From the result of field tests, new experimental equation for the ultimate bearing capacity has been proposed. If we use the new equation, it is believed that some design of sea dredging ground could be more accurate.

• Applied Biological Chemistry
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• v.11
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• pp.43-47
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• 1969

With an attempt to obtain a glucose isomerizing enzyme producing microorganism, one hundred and thirty-three strains of microorganism were isolated from soil samples. After screening, a strain K-17 which belonging to actinomyces family, was finally selected. Using this strain of K-17, sugars produced from glucose by the reaction of sugar isomerizing enzyme were tested with paper chromatography. Only a kind of resulting sugar, fructose, was detected from enzyme reaction sample and other sugars were never detected. By these results, the enzyme produced by strain K-17 is classified as a glucose isomerase.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.535-541
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• 2004

For housing estate of a new administrative capital city, Noise reduction method is a important design factor. As measuring a noise level of traffic noise according to separation from road, it can be created a quite housing estate. Analyzing of merits and demerits in sound barrier walls and tunnels can be proposed environment friendly soundproofing facilities. Number of measurement was performed to know what kind of layout of housing estate is good for noise reduction. Through this measurement, ㄷ shaped layout or parallel layout has the advantage of sound insulation rather than right angled layout. In this case (ㄷ shaped layout or parallel layout) buildings neighboring to the road should be designed to insulate sound. Evergreen trees should be planted between housing estate and road more than 30m (at least 7～8m) in order to reduce noise and have masking effects. If broad-leaved trees are planted more than 30m, approximately 10dB noise is reduced and 2～4dB if 7～8m. Roads in the estate should be designed considering pedestrians first, and special roads for moving and ambulance should be designed as skew road, if possible. The result shows that 15$^{\circ}$-sloped‘S’road reduces 1～2dB noise and 30$^{\circ}$-sloped road reduces 4～7dB. If noise barrier is inevitably installed, it should be designed to go well wit neighboring environment so as to install Environment Friendly Noise Barrier using materials and trees including wood and soil. Through this study the results are used to guideline for construction of environment friendly housing estate

• Journal of Korean Society of Forest Science
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• v.75 no.1
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• pp.1-18
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• 1986

This study was initiated to estimate productivity of Quercus variabilis stand. However the practical objective of this study was to provide some information to establish the basis of selecting the suitable site for Quercus variabilis. The productivity measured in terms of DBH, height, basal area and stem volume was hypothesized, respectively, to be a function of a group of factors. This study considered 32 factors, 20 of which were related to the forest environmental factors such as tree age, latitude, percent slope, etc. and the rest of which were related to soil factors such as soil moisture, total nitrogen, available $P_2O_5$, etc. The data on 4 productivity measurements of Quercus variabilis growth and related factors cited were collected from 99 sample plots in Kyeongbook and chungbook provinces. Some factors considered were, in nature, discrete variables and the others continuous variables. Each kind of factor was classified into 3 or 4 categories and total numbers of such categories were eventually amounted to 110. Then each category was treated as an independent variable. This is amounted to saying that individual variable was treated a dummy variable and assigned a value 1 or 0. However the first category of each factor was deleted from the normal equation for statistical consideration. First of all, each of 4 productivity measurements of Quercus variabilis growth was regressed and, at the same time, those 110 categories. Secondly, the partial correlation coefficients were measured between each pair of 4 productivity measurements and 32 individual foctors. Finally, the relative scores were estimated in order to derive the category ranges. The result of these statistical analyses could be summarized as follows: 1) Growth measurement in terms of height seems to be a more significant criterion for estimation of productivity of Quercus variabilis. 2) Productivity of forest on stocked land may better be estimated in terms of forest environmental factors, on the other hand, that of unstocked land may be estimated in terms of physio-chemical factors of soil. 3) The factors that a strongly positive relation to all growth factors of tree are age group, effective soil, soil moisture, etc. This implies that these factors might effectively be used for criteria for selecting the suitable site for Quercus variabilis. 4) Parent rock, latitude, total nitrogen, age group, effective soil depth, soil moisture, organic matter, etc., had more significant category range for tree growth. Therefore, the suitable site for Quercus variabilis may be selected, based on this information. In conclusion, the above results obtained by the multivariable analysis can be not only the important criteria for estimating the growth of Quercus variabilis but also the useful guidance for selecting the suitable sites and performing the rational of Quercus variabilis forest.

• Korean Journal of Environment and Ecology
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• v.23 no.4
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• pp.333-345
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• 2009

Carpinus laxiflora communities are known as the climax forest community of the temperate zone of Korea. There are three Carpinus laxiflora communities in Seoul. The purpose of this research is to analyze the characteristics of Carpinus laxiflora communities of Seoul and supply basic data for establishing of a management plan. The research sites are Sahmyook University, Mountain Dobong and Jinkwandong. This study considers investigation and the analysis of communities structure, soil characteristics and the growth increment of trees. As the result of study, we could know that the growth increment of the Carpinus laxiflora trees of Seoul is decreasing recently because of soil acidification and so on. Also the vegetation disturbance is increasing because of naturalized plant. Oak wilt disease has appeared in the oak forest around Sahmyook University that is the largest Carpinus laxiflora communities area in Seoul. For that reason the open gap was appeared in forest, and the spread of naturalized plants has been increasing in the gap. Furthermore, the Carpinus laxiflora trees are affected by the Platypus koryoensis which is a kind of oak wilt disease. And so, Unless there is a specific management plan, the survival of Carpinus laxiflora communities are uncertain in Seoul. Therefore the management plan of Carpinus laxiflora communities is necessary such as precise investigation, annual monitoring, etc. For the conservation of the Carpinus laxiflora communities, it is necessary to establish the management plan of the biodiversity for Seoul area.

• Korean Journal of Medicinal Crop Science
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• v.16 no.2
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• pp.94-99
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• 2008

Korean ginseng (Panax ginseng C.A. Meyer) is very difficult to obtain stable production of qualified ginseng roots because of variable stresses in soil environments. High salt concentrations in the ginseng nursery soil environment of Korea is one of important reducing factors for the stable production of quality ginseng. These studies were accomplished to identify the growth rate and production of ginsenoside from ginseng hairy root against NaCI. In the MS liquid culture, the highest contents and productivity of ginsenosides were appeared at 4 week after onset of the treatment of 0.1 M NaCI. And 0.24 M NaCI was more effective on the growth of ginseng hairy root under light condition than dark condition. Plants generally produce secondary metabolites in nature as a defense mechanism against pathogenic and insect attack. In this study, NaCI acts as a kind of stress as well as elicitor for production of ginsenosides.