• Korean Journal of Agricultural Science
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• v.15 no.2
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• pp.153-163
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• 1988

This experiment was carried out to obtain the thermophilic fungus producing amylase and to investigate properties of the amylase. The selected strain, L-11 was obtained from soil in the vicinity of a hot spring and identified as Mocor sp.. And then the conditions for enzyme production in wheat bran cultures and properties of the crude enzyme were investigated. Furthermore, the enzyme was purified and the characteristics of purified enzyme were studied. The results obtained were as follows: 1. On the wheat bran medium added 80-100% water, amylase was effectively produced by the selected strain, L-11 for 48 hrs incubation at $50^{\circ}C$. 2. When the crude enzyme solution of the strain L-11 was passed through DEAE-Sephadex A-50 column chromatography, two peaks having amylase activity were obtained, and one peak was that of the main enzyme (enzyme of B peak). 3. The purified enzyme (enzyme of B peak) was recognized as single protein band on polyacrylamide disc gel electrophoresis. 4. In the hydrolysis reaction of soluble starch by the enzyme of main amylase, oligosaccharides produced at early stage were maltose and maltotriose mainly and procedure of the reaction maltose amount of maltose and glucose was increased. 5. The strain L-11 was recognized as a special strain producing ${\alpha}-amylase$ mainly and scarcely glucoamylase. 6. The optimum pH, optimum temperature, pH stability, and temperature stability of ${\alpha}-amylase$ were pH 4.0, $60-65^{\circ}C$, pH 4.0-9.0, and below$70^{\circ}C$.

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.63-74
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• 2006

During the construction of circular underground pipe, the non-proper compaction along the pipe and the decrease of compaction efficiency have been the main problems to induce the failure of underground pipe or facility. The use of CLSM (controlled low strength materials) should be one of the possible applications to overcome those problems. In this research, the full-scaled field test and the numeric analysis using PENTAGON-3D FEM program were carried out for three different cases on the change of backfill materials, including the common sand, the soil from construction site, and the CLSM. From the full-scaled test in field, the use of in-situ CLSM as backfill materials reduced the vertical and lateral deformation of the pipe, as well as the deformation of the ground surface. The main reason for reducing the deformation would be the characteristics of the CLSM, especially self-leveling and self-hardening properties. The measured earth pressure at the surround of the corrugated pipe using the CLSM backfills was the smaller than the other cases, and the absolute value was almost zero. Judging from the full-scaled field test and FEM analysis, the use of CLSM as backfill materials should be one of the best choices reducing the failure of the underground pipes.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.4
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• pp.307-316
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• 2010

Complex terrain refers to irregular surface properties of the earth that influence gradients in climate, lateral transfer of materials, landscape distribution in soils properties, habitat selection of organisms, and via human preferences, the patterning in development of land use. Complex terrain of mountainous areas represents ca. 20% of the Earth's terrestrial surface; and such regions provide fresh water to at least half of humankind. Most major river systems originate in such terrain, and their resources are often associated with socio-economic competition and political disputes. The goals of the TERRECO-IRTG focus on building a bridge between ecosystem understanding in complex terrain and spatial assessments of ecosystem performance with respect to derived ecosystem services. More specifically, a coordinated assessment framework will be developed from landscape to regional scale applications to quantify trade-offs and will be applied to determine how shifts in climate and land use in complex terrain influence naturally derived ecosystem services. Within the scope of TERRECO, the abiotic and biotic studies of water yield and quality, production and biodiversity, soil processing of materials and trace gas emissions in complex terrain are merged. There is a need to quantitatively understand 1) the ecosystem services derived in regions of complex terrain, 2) the process regulation occurred to maintain those services, and 3) the sensitivities defining thresholds critical in stability of these systems. The TERRECO-IRTG is dedicated to joint study of ecosystems in complex terrain from landscape to regional scales. Our objectives are to reveal the spatial patterns in driving variables of essential ecosystem processes involved in ecosystem services of complex terrain region and hence, to evaluate the resulting ecosystem services, and further to provide new tools for understanding and managing such areas.

• Korean Journal of Agricultural Science
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• v.7 no.2
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• pp.131-144
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• 1980

The Linear Regression Model to extend the monthly runoff data in the short-recorded river was proposed by the author in 1979. Here in this study generalization precedure is made to apply that model to any given river basin and to any given station. Lengthier monthly runoff data generated by this generalized model would be useful for water resources assessment and waterworks planning. The results are as follows. 1. This Linear Regression Model which is a transformed water-balance equation attempts to represent the physical properties of the parameters and the time and space varient system in catchment response lumpedly, qualitatively and deductively through the regression coefficients as component grey box, whereas deterministic model deals the foregoings distributedly, quantitatively and inductively through all the integrated processes in the catchment response. This Linear Regression Model would be termed "Statistically deterministic model". 2. Linear regression equations are obtained at four hydrostation in Geum-river basin. Significance test of equations is carried out according to the statistical criterion and shows "Highly" It is recognized th at the regression coefficients of each parameter vary regularly with catchment area increase. Those are: The larger the catchment area, the bigger the loss of precipitation due to interception and detention storage in crease. The larger the catchment area, the bigger the release of baseflow due to catchment slope decrease and storage capacity increase. The larger the catchment area, the bigger the loss of evapotranspiration due to more naked coverage and soil properties. These facts coincide well with hydrological commonsenses. 3. Generalized diagram of regression coefficients is made to follow those commonsenses. By this diagram, Linear Regression Model would be set up for a given river basin and for a given station (Fig.10).

• Korean Journal of Heritage: History & Science
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• v.53 no.2
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• pp.222-241
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• 2020

The Taereung Royal Tomb from the Joseon Dynasty is the tomb of Empress Munjeong, the second queen of King Jungjong, and it contains various types of stone artifacts. All of these stone artifacts were constructed using coarse- to medium-grained biotite granite. The major types of deterioration of the stone artifacts are identified as surface weathering and biological contaminants. Exfoliation (145 sculptures), granular decomposition (138 sculptures), and repair materials (156 sculptures), along with biological contaminant algae (154 sculptures), lichen (165 sculptures) and moss (97 sculptures), have a high occurrence frequency. In particular, it is deemed that immediate conservation treatment is required, as biological deterioration (algae) represents the most serious condition (grade 3 or higher in 94% of all stones), and it is thought that exfoliation and granulation decomposition are required for long-term conservation management. As a result of equo -tip hardness and ultrasonic measurement, more than 70% of stones were found to have very weak physical properties. Through hyperspectral analysis, organisms were shown to inhabit more than 80% of the surface of burial mound stone artifacts, and P (phosphorus), S (sulfur), Cl (chlorine), and Ca (calcium) were detected in this area. This is because Taereung Royal Tomb has been exposed to the outdoors for hundreds of years and has been weathered by physical, chemical, and biological factors. Therefore, among the stone artifacts in the Taereung Royal Tomb, those with high physical weathering grades are considered to require consolidation to reinforce them physically. Since organisms are highly likely to cause stone damage, they must be removed via dry and wet cleaning. In addition, in order to delay the reoccurrence of organisms following conservation treatment, it is necessary to regularly clean up the soil that has flowed into the burial mound, and to monitor conservation conditions over the long term.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.2
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• pp.127-136
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• 2010

This study is aimed at reviewed and analyzed in order to suggest the improved plans related to natural monuments. The summary of this study is as followings; First, Replacing the current term 'cultural properties', which denotes the meaning of 'goods', we need to devise an new categorization that separates such properties into cultural heritage and natural heritage under the national heritage framework. Second, the designation criteria for natural monuments should be divided into the individual realm for animals and plants respectively, since they are not divided in the current Act. Third, the guidelines for naming of natural monuments should be established with the following new categories in accordance with the clear standards. Fourth, such imbalances require us to give priority to the relatively neglected types and areas. Fifth, as the big and old trees account for more than a half of the designated plants, it is necessary to search out new resources(wet plant communities, seashores, sand dune plant communities, etc.) such as geological resources, mineral springs, hot springs, and fossils that are in danger of completely being exploited and exhausted. While most of the designated animals are protected nationally, the existing designation system is required to protect habitats and breeding places for the systematic and efficient conservation. Sixth, as long as we need to preserve those historical and cultural resources for the future generations from national and global perspectives, we should enhance their values by designating them as natural monuments even though they are protected by other regulations such as the natural environment area. Seventh, as a result of the survey, we found that more budgets and experts in the local governments, more empowered organizations, more active public participation should be provided for the better Natural Monument management in Korea. Eighth, the Lap of Natural Heritage in the National Research Institute of Cultural Heritage needs to be developed to the Natural Heritage Institute to conduct the diverse activities such as researches, restoration, exhibition and education programs in a systematic and efficient way. Ninth and the last, major damages to natural monuments can be generally categorized into the artificial one and natural one, respectively. The artificial damages include toxics, soil covering, excessive humidity, fire, construction and management works, unlawful damages, fishing, oil spillage, etc, and the natural ones include lightning, storms(typhoons), heavy snowfalls, damage by insects and diseases, lack of prey, etc. This study will become meaningful in that it proposes specific measures for the improvement of the institutions, designation, and management of natural monuments on the basis of the comprehensive analysis on natural monuments. We wish to leave the other subjects related with this study to the future researches.

• Journal of Korea Water Resources Association
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• v.52 no.11
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• pp.917-929
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• 2019

Denitrification in streams is of great importance because it is essential for amelioration of water quality and accurate estimation of $N_2O$ budgets. Denitrification is a major biological source or sink of $N_2O$, an important greenhouse gas, which is a multi-step respiratory process that converts nitrate ($NO_3{^-}$) to gaseous forms of nitrogen ($N_2$ or $N_2O$). In aquatic ecosystems, the complex interactions of water flooding condition, substrate supply, hydrodynamic and biogeochemical properties modulate the extent of multi-step reactions required for $N_2O$ flux. Although water flow in streambed and residence time affect reaction output, effects of a complex interaction of hydrodynamic, geomorphology and biogeochemical controls on the magnitude of denitrification in streams are still illusive. In this work, we built a two-dimensional water flow channel and measured $N_2O$ flux from channel sediment with different bed geomorphology by using static closed chambers. Two independent experiments were conducted with identical flume and geomorphology but sediment with differences in dissolved organic carbon (DOC). The experiment flume was a circulation channel through which the effluent flows back, and the size of it was $37m{\times}1.2m{\times}1m$. Five days before the experiment began, urea fertilizer (46% N) was added to sediment with the rate of $0.5kg\;N/m^2$. A sand dune (1 m length and 0.15 m height) was made at the middle of channel to simulate variations in microtopography. In high- DOC experiment, $N_2O$ flux increases in the direction of flow, while the highest flux ($14.6{\pm}8.40{\mu}g\;N_2O-N/m^2\;hr$) was measured in the slope on the back side of the sand dune. followed by decreases afterward. In contrast, low DOC sediment did not show the geomorphological variations. We found that even though topographic variation influenced $N_2O$ flux and chemical properties, this effect is highly constrained by carbon availability.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.1
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• pp.57-70
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• 2009

Considerable advance has been made on research on effect of steel pipe Umbrella Arch Method (UAM) and mechanical reinforcement mechanism through numerical analyses and experiments. Due to long analysis time of three-dimensional analysis and its complexity, un-quantitative two-dimensional analysis is dominantly used in the design and application, where equivalent material properties of UAM reinforced area and ground are used, For this reason, development of reasonable, theoretical, quantitative and easy to use design and analysis method is required. In this study, both field UAM tests and laboratory tests were performed in the residual soil to highly weathered rock; field tests to observe the range of reinforcement, and laboratory tests to investigate the change of material properties between prior to and after UAM reinforcement. It has been observed that the increase in material property of neighboring ground is negligible, and that only stiffness of steel pipe and cement column formed inside the steel pipe and the gap between steel pipe and borehole contributes to ground reinforcement. Based on these results and concept of Convergence Confinement Method (CCM), two dimensional axisymmetric analyses have been performed to obtain the longitudinal displacement profile (LDP) corresponding to arching effect of tunnel face, UAM effect and effect of supports. In addition, modified load distribution method in two dimensional plane-strain analysis has been suggested, in which effect of UAM is transformed to internal pressure and modified load distribution ratios are suggested. Comparison between the modified method and conventional method shows that larger displacement occur in the conventional method than that in the modified method although it may be different depending on ground condition, depth and size of tunnel, types of steel pipe and initial stress state. Consequently, it can be concluded that the effect of UAM as a beam in a longitudinal direction is not considered properly in the conventional method.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.1
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• pp.49-50
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• 1982

The objective of this paper is to review the changes in fertilizer use pattern and to discuss some aspects of the fertilizer development in Korea. Fertilizer consumption in Korea have steadily increased to triple the application rates of N, P and K during the 15 years from 1965 to 1980, and Korea became one of the countries which apply fertilizers at the highest rate. The ratio of N: $P_2O_5$: $K_2O$ in fertilizer consumption changed from 55.4 : 31.4 : 13.1 in 1965 to 54.0 : 23.8 : 22.2 in 1980. It can be said that Korean farmers practise a balanced fertilization at least in view of fertilizer consumption as compared to other developing countries. However, differences in soil properties, crops, and climate varying as region were not reflected on fertilization. In the technological development of fertilizer, the chemical form and composition of the fertilizer as well as the suitability to the specific crops must be taken into consideration for the efficient use of fertilizers. Although organic fertilizers and manure are accepted as minor element suppliers, it is necessary to add minor elements into chemical fertilizers on the industrial process. Industrial waste may be used for the agricultural production as a measure of pollution control providing careful study on the waste.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.3
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• pp.200-206
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• 1985

This field experiment was undertaken to assess the effects of three levels of inclination ($10^{\circ},\;20^{\circ},\;and\;30^{\circ}$) and four rates of $N-P_2O_5-K_2O$ (0-0-0-, 14-10-10, 28-25-25, and 42-40-40kg/10a) on establishment, yield and quality, and botanical compositions of mixed grass-clover sward. This second part is concerned with the soil chemical properties, concentrations and uptake of mineral nutrients, and percent recovery and efficiency of NPK. The results obtained after a two-year experiment are summarized as follows: 1. The pH, exchangeable Mg and Na, and base saturation in the surface soils were decreased by increasing the grade of inclination, whereas organic matter and available $P_2O_5$ tended to be increased. However, the changes in the Ca content and equivalent ratio of $K\sqrt{Ca+Mg}$ were not significant. The pH, exchangeable Ca and Mg, and base saturation were reduced by increasing the NPK rate, whereas available $P_2O_5$, exchangeable K, and equivalent ratio of $K\sqrt{Ca+Mg}$ tended to be increased. 2. The concentrations of mineral nutrients in grasses and weeds were not significantly affected by increasing the grade of slope in hilly pasture, whereas the concentrations of N, K, and Mg in legume were the lowest with the steep slope, which seemed to be related to the low legume yield. The Mg concentrations of all forage species were below the critical level for good forage growth and likelihood of grass tetany. 3. The increase of NPK rate resulted in the increment of N, K and Na concentrations, and the decrease of Mg and Ca in grasses. The P concentration was increased with P application, but there were no differences in that among the P rates applied. It resulted also in a slight increase of K, and a decrease of Mg in legume, but the contents of N, Ca, and Na were not affected by that. On the other hand, it has not affected the mineral contents in weeds except a somewhat increase of N. The mixed forages showed a increase of N and K contents, a decrease of Ca and Mg, and a slight change in P and Na. 4. The percent recovery of N, P and K by mixed forages were greatly decreased by increasing the grade of inclination and NPK rate. They were high in the order; K>N>P. The efficiency of mixed NPK applications was decreased by that. The efficiency of mixed NPK fertilizers absorbed was slightly decreased by the increased rate of NPK, but it was not affected by the grade of inclination.