• Journal of Korean Society on Water Environment
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• v.40 no.2
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• pp.79-88
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• 2024

This study employed field measurements and biogeochemical analysis to examine the effects of seasonal conditions (e.g., temperature and precipitation) and human intervention (e.g., dam or weir construction) on the chemical composition of dissolved organic matter, flocculation kinetics of suspended particulate matter, and formation of the fluid mud layer on riverbeds. The results indicated that a water environment with a substantial amount of biopolymers offered favorable conditions for flocculation kinetics during an algal bloom period in summer; a thick fluid mud layer was found to be predominated with cohesive materials during this period. However, after high rainfall, a substantial influx of terrigenous humic substances led to enhanced stabilization of the particulate matter, thereby decreasing flocculation and deposition, and the reduced biopolymer composition served to weaken the erosion resistance of the fluid mud on the riverbed. Moreover, a high-turbulence condition disaggregated the flocs and the fluid mud layer and resuspended the suspended particulate matter in the water column. This study demonstrates the mutual relationship that exists between biogeochemistry, flocculation kinetics, and the formation of the fluid mud layer on the riverine area during different seasons and under varying hydrological conditions. These findings are expected to eventually help inform the more optimal management of water resources, which is an urgent task in the face of anthropogenic stressors and climate change.

• Journal of the Korea Institute of Building Construction
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• v.7 no.1 s.23
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• pp.99-106
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• 2007

Water leakage could be caused deterioration of environmental conditions, user condition, reduction of life span and long term safety in underground concrete structure. Many materials and construction method to repair on these problems have been developed, however, it is not proper to successful repair or raise problem of increasing repair cost However, there are many limitations as practical appraisal methods due to different view of reliability for test methods. Because, it was not enough that the technical objectivity could be lack and also application of environmental condition is inadequate. In this paper, we suggest varied test methods divided to appraisal for property of matter, construction, manufacturing, specification and maintenance, friendly environmental condition. It could be more practical as a objective standard considering various angles. In summery, it should be subdivided and differentiated to accomplish proper application and to select proper materials and construction method for repair even if the synthetical condition is very complicated.

• 보존과학연구
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• s.20
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• pp.139-154
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• 1999

We tested to obtain the excellent Epoxy resins on the property of matter. Existing Epoxy resins is tested to regulate the viscosity, color and hardening time etc. Benzen-ring structure of Bisphenol A type (AY 103) is replaced by Hydrogenated B.P.A type. And hardener is replaced by Polyoxyalkylene Amine. So we are developed into the two resins(L-30, L-40).To know if this Epoxy resins was fitted to repairing and restoration of stone cultural properties. Three kinds of Epoxy resins (AY 103, L-30, L-40) are tested on the artificial weathering test, freezing-melting test, exposure test etc. As a result of test, L-30 is less the discoloration than that of other Epoxy resins and was superior to the excellent property of matter.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.1
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• pp.33-40
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• 2018

The society for conservation of local historical properties in Korea originated in Japan. It was transplanted by Joseon Governor-General to represent their positions in the field of the conservations of the cultural properties. Also the society for conservation of local historic properties represented the positions of the provincial government office because the representatives of that societies were the chief of local government offices. At that time, the fundamental concept of the historical property conservations was not settled, so they accomplished the conservation activities as the necessary way for themselves.They often made a proposal about repairs for conservation of historical building and suggested a application for the national budget. And they contributed to carry out the repair works of the historical properties in the early Japanese colonial period. But they was usually used to invigorate the tourism and to publicize the regional characteristics through the historical properties. Although the societies were privately-managed as a matter of form, they were governmentally-managed as a matter of fact. It was the limits of the societies for conservation of local historical properties at that time.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.719-727
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• 2022

The soil physical and chemical properties are the main factors that influence plant productivity and soil fertility. Since 1999, South Korea has been conducting a survey on changes in the agricultural environment survey every four years. The purpose of the present study is to monitor the physical and chemical properties of soil in Chungcheongbuk-do. Soil samples were collected from the exact sites of the aforementioned environment survey, and land use and cultivated crops were also investigated. From a Pearson correlation analysis, it was found that the total carbon contents were most negatively affected by the soil depth. The bulk density of soil increased up to a depth of 40 cm but decreased to a depth of 60 cm. The porosity and moisture of soil generally decreased, but the porosity increased at a depth of 50 - 60 cm. Chemical properties of soil gradually decreased with an increase of the soil depth from 0 to 70 cm, but little change was observed in soil pH with soil depth. In addition, the organic matter contents of the soil at a depth of 30 cm or more were below the optimal range. The soil of Chungcheongbuk-do thus requires organic matter application as a whole, and correction of items that are partially out of the optimal range is necessary.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.87-88
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• 2011

High absorptance of lightweight aggregate make a hard product, work, quality management ect. for making low absorptance property, lightweight aggregate is coated by an organic matter and that way remarkably showed to decrease the absorptance by pre-study. but first, we would need a check to fit into the concrete which both fresh concrete and hardened concrete. In this study, mechanical property change of coated lightweight aggregate concrete was analysed by compared experiment with coated lightweight aggregate concrete and non-coated aggregate concrete.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1239-1241
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• 1993

This paper studies on the improvement of non-tracking property which is very important matter for developing polymer insulator. Non-Tracking property of silicon rubber used for polymer insulator was investigated by ASTM D 2303 according to Aluminium Hydrate filler. Furthermore other electrical and mechanical properties were estimated. The optimum amount of Aluminium Hydrate should be considered by following test results.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.4
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• pp.254-261
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• 2014

The scientific information between microbial activities and chemical properties of reclaimed tidal soil is not enough to apply for reclamation projects. This study was conducted to investigate the relation between chemical properties and microbial activities of reclaimed tidal lands located at western coastal area (25 samples from Nampo, Ewon, Sukmoon and Shihwa sites). Most of the reclaimed soils showed chemical characteristics as salinity soil except Nampo site. The major component influenced the salinity of reclaimed soil was identified as a sodium from the relationship between EC and exchangeable cation. With an increase in EC of soil, the population of mesophilic bacteria decreases whereas halotolerant and halophilic bacteria increases. The population of mesophilic bacteria increased with an increase in both organic matter and dehydrogenase activity. However, the population of halotolerant and halophilic bacteria decreased with an increase in organic matter. Based on the relation between chemical property and microbial activity of reclaimed tidal soil, electrical conductivity and organic matter as chemical properties of soil, population of mesophilic bacteria, halotolerant and halophilic bacteria and dehydrogenase activity as microbial activities could be the major parameters for reclamation process.

• 보존과학연구
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• s.21
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• pp.101-118
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• 2000

Stone cultural properties(pagoda, Buddhist statue etc.) is moved in original place for many reasons and restored after taking to pieces for structural safety. With the movement and restoration after taking to pieces, the cast iron is used for the sake of a fixation and horizontality. The stone cultural properties are spoiled the beauty and accelerated the weathering because of the corrosion product of cast iron. So we need to substitute for the improved property in all aspects. We are executed the corrosion test and inquired the property of material on the usable material for the shim of stone cultural properties. That is the Cast iron, Stainless steel, Titanium and Fiber Reinforced Plastics. In the result of the physical property and strength, the Stainless steel and Titanium was superior to the Cast iron. And the Stainless steel and Titanium was slower than the Cast iron in the corrosion velocity for the acid, salt and rain. If the shim is substitute the Stainless steel or Titanium for the Cast iron, the stone cultural properties are able to reduce the pollution of stone cultural properties by corrosion product and should not happen in the matter of stone pagoda.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.784-792
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• 2009

In this study, we investigated the unsuitable cases for the hierarchy of the curriculum in science 'teaching-learning lesson plan' which is on the web site of the each city's support center for teaching and learning and Seoul Science Park with a purpose of giving helpful data for science teachers at lessons. The investigation is limited to 'Three states of matter' unit for the 7th grade and the content elements used at analysis was the "state changes of matter", "molecule" and "molecular model". The case found for unsuitable case for the hierarchy of the curriculum was phase equilibrium, ice crystal theory, peculiar property of water, classification of solid, thermal energy and physical change at the "state changes of matter". While the "molecular model" showed molecular motion and density. On the other hand, no case was found at "molecule".