• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.277-278
• /
• 2009

The building that supply tidal and splash zone was constructed near Seamangeum Gate Bridge. The specimens that will be tested for maintenance of gate bridge were exposed on the tidal and splash zone, totally about 650(Fig. 1). The characteristics of strength, salt penetration profile, field application of surface repair material and section recover material will be acquired by periodical test. The program was developed to obtain optimal maintenance strategy of gate bridge as a marine concrete structure and to deposit experimental data, lab. test result, field test result, on its D/B. On this paper, we hope to introduce two years exposure data as compressive strength, the modulus of elasticity, the modulus of dynamic elasticity, field adoption of repair and recover materials. As briefly speaking the results, possion's ratio, elasticity, strength was general, but the recover materials have some problems. There was crack between concrete and recover material and delamination figures.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2004.05a
• /
• pp.86-89
• /
• 2004

Recently polymer arresters are being used widely but we don't have appropriate long term characteristics test methods. Therefore we need to develop special test facility to evaluate long term reliability of polymer arresters. It's polymeric housing can be degraded by environmental stress and the interface between housing and inner module can be affected by moisture absorption. This moisture absorption can cause leakage current and tracking in the interface. We developed multi stress accelerated ageing test facility to simulate field conditions including UV, temperature, humidity, voltage, salt fog and rain. In addition, we carried out field exposure test at the outdoor test yard and characteristics analysis of field operated specimens to evaluate accelerating factor of this accelerated aging test.

• Proceedings of the KIEE Conference
• /
• 1996.07b
• /
• pp.847-849
• /
• 1996

As the power demands increases, one of the most important data is inside electric field of equipment in designing of insulators ami insulated wire for EHV distribution line. So far finite element analysis method is widely used to calculate this electric field. However as the shape of insulator becomes complicated, it is difficult in producing the mesh which suitable the shape. Especially, we have many difficulty that produce dense fine mesh only where the electric field is concentrated. Therefore in this paper, we perform the each conditional analysis of electric field using the Maxwell 3D Simulator to recover this defects. And we try to analyze electric field through the conventional 2 dimensional and 3 dimensional analysis in case of salt contamination on the surface of a insulator.

• Journal of Plant Biotechnology
• /
• v.29 no.4
• /
• pp.247-252
• /
• 2002

The combination of radiation technique with an in vitro culture system was initiated to develop salt tolerant rice. We established an in vitro culture system to select tolerant lines against salt stress. NaCl tolerant cell lines were selected from the callus irradiated with gamma ray on N$_{6}$ medium with 1.5% NaCl and 2 mg/L 2,4-D. Regenerants (M$_1$) were obtained from the tolerant callus which was cultured for 30 days auxin-free medium. The M$_2$seeds were harvested from M$_1$plants on an individual plant basis. Thirty seedlings from each 450 M$_2$lines were transplanted in a field and total 5,000 M$_3$lines were harvested with an average 90 percent of fertile grain. M$_3$lines were utilized for selection of salt tolerance. Salinity-tolerant lines (225) were selected among 5,000 M$_3$lines. Of the 225 lines tested, the morphological traits of two lines (120-10 and -11) were far superior to control (Donagjinbyeo) in agromomic traits such as plant height, root length and no. of roots. Control and tolerant lines were analyzed by RAPD markers. Three polymorphic bands were presented in only tolerant lines, demonstrating a genetic difference between control and the tolerant lines. Such tolerant lines could be used as genetic resources to improve salt tolerance.e.

• Journal of the Korea Institute of Building Construction
• /
• v.22 no.6
• /
• pp.553-564
• /
• 2022

Concrete is a representative composite material that shows excellent performance in the construction field. However, it is a brittle and nonhomogeneous material and exhibits weak behavior against bending and tensile forces. To compensate for such weakens, fiber reinforcement has been utilized, and steel fiber has been recognized as one of the best material for such purpose. However, steel fiber can seriously affect the durability of concrete exposed to the marine environment due to the corrosion caused by chlorine ions. This study intended to evaluate the mechanical performance of steel fiber reinforce concrete during and after repeated wet/dry cycles in salt solution. According to the experimental results, there was no reduction in the relative dynamic modulus of concrete during the repeated wet/dry cycles in salt solution for 37 weeks. Flexural strength was not decreased after completion of repeated wet/dry cycles in salt solution. There was no sign of corrosion in steel fibers after visual observation of fractured surface. However, the flexural toughness was decreased, and this is because about half of the concrete specimen showed failure before reaching the maximum displacement of 3 mm. Although repeated wet/dry cycles in salt solution did not cause cracks in concrete through corrosion of steel fibers, specific attention is required because it can reduce flexural toughness of steel fiber reinforced concrete.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.316-316
• /
• 2017

The objective of this study is to estimate quantitatively soil salinity and soil loss at upland soils in agriculture land region in Saemangeum reclaimed land on the south Korea coasts. Soil loss and soil salinity are the most critical problem at reclaimed tidal saline soil in Korea. The several thematic maps of research area such as land cover map, topographic and soil maps, together with tabular precipitation data used for soil erosion and soil salinity calculation. Meteorological data were measured directly as air temperature, wind speed, solar radiation, and precipitation. The experiment was conducted 2% sloped lysimeter ($5.0m{\times}20.0m$) with 14 treatments and it were separated by low salinity division (LSD) and high salinity division (HSD) install. The cation content in ground water increased during time course, but in the case of land surface water the content was variable, and $K^+$ was lower than that of $Na^+$ and $Mg^{2+}$. At the LSD under rainproof condition, the salinity was directly proportional to soil water content, but at the HSD the tendency was no reversed. In condition of rainproof, the amount of soil salinity was higher at the HSD than at the LSD. Positive correlation was obtained between the soil water content and available phosphorous content at the rainfall division, but there was no significance at the surface soil of the rainproof division. Sodium adsorption ratio and anion contents in soil were repressed in the order of vinyl-mulching > non-mulching > bare field. According to the result of analyzing soil loss, soil loss occurred in a vinyl-mulching, a non-mulching and a bare field in size order, and also approximately 11.2 ton/ha soil loss happened on the reclaimed land area. The average soil loss amount by the unit area takes place in a non-mulching and bare field a lot. Our results indicate that soluble salt control and soil erosion are critical at reclaimed tidal saline soil and the results can provide some useful information for deciding management plans to reduce soil loss and salt damage for stable crop production and diverse utilization or cultivation could be one of the management options to alleviate salt damage at reclaimed tidal saline soil in Korea.

• Korean Journal of Food Science and Technology
• /
• v.31 no.2
• /
• pp.368-374
• /
• 1999

This study was designed to investigate effects of pulsed electric field (PEF) treatment on physiological changes of microbial cells, using domestically fabricated pilot scale PEF device. The effect of non-thermal PEF treatment on physiological characteristics of microorganisms was determined by salt resistance, the amount of UV absorbents, cell staining, recovery rate of defected cells, and changes in structure of cell membrane. Salt resistance of Escherichia coli, Bacillus subtilis and Rhodotorula minuta was examined after PEF treatment at 40 kV/cm, 84 pulse, $10{\mu}s$ pulse duration. Approximately $1\;log_{10}$ cell number of viable microorganisms was decreased by addition of salt. PEF treatment significantly increased the amount of UV absorbents at 260 and 280 nm because of leakage from damaged cell membrane by PEF treatment. Although three kinds of microorganisms treated by PEF were difficult to be observed due to their cell membrane damage, untreated cells were clearly observed by a microscope. PEF-treated R. minuta was not stained by methylene blue due to cell membrane defect. When E. coli, B. subtilis and R. minuta were cultured after PEF treatment, they showed 5, 4, and 8 hr longer lag phase, respectively, compared to control, but growth rates were not affected.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.13 no.1
• /
• pp.29-35
• /
• 1987

Purely synthesized L-ascorbic acid 2 phosphate Mg salt (1 AsA PMg) improved the weak point of ascorbic acid which is easily decomposed in water solution. This compound is hydrolyzed with phosphatase of skin to corresponding ascorbic acid giving Vitamine C activities. The buffer solution of potassium acetate 0.5% and citric acid 0.005% and the sodium sulfite respectively showed good stabilizing effect of the AsA PMg solution. Compared to the other ascorbic acid derivatives the good solubility of AsA PMg gives broad application to cosmetic field.

• Journal of the Korean Society of Tobacco Science
• /
• v.8 no.1
• /
• pp.49-56
• /
• 1986

To obtain the information of low chlorine leaf production, the chlorine content of the soil and cured leaf in Burley tobacco growing area was investigated. The results obtained are as follows. 1. The chlorine concentration in soil at transplanting time in Kwang-ju growing area was higher than in Jeon-ju(1983), and paddy field sell showed higher concentration of chlorine than upland field in Jeon-ju(1984). The chlorine concentration in soil was different between years, locations, and cultivated land (paddy field and upland field), but the concentration, on the whole, was under the levels that might effect the leaf quality. 2. The chlorine concentration In soil was highest around todays after transplanting, and after harvesting, the concentration decreased to half of transplanting time. 3. The distribution of chlorine through the parts of tobacco plant showed remarkable difference between years, locations, cultivated land and growing stages. 4. There was significant positive correlation between chlorine concentration in top soil and chlorine content of cured leaf. 5. Chlorine content of cured leaf in Kwang-ju area(1.79%) was higher than that of Jeon-ju area(O.79%), relatively. 6. It was considered that the accumulation of salt from the sea by sea. wind did not main factor of high leaf chlorine content in seaside district.

• Geophysics and Geophysical Exploration
• /
• v.15 no.2
• /
• pp.66-74
• /
• 2012

This paper presents development of a three-dimensional marine controlled-source electromagnetic (mCSEM) modeling algorithm and its application to a salt and reservoir model to examine detectability of mCSEM for a reservoir under complex subsurface structures. The algorithm is based on the finite difference method, and employs the secondary field formulation for an accurate and fast calculation of modeling responses. The algorithm is verified for a two-layer model by comparing solutions not only with analytic solutions but also with those from other 3D modeling algorithm. We calculate and analyze electric and magnetic fields and their normalized responses for a salt and reservoir model due to three sources located at boundaries between a salt, a reservoir, and background. Numbers and positions of resistive anomalies are informed by normalized responses for three sources, and types of resistive anomalies can be informed when there is a priori information about a salt by seismic exploration.