• Journal of environmental and Sanitary engineering
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• v.19 no.1
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• pp.8-16
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• 2004

Ground water samples were collected from residential, green" industrial, landfill and mining area and analyzed for 23 inorganics from March to October in 2002. The results are as follows; 1. The detection frequencies of inorganic materials such as As, Ba, B, Mo, Ca, Mg, Al, Cu, Fe, Mn, Zn, Na, K were 7.2∼77.1% which showed that these inorganics were detected in many ground waters. 2. The detection frequencies of 7 inorganics(Cd, Cr, Ph, Se, Sb, Be, Tl) were commonly low at ranging from 0.42 to 2.5%. These inorganics were contained in ground water partially. 3. Three inorganics such as Hg, Ni, Ag were not detected in any ground-water samples. 4. Compared to the other areas, ground water samples from landfill area contained greater concentration in many inorgainics and then showed higher levels in industral, residential, mining and green area in order. 5. Compared to noted concentrations of bottled water, inorganic minerals including Ca, Mg, Na, K related to taste were fluent in target samples. The results showed that the average concentrations of Mg, Na, K were 4.0 mg/l, 14.7 mg/l, 1.5 mg/l respectively. 6. The concentrations of inorganics such as Sb, Ba, Mo, Be, Tl, K in some ground water samples exceeded the water quality standards of WHO, the US and UK. Especially, Ba, Mo, K also showed relatively high detection frequencies so these inorganics need to be considered as analytes in Korea Drinking Water Regulation in further study.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.583-588
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• 2002

The purpose of the study is to evaluate fracture toughness on the Laser and the electron beam welded joints of high tensile steels (HT500, HT550, HT650) by using 3-point bend CTOD and Charpy impact test. WM (weld metal) CTOD tests have been carried out using two kinds of CTOD specimen, the Laser beam welding (108mm length, and 24mm width, and 12mm thickness) and the electron beam welding (l71mm length, and 38mm width, and 19mm thickness). WM Charpy impact specimen is a standard V-notch type, and the temperature of the experiment is changed from -45 to 20 degree of centigrade. FE-analysis is also performed in order to investigate the effect of stress-strain fields on fracture characteristics. Results of the standard V-notch Charpy test are influenced by strength mis-match effect and the absorbed energy vE depends on crack path, and The transition temperature of Laser beam welded joints is more higher than that of electron beam welded joints. Results of the 3-point bend test give low critical CTOD and the crack path is in the weld metal of al specimens. These results indicate fracture toughness characteristics of the welded joints and transition temperature of HT500 are similar both a Laser beam welded joint and an electron beam welded joint. But the fracture toughness and the transition temperature of the electron beam welded joints of HT550 and HT650 are higher than those o the Laser beam welded joints.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.384-389
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• 2002

This study was aimed to evaluate the weldability and optimize the welding conditions for flash butt welding of 780MPa grade steel applied to the automotive bumper reinforcement. And then the relationship between the welding conditions and the joint performance relating specifically to coil-joining steel would be established. The effect of welding conditions between flashing and upsetting process was elucidated. Microstructure observation of the joint indicated that the decarburized band was mainly changed with upsetting process. Width of HAZ was also related to the upsetting conditions rather than the flashing conditions. Generally maximum hardness at HAZ was correlated with $C_{eq}$ of steel and the empirical relationship was obtained to estimate the HAZ properties. Tensile elongation at the joint was usually decreased with increasing the initial clamping distance. Investigation of fracture surface after tensile and bending tests reveal that the origin of cracking at the joint was oxide inclusions composed of $SiO_2$, MnO, $Al_2$ $O_3$, and/or FeO. The amount of inclusions was dependent on the composition ratio of Mn/Si in steel. If this ratio was above 4, the amount of inclusions was low and then the resistance to cracking at the joint was enough to maintain the joint performance. It was obtained that the flashing process influenced the conditions for the energy input to establish uniform or non-uniform molten layer, while the upsetting conditions influenced the joint strength. Heat input variable during flashing process was also discussed with the joint properties.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.327-334
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• 2016

In order to compare phosphorus (P) behavior of livestock manure compost (LMC) and chemical fertilizer (CF) applied to the sea-reclaimed land soils, incubation experiments were conducted for five weeks. Four soils differing textural classes, sandy loam and clay loam, and electric conductivity (EC) value, high and low, were applied with CF and LMC. LMC was applied at the level of 0, 1, 2, and 3% on the soil weight basis and CF was applied at the same levels of P as LMC. The results showed that increase of P application rate of CF and LMC led to linearly increase available $P_2O_5$ and $0.01M\;CaCl_2$ extractable P contents regardless of soil texture and EC. However, 0.01M $CaCl_2$ extractable P from soil applied with CF was significantly higher than with LMC. Correlation analysis between $0.01M-CaCl_2$ extractable P and fractionated P by different extraction methods showed that $0.01M-CaCl_2$ extractable P positively correlated with KCl-P (soluble and exchangeable P) and HCl-P (Ca and Mg bound P). However, NaOH-P (Fe and Al bound P and organic P) and residual P was adverse. The amount of NaOH-P significantly influenced to the amount of 0.01M $CaCl_2$ extractable P of CF and LMC in the soils. The application of LMC at sandy loam soil could be carried out in the consideration of nutrient leaching and crop uptake.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.22-28
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• 2011

With the increasing cultivation of acid-loving plants such as blueberries, the artificial acidification of soils is frequently required. This research was conducted to determine the application rates of elemental sulfur (S) required in the soil acidification for blueberry cultivation. Laboratory incubation experiment was conducted to acidify three arable soils (pH 6-7) of different texture to pH 4.5-5.0 by the addition of varying amounts of elemental S. All rates of elemental S addition reduced soil pH, although the efficacy of acidification was related to the application rate and soil characteristics. pH reduction was slow in sandy loam soil, and the final equilibrium pH was obtained after 60, 43, and 30 days of incubation in sandy loam, loam, and silty clay, respectively. Although the final pHs obtained after 93 days of incubation were not significantly different among the three soils, the equilibrium pH was relatively higher in soil of higher clay content in the application rates of 1.5-2.0 g S $kg^{-1}$ soil. The estimated amounts of elemental S required in lowering pH to 4.5-5.0 were 0.59-1.01, 0.67-1.03, and 0.53-0.88 g S $kg^{-1}$ for sandy loam, loam, and silty clay, respectively. The lowest estimated amount of elemental S in the acidification of silty clay soil was attributable to the low organic matter content. For clay soils containing optimum level of organic matter, the application rates of elemental S should be much higher than those values estimated in this research. Soil acidification did not significantly increase the available concentrations of Ca, Mg and K. Extractable Cu and Zn was not greatly affected by the acidification, but extractable Fe, Mn, and Al in the acidified soils were higher than those found in non-acidified soils. Such increases in solubility are attributable to the dissolution of oxides and hydroxides of the elements.

• The Research Journal of the Costume Culture
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• v.13 no.3 s.56
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• pp.380-390
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• 2005

The effect of high purity chitosan was studied on its application to the natural dyeing using Rhusjara ica. In the dyeing experiment, examinations were introduced on the difference between the chitosan treated fabrics and chitosan untreated fabrics, and on the difference according to the type of mordanting agents and the mordanting methods. Dyeing was carried out for the chitosan treated and untreated fabrics under the conditions of non-mordanting and Al, Sn, Fe mordanting. As a result, we found that, in the case of cotton, chitosan untreated fabrics were not dyed enough, and the dyeing effect was not developed even though the mordanting was introduced. However, the chitosan treated fabrics developed excellent dyeing result even in the non-mordanting case. Through the results of cotton fabric dyeing, it was presumed that the dyeing affinity of the chitosan toward the Rhusjara ica, which prefer specific dyestuff (mainly black color), is selectively high. In the case of nylon, the dyeing effect is not developed easily under all conditions regardless of the chitosan treatment or the mordant treatment. It was inferred that a certain portion of the Rhusjara ica dyestuff made direct bonding with the functional elements in the nylon molecules without the help of the mordant. Through the results of nylon fabrics, it was presumed that some functional elements of the nylon molecules had selective affinity toward the specific colorant (mainly yellow color) of the Rhusjara ica.

• Journal of Environmental Science International
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• v.10 no.3
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• pp.201-208
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• 2001

To investigate the physio-chemical components and properties of aerosol particles in urban area sampling of aerosol particles was carried out in the campus of Hokkaido University, Sapporo, Japan, during snowfall. Aerosol particles were collected on millipore filter papers using a low volume air sampler. Their shapes, sizes and chemical components were analyzed by a SEM(Scanning Electron Microscope) and an EDX(Energy Dispersive X-ray). As a results, ice crystals of dendrite and column types were predominantly shown at mature and developing stage of snowfall intensity. The denerite and sector plate types of ice crystals were mainly originated from the sea but column types were come from soil. Scavenging effect by snowfall was greatly also shown at dendrite type ice crystals that embryo was fully developd. Al, Si elements were shown at high frequencies as compared with others. Na, Cl components were especially shown at high frequencies under the sea-breeze wind during snowfall. Anthropogenic aerosol particles had shown with irregular shapes and sizes, relatively. Mainly 3-7$\mu$m aerosol particles were abundant and coarse particles also could be seen during snowfall. Ca, Zn, Fe components mainly caused by spike tires from vehicles in winter season were dominant before snowfall, however the element S mainly caused by human activity was rich after snowfall. The pH values of snow in Sapporo city were higher than those at coastal area. The concentration of chemical components in aerosol particles was also affected by surface winds. Aerosol particles in urban area, Sapporo were mainly affected by human activities like vehicles and combustion with wind system. And their types were related with snowfall intensity.

• KOMUNHWA
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• no.60
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• pp.101-120
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• 2002

The floor tile on a coated green-glass was excavated from the Beobgwangsa Temple Site in the Pohang City. We analyzed using the MXRD, ICP-AES, EDXRF, TG/DTA and TIMS. As a result of microscope analysis, it was composed of quartz, feldspar and clay particl

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1262-1265
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• 2004

송전용량 증가를 위해 개발되어 최근 본격적으로 사용되고 있는 STACIR/AW 송전선은 송전용량의 증가에 따라 그 운전환경도 변화하여 연속사용온도의 경우, 기존 ACSR 전선의 90t에 비해 높은 $210^{\circ}C$로 규정 되어 있을 만큼 고온에서 운전되고 있다. 따라서 STACIR/AW 송전선은 이도설계와 그 운용에 있어서 운전 온도 상승에 따른 각별한 주의관리가 필요하다 실제 STACIR/AW송전선은 그 설계단계에서도 이와 같은 고온운전 환경을 고려하여 고온에서도 소정강도를 유지하는 내열 Al도체와 이도제어를 위한 낮은 열팽창 특성의 INVAR합금(Fe-35Ni계 합금)을 강선으로 하는 특화된 재료로 구성되어 있다. 그러나 이와 같은 재료 설계적 보완책에도 불구하고 실제 송전선은 전선의 자중, 철탑 간에 형성된 가설장력과 같은 다양한 응력이 고온환경에서 부하되는 복합 열화 상태에 노출되어 있고, 이것은 재료학적인 관점에서 크릴 변형 발생의 가능성을 높이고 있으나 이것에 대한 연구 또는 실험결과는 크게 미미한 실정이다. 본 연구에서는 STACIR/AW $410mm^2$ 송전선과 그 구성소재를 대상으로 $200^{\circ}C$, $300^{\circ}C$에서 장시간 열화한 후, 구성소재의 탄성계수, 열팽창계수 및 STACIR/AW전선의 크림변형 거동을 조사하여 열화에 노출된 STACIR/AW 송전선의 이도변화 거동을 규명하고자 하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.4
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• pp.342-349
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• 2009

This study investigated the growth characteristics of carbon nanotubes (CNTs) by changing a period of annealing time and a $C_{2}H_{2}/H_2$ flow ratio at temperature as low as $450^{\circ}C$ with inductively coupled plasma chemical vapor deposition. The 1-nm-thick Fe-Ni-Co alloy thin film served as a catalyst layer for the growth of CNTs, which was thermally evaporated on the 15-nm-thick Al underlayer deposited on the 50-nm-thick Ti diffusion barrier. The annealing at low temperature of $450^{\circ}C$ brought about almost no granulation of the catalyst layer, and the CNT growth was not affected by a period of annealing time. A study of changing the flow rate of $C_{2}H_{2}$ and $H_2$ showed that as the ratio of the $C_{2}H_{2}$ flow rate to the $H_2$ flow rate was lowered, the CNTs were grown to be longer With further decreasing the flow ratio, the length of CNTs reached the maximum and then became shorter. Under the optimized gas flow rates, we successfully synthesized CNTs with a uniform length over a 4-inch Si wafer at $450^{\circ}C$.