• Toxicological Research
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• v.22 no.1
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• pp.15-22
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• 2006

Many of endocrine disrupting chemicals induce effects via interaction with hormone receptors and responsive elements in target cells. We investigated endocrine disrupting effects of some food additives and contaminants including BHA, BHT, ethoxyquin, propionic acid, sorbic acid, benzoic acid, CPM, aflatoxin B1, cadmium chloride, genistein, TCDD and PCBs in yeast transformants expressing human steroid hormone receptors along with steroid responsive elements. The response limit of genetically recombinant yeast to $17{\beta}$-estradiol, testosterone and progesterone was $1{\times}10^{-16},\;1{\times}10^{-12}\;and\;1{\times}10^{-13}M$, respectively. BHT induced weak transcriptional activity in estrogen sensitive yeast, while BHA and sorbic acid interacted weakly with androgen receptor/responsive element. CPM induced transcriptional activities in all types of yeasts sensitive to steroid hormones. Zearalenone and genistein induced high transcriptional activation in estrogen sensitive yeast with relative potencies almost $10^8$ folds lower than $17{\beta}$-estradiol. TCDD induced transcriptional activation weakly in estrogen- and progesterone- sensitive yeasts. This study elucidated that recombinant yeast is a sensitive and high-throughput system and can be used for the direct assessment on chemical interactions with steroid receptors and responsive elements. Also, the present study raises the requirement of evaluation on the endocrine disrupting effects of BHT, BHA, sorbic acid, CPM and TCDD for their transcription activity in yeast screening system though weak in intensity.

• Analytical Science and Technology
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• v.13 no.2
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• pp.215-221
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• 2000

Analysis of fly ashes from the MSW incinerators was carried out using XRF, ICP-MS and ICP-AES. It was found that the major elements of fly ash were Ca, K, Na, Si, Al, S, Cl and O by the XRF analysis. The XRD spectra showed that the fly ashes were mainly consisted with the chlorides, hydroxides, carbonates and also oxides of former elements. For the determination of minor elements such as Zn, Pb, Cu, Cr, and Cd, we used ICP-AES and ICP-MS after microwave digestion and the results were compared with the result of XRF.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.2
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• pp.183-191
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• 1990

To check the possible transportation of gaseous air pollutants with the particles of yellow sand in the movement of air masses during the Yellow Sand Phenomenon, the concentrations of such air pollutants as TSP, $SO_2, CO, NO_x, O_3 and N-CH_4$, and wind wpeed were measured during the Yellow Sand Phenomenon (April 8 $\sim 10, 1990) and they were compared with those during the normal times in Korea. Meanwhile dust color of the samples during the Yellow Sand Phenomenon was the color of sand, that during the normal times was dark-brown. The concentrations of dusts; water soluble components, and metallic components of soil-originated elements during the Yellow Sand Phenomenon were higher than those during the normal times. While the metallic components in the dusts during the Yellow Sand Phenomenon were from soil-originated elements, those during the normal times were of both soiloriginated and sea-originated elements. The change of hourly concentrations of air pollutants showed bi-modal distribution during the two periods. Generally, the concentration levels of air pollutants during the Yellow Sand Period were higher than those during the normal times. Although similarity was observed in the primary sources, differences were observed in the dynamics of the secondary sources due to chemical reactions of the air pollutants during the two periods.

• Journal of Environmental Science International
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• v.12 no.10
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• pp.1043-1054
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• 2003

During the period from April to September 2002, the size distributions of ambient aerosol were measured at the coastal site at Hamduk in Jeju Island. Na$\^$+/, K$\^$+/, Mg$\^$2+/, Ca$\^$2+/and Cl$\^$-/ exhibited mostly a bimodal coarse mode size distribution, while ammonium and sulfate were mainly in the fine size range, with maximum at around 0.54$\mu\textrm{m}$. The average molar concentration ratio of ammonium to sulfate for fine particles was equal to 2.0${\pm}$0.9. Nitrate was evenly found in both the coarse and fine modes. Elements like Al, Fe, Cu, Mg, Na, Ti, Sr and Mn were dominant in coarse particles, with the maximum at around 5.25$\mu\textrm{m}$. S and Pb were mainly in the submicrometer size range. Other elements with a fine and coarse modes were V, Ni, Cu, Ba and Mo. The patterns of the size distributions of trace elements measured at the downtown in Jeju City were very similar to those at the coastal site in Hamduk. However, the amplitude of size fractional concentrations at Jeju City was narrower than that at Hamduk. While the mass median diameters for the chemical species originated from the natural origin such as marine and crust were relatively large, those for ammonium, sulfate, S and Pb were very small.

• Journal of the Korean Solar Energy Society
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• v.32 no.1
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• pp.8-14
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• 2012

Concerning about global warming due to emission of greenhouse effect gas like C02 and depletion of fossil fuels have been spreading. So the need for solar energy utilization is increased. It is essentially important to make efforts to reduce usage of fossil energy resources. In this study, we analyzed the correlation between climatic elements and the photovoltaic power generation. Cloud cover of the correlation coefficient was 0.93. The order of the correlation coefficient was average temperatures, hours of sunshine duration of sunshine and the humidity. To accurately analyze of the degree of correlation for the photovoltaic power generation, additional research about climatic elements that show a high correlation is needed.

• Journal of The Geomorphological Association of Korea
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• v.25 no.3
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• pp.19-42
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• 2018

In this study, we surveyed weathering progressing aspect by major elements variation and rock hardness by using XRF analysis, schmidt hammer, and thin section analysis. This observation suggested that the weathering process is likely to develop differently according to microstructural characteristics. R-value on the inside wall are lower than those on the outside. Also, the shadier the environment was, the closer it was to inshore areas, the R-value appeared to be lower. The movement of the elements such as Ca, Na and K shows that feldspar is hydrolyzed and can form salt crystallization like a gypsum or halite when they combine with the elements such as S or Cl. It proved a high CaO, $Na_2O$ and $K_2O$ content on flaking inside wall and rock meal. The exfoliation was mainly observed along the shady backwall and ceiling of tafoni. This helped in predicting the growth of tafoni as well as the direction of its progress.

• East Asian Journal of Business Economics (EAJBE)
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• v.8 no.4
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• pp.67-77
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• 2020

Purpose - This work tries to analyze the transformation of sectoral innovation pattern as time goes by to enhance the understanding on sectoral innovative activities, particularly considering the change of the nature of knowledge, and the trend of convergence. Research design, data, and methodology - This work tries to identify main factors, which determine the output of technological innovation through the econometric analysis, utilizing the result of Korean Innovation Survey and find a stylized fact on the change of the innovation pattern. Result - As a result of estimation, some major elements show different effects for two discrete years, 2002 and 2010; in chemical industry the open information source and neutral basic research become more important with the appropriation mechanism such as patents, and in machinery industry, the importance of internal information has been getting decreased with rising importance of customers. Conclusion - This work presents that some elements show different effects for two discrete years. Among three major elements, the source of information and appropriation mechanism shows different features for both industries. This means that we should explicit consider the changing nature of innovative environment, which leads to and heavily influence whether the innovative activity would be effective or not when we design innovation strategy and innovation policy.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4664-4670
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• 2023

Radiation is the main safety issue for almost all nuclear applications, which must be controlled to protect living organisms and the surrounding materials. In this context, radiation shielding materials have been investigated and used in nuclear technologies. The choice of materials depends on the radiation usage area, type, and energy. Polymer materials are preferred in radiation shielding applications due to their superior characteristics such as chemical inertness, resistivity, low weight, flexibility, strength, and low cost. In the presented work, ABS polymer material, which is possibly the most commonly used material in 3D printers, is mixed with Gd₂O₃ and Er₂O₃ nanoparticles. ABS filaments containing these rare-earth elements are then produced using a filament extruder. These produced filaments are used in a 3D printer to create shielding samples. Following the production of shielding samples, SEM, EDS, and gamma-ray shielding analyses (including experiments, WinXCOM, GEANT4, and FLUKA) are performed. The results show that 3D printing technology offers significant enhancements in creating homogeneous and well-structured materials that can be effectively used in gamma-ray shielding applications.

• Journal of Preventive Medicine and Public Health
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• v.14 no.1
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• pp.97-110
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• 1981

This study was conducted in order to investigate the status of harmful working environ ment on twelve rubber and ten chemical products manufacturing industries in Busan area over a period of five months from lune 1 to October 31, 1980. The summarized results were as follows: 1. The highest and lowest mean values of harmful environmental elements in workroom of rubber products manufacturing industries were noted in twisting (98.7dB) and coating department (77.3dB) to noise, molding ($6.43mg/m^3$) and forming ($1.33mg/m^3$) to dust, bonding (toluene 463.7ppm, xylene 457.8ppm and benzene 111.8ppm, respectively) and splicing (toluene 90.0ppm, xylene 83.3ppm and benzene 6.7ppm, respectively) to organic solvents, respectively. Also in chemical products manufacturing, they were noted in grinding (95.1dB) and shining department (76.8dB) to noise, packing ($4.30mg/m^3$) and staining ($3.20mg/m^3$) to dust, shining (393.3ppm and 375.0ppm, respectively) and varnishing(125.5ppm and 121.7ppm, respectively) to toluene and xylene, and scattering (51.8ppm) and mixing (23.9ppm) to benzene, respectively. 2. The mean values of harmful elements in workroom of rubber products manufacturing were 86.3dB to noise, $4.16mg/m^3$ to dust, 258.2ppm to toluene, 230.3ppm to xylene, and 5 4.0ppm to benzene, respectively. Also in chemical products manufacturing, they were 85.2dB to noise, $3.69mg/m^3$ to dust, 227.9ppm to toluene, 213.2ppm to xylene, and 36.3ppm to benzene, respectively. 3. Number of workers exposed to harmful working environment, over TLV, of a total 10,195 workers in rubber products manufacturing were 1,002(9.8%) to noise, 212 (2.1%) to dust, 1,581(15.5%) to toluene, 1,509(14,8%) to xylene, and 1,524(15.0%) to benzene, respectively. Number of workers exposed to harmful working environment, over TLV, of a 1,913 workers in chemical products manufacturing were 112(5.9%) to noise, 132(6.9%) to each organic solvent, respectively. 4. The values of noise and dust of rubber and chemical products manufacturing in 1980 were lower then those in 1977, but the value of organic solvent in 1980 was similar with that in 1977.

• Journal of the Mineralogical Society of Korea
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• v.24 no.2
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• pp.101-110
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• 2011

Charcoal burning in the process of manufacture and ordinary use often release many constituent chemical species. As a result of open burning, the chemical composition as well as the physical properties of original material changes through the modification of surface properties of charcoal. Surface modification could be more responsible toward the outside elements for surface adsorption, it becomes easy to adsorb more toxic elements through surface adsorption. In this study, four kinds of commercially available charcoal were studied against the chemical and thermal stability along with the heavy metals and organic hazardous substances. Thermo gravimetric analysis (TGA) and differential scanning calorimetry, from room temperature to $400^{\circ}C$, were performed to study the weight loss and the changes in the behavior of those substances. According to TGA analysis, about 10% of weight loss was happened before $200^{\circ}C$. It was found that related weight loss of this temperature region may responsible to the gas phase organic matter. Natural charcoal, K1 and C1 show 15% of loss during the reaction heated to $400^{\circ}C$, while the artificial charcoal K2, C2 show the weight loss of about 20% was found. This is consistent with the main organic matter and VOC analysis results shown. Chemical composition based on the x-ray diffraction analysis was carried out. X-ray diffraction analysis reveals the existence of chemical additive in the forms of $Ba(NO_3)_2$, $BaCO_3$, and $NaNO_3$.