• Journal of Korean Society for Atmospheric Environment
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• v.16 no.1
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• pp.49-60
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• 2000

The concentration of atmospheric mercury(Hg0 and relevent environmental parameters that include both meteorological and criteria pollutant data were dtermined at hourly intervals during two field campaigns covering the periods of September 1997 and May/June 1998. The mean concentrations of Hg for the two study periods were computed as 3.94 and 3.43ngm-3, respectively. Through a separation of these data into both daytime and nighttime periods, we further analyzed diurnal variation patterns for Hg between two different seasons. Using our Hg data sets, we were able to recognize two contrasting diurnal variation patterns of Hg between two diffeerent seasons that can be characterized as: (1) the occurrences of peak Hg concentration during daytime(fall0 and (2) slight reductions in daytime Hg concentration relative to nighttiime Hg data(summer). To study the systematic differences in diurnal patterns between two different seasons, we analyzed Hg data in terms of different statistical approaches such as correlation(and linear regression0 and factor analysis. Results of these analyses consistently indicated that different mechanisms were responsible for controlling the daytime distribution patterns of Hg. The variation of boundary layer conditions betwen day/night periods may have been important in introducing the relative reduction in daytime Hg levels during summer. However, when the relationship between Hg and concurrently determined O3 is concerned, these differences are unlikely to be an effective sink mechanism within the ranges of ozone concentrations determined concurrently during this study, regardless of season. To further provide the general account for short-term variations in Hg distribution data, we should be able to describe the various factors underlying its sink mechanism.

• Journal of Life Science
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• v.13 no.5
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• pp.618-625
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• 2003

Investigations were carried out to optimize the culture conditions for the production of xylanase by Paenibacillus sp. DG-22, a moderately thermophilic bacterium isolated from timber yard soil. Xylanase production showed a cell growth associated profile. Xylanase activity was found only in the culture supernatant, while $\beta-xylosidase$ activity was mainly associated with the cells. The formation of xylanase activity was induced by xylan and repressed by glucose and xylose. The production profile of xylanase was examined with various commercial xylan and maximum yield was achieved with 0.1∼ 0.5% birchwood xylan. Among various nitrogen sources tested, yeast extract was optimal for the production of xylanase. The xylanase activity was inhibited by $Co^{2+},\; Cu^{2+},\; Fe^{3+},\; Hg^{2+}\;$ and$\;Mn^{2+}$ ions while $Ca^{2+},\; Mg^{2+},\; Ni^{2+},\; Zn^{2+}$ions and DTT stimulated xylanase activity Mercury (II) ion at 5 mM concentration abolished all the xylanase activity. The predominant products of xylan-hydrolysate were xylobiose, xylotriose, and higher xylooligo-saccharides, indicating that the enzyme was an endoxylanase.

• Journal of the Korean Chemical Society
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• v.31 no.5
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• pp.444-451
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• 1987

The dependence of polarographic parameters on the pressure for the reduction of copper(II), cadmium(II), and zinc(II) complex ions with ethylenediamine, propylenediamine, and diethylenetriamine has been studied. In this study the dropping mercury electrode, the mercury pool electrode, and helix type of platinum wire were used as the working, the reference, and the auxilary electrode, respectively. With increasing the pressure from 1 atmosphere to 1,500 atmospheres, the reduction half-wave potentials of metal complex ions are shifted to the negative values and the diffusion currents become considerably larger, in keeping with the theory on the change of the physical properties of the electrolytic solution such as the density, the viscosity, the dielectric constant, and the electrical conductance, etc. The slope values of the logarithmic plot are increased with increasing the pressure, which indicates the more irreversible reduction. The temperature coefficients of diffusion current observed over the range of the temperature from 25$^{\circ}$C to 35$^{\circ}$C are about two percentage with increasing the pressure, therefore the polarographic reduction under the high pressure is controlled by diffusion. The linear relationships between diffusion current and concentration of metal complex ions are established over all pressure range.

• YAKHAK HOEJI
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• v.30 no.6
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• pp.281-287
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• 1986

Atmospheric mercury was collected by gold amalgamation method and analyzed by cold flameless atomic absorption spectrometry. The distribution of atmospheric mercury was investigated at seven location (rural I, II, industrial I, II, University and the center of urban) The amount of atmospheric mercury collected at the rural area I (Mt. Seolack) ranged from 0.7 to 1.8ng/$m^3$, and mean value was 1.2ng/$m^3$ (n=4), at the rural area II (Buyeo) ranged from 0.8 to 5.1 ng/$m^3$, and mean value was 2.0ng/$m^3$ (n=8), at the area of the center of urban (Jong-ro 3 Ga, Seoul) ranged from 22.7 to 43.1ng/$m^3$, and mean value was 35.1ng/$m^3$ (n=12), at tae residential area I (Galak Dong, Seoul) ranged from 2.2 to 5.1ng/$m^3$, and mean value was 3. 5 ng/$m^3$ (n=6) at the Chung-Ang University (Heukseok Dong, Seoul) ranged from 2.2 to 176.2 ng/$m^3$, mean value was 36.8 ng/$m^3$ and median value was 16.0 ng/$m^3$ (n=188), at the residential area II (Goowal Dong, Inchon) ranged from 6.4 to 20.7 ng/$m^3$, and mean value was 13.1 ng/$m^3$ (n=10), and at the industrial area (Songhyun Dong, Inchon) ranged from 13.9 to 88.3 ng/$m^3$, and mean value was 38.9 ng/$m^3$ (n=12). The behavior of atmospheric mercury concentration at Chung-Ang University showed high in day time and summer, but low in night-time and winter.

• Korean Journal of Organic Agriculture
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• v.14 no.4
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• pp.433-443
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• 2006

With treatment of Kitosan, Wood vinegear and EM(effective microoganism) which farmers call it as substance in fertilizing, conditioning and disease control substances, authors in vestigated on microorganisms change in soil and ealy growth characteristics of tomato. The results were summarized as follows: Among foliar application of kitosan, wood vinegear and EM(effective microoganism) treatments diluted by chitosan 500 times solution level was effective considering growth of tomato as compared other dilutions and control plot. Change of microorganism number in the soil for cultivation of tomato was increased with microorganism treatment plot as compared with control plot. Specially chitosan 500 times solution level showes the most significant effect.

• Journal of Environmental Health Sciences
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• v.35 no.4
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• pp.287-294
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• 2009

This study analysed the mercury concentration in the hair of 62 students (male : 21, female : 41) of D university in Najusi, Jeon-Nam area. Also, questionnaire, which developed by NIES, were completed by the students. According to the questionnaire, most of the students had a higher intake of meat than that of fish. Also, among the students, there were many smokes and many had dental treatment with amalgam. Based on the gender, female showed 1.024 ${\mu}g/g$ and male showed 0.882 ${\mu}g/g$ of the mercury concentration. This means that female students had higher level of mercury in their hair, but it was not a significant statistic difference. Comparing by the intake frequency of meat, processed food stuffs, protein foods, it shows the more they at the higher mercury concentration was observed. According to the intake frequency of fish, when the number of times they intake increased, the mercury concentration was higher. Under one time was 0.857 ${\mu}g/g$ and twice or more times were 1.152 ${\mu}g/g$, which showed a significant statistical difference (p<0.05). Depending on the Life style, the mercury concentration in the hair was high with workout, outdoor activities, and direct smoking. The mercury concentration in the hair showed no difference for whether they received amalgam treatment but the personal dietary habit and the Living condition affects strongly on the mercury concentration level.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.6
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• pp.458-467
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• 2016

Salt is the most important substance in physiological activities of the human body concerning transport of the ingested nutrients into the blood. Thus, the most ideal salt must not contain any harmful ingredients such as cadmium, mercury, lead, and arsenic. However, it is legal to include trace amounts of the hazardous ingredients in salt owing to a technical limitation, because salt is generally obtained from seawater. This paper reported an experimental result about a new method of manufacturing high-quality table salts without hazardous ingredients by using "$15^{\circ}C$ low-temperature vacuum drying technology," applied to the sequential extraction phenomenon of seawater with increasing the concentration. The world's best table salt can be produced if the present results are applied and extended to the traditional solar salt industry.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.1
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• pp.128-138
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• 2015

Carbonation is one of the most critical deterioration phenomena to concrete structures exposed to high $CO_2$ concentration, sheltered from rain. Lots of researches have been performed on evaluation of carbonation depth and changes in hydrate compositions, however carbonation modeling is limitedly carried out due to complicated carbonic reaction and diffusion coefficient. This study presents a simplified carbonation model considering diffusion coefficient, solubility of $Ca(OH)_2$, porosity reduction, and carbonic reaction rate for low concentration. For verification, accelerated carbonation test with varying temperature and MIP (Mercury Intrusion Porosimetry) test are carried out, and carbonation depths are compared with those from the previous and the proposed model. Field data with low $CO_2$ concentration is compared with those from the proposed model. The proposed model shows very reasonable results like carbonation depth and consuming $Ca(OH)_2$ through reduced diffusion coefficient and porosity compared with the previous model.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.3
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• pp.90-96
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• 2018

In this study, the mechanical and micro-structural change of cement pastes incorporating Stainless-Steel Slag Argon Oxygen Decarburization Slag (STS-A) containing ${\gamma}-C_2S$ as a carbon capture materials were investigated with carbonation curing condition. ${\gamma}-C_2S$ is non-hydraulic, therefore does not react with water. But ${\gamma}-C_2S$ has a reactivity under carbonation curing condition with water. The reaction products fill up the pore in pastes. The microstructure of STS-A blended cement pastes could be densified by this reaction. The pore structure of cement pastes incorporating STS-A was measured using mercury intrusion porosimetry (MIP) after carbonation curing ($CO_2$ concentration is about 5%). Also the fractal characteristics were investigated for the effect of carbonation curing on the micro-structural change of paste specimens. From the results, the compressive strength of carbonated specimens incorporating STS-A increased and pore-structure of carbonated paste is more complicated.

• Environmental Analysis Health and Toxicology
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• v.21 no.3 s.54
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• pp.229-238
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• 2006

Although, mercury (Hg) is not a naturally abundant element in the environment, residues frequently occur in many environmental compartments because of widespread contamination from industrial and agricultural practices. This research evaluated Hg-B concentrations of general population who was not occupationally exposed. And also evaluates the association between life factor and health effect with Hg-B concentration of general adult through interrelationship estimation and index about kidney function and oxidative damage that appeared by questionnaire survey and medical examination. Average concentration of Hg-B was 3.19 $\mu$g/L (ND$\sim$8.64 $\mu$g/L), and persons who exceed mercury exposure level (5 $\mu$g/L) presented in WHO (1990) appeared by 16 (7.0%). High-risk group (smoking and meat main intake group) had significantly higher Hg-B concentration than low-risk group (non-smoking and vegetable diet main intake group) (p < 0.05, low-risk group: 3.30 $\mu$g/L (ND$\sim$8.64 $\mu$g/L), high-risk group: 4.27 $\mu$g/L (ND$\sim$7.84 $\mu$g/L).