• Journal of the Mineralogical Society of Korea
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• v.17 no.3
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• pp.209-220
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• 2004

Adsorption behavior of Cu onto Hwangto, from Pankok-ri, Kosung-gun, suspension was studied using Cu batch adsorftion experiment and computer program MINTEQA2 and FITEQL 3.2. The sorption of copper was investigated as a function of pH, copper concentration and $NaNO_3$ background concentration (0.01 and 0.1 M). The concentration of copper was analyzed using ICP-AES. The sorption of copper onto Hwangto suspension increased with increasing pH and copper concentration. The adsorption percentage of copper drastically increased from pH 5.5 to 6.5, and reached nearly 100% at pH 7.5. Because the amount of copper solution and the ionic strength of background electrolyte may not affect the sorption of copper onto Hwangto, the copper ion may be combined at the surface of Hwangto as an inner-sphere complex. Using the MINTEQA2 program, the speciation of copper was calculated as a function of pH and copper concentration. The concentration of $Cu^{2+}$ decreased and that of $Cu(OH)_2$ increased with increasing pH. The uptake of copper in the Hwangto suspension was simulated by FITEQL3.2 program using two sites-three pKas model, which is composed of silicate reaction site and Fe oxide reaction site. The copper absorption reaction constants were calculated in the case of 2～6 mL of copper solution. The Fe oxide reaction site rapidly adsorbs copper ion between pH 4.5～6.5. Silicate reaction site adsorbs little copper ion at low copper concentration but much at high copper concentration. The removal amount of copper by precipitation was negligible in comparison with that of adsorption. The Fe oxide reaction site may has higher adsorption affinity of copper ion than silicate reaction site.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.6
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• pp.538-544
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• 1985

This study was carried cut to evaluate the water quality of spring waters in Pusan area(see Fig. 1). In this experiment, twenty-five water samples were collected from 5 stations from December 1983 to August 1984. Range and mean values of constituents of the samples are as follows: pH $5.80{\sim}7.25$, 6.60; water temperature $6.0{\sim}23.0^{\circ}C,\;12.9^{\circ}C$; total residue $33.0{\sim}325mg/l$, 121.2mg/l; alkalinity $4.75{\sim}51.6mg/l$, 24.1mg/l; hardness $9.47{\sim}85.0mg/l$, 30.3mg/l; electrical conductivity $0.495{\sim}2.750{\times}^2{mu}{\mho}/cm,\;1.239{\times}10^2{\mu}{\mho}/cm$;turbidity $0.54{\sim}7.80$NTU, 2.04NTU; $KMnO_4$ consumed $0.51{\sim}8.47mg/l$, 1.96mg/l; chloride ion $4.91{\sim}36.0mg/l$, 12.55mg/l; fluoride ion ND-0.30ppm, 0.08ppm; nitrate-nitrogen ND-8.94mg/l, 1.94m:g/l; nitrite-nirogen ND-0.10mg/l, 0.03mg/l; ammonia-nitrogen ND-0.16mg/l, 0.03mg/l: phosphate-phosphorus ND-0.09mg/l, 0.03mg/l; silicate-silicious $0.42{\sim}22.7ng/l$, 7.96mg/l; copper ND-10.5ppb, 2.46ppb; lead ND-22.7ppb, 3.54ppb; zinc ND-103ppb, 21.33ppb; iron $20.3{\sim}2,800ppb$, 801.72ppb, respectively. Arsenic, cyan, cadmium, manganese, mercury, chrome and phenol were not detected. Total residue, electrical conductivity, turbidity and chloride ion of station 1 (Milrakdong) were higher than others as 178.1mg/l, $2.127{\times}10^2{\mu}{\mho}/cm$, 3.16NTU and 16.32mg/l. The concentration of silicious had a great influence on precipitation. The concentration of fluoride ion of spring waters was lower as 0.08ppm than the criterion for drinking water as 1ppm, while iron was exceed 2.7 times as 801.72ppb.

• Korean Journal of Environmental Agriculture
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• v.33 no.3
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• pp.169-177
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• 2014

BACKGROUND: The ferronickel and rapid cooling slags used in present study are industrial wastes derived from a steel factory in Korea. These slags are used as almost road construction materials after magnetic separation. However, the use of slag to remove phosphorus from wastewater is still a relatively less explored. The objective of this work was to evaluate the feasibility of ferronickel slag (FNS) and rapid cooling slag (RCS) as sorbents for phosphorus removal in wastewater. METHODS AND RESULTS: Adsorption experiments were conducted to determine the adsorption characteristics of the FNS and RCS for the phosphorus. Adsorption behaviour of the phosphorus by the FNS and RCS was evaluated using both the Freundlich and Langmuir adsorption isotherm equations. FNS and RCS were divided into two sizes as effective sizes. Effective sizes of FNS and RCS were 0.5 and 2.5 mm, respectively. The adsorption capacities (K) of the phosphorus by the FNS and RCS were in the order of RCS 0.5 (0.5105) > RCS 2.5 (0.3572) ${\gg}$ FNS 2.5 (0.0545) ${\fallingdotseq}$ FNS 0.5 (0.0400) based on Freundlich adsorption isotherm. The maximum adsorption capacities (a; mg/kg) of the phosphorus determined by the Langmuir isotherms were in the order of RCS 0.5 (3,582 mg/kg) > RCS 2.5 (2,983 mg/kg) > FNS 0.5 (320 mg/kg) ${\fallingdotseq}$ FNS 2.5 (187 mg/kg). RCS 0.5 represented the best sorbent for the adsorption of phosphorus. In the experiment, the Langmuir model showed better fit with our data than the Freundlich model. CONCLUSION: This study indicate that the use of RCS in constructed wetlands or filter beds is a promising solution for phosphorus removal via adsorption and precipitation mechanisms.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.1
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• pp.38-48
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• 2002

This study examines the relationships between atmospheric influences and grain yields including yield components as well as growth stages. Data used in this study were collected from the long-term field experiment at Suwon for the period between 1974 and 2000. Mean grain yield of barley cultivar, Olbori, for the recent 14 years(1987∼2000) with warm winters was higher by 0.42 ton per hectare than that for 27 years(1974∼2000) at Suwon as a result of the higher numbers of spikes per unit land area and grains per spike. However, the 1000-grain weight decreased by about 0.6 gram. Mean first day of regrowth for the recent 14 years was earlier by five days than that for 27 years. Also, beginning date of regrowth was positively correlated with that of heading and ripening. Mean period of ripening for the years of 1987 through 2000 was similar to that for 27 years, but mean period of overwintering was shorter by nine days than that for 27 years. On the other hand, mean periods of seedling and tillering were longer by three days than those for 27 years. Meteorological elements at various growth stages affecting grain yield of winter barley were air temperature (positive correlation) and sunshine hour (negative correlation) of overwintering stage, precipitation (negative correlation) of tillering stage, and potential evapotranpiration (positive correlation) of tillering stage. The 1000-grain weight was not significantly correlated with the meteorological elements. Culm length was negatively influenced by high temperature and dry weather situations during the ripening period, but spike length was positively influenced. Overall, it was found that grain yield of barley, cultivar Olbori, was iufluenced by meteorological elements of overwintering, tillering, and ripening stages.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.2
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• pp.52-60
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• 2009

This study was conducted to quantify the soil respiratory $CO_2$ emission (SR) in an apple orchard and to determine its relationship with key environmental factors such as air temperature, soil temperature and soil moisture content. Experiment was made over the period from 23 April 2007 to 31 March 2008 in 'Fuji' apple orchard of National Institute of Horticultural and Herbal Science in Suwon, Gyeonggi-do, Korea. The SR was measured by using the automatic opening/closing chamber system based on a closed method. Diurnal variations in SR showed an increase around 0700 hours with increasing soil temperature, its peak between 1400 and 1500 hours, and then a gradual decrease thereafter. Daily variations in SR depended largely on soil and air temperatures over the year, ranging from 0.8 to 13.7 g $CO_2$ $m^{-2}d^{-1}$. During the rainy spell in summer (July$\sim$Autumn) with higher temperature and more precipitation, the SR was lower than that in the spring (May$\sim$June) with moderate temperature. The SR showed a significant exponential relationship with soil temperature ($r^2=0.800$) and air temperature ($r^2=0.805$), but not with soil moisture content ($r^2=0.160$). The $Q_{10}$ values of SR with annual soil temperature and air temperature were 2.0 and 1.9, respectively. The annually integrated SR was 19.6 ton $CO_2$ $ha^{-1}$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.421-430
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• 2015

Rural Development Administration has recently developed mid-late maturing rice cultivars with high quality. This study was conducted to select suitable mid-late maturing rice cultivar in major cultivation areas of Gangwon Province among domestic breeding cultivars for 2 years from 2013 to 2014. The average air temperature during the experiment in 2013 and 2014 was higher $0.6{\sim}1.1^{\circ}C$ in Chuncheon, $1.0{\sim}1.3^{\circ}C$ in Gangreung, and $0.1{\sim}0.7^{\circ}C$ in Cheolwon than normal year. Precipitation in ripening period was higher 52.5 mm in 2013, but lower 176.4 mm in 2014 than normal year in Chuncheon, lower 103.1 mm in 2013 and higher 42.9 mm in 2014 in Gangreung, lower 225.9~322.7 mm in Cheolwon. Duration of sunshine in ripening period was higher 142 hours in Chuncheon, 108 hours in Gangreung, and 94 hours in Cheolwon than normal year in 2013, higher 20~21 hours in Chuncheon and Gangreung, and 82 hours in Cheolwon than normal year in 2014. Milled rice yield of 'Samgwangbyeo' and 'Daebobyeo' was 594 kg per 10a, and 578 kg for 'Jinsumibyeo' in Chuncheon in plain area. For Gangreung in east coastal area, the yield of 'Daebobyeo' was 555 kg per 10a, 'Hopumbyeo' was 554 kg, and 'Chilbobyeo' was 546 kg. For Cheolwon in mid-mountainous area, the yield was 504 kg per 10a for 'Daebobyeo' and 489 kg for 'Haiamibyeo'. But there was no difference in milled rice yield among cultivars tested in the study at each area. Head rice ratio of 'Haiamibyeo', 'Jinsumibyeo', and 'Mipumbyeo' in Chuncheon was 94.2~95.6% higher than the other cultivars. In Gangreung head rice ratio of 'Hopumbyeo', 'Haiamibyeo', and 'Samgwangbyeo' were 85.2~88.3% but there was no difference among cultivars except 'Gopumbyeo' and broken rice ratio of 'Haiamibyeo', 'Samgwangbyeo', and 'Mipumbyeo' were low as 7.5~8.5% and palatability of 'Mipumbyeo' was higher than the other cultivars. Head rice ratio of 'Daebobyeo' was the highest as 89.2% and there was no difference in broken and chalky rice ratio and palatability among cultivars in Cheolwon. Considering rice yield and quality in major cultivation areas of Gangwon Province, suitable mid-late maturing rice cultivars were 'Samgwangbyeo', 'Haiamibyeo', and 'Jinsumibyeo' in Chuncheon, 'Daebobyeo' and 'Chilbobyeo' in Gangreung, and 'Daebobyeo' and 'Haiamibyeo' in Cheolwon. The results obtained in the study imply that the selected cultivars with high yield and quality and suitability to Chuncheon, Gangreung, and Cheolwon, respectively could be recommended to rice cultivating farmers in the regions with high priority.

• Economic and Environmental Geology
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• v.43 no.4
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• pp.305-314
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• 2010

The stabilization process using limestone ($CaCO_3$) and steel making slag as the immobilization amendments was investigated for As contaminated farmland soils around Chonam abandoned mine, Korea. Batch and continuous column experiments were performed to quantify As-immobilization efficiency in soil and the analyses using XRD and SEM/EDS for secondary minerals precipitated in soil were also conducted to understand the mechanism of Asimmobilization by the amendments. For the batch experiment, with 3% of limestone and steel making slag, leaching concentration of As from the contaminated soil decreased by 62% and 52% respectively, compared to that without the amendment. When the mixed amendment (2% of limestone and 1% of steel making slag) was used, As concentration in the effluent solution decreased by 72%, showing that the mixed of limestone and steel making slag has a great capability to immobilize As in the soil. For the continuous column experiments without the amendment, As concentration from the effluent of the column ranged from 50 to $80\;{\mu}g/L$. However, with 2% limestone and 1% steel making slag, more than 80% diminution of As leaching concentration occurred within 1 year and maintained mostly below $10\;{\mu}g/L$. Results from XRD and SEM/EDS analysis for the secondary minerals created from the reaction of the amendments with $As^{+3}$ (arsenite) investigated that portlandite ($Ca(OH)_2$), calcium-arsenite (Ca-As-O) and calcite ($CaCO_3$) were main secondary minerals and the distinct As peaks in the EDS spectra of the secondary minerals can be observed. These findings suggest that the co-precipitation might be the major mechanisms to immobilize As in the soil medium with limestone and steel making slag.

• Restorative Dentistry and Endodontics
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• v.32 no.2
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• pp.151-161
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• 2007

Dental caries is the most common disease in the oral cavity However, the mechanism and treatment of dental caries is not completely understood since many complex factors are involved. Especially the effect of pH on remineralization of early stage of dental caries is still controversial In this study, dental caries in dentin was induced by using lactic acidulated buffering solutions and the loss or inorganic substance was measured. Also decalcified specimens were remineralized by three groups of solution with different pH (group of pH 4.3, 5.0, and 5.5). Then, the amount and the area of inorganic substance precipitation was quantitatively analyzed with microradiograph. Also a qualitative comparison of the normal phase the demineralized phase, and the remineralized phase of hydroxyapatite crystal was made under SEM. The results were as follows, 1. In microradiograghic analysis, as the pH increased, the amount of remineralization in decalcified dentin tended to increase significantly As the pH decreaced, deeper decalcification, however, occurred along with remineralization. The group of pH 5.5 had a tendency to be remineralized without demineralization (p<0.05). 2. In SEM view, the remineralization in dentine caries occurred from the hydroxyapatite crystal surface surrounding the mesh of organic matrix, and eventually filled up the demineralized area. 3. 5 days after remineralization, hydroxyapatite crystal grew bigger with deposition of inorganic substance in pH 4.3 and 5.0 group, and the crystal in the remineralized area appeared to return to normal. After 10 days, the crystals in group of pH 4.3 and 5.0, which grew bigger after 5 days of remineralization, turned back to their normal size, but in group of pH 5.5, some crystals were found to double their size. In according to the results of this experiment, the decalcifying and remineralizing process of dentine is neither simple nor independent, but a dynamic process in which decalcification and remineralization occur simultaneously. The remineralization process occurred from the hydroxyapatite crystal surface.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.153-159
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• 2011

BACKGROUND: This experiment was conducted to investigate the distribution and burden characteristics of heavy metal in the rainwater sampled at Taean area, in the middle part of Korea, from April 2002 to October 2003. METHODS AND RESULTS: The relationship between concentration of heavy metal and other chemical properties in the rainwaters was also evaluated. Chemical properties in the rainwater were various differences with raining periods and years. It appeared that a weighted average pH values of rainwater was ranged from 5.0 to 5.1. Heavy metal concentrations in the rainwater were ranked as Pb > Zn > Cu > Ni > As > Cr > Cd. As compared with heavy metal concentrations of rainwater in 2002, Cu, Pb, and Zn were higher than other elements in 2003. There were positive correlation between major ionic components, such as ${NH_4}^+$, $Ca^{2+}$, $Mg^{2+}$, $K^+$, $Na^+$, ${SO_4}^{2-}$ and ${NO_3}^-$, and As, Cd, Zn, Cr, and Ni concentrations in rainwater. For heavy metal distribution of rainwater, the order of average enrichment factor was Cd > Pb > As > Cu > Zn > Ni > Cr, and these were relatively higher than the natural components such as Fe, Mg and Ca. The monthly enrichment factor were relatively high, from August to October at Taean. The monthly amount of heavy metal precipitation was high in the rainy season from July to August because of great influence of rainfall. CONCLUSION(s): The results of this study suggest that the heavy metals(Cd, Pb, As, Cu, and Zn) of rainwater is strongly influenced by anthropogenic sources rather than natural sources.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.4
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• pp.371-382
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• 2011

The aim of the present study was to investigate the relationship between climates, growth characteristic and yield of silage corn at Hanwoo Experiment Station, National Institute of Animal Science, Daegwallyeong in Gangwon Province located at altitude of 760 m, from 2009 to 2010. The mean minimum temperature was $12.29^{\circ}C$ from seeding to harvest in 2009, $14.30^{\circ}C$ in 2010, the mean maximum temperature was $21.66^{\circ}C$, $23.48^{\circ}C$, respectively. The mean temperature was $16.85^{\circ}C$ in 2009 and $18.55^{\circ}C$ in 2010, respectively. Duration of sunshine was 711.3 hours in 2009 and 663.8 hours in 2010, and precipitation was 893.8 mm in 2009 and 752.1 mm in 2010, respectively. In 2009, for all Kwangpyeongok, Gangdaok, Cheonganok, Cheongsaok, Pyeonganok, the early growth was good with 1.2, while in 2010 the growth for Pyeonganok was good with 1.3 comparing to others, which showed worse growth than in the previous year with 2.4~3.0. There was significant difference in the ear height between 2009 and 2010, showing mean value of 85.8 cm and 105 cm for all the species in 2009 and in 2010, respectively (p<0.001). In 2010, stem diameter for all the species were larger, and there was significant difference in mean value of the diameter between 2009 and 2010 (p<0.001). There was significant difference in the plant height and ear height between 2009 and 2010, showing 200 cm and 258 cm in 2009 and 2010, respectively (p<0.001). There was significant difference in the average days to silk, showing 103.8 days in 2009, 90 days in 2010, respectively (p<0.001). There was no lodging or disease-insect damage in all hybrid silage corn in both 2009 and 2010. The mean ear rates were 23.4% in 2009, but almost doubled, 52.1%, in 2010. There was significant difference in fresh yield between the two years, showing 54,611 kg/ha in 2009 and 78,733 kg/ha in 2010, respectively (p<0.001). Dry matter yields were higher in 2010 than in 2009. TDN yields of Gangdaok and Cheonganok were higher in 2009, whereas that of Cheongsaok and Pyeonganok were higher in 2010. Crude protein contents were higher in 2010 than in 2009 for all the species.