• Journal of Soil and Groundwater Environment
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• v.21 no.6
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• pp.169-178
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• 2016

The Standards, Measurement and Testing Programme (SM&T-formerly BCR) extraction procedure was applied to fractionate Cr, Cu, Ni, Pb and Zn in 23 top soil samples into: (i) exchangeable phase; (ii) reducible phase; (iii) oxidisable(sulfides and organics bound) phase; and (iv) residual phase. Fractions of Cr and Ni were in the order of residual > oxidisable > reducible > exchangeable phase. The oxidisable phase was identified as dominant for Cu and Pb. Zn had the highest ratio of exchangeable phase in comparision to the other metals. The bioavailability and mobility were assessed to be the greatest for Zn, followed by a decreasing order of Pb, Cu, Ni and Cr. All metal average concentrations in topsoil samples was higher in industrial sites than in agricultural sites. Our results revealed higher concentrations in topsoil samples (0~15 cm) than in sub soils (15~30 cm, 30~60 cm) for most metals at six sites (No. 5, 6, 17, 19, 20, 23). The fractions of exchangeable, reducible ad oxidisable phases showed relatively high correlation with soil pH, Fe/Mn oxide concentrations and organic matter contents, respectively.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.334-340
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• 2005

The chemical forms of Cd, Cu, Pb, and Zn were analysed by sequential extraction technique to evaluate the effects of drying and heating of dredged sediments from Lake Chungcho. The most abundant fraction of Cd, Cu, and Zn in the wet and untreated sediment was organic/sulfidic fraction that is state in reducing environment such as the bottom condition of Lake Chungcho, while Pb dominated in residual fraction. This means that the source of Cd, Cu, and Zn in the Chungcho lake sediment is related to the organic degradation and Pb to the erosion from surrounding rocks. With drying and oxidation by dredging, heating treatment, and disposal of the lake sediment, the chemical forms of studied metals changed greatly from organic/sulfidic fraction to adsorbed and reducible fractions which are more labile in oxygenated environment. Organic/sulfidic fraction of Cd, Cu and Pb in the wet sediment was transformed with drying and heating treatments to the labile ones like adsorbed and reducible fraction, but Zn to carbonate and reducible fraction. Heating of the sediment at $320^{\circ}C$ greatly increased the labile fraction of Cd and Cu, while that at $105^{\circ}C$ for Pb and Zn. It is believed that the increase in labile forms of heavy metals in the sediments by drying and heating is caused by the contact with oxygen during drying and heating and by the increase of pH of the pore water at the expense of organic/sulfidic fraction. It is concluded that the drying and oxidation currently used in the treatment of dredged sediment can increase labile forms of heavy metals in the sediment, and the potential of the metal availability from the sediment.

• Kyungpook Mathematical Journal
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• v.52 no.2
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• pp.149-153
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• 2012

We show that the above lemma and its well-known refinement are valid, in a general setting, in non-commutative rings. Some interesting consequences are also observed.

• Bulletin of the Korean Mathematical Society
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• v.39 no.2
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• pp.347-357
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• 2002

In this paper, we study the concepts of isocompactness and cl-isocompactness. We generalize a pure space defined by Arhangelskii and get some results on initially K-compact spaces. We also consider open problems related to isocompactness and cl-isocompactness.

• Korean Journal of Ecology and Environment
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• v.41 no.2
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• pp.166-173
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• 2008

Chemical forms and release potential of heavy metals were studied in the lime treated sediment of lake Chungcho. Chemical forms of heavy metals were analyzed using a sequential extraction method, and release potential of heavy metals was evaluated by the ratio of the content of labile forms to total metal one. Dominant form of Cd, Cu, Pb, and Zn in the untreated sediments was organic/sulfidic form that is stable in the reducing environment such as the bottom of Lake Chungcho. With liming of the sediment, the chemical forms of studied metals were greatly changed from organic/sulfidic form to adsorbed and reducible form, especially Cd and Cu to adsorbed and reducible form, but Pb and Zn to reducible form. It is believed that increase of unstable form of heavy metals in the sediments by liming was caused by the increase of pH of the pore water at the expense of organic/sulfidic form. Thus, we concluded that the liming approach currently used in the treatment of dredged sediments might cause the increase of labile form which is easily dissolved, and may increase the release of metals from the sediment into overlying water.

• Bulletin of the Korean Mathematical Society
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• v.37 no.3
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• pp.543-550
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• 2000

We prove that every generalized Landsberg manifold of scalar curvature R is a Riemannian manifold of constant curvature, provided that $R\neq\ 0$.

• Journal of the Chungcheong Mathematical Society
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• v.12 no.1
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• pp.23-31
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• 1999

The purpose of the present paper is devoted to a study of some properties on spaces with a quartic metric from the standpoint of Finsler geometry.

• Journal of Environmental Science International
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• v.26 no.7
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• pp.847-858
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• 2017

For 26 soil series distributed more than 1% among 63 soil series in Jeju Island, natural uncultivated soil samples were collected. For these soils, the chemical speciation of eight heavy metals (Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn) was examined. Further, the Plant Bioavailability (PB) and Mobility Factor (MF) of these heavy metals were evaluated using Tessier's 5-step sequential extraction method (exchangeable, carbonate, reducible (bound to Fe/Mn oxides), oxidizable (bound to organic matter), and residual fraction). The main form present was residual fraction for Cd and Zn; residual and oxidizable fractions for Cr, Cu, Ni, and Pb; reducible fraction for Mn; and carbonate fraction for V. The average plant availability and average mobility factor were found to be V (57.37%) > Zn (12.49%) > Cd (11.76%) > Cu (11.19%) > Pb (9.37%) > Cr (9.09%) > Mn (3.13%) > Ni (2.63%), and Mn (61.04%) > V (59.94%) > Zn (31.54%) > Cd (17.65%) > Cr (15.66%) > Ni (13.89%) > Pb (13.80%) > Cu (13.53%), respectively.

• Journal of the korean society of oceanography
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• v.36 no.1
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• pp.9-18
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• 2001

Chemical speciation of five heavy metals (Cr, Cu, Ni, Pb, Zn) has been analyzed from 37 surface and 2 core sediments of Kyeonggi Bay, using the modified sequential extraction method based on Tessier et at. (1979). The results show that heavy metals in the Kyeonggi Bay surface sediments are associated dominantly with the crystal lattice fraction. But in the polluted sediments of the Incheon North Harbor, the importance of the labile fractions increased while that of the lattice fraction decreased. In particular, the adsorbed and the easily reducible fractions showed a noticeable increase. In the core samples emerged a speciation pattern which differed significantly from that of the surface sediments. A sharp increase in the percentage of the reducible and organic/sulfide fractions and a decrease in the lattice fraction were observed. Throughout the vertical column, however, the metal contents in the lattice fraction showed stability while those of the labile fractions showed an upward increase. The strong association of heavy metals with the organic/sulfide fraction could be attributed in part to the sulfate reduction prevailing in the polluted harbor sediments.

• Applied Chemistry for Engineering
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• v.4 no.4
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• pp.823-829
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• 1993

The basic medium oil modified alkyd resin was synthesized from linseed oil fatty acid(LOFA), phthalic anhydride(PAA), trimellitic anhydride(TMA ), and trimthylol propane(TMP) by condensation polymerization at $230^{\circ}C$. TMPTA modified water-reducible alkyd resins were synthesized with TMPTA graft copolymerization onto the basic resin at $180^{\circ}C$. Acid value of the resin was controlled by the addition of TMA and N,N-Dimethylethanol amino(DMEA) was used as an neutralizing agent to prepare water-reducible alkyd. To evaluate the optimum formulation for anionic alkyd resin, water proofness and water reducibility were estimated from the acid value or TMA contents. The effect of TMPTA on the graft copoymerization of the resin was studied by measuring molecular weight, glass transition temperature(Tg), viscosity, and gel contents. The suitable balance of water proofness and water reducibility of the resin was obtained at range of 5.3~7.0wt.% of TMA contents or 40~50 of acid value of basic resin. The molecular weight, viscosity, and gel contents of water-reducible alkyd resin were increased according to the TMPTA graft copolymerization, but Tg was decreased.