• Korean Journal of Soil Science and Fertilizer
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• v.22 no.4
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• pp.271-279
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• 1989

Mean values representing the particle size distribution and some chemical properties for the cultivated soils were obtained from the analysis results of the typical profiles, which were described by the detailed soil maps throughout Korea. Analysis results of 5,215 soil samples (3,075 for paddy and 2,140 for upland) were available for the determination of mean values. The results are under. 1. Paddy topsoil contained 20.4% for clay, 5.8 for pH, 2.6% for organic matter, 10.4me/100g for exchangeable K, and 89ppm for available $P_2O_5$. Upland topsoil did 17.3% for clay, 5.5 for pH, 1.8% for organic matter, 9.lme/100g for CEC, 0.29me/100g for exchangeable K, and 103ppm for availabal $P_2O_5$. 2. Soil properies for paddy were markedly influenced by the reliefs. Topsoil contained 21.4% for clay, 6.0 for pH, 2.2% for organic matter, 10.8me/100g for CEC, 0.39me/100g for exchang-cable K and 57ppm for available $P_2O_5$ on the fluvio-marine plain, 15.3%, 5.7, 2.0%, 8.6me/100g, 0.17me/100g and 76ppm on the alluvial plain, 18.8%, 5.9, 2.7%, 10.4me/100g, 0.19me/100g and 80ppm on the valleys and fans, 25.0%, 5.7, 2.5%, 11.5me/100g, 0.26me/100g, 0.27me/100g and 141ppm on the moutain foot slopes, respectively. 3. Soil Properties for upland, also, were markedly influenced by the reliefs. Topsoil contained 5.5% for clay, 5.7 for pH, 1.1% for organic matter, 4.7me/100g for CEC, 0.17me/100g for exchangeable K and 50ppm for available $P_2O_5$ on the fluvio-marine plain, 10.3%, 5.5, 1.4%, 7.6me/100g, 0.26me/100g and 160ppm on the alluvial plain, 13.9%, 5.4, 1.8%, 9.3me/100g, 0.24me/100g and and 184ppm on the valleys and fans, 29.8%, 5.3, 2.1%, 11.2me/100g 0.40me/100g and 58ppm on the alluvial plain, 20.0%, 5.7, 2.7%, 11.4me/100g, 0.32me/100g and 116ppm on the mountain foot slopes, and 24.6%, 5.3, 1.8%, 10.2me/100g, 0.28me/100g and 51ppm on the rolling and Hill. 4. All chemical properties did not reach the ideal value for maximizing land capability. 5. Organic matter, exchangeable cations and available $P_2O_5$ were not normally distributed. Intervals of one and two standard deviations about mean of an approximately normal distribution were calculated.

• Membrane Journal
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• v.5 no.1
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• pp.26-34
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• 1995

In this study, polysulfone was carboxylated(CPSf), as a method of introducing carboxyl group to polymer main chain using direct lithiation reaction. Then, poly(1-alkyl-4-vinylpyridinium iodide-co-divinylbenzene) (MeVpI-DVB) containing pyridinium cation which has an anion selectivity as a fixed carrier was synthesized. And polymer membranes were prepared by mixing CPSf and MeVpI-DVB. Characteristics and permeation of membranes were investigated. As a result of synthesizing CPSf/MeVpI-DVB, blend was formed, not new copolymer. As the content of CPSf amount increasing, thermal stability of membranes was increasing. Ion exchange capacity was 1.0~1.8(meq/g dry mem.) and water content was 0.16~0.26(g $H_2{O}$)/g dry mem.) and fixed ion concentration was 6.4~7.3(meq/g $H_2{O}$) in synthetic membranes. The $Cl^-$ flux showed an increase due to the increase of CPSf content.

• Journal of Environmental Science International
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• v.10 no.4
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• pp.305-310
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• 2001

pH($H_2O$), pH(KCI), CEC(cation exchange capacity), O.M.(organic matter) and exchangeable cations(K, Na, Ca, Mg) of paddy soil, upland soil and forest soil in Kumi city were investigated for the purpose of knowing soil acidification and the correlation between soil acidification and leaching of inorganic salts. The mean pH($H_2O$) values of paddy soil were 5.23(surface soil) and 5.69(subsoil) and 4.74(subsoil). The were 6.37(surface soil) and 6.11(subsoil), and those of forest soil were 4.67(surface soil) and 4.74(subsoil). The mean pH(KCl) values of paddy soil were 4.59(surface soil) and 4.98(subsoil) were 5.48(surface soil) and 5.04(subsoil), and those of forest soil were 3.82(surface soil) and 3.89(subsoil). The acidification of forest soil was more rapid than that of paddy soil and upland soil/ The total mean amounts of exchangeable cations(K, Na, Ca, Mg) in paddy soils were 6.14me/100g(surface soil) and 5.64me/100g(subsoil), and those in upland soils were 6.86me/100g(surface soil) and 6.65me/100g(subsoil), and those in forest soils were 4.06me/100g(surface soil) and 3.34me/100g(subsoil). The contents of inorganic salts in forest soil were much less than those of paddy soil and upland soil. The correlation coefficients(r) between pH($H_2O$) values and the total amounts of exchangeable cations in soils were $0.6635^{**}$(surface soil) and $0.6946^{**}$(subsoil), and those between pH(KCl) values and exchangeable cations in soils were 0.6629(surface soil) and $0.5675^{**}$(subsoil). The correlation between soil acidification and leaching of inorganic salts in soil was positively significant at 1% level.

• BMB Reports
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• v.37 no.6
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• pp.657-662
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• 2004

Oligoribonucleotides containing 8-oxo-7,8-dihydroguanosine (8-oxoG) and 8-oxo-7,8-dihydro-2'-O-methylguanosine (8-oxoG-Me) were synthesized. The base pairing properties of 8-oxoG and 8-oxoG-Me in oligoribonucleotide in cDNA synthesis by reverse transcriptases were studied. dCMP was preferentially incorporated into the site opposite 8-oxoG or 8-oxoG-Me than into other dNMPs. TMP and dCMP were inserted preferentially into sites opposite 8-oxoG or 8-oxoG by reverse transcriptases. HIV-RT did not incorporate TMP, but RAV2-RT incorporated 50% more TMP than dCMP into the site opposite 8-oxoG. In the site opposite 8-oxoG-Me TMP was substantially incorporated by HIV-RT or RAV2-RT. Thermodynamic analysis of the DNA. RNA heteroduplex containing 8-oxoG revealed that 8-oxoG and 8-oxoG-Me formed base pairs with cytidine and thymidine with similar stability. The thermodynamic parameter (${\Delta}G^{\circ}$) demonstrated that the formation of duplexes between 8-oxoG or 8-oxoG-Me and cytidine or thymidine is more thermodynamically favorable than with adenosine and guanosine. However, differences in the melting temperature and ${\Delta}G^{\circ}$'s of 8-oxoG/dC and 8-oxoG/T were much smaller than between G/dC and G/T. CD spectra showed that DNA . RNA containing 8-oxoG or 8-oxoG-Me duplexes showed similarities between the A-type RNA and B-type DNA conformations.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.2
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• pp.173-178
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• 1984

Correlation study was conducted to establish the optimum test level of soil improvement for good growth of corn from the relationships between the corn yield and soil chemical properties in 16 farmers' demonstration fields. Significant positive correlations between the corn yield and soil chemical properties ; pH, available phosphorus, exchangeable potassium, calcium, magnesium, cation exchange capacity. available silica, and base saturation percentage were showed but organic matter and nitrogen content were not. The proper nutrient contents in soil for expecting corn yield, 1.000kg/10a could be estimated as pH 5.6, available phosphorus 327ppm, exchangeable potassium 0.39me/100g, exchangeable calcium 5.5me/100g, exchangeable magnesium 1.3me/100g, cation exchange capacity 11.5me/100g, available silica 116ppm, base saturation percentage 58 from the relationships between the corn yield and soil chemical properties. Exchangeable aluminium were negatively correlated with not only corn yield but also pH, available phosphorus, exchangeable potassium and exchangeable calcium.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.2
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• pp.67-71
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• 1993

This study was carried out to develop the soil conditioner and/or the absorbent of high CEC with the natural zeolite poeder whose price was very low. The $SiO_2/Al_2O_3$ ratio & CEC of the natural zeolite were 6.78 and 67.5me/100g respectively. The CEC of the post-reaction product which was treated with 3N-NaOH and $Na_2O/Al_2O_3$ ratio. 9.5 for 8hours was about 200me/100g, which was the highest value than any other treatments. The dominant clay minerals were clinoptilolite, mordenite and smectite in natural zeolite, while phillipsite in the post-reaction product.

• Bulletin of the Korean Chemical Society
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• v.17 no.9
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• pp.802-807
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• 1996

Second-order rate constants have been measured spectrophotometrically for the reactions of aryl benzoates (X-C6H4CO2C6H4-Y) with EtO-, Z-C6H4O- and Z-C6H4C(Me)=NO- in absolute ethanol at 25.0 ℃. All the reactions have been performed in the presence of excess 18-crown-6 ether in order to eliminate the catalytic effect shown by alkali metal ion. A good Hammett correlation has been obtained with a large ρ- value (-1.96) when σ- (Z) constant was used for the reaction of p-nitrophenyl benzoate (PNPB) with Z-C6H4O-. Surprisingly, the one for the reaction of PNPB with Z-C6H4C(Me)=NO- gives a small but definitely positive ρ- value (＋0.09). However, for reactions of C6H5CO2C6H4-Y with EtO-, correlation of log k with σ- (Y) constant gives very poor Hammett correlation. A significantly improved linearity has been obtained when σ0 (Y) constant was used, indicating that the leaving group departure is little advanced at the TS of the RDS. For reactions of X-C6H4CO2C6H4-4-NO2 with EtO-, C6H5O- and C6H5C(Me)=NO-, correlations of log k with σ (X) constants for all the three nucleophile systems give good linearity with large positive ρ values, e.g. 2.95, 2.81 and 3.06 for EtO-, C6H5O- and C6H5C(Me)=NO-, respectively. The large ρ values clearly suggest that the present reaction proceeds via a stepwise mechanism in which the formation of the addition intermediate is the RDS.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.2
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• pp.210-219
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• 2017

This study aimed to establish an optimal extraction process and high-performance liquid chromatography (HPLC)-photodiode array (PDA) analytical method for determination of marker compounds, dihydrokaempferol (DHK) and 3-O-methylquercetin (3-MeQ), as a part of materials standardization for the development of health functional foods from stems of Opuntia ficus-indica var. saboten (OFS). The quantitative determination method of marker compounds was optimized by HPLC analysis, and the correlation coefficient for the calibration curve showed very good linearity. The HPLC-PDA method was applied successfully to quantification of marker compounds in OFS after validation of the method in terms of linearity, accuracy, and precision. Ethanolic extracts from stems of O. ficus-indica var. saboten (OFSEs) were evaluated by reflux extraction at 70 and $80^{\circ}C$ with 50, 70, and 80% ethanol for 3, 4, 5, and 6 h. Among OFSEs, OFS70E at $80^{\circ}C$ showed the highest contents of DHK and 3-MeQ of $26.42{\pm}0.65$ and $3.88{\pm}0.29mg/OFS100g$, respectively. Furthermore, OFSEs were determined for their antioxidant activities by measuring 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and lipid peroxidation (LPO) inhibitory activities in rat liver homogenate. OFS70E at $70^{\circ}C$ showed the most potent antioxidant activities with $IC_{50}$ values of $1.19{\pm}0.11$ and $0.89{\pm}0.09mg/mL$ in the DPPH radical scavenging and LPO inhibitory assays, respectively. To identify active components of OFS, various chromatographic separation of OFS70E led to isolation of 11 flavonoids: dihydrokaempferol, dihydroquercetin, 3-O-methylquercetin, quercetin, isorhamnetin 3-O-glucoside, isorhamnetin 3-O-galactoside, narcissin, kaempferol 7-O-glucoside, quercetin 3-O-galactoside, isorhamnetin, and kaempferol 3-O-rutinoside. The results suggest that standardization of DHK in OFSEs using HPLC-PDA analysis would be an acceptable method for the development of health functional foods.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.889-893
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• 2011

The energetics and transition state (TS) structures of the reactions of six substrates, $R_1R_2P$(=O or S)Cl-type where $R_1=R_2$=Me and/or MeO, with ammonia in acetonitrile are theoretically investigated at the level of CPCM-MP2/6-31+G(d) and CPCM-MP2/6-311+G(3df,2p). The degrees of distortion of TS from the ideal trigonal bipyramidal pentacoordinate, ${\Delta}{{\delta}}_{{\neq}b}$ for a backside and ${\Delta}{{\delta}}_{{\neq}f}$ for a frontside attack, are calculated. The results of calculation suggest that the feasibility of a frontside attack for P=S is greater than that for P=O system when the two ligands, $R_1$ and $R_2$, becomes larger. The experimental and calculated results of anilinolyses of $R_1R_2P$(=O or S)Cl-type show the consistent tendencies.

• Journal of Sericultural and Entomological Science
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• v.23 no.2
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• pp.50-54
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• 1982

This investigation was conducted to know the present conditions of the the chemical components in the soils and chemical fertilizer rates applied in the Yuyu village located Sanne myun, Buan gun, Jeonbug province. Total silkworm rearing farms in this village were 54 and 47 of them were chosen at random. Average fertilizer rate applied in this village was 40.8-13.7-13.9kg/10a as N-P$_2$O$\_$5/-K$_2$O. Farmers seemed to stress too much to nitrogen fertilizer. Available P$_2$O$\_$5/ in soils was below 7ppm (by Bray No. 1 method). However, 47% of the farms applied phosphate fertilizer less than 11kg/10a. The average of exchangeable K in soils was 0.68me/100g. Nine of the farms applied potassium fertilizer more than 20kg/10a and 7 farms of them had the soils contained above 0.4me/100g as the potassium content. The average soil pH was 5.3. All of the soils were below than pH 6.5. Exchangeable Ca and Mg were 3.62 and 0.83me/100g, respectively. The average lime requirement was 269kg/10a. The average organic matter content was 2.55% and for 72% of the total farms, organic matter content was below than 3%.