• Korean Journal of Soil Science and Fertilizer
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• v.37 no.6
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• pp.365-370
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• 2004

To invesligate the characteristics of silica sorption on soils silica sorption experiments were conducted with 9 soils at 4 pH levels (5, 6, 7, and 8). Silica sorption increased in great extent with increase of pH. At the same pH level silica sorption increased linearly with increase of equilibrium $SiO_2$ concentration. Silica sorption characteristics was C-type. The C-type slope, i.e., the slope of linear regression of silica sorption isotherm, increased exponentially with increase of pH in all soils. Log(C-type slope) increased linearly with increase of pH in all soils. The slopes of linear regression were similar in most soils from 0.29 to 0.34 except Sachon and Jonggog soil. None of the soil properties showed any correlation with the slope of linear regression of Log(C-type slope) to pH. Only $Fe_o$ (oxalate extractable Fe oxides) was significantly correlated with the Log(C-type slope) at pH 7 in simple correlation analysis, and was shown to be the principal contributor as determined by standardized multiple linear regression.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.603-612
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• 2012

In order to select potato clones for making cold chip, this study analyzed the glucose content, acrylamide content, and the correlation between the two properties after harvest, $4^{\circ}C$ and $8^{\circ}C$ low-temperature storage, and $20^{\circ}C$ heating treatment of 47 breeding clones and control cultivars 'Atlantic', 'Sumi', and 'Gui Valley'. In all of the control cultivars and 47 clones, glucose content was below 0.25% and acrylamide content was below 1000 ppb just after harvest, but after $4^{\circ}C$ low-temperature storage both the glucose content and acrylamide content increased rapidly and only 4 clones H7, H13, H16, and H40 showed a level below 500 ppb. In $8^{\circ}C$ low-temperature storage as well both contents increased, but the increase was relatively smaller than that in $4^{\circ}C$ low-temperature storage. In addition, $20^{\circ}C$ heating treatment decreased both contents. In the results of analyzing the correlation between glucose content and acrylamide content at low-temperature storage, a positive correlation was observed. In conclusion, clones H7, H13, H16, and H40 showing low glucose content even at low-temperature treatment were found to contain less acrylamide and therefore they were selected as potato clones suitable for making cold chip.

• Resources Recycling
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• v.18 no.6
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• pp.18-23
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• 2009

An investigation on the synthesis of aluminum citrate, one of the aluminum organic compounds, has been performed using aluminum chloride solutions as a starting material. For the synthesis of aluminum citrate, citric acid was added to aluminum solutions with the mole ratio of citric acid to aluminum to be 2.5 and aluminum citrate synthesized was also characterized in terms of chemical analysis, X-ray diffraction, particle size measurement and SEM analysis. As a result, it was found that the ratio of ethanol/Al solution more than 4.0 was required for the synthesis of aluminum citrate from aluminum solutions. Furthermore, the pH should be controlled to be more than 7.0 in order to obtain the recovery of aluminum citrate higher than 97%. From the chemical analysis of aluminum citrate synthesized in this work, the content of $NH_4$, Al and C was found to be 17.0, 4.01 and 25.7%, respectively. Accordingly, the aluminum citrate synthesized from aluminum solutions was confirmed to be $(NH_4)_5Al(C_6H_4O_7)_2{\cdot}2H_2O$.

• The Korean Journal of Food And Nutrition
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• v.14 no.3
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• pp.263-268
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• 2001

NaIO$_4$-산화 전분당을 Bacillus licheniformis의 $\alpha$-아밀라아제의 반응시켜서 시프염기 형성으로 당단백질로 변형시켜서 안정성을 확인하였다. 10$0^{\circ}C$에서의 열안정성은 10분 뒤에, pH 9.7에서 변형한 효소 비변형 효소의 순으로 높았다. 그러나 변형 및 안정성에 $\alpha$-cyclodextrin($\alpha$-CD)을 사용한 결과 큰 차이는 나지 않았다. pH 8.0에서 $\alpha$-CD 존재하에 변형한 효소는 pH 8~11dml 알칼리쪽에서 가장 높은 안정성을 나타냈으나, pH 5~7사이에는 다른 효소보다 낮았다. pH 9.7에서 변형하지 않은 효소는 pH 5부터 pH 13까지 서서히 증가하였고 pH 9.7에서 $\alpha$-CD존재 하의 효소는 pH 5부터 7까지 증가하다가 그 후 pH13까지 서서히 감소하였다. $\alpha$-CD존재하의 비변형 효소는 pH 7과 10에서 피크를나타낸 다음 pH12이후에는 급격히 낮아졌다. 변형한 효소는 HPLC 의 유출시간이 빨라wu서 변형하지 않은 효소보다 분자량이 큰 것으로 나타났다. 분자량 크기는 비변형 효소

• Korean Journal of Weed Science
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• v.16 no.4
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• pp.292-300
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• 1996

This experiment was conducted to investigate the factor of phytotoxicity for herbicides(bensulfuron methyl, pyrazosulfuron-ethyl, dimepiperate, molinate) on flood direct-seeded rice. The phytotoxicity of herbicides was evaluated under controlled environment condition. Bensulfuron methyl and pyrazosulfuron-ethyl reduced more rice growth, especially root growth on low temperature(20/$11^{\circ}C$) than high temperature(30/$22^{\circ}C$) cultivations. The phytotoxicity of bensulfuron methyl and pyrazosulfuron-ethyl were increased relatively by non-nutrient and nutrient solution. cultivation, respectively. The rice applied bensulfuron methyl and pyrazosulfuron-ethyl with pH 3.5, 5.5, 7.5 and 9.5 solution became low growth rate on low pH of pH 3.5 and 5.5 solution cultivation. Bensulfuron methyl application with pH 5.5 and pH 7.5 solution, and pyrazosulfuronethyl application with pH 7.5 and 9.5 solution reduced rice growth inhibition. The root growth of rice seeded in 6cm depth of water solution applied herbicides was suppressed by bensulftuon methyl and pyrazosulfuron-ethyl, the growth of shoot was suppressed heavily by dimepiperate and molinate, in particular dimepiperate suppressed about the growth of 90%. The phytotoxicity of pyrazosulfuron-ethyl became high on light clay soil of non-fertilizer condition and sand loam soil of fertilizer condition, bensulfuron methyl became high on sand loam soil.

• Microbiology and Biotechnology Letters
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• v.37 no.4
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• pp.350-354
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• 2009

A Gram-negative, alginate lyase-producing bacterium was isolated from the Haeundae Coast, Korea. The isolated strain N7151-6 produced alginate lyase. The optimal temperature and pH for growth were found to be $30^{\circ}C$ and pH 8.0, respectively. This strain can be grown at the NaCl concentration of 0-7% (w/v). Analysis of 16S rDNA sequence and physiological profiling indicated that the strain N7151-6 belonged to Pseudomonas sp. The enzyme alginate lyase produced by Pseudomonas sp. N7151-6 was partially purified by ultrafiltration (MWCO= 30 kDa). The optimum pH and temperature for the activity of the purified enzyme were found to be 7.0 and $30^{\circ}C$, respectively. The enzyme was stable at the pH range of 5.0-9.0 and temperature range of $23-30^{\circ}C$. The total activity of alginate lyase produced was reached about 110 unit/L.

• Journal of environmental and Sanitary engineering
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• v.16 no.4
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• pp.62-68
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• 2001

The advantages of hydrogen peroxide dissolution method were no discharge of noxious matter when dissolution of iron wire which used as the center supporter, reactions occur in room temperature and easy to recover dissolved iron. This study was aimed at gathering the basic data of iron wire dissolution- recovery process and proposes the reaction condition of iron wire dissolution- recovery process rind the factors influencing those reactions. The results were as follows : 1 . Hydrogen peroxide dissolution method used hydrochloric acid as the catalyst. 1. In the dissolution of iron wire(1.668 g), the condition of reaction was E1702(30 ml), HCI(20 ml) and $H_2O$(200 ml) ; time of the reaction was 18 min. P.W.(Piece weight) was 7.75 mg, and C.R. was $2.34{\;}{\Omega}$ 2. In the dissolution of iron wire(1.529 g), the condition of reaction was H7O2(30 ml), HCI(20 ml) and $H_2O$(200 ml), time of the reaction was 21 min., P.W.(Piece weight) was 7.73 mg, and C.R. was $2.35{\;}{\Omega}$. Hydrogen peroxide dissolution method used sulfuric acid as the catalyst. 1. In the dissolution of iron wire(0.834 g), the condition of reaction was $H_2O$(65 ml), $H_2SO_4$(5 ml) and 1702(5 ml) ; time of the reaction was 5 min.30 sec, P.W.(Piece weight) was 7.74 mg, and C.R. was $2.33{\;}{\Omega}$ 2. In the dissolution of iron wire(1.112 g), the condition of reaction was $H_2O$(65 ml), $H_2SO_4$(5 ml) and $H_2O_2$(5 ml) ; time of the reaction was 4 min.30 sec, P.W.(Piece weight) was 7.75 mg, and C.R. was $2.33{\;}{\Omega}$. Hydrogen peroxide dissolution method used hydrochloric acid and sulfuric acid as the catalyst confirmed a clean technology, because there were not occurred a pollutant discharged in the existing method.

• Microbiology and Biotechnology Letters
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• v.9 no.4
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• pp.213-218
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• 1981

The molecular weight of the purified $\beta$-galactosidase of Penicillium sp. was estimated to be 130000 by both Sephadex G-200 gel filtration and SDS-polyacrylamide del electrophoresis. The SDS-electrophoresis gave two protein bands corresponding to the two molecular weights of 130000 and 70000. These results indicated that the enzyme consisted of two probably identical subunits which had a molecular weight of 70000. The optimum pH of the enzyme activity was 4.7 and maximum activity appeared at 5$0^{\circ}C$. The stable pH range for the enzyme was from 4.5 to 7.0. The purified $\beta$-galactosidase had no metal ion requirement for its activity or stability. The enzyme activity was inhibited by C $u^{++}$(1mM)and galactose (100mM). The hydrolysis of lactose in 5% lactose solution, pasteurized milk and 10% skim milk solution were 69.5%, 88.7% and 72.6% after 4 hr incubation at 5$0^{\circ}C$, when 10 units of $\beta$-glucosidase were used per $m\ell$ of the substrate solutions.s.

• Bulletin of the Korean Chemical Society
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• v.21 no.7
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• pp.734-740
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• 2000

Density functional theory calculations are presented for the geometrical isomers of the cyanopolyacetylenes H(C≡C)n,,C≡N (n = I-3). The structures, hartmonic frequencies and dipole moments are computed, employing the 6-311G** basis set. The ener gies of barrier to isomerization (exchange of carbon and nitrogen atoms) are also computed in order to estimate the stability of the isomers in interstellar space.

• 한국해양학회지
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• v.1
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• pp.37-48
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• 1971

Observations of water temperature, salinity, pH and transparency of the Ko-ri sea area were made between May 1969 and April 1970. A seasonal thermocline was well defined in August, strongly isolating the warm serface water(19-22$^{\circ}C$) from the cold bottom water (14-17.5$^{\circ}C$) introducing from the open sea. In February the coldest isothermal water (11$^{\circ}C$) occurred. In the warm months(May- September), the salinity patterns show great variations with the coastal run-off During the cold months(December-April) the highest isohaline water (35 ) occurred. Annual ranges of surface and bottom pH values were 7.8-8.4(averaging 8.27) and 7.9-8.4(averaging 8.26), respectively. The transparency was greatest (6.0-7.0m) during winter and spring months and least (1.2-2.5m) during summer months.