간행물
한국환경과학회지 KCI 등재 Journal of Environmental Science International
- 발행기관 한국환경과학회
- 자료유형 학술지
- 간기 월간
- ISSN 1225-4517 (Print)2287-3503 (Online)
- 수록기간 1992 ~ 2023
- 주제분류 자연과학 > 자연과학일반 자연과학 분류의 다른 간행물
- 십진분류KDC 539DDC 628
권호리스트/논문검색
제5권 제5호 (1996년 10월) 14건
1.
1996.10
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The toxic substances (endotoxins) from the bacterial cell walls were extracted by using incubator, centrifuge, UV-Vis spectrophotometer, and their fatty acid compositions were analyze by Gas Chromatography. The lethal toxicities and pyrogenic activities of toxic substances were tested and the results were compared each other.
The results of fatty acid analyses showed that the major fatty acid of the toxic substance was tetradecanoic acid for Vibrio vulnificus, dodecanoic acid for Escherichia coli and decanoic acid for Salmonella typhimurium. These three fatty acids were the main fatty acids for three toxic substances (more than 70%). The unique points in the fatty acid compositions were that tetradecanoic acid was composed as important one (37.15%) for V. vulnificus and that the amount of hexadecanoic acid was very small (below 2%) for three toxic substances. The lethal toxicity in ICR mice of toxic substance from V. vulnificus (LD_50 was 52.5 ㎎/㎏) was similar to that of E. coli (56.5 ㎎/㎏), but weaker than that of S. typhimurium (37.5 ㎎/㎏). Toxic substance from V. vulnificus was more pyrogenic in rabbit than that from E. coli, but less than that from S. typhimurium.
2.
1996.10
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A method for the simultaneous analysis of 31 residual organic chloride pesticides was studied using gas chromatography. Prepared analytical samples were injected to gas chromatography (HP 5890 Series II plus) on the Ultra-2 column with ECD. The packing materials for column were changed as the following reagents ; florisil and alumina N. The residual solution was loaded to column and was eluted with elution solvents ; ether : benzene (2 : 8) solution, hexane : benzene (1:1) solution, dichloromethane, acetone, and methanol.
The analytical results showed that 6 kinds of organic chlorides were not detected when florisil (first condition) was used as the column packing material. The nondetected 6 kinds of organic chlorides in the first analytical condition were detected and the recoveries of thrin-pesticides were increased, in particular, captan and captafol, but the recoveries of benzene hexachloride compounds were decreased when dichloromethane and methanol were added as elution solvents (packing material was florisil as in the first condition). The recoveries of dichlorfluanid, chlorofenvinfos, folpet, and dicofol were increased and that of aldrin was increased, but those of captan and captafol were not good when alumina N was used as the packing material.
To detect simultaneously thrin-pesticides, captan, and captafol, florisil and alumina N were used as the packing materials. The elution result showed that captan and captafol were not detected. This was because the column was activated insufficiently. The analytical method was the best (31 kinds of organic chlorides in the residual pesticides were detected sharply and showed high sensitivity) when the column (packing materials were florisil and alumina N, together) was fully activated and the impurities were removed using various elution solvents.
3.
1996.10
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The pure compound chloromethanes; methyl chloride, methylene chloride, chloroform and carbon tetrachloride were used as a model of chlorocarbon system with Cl/H ratio to investigate thermal stability and hydrodechlorination process of carbon tetrachloride under excess hydrogen atmosphere.
The parent thermal stability on basis of temperature required for 99% destruction at 1 second reaction time was evaluated as 875℃ for CH3Cl, 780℃ for CH2Cl2, 675℃ for CHCl3, and 635℃ for CCl4. Chloroform was thermally less stable than CCl4, at fairly low temperatures (<570℃). The decomposition of CCl4, became more sensitive to increasing temperature, and CCl4 was degraded easier than CHCl3 at above 570℃.
The number and quantity of chlorinated products decreases with increasing temperature for the product distribution of CCl4 decomposition reaction system. Formation of non-chlorinated hydrocarbons such as CH4, C2H4 and C2H6 increased as the temperature rise and particularly small amount of methyl chloride was observed above 850℃ in CCl4/H2 reaction system. The less chlorinated products are more stable, with methyl chloride the most stable chlorocarbon in this reaction system.
4.
1996.10
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This study is involved to develop new catalysts to decompose plastics, detergents and surfactants containing synthetic peptide bonds. As the first year research, the catalytic hydrolysis of amide bond in copper complex was accomplished. The hydrolysis reaction in aqueous solution was monitored by UV/VIS spectroscopy. As the pH of the solution is increased and the temperature is raised, the reaction rate increases. The reaction rate is observed as the first order kinetic behavior for the copper complex. The metal catalyzed hydrolysis mechanism is proposed via metal-hydroxide in the pH region of 5.5 to 6.3. The results of characterization of the catalytic reaction mechanism can be applied to develop new catalysts for peptide bond degradation in further research.
5.
1996.10
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Trifluralin (2,6-dinitro-N, N-dipropy1-4- (trifluormethyl) benzenamine) was applied preemergent to soybean in plots drained or nondrained, in Louisiana. Plots 14.6 ㏊ were arranged to give 1683 g/㏊ of trifluralin. The half life of trifluralin in the top 15㎝ of soil was 42.6 days and 46.0 days in nondrained plot and drained plot, respectively. The concentrations of trifluralin in surface runoff water and subsurface runoff water were 0.62 ng/mL-0.02 ng/mL and 0.06 ng/mL-0.02 ng/mL, respectively. The concentration of trifluralin in runoff water was smaller than 2 ng/mL for trifluralin of U.S. Environmental Protection Agency advisory. Total loss of trifluralin in runoff water was 0.021% of applied amount at drained plots during three month after application. Trifluralin was moved hardly in the water. Subsurface drainage reduced trifluralin losses because concentration of trifluralin in the subsurface runoff water in drained fields was low.
6.
1996.10
서비스 종료(열람 제한)
A dual-porosity filmed agglomerate model for the porous cathode of the molten carbonate fuel has been investigated to predict the cell performance. A phenomenological treatment of molecular, kinetic and electrode parameters has been given. The major physical and chemical phenomena being modeled include mass transfer, ohmic losses and reaction kinetics at the electrodeelectrolyte interface. The model predicts steady-state cell performance given the above conditions that characterize the state of the electrode. Quasi-linearization and finite difference techniques are used to solve the coupled nonlinear differential equations. Also, the effective surface area of electrode pore was obtained by mercury porosimeter. The results of the investigation are presented in the form of plots of overpotential vs. current density with varied the electrode material, gas composition and mechanism. The predicted polarization curves are compared with the empirical data from 1 ㎠ cell. A fair correspondence is observed.
7.
1996.10
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The bacteriophage from the fresh oyster, Crassostrea Vrginiea which is specific to the marine bacterium was isolated and characterized. Among the four different vibrio species and the five different serotypes of. Vibrio parahaemolyticus host strains tested, only two strains of Vibrio parahaemolyticus possessing K17, K52 antigens were highly sensitive to the phage. The size of the isolated plaque was 0.4㎜ and the electron microscopic head size of the isolated phage was about 67 nm long and 83 nm wide. PFU/㎖ was 1.25×10^11. The phage was sensitive to chloroform but resistant to acetone or methanol. The assay of the iseoted phage nucleic acid was deoxyribonucleic acid. The restriction enzyme pattern showed 14 fragments from Hind Ⅲ and 4 fragments from Eco R I. Two different antigenic groups showed similar restriction enzyme patterns.
8.
1996.10
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The effects of nutritional sources on growth of Pseudomonas sp. P2 were investigated in medium containing biphenyl as a carbon source. To determine characterization of Pseudomonas sp. P2, the incubation time was determined to 100 h of the log phase in the growth curve. The optimal compositions for the growth of Pseudomonas sp. P2 degrading polychlorinated biphenyls (PCBs) were 1000 ㎎/L NH4NO3, 1000 ㎎/L KH2PO4, 100 ㎎/L MgSO4·7H2O, 30 ㎎/L CaCl2·2H2O, 200 ㎎/L NaCl, and 10 ㎎/L FeSO4·7H2O. Pseudomonas sp. P2 showed the degradability of 59.3 %, 57.6%, 51.4%, and 48.7% at 500 ㎎/L, 1000 ㎎/L, 1500 ㎎/L, and 2000 ㎎/L of the PCBs within insulating oil after 100 h incubation under the optimum conditions, respectively.
9.
1996.10
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Intraseasonal variability of the tropical convection over the Indian/western Pacific is studied using the Geostationary Meteorological Satellite high cloud amount. This study is directed to find the tropical-extratropical interaction in the frequency range of intraseasonal and interannual variabilities of the summer monsoon occured over the domain of 90E-171W and 49S-50N. Especially, in order to investigate the intraseasonal interaction of East Asia summer monsoon associated with the tropical convections in the high cloud amounts, the spatial and time structure of the intraseasonal oscillation for the movement and the evolution of the large-scale convections are studied.
To describe the spatial and the time evolution, the extended empirical orthogonal function analysis is applied. The first mode may be considered to a normal structure, indicating that the strong convection band over 90E-120E is extended to eastward, but this mode was detected as a variable mode near Korea and Japan. The second, third and fourth modes were amplified with the intraseasonal variability during summer monsoon. It is found that the dominant intraseasonal mode of the tropical convection consists of the spatial changes over a broad period range centered around 40∼50days.
10.
1996.10
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Rice plants cv. Koshihikari, were subjected to the biologically effective ultraviolet-B (UV-B_BE) radiation {daily dose : 0.0 (control) and 11.5 (enhanced UV-B) kJ m^-2} to investigate the effect of enhanced UV-B radiation on lipid peroxidation and to determine whether carotenoids and polyamines are involved in protection mechanism against enhanced UV-B radiation. Enhanced UV-B radiation significantly depressed plant dry weight. Malondialdehyde (MDA) content in rice leaves was increased by about 30% after 6 days of UV-B irradiation. Total carotenoid contents tended to slightly decrease with the UV-B irradiation, even though there was no significance. In rice leaves, 3 major polyamines, putrescine, spermidine and spermine are observed. All of the polyamine contents were increased with UV-B irradiation. The results suggest that enhanced UV-B radiation caused oxidative stress on lipids and that polyamines may serve as a biochemical protectant against increased UV-B radiation in rice plants.
11.
1996.10
서비스 종료(열람 제한)
Various light intensity and light quality were treated to oat seedlings to investigate the effect of light on the chlorophyll accumulation and the formation of chlorophyll-protein complexes. The increase of total chlorophyll accumulation and Chl (chlorophyll) a/b ratio was promoted under H (high intensity) white light during oat chloroplast development when compared to L (low intensity) white light. Also H white right was more effective in the formation of chlorophyll-protein complexes associated with PSI, CCI and CCII than L white light. The seedlings grown in various light quality caused little changes in total chlorophyll and Chl a/b ratio when compared to those grown in L white light. The assembly of LHCII trimer was more affected by L white light treatment in the formation of-chlorophyll-protein complexes than red light treatment. The effect of blue light on the relative composition of chlorophyll-protein complexes was similar to that of L white light. Particualrly, blue light was more effective in the synthesis of LHCII monomer than the other hot quality at the early stage of greening. When compared to red light, blue light was more effective in the formation of LHCII monomer. These results suggest that light intensity is more effective in the increase of chlorophyll accumulation and Chl a/b ratio than light quality, and light quality may be an important factor for the regulation of the organization in the chlorophyll-protein complexes during greening.
12.
1996.10
서비스 종료(열람 제한)
Meteorological and flux data measured from semiarid watersheds (Lucky Hills and Kendall) during the summer rainy and winter periods were used to study the sensitivity of the those variables used in the estimation of evapotranspiration rates. Relative sensitivity was examined to compare the importance of four meteorological and flux variables (net radiation, wind speed, air temperature, and relative humidity) on Penman potential evapotranspiration (PET) estimation. The study results show that variations in Penman PET rates during the summer rainy period at both watersheds appears to be controlled by air temperature adn net radiation. During the winter period at both watersheds, variations in Penman PET rates appears to be controlled by relative humidity and air temperature.
13.
1996.10
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The analyzed results of observed precipitation and its pH in Kwangju for 262 days from Jan. 1, 1991 to Dec. 31, 1995 are as follows.
The annual mean pH was 5.7, and the monthly mean pH values of January-May and November were less than 5.6 in Kwangju. The ratio of acid rain for these periods was about 48.1 %, almost half that of the total observed days. In March, the pH was 5.4 and the ratio of acid precipitation was 69%, an especially serious situation. In the spring, the pH value was 5.5 thus weak acidic. The pH of precipitation tended to decrease with greater precipitation. The relation between persistent time and pH of precipitation is variable, but if the persistent time is long, the pH is constant and low. It is fortunate that there is an increasing trend of pH in interannual variation, but it is thought important that the amplitude of variation of pH in 1995 was high and the pH value was 4.1 in October and November. Because heavy and persistent precipitation effects the accumulation of acidity, more concern about acid rain is needed.
NOTE
14.
1996.10
서비스 종료(열람 제한)
The electrochemical carbon dioxide reduction to produce acetaldehyde, methanol and ethanol is investigated by using perovskite type electrode (La0.9Sr0.1CuO3). The experiments were performed under 100 mA/㎠ and -2 to -2.5 V vs. Ag/AgCl. The highest faradaic efficiencies for methanol, ethanol, acetaldehyde were 11.6, 15.3, and 6.2%, respectively. The experimental data demonstrated that the capability of the perovskite type oxide for the electrode of electrochemical carbon dioxide reduction to produce alcohols was superior to other metal electrode.
