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
제6권 제1호 (1997년 2월) 11건
1.
1997.02
서비스 종료(열람 제한)
Varing the flow velocity of solution and particle diameter, the mass transfer coefficient of the local electrode on current feeder has been measured in an empty flow reactor, an inert fluidized bed electrode reactor, and an active fluidized bed electrode reactor. It had its maximium value when the bed porosity was 0.6 to 0.65 and decreased with increasing the height of local electrode. The mass transfer coefficient was found to be high especially when bigger particle was fluidized. Electrochemical deposition of copper dissolved in the synthesized wastewater has been performed in the active fluidized bed electrode reactor. The deduction rate was higher than 90% and the residual concentration of copper decreased to less than 5ppm.
2.
1997.02
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We investigated and analysed the actual conditions and characteristics of railroad noise levels for 17 sites in the vicinity of the Seoul-Pusan Line. The results are summarized. as follows : 1) Railroad noise level ranged to 64∼74 L_eq dB(A) at day time and ranged to 60∼72 L_eq dB(A) at night time. 2) Increased night noise level depend on the increase of trains passing at night time. 3) The major factor of increased noise level in the vicinity of stations are using loudspeakers and stream whistle on trains. 4) Decreased effect of noise according to distance is able to be described quantitatively using regression equations of multiplicative model. L_eq=78.59 X^-0.056 n=25, r=-0.994, s.e.=1.007 P_av =105.68X^-0073, n =25, r =-0.997, s.e. = 1.007 Also increased and decreased effect of noise according to floor in apartment is able to be described quantitatively using regression equations of multiplicative model. L_eq = 64.238 X^0.0567, n = 39, r = 0.787, s. e. = 1.004 P_av. = 79.963 X^0.0254 n = 39, r = 0.689, s. e. = 1.056 5) Average noise level in high floor is over 70L_eq dB(A) at day and night time, so more detailed soundproofing countermeasured in high floors apartment is required.
3.
1997.02
서비스 종료(열람 제한)
The objective of this study was to examine the transient response to hydraulic shocks in an inverse fluidized bed biofilm reactor(IFBBR) for the treatment of apartment sewage. The hydraulic shock experiments, when the system were reached at steady state with each HRT 12, 7, and 4hr, were conducted by changing twice HRT per day during 3days. The SCOD, SS, DO, and pH of the effluent stream were increased with hydraulic shock, but easily recovered to the steady state of pre-hydraulic shock condition. In spite of hydraulic shock, there were not much variation of biomass concentration, biofilm thickness, and biofilm dry density.
4.
1997.02
서비스 종료(열람 제한)
The variations of gas hold-up, overall volumetric oxygen mass transfer coefficients and liquid circulation velocity in an internal loop reactor were investigated to manifest scale-up effect. The relationship between superficial gas velocity and gas hold-up were found as Ugr = 0.045 εr in the pilot-scale and Ugr = 0.056 εr in the bench-scale reactor. The overall volumetric oxygen mass transfer coefficient, K_La was slightly increased in the pilotscale than in the bench-scale reactor. Flow regime was changed from the bubble flow to the churn-turbulent flow when the superficial gas velocity reached to 3.5 - 4 ㎝/sec in the pilot-scale.
5.
1997.02
서비스 종료(열람 제한)
In investigating heavy metal contents at specific areas, the method of selecting sampling points is important. A general method is, according to the law , random sampling of zigzag-form in the selected field. In this work, we studied whether the measured values obtained from a certain method of selecting sampling points is a representative of heavy metal contents in the selected field or not. The selected field for this study is located on the lower Yangsan-river; Gasan-li, Mulgum-myon, Yangsan-gun, KyoungNam. 1 km away from the main stream of Nakdong river. The heavy metals investigated were Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. The inductively coupled plasma(ICP) atomic emission spectrometer was used to measure these metals quantitatively. The number of total sampling points were 24. We compared the total mean values with the mean obtained from various methods of selecting sampling points.
6.
1997.02
서비스 종료(열람 제한)
Methyl methanesulfonate (MMS) was fed to Drosophila melanogaster in order to investigate its toxic capability at developmental and adult stages, and the hereditary effect of toxicity and the potency for induction of sex-linked lethal mutation during the spermatogenesis by the means of an attached-X method.
In the control group, the egg to adult viability of D. melanogaster was 95.2%, while 3.5mM and 5.0mM treated groups were 90.0% and 84.1%, respectively. In the case of their progenies (F_1), the viability was 96.9% in the control group, while 3.5mM and 5.0mM treated groups were 54.5% and 1.6%, respectively. Therefore, these differences between two generations show significant physiological toxic effects in the next generation. In the parental generation, the developmental time was calculated 11.05 days in the control group, 12.43 days in 3.5%mM treated group, and 13.23 days in 5.0mM. In the case of F_1 it was estimated 10.35 days in the control group, and 11.43 days in 3.5mM treated group. Compared with the control groups in two generations, the developmental time generally delayed as the dose of MMS increased. As to the sex-ratio, there was no differences between the control and MMS treated groups. The toxic values of adult stage showed which increased the frequency of mortality with MMS concentrations. The mortality at 120hr in the control group was 1.67% and it in 0.5mM MMS treated group 3.33%. In 2.5mM MMS treated group, it was 33.3% at 72hr, and it 95% at 120hr. The increase of the morality was shown from 72hr in 4.0mM treated group which was 100% at 96hr. There was the concentration-dependent induction of sex-linked lethal mutation during the spermatogenesis by means of an attached-X method, MMS had more pronounced effect in sperm and spermaid stages in D. melanogaster.
7.
1997.02
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The toxicity of purified ricin from Ricinus communis to rats was examined by histological and histochemical methods. Sprague-Dawley rats were injected intraperitoneally with 75㎍/㎏ body weight of ricin and were sacrified at intervals of 6, 24, 48 and 120 hours after injection.
The major morphological changes, such as cloudy swelling, hydropic degeneration, necrosis, fatty change, blood congestion, increase of Kupffer cells in number and extension of sinusoids, were obvious in the liver of experimental group. These morphological changes of hepatic cells were mainly observed in both the periportal and midlobular region of hepatic lobule. The extension of sinusoids was obvious in the centrolobular region. And glycogen distribution of hepatic cells tended to decrease in the same region showing morphlogical changes as compared with the control group.
8.
1997.02
서비스 종료(열람 제한)
Heavy metal adsorption by microbial cells is an alternative to conventional methods of heavy metal removal and recovery from metal-bearing wastewater. The waste Saccharomyces cerevisiae is an inexpensive, relatively available source of biomass for heavy metal biosorption. Biosorption was investigated by free and immobilized-S. cerevisiae. The order of biosorption capacity was Pb>Cu>Cd with batch system. The biosorption parameters had been determined for Pb with free cells according to the Freundlich and Langmuir model. It was found that the data fitted reasonably well to the Freundlich model. The selective uptake of immobilized-S. cerevisiae was observed when all the metal ions were dissolved in a mixed metals solution(Pb, Cu, Cr and Cd). The biosorption of mixed metals solution by immobilized-cell was studied in packed bed reactor. The Pb uptake was investigated in particular, as it represents one of the most widely distributed heavy metals in water. We also tested the desorption of Pb from immobilized-cell by using HCl, H_2SO_4 and EDTA.
9.
1997.02
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Endotoxin from the cell wall of marine V. vulnificus was extracted using the hot phenol-water method, injected endotoxin into rat, and tested the toxic effect of endotoxin on the blood component in rat blood. The results showed that blood glucose, blood urea nitrogen, white blood cell, and reticulocyte were increased and red blood cell was the same as the number of control group(normal blood), but platelet was decreased. Above results suggested that endotoxin induced a malfunction of liver and that the increase of white blood cell was for the removal of foreign toxic substance.
10.
1997.02
서비스 종료(열람 제한)
The rates of photodegradation, reactivities, and mechanisms of photooxidation for the aqueous solution containing with halogen derivatives of aliphatic hydrocarbons have been discussed with respect to the kinds of photocatalysts, concentration of photocatalytic suspensions, strength of radiant power , time of illumination, changes of pH of substrate solution, wavelength of radiation, and pressure of oxygen gas saturated in the solution.
These aqueous solutions suspended with 0.5 gL^-1 TiO_2 powder have been photodecomposed in the range of 100 and 93.8% per 1 hour if it is illuminated with wavelength (λ≥ 300nm) produced from Xe-lamp(450W).
The photocatalytic abilities have been increased in the order of Fe_2O_3 < CdS < CeO_2 < Y_O2_3 < TiO_2, and rates of photodegradation for the solution have maximum values in the condition of pH 6∼8 and 3 psi-O_2 gL^-1. These rates for the photooxidation per 1 hour were dependent on the size of molecular weight and chemical bonding for organic halogen compounds and the rates of photodegradation were increased in the order of C_2H_5Br < CH_2Br_2 < C_5H_11Cl C_2H_4Cl_2 < trans-C_2H_2Cl_2 < cis-C_2H_2Cl_2 The t_1/2 and t_99% for these solutions were 5∼21 and 40∼90 minutes, respectively, and these values were coincided with initial reaction kinetics(r_0).
It was found that reaction of photodegradation has the pseudo first-order kinetics controlled by the amount of h^+_VB diffused from a surface of photocatalysts.
11.
1997.02
서비스 종료(열람 제한)
The flora of Mt. KumJung(801m) was investigated to compare the flora of Mt. Hwang-Ryung, Mt. Cheon-Hwang, Mt. Chuiseo. The vascular plants, collected from March 1995 to Oct., 1996, were consisted of a total 564 taxa; 103 families, 312 genera, 493 species, 1 subspecies, 66 varieties and 4 forms. The Korean endemic plants of this area were 11 taxa, the alpian and endangered plants were 29 taxa, the special wild plants designating by Environmental Agency were 2 taxa and the alpian plants were 18 taxa. Because many plants, being necessary to conserve, are distributed KumJung, but if development is indespensable, destruction of natural ecosystem must be minimized.
