• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.332-338
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• 2010

Degradation characteristics of insecticide diazinon in upland and paddy soils under laboratory conditions were investigated to elucidate the effect of raw pig slurry (RPS) and processed pig slurry (PPS) treatment. Soil (20g) was treated with RPS and PPS by standard rate, double rate and triple rate before treating with diazinon (0.5mg/kg level) and incubating at ($25{\pm}2^{\circ}C$) for 60 days. The half-lives of diazinon in the untreated upland and paddy soil were about 28 and 22 days respectively. The degradation rate of diazinon was faster by $5.0{\pm}1.2$ days in the paddy soil than in the upland soil independent of fertilizer types. This result indicates that soil moisture content affects the half-life of diazinon probably by hydrolysis. Degradation of diazinon was faster in RPS treatment soil than in PPS treatment soil. The more amount of fertilizers were treated, the more rapidly diazinon degraded regardless of fertilizers and soil types. Based on the results obtained, degradation of diazinon in soil was definitely influenced by soil water contents and treatment of those fertilizers.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.53-56
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• 2005

A Laboratory study was conducted to evaluate the kinetics of oxidation of trichloroethylene (TCE) in groundwater by potassium permanganate $(KMnO_4)$, Consumption of permanganate by TCE and aquifer materials was also evaluated to obtain an appropriate injection rate of $KMnO_4$. TCE degradation by $KMnO_4$ in the absence of aquifer material showed effective with pseudo-first order rate constant, $k_{obs}=1.8110^{-3}\;s^{-1}\;at\;KMnO_4=500mg/L$. TCE oxidation by $KMnO_4$ was found to be second order reaction and the rate constant, $k=0.65{\pm}0.08\;M^{-1}s^{-1}$, was independent of pH changes. $KMnO_4$ consumption rate by groundwater sampled from field site was not significant, indicating that groundwater containing negligible amount of dissolved organic matter does not have any influence on the $KMnO_4$ degradation. Meanwhile, aquifer materials from field site were actively reacted with permanganate, resulting in the significant consumption of $KMnO_4$. It might be attributed to the existence of metal oxides in aquifer materials, Based on the rate constants obtained from this study, appropriate injection rate of permanganate and TCE removal rate in groundwater could be estimated.

• Journal of Life Science
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• v.19 no.12
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• pp.1731-1736
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• 2009

Recent studies determined that a chronic western-style diet increased the endogenous small heterodimer partner (SHP) protein levels in mice. In experiments with cell cultures, chenodeoxy cholic acid (CDCA) treatment increased endogenous SHP protein levels and reduced the degradation rate of exogenously expressed flag-SHP levels in the human hepatoma cell line, HepG2 cells. In addition, bile acid-induced intestinal fibroblast growth factor-19 (FGF-19) increased the half-life of the exogenously expressed SHP when HepG2 cells were transfected with ad-flag-SHP. However, both the expression level and the degradation rate of the endogenous SHP in response to cholic acid and FGF-19 have not been well understood, either in mice or in cultured HepG2 cells. This study examined the effects of cholic acid treatment on the endogenous SHP protein levels in mice and the effects of FGF-19 on the degradation rate of the endogenous SHP protein in HepG2 cells. Mice fed 0.5% cholic acid in normal chow showed an increase in endogenous SHP protein levels during both 12 hr and 24 hr treatment periods as compared to control mice fed only normal chow. In cultured HepG2 cells, treatment with CDCA did not noticeably change the rate of degradation in the endogenous SHP protein from cells not treated with CDCA. Although consistent with the previous studies on the exogenous ad-flag-SHP protein, treatment with FGF-19 significantly decreased the degradation rate of the endogenous SHP protein when HepG2 cells were treated with cyclohexamide. These results suggest that both bile acids and FGF-19 increase the endogenous SHP protein levels in mouse liver and HepG2 cells.

• Journal of Urban Science
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• v.8 no.2
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• pp.29-34
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• 2019

Benzene pollution is becoming increasingly serious, and the treatment technology of benzene has attracted much attention. In this paper, a self-made photocatalytic reactor was used to explore the removal rate of benzene under the ultraviolet light with the wavelength of 253.7nm. The results showed that the degradation rate of benzene decreased from 64.29% to 16.26% when the concentration increased from 43mg/㎥ to 256mg/㎥ under the condition of 28W UV light intensity and 50s residence time. Under the condition of 28W UV light intensity and 103mg/㎥ concentration, the residence time increased from 16.5s to 50s, and the benzene removal rate increased from 13.23% to 42.72%.Under the condition of benzene concentration 103mg/㎥ and residence time of 50s, the removal rate of benzene increased from 29.34% to 52.58% in the process of UV light intensity rising from 28W to 48W.It is concluded that decreasing the concentration and increasing the residence time of gas were beneficial to the removal of benzene and increasing the light intensity can improve the removal rate of benzene.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.218-222
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• 2004

Batch slurry experiments were conducted to develop cement/slag/Fe(II) system that could treat hazardous liquid wastes containing halogenated organic solvents. Portland cement in combination with Fe(II) was reported to reductively dechlorinate chlorinated organics in a modified solidification/stabilization process. TCE (trichloroethylene) was used a model halogenated organic solvent. The objectives of this study were to assess the feasibility of using cement and steel converter slag amended with Fe(II) as a low cost abiotic reductive dechlorination and to investigate the kinetics of TCE dechlorination over a wide range of TCE concentration. From the result of screening experiments, cement/slag/Fe(II) system was identified as a potentially effective system to treat halogenated organic solvent. Kinetic studies were carried out to further investigate degradation reaction of TCE NAPL (Non Aqueous Phase Liquids) in cement/slag/Fe(II) systems by using batch slurry reactors. Degradation rate of TCE solution in this system can be explained by pseudo-first-order rate law because the prediction with the rate law is in good agreement with the observed data.

• Journal of Pharmaceutical Investigation
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• v.33 no.1
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• pp.37-43
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• 2003

The objective of this study is to prepare ketoprofen (KP) - poly(ethylene glycol) (PEG) conjugates and to investigate their degradation kinetics. KP-PEG conjugates were synthesized from KP and PEG methy1ester by esterification in the presence of DCC. The KP-PEG conjugates (KPEG) were characterized by IR and $^{1}H-NMR$ spectroscopy. The hydrolysis of KPEG with time was studied using HPLC by simultaneous quantification of KP and KPEG. The hydrolysis rate constant was high at low and high pHs, and showed minimum at pH 4 and 5. As the size of KPEG increases, hydrolysis rate increased. The slope of degradation rate profile suggests that catalytic reaction seems to occur by specific acid/base catalysis. These results suggest that KPEG could be used as a prodrug for KP, which releases KP slowly in the body.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.659-664
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• 2007

The objective of this study is to evaluate the detoxification method for the endocrine disrupting chemicals by manganese oxide. Manganese coated sand and bisphenol-A (BPA) was used as the reactive medium and the contaminant. Results showed that manganese oxide effectively degrades BPA by oxidative coupling reaction. The nonlinear oxidative coupling reaction orders were obtained for BPA and oxide, respectively. The reaction rate of BPA decreased as initial BPA concentration increased, as oxide loading decreased and as pH increased. The higher ionic strength, the higher reaction rate was observed. Divalent cations were adsorbed on the oxide surfaces, resulting in the decreased degradation rate of BPA.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.4
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• pp.427-432
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• 2001

The purpose of study is to examine the sensitivity of the rate of degradation to initial TCE concentration and iron concentration in the solution. The batch tests were executed to assess the degradation rate at varying initial conditions. First order rate constants($k_a$) were more rapid with the lower initial TCE concentration, Howere the correleation was not always linear between $k_a$ and initial TCE concentration. $k_a$ was proportionally increased as the increasing surface area. It implied that the effective reactive surface area acted as the limiting factor on the reductive dechlorination of TCE by iron.

• Tribology and Lubricants
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• v.17 no.3
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• pp.171-178
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• 2001

In order to elucidate the lubricating mechanism of polyolester base oils [POEs], the wear characteristics of 27 kinds of polyolester base oils including mixed POEs were investigated. Their wear results were discussed in terms of the effect of molecular structure on wear performance and compared with those of mineral oil. In addition, the adsorption ability of POEs to reduced iron and their hydrolysis rates were measured and the effect of their molecular structures on the adsorptivity and hydrolysis rate of POEs was discussed, respectively. Finally, the lubricating mechanism anlyzed from these results of wear characteristics, adsorptivity and hydrolysis rate was proposed. That is to say, POEs are firstly adsorbed to friction surface and decomposed by hydrolysis or thermal degradation. Fatty acids obtained by degradation of POEs form adsorption film on friction surface. The larger become cohesive ability among fatty acid molecules in the adsorption film, the better gets the wear performance of POEs.

• Journal of environmental and Sanitary engineering
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• v.15 no.4
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• pp.98-104
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• 2000

Commercial rubber(IR, NR, BR), SBR, and tire were degraded by thermal degradation process. The oil yield of rubbers and tire ranges about 37~86%, it was increased with increase of operation temperature in pyrolysis. And the yield of pyrolytic oil was increased with increase of heating rate. The maximum oil yields of IR, NR, BR, SBR, and tire were 80, 73, 83, 86 and 55% each at $700^{\circ}C$ with a heating rate of $20^{\circ}C$/min, respectively. The pyrolytic oil components were consisted of about 50 aromatic compounds. The calorific value of purolytic oil of commercial rubber, SBR, and tire was measured by calorimeter, it was 39~40 kJ/g. The BET surface area of pyroblack was $47~63m^2/g$. The optimum condition of pyrolysis was operating temperature of $700^{\circ}C$ with heating rate of $20^{\circ}C$. Therefore, the pyrolytic oil and pyroblack are possible to alternative fuel and carbon black.