• Corrosion Science and Technology
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• v.22 no.6
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• pp.429-434
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• 2023

This study investigated the localized corrosion behavior of a UNS G41400 steel surface treated with manganese phosphate. The phosphate coating, primarily composed of oxygen (O), phosphorus (P), and manganese (Mn) elements, had an approximate thickness of 6 ㎛. The particles comprising the coating varied in size by several micrometers; smaller particles were mainly composed of O, P, Mn, and iron (Fe) elements, indicating incomplete formation of the manganese phosphate film. Potentiodynamic polarization curves revealed a decrease in anodic current after surface treatment and a shift in corrosion potential toward the noble direction after treatment. After immersion in a 3.5 wt% NaCl solution for 96 hours, localized corrosion was observed, with some regions retaining residual phosphate film. Even though localized corrosion occurred on the treated surface, it was less severe than that on the untreated UNS G41400 steel surface. These findings suggest that manganese phosphate coating improved resistance to localized corrosion.

• Korean Journal of Agricultural Science
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• v.5 no.2
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• pp.80-86
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• 1978

This study was carried out in order to know the effect of T. T. C. reaction on antibiotics, cleanser, disinfectants, pH, acidity and station of culture a bacterial Streptococcus thermophilus was used to 2.3.5-triphenyl tetrazolium chloride reduction test for the detection of residual antibiotics in milk were tested. The results obtained were summarized as follows. 1. The T. T. C. reaction was most sensitive in the group of penicillin as 0.02~0.05 IU and also it was less sensitive in Streptomycin and various broad antibiotics except Vibramycin, Synthomycin and Teramycin but it was least sensitive in Streptomycin group. 2. For ther T. T. C. reaction test on cleanser, the positive reaction was appeared above 0.7% of Hi-Ti and 0.1% of NaOH solution respectively. 3. For the T. T. C. test reaction on disinfectants, the positive reaction was occured on 200~500 ppm solution of sodium-hypochlorite and chloride-lime, 0.15~0.35% solution of phenol, cresol and Iode-K. 4. The optimum temperature was $35{\sim}37^{\circ}C$ and proper culturing time was 12 to 18 hours for propagation culturing. 5. The suspect positive reaction was tested above pH 5.0 and the positive reaction was appeared above 0.21% of acidity.

• Journal of Mushroom
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• v.18 no.4
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• pp.380-386
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• 2020

The study was conducted for the safety evaluation of 320 pesticide residues in 768 Lentinula edodes fruit body samples and 143 L. edodes media samples, which are distributed nationwide in South Korea. The monitoring method was the second of the multi-residue methods in the Korean Food Code. GC-ECD, GC-NPD, and GC-MSD were used as evaluation equipment for analysis. Single-analysis of the target pesticides was performed for mepiquat chloride. Through the analysis of collected L. edodes samples, pesticide residues were detected in total seven cases, including four L. edodes fruit body samples and three L. edodes media samples. The detected pesticide residues were carbendazim, diflubenzuron, fluopyram, and dinotefuran. In this study, carbendazim was detected in three L. edodes fruit body samples and one L. edodes media sample. The detected amount of carbendazim was 0.056, 0.17, 0.043, and 0.09 mg/kg, respectively. The amount of carbendazim in the collected L. edodes samples was detected below the MRLs (maximum residue level). The detected amounts of fluopyram and dinotefuran were 0.068 mg/kg and 0.06 mg/kg, respectively. Two pesticide residues were detected in the medium in one case. Mepiquat chloride was not detected in this study. These results suggested that residual pesticides were detected in a small number of collected L. edodes. However, the PLS for unregistered pesticides MRL was 0.01 ppm; therefore, we have to conduct research on preparing safety standards for mushrooms, including L. edodes.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.9
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• pp.900-904
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• 2010

Polyvinyl chloride (PVC) hoses, polyethylene hose and silicone hose for tap water were tested with respect to migration of phenolic compounds to water. The highest concentrations (0.36~1.97 mg/L) of total phenolic compounds were observed in the test water from PVC hoses. Increasing residual Cl concentration from 0 to 0.5 mg/L or increasing water temperature from 4 to $25^{\circ}C$ increased 3~3.2 times and 100~104 times for migrated total phenolic compounds concentrations, in respectively. A major migrating phenolic compounds from PVC hoses were bisphenol-a (BPA) and it was observed that the concentration of migrating phenolic compounds in the order: DEHP > 2-chlorophenol > 2,4,6-trichlorophenol > 2,4-dichlorophenol from PVC hoses.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2000.04a
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• pp.118-118
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• 2000

New single-source precursor, [AlCI3:NH2tBu] was synthesized for AlN thin f film processing with AICI3 (Aluminum Chloride) and tBuNH2 (tert-butylamine). AlN thin films for packaging aspplication were deposited on sapphire substrate by a atmosph하ie-pressure MOCVD. In most of other study methyl-based AI precursors w were used for source, But herein Aluminum Chloride was used for as AI source i in order to prevent the carbon contamination in the films and stabilize the p precursor. New precursor showed the very high gas vapor pressure so it allowed to m make the film under atmospheric-pressure and get the high purified film. High q quality AlN thin film was obtained at 700 to $900^{\circ}C$. The new precursor was p purified by a sublimation technique and help to fabricate high purity film. It s showed high vapor pressure, which is able to a critieal factor for the high purity a and atmospheric CVD of AlN. High Quality AIN thin film was obtained at $700-900^{\circ}C$. The AIN film was characterized by RBS

• Microbiology and Biotechnology Letters
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• v.5 no.3
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• pp.153-158
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• 1977

These experiments were conducted to investigate the condition of the production and the heat resistance of the acid protease by Rhizopus japonicus S-62. The results obtained were as follows: 1) The optimum concentrations of sucrose, yeast, ammonium chloride and sodium phosphate monobasic added to the wheat bran medium in the acid protease production were 0.5％, 2.0％, 0.4％, and 0.4％, respectively. 2) KH$_2$PO$_4$ and NaH$_2$PO$_4$ were the most effective as the heat resistant agents. 3) When the enzyme solutions added with KH$_2$PO$_4$ and NaH$_2$PO$_4$ to the concentration of 2％ were heated for 10 min, at 50$^{\circ}C$, their residual activities were 100％, respectively. 4) The heat resistant effects of KH$_2$PO$_4$ and NaH$_2$PO$_4$ were not observed almost above 55$^{\circ}C$.

• Journal of the Korean institute of surface engineering
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• v.18 no.3
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• pp.125-133
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• 1985

About 1 mm thick nickel electrodeposits were obtained from nickel sulphamate baths at 40 to 60$^{\circ}C$ over the range of current densities form 5 to 25 A/$dm^2$. Deposits from above about 1.2V of cathode overpotential had randomly distributed fine grains due to a higher nucleation rate and hence had a high hardness. A deposit obtained at 0.63 V had the [110] orientation with a field oriented fine structure which yield a relatively high hardness. Deposite obtained at the intermediate overpotentials showed the [100] orientation with coarse field oriented structure whose column width tended to decrease with increasing cathode overpotential, which, in turn, gave rise to an increase in hardness. Residual stresses of the deposits measured by X-ray technique were mostly tensile but did not exceed 80 MPa, and were occasionally very small compressive. The cathode current efficiency was above 90% in all the electrolysis conditions, whereas the anode current efficiency varied from 50 to 90% with current density, bath temperature and nickel chloride concentration, among which the chloride was the most influential.

• Korean Journal of Environmental Agriculture
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• v.42 no.3
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• pp.184-192
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• 2023

Microplastics are generated by the breakdown of plastic wastes in agricultural soil and residual pesticides in agricultural soil can adsorb on microplastics. In this study, the sorption characteristics of procymidone (PCM) and one of its metabolites, 3,5-dichloroaniline (DCA), on low-density polyethylene (LDPE) and polyvinyl chloride (PVC) microplastics were investigated. The sorption and desorption tests were carried out for 72 h using LDPE or PVC microplastic films to study the sorption isotherms of PCM and DCA and kinetics for sorption and desorption of PCM. The results show that the sorption data of PCM and DCA were better described by the Freundlich isotherm model (R²=0.7568-0.9915) than the Langmuir isotherm model (R²=0.0545-0.5889). The sorption potential of PVC for both PCM and DCA was greater than that of LDPE. The sorption data of PCM on PVC and LDPE were fitted better to the pseudo-second-order kinetic model than the pseudo-first-order kinetic model. The PCM sorption on LDPE was about three times faster than that on PVC. Both microplastic films released the sorbed PCM back to water, and more PCM was released from PVC than LDPE, but the desorption rate was faster with LDPE than PVC. Overall, the results show that different microplastics have different sorption characteristics for different chemicals. Also, the sorbed chemicals can be released back to environment suggesting the potential of contaminant spread by microplastics. Thus, the management practices of microplastics in agricultural soil need to consider their interaction with the chemical contaminants in soil.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.1
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• pp.71-78
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• 2006

The removal of protozoa in the coagulation process was evaluated under the different pH and turbidity using the jar test after the addition of polyaluminium chloride (PAC) as a coagulant. Two well-known protozoa of Cryptosporidium parvum and Giardia lamblia were tested at the same time with turbidity, the critical water quality parameter of the water treatment process. Both protozoa were removed about 1log (and up to 2log) at the optimum injection of PAC. The source water turbidity and pH affected the removal of protozoa and turbidity. At neutral and alkaline pH, 1.3-1.7log removal of protozoa for low turbid water with 5NTU, and 1.6-2.3log removal for high turbid water with 30NTU were achieved. However, at acidic pH, maximum 0.8-1.0log and 1.1-1.2log were removed for low and high turbid water, respectively, at the optimum PAC injection of 15mg/L. The relation of protozoa and turbidity removals were expressed as the 1st order equation (significantly positive relation) in the most of the tested conditions. In addition, the relation of protozoan removals with residual turbidity were also expressed the 1st order equation (significantly negative relation), although the significance of the equations were reduced at acidic pH. Therefore, residual turbidity could be a good index of efficient protozoan removal in the coagulation process, probably except at the low pH condition.

• Journal of Soil and Groundwater Environment
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• v.15 no.5
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• pp.23-31
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• 2010

For an efficient remediation of Pb-contaminated soil (S-1) in a clay shooting range, a soil washing test was performed with mineral acid, organic acid, chelating agent, and chloride. The Pb extraction efficiency of extractant (0.1 M) used in the washing test showed the order of HCl > $Na_2$-EDTA > NTA > DTPA > citric acid > malic acid > succinic acid > acetic acid > $CaCl_2$ > $MgCl_2$, for S-1 soil. As compared to initial Pb concentration, extraction efficiency by the concentration of extractant was 93.35%, 80.80%, 73.92%, and 24.57% in S-1 soil for HCl (0.5 M, pH 1.10), $Na_2$-EDTA (0.01 M, pH 3.99), citric acid (0.5 M, pH 1.27), and $MgCl_2$ (0.1 M, pH 8.82), respectively. S-1 soil had 56.83% of residue form and 43.17% of non-residue form (18.04% of exchangeable form), respectively. Although the concentrations of these fractions sharply decreased after HCl washing, since the exchangeable forms with relatively large mobility are still distributed as high as 18.78% (to Pb total content in residual soils) in S-1 soil, it is necessary to devise a proper management plan for residual soils after soil washing application.