• Journal of Electrochemical Science and Technology
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• v.8 no.1
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• pp.77-86
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• 2017

The valorization of domestic wastes becomes a very important research axis that can reduce the energy consumption and protect our environment. The objective of this study is to remove zinc ions from wastewater by using banana peels after their activation as sensor in the working electrode for an environmental application. Banana peels were dried, crushed and treated with sulfuric acid then mixed with polyaniline to improve their electrical conductivity. Cyclic voltammetry and chronoamperometry were used for electrochemistry tests. The obtained voltammogramms at well optimized conditions of applied potential of -1.3 V/SCE and initial zinc concentration of 0.2M during 2 hours of electrolysis, showed the reduction peak of the zinc at a potential of -1.14 V/SCE, which confirmed the activity of this electrode. The modeling of experimental data revealed that the adsorption was fitted by the Langmuir isotherm with a maximal adsorption capacity of 3.4188 mg/g. Changes in the structure of the powder after the electrosorption was noticed by SEM and EDX. Finally, the dosage of the electrolytic solution showed a diminution of the zinc concentration with yield of 99.99%.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.30-31
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• 2015

Usually, carbonation of concrete causes pH reduction and corrosion of steel, it leads to decrease of durability. However, CaCO₃, as results of reaction with hydrates products and CO₂, can contribute to improvement of compressive strength. Based on this theory, using carbonation depth, the researches about CO₂ absorption of plain concrete and concrete containing CO₂ reactive materials has been performed. But, the researches has limitation about using one material, therefore, for this study, considering various CO₂ reactive materials, experiment has been proceeded. With water to binder ratio 50%, after initial curing for 2days, accelerated carbonation was performed for 28days, and carbonation depth and compressive strength were measured. As results of carbonation depth, specimen containing desulfurized slag, zeolite showed the highest CO₂ absorption, in case of compressive strength, specimens with MgO were indicated as highest compressive strength.

• YAKHAK HOEJI
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• v.42 no.4
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• pp.382-387
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• 1998

Platycodon radix is a dried root of Platycodon grandiflorum (P. grandiflorum) A. DC, a perennial grown on the hills and fields in Korea and Japan, or cultivated in various districts. Recently, P. grandiflorum (Changkil) has been successfully cultivated for more than 20 years and generally has been employed as folk remedy for adult diseases such as hyperlipidemia, hypertension and diabetes. We investigated various biological activities of the extracts from Changkil. When treated in vitro with B16-F1 mouse melanoma cell lines, it showed 100% laminin-binding inhibitory activities at the concentration over 0.125mg/ml. In in vivo test it showed 61.5% reduction of the solid tumor weight transplanted in mice and exhibited anticancer activity of 128% ILS against Sarcoma-180 ascites. It also increased the ratio of positive cells of natural killer cells in lymphocytic composition against Sarcoma-18O ascites and solid tumor transplanted in ICR mice when tests were carried out by FACScan method.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.1
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• pp.49-55
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• 2017

Chinese cabbage cultivation and ammonia volatilization experiments were done to evaluate the efficiency of Agrotain coated urea (GSP 80% + Agro; GSP 100% + Agro) against conventional urea (GSP 80%; GSP 100%). Fresh weight of Chinese cabbage were 17.2% and 7.3% higher in the treatments that received GSP 80% + Agro and GSP 100% + Agro, respectively, of those from the treatments that received urea alone. Likewise, the nitrogen use efficiency of Chinese cabbage in the treatments that received Agrotain coated urea were significantly higher at the rate of 3.5% (GSP 80% + Agro) and 1.9% (GSP 100% + Agro) compared to urea alone treatments. Ammonia emission was substantially higher at the rate of $107.6N\;mg\;chamber^{-1}$ with the application of only GSP 100%. However, nearly 28.3% of ammonia emission was considerably reduced with the use of Agrotain coated urea. Hence, we recommend the use of Agrotain coated urea in conventional farming for increased crop yield as well as simultaneous reduction of nitrogenous fertilizer use.

• Journal of Magnetics
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• v.14 no.1
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• pp.7-10
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• 2009

In this work, we studied the effects of Sn addition on the ordering temperature of FePt thin film. The coercivity of FePtSn film was about 1000 Oe greater than the coercivity of FePt film for an annealing temperature of $600^{\circ}C$. Therefore, Sn addition was effective in promoting the $L1_0$ ordering and in reducing the ordering temperature of the FePt film. From our X-ray diffraction results, we found that in the as-deposited film, the addition of Sn induced a lattice expansion in disordered FePt thin films. After the annealing process, the excess Sn diffuses out from the ordered FePt thin film because of the difference in the solid solubility of Sn between the disordered and ordered phases. The existence of precipitates of Sn from the FePt lattice was deduced by Curie temperature measurements of the FePt and FePtSn films. Therefore, the key role played by the addition of Sn to the FePt film can be explained by a reduction in the activation energy for the $L1_0$ order-disorder transformation of FePt which originates from the high internal stress in the disordered phase induced by the supersaturated Sn atoms.

• Journal of Plant Biology
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• v.36 no.1
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• pp.113-120
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• 1993

Effects of various NaCl concentrations on salt-tolerant callus of tobacco were investigated. Selection of NaCl-tolerant (S) callus was conducted by subculturing Nicotiana tabacum cv. BY 4 callus in 200 mM NaCl-containing MS medium for more than 18 months. In spite of the long subculture period, characteristics of salt tolerance were maintained very stably. Significant differences were found in ion contents of each callus which was subcultured with treatment of various NaCl concentrations: Na+ and Cl- became higher but Mg2+, Ca2+ and K+ became lower with the increasing external salt contents. Therefore, the ratios of Na+/Ca2+ and Na+/K+ also increased resulting close to those of halophytic property. The contents of chlorophylls and carotenoids in S callus were estimated to 3.1 and 2.9 times more, respectively. than those of non-selected (NS) callus (control). The higher content of external NaCl tended to increase the amount of water soluble proteins and to decrease the amounts of the total sugars, reducing sugars and free amino acids. The activity of peroxidase was increased with higher contents of external NaCl in S callus, but it was maintained at a higher level than S callus at lower NaCl, followed by a subsequent decrease above 80 mM NaCl in NS callus. These results suggest that S callus may have a biological system converting energy source to efficient growth leading to reduction of the growth inhibition under stress environment.

• YAKHAK HOEJI
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• v.30 no.3
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• pp.143-148
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• 1986

The effect of orally administered ginseng ethanol extract on potassium deficient and normal rat skeletal muscles was investigated in terms of Ca uptake by sarcoplastic reticulum fragments. The ginseng ethanol extract (100mg/kg/day) was administered orally to Sprague-Dawley rats for 21 days and their changes of body weights, $K^+$ content in skeletal muscles, and calcium uptake capacity of sarcoplamic reticulurn of each groups were measured. The growth rate of rats fed with the potassium deficient diet was significantly decreased compared to that of normal rats. Ginseng components did not show any effect on the decreased growth rate of the postassium deficient rats. Potassium content in skeletal muscle from potassium deficient rats was significantly reduced compared to that of normal rats. Ginseng components showed the tendency to prevent the reduction in potassium content of potassium deficient rats, but differences were not statistically significant. Calcium uptake of SR prepared from skeletal muscles of potassium deficient rats was increased significantly compared to that of normal rats. Ginseng components prevented such increase of calcium uptake by 30%. In summary, it can be concluded that ginseng may prevent the increase in Cauptake of SR obtained from potassium deficient rats.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.3
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• pp.572-578
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• 1999

This study was conducted to investigate processing condition and characteristics of chestnut paste. The kinds of chestnut powder processed with blanching and drying of raw material were four named RH(not blanched, hot air dried), RF(not blanched, freeze dried), BH(blanched, hot air dried) and BF(blanched, freeze dried). Blanching affected the reduction of drying time in chestnut. Water absorption index of the blanched samples were higher than the nonblanched. Blanching affected the viscosity of pastes when water was added to process paste also, but drying methods did not affected to it. The proper ratio of water to the powder to process paste was 1.3 to 1.5 times in RH and RF, whereas 2.7 times in BH and BF by sensory evaluation. Soluble tannin content of paste was higher in RF and RH paste than BF and BH. Vitamin C content was the highest(88.49mg/100g) in RF paste and reducing sugar content was the highest in RF paste. Hunter's L and a values were the highest in BF and RH pastes, respectively, among the all paste samples. Volatile compounds detected from chestnutpastes were hydrocarbons, alcohols, phenols, ketones. The major volatile compound in all the pastes was 2,6 bis(1,1 dimethylethyl) 4 methyl phenol.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.197-201
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• 2002

This paper presents optimized design, fabrication and thermal characteristics of micro-heaters for thermal MEMS (micro electro mechanical system) applications using SOI and trench structures. The micro-heaters are based on a thermal measurement principle and contains thermal isolation regions of 10 ${\mu}m$-thick Si membranes consisting of oxide-filled trenches in the SOI membrane rim. The micro-heaters were fabricated with Pt-RTD on the same substrate via MgO buff layer between Pt thin-film and $SiO_2$ layer. The thermal characteristics of micro-heater with trench-free SOI membrane structure was $280^{\circ}C$ at input power 0.9 W; in the presence of 10 trenches, it was $580^{\circ}C$ due to reduction of the external thermal loss. Therefore, a micro-heater with trenches in SOI membrane rim structure provides a powerful and versatile alternative technology for enhancing the performance of micro-thermal sensors and actuators.

• Environmental Engineering Research
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• v.10 no.6
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• pp.294-305
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• 2005

The effectiveness of fly ash-, quicklime-, and quicklime-fly ash-based stabilization/solidification(S/S) in chromium(Cr) contaminated soils was investigated using modified semi-dynamic leaching tests. Artificial soil samples composed of kaolinite or montmorillonite contaminated with chromium nitrate(4000 mg $Cr^{3+}\;kg^{-1}$ of solid) were prepared and then subjected to S/S treatment using quicklime, fly ash, or quick lime-fly ash. The effectiveness of the treatment was evaluated by assessing the cumulative fraction of leached $Cr^{3+}$ as well as, by computing the effective diffusivity ($D_e$) and the leachability index (LX) of the treated samples. The reduction in $Cr^{3+}$ release for the untreated samples was more pronounced in the presence of montmorillonite, which was attributed to sorption. Treatment with quicklime, fly ash, or quick lime-fly ash was significantly effective in reducing $Cr^{3+}$ release most probably due to the formation of pozzolanic reaction products and $Cr(OH)_3$ precipitation. The most effective treatment was observed in montmorillonite-sand soil samples treated with quicklime-fly ash (99.8% removal). The mean $D_e$ decreased significantly and the mean LX was greater than 9 for all treated samples, indicating that the treated soils were acceptable for "controlled utilization". The mechanism controlling $Cr^{3+}$ leaching from all treated samples during the first 5 days appeared to be diffusion.