• Applied Chemistry
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• 제15권1호
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• pp.81-84
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• 2011

Platinum catalyst activity and stability is excellent in terms of fuel cells as a catalyst here. Although it is widely used, to compensate for the high price issue non-precious fuel cell catalysts are being developed. In this study, Co/PANi/CNT composite and non-precious as a catalyst for oxygen reduction was applied. Polyaniline on the interaction between cobalt and the oxygen reduction reaction and the structural characteristics observed in the impact and heat treatment was carried out according to the improved catalytic performance. Potential range is oxygen reduction reaction 0.55 V to 0.78 V(vs. NHE) after pyrolysis. Through this study, Co /PANi/CNT composites as a potential catalyst for fuel cells were non-precious.

• Journal of Korean Society for Atmospheric Environment
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• 제7권3호
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• pp.219-226
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• 1991

Results from study on physiological responses to $SO_2$ of Quercus spp. selected for restoration of vegetation damaged by air pollution in the field study were as follows. Tolerance of Quercus aliena, Q. acutissima and Q. mongolica used in this study to $SO_2$ was higher in that order and tolerance of these plants to $SO_2$ was high comparatively among trees composing of major forest vegetation of Korea including natural forests and plantations. Stomatal resistance of these plants was increased after exposure to $SO_2$ and range of increase was different among species. From discrepancy between order of tolerance to $SO_2$ and range of increase in stomatal resistance, we were estimated that resistance mechanisms of Quercus spp. were different among species as mechanism originated in avoidance and resistance, respectively. Water potential of plant leaves reduced after exposure to $SO_2$, degree of reduction accorded with order of tolerance to $SO_2$. Reduction of water potential of plants after exposure to $SO_2$ was initiated before appearance of visible damage in plant leaves and water potential of plants exposed to $SO_2$ of low concentration, in which plants were not showed viaible damage was also reduced.

• Health Policy and Management
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• 제7권1호
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• pp.1-31
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• 1997

In many people's minds, health promotion is simply a more modern term covering roughly the same field as disease prevention or life style related reduction of the risk factors of chronic disease. A review of the modern literature of health promotion make it clear that there is more to this term than what is involved in functioning as a synonym for disease prevention. Therefore, in order to reach a clear understanding of what health promotion is, this study suggest the concept of the health balance model. Health balance is represented in terms of an equilibrium between physical, social, and life-style-related health challenges on the one hand and health potential on the other hand. Thus, health promotion strategies encompasses both the reduction of health challenges and the strengthening of health potential. Many elements of reducing health challenge are mainly related to the regulation laws. Aspects of strengthening of health potential are related to activities of health center. Therefore, health promotion strategies at a community level should be included in regional health planning which is implemented by health center.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제13권4호
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• pp.785-796
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• 2009

In this paper, propose for mobile robot path planning and the reduction in sleep caused by a sleep history suggested a way to compensate for record sensor error. The proposed path plan reduces the robot slip to smooth a potential barrier in the potential field method, and compensates the tachometer error by robot slip using the fuzzy logic system. The efficiency of the proposed method is verified by means of simulations and experiments for path plan and slip revision.

• Journal of Environmental Science International
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• 제15권5호
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• pp.493-501
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• 2006

The increase in environmental loads and energy consumptions has resulted in the need of developed new forms of energy for a sustainable use for the society. Recently, the viability of using unused energy has attracted a great deal of attention. From the view point of using unused energy, the most critical problem can be referred to as the distance between the heat source/sink and heat demand area. The water resource in the city water system was used to solve this distance problem with unused energy. The calculation method of the potential use unit was used to survey the potential of the water resource in the city water system. The amount of theoretical unused energy and energy savings in the model city were estimated using this method. It is estimated that the amounts of energy savings and $CO_2$ reduction correspond to 131.3 GWh and 29280[t-C], respectively, per annual basis.

• The Transactions of the Korean Institute of Electrical Engineers
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• 제40권9호
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• pp.883-892
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• 1991

This paper presnets the characteristics of electropolymerization and electrochemicla propoerties of polyaniline(PAn). From the morphology study on the PAn surface, it seems that coagulation of the fibrils on the surface proceeds as the PAn grows, resulting in fibril clusters with new branches and more extensive voids. While PAn/Li cell is cycled at potential range between 2.9V and 3.7V in which the first strong reduction peak of 2.75V does not appear, its oxidation reduction capacities were increased up to about tenth cycle. Electricity efficiency of stable charge-discharge to deep discharge in PAn/Li cell was 42.9%. Average charge potential, avergae discharge potential, energy density, and charge-discharge energy efficiency of the PAn/Li cell were 3.4V, 3.25V, 132.9Wh/kg, and 95.6%, respectively.

• Proceedings of the KSR Conference
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.443-450
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• 2001

This paper shows the reduction effect of tile earthquake-induced liquefaction potential of soils that improved by Vibro-Replacement Stone Columns. The Vibro-Replacement Stone Columns method transforms soft cohesive soils into a composite mass of compacted granular or crushed stone columns by using vibrating equipment and water jets. This study investigated and analyzed the behavior of the stone columns and composite ground using the results of in situ test and measurement at the job-site. This paper shows the evaluation of the earthquake-induced liquefaction potential of soils using in situ test. There are different types of in situ test used in the evaluation the liquefaction potential. In the particular study the Standard penetration test, and Cone penetration test were used. The N value of Standard Penetration test has been used all over for a very long time. The evaluation of the liquefaction of soil was performed using the worldwide renewed Cone penetration test

• Journal of the Korean Ceramic Society
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• 제48권3호
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• pp.205-210
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• 2011

The dependence of sulfur redox behavior and its diffusivity on temperature and composition was studied in mixed alkali silicate melts by means of square wave voltammetry (SWV) at different frequencies in a temperature range of $1000^{\circ}C$ to $1400^{\circ}C$. The voltammograms showed two reduction peaks at high frequency but only one peak at low frequency. Irrespective of $K_2O/(Na_2O+K_2O)$, each peak potential due to reduction of $S^{6+}$ to $S^{4+}$ and $S^{4+}$ to $S^0$ moved toward a negative direction with temperature decrease, and the peak current showed a strong dependence on frequency at a constant temperature. However, the compositional dependence of the peak potential showed an inconsistent behavior with an increase of $K_2O$. The mixed alkali effect was not observed in sulfur diffusion. This inconsistency of both peak potential and diffusion for compositional dependence may be derived from the strong volatilization of sulfur in melts.

• Korean Journal of Environmental Agriculture
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• 제20권5호
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• pp.346-351
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• 2001

Oxidation of Cr(III) to Cr(VI) can increase availability and toxicity of chromium. In this study, possible mechanisms by which pH and organic matter can control the chromium oxidation and reduction in soil system were examined using four soils of different pHs and organic matter contents. Reduction of Mn-oxides occurred in the soils of higher organic matter content (4.0%), but Mn-oxide was quite stable during the incubation in the soil of pH 7.0 and 0.5% organic matter content. Manganese oxides can be reductively dissolved at lower pH and higher organic matter conditions. The soil of pH 7.0 and 4.0% organic matter content showed the highest Cr-oxidation potential. Reduction of soluble Cr(VI) was observed in all the soils examined. The most rapid reduction was found in soil of pH 5.5 and 4.0% organic matter content, but the reduction was slow in soil of pH 7.0 and 0.5% organic matter content. Thus, the reductive capacity of organic matter added soils was much higher as compared to other two soils of lower organic matter content. In all the soils examined, the reductive capacity of soluble chromium was much higher than the oxidative capacity. Organic matter was found to be the most important controlling factor in the chromium oxidation and reduction. Reduction of Cr(VI) to Cr(III) could be a potentially useful remediation or detoxification process, and availability and toxicity of chromium in soil would be controlled by controlling organic matter content and pH of the soils.

• KSBB Journal
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• 제19권2호
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• pp.154-158
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• 2004

Recycled packed-bed reactor emploring immobilized microorganism was suggested in this paper for efficient denitrification. In the batch reactor, the effects of initial oxidation-reduction potential and nitrate concentration on denitrification were investigated. As the initial oxidation-reduction potential was decresed to -70 mV from ＋40 mV, the removal rate of nitrate was increased to 3.33 from 1.25 m9 NO$_3$$\^$-/-N/min under the experimental conditions. As the initial nitrate-N concentraion was increased to 200 mg/l, the removal rate of nitrate was proportional to the concentration of nitrate. When the concentration of nitrate-N was 400 mg/min, nitrite was detected, and when the initial nitrate-N concentration was reached at 1,000 mg/l, it took longer time for the complete nitrate removal. In order to decrease the initial oxidation-reduction potential and the nitrate-N concentration in the feed stream, the effluent was recycled to the influent stream in the packed-bed reactor. In the case of recycling, the initial oxidation-reduction potential was decreased to 30 mV from 150 mV, and the initial nitrate concentration could be decreased to 85 from 120 mg NO$_3$$\^$-/-N/l. As the result of recycling, the removal rate of nitrate was increased to 91.7% from 49.2%.