• Journal of the Korean Chemical Society
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• v.38 no.12
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• pp.915-920
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• 1994

The Menschutkin type reactions of substituted (Z)-benzyl (X)-arenesulfonates with substituted(Y)-pyridines were studied by the electroconductometric method in acetonitrile at $35\circC$. Hammett $\rho$ values were calculated by the second order rate constants for the reaction of substituted (Z)-benzyl (X)-arenesulfonates with substituted (Y)-pyridines. The negative $\rho_Y$ values meant positive charge development on the nitrogen of pyridine at transition state owing to the charge development on the oxygen atom of benzenesulfonate. And the negative $\rho_Z$ values meant positive charge development on the benzylic carbon. Application of the multi-Hammett interaction,│$\rho_YZ$│ > │$\rho_XY$│ > │$\rho_ZX$│, the Menschutkin type reaction of substituted benzyl arenesulfonates with substituted pyridines was shown to be dissociative $S_N2$ mechanism.

• Journal of the Korean Chemical Society
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• v.46 no.3
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• pp.219-224
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• 2002

The oxidation reaction between 2,6-di-tert-butylphenol (DTBP) and oxygen adducted Co(III) complexes as a catalysis has been studied by UV-visible spectrophtometry. According to the results, main product is 2,6-di-tert-butylbenzoquinone(BQ) and the activity of the complexes is bigger in [Co(III)2(SMPD)2(Py)2]2O2 than in [Co(III)2(SPPD)2(Py)2]2O2. The rate constant is 4.55~2.12${\times}$10$-3}$s. It was found that the oxidation reaction is primary reac-tion or concentration of catalysis, O2 molecule and substance. The reasult is far from Arrhenius properties because acti-vationenergy is 10.38 kJ/mol.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.3
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• pp.227-233
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• 2014

Simulated waste-derived synthesis gas has been tested for hydrogen production through water-gas shift (WGS) reaction over supported Cu catalysts prepared by co-precipitation method. $CeO_2$, $ZrO_2$, MgO, and $Al_2O_3$ were employed as supports for WGS reaction in this study. $Cu-CeO_2$ catalyst exhibited excellent catalytic activity as well as 100% $CO_2$ selectivity for WGS in severe conditions ($GHSV=40,206h^{-1}$ and CO concentration = 38.0%). In addition, $Cu-CeO_2$ catalyst showed stable CO conversion for 20h without detectable catalyst deactivation. The high activity and stability of $Cu-CeO_2$ catalyst are correlated to its easier reducibility, high oxygen mobility/storage capacity of $CeO_2$.

• Journal of Energy Engineering
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• v.11 no.3
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• pp.247-253
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• 2002

Natural manganese ore was selected as main active component for a non-zinc desulfurization sorbent used in the gas clean-up process of the integrated gasification combined cycle (IGCC) because of excellent H$_2$S removal efficiency and economical aspect . In this study, the regeneration characteristics of sorbent after desulfurization reaction were determined in a thermobalance reactor and a fixed bed reactor in the temperature range of 350~55$0^{\circ}C$. The mixed gases of oxygen and nitrogen are used as the regeneration reaction gases for manganese sorbent. According to Mn-S-O phase diagram, the manganese sorbent has a low regeneration efficiency in medium temperature due to formation of MnSO$_4$ and the regeneration temperature must be over 85$0^{\circ}C$. To improve that problem, ammonia and steam was added in regeneration mixed gases. Effect of new regeneration method was determined by XRD and difference of desulfurization through multicycle tests.

• Journal of Environmental Science International
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• v.15 no.7
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• pp.669-676
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• 2006

PAHs are major pollutants that are widely distributed in soil and groundwater environment, so that may be regarded as carcinogens. We investigated the degradation kinetics of PAH in aqueous solution when low pressure UV energy and ultrasonic irradiation were applied. Phenanthrene and pyrene were used as model compounds. The degrees of degradation of these compounds with time were analyzed with a GC/MSD (SIM-mode). UV photolysis experiments showed that phenanthrene was reduced by 90 -67% at initial concentrations of 1 ppm to 8ppm whilst it decreased to 50% at 10 ppm. Under the same conditions pyrene was degraded up to about 75% at lower initial concentrations but the reduction efficiency dropped to a level of 34 to 29% at the higher concentrations above 8 ppm. The reaction orders for phenanthrene and pyrene were found to be zero-th and ca. -0.4th order, respectively, thus implying that the reported assumption of pseudo 1st order reaction for some PAHs would be no longer valid. PAH degradation was roughly proportional to the intensity of UV (number of lamps), exhibiting maximum 92.5% of the degradation efficiency. The solution pH was lowered to 4.4 from 6.4 during the experiments partially because the carbons decomposed by the energy reacted with oxygen radicals to produce carbon dioxides. Ultrasonic irradiation on phenanthrene solutions gave relatively poor results which matched to 50 to 70% of degradation efficiency even at 2 ppm of initial concentration. Phenanthrene was found to be degraded more efficiently than pyrene for the two energy sources. Ultrasound also followed the same reaction kinetics as UV energy on PAH degradation.

• Resources Recycling
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• v.13 no.6
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• pp.9-15
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• 2004

The optimum conditions were studied for the preparation of transparent iron oxide with the air oxidation of FeOOH. The FeOOH obtained by mixing NaOH and FeSO$_4$ solution in various conditions such as R(=2NaOH/FeSO$_4$), FeSO$_4$ concentration. reaction temperature and air flow rate. When the FeSO$_4$ increased gradually, the concentration of iron ion in the solution became high. So, particle size increased precipitating Fe$_3O_4$. Goethite dehydrate at about 200$^{\circ}C$ and ended the reaction at about 320$^{\circ}C$ forming hematite. The lower the reaction temperature was, the shorter the particle length of goethite and particle size decreased. When the flow rate of air as an oxidant increased, the amount of dissolved oxygen in the solution increased, which made oxidation rate increased. And then particle size of goethite decreased.

• Journal of the Korean Institute of Gas
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• v.4 no.2 s.10
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• pp.1-6
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• 2000

In this experiment, we made the plasma reactor which adhere needle electrode in order to treat safely an NOx which was included in the gas. Also we experimently investigated characteristics of equipment and inspected efficiency. As a reaction gas, by using mixture gas of $NO/N_2$ and $N_2/O_2$, we setted up initial NO concentration and gas flow rate was set at 2 ${\iota}$/min. As a reaction characteristics of NOx, when discharge input power was high, NO concentration decreased and when the oxygen concentration increased, the NO decomposition was easy and decomposition energy efficiency was high. Also in case that NO concentration increased, NO decomposition energy efficiency was high but decomposition rate was low. The characteristics of ozone, when discharge input power was high, ozone increased and when $NO/N_2$ concentration increased, the ozone decreased.

• Journal of Biomedical Engineering Research
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• v.34 no.4
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• pp.163-169
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• 2013

The purpose of this study was to verify exercise effect of horse riding exercise according to estimate basal physical fitness and activities of daily living(ADL) function in the aged. Participants were nineteen peoples who have no impediment of activity. They performed horse riding exercise using SRider(Neipplus, Co., Korea) at sixty minutes a day. Exercise has progressed three days a week for eight weeks. We measured trunk flexion, sit up, whole body reaction, leg strength and maximal oxygen uptake as basal physical fitness. Also three meter gait, single stance with eyes opened and single stance with eyes closed as ADL function were estimated once a month. The result of legs strength and whole body reaction showed the higher significantly than before the exercise. Moreover, the result of three meter walking ability only increased significantly among the ADL function. This means that horse riding exercise might be activated continuous muscular contraction with maintained tonus of muscle. We thought that continuous movement of horse riding could be lead to isometric muscle contraction in lower limbs. Our study found that horse riding exercise could improve lower strengths and muscle reaction for exercise effect. Also we suggested that horse riding exercise could be adapted to exercise methods that could provide rehabilitation and treatment enough for the aged or disabled person.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.63-68
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• 2018

This paper presents an integrated photochemical reaction system (i.e., an artificial leaf) that uses earth-abundant catalysts for artificial photosynthesis with a carbon dioxide ($CO_2$) fixation process. The performance of the system was investigated in terms of the energy capture and conversion capabilities. A wireless configuration was achieved by directly doping cobalt oxide as an oxygen-evolving catalyst for water splitting reaction on the illuminated surface of photovoltaic (PV) cell, as well as molybdenum disulfide ($MoS_2$) as an efficient catalyst for $CO_2$ reduction on the back substrate surfaces of the PV cell. The system produces hydrogen and carbon monoxide (CO) as sustainable fuels (i.e., synthesis gas) at around 4.5% efficiency, which implies more than 75% catalytic efficiency at the cathode. The process of solar-driven $CO_2$ conversion and water-splitting reaction is contained in one system, which is one step closer to the successful realization of artificial photosynthesis.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.6
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• pp.605-615
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• 2017

Efficient simultaneous reduction conditions for $NO_x$ and $NH_3$-slip was investigated in SCR (Selective Catalytic Reduction) process with load variation by applying dual catalysts (SCR catalyst, $NH_3$ decomposition catalyst) system. $N_2O$ formation characteristics were analyzed to look into possible undesirable reaction pathways. In the experiments of catalyst characteristics, various operational variables were tested for the combined catalytic system, such as $NH_3/NO_x$ ratio, temperature, oxygen concentration and $H_2O$. The reaction characteristics of $NO_x$, $NH_3$ and $N_2O$ were analyzed and optimal conditions could be evaluated for the combustion facility with varied load. In terms of $NO_x/NH_3$ simultaneous reduction and $N_2O$ formation suppression, optimal condition was considered NSR 1.2 and temperature $300^{\circ}C$. At this operational condition, $NO_x$ conversion was 98%, $NH_3$ reduction efficiency was 95%, generated $N_2O$ concentration 9.5 ppm with inlet $NO_x$ concentration of 100 ppm. In $NH_3-SCR$ process with $NH_3$ decomposition catalyst, $NO_x$ and $NH_3$ can be considered to be reduced simultaneously at limited conditions. The results of this study may be utilized as basic data at facilities requiring simultaneous $NO_x$ and $NH_3$ reduction for facilities with load variation.