• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.11
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• pp.731-736
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• 2015

Rhodamine B (RhB) was utilized as a dye sensitizer for dye-sensitized solar cells (DSSCs) and its photovoltaic property was examined under the illumination of AM 1.5 G, $100mWcm^{-2}$. DSSCs based on RhB exhibited typical photovoltaic properties with an open-circuit voltage ($V_{OC}$) of 0.34 V, a short-circuit current ($J_{SC}$) of $1.55mA{\cdot}cm^{-2}$, a fill factor (FF) of 50%, and a conversion efficiency (PCE) of 0.26%. In order to further improve the photovoltaic properties of RhB-based DSSCs, the effect of (i) incorporating a strong electron-donating NCS unit into the RhB molecular backbone, (ii) combining a bis-negatively charged zinc complex anion ($Zn-dmit_2$, dmit=di-mercapto-dithiol-thione) with the amine cation of RhB, (iii) co-adsorbing RhB dyes with chenodeoxycholic acid (CDCA) molecules onto porous $TiO_2$ electrodes, was investigated and discussed.

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.297-304
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• 2013

Free-radical copolymerization of glycidyl methacrylate(GMA) and N-phthalimidoethyl acrylate(NPEA) were carried out at $60^{\circ}C$ in dimethylformamide(DMF) solution in the presence of benzoylperoxide(BPO) at low conversion. The polymers were characterized by IR and $^1H$-NMR. The compositions of the copolymer was analyzed by ultra violet(UV/Vis) spectrophotometry. The reactivity ratios of the monomer was determined by the application of Fineman-Ross(FR) and Kelen-T$\ddot{u}$d$\ddot{o}$s(KT) methods. The monomer reactivity ratios of the system and Alfrey-Price's resonance effect(Q) and polar effect(e) value for NIEA were determined as follow. The reactivity ratios of the monomer obtained from FR and KT are found to be $r_1$=0.87, $r_2$=0.98 and $r_1$=0.88, $r_2$=0.99 respectively. The Q and e values of poly(GMA-co-NPEM) calculated from $r_1$ and $r_2$ was Q= 1.31, e=0.75 respectively.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.391-396
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• 2015

To investigate the effect of the catalyst synthesis method on the oxidative dehydrogenation (ODH) of nbutenes, $BiFe_{0.65}MoP_{0.1}$ oxide catalysts were prepared with various synthesis methods such as co-precipitation, citric acid method, hydrothermal method, and surfactant templated method. The catalysts were characterized by X-ray Diffraction (XRD), $N_2$ sorption, and $NH_3/1$-butene-temperature programmed desorption ($NH_3/1$-butene-TPD) to correlate with catalytic activity in ODH reaction. Among the catalysts studied here, $BiFe_{0.65}MoP_{0.1}$ oxide catalyst prepared with co-precipitation method marked the highest activity showing 1-butene conversion, 79.5%, butadiene selectivity, 85.1% and yield, 67.7% after reaction for 14 h. From the result of $NH_3$-TPD, the catalytic activity is closely related to the acidity of the $BiFe_{0.65}MoP_{0.1}$-x oxide catalyst and acidity of the $BiFe_{0.65}MoP_{0.1}$ oxde catalyst prepared with co-precipitation method was higher than that of other catalysts. In addition, combined with the 1-butene TPD, the higher catalytic activity is closely related to the amount of weakly adsorbed intermediate (< $200^{\circ}C$) and the desorbing temperature of strongly adsorbed intermediates (> $200^{\circ}C$).

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.688-696
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• 2011

Hydrogen is one of the few long-term sustainable clean energy carriers, emitting only water as by-products during its combustion or oxidation. The use of fossil fuels to produce hydrogen makes large amount of carbon dioxide (>7 kg $CO_{2}$/kg $H_{2}$) during the reforming processes. Hydrogen production can be environmentally benign only if the energy and the resource to make hydrogen is sustainable and renewable. Biomass is an attractive alternative to fossil fuels for carbon dioxide because of the hydrogen can be produced by conversion of the biomass and the carbon dioxide formed during hydrogen production is consumed by biomass generation process. Hydrogen production using solar energy also attracts great attention because of the potential to use abundance natural energy and water.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.4250-4256
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• 2011

Mn catalyst promoted with Cu were prepared and tested for selective catalytic reduction of $NO_x$ with $NH_3$. Performance of each catalyst was investigated for $NO_x$ activity while changing temperature, space velocity, water content and $O_2$ concentration. Hydrogen conversion efficiency of catalyst was also measured in the $H_2$-TPR system. The inhibition effect of water on catalyst was investigated with the on-off control of water supply. High activity of Mn-Cu catalyst was observed for $160{\sim}260^{\circ}C$. It is found that increase of oxygen concentration acts as a promotor to the increase of catalyst activity but water content acts as a inhibitor.

• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.333-336
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• 2013

Experimental investigation to estimate the feasibility of fast selective catalytic reduction (SCR) or oxidation catalyst combined ammonia SCR system to abate NOx in low temperature condition ($150{\sim}250^{\circ}C$) is reported. Because the conversion of NO to $NO_2$ is pre-requisite of the fast SCR process, the effect of the amount of oxidation catalyst to NO conversion to $NO_2$ was tested. 37, 45 and 51% of conversion rates were obtained for the OCV of 563000, 375000 and 281000 h, respectively. $De-NO_x$ performance in the case of $NO_2/NO_x$ ratio of 45% showed the best result in all tested temperature conditions. Comparison of the fast SCR and standard SCR with the condition of $NO_2/NO_x$ ratio of 45%, $200{\sim}250^{\circ}C$ and space velocity of 10000~30000 h showed that the fast SCR does not show much difference according to the variance of space velocity. Also it was shown that using the fast SCR, the volume of SCR catalyst can be reduced less than half of the standard SCR condition by increasing space velocity without the loss of $De-NO_x$ performance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.2
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• pp.115-118
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• 2017

Highly photosensitive and wide bandgap amorphous silicon oxide (a-$SiO_x$:H) films were developed at low temperature ranges ($100{\sim}150^{\circ}C$) with employing plasma-enhanced chemical vapor deposition by optimizing $H_2/SiH_4$ gas ratio and $CO_2$ flow. Photosensitivity more than $10^5$ and wide bandgap (1.81~1.85 eV) properties were used for making the a-$SiO_x$:H thin film solar cells, which exhibited a high open circuit voltage of 0.987 V at the substrate temperature of $100^{\circ}C$. In addition, a power conversion efficiency of 6.87% for the cell could be improved up to 7.77% by employing a new n-type nc-$SiO_x$:H/ZnO:Al/Ag triple back-reflector that offers better short circuit currents in the thin film photovoltaic devices.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.2
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• pp.123-128
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• 2005

This paper presents an analysis of the permanent magnet overhang effect for the permanent magnetic actuator. Generally, the overhang is often used to increase the force density in permanent magnet machineries. The overhang is particularly profitable in reducing the volume after increasing the force density per volume when using the overhang effect of the permanent magnet. Therefore, the 3D Equivalent Magnetic Circuit Network Method (3D EMCN) has been used in this paper. According to the plunger position, the flux distribution per overhang length and the holding force are quantitatively compared. Furthermore, an appropriate length of the overhang has been proposed. To confirm the accuracy of the analysis method, the results of 2D FEM and 3D FEM are compared for the basic model.

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1329-1334
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• 2007

The electrochemical oxidation of cerium(III) was carried out using divided and undivided electrochemical cells in nitric acid medium. It was found that divided cell with Nafion 324 as the separator gave good conversion yield with high current efficiency compared to the undivided cell. The efficiency of the divided electrochemical cell was further optimized in terms of cell voltage, temperature, flow rate of solution recirculation, concentrations of Ce(III) and nitric acid. The better conditions for 1 M Ce(III) in 3 M nitric acid were found to be 2.5 V, 363 K and 100 mL/min recirculation flow rate based on the current efficiency under the experimental conditions investigated. The Ce(IV) oxidant produced was used as a mediator for the mineralization of phenol. The mineralization efficiency of the cerium mediated electrochemical oxidation was found rapid and higher compared to the direct electrochemical oxidation based on CO2 evolution under the same conditions.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.2 s.146
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• pp.258-267
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• 2006

The present piping modeling method requires detailed inputs from a designer to generate a piping model, and thus it takes much time for the designer to perform such task. Moreover, the piping model has no relation with that of hull structure. Thus, it is time-consuming and requires much effort if design changes arise. In this study, a method that generates quickly many pipes using a pipe tray and a conversion method that converts automatically the pipes into objects related with the hull structure are proposed. A piping modeling system based on the proposed methods is developed. The applicability of the developed system is demonstrated by applying it to the generation of the piping model of a deadweight 300,000ton VLCC(Very Large Crude oil Carrier). The results show that the developed system can quickly generate the piping model in relation with the hull structure.