• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.31 no.2 s.257
• /
• pp.188-194
• /
• 2007

New diesel engines equipped with common-rail injection systems and advanced engine management control allow drastic decreases in the production of particulate matters and nitrogen oxides with a significant advantage in terms of the fuel consumption and $CO_2$ emissions. Nevertheless, the contribution of exhaust gas after treatment in the ultra low emission vehicles conception has become unavoidable today. Recently the passive type DPF(Diesel Particulate Filter Trap) system for diesel passenger vehicle has been manufactured into mass production from a French automotive maker since the year of 2000. This passive DPF system fully relies on the catalytic effects from additives blended into the diesel fuel and additives injected into the DPF system. In this study, the effects of PM regeneration in the commercial diesel passenger vehicle with the passive type DPF system were investigated in chassis dynamometer CVS(constant volume sampler)-75 mode. As shown in this experimental results, the DPF regeneration was observed at temperature as low as $350^{\circ}C$. And the engine-controlled the DPF regeneration founded to be one of the most promising regeneration technologies. Moreover, the durability of this DPF system was evaluated with a season weather in terms of the differential pressure and exhaust gas temperature traces from a road test during the total mileage of 80,000km.

• Clean Technology
• /
• v.22 no.2
• /
• pp.82-88
• /
• 2016

The loss of activity by coke is an important cause of catalyst deactivation during industrial operation. In this study, hydrogen ratio of reaction condition, which has influenced on coke formation over Pt-Sn catalyst, and regeneration of catalysts activity by coke burning, Pt sintering of coke burning as coke contents, effects of coke formation and deactivation with different Sn contents were confirmed. Pt-Sn-K catalyst supported on θ-alumina and γ-alumina was prepared progressively. Activity of regenerated catalyst for propane dehydrogenation was compared with fresh catalyst by coke burning, after propane dehydrogenation was carried out with different hydrogen ratio at 620 ℃ on fresh catalyst. Regenerated catalyst’s physical characterization such as BET, coke analysis and XRD was investigated. Through catalytic activity test and characterization, Sn contents of catalyst and hydrogen ratio in feed stream could affect coke formation on catalyst surface. Excessive coke makes loss of activity and Pt sintering during air regeneration process.

• Journal of Pharmaceutical Investigation
• /
• v.26 no.4
• /
• pp.309-314
• /
• 1996

The purpose of this study is to explain the relationship between the pharmacological mechanism of levamisole and the cellular activity of cellular alkaline phosphatase (ALPase) in kidney cells. The results of our investigation were as follows. 1. Cellular ALPase activity in Macacus rhesus monkey kidney cells (MA 104 cells) and primary cultured rabbit kidney proximal tubular cells treated with levamisole was increased about two or three times than control. However, 50% of ALPase activity in cultured medium was inhibited by levamisole itself. 2. The proliferation of MA 104 and cultured rabbit kidney proximal tubular cells was linearly decreased in paralleled with increase of levamisole concentration $(50\;and\;500\;{mu}M)$ with MTT test. 3. In the heat stability tests, the inhibition of ALPase activity with and without levamisole at $56^{\circ}C$ in MA 104 cells showed different $IC_{50}$ values. 4. HPLC analysis of levamisole metabolites produced by cultured MA 104 cells suggested that the formation of a metabolite, that may be associated with its increase of cellular ALPase activity. Based on these results, we assumed that the increase of cellular ALPase activity by levamisole was evoked by modification of the ALPase catalytic sites.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.20 no.4
• /
• pp.491-496
• /
• 2017

The hydrogen($H_2$) is promising energy carrier of renewable energy in the microgrid system such as small village and military base due to its high energy density, pure emission and convenient transportation. $H_2$ can be generated by photocatalytic water splitting, gasification of biomass and water electrolysis driven by solar cell or wind turbine. Solid oxide electrolysis cells(SOECs) are the most efficient way to mass production due to high operating temperature improving the electrode kinetics and reducing the electrolyte resistance. The SOECs are consist of nickel-yttria stabilized zirconia(NiO-YSZ) fuel electrode / YSZ electrolyte / lanthanum strontium manganite-YSZ(LSM-YSZ) air electrode due to similarity to Solid Oxide Fuel Cells(SOFCs). The Ni-YSZ most widely used fuel electrode shows several problems at SOEC mode such as degradation of the fuel electrode because of Ni particle's redox reaction and agglomeration. Therefore Ni-YSZ need to be replaced to an alternative fuel electrode material. In this study, We studied on the Double perovskite $PrBrMnO_{5+{\delta}}$(PBMO) due to its high electric conductivity, catalytic activity and electrochemical stability. PBMO was impregnated into the scaffold electrolyte $La_{0.8}Sr_{0.2}Ga_{0.85}Mg_{0.15}O_{3-{\delta}}$(LSGM) to be synthesized at low temperature for avoiding secondary phase generated when it exposed to high temperature. The Half cell test was conducted at SOECs and SOFCs modes.

• Applied Chemistry for Engineering
• /
• v.19 no.3
• /
• pp.259-263
• /
• 2008

The catalytic activity of the used catalyst, $V_2O_5/TiO_2$, for MSW incinerators was investigated focusing on its regeneration. As the result of the experimental analysis, the NOx removal efficiency difference between the fresh catalyst and used catalyst is about 60% at $260^{\circ}C$ and 1, 2-dichlorobenzen (1, 2-DCB) removal efficiency difference is about 14% at $200^{\circ}C$, in honeycomb test. And the catalysts, both the fresh and used, were characterized by XRD, TGA, and ICP techniques in order to investigate the deactivation. On the basis of the results, it is found that the used catalyst is deactivated by ammonium-sulfates, heavy metals (Pb, As etc.), alkali metals (Ca), and phase transfer of $TiO_2$. Also calcination treatment under nitrogen and air condition was excellent than washing and calcination treatment.

• Applied Chemistry for Engineering
• /
• v.22 no.4
• /
• pp.400-404
• /
• 2011

The activity and stability of the metal filter material Pt coated on NOx and soot oxidation were examined. The catalytic reaction test for NOx and soot were also performed independently and simultaneously. As a result, it showed the NO to $NO_2$ shift reaction with 20% conversion, NOx decomposition (about 10%) and perfect soot oxidation on the material Pt coated proceeded. Onset temperature of soot oxidation shift to lower temperature (about $30^{\circ}C$) by generated $NO_2$. The material also was less affected by thermal shock than $Pt/Al_2O_3$ or $Pt/TiO_3$ catalysts due to its stability of surface structure.

• Clean Technology
• /
• v.24 no.2
• /
• pp.127-134
• /
• 2018

To reduce the environmental pollution by $NO_x$ from ship engine, International maritime organization (IMO) announced Tier III regulation, which is the emmision regulation of ship's exhaust gas in Emission control area (ECA). Selective catalytic reduction (SCR) process is the most commercial $De-NO_x$ system in order to meet the requirement of Tier III regulation. In generally, commercial ceramic honeycomb SCR catalyst has been installed in SCR reactor inside marine vessel engine. However, the ceramic honeycomb SCR catalyst has some serious issues such as low strength and easy destroution at high velocity of exhaust gas from the marine engine. For these reasons, we design to metallic structured catalyst in order to compensate the defects of the ceramic honeycomb catalyst for applying marine SCR system. Especially, metallic structured catalyst has many advantages such as robustness, compactness, lightness, and high thermal conductivity etc. In this study, in order to support catalyst on metal substrate, coating slurry is prepared by changing binder. we successfully fabricate the metallic structured catalyst with strong adhesion by coating, drying, and calcination process. And we carry out the SCR performance and durability such as sonication and dropping test for the prepared samples. The MFC01 shows above 95% of $NO_x$ conversion and much more robust and more stable compared to the commercial honeycomb catalyst. Based on the evaluation of characterization and performance test, we confirm that the proposed metallic structured catalyst in this study has high efficient and durability. Therefore, we suggest that the metallic structured catalyst may be a good alternative as a new type of SCR catalyst for marine SCR system.

• Applied Chemistry for Engineering
• /
• v.21 no.6
• /
• pp.697-701
• /
• 2010

We investigate the cell performance and characteristics of a direct formic acid fuel cell (DFAFC) using palladium (Pd) as a catalyst for anode. Pd is deposited on the electrolyte using the "direct paint" method. From a continuous three time-test of the polarization curve of the DFAFC, it is found that the catalytic activity of Pd and the cell performance of DFAFC steadily degrade as the tests are proceeded. This behavior may be due to the deactivation of Pd by formate (COOH) and hydroxyl (OH) groups, which are electrochemically dissociated from formic acid solution. Estimations of the degradation, followed by reactivation in activity of Pd catalyst and DFAFC cell performance are implemented by linear voltage sweep tests going in both positive and negative directions. When the maximum voltage of 1.0 V versus DHE is applied to the cell while a linear voltage sweep test going in negative directions, the activity of Pd catalyst and the DFAFC cell performance recover by the rehabilitation in activity of the deactivated Pd.

• Journal of Korean Society for Atmospheric Environment
• /
• v.23 no.5
• /
• pp.547-556
• /
• 2007

The release, sampling and analytical methods have been developed and tested for perfluorocarbons (PFCs) atmospheric tracers in order to gain insight into the atmospheric transport and dispersion over the urban conditions of Seoul, Korea. Although PFCs tracer experiments provide unique opportunities to test local and urban scale of transport and dispersion, no previous experiment with PFCs has been conducted in Korea. PMCH and PDCH were chosen as targeted tracers in our study due to their extreme low ambient concentrations and great sensitivities among various PFCs. For PFCs release system, a set of micro-metering pump, electronic balance, vaporizing furnace and high speed blower was constructed for precise and accurate release of tracers. The precision of released rate by this system was estimated to be 1%. Samplings of PFCs were carried out by fabricated portable air samplers with micro pumps and rotameters into glass tubes packed with 150 mg of Carboxen-569. The uncertainty of these sampling system was maintained below 14%. PMCH and PDCH were quantified in GC/ECD with preconditioned injection system to eliminate the interference compounds using traps and subsequent catalytic conversion system prior to column separation. Three intensive field test were undertaken during the springtime of 2002 to 2004 in eastern part of Seoul. Daily background samples were collected to characterize the background levels of PMCH and PDCH prior to their release. The observed background concentrations of PMCH ranged from 3.5 to 10.1 fL/L and varied randomly in location and time in this study. Its mean and standard variation of background concentration ($6.8{\pm}1.9\;fL/L$) are higher than those ($3.2{\sim}5.8\;fL/L$) of other historic tracer studies. Identified uncertainty for background PMCH was $1.7{\sim}2.0\;fL/L$ using this analytical system. Combined relative uncertainty in determining the tracer's concentrations was estimated as 17%. However, its background concentrations and uncertainty in concentration determination were found to be low and stable enough for tracer study.

• Journal of Korean Society of Environmental Engineers
• /
• v.32 no.10
• /
• pp.957-964
• /
• 2010

The deactivated catalyzed diesel particulate filter-trap (DPF) was remanufactured by ultrasonic wave treatment with various prepared solutions, followed by active component re-impregnation, and the emission control performance and surface properties of remanufactured DPF were studied at various remanufacturing conditions. The proper ultrasonic wave cleaning time at various prepared solutions and optimal re-impregnation amounts of active component for the best emission control performance of DPF were investigated and its performance tests were also carried out with various temperatures for the conversions of CO, THC (total hydrocarbon) and PM (particulate matter) by catalytic reaction test unit using bypass gas from the diesel engine dynamo system. It was found that the emission control performance of DPF remanufactured with the high-temperature air washing, ultrasonic wave cleaning at acid/base solutions and active component re-impregnation method was recovered to 95% level of its activity compared to that of the fresh DPF, which was caused by removing the deactivating materials from the surface of the DPF, through the analyses of performance test and their surface characterization by Optical microscope, EDX, ICP, TGA, and porosimeter.