• Membrane Journal
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• v.8 no.3
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• pp.117-129
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• 1998

The atmospheric pollution by diesel emission is mainly attributed to particulate matters and NO$_x$. Their regulation limits have become tighter. This paper reviews the characteristics and the fabrication method of the diesd particulate filter(DPF) which is used to control the particulate matters of diesel emission. First the constituent of particulate matters and the regulation standard are discussed and then the state of the art post-treatment system is reviewed. The materials, the fabrication method and the control of thermal expansion of the ceramic honeycomb filter, which is widely used as the DPF, are also reviewed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.10
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• pp.1060-1070
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• 2003

The frequency selective surface for use in Ka/Ku band parabolic antenna of domestic satellite communications is proposed. The frequency selective surface structure consists of the infinite periodic arrays of the triple square loop slot element with narrow width on the honeycomb structure of multi-layered dielectric. The frequency selective surface is fabricated and measured. The good agreement is obtained between theory and experiment. It is demonstrated that the frequency selective surface passes 14/12 GHz band wave while reflecting 30/20 GHz band wave as required.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.928-935
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• 2010

A bag filter system was partially burnt down during a trial run of waste wood incineration boiler. This brought about unburned hydrocarbon which caused a rapid deactivation of low temperature SCR catalyst set up in two stage after the bag filter. The deactivated catalyst was investigated in order to trace the origin by several characterization methods such as XRD, EDX, BET, TGA, SEM. The deactivated catalyst was regenerated by different methods such as acid washing, water washing in ultrasonication, and calcination treatment under air condition. It is found the calcination treatment under air condition at $450^{\circ}C$ for 2 hours to be the best regeneration method. The catalytic activity was measured in the form of 2 cm ${\times}$ 2 cm ${\times}$ 10 cm (catalyst weight 10 g) honeycomb type. A deNOx efficiency of the regenerated catalyst showed 100% at $180^{\circ}C$ which is the same level of fresh one.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.5
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• pp.556-565
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• 2016

As a result of the enforced control of emission, many devices, including the diesel particulate filter, have been installed in diesel cars to reduce the emission of particulate matters. In this study, a car fire case has been investigated and analyzed. A car fire broke out after the vehicle traveled a distance of 1.4 km from a car service center. The car was provided with DPF cleaning when the DPF warning light came on. After being dismantled in the engine room, the car's engine and gearbox were investigated. The findings showed that the rear part of the DPF metal case was melted and punctured, while the honeycomb filter of the DPF was damaged. The car fire was caused by an overheated DPF associated with inaccurate maintenance practice. Therefore, the responsibility of the fire rested on the car service center that performed the DPF cleaning.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.4
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• pp.133-138
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• 2009

The continued rise in the number of automobiles on the roads is prompting air pollution to emerge as a serious problem due to the harmful exhaust gas emissions throughout the world. Specifically, based on the exhaust gas regulation in North America represented by PZEV, the regulation on evaporative emission, which originates from the intake manifold system when the engine is stopped, is substantially being intensified. And the technology that can meet and satisfy these regulations has been needed. This study aimed to analyze and evaluate the butane working capacity (BWC) of HC adsorption filter according to the shape of it, which was developed to reduce evaporative emission, and the effect of HC adsorption filter on the engine performance. As a results, HC adsorption filter of the plate type, which was improved compared to that of the corrugated type and also became thinner, indicates higher absorption performance compared to the corrugated one. The absorption performance of the honeycomb type, derived from improving the shape of plate type, is 33.5% higher than that of the corrugated type. However, there was no significant difference in engine performance in all shapes.

• Journal of the Korean Ceramic Society
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• v.45 no.2
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• pp.132-137
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• 2008

The main purpose of this study is enhancing the filtering efficiency, performance and durability of filter by growing SiC whiskers on cordierite honeycomb substrate. The experiment was performed by Chemical Vapor Infiltration (CVI) in order to control pore morphology of substrate. Increasing the mechanical strength of porous substrate is one of important issues. The formation of "networking structure" in the pore of porous substrate increased mechanical strength. The high pressure gas injection to the specimen showed that a little of whiskers were separated from substrate but additional film coating enhanced the stability of whisker at high pressure gas injection. Particle trap test was performed. More nano-particle was trapped by whisker growth at the pore of substrate. Therefore it is expected that the porous cordierite which deposited the SiC whisker will be the promising material for the application as filter trapping the nano-particles.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.1
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• pp.30-35
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• 2017

In this study, we measured the natural frequencies of aluminum honeycomb sandwich beams using digital image correlation technique. The vibration images were captured using two high speed digital cameras and the images were converted to displacements by the digital image correlation technique. Displacement data in time domain were tranformed to frequency domain data by fast Fourier transform software. To reduce noise invoked by random exitation, a spectrum averaging technique and Savitsky-Golay digital filter were adopted. A conventional vibration measurement using an accelerometer and a finite element analysis were performed to compare the results by high speed digital camera measurement method. In conclusion, new method using high speed digital cameras and digital image correlation technique can measure the vibration of beam structures and can be applied to bio-structures where sensors cannot be attached.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.363-368
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• 2008

Nitrogen oxides (NO, $NO_2$ and $N_2O$) have been controlled effectively by the SCR catalysts coated on monolith or honeycomb in commercial sites with ammonia as reductant at high temperature range $300{\sim}400^{\circ}C$. However, the catalytic filter has much merit on the point of controlling the particles and nitrogen oxides simultaneously. It will be more advanced-system if the catalytic working temperature is reduced to the normal filtration temperature of under $200^{\circ}C$. This study has focus on the development of the catalytic filter working at the low temperature. So the additive effect of the components such as Pt and Mn (which are known the catalytic component of $V_2O_5/TiO_2$ was investigated. The $V_2O_5-WO_3$ catalytic filter exhibited high activity and selectivity at $250{\sim}320^{\circ}C$ showing more than 95% NO conversion for the treatment of 600 ppm NO at face velocity 2 cm/s. The Pt-$V_2O_5-WO_3$ catalytic filter shifted the optimum working temperature towards the lower temperature ($170{\sim}200^{\circ}C$). And NO conversion was 100% and higher than that of $V_2O_5-WO_3$ catalyst at $250{\sim}320^{\circ}C$. The $MnO_X-V_2O_5-WO_3$ catalytic filter showed the wide temperature range of $220{\sim}330^{\circ}C$ for more than 95% NO conversion. This is a remarkable advantage when considered the $MnO_X$ catalytic filter presents the maximum activity at $150{\sim}250^{\circ}C$ and $V_2O_5-WO_3$ catalytic filter shows the maximum activity at $250{\sim}320^{\circ}C$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5384-5391
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• 2011

The computational fluid dynamics was analyzed for the pressure distribution, stream velocity distribution, stream line field, retention time and temperature distribution which are applied to the catalyst layer in the RCO reactor to derive the optimum operating condition of the heat condensing type catalytic oxidation (RCO) reactor. The results from the computational analysis revealed that the pressure loss due to the ceramic honeycomb in the catalytic bed of the reactor which is operating currently is not significant and the stream velocity (1.8~2.7 m/s) after the ceramic filter is working in stability without big channeling. To improve the stream velocity distribution of the air stream, it is necessary to extension of the connecting range between the plenum and catalytic bed inside the facility. However, the method of attaching the air stream guide vane or the perforated plate inside the reactor was not so effective.