• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.850-853
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• 1991

This paper suggests a triple laminated piezoelectric ceramic filter composed of three piezoelectric ceramic vibrators and two sheets of thin insulator, and an equivalent circuit of the filter and several expressions for the resonant frequency; voltage, current, and power gains under the various loads and frequencies; and phase differences between the input and the output voltages are introduced and simulated from its equivalent circuit when two outputs from the side vibrators are connected in series. Those expressions show that this filter has not only a filtering function but also an amplifying function.

• Journal of the Korean Ceramic Society
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• v.45 no.8
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• pp.464-471
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• 2008

The electrolyte separator for thermal battery should be easily handled and loaded a large amount of the molten salt. Ceramic fibers, especially fibrous commercial glass filters were used as an electrolyte separator and the lithium based molten salts were infiltrated into the ceramic filters. The pore structures of the ceramic filter and the melting properties of the lithium salts affected to the electrolyte loading and leakage. During the infiltration, ions of $Li^+$ and $F^-$ in the molten salts were reacted with the glass fiber and caused to be weaken the fiber strength.

• Journal of the Korean Ceramic Society
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• v.35 no.2
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• pp.201-207
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• 1998

A tube-type filter dam(or baffle with holes) for ferrous melt refining is applied to the tundish operation for molten steel having low carbon and ultra-low carbon. The changes in the total oxygen content insoluble aluminum content and the distribution of inclusion size in molten steel during tundish operation were in-vestigated at the pouring part strand and mold of tundish. Removal mechanism of inclusions is considered to be caused by buoyancy action of the filter dam better than filtration action and the size range of in-clusions filtrated by the filter dam was for 30-50$\mu\textrm{m}$. Decrease in deviation of inclusion content in molten steel was confirmed for appling the filter dam in comparison with using conventional dam and weir. Also the filter dam had the advantage of baffle with holes at lower part in the efficiency of inclusions removal.

• Journal of the Korean Ceramic Society
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• v.32 no.9
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• pp.989-994
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• 1995

Rigid porous carbon fiber composites with the uniform pore size distribution were prepared by vacuum forming from water slurries containing carbonized PAN fibers, a phenolic resin and ceramic binders. The composites were designed to use for highly efficient carbon fiber filters for particulate filtration and gas adsorption. As the as-received carbon fibers of 1mm in length were milled to an approximate average length of 300${\mu}{\textrm}{m}$, modulus of rupture (MOR) of the composite filter was increased from 1MPa to the value larger than 5 MPa. Modulus of rupture (MOR) for the composite filter fabricated using the milled carbon fiber was increased from 5 MPa to 10 MPa as the carbonization temperature of the PAN fiber was raised from 90$0^{\circ}C$ to 140$0^{\circ}C$. The air permeability and an average pore size of the composite filter were increased from 40 to 270cc/min.$\textrm{cm}^2$ and from 35 to 80${\mu}{\textrm}{m}$, respectively, as the apparent porosity increased from 80 to 95%. It was shown that the MOR of the carbon fiber composite filter was dependent primarily on the average length of carbon fiber, carbonization temperature and the type of bonding materials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.339-342
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• 1998

A high performance, high-dielectric stripline filter has been developed. The filter consists of planar resonators and its structure is made of high permittivity multilayer ceramic. The performance is distinctive with its attenuation pole. An equivalent lumped circuit is derived to explain the behavior of the attenuation pole quantitatively. A precise design procedure is also described.

• Journal of the Mineralogical Society of Korea
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• v.30 no.4
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• pp.173-178
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• 2017

In this study, the effect of sintering temperature and zero valent iron (ZVI) content on the physical properties of functional ceramic filter(alumina based materials) such as strength and porosity were investigated. The fabrication process of the functional ceramic filter were performed under various sintering temperature ($1150^{\circ}C$, $1250^{\circ}C$) and ZVI content (10, 20, 30, 50%) conditions. With increasing the sintering temperature and ZVI content, strength was increased but porosity was decreased. The physical properties for functional ceramic filter showed that the strength and porosity were obtained under ZVI content (50%) and sintering temperature ($1250^{\circ}C$) of 99.01 MPa and 34.5%, respectively.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.6
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• pp.60-66
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• 1992

This study describes a theoretical analysis for the wall temperature of ceramic filter trap and pressures of inlet and outlet channel in the filter trap. In this study, the maximum wall temperature through filter trap length with time during the regeneration period showed a tendency moving from forward to backward. The pressure change of filter trap increased at the initial combustion but decreased with the combustion to be activated. So the pressure difference between initial and end regeneration at the inlet channel showed about 2kPa. The thermal regeneration period of this filter trap in the theoretical analysis showed about 200seconds in which the wall temperature was similar to the case of initial condition and the pressure showed about 1 kPa.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.45-46
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• 2006

An ultrawide bandpass filter with sharp rejection and wider stopband is designed and implemented using multilayer ceramic configuration. The proposed filter is composed of a broadside coupled structure and a ring type filter with an embedded stripline stub. The measured results show that the fractional bandwidth and upper stopband of the proposed filter are 106 % and better than -30 dB, respectively. The insertion loss is less than 1 dB, and group delay is less than 0.3 ns in the passband. In addition, ring and broadside coupled gap structures are characterized and compared to the proposed structure.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.515-524
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• 2013

The program for dielectric ceramic waveguide filter was developed based on the direct coupled filter of ${\lambda}/2$ step impedance prototype. This developed program was called DWFD(Direct coupled Waveguide Filter Design). The filter was designed by 3-dimensional laminated type to reduce the size at the 1 GHz. S scattering matrix for this filter was calculated using the DWFD program. The width of inductive irises for laminated filter was computed by HFSS simulation tool. This waveguide filter was designed by 8 poles with bandwidth 25 MHz at the center frequency 881.5 MHz. By using a dielectric constant 35.4 and laminated type, the size of filter was reduced with width 50 mm and height 48 mm rapidly. We can see that the measured results agree well with the HFSS simulation result. Finally, this paper is shown that the design and implementation of waveguide filters can be presented by using DWFD program simply.

• Journal of the Korean Ceramic Society
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• v.43 no.4 s.287
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• pp.199-202
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• 2006

In this study, SiC whiskers were grown on a porous SiC diesel particulate filter for nanoparticle filtering. To grow the whiskers at the inner pore without closing the pores, we used chemical vapor infiltration with a solution source and a dilute. As the deposition time increased, the whiskers grew and formed a network structure. After 180 min of deposition, the mean diameter of the whiskers was 174 nm and the compressive strength was 58.4 MPa. The pores shrank from $10{\mu}m\;to\;0.4{\mu}m$ and, because the whiskers filed the inner pores, the gradient of permeability decreased as the deposition time increased. However, by using the network structure of whiskers deposited for 120 min and 180 min, we obtained a diesel particulate filter with pores of $0.98{\mu}m\;and\;0.4{\mu}m$, respectively. Furthermore, the filter shows better permeability than a porous body with pores of $1{\mu}m$. In short, by filtering the nanoparticulate materials, the network structure of whiskers improves the strength, reduces the pore size and minimizes the permeability drop.