• Title/Summary/Keyword: filter materials

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Fabrication and Characterization of Tunable Bandpass Filter using BST Thin Films

  • Kim, Il-Doo;Kim, Duk-Su;Park, Kyu-Sung;Kim, Ho-Gi
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07b
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    • pp.581-584
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    • 2002
  • In this work, a CPW resonator was designed and fabricated to investigate the basic microwave properties, such as effective dielectric constant, of BST thin films. Their properties were used as basic data to simulate and design CPW tunable bandpass filter. We also report on gold/$Ba_{0.5}Sr_{0.5}TiO_3$(BST) ferroelectric thin film C-band tunable bandpass filters(BPFs) designed and fabricated on magnesium oxide substrates using CPW structure. The 2 pole filter was designed for a center frequency of 5.88 GHz with a bandwidth of 9 %. The BST based CPW filter offers a high sensitivity parameter as well as a low loss parameter. The tuning range for the bandpass filter with CPW structure was determined to be 170 MHz.

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Optimization of Energy Modulation Filter for Dual Energy CBCT Using Geant4 Monte-Carlo Simulation

  • Ju, Eun Bin;Ahn, So Hyun;Choi, Sang Gyu;Lee, Rena
    • Progress in Medical Physics
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    • v.27 no.3
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    • pp.125-130
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    • 2016
  • Dual energy computed tomography (DECT) is used to classify two materials and quantify the mass density of each material in the human body. An energy modulation filter based DECT could acquire two images, which are generated by the low- and high-energy photon spectra, in one scan, with one tube and detector. In the case of DECT using the energy modulation filter, the filter should perform the optimization process for the type of materials and thicknesses for generating two photon spectra. In this study, Geant4 Monte-Carlo simulation toolkit was used to execute the optimization process for determining the property of the energy modulation filter. In the process, various materials used for the energy modulation filter are copper (Cu, $8.96g/cm^3$), niobium (Nb, $8.57g/cm^3$), stannum (Sn, $7.31g/cm^3$), gold (Au, $19.32g/cm^3$), and lead (Pb, $11.34g/cm^3$). The thickness of the modulation filter varied from 0.1 mm to 1.0 mm. To evaluate the overlap region of the low- and high-energy spectrum, Geant4 Monte-Carlo simulation is used. The variation of the photon flux and the mean energy of photon spectrum that passes through the energy modulation filter are evaluated. In the primary photon spectrum of 80 kVp, the optimal modulation filter is a 0.1 mm lead filter that can acquire the same mean energy of 140 kVp photon spectrum. The lead filter of 0.1 mm based dual energy CBCT is required to increase the tube current 4.37 times than the original tube current owing to the 77.1% attenuation in the filter.

Determination of Loss Volume according to Hydraulic Pressure in Filter Materials (필터재의 수압에 따른 유실량 측정)

  • In, Hyun-Sik;Song, Chang-Seob;Lim, Sung-Yoon
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2002.10a
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    • pp.337-340
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    • 2002
  • The purpose of this study is to evaluate the loss volume of base soil materials with the grain size range of filter materials for agricultural reservoir. The test results show that the loss volume is increased with the hydraulic pressure, and the amount of loss volume for same sample is different with the filter range.

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Development of Miniature Quad SAW Filter Bank based on PCB Substrate

  • Lee, Young-Jin;Kim, Chang-Il;Paik, Jong-Hoo
    • Transactions on Electrical and Electronic Materials
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    • v.9 no.1
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    • pp.33-37
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    • 2008
  • This paper describes the development of a new $5.0{\times}3.2mm$ SAW filter bank which is consist of 12 L, C matching components and 4 SAW bare chips on PCB substrate with CSP technology. We improved the manufacturing cost by removing the ceramic package through direct flip bonding of $LiTaO_3$ SAW bare chip on PCB board after mounting L, C passive element on PCB board. After that we realized the hermitic sealing by laminating the epoxy film. To confirm the confidentiality and durability of the above method, we have obtained the optimum flip bonding & film laminating condition, and figured out material property and structure to secure the durability & moisture proof of PCB board. The newly developed super mini $5.0{\times}3.2mm$ filter bank shows the superior features than those of existing products in confidence, electrical, mechanical characters.

Implementation of V-Band Filter using MCM-D Technology (MCM-D 기판 공정 기술을 이용한 V-Band Filter 구현)

  • Yoo, Chan-Sei;Song, Sang-Sub;Park, Jong-Chul;Seo, Kwang-Seok
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.169-170
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    • 2006
  • A band pass filter for the V-band application with unique circuit and structure was designed and implemented using 2-metals, 3-BCB layers. In the mean while the effective electrical conductivity of metal layer was extracted and its value was $4{\times}10^7S/m$. The insertion loss of band pass filter at 60 GHz was 3.0 dB and group delay was below 0.1 ns.

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Ceramic Diesel Particulate Filter Structure with Inclined Gas Paths

  • Hwang, Yeon;Kang, Dae-Sik;Choi, Hyoung-Gwon;Lee, Choong-Hoon
    • Journal of the Korean Ceramic Society
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    • v.49 no.3
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    • pp.226-230
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    • 2012
  • This paper presents a novel structure for a diesel particulate filter (DPF) with inclined gas paths, which was designed so that the gas paths offered a fluent flow of exhaust gases, and particulate matter (PM) was collected at pores formed in the body. The alumina porous filter was prepared by a conventional sintering process at $1200^{\circ}C$ for 2 h. Straight gas paths with $30^{\circ}$ of inclination from the gas flow direction were formed in the filter body. It is shown that this filter structure worked as a PM filter, in which 90.2% of soot filtration efficiency and 59.6 mbar of pressure drop were achieved.

Electronic Spin Filter via Spin Superlattice

  • Han, Jae-Ho;Lee, H.W.;You, Chun-Yeol
    • Journal of Magnetics
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    • v.12 no.2
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    • pp.77-80
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    • 2007
  • Recently there was a proposal for a spin filter by using the spin superlattice structure. In a certain energy range, the proposed structure exhibits a high spin filtering efficiency close to 100%. Unfortunately such energy range turns out to be narrow. In this paper, we report a method to widen the energy range by using an analogy to optical anti-reflection coating. In optics, it is well known that a stack of alternating layers of two dielectric materials can function as a highly transmissive or reflective filter for wide range of wavelength. Since electrons also have wave character as light, it would be possible to make an electronic analog of an optical filter. We demonstrate that alternating layers of two materials with different g-factors can function as a spin filter that allows electrons to be transmitted only when their spins point towards a certain particular direction. This spin-superlattice-based spin filter operates in wide energy ranges, curing the problem in the previous proposal.

Porous Photocatalytic Concrete Filter Manufacturing and Efficiency Evaluation for NOx Reduction (NOx 저감을 위한 다공성 광촉매 콘크리트 필터 제조 및 효율평가)

  • Kim, Jong Kyu
    • Korean Journal of Materials Research
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    • v.32 no.4
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    • pp.223-229
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    • 2022
  • A porous photocatalyst concrete filter was successfully produced to remove NOx, by mixing TiO2 photocatalyst with lightweight aerated concrete. Ultra Fine Bubbles were used to form continuous pores inside the porous photocatalytic concrete filter, which was mixed via a bubble generation experiment. The optimal mixing condition was determined to be with 4 % of the bubble generation agent B. NO removal specimens were prepared for various photocatalytic loading conditions, and the specimen containing 3 % P-25 removed NO at a concentration of 1.03 µmol in 1 h. The NO removal rate of the porous photocatalytic concrete filter prepared in this study was 10.99 %. This photocatalytic filter performance was more than 9 times the amount of NO removed by a general photocatalytic filter. The porous photocatalyst concrete filter for removing NOx developed in this study can be applied to various construction sites and the air quality can be solved by reducing NOx contributing to the formation of fine particles.

Optimal filter materials for protist quantification via droplet digital PCR

  • Juhee Min;Kwang Young Kim
    • ALGAE
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    • v.39 no.1
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    • pp.51-56
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    • 2024
  • The use of droplet digital polymerase chain reaction (ddPCR) has greatly improved the quantification of harmful protists, outperforming traditional methods like quantitative PCR. Notably, ddPCR provides enhanced consistency and reproducibility at it resists PCR inhibitors commonly found in environmental DNA samples. This study aimed to determine the most effective filter material for ddPCR protocols by assessing the reproducibility of species-specific gene copy numbers and filtration time across six filter types: cellulose acetate (CA), mixed cellulose ester (MCE), nylon (NY), polycarbonate (PC), polyethersulfone (PES), and polyvinylidene fluoride (PVDF). The study used two species of Chattonella marina complexes as a case study. Filtration rates were slower for NY, PC, and PVDF filters. Moreover, MCE, NY, PES, and PVDF yielded lower DNA amounts than other filters. Importantly, the CA filter exhibited the lowest variance (38-39%) and the highest determination coefficients (R2 = 0.92-0.96), indicating superior performance. These findings suggest that the CA filter is the most suitable for ddPCR quantification of marine protists, offering quick filtration and reliable reproducibility.