• Title/Summary/Keyword: Matrix phase

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An Implementation of Inverse Filter for Sound Reproduction of Non-Minimum Phase System. (비최소 위상 시스템에서 음재생을 위한 역변환 필터의 구현)

  • 노경래;이상권
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.997-1002
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    • 2001
  • This paper describes an implementation of inverse filter using SVD in order to recover the input in multi-channel system. The matrix formulation in SISO system is extended to MIMO system. In time and frequency domain we investigates the inversion of minimum phase system and non-minimum phase system. To execute an effective inversion of non-minimum phase system, SVD is introduced. First of all we computes singular values of system matrix and then investigates the phase property of system. In case of overall system is non-minimum phase, system matrix has one (or more) very small singular value(s). The very small singular value(s) carries information about phase properties of system. Using this property, approximate inverse filter of overall system is founded. The numerical simulation shows potentials in use of the inverse filter.

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A Study on the Application of SVD to an Inverse Problem in a Cantilever Beam with a Non-minimum Phase (비최소 위상을 갖는 외팔보에서 SVD를 이용한 역변환 문제에 관한 연구)

  • 이상권;노경래;박진호
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.11 no.9
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    • pp.431-438
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    • 2001
  • This paper present experimental results of source identification for non-minimum phase system. Generally, a causal linear system may be described by matrix form. The inverse problem is considered as a matrix inversion. Direct inverse method can\`t be applied for a non-minimum phase system, the reason is that the system has ill-conditioning. Therefore, in this study to execute an effective inversion, SVD inverse technique is introduced. In a Non-minimum phase system, its system matrix may be singular or near-singular and has one more very small singular values. These very small singular values have information about a phase of the system and ill-conditioning. Using this property we could solve the ill-conditioned problem of the system and then verified it for the practical system(cantilever beam). The experimental results show that SVD inverse technique works well for non-minimum phase system.

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Magnetic Properties and Microstructures of Melt Spun Misch Metal-Ferroboron Alloys

  • Ko, K.Y.;Booth, J.G.;Al-Kanani, H.J.;Lee, H.Y.
    • Journal of Magnetics
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    • v.1 no.2
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    • pp.82-85
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    • 1996
  • Magnetic properties and microstructures of melt spun misch metal-ferroboron alloys were investigated. The major phase is the tetragonal (rare earth)$_2Fe_{14}B$ phase. Magnetic properties showed coercivity of 5.6 kOe, remanence of 7.85 kG, and so energy product 8.9 MGOe. Microsturctures in optimum properties showed that matrix was composed of Ce-rich phase while second phase La-rich-oxygen phase with less amount of Fe element than matrix, and triple junction with La-rich phase contrary to matrix.

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Efficiency of Gas-Phase Ion Formation in Matrix-Assisted Laser Desorption Ionization with 2,5-Dihydroxybenzoic Acid as Matrix

  • Park, Kyung Man;Ahn, Sung Hee;Bae, Yong Jin;Kim, Myung Soo
    • Bulletin of the Korean Chemical Society
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    • v.34 no.3
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    • pp.907-911
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    • 2013
  • Numbers of matrix- and analyte-derived ions and their sum in matrix-assisted laser desorption ionization (MALDI) of a peptide were measured using 2,5-dihydroxybenzoic acid (DHB) as matrix. As for MALDI with ${\alpha}$-cyano-4-hydroxy cinnamic acid as matrix, the sum was independent of the peptide concentration in the solid sample, or was the same as that of pure DHB. This suggested that the matrix ion was the primary ion and that the peptide ion was generated by matrix-to-peptide proton transfer. Experimental ionization efficiencies of $10^{-5}-10^{-4}$ for peptides and $10^{-8}-10^{-7}$ for matrices are far smaller than $10^{-3}-10^{-1}$ for peptides and $10^{-5}-10^{-3}$ for matrices speculated by Hillenkamp and Karas. Number of gas-phase ions generated by MALDI was unaffected by laser wavelength or pulse energy. This suggests that the main role of photo-absorption in MALDI is not in generating ions via a multi-photon process but in ablating materials in a solid sample to the gas phase.

Phase Separation of Matrix Glasses and Precipitation Characteristics of CuCl Nanocrystals in CuCl Doped Borosilicate Glasses for Nonlinear Optical Application (CuCl 미립자 분산 붕괴산염계 비선형 광학유리에서 매질유리의 상분리와 CuCl 미립자의 석출 특성)

  • 윤영권;한원택
    • Journal of the Korean Ceramic Society
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    • v.34 no.8
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    • pp.886-896
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    • 1997
  • To investigate an effect of phase separation on precipitation characteristics of CuCl nanocrystals in CuCl doped nonlinear optical glasses, borosilicate glass systems with 9 different compositions with ~2wt% of CuCl were selected and CuCl doped glasses were prepared by melting and precipitation method. Microstructural properties of the CuCl doped glasses were analyzed by optical absorption spectroscopy, acid elution test, TEM, and EDXS. While phase separation did not occur in Glass A~D, interconnected and droplet microstructures due to phase separation were found in Glass E, F and Glass G~I, respectively. In the particular composition of the matrix glasses in this study, the precipitation of the CuCl particles was observed in the phase separable glasses, not in phase non-separable glasses. The CuCl particles were precipitated in both silica-rich phase region and boronrich phase region of the glass matrix. In the case of 7.7Na2O-36.6B2O3-52.7SiO2(mole%) glass, the larger CuCl particles than those in the silica-rich phase region were observed in the boron-rich phase region.

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On the microstructure of pressureless sintered $TiC-TiB_2$ composite refractory (상압소성된 $TiC-TiB_2$ 복합내화재의 미세구조)

  • 심광보;김현기;오근호
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.7 no.4
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    • pp.632-639
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    • 1997
  • Relative density and microstructure of the pressureless sintered TiC-$TiB_2$ composite has been studied. The maximum sintered density was 95% and the critical amounts of sintering aids were 1 wt% Fe and 3 wt% Ni. It was found that TiC matrix phase inhibited effectively grain growth of the dispersed $TiB_2$ phase. The TEM investigation reveals that the Ni-rich precipitates were solidified from the liquid phase, confirmed by the presence of the waved and/or step phase boundaries. The precipitates also acts as the origin of the dislocation formation in the matrix phases.

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Fabrication and Mechanical Properties of Nanoquasicrystalline Phase Reinforced Ti-based Bulk Metallic Glass Matrix Composites (나노 준결정상으로 강화된 Ti계 벌크 비정질기지 복합재의 제조 및 기계적 특성 고찰)

  • Park, Jin-Man;Lim, Ka-Ram;Kim, Tae-Eung;Sohn, Sung-Woo;Kim, Do-Hyang
    • Journal of Korea Foundry Society
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    • v.28 no.6
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    • pp.261-267
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    • 2008
  • In-situ quasicrystalline icosahedral (I) phase reinforced Ti-based bulk metallic glass (BMG) matrix composites have been successfully fabricated by using two distinct thermal histories for BMG forming alloy. The BMG composite containing micron-scale Iphase has been introduced by controlling cooling rate during solidification, whereas nano-scale I-phase reinforced BMG composite has been produced by partial crystallization of BMG. For mechanical properties, micron-scale I-phase distributed BMG composite exhibited lower strength and plasticity compared to the monolithic BMG. On the other hand, nano-scale icosahedral phase embedded BMG composite showed enhanced strength and plasticity. These improved mechanical properties were attributed to the multiplication of shear bands and blocking of the shear band propagation in terms of isolation and homogeneous distribution of nanosize icosahdral phases in the glassy matrix, followed by stabilizing the mechanical and deformation instabilities.

Ferroelectric Characteristics of Pb-containing Perovskite-Pyrochlore Composites (Pb계 Perovskite-Pyrochlore 복합체의 강유전특성)

  • 조진우;손정호;조상희
    • Journal of the Korean Ceramic Society
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    • v.34 no.5
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    • pp.500-504
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    • 1997
  • Perovskite Pb0.7Ba0.3Zn1/3Nb2/3O3 substituted with 0.3 mole fraction for Pb-site in PbZn1/3Nb2/3O3 relaxor and pyrochlore Pb1.83Ba0.29Zn1.71Nb2/3O6.39 were mixed and dielectric characteristics of this composites were investigated. Percolation limit of perovskite phase, which was determined by microstructural observation in the composite as an isolation of perovskite phase from pyrochlore matrix, was 28.9-47.5 vol%. Ferroelectric phase transition below percolation limit depends on a parameter which affects the propagation of lattice vibration between isolated perovskite phase and pyrochlore matrix. Therefore, it is believed that ferroelectric lattice vibration of isolated perovskite phase could be transfered to pyrochlore matrix when the oxygen octahedra are linked in 3-dimension and highly polarizable Pb2+ ions are contained in both phases.

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Microstructure and Mechanical Properties of $Ti_3Al-Nb$ Alloys and TiB(Ti-25Al-11Nb) Metal Matrix Composite Fabricated by Spark Plasma Sintering Process (방전플라즈마 소결법으로 제작된 $Ti_3Al-Nb$ 합금 및 TiB/(Ti-25Al-11Nb) 금속기 복합재료의 미세조직과 기계적 성질)

  • 이성열
    • Journal of Advanced Marine Engineering and Technology
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    • v.27 no.1
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    • pp.124-133
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    • 2003
  • Ti-25Al-xNb (x=0, 3, 7, 11, 13 at. %) alloys and 18 vol. % TiB/(Ti-25Al-11Nb) metal matrix composite were fabricated by spark plasma sintering process at 900-120$0^{\circ}C$. Microstructural characteristics of the sintered bodies were identified by SEM, EDX analysis, X-ray diffraction, and differential scanning calorimeterric method. $Ti_3Al$ alloy was consisted of equiaxed $\alpha_2$ phase. $Ti_3Al-Nb$ alloys and the matix of TiB/(Ti-25Al-11Nb) metal matrix composite had the morphology that O phase was precipitated at the grain boundary of $\alpha_2$phase. Volume fraction of O phase and hardness were depended on the concentration of Nb in $Ti_3Al-Nb$ alloy, Rule of mixing could be applied to hardness and Young's modulus of 18 vol. % TiB/(Ti-25Al-11Nb) metal matrix composite.

The Study on the Cavitation Erosion Behavior of Hardfacing Alloys for Nuclear Power Plants (원전 밸브용 경면처리 합금의 캐비테이션 에로젼 (cavitation erosion) 거동에 관한 연구)

  • O, Yeong-Min;Kim, Yun-Gap;Kim, Seon-Jin
    • Korean Journal of Materials Research
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    • v.12 no.4
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    • pp.308-316
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    • 2002
  • The cavitation erosion behavior of wear-resistant hardfacing alloys such as Co-base Stellite 6, Fe-base Norem 02 and new Fe-base alloy were investigated up to 50 hours by using a 20kHz vibratory cavitation erosion test equipment. The crack, initiated easily at the interfaces between matrix and hard second phase, was repressed effectively in Stellite 6 because the matrix was hardened by phase transformation. For this reason, Stellite 6 showed an excellent cavitation erosion resistance compared to Norem 02. The phase transformation also occurred in Norem 02, but the increase of volume fraction of the interfaces caused the crack to be initiated frequently, thus resulting in a 1arge material loss. The matrix of NewAlloy was hardened effectively by vlongrightarrow$\alpha$' phase transformation and the volume fraction of the interfaces was very small compared to Norem 02. This caused the propagation of crack to the matrix to be repressed effectively. Therefore, NewAlloy showed a very excellent cavitation erosion resistance. It wasn't considered that the cavitation erosion resistance of NewAlloy was influenced the temperature of the bath filled with a distilled water up to $80^{\circ}C$.