• Title/Summary/Keyword: Spectrum broadening

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Development of PC Based Signal Postprocessing System in MR Spectroscopy: Normal Brain Spectrum in 1.5T MR Spectroscopy (PC를 이용한 자기공명분광 신호처리분석 시스템 개발: 1.5T MR Spectroscopy에서의 정상인 뇌 분광 신호)

  • 백문영;강원석;이현용;신운재;은충기
    • Investigative Magnetic Resonance Imaging
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    • v.4 no.2
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    • pp.128-135
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    • 2000
  • Purpose : The aim of this study is to develope the Magnetic Resonance Spectroscopy(MRS) data processing S/W which plays an important role as a diagnostic tool in clinical field. Materials and methods : Post-processing software of MRS based on graphical user interface(GUI) under windows operating system of personal computer(PC) was developed using MATLAB(Mathwork, U.S.A.). This tool contains many functions to increase the quality of spectrum data such as DC correction, zero filling, line broadening, Gauss-Lorentzian filtering, phase correction, etc. And we obtained the normal human brain $^1H$ MRS data from parietal white matter, basal ganglia and occipital grey matter region using 1.5T Gyroscan ACS-NT R6 (philips, Amsterdam, Netherland) MRS package. The analysis of the MRS peaks were performed by obtaining the ratio of peak area. Results : The peak ratios of NAA/Cr, Cho/Cr, MI/Cr for the different MRS machines have a little different values. But these peak ratios were not significantly different between different echo time MRS peak ratios in the same machine (p<0.05). Conclusion : MRS post-processing S/W based on GUI using PC was developed and applied to the analysis of normal human brain $^1H$ MRS. This independent MRS processing job increases the performance and throughput of patient scan of main console. Finally, we suggest that the database for normal in-yivo human MRS data should be obtained before clinical applications.

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Formant-broadened CMS Using the Log-spectrum Transformed from the Cepstrum (켑스트럼으로부터 변환된 로그 스펙트럼을 이용한 포먼트 평활화 켑스트럴 평균 차감법)

  • 김유진;정혜경;정재호
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.4
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    • pp.361-373
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    • 2002
  • In this paper, we propose a channel normalization method to improve the performance of CMS (cepstral mean subtraction) which is widely adopted to normalize a channel variation for speech and speaker recognition. CMS which estimates the channel effects by averaging long-term cepstrum has a weak point that the estimated channel is biased by the formants of voiced speech which include a useful speech information. The proposed Formant-broadened Cepstral Mean Subtraction (FBCMS) is based on the facts that the formants can be found easily in log spectrum which is transformed from the cepstrum by fourier transform and the formants correspond to the dominant poles of all-pole model which is usually modeled vocal tract. The FBCMS evaluates only poles to be broadened from the log spectrum without polynomial factorization and makes a formant-broadened cepstrum by broadening the bandwidths of formant poles. We can estimate the channel cepstrum effectively by averaging formant-broadened cepstral coefficients. We performed the experiments to compare FBCMS with CMS, PFCMS using 4 simulated telephone channels. In the experiment of channel estimation, we evaluated the distance cepstrum of real channel from the cepstrum of estimated channel and found that we were able to get the mean cepstrum closer to the channel cepstrum due to an softening the bias of mean cepstrum to speech. In the experiment of text-independent speaker identification, we showed the result that the proposed method was superior than the conventional CMS and comparable to the pole-filtered CMS. Consequently, we showed the proposed method was efficiently able to normalize the channel variation based on the conventional CMS.

Interaction of Cytochrome c and Cytochrome c Oxidase Studied by Spin-Label EPR and Site-Directed Mutagenesis

  • Park, Hee-Young;Chun, Sun-Bum;Han, Sang-Hwa;Lee, Kwang-Soon;Kim, Kyung-Hoon
    • BMB Reports
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    • v.30 no.6
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    • pp.397-402
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    • 1997
  • A thiol-specific spin label was attached to cysteine-102 of yeast cytochrome c and electron paramagnetic resonance (EPR) spectra were measured as a function of added cytochrome c oxidase concentration. The intensity decreased due to line broadening as cytochrome c formed a complex with cytochrome c oxidase and reached a minimum when the ratio of cytochrome c to cytochrome c oxidase became one. Replacement of either Lys-72 or Lys-87 of cytochrome c by Glu did not result in a significant change in binding affinity. Interestingly the K72E mutant, unlike K87E, had a much lower rate of electron transfer than the wild type. These results indicate that many positively charged residues as a group participate in complex formation but Lys-72 might be important for cytochrome c to be locked in an orientation for an efficient electron transfer. A stoichiometry of 1 was also confirmed by optical absorption of the cytochrome c-cytochrome c oxidase complex which had been run through a gel chromatography cloumn to remove unbound cytochrome c. The EPR spectrum of this 1:1 complex, however, was a mixture of two components. This explains a biphasic kinetics for a single binding site on cytochrome c oxidase without invoking conformational transition.

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A Study on Woman Growth-Narrative and Modes of Expression Graphic Novel 『Habibi』 (그래픽 노블 『하비비』의 표현양식과 여성 성장 서사 연구)

  • Lee, Young-Soo
    • Cartoon and Animation Studies
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    • s.43
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    • pp.231-254
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    • 2016
  • The graphic novel is seemed different from comics in two aspects, visual expression and narrative value. However, they are ambiguous standards, so it needs to research each works of graphic novel deeper. Then this paper studied both of visual expression and narrative in Craig Thompson's "Habibi" that has been recognized a fine graphic novel. As the research about how the modes of expression that an American author choose on purpose to represent an arab female are related with narrative, it will get the point of narrative strategy that graphic novel can have potentially. So It studied new modes of expression as focusing on imagination of arab letters and woman growth-narrative by using Gayle Rubin's 'traffic in women' theory, and how it was related with modes of expression in graphic novel. This paper will be helpful for broadening spectrum of expression in graphic novel as comics media having own narrative form and studying graphic narrative potential.

Modification of Rubbers through Chemical Reactions including Controlled/"living" Radical Polymerization Techniques (리빙라디칼 중합법을 포함한 화학적 방법에 의한 고무의 개질)

  • Joo, Sang-Il;Cho, Hyun-Chul;Lee, Seong-Hoon;Hong, Sung-Chul
    • Elastomers and Composites
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    • v.44 no.2
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    • pp.122-133
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    • 2009
  • Rubbers, such as natural rubber, polybutadiene, styrene-butadiene rubber, nitrile-butadiene rubber, chlorinated rubber and EPDM, have been continuously improved in response to a heavy demand and a new property requirement from industry. One of the best ways to realize the improvement is the modification of rubbers through chemical reactions, which produce materials with novel properties. In this review, chemical modification reactions of rubbers that contain carbon-carbon double bond units either in their main backbone or as a side group were briefly summarized. The chemical reactions introduce functional groups or functional polymer chains to polymer backbone, which transform a classical rubber to a highly functional material. Especially, we focused on a controlled/"living" radical polymerization techniques, with which a revolutionary broadening of the spectrum of the materials with well defined molecular weight, molecular weight distribution, chain end-functionality and architectures become possible.

Crystallographic and Mossbauer studies of $Ni_{0.65}Zn_{0.35}Cu_{0.1}Fe_{1.9}O_4$ ($Ni_{0.65}Zn_{0.35}Cu_{0.1}Fe_{1.9}O_4$의 결정학적 및 Mossbauer 효과 연구)

  • 김우철;이승화;홍성렬;옥항남;김철성
    • Journal of the Korean Magnetics Society
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    • v.8 no.3
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    • pp.118-124
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    • 1998
  • $Ni_{0.65}Zn_{0.35}Cu_{0.1}Fe{1.9}O_4$ has been studied with Mossbauer spectroscopy and X-ray diffraction. The crystal structure is found to be a cubic spinel with the lattice constant $a_0=8.390{\AA}$. Mossbauer spectra of $Ni_{0.65}Zn_{0.35}Cu_{0.1}Fe{1.9}O_4$ has been taken at various temperatures ranging from 12 K to 705 K. The isomer shift indicates that iron ions are ferric at tetrahedral [A] and octahedral sites [B], respectively. The Neel temperature is determined to be $T_N=705\;K$. As the temperature increases toward $T_N$ a systematic line broadening effect in the Mossbauer spectrum is observed and interpreted to originate from different temperature dependencies of the magnetic hyperfine fields at various iron sites. The quadrupole splitting just on $T_N$ is 0.41 mm/s whereas the quadrupole shift below $T_N$ vanishes. This implies that the orientation of the magnetic hyperfine field with respect to be principal axes of the electric field gradient is random.

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Calculation of Gamma-ray Energy Spectrum for Spherical BGO Scintillation Detector (구형 BGO 섬광 검출기에 대한 감마선 에너지 스펙트럼 계산)

  • Doh, Sih-Hong;Kim, Jong-Il;Park, Hung-Ki;Chu, Min-Cheal;Jeong, Jung-Hyun;Kim, Gi-Dong;Lee, Dae-Won
    • Journal of Sensor Science and Technology
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    • v.4 no.4
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    • pp.1-9
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    • 1995
  • The ${\gamma}$-ray deposition spectra were calculated by Monte Calro method to obtain the scintillation characteristics of the ${\gamma}$-ray for BGO scintillation detector with the spherical shape of 1.25 cm radius. The code used in calculating the ${\gamma}$-ray deposition spectra was made for personal computer with qbasic language. Also the ${\gamma}$-ray energy spectra of $^{22}Na$, $^{137}Cs$ and $^{207}Bi$ were measured with the detector. The energy dependent resolution below 2000 keV for the detector was determined by estimating the standard deviation of the photopeak fitted with gaussian function, and $X^{2}$ fitting using Nardi's empirical formula. The measured spectra of $^{22}Na$ and $^{137}Cs$ were compared with the broadened spectra which were obtained by broadening the calculated ${\gamma}$-ray deposition spectra with the energy dependent resolution. The absolute efficiency and the intrinsic peak efficiency of the detector were obtained by calculating the ${\gamma}$-ray deposition spectrum with the code.

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Investigation of Various Radiation Proton Energy Effect on n, p Type Silicon by Positron Annihilation Method (양전자 소멸 측정법으로 양성자 조사에너지 변화에 대한 n, p형 실리콘 구조 특성)

  • Lee, Chong Yong
    • Journal of the Korean Vacuum Society
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    • v.22 no.6
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    • pp.341-347
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    • 2013
  • The n-type and p-type silicon samples were exposed by 40.0, 3.98 MeV proton beams ranging between 0 to $20.0{\times}10^{13}protons/cm^2$. Coincidence Doppler Broadening Positron Annihilation Spectroscopy (CDBPAS) were applied to study of defect characteristics of p type and n type silicon samples. In this investigation the numerical analysis of the spectra was employed to the determination of the shape parameter, S, defined as the ratio between the amount of counts in a central portion of the gamma spectrum and the total counts of whole gamma spectrum. The S-parameter values strongly depend on the irradiated proton beam that indicated the defects generate more, rather than the energy intensity. 40 MeV irradiated proton beam in the n-type silicon at $20.0{\times}10^{13}protons/cm^2$ was larger defects than 3.98 MeV irradiated proton beam. It was analysis between the proton irradiation beams and the proton intensities of the irradiation. Because of the Bragg peak, SRIM results shows mainly in a certain depth of the sample to form the defect by the proton irradiation, rather than the defects to appear for the entire sample.

The Characterization of MgB2 Thin Film by Slow Positron Annihilation Spectroscopy (저에너지 양전자 소멸 분광법을 이용한 MgB2 박막 구조 특성)

  • Lee, C.Y.;Kang, W.N.;Nagai, Y.;Inoue, K.;Hasegawa, M.
    • Journal of the Korean Vacuum Society
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    • v.17 no.2
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    • pp.160-164
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    • 2008
  • The Characterization of $MgB_2$ Thin Film by Slow Positron Annihilation Spectroscopy Enhance signal-to-noise ratio, slow positron coincidence Doppler Broadening method has been applied to study of characteristics of $MgB_2$ superconductor film, which were performed at 30 K and 50 K sample temperature near Tc of it. In this investigation the numerical analysis of the Doppler spectra was employed to the determination of the shape parameter, S, defined as the ratio between the amount of counts in a central portion of the spectrum and the total counts of whole spectrum. The S-parameter values were increased then decreased while the positron implantation energies were increasing, that indicated the diffusion into the samples. The S-parameters of the anisotropic 1 ${\mu}m$ $MgB_2$ thin film which were implanted by positrons at 10 keV are 0.567 at 30 K and 0.570 at 50 K. It is believed that the positrons annihilate with normal-electrons instead of super-electrons in the $MgB_2$ superconductor.

The Development of Signal Processing Software for Single-and Multi-Voxel MR Spectroscopy (단위용적 및 다용적 기법 자기공명분광 신호처리 분석 소프트웨어의 개발)

  • Paik, Moon-Young;Lee, Hyun-Yong;Shin, Oun-Jae;Eun, Choong-Ki;Mu, Chi-Woong
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.39 no.5
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    • pp.544-555
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    • 2002
  • The aim of this study is to develop the $^1H$-MRS data postprocessing software for both single-voxel and multi-voxel technique, which plays and important role as a diagnostic tool in clinical field. This software is based on graphical user interface(GUI) under windows operating system of personal computer(PC). In case of single-voxel MRS, both of raw data in time-domain and spectrum data in frequency-domain are simultaneously displayed in a screen. Several functions such as DC correction, zero filling, line broadening, Lorentz-Gauss filtering and phase correction, etc. are included to increase the quality of spectrum data. In case of multi-voxel analysis, spectroscopic image reconstructed by 3-D FFT was displayed as a spectral grid and overlapped over previously obtained T1- or T2-weighted image for the spectra to be spatially registered with the image. The analysis of MRS peaks were performed by obtaining the ratio of peak area. In single-voxel method, statistically processed peak-area ratios of MRS data obtained from normal human brain are presented. Using multi-voxel method, MR spectroscopic image and metabolite image acquired from brain tumor are demonstrated.