• 제목/요약/키워드: Resonance Region

검색결과 623건 처리시간 0.024초

Evaluation of Neutron Cross Sections of Dy Isotopes in the Resonance Region

  • Oh, Soo-Youl;Gil, Choong-Sup;Jonghwa Chang
    • Nuclear Engineering and Technology
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    • 제33권1호
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    • pp.46-61
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    • 2001
  • The neutron cross sections of $^{160}$ Dy, $^{161}$ Dy, $^{162}$ Dy, $^{l63}$Dy, and $^{164}$ Dy have been evaluated in the resonance region of which upper energy is set to several tens of keV. The cross sections are formulated with resonance parameters in the energy region under consideration. In the resolved resonance region, the positive-energy resonance parameters were adopted from the BNL compilation published in 1984 with slight, if any, modifications. A bound level resonance for each isotope except $^{162}$ Dy was invoked to reproduce the reference 2200 m/s cross sections and the bound coherent scattering length. Subsequently, the statistical behavior of the resolved resonance parameters was analyzed, and thus obtained s-wave average parameters were adopted in the unresolved resonance region. In addition, recent measurements of the capture cross sections in the unresolved region were taken into account in adjusting the average resonance parameters for high orbital angular momentum resonances. The present evaluation resulted in large improvements in the cross sections over the ENDF/B-Vl release 6.6.

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Estimation of Neutron Absorption Ratio of Energy Dependent Function for $^{157}Gd$ in Energy Region from 0.003 to 100 eV by MCNP-4B Code

  • Lee, Sam-Yol
    • 한국방사선학회논문지
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    • 제3권3호
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    • pp.23-25
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    • 2009
  • Gd-157 material has very large neutron capture cross section in the thermal region. So it is very useful to shield material for thermal neutrons. Futhermore, in the neutron capture experiment and calculation, the neutron absorption and scattering are very important. Especially these effects are conspicuous in the resonance energy region and below the thermal energy region. In the case of very narrow resonance, the effect of scattering is to be more considerable factor. In the present study, we obtained energy dependent neutron absorption ratios of natural indium in energy region from 0.003 to 100 keV by MCNP-4B Code. The coefficients for neutron absorption was calculated for circular type and 1 mm thickness. In the lower energy region, neutron absorption is larger than higher region, because of large capture cross section (1/v). Furthermore it seems very different neutron absorption in the large resonance energy region. These results are very useful to decide the thickness of sample and shielding materials.

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자기공명영상에서 다양한 구조들을 고려한 비선형 이방성 필터링 (Nonlinear Anisotropic Filtering with Considering of Various Structures in Magnetic Resonance Imaging)

  • 송영철
    • 대한전기학회논문지:시스템및제어부문D
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    • 제52권3호
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    • pp.148-155
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    • 2003
  • In this paper, a nonlinear anisotropic filtering method without the loss of important information happened due to the repeated filtering in magnetic resonance images is proposed. First of all original images are divided into four regions, e.g., SPR(Strong Plain Region), EPR(Easy Plain Region), SER(Strong Edge Region), and EER(Easy Edge Region). An optimal template among multiple templates is selected, then the nonlinear anisotropic filtering based on the template is applied in pixel by pixel basis. In the proposed algorithm, filtering strength of EER containing important information is adjusted very weak and filtering strength for remaining regions is also adjusted according to the degree of the importance. In spite of repeated filtering, resulting images by the proposed method could still preserve anatomy information of original images without any degradation. Compared to the existing nonlinear anisotropic filtering, the proposed filtering method with multiple templates provides higher reliability for filtered images.

Backbone assignment of the intrinsically disordered N-terminal region of Bloom syndrome protein

  • Min June Yang;Chin-Ju Park
    • 한국자기공명학회논문지
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    • 제27권3호
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    • pp.17-22
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    • 2023
  • Bloom syndrome protein (BLM) is a pivotal RecQ helicase necessary for genetic stability through DNA repair processes. Our investigation focuses on the N-terminal region of BLM, which has been considered as an intrinsically disordered region (IDR). This IDR plays a critical role in DNA metabolism by interacting with other proteins. In this study, we performed triple resonance experiments of BLM220-300 and presented the backbone chemical shifts. The secondary structure prediction based on chemical shifts of the backbone atoms shows the region is disordered. Our data could help further interaction studies between BLM220-300 and its binding partners using NMR.

Calculation of Energy Dependent Neutron Correction Coefficient Ratios of Natural Rhodium in Energy Region from 0.003 to 100 eV

  • Lee, Sam-Yol
    • 한국방사선학회논문지
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    • 제2권3호
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    • pp.33-35
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    • 2008
  • In the neutron capture experiment and calculation, the neutron absorption and scattering are very important. Especially these effects are conspicuous in the resonance energy region and below the thermal energy region. In the present study, we obtained energy dependent neutron absorption ratios of natural rhodium in energy region from 0.003 to 100 eV by MCNP-4B Code. The coefficients for neutron absorption was calculated for several types of thickness. In the lower energy region, neutron absorption is larger than higher region, because of large capture cross section (1/v). Furthermore it seems very different neutron absorption in the large resonance energy region. These results are very useful to decide the thickness of sample and shielding materials.

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Line-profile Formula in the Carbon Nanotubes by Electron Spin Resonance

  • Park, Jung-Il;Lee, Haeng-Ki
    • 한국자기공명학회논문지
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    • 제16권1호
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    • pp.11-21
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    • 2012
  • The line-width of carbon nanotubes (CNTs) was studied as a function of the temperature at a frequency of 9.49 GHz in the presence of external electromagnetic radiation. The relative frequency dependence of the absorption power is obtained with the projection operator technique (POT) proposed by Kawabata. The line-width increased as the temperature increased in the high-temperature region (T>200 K). The scattering is little affected in the low-temperature region (T<200 K) because there is no correlation between the resonance field and the Fermi-Dirac distribution function. Thus, the present technique is considered to be more convenient to explain the resonant system as in the case of other optical transition problems.

Double Resonance Spectra Involving Torsional Excited Levels and CO Stretch Band Transitions of $CD_3OH$

  • Choi, Sung-Eul
    • 한국광학회지
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    • 제6권2호
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    • pp.165-171
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    • 1995
  • Infrared-Radio frequency double resonance (IRRFDR) and Infrared-Microwave double resonance (IRMWDR) spectroscopy have been used to probe a level of A symmetry for $CD_{3}$OH. Double resonance spectra of $CD_{3}$OH have been investigated over the range of 940 to 1020 $cm ^{-1}$ . Twenty K-type doublet transitions have been observed in both the radio frequency region, which covers 50 MHz to 1 GHz, and the microwave region, which covers 8 GHz to 12 GHz. The results propose new assignments of infrared (IR) absorption transitions and far-infrared (FIR) laser emission lines. These involve torsional excited levels and CO stretch states. Measurements of the A state splitting have permitted the determination of the asymmetry splitting parameters $S^{o}$(n, K) and $^{co}$ (n, K) for (n, K)=(0.3) and (1.3)

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광섬유 인선 공정에 의해 생성된 실리카 광섬유내 점결함 (Fiber Drawing Induced Defects in Silica Optical Fiber)

  • 안병길;이종원;김효태
    • 한국세라믹학회지
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    • 제40권11호
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    • pp.1102-1105
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    • 2003
  • 광섬유 인선공정에 의해 생성된 실리카 유리내 점결함을 조사하였다. 본 연구에서는 특히 OH기가 적은 실리카 광섬유내 광섬유 인선 공정이 유발하는 oxygen deficient center와 E' center를 중점적으로 조사하였다. 광섬유 인선공정에 의해 oxygen deficient center 와 E’ center가 생성되었다는 것을 광학적 흡수대와 electron spin resonance를 이용하여 밝힐 수 있었다. 실리카 광섬유모재에서 가느다란 광섬유로 변환하는 neck-down 부분에서 점결함의 변화를 조사하였다. 점결함은 neck-down 부분에서 생성되며, 중심부분 보다 가장자리 부분에서 더 많은 점결함이 생성되었음을 알 수 있었다.

레이저 자기공명 분광기용 광대역 CO 레이저의 개발 (Development of a Broad-Band CO laser for the Laser Magnetic Resonance Spectrometer)

  • 김용평
    • 한국광학회:학술대회논문집
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    • 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
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    • pp.70-72
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    • 1989
  • The laser magnetic resonance (LMR) which makes use of paramagnetic properties of transient species is a powerful technique for the study of molecular radical ions. A liquid nitrogen cooled cw CO laser is developed for the LMR spectrometer in the mid-infrared region of the spectrum. The laser mid-infrared region of the spectrum. The laser system is designed to allow broad-band operation from 5 to 8${\mu}{\textrm}{m}$. The design details will be presented.

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