• Title/Summary/Keyword: 스핀

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Robust 3D Facial Landmark Detection Using Angular Partitioned Spin Images (각 분할 스핀 영상을 사용한 3차원 얼굴 특징점 검출 방법)

  • Kim, Dong-Hyun;Choi, Kang-Sun
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.5
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    • pp.199-207
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    • 2013
  • Spin images representing efficiently surface features of 3D mesh models have been used to detect facial landmark points. However, at a certain point, different normal direction can lead to quite different spin images. Moreover, since 3D points are projected to the 2D (${\alpha}-{\beta}$) space during spin image generation, surface features cannot be described clearly. In this paper, we present a method to detect 3D facial landmark using improved spin images by partitioning the search area with respect to angle. By generating sub-spin images for angular partitioned 3D spaces, more unique features describing corresponding surfaces can be obtained, and improve the performance of landmark detection. In order to generate spin images robust to inaccurate surface normal direction, we utilize on averaging surface normal with its neighboring normal vectors. The experimental results show that the proposed method increases the accuracy in landmark detection by about 34% over a conventional method.

Diagnosis of Meniscal Tear of the Knee Using Proton-weighted Fast Spin-Echo MR Imaging : Can be an Alternative to Conventional Spin-Echo Imaging\ulcorner (양지밀도강조 고속 스핀에코 자기공명영상을 이용한 슬관절 반월판 열상의 진단 : 고식적 스핀에코를 대체할 수 있는가\ulcorner)

  • 김기준;이재희;주종관;이성용
    • Investigative Magnetic Resonance Imaging
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    • v.3 no.1
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    • pp.73-77
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    • 1999
  • Purpose : The purpose of the study was to evaluate the sensitivity and specificity of proton-weighted fast spin-echo MR imaging in diagnosing the meniscal tear of knee as an reasonable substitute for conventional spin-echo imaging. Materials and Methods : 102 consecutive patients, proved by surgery, proved by surgery, were participated in this study. All of them were suspected internal derangement of knee, examined by fast spin-echo MR imaging including sagittal and coronal images on a 1.5T MR imager and underwent arthroscopic or open surgery of knee joint within 2 months. These images were reviewed retrospectively by three radiologists. The sensitivity and specificity of meniscal tear were calculated. Results : The sensitivity and specificity of meniscal tear using proton-weighted fast spin-echo MR imaging were 94%, 93% inmedialmeniscus and 92%, 88% in lateral meniscus. Conclusion : The sensitivity and specificity of meniscal tear using proton weighted fast-spin echo MR images were as high as those using conventional spin-echo images. The proton-weighted fast-spin echo MR imaging can be an alternative to conventional spin-echo MR imaging in diagnosing meniscal tear of the knee.

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Magnetoresistance of IrMn-Based Spin Filter Specular Spin Valves (IrMn 스핀필터 스페큘라 스핀밸브의 자기저항 특성)

  • Hwang, J.Y.;Rhee, J.R.
    • Journal of the Korean Magnetics Society
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    • v.14 no.6
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    • pp.236-239
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    • 2004
  • We studied the specular spin valve (SSV) having the spin filter layer (SFL) in contact with the ultrathin free layer composed of Ta3/NiFe2/IrMn7/CoFel/(NOLl)/CoFe2/Cu1.8/CoFe( $t_{F}$)/Cu( $t_{SF}$ )/(NOL2)/Ta3.5 (in nm) by the magnetron sputtering system. For this antiferromagnetic I $r_{22}$M $n_{78}$-pinned spin filter specular spin valve (SFSSV) films, an optimal magnetoresistance (MR) ratio of 11.9% was obtained when both the free layer thickness ( $t_{F}$) and the SFL thickness ( $t_{SF}$ ) were 1.5 nm, and the MR ratio higher than 11% was maintained even when the $t_{F}$ was reduced to 1.0 nm. It was due to increase of specular electron by the nano-oxide layer (NOL) and of current shunting through the SFL. Moreover, the interlayer coupling field ( $H_{int}$) between free layer and pinned layer could be explained by considering the RKKY and magnetostatic coupling. The coercivity of the free layer ( $H_{cf}$ ) was significantly reduced as compared to the traditional spin valve (TSV), and was remained as low as 4 Oe when the $t_{F}$ varied from 1 nm to 4 urn. It was found that the SFL made it possible to reduce the free layer thickness and enhance the MR ratio without degrading the soft magnetic property of the free layer.

Preparation of High Spin Five-Coordinate Iron(II) Complexes of 1,4,8,11-Tetraazacyclotetradecane and High Spin Six-Coordinate Iron(II) Complexes of 1,5,8,12-Tetraazadodecane (1,4,8,11-테트라아자사이클로테트라데칸의 높은 스핀 다섯배위철(II) 착화합물과 1,5,8,12-테트라아자도데칸의 높은 스핀 여섯배위철(II) 착화합물의 합성)

  • Myunghyun Paik Suh
    • Journal of the Korean Chemical Society
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    • v.24 no.2
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    • pp.139-145
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    • 1980
  • High spin iron(II) complexes of 1,4,8,11-tetraazacyclotetradecane (cyclam), a macrocyclic ligand, and 1,5,8,12-tetraazadodecane (3,2,3-tet), a noncyclic ligand, have been prepared. The reaction of low spin $[Fe(cyclam)(CH_3CN)_2](ClO_4)_2$ with chloride ion in methanol produces high-spin $[Fe(cyclam)Cl]ClO_4$. Although $[Fe(cyclam)(CH_3CN)_2](ClO_4)_2$ is low spin, $[Fe(3,2,3-tet)(CH_3CN)_2](ClO_4)_2$ isolated in the present study is high spin. This difference is explained in terms of the smaller constrictive effect exerted by the noncyclic ligand than the cyclic ligand. The isolation of $[Fe(cyclam)Cl]ClO_4$ provides evidences against the current view that the presence of either unsaturation or substituents on the macrocyclic ligands is necessary for the successful preparation of high spin five-coordinate iron (II) complexes. Reactions of $[Fe(cyclam)Cl]ClO_4\;and\;[Fe(3,2,3-tet)(CH_3CN)_2](ClO_4)_2$ with carbon monoxide yield low spin six-coordinate $[Fe(cyclam)Cl(CO)]ClO_4\;and\;[Fe(3.2,3-tet)(CH_3CN)(CO)](ClO_4)_2$, respectively.

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Dynamic Responses in Ultra-Soft Magnetic Thin Films (초 연자성 박막에서의 동적 자화 거동)

  • 정인섭
    • Journal of the Korean Magnetics Society
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    • v.4 no.1
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    • pp.1-6
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    • 1994
  • The magnetization dynamics was investigated by solving possible origins of overdamped susceptibility observed in ultra-soft magnetic amorphous thin films. The experimental high frequency spectrum and computational spectrum calculated from Gilbert's equation of motion were compared in order to find proper damping factor $\alpha{\approx}20$ and demagnetizing coefficients $D_{x}{\approx}D_{y}{\approx}D_{z}{\approx}0$ for ultra-soft magnetic films. A magnetization vortex mode was, then, proposed to explain the origin of the reversible susceptibility and other anomalies of the ultra-soft magnetic heterogeneous thin films. In this mode it is suggested that there occur, within the nanoscale structural features of the ultra-soft films, incoherent rotational spin motions that are highly damped by the energy transfer from short wavelength spin wave modes and local defect structure mode interactions.

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Application of Tensor Theory to Pulse Sequences

  • 정관진
    • Proceedings of the KSMRM Conference
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    • 2001.11a
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    • pp.57-63
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    • 2001
  • Tensor 하면 최근 3D로 white matter내의 섬유질을 멋있게 그려내는 diffusion tensor를 연상합니다. 하지만 여기서 다룰 tensor는 수학적 연산자(operator)입니다. NMR 혹은 MRI에서 스핀을 vector로 표시하고, 이 vector 스핀이 90도 rf pulse에 의해서 z축에서 x-y Plane으로 rotation되는 것을 vector diagram으로 나타냅니다. 그런데 이 vector notation으로는 스핀에 일어나는 여러 현상들을 수식적으로 모델 하는데 한계가 있습니다. 그래서 도입된 모델이 product operator와 tensor operator입니다 (1, 2, 3). 한 예로 우리가 다루는 proton NMR 신호가 single quantum인데 23Na 등에는 multiple quantum 신호가 생기게 되며 이는 vector로는 나타낼 수가 없으며 tensor로 분석이 가능합니다 (4, 5).

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