نتایج جستجو برای: normal anisotropy

تعداد نتایج: 591040  

Journal: :NeuroImage 1999
U C Wieshmann C A Clark M R Symms F Franconi G J Barker S D Shorvon

Diffusion tensor imaging is a magnetic resonance method which provides quantitative measurements of the directionality (anisotropy) of diffusion. Anisotropy measurements can be used to obtain quantitative information about the microstructural integrity of white matter tracts. In intact tracts diffusion is restricted and directional because water molecules move predominantly longitudinally to tr...

2007
E. Ozarslan U. Nevo P. J. Basser

INTRODUCTION Diffusion imaging has traditionally been used to infer information regarding tissue microstructure when the characteristic dimensions of the underlying geometry are smaller than the voxel size. However, the diffusion signal is sensitive to structures whose sizes are comparable to or greater than the voxels of the image. In this work, using a simple system of infinite parallel plane...

2014
Yiwei Liu Baomin Wang Qingfeng Zhan Zhenhua Tang Huali Yang Gang Liu Zhenghu Zuo Xiaoshan Zhang Yali Xie Xiaojian Zhu Bin Chen Junling Wang Run-Wei Li

The magnetic anisotropy is decreased with increasing temperature in normal magnetic materials, which is harmful to the thermal stability of magnetic devices. Here, we report the realization of positive temperature coefficient of magnetic anisotropy in a novel composite combining β-phase polyvinylidene fluoride (PVDF) with magnetostrictive materials (magnetostrictive film/PVDF bilayer structure)...

Journal: :AJNR. American journal of neuroradiology 2002
Neeraj B Chepuri Yi-Fen Yen Jonathan H Burdette Hong Li Dixon M Moody Joseph A Maldjian

BACKGROUND AND PURPOSE The corpus callosum is a heterogeneous white-matter tract that connects the cerebral hemispheres. The purpose of this investigation was to study its microstructural architecture in normal human adult brains by using diffusion tensor imaging (DTI). METHODS Two hundred consecutive patients referred for brain MR imaging underwent additional DTI with a high gradient field s...

Journal: :فیزیک زمین و فضا 0
منصوره منتهایی استادیار، گروه فیزیک زمین، مؤسسة ژئوفیزیک دانشگاه تهران، ایران بنفشه حبیبیان دهکردی استادیار بخش ژئومغناطیس، مؤسسة ژئوفیزیک دانشگاه تهران

in an electrically anisotropic media, current density  is not aligned with the electric field  and varies with the e-field direction. this can be considered as the spatial aliasing effects aroused by the subsurface structures whose individual dimensions are smaller than the inductive length scale of diffusively propagating em fields. the role of these structures is particularly significant in t...

M.A.Rowshanzamir and A. Jafari,

Cohesive-frictional soils are widely used in the construction of embankment structures and due to the method of construction, i.e. applying compactive efforts in the vertical direction in these cases, the occurrence of anisotropy in the soil strength and permeability seems to be inevitable. In this study, attempts have been made to evaluate the shear strength of c-f soils through modifying a l...

2013
Jared Rowley Vladimir Fonov Ona Wu Simon Fristed Eskildsen Dorothee Schoemaker Liyong Wu Sara Mohades Monica Shin Viviane Sziklas Laksanun Cheewakriengkrai Amir Shmuel Alain Dagher Serge Gauthier Pedro Rosa-Neto

The purpose of this project was to evaluate white matter degeneration and its impact on hippocampal structural connectivity in patients with amnestic mild cognitive impairment, non-amnestic mild cognitive impairment and Alzheimer's disease. We estimated white matter fractional anisotropy, mean diffusivity and hippocampal structural connectivity in two independent cohorts. The ADNI cohort includ...

2016
K. Ghazikhanlou-sani S. M. P. Firoozabadi L. Agha-ghazvini H. Mahmoodzadeh

INTRODUCTION There is many ways to assessing the electrical conductivity anisotropy of a tumor. Applying the values of tissue electrical conductivity anisotropy is crucial in numerical modeling of the electric and thermal field distribution in electroporation treatments. This study aims to calculate the tissues electrical conductivity anisotropy in patients with sarcoma tumors using diffusion t...

Journal: :international journal of iron & steel society of iran 2008
a. r. ebrahimi a. abyazi s. m. abbasi

thermomechanical control process steel produced by rolling has a significant anisotropy. the elongated grains and inclusions formed during hot rolling of ferrite and low carbon hsla steels directly influence the anisotropy of the steel’s mechanical properties as a result of microstructural anisotropy. the present research deals with this anisotropy, and particular attention has been paid to the...

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