Search results for "Anisotropy"

Orientation of199mHg by optical pumping detected by ?-radiation anisotropy

1975

199mHg was produced and mass separated at the ISOLDE facility (CERN). Nuclear orientation achieved by optical pumping via the resonance line 6s21S0→6s6p3P1,λ=2537A was monitored by means of the anisotropy of theγ-radiation emitted in the cascade199mHg(I=13/2+) $${}^{199m}Hg(I = 13/2^ + )\xrightarrow[{M4}]{}{}^{199*}Hg(I = 5/2^ - )\xrightarrow[{E2}]{}{}^{199}Hg(I = 1/2^ - ).$$ 199*Hg(I=5/2−)199Hg(I=1/2−).

Anisotropies and Intensity Saturation of Gray-Tracking in KTiOPO/sub 4/

2005

Hygro-elasto-plastic model for planar orthotropic material

2015

An in-plane elasto-plastic material model and a hygroexpansivity-shrinkage model for paper and board are introduced in this paper. The input parameters for both models are fiber orientation anisotropy and dry solids content. These two models, based on experimental results, could be used in an analytical approach to estimate, for example, plastic strain and shrinkage in simple one-dimensional cases, but for studies of the combined and more complicated effects of hygro-elasto-plastic behavior, a numerical finite element model was constructed. The finite element approach also offered possibilities for studying different structural variations of an orthotropic sheet as well as buckling behavior…

Correlation of quenched structural disorder and magnetism inTiFe2Laves-phase thin films

2002

In recent bandstructure calculations for the $C14$ Laves-phase intermetallic compound ${\mathrm{TiFe}}_{2}$ two energetically nearly degenerate magnetic ground states (antiferromagnetic and ferromagnetic) were predicted. As a consequence of this near-degeneracy in the $C14$ stability range of ${\mathrm{Ti}}_{x}{\mathrm{Fe}}_{1\ensuremath{-}x}$ $(x\ensuremath{\approx}1/3)$ the magnetic properties are strongly correlated with the sublattices' occupation by Ti and Fe. We analyzed the magnetic properties of a series of thin epitaxial films with varying composition in the $C14$ stability range. The temperature- and field-dependent magnetic properties of these samples were determined by dc superc…

The chain length of anisotropic paramagnetic particles in a rotating field

2020

In this article, the maximal length of a chain of paramagnetic particles with magnetic anisotropy in a rotating magnetic field is studied. The theory of paramagnetic particle chains usually assumes that the particles are magnetically isotropic and do not rotate in a rotating field. In experiments it is seen that spherical paramagnetic particles rotate, which can be explained by small magnetic anisotropy. In this article, the maximal chain length is calculated for paramagnetic particles with magnetic anisotropy in a rotating magnetic field. Results show that the maximal chain length as a function of field frequency has the same trend for isotropic magnetic particles and particles with magnet…

Widespread white matter microstructural abnormalities in bipolar disorder: evidence from mega- and meta-analyses across 3033 individuals

2019

Fronto-limbic white matter (WM) abnormalities are assumed to lie at the heart of the pathophysiology of bipolar disorder (BD);\ud however, diffusion tensor imaging (DTI) studies have reported heterogeneous results and it is not clear how the clinical\ud heterogeneity is related to the observed differences. This study aimed to identify WM abnormalities that differentiate patients with\ud BD from healthy controls (HC) in the largest DTI dataset of patients with BD to date, collected via the ENIGMA network. We gathered\ud individual tensor-derived regional metrics from 26 cohorts leading to a sample size of N = 3033 (1482 BD and 1551 HC). Mean\ud fractional anisotropy (FA) from 43 regions of i…

2019

Objective: Severe malnutrition in patients with anorexia nervosa (AN) as well as possible trait-related aberrations lead to pronounced structural brain changes whose reversibility after recovery is currently unclear. Previous diffusion tensor imaging (DTI) studies investigating white matter (WM) microstructure alterations in AN are inconsistent. Methods: In this so far largest DTI study in adults, we investigated 33 AN patients, 20 recovered (REC), and 33 healthy women. DTI data were processed using the "DTI and Fiber tools," and the Computational Anatomy Toolbox. WM integrity, both in terms of fractional anisotropy (FA) and mean diffusivity (MD), was assessed. Results: We found a significa…

Anisotropic Flow of Charged Particles in Pb-Pb Collisions at √sNN = 5.02 TeV

2016

We report the first results of elliptic (v2), triangular (v3), and quadrangular (v4) flow of charged particles in Pb-Pb collisions at a center-of-mass energy per nucleon pair of √sNN p ¼ 5.02 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurements are performed in the central pseudorapidity region jηj < 0.8 and for the transverse momentum range 0.2 < pT < 5 GeV=c. The anisotropic flow is measured using two-particle correlations with a pseudorapidity gap greater than one unit and with the multiparticle cumulant method. Compared to results from Pb-Pb collisions at √sNN p ¼ 2.76 TeV, the anisotropic flow coefficients v2, v3, and v4 are found to increase by ð3.0 0.6Þ%, ð…

Magnetization dynamics in polycrystalline Permalloy and epitaxial Co platelets observed by time-resolved photoemission electron microscopy

2009

We studied the dynamic magnetization response in rectangular polycrystalline Permalloy and also epitaxial Co structures (lateral sizes comprised tens of microns at a thickness of tens of nanometers) during the action of a magnetic field pulse, using time-resolved X-ray photoemission electron microscopy with a time resolution of 10 ps. In the case of Permalloy platelets the restoring torque that is necessary for the stroboscopic image acquisition is provided by the Landau flux closure structure representing a minimum of the free energy. We investigated the dynamic response of 90° Neel domain walls. The main results are: the maximum velocity of the domain wall is 1.5 × 104 m/s, the intrinsic …

Scaling of intrinsic domain wall magneto-resistance with confinement in electromigrated nanocontacts

2018

In this work we study the evolution of intrinsic domain wall magnetoresistance (DWMR) with domain wall confinement. Clean permalloy notched half-ring nanocontacts are fabricated using a special ultra-high vacuum electromigration procedure to tailor the size of the wire in-situ and through the resulting domain wall confinement we tailor the domain wall width from a few tens of nm down to a few nm. Through measurements of the dependence of the resistance with respect to the applied field direction we extract the contribution of a single domain wall to the MR of the device, as a function of the domain wall width in the confining potential at the notch. In this size range, an intrinsic positive…