نتایج جستجو برای: pulse sequence
تعداد نتایج: 491602 فیلتر نتایج به سال:
Introduction: A reduced specific absorption rate (SAR) version of pseudo-continuous arterial spin labeling (pCASL) pulse sequence (1,2) is designed and implemented. Using a simulation study, a set of pCASL pulse sequence parameters is found that allows reducing the flip angle of pCASL radio frequency (RF) pulses (and consequently SAR) without losing the inversion efficiency. The proposed set of...
We present a new technique for producing two- and three-dimensional Rashba-type spin-orbit couplings for ultracold atoms without involving light. The method relies on a sequence of pulsed inhomogeneous magnetic fields imprinting suitable phase gradients on the atoms. For sufficiently short pulse durations, the time-averaged Hamiltonian well approximates the Rashba Hamiltonian. Higher order corr...
We demonstrated a new scheme for performing the T1-enhanced whole-brain black-blood imaging pulse sequence using motion-sensitized driven-equilibrium prepared 3-dimensional (3D) turbo spin echo (MSDE-TSE) with anti-driven-equilibrium post pulse. The use of an anti-driven-equilibrium pulse considerably improved the T1 contrast of MSDE-TSE black-blood images. This sequence can be used for whole-b...
Polarization for Au/Pb(Zr Ti )O /YBa Cu O ferroelectric capacitor has been studied and measured by pulse method. A sequence of pulses with amplitudes varying from 0 to 10 volts in 2 volt steps is applied and a conventional polarization curve is obtained by integrating the charge flow from the polarization switching induced by the voltage ramp. A value of 25?C/cm2 is measured for the satur...
(a) The pulse sequence used was pulsed magnetic-field gradient-90° pulse-pulsed magnetic-field gradient4elay-9O0 pulse-acquisition. Two values of the interval between saturation and observation pulses were used: A, 200ms; A, 75 ms. Typical error bars are indicated. (b) The pulse sequence used was 90,0-(z,180,0-r2),, zI = z2 = lms, n = 5 12. At the end of each r, the outputs of the two phase-sen...
The symmetry principles of NMR pulse-sequence design are summarized. The discussion is guided by an analogy with tiling schemes in the decorative arts. The symmetry operations for NMR pulse sequences are discussed in terms of excitation field modifiers and temporal modifiers. The quantum operators which describe the effect of these modifiers on the excitation field spin Hamiltonian are provided...
Fig. 1: General scheme for spin echo based SER-EPI sequence: The standard SER-scheme is extended not only by the refocusing 180 RF-pulse but also by a gradient pulse in phase-encoding direction. This gradient prephasing pulse aligns the gradient echo with the spin echo of the first excitation pulse s1. Fig.2: k-space data of spin-echo based SER-EPI sequence: Phase-encode direction is top to bot...
Optimized myo-inositol (mI) detection is important for diagnosing and monitoring a multitude of pathological conditions of the brain. Simulations are presented in this work, performed to decide which pulse sequence has the most significant advantage in terms of improving repeatability and accuracy of mI measurements at 3T over the pulse sequence used typically in the clinic, a TE = 35 ms PRESS ...
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