in this paper, dynamical behavior of the delay mechanism of a special projectile controller is studied, using 3d finite element simulation. the controller considered here is among of high-acceleration mechanical controllers. due to high linear and angular accelerations of the projectile and also explosion risk, experimental investigation is very limited and almost impossible. so, numerical simu...

We describe the use of a transverse field RF surface coil that improves 1.5 T proton MR spectroscopy in the human calf. A 2-element figure-of-eight (FO8) transverse field RF surface coil (diameter 2R=10 cm; separation between the two linear current elements 2s=1cm) and a circular loop (CL) coil of equal diameter where built and tested with proton PRESS spectra at 1.5 T. The H PRESS spectra obta...

BACKGROUND AND PURPOSE Coil compaction is thought to be the main mechanism for recurrence in cerebral aneurysms with previously successful coil embolization. We hypothesize that sac growth may be equally or more important. The objective was to study the relative roles of coil compaction and sac growth as explanations for aneurysm recurrence requiring retreatment in a study population using quan...

Introduction Parallel imaging using coil arrays with large number of receive elements allows improved imaging performance and increased SNR [1, 2]. However, the use of a large number of coil elements can lead to memory storage problems and to increased reconstruction times. Several techniques for data reduction were presented, realized either by linear combination of the original coil data or b...

In eddy current non-destructive testing of a multi-layered riveted structure, rotating current excitation, generated by orthogonal coils, is advantageous in providing sensitivity to defects of all orientations. However, when used with linear array sensors, the exciting magnetic flux density (Bx) of the orthogonal coils is not uniform over the sensor region, resulting in an output signal magnitu...

Introduction:  Image  distortion  is  one  of  the  major  problems  of  magnetic  resonance  imaging  (MRI) for use in 3DMRI, velocity MRI, FMRI and radiotherapy treatment planning (RTTP). It is  widely known that the most obvious effect of the inhomogenity of the magnetic fields and the  nonlinearity  of  the  gradient  is  the  Geometric  Distortion  of  MR  tomograms.  In  this  study,  the...

This study evaluated the accuracy of measuring the motion of an internal target using four-dimensional computed tomography (4DCT) scanning and the BrainLAB ExacTrac X-ray imaging system. Displacements of a metal coil implanted in a commercial respiratory phantom were measured in each system and compared to the known motion. A commercial respiratory motion phantom containing a metal coil as a su...

We have synthesized an amphiphilic triblock coil-rod-coil molecule consisting of a rigid aromatic building block and poly(ethylene oxide). The coil-rod-coil molecule was observed to assemble into a cylindrical micelle structure in aqueous solution. Notably, addition of a small amount of a rod-coil-rod molecule into the cylindrical micellar solution can induce the anisotropic gelation due to dyn...