near-fault ground motions with long-period pulses can place severe demands on structures near an active fault. these pulse-type ground motions can be represented by pulse sequences with simple shapes. half-sinusoidal pulse sequences are used to approximate recorded ground motions and dynamic responses of sdof system under the excitation of these pulse sequences are studied. four cases are consi...

background:  nowadays mri examinations have been widely used in clinical applications for many diagnoses. the use of contrast agent in mri improves lesion detection and characterization and causes more accurate diagnosis.  objectives: the aim of this study was comparing to optimal dose of magnevist contrast agent in modified t1w se (spin echo), t1w fse (fast spin echo) and t1w gre (gradient ech...

The basic idea of parallel imaging is to reduce the number of acquisition steps (i.e. phase-encoding steps) by decreasing the sampling density in kspace. Artefacts, in particular aliasing artefacts, that would result from the reduced sampling density are compensated by employing image data from several independent coil elements with different spatial sensitivity profi les for reconstruction. Th...

Coupling constants V (I5N 13CR) and V (15N 'H R) in 2-substituted pyridines [R = Me (1), CH = CH2 (2), C = C H (3), C (0)H (4), C (0)M e (5)] have been measured by using 7/ahn-echo extended (H EED) pulse sequences for one(ID ) and two-dimensional (2D ) l3C/'H N M R (HEEDINEPT, HEED-HETCOR). The magnitude of | 2/ ( ,5N 13Cr)| is hardly affected by the hybridiza­ tion o f 13Cr . 15N N M R spectra...

Saturation Recovery The simplest sequence is known as Saturation Recovery in which there is a single 90? pulse and a long repetition time between pulses. If the signal is measured immediately following the pulse the image will depend on the proton density. If the sequence is repeated rapidly (short repetition time, TR) there will be only partial relaxation and the results will depend on proton ...

It is well known that using orthogonal polarizations for sub-pulses in multi-pulse sequences can be used to reduce clutter contributions in these modes. In this paper we show that further improvements are achieved if the orthogonality is taken into account already when constructing the codes. Using orthogonal polarizations one can use denser transmission patterns, including elementary pulses wi...