Measurements of surface magnetic fields of perpendicular and longitudinal magnetic recorded transitions using a magnetoresistive transducer

Quasi-static recording experiments employing a hybrid single-pole-type write head and a vertical magnetoresistive transducer (MRT) read head are presented. The MRT is shown to be able to measure asymmetries of the remanent magnetization of transitions recorded in perpendicular and longitudinal media. The effects of varying the write field angle by adjusting the write shim placement with respect to the auxiliary pole is shown to be useful in determining the resultant remanent magnetization. Dynamic recording responses correlate with the quasi-static measurements. A model of recorded transitions is presented which combines in-plane arctangent and vertical complementary arctangent remanent magnetization distributions.     

Purposeful delay in the repair of a traumatic rupture of the aorta with coexistent liver injury

Purposeful delay in the repair of traumatic aortic injury by appropriate medical management is indicated when the risk of immediate thoracotomy is high. A grade V liver injury implies parenchymal disruption of greater than 75% of a hepatic lobe. We report the successful management of a patient with a class IB proximal descending aortic transection and concomitant grade V liver injury that precluded aortic repair until its resolution.     

Spatial noise phenomena of longitudinal magnetic recording media

The authors have studied the spatial noise characteristics of uniformly magnetized media and implemented a synchronous magnetic pulse detection technique to measure waveforms from precise radial and azimuthal locations on a magnetically recorded disk. They introduce a correlation analysis which includes measuring noise waveforms from the same position on the disk under different remanent magnetic states. Results from this analysis demonstrate that at remanence only minor changes occur in the output waveform and its (presumed) corresponding magnetic structure from write to write, while at DC demagnetization large variations are seen for successive writes. This sensitive correlation technique is used to analyze the random and deterministic components of media and head noise     

Comparison of the magnetic recording performance of medium-scale ring, double-sided pole, metal-in-gap heads on high-coercivity longitudinal media

The magnetic recording performance of medium-scale ring, double-sided pole, and metal-in-gap (MIG) heads were investigated on standard longitudinal high-coercivity floppy, video tape, and isotropic floppy media using a stretched-surface multi-head magnetic recording tester. The isolated pulses for the ring and MIG heads exhibited sharp peaks near tbe edges of the gap for a head-medium separation of less than 0.1 um. Low density maximum output voltage was independent of the type of the write head. The largest output voltage was achieved from the MIG head. The isolated outputs on video media agreed with calculated values for the ring head efficiency set to 52% and the pole head efficiency set to 33% using the Karlqvist head field approximation.