Academic literature on the topic 'Vector magnetization characteristics'

AbstractTo enhance internal combustion engine performance, this study focuses on developing an electric valve drive system utilizing linear actuators for intake and exhaust valve control. The linear actuator, comprising a movable coil and a fixed permanent magnet, operates based on the principle of the Lorentz force. Unlike traditional magnetic circuits, this actuator employs five permanent magnets with different magnetization directions to concentrate the flux on the coil. In this study, multiple models with varying ratios of these permanent magnets were created and analyzed using finite element analysis conducted with the JMAG software to investigate the thrust characteristics during the reciprocating motion of the actuator. The vector plot of the magnetic flux density shows that the magnetic circuit is predominantly composed of permanent magnets. The average thrust at a 10 mm displacement was approximately 107 N in the largest model. Future studies will aim to design actuators with increased thrust capabilities.

Abstract Very soon after the initial discovery of nuclear magnetic resonance, E. L. Hahn performed an experiment that, in conceptual originality and elegance, transcended all that had preceded it-the spin echo experiment [1]. Here was an idea to inspire the young scientists reading about NMR for the first time. Not only could oneworkwith these strange new entities called spins, but alsomanipulatethem like a conjuror with a pack of cards. In its original form, experiment was conceptually easier to follow, resembling the opening and closing of a ‘fan’ of vectors confined to the transverse(x-y)plane of the rotating frame. Note that the description of the conventional continuous wave NMR experiments of the time scarcely required this level of sophistication, relying on the steady state solutions of the Bloch equations. To understand spin echoes, one was forced to come to grips with homogeneous and inhomogeneous line broadening, transformation into the rotating frame of reference, and the concept of ‘spin isochromats’. This was a term coined by Abragam [3]. The sample is considered to be made up of a mosaic of volume elements, each small enough that the variation of the applied field intensity across that element could be neglected, but with neighbouring elements in slightly different applied fields due to the spatial inhomogeneity. Each element has a nuclear magnetization with a characteristic precession frequency; this is an isochromat. The total sample magnetization is the resultant of all these isochromatic magnetization vectors. Because the isochromats have different intrinsic frequencies this resultant can change as individual isochromats fan out or come back into alignment. This has proved a valuable idea for describing spin echo experiments.

Experimentally and using numerical simulation the process of excitation of high-frequency oscillations in a nonlinear transmission line with saturated ferrite, depending on the polarity of the incident voltage pulse, was studied. As part of the work, an effect was discovered in which the voltage pulses generated at the output of the transmission line depend on the direction of rotation of the magnetization vector of the ferrite filling. The shape and characteristics of these pulses were studied and compared depending on the polarity of the incident voltage pulse.

Abstract A method for crack detection on the surface of pipelines that uses residual magnetic detection technology based on the hysteresis effect after magnetizing the pipeline to magnetic saturation has been developed in this study. Support vector regression (SVR) was employed for quantitative assessment. This paper reviewed the magnetization process of the magnetizer, the generation of residual magnetism effect, and the detection of residual magnetic fields. An experimental and theoretical study examined how the crack size affects residual magnetic anomalies. The simulation results indicated

Petro- and paleomagnetic studies of Early Paleozoic rocks of carbonate basement of a number of diamond deposits in the Yakutsk diamondiferous province were carried out to study changes in the values of petrophysical parameters in the zone of dynamic influence of a kimberlite pipe. It is shown that during the formation of kimberlite diatrems accompanied by pulsational, upward-shifting explosions, thermoelastic stress fields characterized by epigenetic changes and related petrophysical aureoles appear in the kimberlite-bearing medium. Naturally, some of these petrophysical aureoles are petromagn