Hysteresis Shift Research Articles

Reduction of loss using the pinning inhomogeneity in Co-based amorphous ribbons

Measurements of hysteresis loops and the derivative of magnetization with time (d M/d t) vs. exciting field ( H) were performed by the induction method on straight amorphous ribbons. A direct current, passing along the ribbon, caused narrowing of the hysteresis loop and shift of peaks in the d M/d t vs. H curve. A new model proposed for the explanation of these phenomena explains well the experimental results.

Rapid resetting of rabbit aortic baroreceptors and reflex heart rate responses by directional changes in blood pressure.

In both anaesthetized and conscious rabbits, perivascular balloon inflations slowly raised or lowered mean arterial pressure (M.A.P.), at 1-2 mmHg/s, from resting to various plateau pressures. Deflations then returned the M.A.P. to resting. 'Steady-state' curves relating M.A.P. to unitary aortic baroreceptor firing, integrated aortic nerve activity and heart rate were derived during the primary and return pressure changes and they formed typical hysteresis loops. In single units, return M.A.P.-frequency curves were shifted in the same direction as the primary pressure changes by an average 0.37 mmHg per mmHg change in M.A.P. Shifts were linearly related to the changes in M.A.P. between resting and plateau levels for all pressure rises and for falls less than 30 mmHg. They were established within 30 s and were quantitatively similar to the rapid resetting of baroreceptor function curves found 15 min-2 h after a change in resting M.A.P. (Dorward, Andresen, Burke, Oliver & Korner, 1982). Unit threshold pressures were shifted within 20 s to the same extent as the over-all curve shift to which they contributed. In the whole aortic nerve, return M.A.P.-integrated activity curves were shifted to same degree as unit function curves in both anaesthetized and conscious rabbits. Simultaneous shifts of return reflex M.A.P.-heart rate curves were also seen in conscious rabbits within 30 s. During M.A.P. falls, receptor and reflex hysteresis was similar, but during M.A.P. rises, reflex shifts were double baroreceptor shifts, suggesting the involvement of other pressure-sensitive receptors. We conclude that hysteresis shifts in baroreceptor function curves, which follow the reversal of slow ramp changes in blood pressure are a form of rapid resetting. They are accompanied by rapid resetting of reflex heart rate responses. We regard this as an important mechanism in blood pressure control which produces relatively high-gain reflex responses, during slow directional pressure changes, over a wider range of absolute pressure levels than would otherwise be possible.

Effect of anodic growth temperature on native oxides of n-(Hg, Cd)Te

The insulating behavior of anodically grown native oxides on Cd0.23Hg0.77Te can be improved considerably by performing the anodic process at increased temperatures. For the first time, anodic oxides were grown at 50 °C in the standard ethylene glycol-KOH-electrolyte which show a reduction in the high-frequency (1 MHz) conductivity of the order of one magnitude respective to our room-temperature grown oxides. A high electrical breakdown voltage (1.5 MV/cm) and a decreased hysteresis shift (50 mV) underline these results. Other oxide parameters such as fixed oxide charges and fast surface states and the excellent dc resistivity remain practically unchanged. Subroom-temperature grown oxides, however, are extremely unstable.

Specific Changes in the High Resolution 1H and 13C NMR Spectra of Triethyl- and Trimethylacetic Acids at the Liquid-Solid Phase Transition

Abstract High resolution 1H and 13C NMR spectra of triethylacetic and trimethylacetic (pivalic) acids have been studied at different temperatures. A sharp decrease in the chemical shift of the carboxyl proton and hysteresis of chemical shift have been found for triethylacetic acid at the liquid-solid phase transition. A new line at 5.3 ppm has been observed for both acids in the brittle crystal phase and assigned to the signal of the non-hydrogen-bonded carboxyl proton. The difference of experimental data for the studied acids indicates, that triethylacetic acid does not exist in the plastic crystal phase.