Search results for "Maximum amplitude"
showing 3 items of 3 documents
Accommodative Functions with Multifocal Contact Lenses: A Pilot Study
2011
PURPOSE: To evaluate accommodative response and facility in presbyopic patients fitted with several types of simultaneous-image multifocal contact lenses (CLs). METHODS: Six presbyopic patients, unadapted wearers of simultaneous-image bifocals, were fitted with the Focus Progressives and the low- and high-addition Pure Vision simultaneous vision multifocal CLs. Each individual wore each of the three types of lenses in successive random order. Accommodative response, accommodative facility, visual acuity, and contrast sensitivity at distance and near were evaluated in all cases. A control group of eight non-presbyopic patients was also studied. RESULTS: The mean age was 28.6 +/- 2.72 and 51.…
Towards the time-optimal control of dissipative spin-1/2 particles in nuclear magnetic resonance
2011
International audience; We consider the time-optimal control of a spin 1/2 particle whose dynamics is governed by the Bloch equations with both longitudinal and transverse relaxation terms. We solve this control problem by using geometric optimal control techniques. We show the crucial role of singular extremals in the time-optimal synthesis. This role can mainly be attributed to the presence of dissipation. We also analyze the robustness of the optimal control sequence when both the maximum amplitude of the control field and the dissipative parameters are varied. Finally, we present an experimental implementation of the different solutions using techniques of Nuclear Magnetic Resonance.
Distortion product otoacoustic emissions in healthy newborns: normative data.
1995
Distortion product otoacoustic emissions (DPOAE) offer an alternative to transiently evoked otoacoustic emissions (TEOAE) as an audiological test. The former can be used as a screening technique, and may also provide frequency-specific information about the functional state of the cochlea. We recorded DPOAE in a group of healthy newborns to establish the Characteristics of a DPOAE “audiogram” (DP-gram) in this population. The DP-gram can be obtained with characteristics quite similar to those observed in adults, with two sharp peaks of maximum amplitude at F2 frequencies of 2 kHz and 5-6 kHz, and a decline in DPOAE amplitude in mid frequencies. The results confirm the limitations of DPOAE r…