High frequency oscillations are associated with normal brain function, but also increasingly recognized as potential biomarkers of the epileptogenic brain. Their role in human cognition has been predominantly studied in classical gamma frequencies (30– 100 Hz), which reflect neuronal network coordination involved in attention, learning and memory. Invasive brain recordings in animals and humans...

This paper presents a mathematical analysis of the ripple voltage caused by a mismatch in parasitic capacitances in multi-phase, clocked charge pumps. Through detailed circuit modeling, we show that a relatively large pedestal ripple is caused by a small mismatch in parasitic capacitance. We present a simple circuit solution and verify its performance with simulation and experimental results.

Coarsening of sand ripples is studied in a one-dimensional stochastic model, where neighboring ripples exchange mass with algebraic rates, Gamma(m) approximately m(gamma), and ripples of zero mass are removed from the system. For gamma<0, ripples vanish through rare fluctuations and the average ripple mass grows as (t) approximately -gamma(-1)ln(t). Temporal correlations decay as t(-1/2) or ...

Fast oscillations or "ripples" are found in the local field potential (LFP) of the rodent hippocampus during awake and sleep states. Ripples have been found to correlate with memory related neural processing, however, the functional role of the ripple has yet to be fully established. We applied a Kalman smoother based estimator of instantaneous frequency (iFreq) and frequency modulation (FM) to...

Aligned samples of lipid bilayers have been fully hydrated from water vapor in a different type of x-ray chamber. Our use of aligned samples resolves issues concerning the ripple phase that were ambiguous from previous powder studies. In particular, our x-ray diffraction data conclusively demonstrate that, on cooling from the L alpha to the P beta' phase, both chiral and racemic samples of dipa...

The effect of alpha-tocopherol on the structure and phase behavior of dilauroyl-, dimyristoyl-, dipalmitoyl-, and distearoyl-phosphatidylcholines was examined using X-ray diffraction and freeze-fracture electron microscopic methods. A ripple phase was observed in all of the mixtures at temperatures well below the pretransition temperature of the corresponding pure phospholipid. Freeze-fracture ...

The combined e ect of nonlinear elds and tune ripple can lead to chaotic motion and particle loss in proton accelerators thereby limiting the dynamic aperture of these machines. The SPS Dynamic Aperture Experiment is performed to study a controlled nonlinear machine under the in uence of power supply ripple. To this end eight strong sextupoles are used to make the SPS nonlinear. The tune ripple...

The open-loop torque control of synchronous motors with minimum torque ripple and minimum copper losses is presented. The control problem is viewed as an optimization problem for the nonlinear mapping from desired torque and position to the motor's phase currents. The performance of the controller to produce virtually ripple-free torque and to enhance the precision of position tracking is demon...

This study focuses on the mixed-chain lipid myristoylpalmitoylphosphatidylcholine (MPPC) near full hydration. The lipid, synthesized according to the procedure of (Mason et al., 1981a, has a low degree of acyl chain migration. When MPPC is temperature-jumped (T-jumped) from the L alpha phase (T = 38 degrees C) to T = 20 degrees C or below, a subgel phase forms; this formation takes less than 1 ...

In this paper, a new bidirectional buck-boost dc-dc converter with capability of soft switching and zero input current ripple is proposed. The coupled inductor is used in the proposed converter to eliminate the input current ripple. In the proposed converter, zero voltage switching (ZVS) and zero current switching (ZCS) can be obtained for the main and auxiliary switches, respectively. In addit...