The role of the amplitude, number, and duration of unipolar rectangular electric pulses in cell membrane electropermeabilization in vitro has been the subject of several studies. With respect to unipolar rectangular pulses, an improved efficiency has been reported for several modifications of the pulse shape: separate bipolar pulses, continuous bipolar waveforms, and sine-modulated pulses. In t...

A major limitation of many functional electrical stimulation (FES) applications is that muscles tend to fatigue very rapidly. It was hypothesized that FES-induced muscle fatigue could be reduced by randomly modulating the pulse frequency, amplitude, and pulse width in a range of +/-15%. Seven subjects with spinal-cord injuries participated in this study. FES was applied to quadriceps and tibial...

High current qualities and high efficiencies are always two important characteristics for power converters. However, it is challenging to achieve the targets simultaneously. In this paper, dead-time-effect elimination pulse-width-modulation (PWM) improving discontinuous PWM (DPWM) reducing switching losses combined, proposing a double-modulation-wave DPWM. An additional modulation wave added, w...

The focus of this paper is on adaptive control of maneuvering rigid bodies in the presence of friction. The paper describes a simple technique which include Pulse Amplitude and Pulse Width modulation to progressively move the system to the desired final position. To account for uncertainty in estimated friction coefficients and approximated system model, an adaptation algorithm is necessary to ...

In this paper, a novel pulse shaping method is presented for Orthogonal frequency division multiplexing with offset quadrature amplitude modulation (OFDM/OQAM) systems. Designed as a linear combination of normalized Hermite functions, the proposed pulse is optimized with respect to interference caused by insufficient synchronization such as carrier frequency offset (CFO) and timing offset (TO)....

We demonstrate fast nonlinear optical switching between two laser pulses with as few as 140 photons of pulse energy by utilizing strong coupling between a single quantum dot (QD) and a photonic crystal cavity. The cavity-QD coupling is modified by a detuned pump pulse, resulting in a modulation of the scattered and transmitted amplitude of a time synchronized probe pulse that is resonant with t...

We demonstrate a new experimental approach for flexible femtosecond pulse generation in the mid-IR by use of difference-frequency generation from two tightly synchronized Ti:sapphire lasers. The resultant mid-IR pulse train can be easily tuned, with an adjustable repetition frequency up to 100 MHz, a pulse energy of approximately 1.5 x 10(-13) J, and an intensity noise similar to that of the Ti...

Introduction At higher static field strengths of 7T and above specific absorption rate (SAR) and acoustic sound pressure level (SPL) pose limitations on the pulse sequence design. To overcome SAR limitations, the VERSE principle can be used [1]. Here, the envelope of existing rf pulses are modified together with the shape of the slice-selection gradient to selectively reduce high B1 amplitudes ...

this paper presents a novel control method to improve the efficiency of low-voltage dc-dc converters at light loads. pulse width modulation (pwm) converters have poor efficiencies at light loads, while pulse frequency modulation (pfm) control is more efficient for the same cases. switching losses constitute a major portion of the total power loss at light loads. to decrease the switching losses...

Z. Naturforsch. 66a, 411 – 416 (2011); received October 11, 2010 / revised January 8, 2011 By means of the linear approximation method, the output intensity power and signal-to-noise ratio (SNR) of a single-mode laser driven by sine-squared pulse modulation correlated noise are calculated. The effects of amplitude B, period T , and width τ on the resonance curves of SNR to the pump noise intens...