Search results for "Pulse wave"
showing 10 items of 133 documents
ASSOCIATION OF RENAL RESISTIVE INDEX WITH CAROTID INTIMA-MEDIA THICKNESS IN HYPERTENSIVE PATIENTS
2014
Sensitivity of SHG-FROG for the characterization of ultrahigh-repetition-rate telecommunication laser sources
2004
International audience; We analyze experimentally the sensitivity of second-harmonic generation frequency-resolved optical gating (SHG-FROG) for the complete intensity and phase characterization of both a sinusoidal beat signal and a train of 1.3 ps pulses at a repetition rate of 160 GHz at 1550 nm. Using a commercially-available optical spectrum analyzer in the SHG-FROG set-up, incident pulses with energies of only 125 and 190 fJ, which correspond to the beat signal and the 1.3 ps pulse train, respectively, have been accurately characterized.
Oxidative stress, inflammation and cardiovascular disease in chronic renal failure
2008
Traditional risk factors such as hypertension, diabetes, dyslipidemia, obesity and metabolic syndrome, as well as additional nontraditional risk factors, can damage the kidney directly and by promoting intrarenal atherogenesis. Evidence indicates that increased oxidative stress and inflammation may mediate most of the effects of risk factors on the kidney. Clinical studies have demonstrated a relationship between oxidative stress and inflammatory biomarkers, and a few studies indicate an inverse correlation of oxidative stress biomarkers with estimated glomerular filtration rate (eGFR). Further, surrogate indexes of atherosclerosis such as intima-media thickness and aortic pulse wave veloci…
Periodic time-domain modulation for the electrically tunable control of optical pulse train envelope and repetition rate multiplication
2012
An electrically tunable system for the control of optical pulse sequences is proposed and demonstrated. It is based on the use of an electrooptic modulator for periodic phase modulation followed by a dispersive device to obtain the temporal Talbot effect. The proposed configuration allows for repetition rate multiplication with different multiplication factors and with the simultaneous control of the pulse train envelope by simply changing the electrical signal driving the modulator. Simulated and experimental results for an input optical pulse train of 10 GHz are shown for different multiplication factors and envelope shapes. © 2006 IEEE.
Ventricular-vascular coupling in hypertension: methodological considerations and clinical implications.
2014
The present review is addressed to analyse the complex interplay between left ventricle and arterial tree in hypertension. The different methodological approaches to the analysis of ventricular vascular coupling in the time and frequency domain are discussed. Moreover, the role of hypertension-related changes of arterial structure and function (stiffness and wave reflection) on arterial load and how ventricular-vascular coupling modulates the process of left ventricular adaptation to hypertension are analysed.The different interplay between vascular bed and left ventricle emerges as the pathophysiological basis for the development of the multiple patterns of ventricular structural adaptatio…
All-optical extinction-ratio enhancement of a 160 GHz pulse train by a saturable-absorber vertical microcavity
2006
International audience; A vertical-access passive all-optical gate has been used to improve the extinction ratio of a 160 GHz pico-second pulse train at 1555 nm. An extinction ratio enhancement of 6 dB is observed within an 8 nm bandwidth. Such a device is a promising candidate for low-cost all optical reamplication and reshaping (211) regeneration at 160 Gbits/s.
Generation of a 160-GHz transform-limited pedestal-free pulse train through multiwave mixing compression of a dual-frequency beat signal.
2002
International audience; We report the experimental generation of a 160-GHz picosecond pulse train at 1550 nm, using multiple four-wave mixing temporal compression of an initial dual-frequency beat signal in the anomalous-dispersion regime of a nonzero dispersion-shifted fiber. Complete intensity and phase characterizations of the pulse train were carried out by means of a frequency-resolved optical gating technique, showing that 1.27-ps transform-limited pedestal-free Gaussian pulses were generated.
Optical Cavity-Less 40-GHz Picosecond Pulse Generator in the Visible Wavelength Range
2019
International audience; High-repetition-rate optical frequency-comb sources emitting picosecond pulses play important roles in variousscientific researches and industrial applications. Such ultrafast pulse sources are mostly generated in opticalcavities or microresonators. By means of the wavelength-conversion techniques, it is possible to transfer thecavity-based near-IR robust and compact sources to the mid-IR or to the visible wavelength regions [1-2], forwhich there is an increasing demand, for biophotonics and other applications. Here we demonstrate the generationof high-repetition-rate picosecond pulses in the visible wavelength range by using a fully optical cavity-lessconfiguration.…
Wavelength conversion and temporal compression of a pulse train using a dispersion oscillating fiber
2014
International audience; We demonstrate the generation of a picosecond pulse train taking advantage of the cross gain occurring in a dispersion oscillating fibre. The resulting frequency-converted signal is detuned by more than 20 nm from the pump and can be temporally compressed by a factor 2 compared to the input sinusoidal pump wave.