Search results for "doppler"
showing 10 items of 637 documents
Enhanced supercontinuum generation in tapered tellurite suspended core fiber
2015
Abstract We demonstrate 400-THz (0.6–3.3 µm) bandwidth infrared supercontinuum generation in a 10 cm-long tapered tellurite suspended core fiber pumped by nJ-level 200-fs pulses from an optical parametric oscillator. The increased nonlinearity and dispersion engineering extended by the moderate reduction of the fiber core size are exploited for supercontinuum optimization on both frequency edges (i.e., 155-THz overall gain), while keeping efficient power coupling into the untapered fiber input. The remaining limitation of supercontinuum bandwidth is related to the presence of the high absorption beyond 3 µm whereas spectral broadening is expected to fully cover the glass transmission window…
Non-Contact Measurement of River Surface Velocity and Discharge Estimation with a Low-Cost Doppler Radar Sensor
2020
River discharge is an important variable to measure in order to predict droughts and flood occurrences. Once the cross-sectional geometry of the river is known, discharge can be inferred from water level and surface flow velocity measurements. Since river discharges are of particular interest during extreme weather events, when river sites cannot be safely accessed, noncontact sensing technologies are particularly appealing. To this purpose, this work proposes a prototype of a low-cost continuous wave (CW) Doppler radar sensor, which is able to monitor the surface flow velocity of rivers. The prototype is tested at two gauged sites in central Italy, along the Tiber River. The surface flow v…
Incidenza del vasospasmo e correlazione tra la neuroradiologia per immagini e l’emodinamica cerebrale
2008
Ocena zależności pomiędzy objawami klinicznymi przewlekłej niewydolności żylnej i ultrasonograficznymi cechami refluksu żylnego u chorych z żylakami …
2001
Wstęp: Celem badania było porównanie objawów klinicznych przewlekłej niewydolności żylnej ze stopniem nasilenia refluksu żylnego, stwierdzanym w badaniu ultrasonograficznym u chorych z żylakami kończyn dolnych. Materiał i metody: Badaniu poddano 50 chorych — 100 kończyn dolnych: 23 kończyny bez żylaków (w tych przypadkach żylaki występowały na drugiej kończynie), 13 kończyn z żylakami, które nie powodowały dolegliwości, 49 kończyn z żylakami, którym towarzyszył obrzęk i/lub dolegliwości bólowe, 15 kończyn z żylakami z towarzyszącymi zmianami skórnymi (z wyjątkiem owrzodzenia). Przeprowadzono ultrasonograficzną (USG Duplex-Doppler) ocenę refluksu w żyłach: udowej, podkolanowej, piszczelowej …
L'indice eco-Doppler di resistenza arteriosa parenchimale è predittivo di insufficienza renale occulta
2010
Intraoperative microvascular Doppler monitoring of blood flow within a spinal dural arteriovenous fistula: a precious surgical tool. Case report.
2001
The authors describe a case of spinal arteriovenous fistula (AVF) treated by a microvauscular Doppler–assisted surgical interruption of the arterialized vein. Microvascular Doppler monitoring represents a valid, widely available, non-invasive tool that enables identification, through flow spectrum analysis, of components of this type of vascular malformation. In this case because the location of the fistula was identified prior to opening the dura only minimally invasive surgery was required. Direct recordings of the arterialized draining vein and the nidus of the fistula demonstrated a pathological spectrum caused by the arterial supply and the disturbed venous outflow in which a high-resi…
Very narrow-bandwidth tunable infrared difference frequency generation with injection-locked dye lasers
1989
Two flashlamp pumped dye lasers of very high spectral quality are mixed in a LiIO3 crystal to generate a tunable infrared beam through the difference frequency mixing. Thanks to the injection-locking process of the pulsed dye lasers leading to a linewidth of 6 MHz with peak powers of about 10 kW, we obtain an IR beam tunable from 3.5 to 5.9 μm with a peak power of 40 W and a linewidth of 9 MHz. As an application we present a spectrum of N2O obtained by differential absorption near 1880 cm−1. The lines of thisQ-branch are Doppler limited at the working pressure (102 Pa).
ASSOCIAZIONE TRA INDICE DI RESISTENZA INTRARENALE E STIFFNESS AORTICA IN SOGGETTI CON MALATTIA RENALE CRONICA
2014
RAZIONALE. L’indice di resistenza intraparenchimale renale (IR), valutato mediante eco-color-Doppler, è stato classicamente utilizzato quale valido strumento di valutazione diagnostica e prognostica delle patologie renali. Studi recenti suggeriscono che i parametri emodinamici intrarenali, e l’IR in particolare, possano essere anche associati ad alterazioni vascolari sistemiche, nonché ad un incremento del rischio cardiovascolare. Tuttavia, dati contrastanti esistono in letteratura circa l'associazione indipendente tra IR e pulse wave velocity aortica (PWVa), indice di stiffness arteriosa, nonché espressione di danno d'organo subclinico. Scopo di questo studio è stato dunque quello di valut…
Relazione tra indice di resistenza renale e severità dell’aterosclerosi carotidea in soggetti con ipertensione arteriosa.
2014
RAZIONALE. L’indice di resistenza intraparenchimale renale (IR), valutato mediante eco-color-Doppler, è stato classicamente considerato mera espressione di resistenza vascolare distrettuale renale. Studi più recenti, tuttavia, hanno mostrato come tale indice sia anche influenzato da fattori a tergo, compliance vasale in primis, a prova di un suo possibile ruolo quale marker di alterazioni vascolari sistemiche. Diversi studi hanno dimostrato, inoltre, come lo spessore intimale (IMTc) e la placca a livello carotideo, valutati mediante ultrasonografia, siano documentati marcatori di danno d'organo subclinico nonché espressioni progressive di malattia aterosclerotica. Scopo del nostro studio è …
FOCAL LIVER LESIONS: CONTRAST-ENHANCED ULTRASOUND
2008
Contrast-enhanced ultrasound (CEUS) represents a significant breakthrough in sonography and it is being increasingly used for evaluation of focal liver lesions (FLLs). The unique feature of CEUS of non-invasively assessing in real time liver perfusion throughout the vascular phase has led to a dramatic improvement in diagnostic accuracy of US in either detection and characterization of FLLs, as well as in the guidance and evaluation of response of therapeutic procedures. Currently, CEUS is included as a part of the suggested diagnostic work-up of FLLs, resulting in a better patient management and cost-effective therapy delivering. After a brief description of the basis of different CEUS tec…