Search results for "LASER"
showing 10 items of 3161 documents
Solid-state-biased coherent detection of ultra-broadband terahertz pulses
2017
Significant progress in nonlinear and ultrafast optics has recently opened new and exciting opportunities for terahertz (THz) science and technology, which require the development of reliable THz sources, detectors, and supporting devices. In this work, we demonstrate the first solid-state technique for the coherent detection of ultra-broadband THz pulses (0.1-10 THz), relying on the electric-field-induced second-harmonic generation in a thin layer of ultraviolet fused silica. The proposed CMOS-compatible devices, which can be realized with standard microfabrication techniques, allow us to perform ultra-broadband detection with a high dynamic range by employing probe laser powers and bias v…
Clinical and radiological course in apicoectomies with the Erbium : YAG LASER
2007
A study is made of the efficacy of the Erbium: YAG laser in granulomatous periapical lesions, based on clinical and radiographic controls. The study comprised a series of 45 patients amenable to periapical surgical treatment of incisors, canines and premolars. A conventional surgical technique was used, with silver amalgam retrograde filling and irradiation of the bone defect and remnant root cement with the Erbium: YAG laser. Clinical and radiographic controls were made during 24 months, assessing the absence of symptoms and the presence of pain, swelling or fistula and ossification of the lesions, respectively. The clinical course proved asymptomatic in 95.5% of the cases. As regards remo…
Effect of laser radiation upon heat and mass transfer in two-component elastic semitransparent layer
2004
Abstract In present paper the effect of the correlation between spectral radiative characteristics of different lasers and absorptive characteristics of laser irradiated two-component elastic semitransparent material upon coupled thermal, diffusive and elastic processes in the layer is examined. Irradiated material is supposed to consist of elastic matrix and gaseous admixture. Investigations are carried out within the model applied early to the study of mentioned coupled processes in the layer subjected to thermal infrared radiation. Calculations were carried out for four different infrared lasers. Peculiarities of heat and admixture mass transfer caused by laser irradiation are establishe…
Integrated analytical methodologies for the study of corrosion processes in archaeological bronzes
2011
Abstract The investigations on structure and micro-chemical composition of archaeological metal alloys are needed in archaeometry. The aim of this study is devoted both to acquire information about their provenance and production technology, and to improve our understanding about the corrosion processes. In this paper we present the study of the corrosion phenomena of bronze samples, laboratory-made according to binary, ternary and quaternary alloys typical of Roman archaeometallurgical production through an integrated methodology based on the use of non or micro invasive physical techniques. Among the analysed samples, two were artificially aged through burial in the archaeological site of…
Hemodynamic Parameters Change Earlier Than Tissue Oxygen Tension in Hemorrhage
2010
BACKGROUND: Untreated hypovolemia results in impaired outcome. This study tests our hypothesis whether general hemodynamic parameters detect acute blood loss earlier than monitoring parameters of regional tissue beds. MATERIALS AND METHODS: Eight pigs (23-25 kg) were anesthetized and mechanically ventilated. A pulmonary artery catheter and an arterial catheter were inserted. Tissue oxygen tension was measured with Clark-type electrodes in the jejunal and colonic wall, in the liver, and subcutaneously. Jejunal microcirculation was assessed by laser Doppler flowmetry (LDF). Intravascular volume was optimized using difference in pulse pressure (dPP) to keep dPP below 13%. Sixty minutes after p…
Monochorionic twin pregnancy: screening, pathogenesis of complications and management in the era of microinvasive fetal surgery
2010
Objective The management of monochorionic (MC) twin pregnancies varies in different medical centers. This paper compares screening methods to predict the complications of the MC twin pregnancy and different treatment methods. Methods We performed a literature search without language restriction in Cochrane library and PubMed (1970-2009). Case series and cohort screening studies, pathogenesis and management of complications of MC pregnancy were included. Results Elevated risk for intrauterine fetal death (IUFD) and twin-to-twin transfusion syndrome (TTTS) can be detected sonographically. Monitoring of MC pregnancies at increased risk and regular training sessions for the operating team combi…
Spatial beam self-cleaning in multimode fibres
2017
Multimode optical fibres are enjoying a renewed attention, boosted by the urgent need to overcome the current capacity crunch of single-mode fibre systems and by recent advances in multimode complex nonlinear optics [1-13]. In this work, we demonstrate that standard multimode fibres can be used as ultrafast all-optical tool for transverse beam manipulation of high power laser pulses. Our experimental data show that the Kerr effect in a graded-index multimode fibre is the driving mechanism for overcoming speckle distortions, leading to a somewhat counter-intuitive effect resulting in a spatially clean output beam robust against fibre bending. Our observations demonstrate that nonlinear beam …
The Technologies of Architectural Survey: A New Comparison Based on the Tower of Sotillo de la Ribera, Burgos
2017
The paper offers an original research about the analysis and the comparison of different techniques of survey concerning the architectural field – image-based and range-based – throughout the development of the theory of errors in order to evaluate reliability and precision of the results. In particular, this analysis will be focused on the tower of the parochial Church of Santa Águeda, a building located in the small village of Sotillo de la Ribera, within the province of Burgos (Spain). The first part of this work, therefore, has been submitted to the implementation of different methodologies, from the direct survey used as a basis, to the procedure to represent graphically the results (e…
I Telamoni del Tempio di Zeus ad Agrigento: rilievi, disegni e ricostruzioni
2013
Oggetto dello studio qui presentato è la ricostruzione di un intercolumnio del fronte esterno del Tempio di Zeus ad Agrigento, basata sul rilievo del Telamone oggi custodito presso il Museo Archeologico, sugli studi e i numerosi saggi di ricostruzione proposti dagli studiosi dal XVIII secolo fino alla metà dello scorso secolo e sulla analisi strutturale del Telamone ricostruito nel Museo. The drawings of the telamones, the giant statues placed the front of the Temple of Zeus in the archaeological area of Agrigento, have fascinated some of the most famous neoclassical architects in Europe. The virtual reconstruction of one intercolumnial of the Temple, based both on the range-based survey of…
Nanoring as logic gate and memory mass device
2015
We study the application of one nanoring driven by a laser field in different states of polarization in logic circuits. In particular we show that assigning boolean values to different state of the incident laser field and to the emitted signals, we can create logic gates such as OR, XOR and AND. we also show the possibility to make logic circuits such as half-adder and full-adder using one and two nanoring respectively. Using two nanorings we made tho Toffoli gate. Finally we use the final angular momentum acquired by the eelctron to store information and hence show the possibility to use and array of nanorings as a mass device.