Search results for "laser"
showing 10 items of 3161 documents
Ethane-Bridged Zinc-Porphyrin Dimers in Langmuir-Shäfer Thin Films: Structural and Spectroscopic Properties
2006
This work reports on the structural and spectroscopic properties of ethane-bridged Zn porphyrin dimers (1) in Langmuir-Scha¨fer (LS) thin films by combining scanning force microscopy (SFM) with film balance, UV-vis absorption, fluorescence, and nanosecond laser flash photolysis measurements. Results show that depending on the surface pressure the Langmuir films of pure 1 can be arranged in two different condensed phases, whereas SFM of the LS films shows characteristic fractal networks constituted by nanoscopic aggregates. The spectral findings agree with a picture in which 1 is apparently present in the anti conformation but aggregated in a sort of H-type structure whose optical features r…
Lanthanide-doped Y3Ga5O12 garnets for nanoheating and nanothermometry in the first biological window
2018
Abstract Absorption and luminescence spectra in the first biological window of Nd3+ single-doped and Er3+-Yb3+ co-doped Y3Ga5O12 nano-garnets have been studied to evaluate their potential use as simultaneous optical nanoheaters and nanothermometers in biomedicine. Nd3+-doped nano-garnets uses the 808 nm laser radiation, resonant with the largest absorption peak of the 4I9/2 → 4F5/2 transition, for both heating the nanoparticle and populating the 4F3/2 emitting level. Changes in the relative intensities of different emission peaks between Stark levels of the 4F3/2 (R1,2)→4I9/2 (Z1-5) transition can be directly related to the temperature of the nano-garnet. On the other hand, the Yb3+/Er3+com…
Influence of Ce codoping and H2 pre-loading on Er/Yb-doped fiber: Radiation response characterized by Confocal Micro-Luminescence
2011
International audience; Confocal microscopy luminescence measurements were applied to study the X-ray radiation response of Er/Yb-doped optical fibers in connection with H2 pre-loading and with the addition of another lanthanide element (Cerium) in the core composition. Laser excitations at 488 nm and 325 nm allow deriving the emission and absorption pattern of Er3+, the latter derived from the dips appearing in a wide luminescence band related to defects in silica. We found that the luminescence spectrum of the X-irradiated Er/Yb-doped core fiber evidences an increase in the emission intensity around 520 and 660 nm; in contrast, no changes are induced by radiation neither after H2 pre-load…
Laser Triangulation 3D Point Cloud Sensor with Long Range and Large Field of View
2020
This paper presents a point cloud sensor design based on laser triangulation. Both the camera axis and the laser axis are rotating, making it possible to scan on short and long range in high resolution. A third axis moves the laser and camera into a new plane. The design is tested on a working prototype. To the authors knowledge a similar design has not been presented before.
Acute tissue damage induced by monopolar microelectrodes and radiofrequency in vocal cords after transoral cordectomy
2021
Abstract Introduction: In 2006 and 2009, we reported the levels of acute and chronic tissue damage after cordectomy associated with use of the microlectrodes using high frequency energy. In 2010, we shifted to radiofrequency rather than high frequency electrogenerators. Objective: The aim of this study is to evaluate acute tissue damage in the larynx after cordectomy using microelectrodes coupled to a radiofrequencygenerator. Methods: We studied 22 patients with a stage T1 glottic squamous cell carcinoma. The patients were randomly assigned to the two operating mode: cutting or coagulation (11 patients each mode). The strength of the study is that there are no previous studies on the effect…
Treatment of bilateral vocal cord paralysis following permanent recurrent laryngeal nerve injury.
2012
Bilateral vocal cord paralysis is a serious illness requiring emergency intervention to resolve the potentially life-threatening respiratory distress. Several surgical procedures were proposed to help improve the airway and to eliminate the tracheostoma in those patients with permanent paralysis. All the procedures have their own advantages and disadvantages. We conducted a retrospective study of 30 patients affected by bilateral vocal cord paralysis following total thyroidectomy. All the patients underwent total thyroidectomy for benign thyroid pathology. In 26 patients (86.6%), cord paralysis occurred during the perioperative stage; and in the remaining 4 cases (13.3%), it occurred within…
Fast and green: Sustainable rapid-prototyping of microfluidic chips on polylactic acid substrates
2018
This paper reports novel ways to bond bio-based polylactic acid (PLA) substrates for the production of sustainable, single-use, microfluidic components. A laser-based, fast (minutes) fabrication process for multi-layer microfluidic devices in PLA was reported recently but in that report, demonstrator devices were bonded with adhesive tape, which significantly reduced the devices transparency. In this paper, we propose two novel ways to bond PLA substrates, which alleviate the need for adhesives, and enable optimal device transparency.
Fabrication and electro-optical characterization of Ruthenium-based Dye-Sensitized Solar Cells
2015
In this paper, we measure the main photoelectrical parameters of Dye Sensitized Solar Cells (DSSCs) based on ruthenium complexes at different irradiance levels, incident wavelengths, temperatures and hours of light soaking
Experimental characterization of Ruthenium-based Dye Sensitized Solar Cells and study of light-soaking effect impact on performance
2016
In this paper, we present an experimental investigation on the performance of Ruthenium-based Dye Sensitized Solar Cells (DSSCs) at different irradiance levels, incident wavelengths and hours of illumination. In particular, the measurements have been aimed at studying the performance variation due to light soaking effect since this phenomenon has noteworthy practical implications, such as stability tests of DSSCs. Our results show that the short circuit current density, the open circuit voltage and the conversion efficiency η increase with the hours of light soaking. Finally, the observed phenomenon is reversible, and thus the performance decreases again when the cell is kept in the dark.
Characterization of thin film CIG(S,SE)2 submodules using solar simulator and laser beam induced current techniques (Versione estesa)
2015
In this work, the electrical and optical characterization of CIG(S, Se)2 sub-modules using both a solar simulator equipment and the Laser Beam Induced Current (LBIC) technique is presented. By using the solar simulator and a proper set-up, the electrical parameters of the modules at varying irradiance and temperatures are determined. In addition, the LBIC measurements are carried out to analyze the 2D photocurrent uniformity of the modules at two different wavelengths. Dispersion values of extracted parameters can be very useful for practically tuning the modelling stage at device/module level.