Search results for "laser"

Integration of high resolution spatial and spectral data acquisition systems to provide complementary datasets for cultural heritage applications

2010

International audience; Modern optical measuring systems are able to record objects with high spatial and spectral precision. The acquisition of spatial data is possible with resolutions of a few hundredths of a millimeter using active projection-based camera systems, while spectral data can be obtained using filter-based multispectral camera systems that can capture surface spectral reflectance with high spatial resolution. We present a methodology for combining data from these two discrete optical measuring systems by registering their individual measurements into a common geometrical frame. Furthermore, the potential for its application as a tool for the non-invasive monitoring of painti…

Resolution Characterizations of JetRIS in Mainz Using 164Dy

2022

Atoms 10(2), 57 (2022). doi:10.3390/atoms10020057

Enhancing the luminescence efficiency of silicon-nanocrystals by interaction with H+ions

2018

The emission of silicon nanocrystals (Si-NCs), synthesized by pulsed laser ablation in water, was investigated on varying the pH of the solution. These samples emit μs decaying orange photoluminescence (PL) associated with radiative recombination of quantum-confined excitons. Time-resolved spectra reveal that both the PL intensity and the lifetime increase by a factor of ∼20 when the pH decreases from 10 to 1 thus indicating that the emission quantum efficiency increases by inhibiting nonradiative decay rates. Infrared (IR) absorption and electron paramagnetic resonance (EPR) experiments allow addressing the origin of defects on which the excitons nonradiatively recombine. The linear correl…

Temporal Denoising of Kinect Depth Data

2012

The release of the Microsoft Kinect has attracted the attention of researchers in a variety of computer science domains. Even though this device is still relatively new, its recent applications have shown some promising results in terms of replacing current conventional methods like the stereo-camera for robotics navigation, multi-camera system for motion detection and laser scanner for 3D reconstruction. While most work around the Kinect is on how to take full advantage of its capabilities, so far only a few studies have been carried out on the limitations of this device and fewer that provide solutions to enhance the precision of its measurements. In this paper, we review and analyse curr…

Preliminary study about the efficiency of diode laser compared with retraction cords used for exposing the finishing lines of dental abutments before…

2016

Gingival displacement using diode laser or retraction cords: A comparative clinical study.

2018

PURPOSE: To compare two systems used for conditioning the gingival sulcus and exposing the finish line before the final impression for a fixed denture: retraction cords and diode laser. METHODS: All subjects participating in the study had healthy gingival and periodontal status before intervention for fixed prosthesis. 74 abutments for complete crown restoration were randomly divided into two groups for displacing the gingival sulcus before the final impression: gingival retraction cords (RC) and diode laser (DL). The height of the clinical crowns was measured by a blinded examiner in three points of the buccal surface (mesial, midline and distal) at four different times: after tooth prepar…

Geomatic applications tourban park in palermo

2015

Over the last few years topographical techniques have developed an exponential trend towards simplifying and speeding, both survey operations and analysis of data collected reaching at the same time ever higher levels of accuracy. Among the technologies that are increasingly taking the field in this context is part of the Mobile Mapping System (MMS) that, on any mobile platform, combines sensors and measurement systems designed to provide a 3D position of the platform and, at the same time, capable to acquire geographic data without the aid of control points on the ground. The study reported concerns the verification of the reliability metrics and a qualitative MMS in order to evaluate its …

Ruolo della fotocoagulazione laser nell’edema maculare diabetico: benefici e limiti

2012

2016

The photochemistry of benzophenone, a paradigmatic organic molecule for photosensitization, was investigated by means of surface-hopping ab initio molecular dynamics. Different mechanisms were found to be relevant within the first 600 fs after excitation; the long-debated direct (S1 → T1) and indirect (S1 → T2 → T1) mechanisms for population of the low-lying triplet state are both possible, with the latter being prevalent. Moreover, we established the existence of a kinetic equilibrium between the two triplet states, never observed before. This fact implies that a significant fraction of the overall population resides in T2, eventually allowing one to revisit the usual spectroscopic assignm…

Lifetime measurements of the 3D3/2 and 3D5/2 metastable states in CaII

1993

The lifetime of the metastable 3D3/2 and 3D5/2 states of Ca+ ions is determined in a r.f. ion trap by laser excitation of this levels and subsequent time delayed probing of the state population by a second laser. In a buffer gas atmosphere of about 10−5−10−6 mbar of He we observe quenching to the ground state and strong finestructure mixing of the two D-states. This mixing allowes only the determination of the combined lifetime. Our result of τ(3D)=1.24(39) s is in good agreement with theoretical calculations.