Search results for "Time of Flight"
showing 10 items of 114 documents
Space Charge and Carrier Trapping Effects on the Transient Photocurrents of Organic Materials Using the Time-of-Flight Technique
2007
We apply the time-of-flight (TOF) technique to study space charge and carrier trapping effects in the organic materials N,N'-diphenyl-N,N'-bis(3- methylphenyl)-1,1-biphenyl-4,4'-diamine (TPD) and tris(8-hydroxyquinolato) aluminum (Alq3). This is carried out by changing the applied electric field, the laser pulse intensity, and the repetition rate together with environmental conditions in air or in vacuum. We report for the first time, to the best of our knowledge, a clearly nondispersive electron transport in TPD due to the absence of deep traps. Conversely, Alq3 exhibits a dispersive electron transport. However, this can be partially recovered by leaving the sample in high vacuum for sever…
Compressive sensing for direct time of flight estimation in ultrasound-based NDT
2017
This paper presents an approach for estimation of ultrasonic time-of-flight (TOF) within a Non Destructive Testing (NDT) and Structural Health Monitoring (SHM) context. The presented method leverages recent advances in the field of Compressive Sensing (CS), which makes use of sparsity in a transform domain of a signal in order to reduce the number of samples required to store it. CS achieves this through a two key ideas: random matrix projections, and l1-penalised linear regression. In this case, sparsity arises from the observation that in a pulse-echo ultrasound test, the number of echoes is relatively small compared to the number of measurement points in a waveform. This sparsity is evid…
Sensitive Screening of New Psychoactive Substances in Serum Using Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry.
2021
Abstract Analysis of new psychoactive substances (NPS) still poses a challenge for many institutions due to the number of available substances and the constantly changing drug market. Both new and well-known substances keep appearing and disappearing on the market, making it hard to adapt analytical methods in a timely manner. In this study we developed a qualitative screening approach for serum samples by means of liquid chromatography--quadrupole time-of-flight mass spectrometry. Samples were measured in data-dependent auto tandem mass spectrometry mode and identified by fragment spectra comparison, retention time and accurate mass. Approximately 500 NPS, including 195 synthetic cannabino…
The study of neutron-rich nuclei production in the region of the closed shell N=126 in the multi-nucleon transfer reaction 136Xe+208Pb
2015
Expérience LNL/PRISMA; International audience; The unexplored area of heavy neutron rich nuclei is extremely important for nuclearastrophysics investigations and, in particular, for the understanding of the r-process ofastrophysical nucleogenesis. For the production of heavy neutron rich nuclei located along theneutron closed shell N=126 (probably the last "waiting point" in the r-process of nucleosynthesis)the low-energy multi-nucleon transfer reaction 136Xe+208Pb at Elab=870MeV was explored.Due to the stabilizing eect of the closed neutron shells in both nuclei, N=82 and N=126, andthe rather favorable proton transfer from lead to xenon, the light fragments formed in this processare well b…
Hybrid Observer for Indoor Localization with Random Time-of-Arrival Measurments
2018
In this work an indoor position estimation algorithm will be proposed. The position will be measured by means of a sensor network composed by fixed beacons placed on the indoor environment and a mobile beacon mounted on the object to be tracked. The mobile beacon communicates with all the fixed beacons by means of ultra wide-band signals, and the distance between them is computed by means of time of flight techniques. Moreover, inertial measurements will be used when the position measurements are not available. Two main problems will be considered in the proposed architecture: the fact that the beacons work with a lower update rate than the IMU, and that the mobile beacon can comunicate wit…
TOF LiDAR with SiPM technology
2016
LiDAR (Light Detection And Ranging) systems measures the distance from the sensor to the target by determining the time between the release of the laser pulse to the receiving of the backscattered pulse. The interest in LiDAR technology has exploded in recent years since the applications are numerous. Here, we would highlight the Advanced Driver Assistance Systems (ADAS) and for rendezvous & docking operations between spacecraft. We built two LiDAR systems differing for the detector: a Silicon Photomultiplier (SiPM) and an Avalanche Photodiode (APD). The advantages of the SiPM approach has been extensively discussed in [1]. The comparison between these systems has been performed in terms of…
Comparison in terms of TOF measurements between APD and SiPM for LiDAR applications
2016
We present an experimental comparison of two LiDAR systems, employing the SiPM and the APD as photodetectors, in terms of TOF measurements differing for the distance of the target and at different intensities of ambient light. The use of the APD represents the conventional approach, while the implementation of the SiPM is innovative. The performed measurements achieved very promising results, thus demonstrating the effectiveness of our LiDAR based on SiPM.
Multinuclear magnetic resonance, electrospray ionization time-of-flight mass spectral and molecular modelling characterization of lithocholic acid am…
2003
1H, 13C and 15N NMR and electrospray ionization time-of-flight mass spectrometric characterizations of five lithocholate esters of piperazine diamides are described. Two of them are cholaphane-type cyclic structures esterified with 2,2′-bipyridine-4,4 ′ - and pyridine-2,6-dicarboxylic acid and the other three esters are open structures comprising two or four lithocholyl residues. The conformational preferences of the dimeric congeners were examined by using molecular modelling and variable-temperature 1H NMR techniques. Copyright © 2003 John Wiley & Sons, Ltd.
Multiplicity dependence of light (anti-)nuclei production in p–Pb collisions at sNN=5.02 TeV
2020
The measurement of the deuteron and anti- deuteron production in the rapidity range −1 < y < 0 as a function of transverse momentum and event multiplicity in p–Pb collisions at √sNN= 5.02 TeV is presented. (Anti-)deuterons are identified via their specific energy loss dE/dxand via their time-of-flight. Their production in p–Pb collisions is compared to pp and Pb–Pb collisions and is discussed within the context of thermal and coalescence models. The ratio of integrated yields of deuterons to protons (d/p) shows a significant increase as a function of the charged-particle multiplicity of the event starting from values similar to those observed in pp collisions at low multiplicities and appro…
A new method for Poisson’s ratio measurement with time-of-flight technique: application to the preliminary design of smart composite structures
2019
International audience; Smart composite structures, which are able to modify their mechanical properties with respect to their environment (e.g. active vibration control), to interact with other structures (e.g. mechatronic) or with human beings (e.g. Human-Machine Interaction), are widely used in the modern industrial fields (e.g. aerospace), due to the intensification of the operational dynamic environment and an increase of durability requirements from the customers. Conventionally, the piezoelectric transducers are glued on the surface of the structure and the power and control electronics are away. To protect the transducer elements and their connections and develop some industrially p…