Bibliographies thématiques / Lasers à fente

Littérature scientifique sur le sujet « Lasers à fente »

Auteur : Grafiati
Publié le 18 mai 2024

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Articles de revues sur le sujet "Lasers à fente"

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Yuliang Zhou, Yuliang Zhou, Zhan Sui Zhan Sui, Yuanchao Geng Yuanchao Geng, Lixin Xu Lixin Xu et Hai Ming Hai Ming. « Using fence pulses to suppress stimulated Raman scattering effect in laser–plasma interaction ». Chinese Optics Letters 12, no 9 (2014) : 092902–92905. http://dx.doi.org/10.3788/col201412.092902.

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Pakulski, G., G. Knight, S. R. Das, T. Jones, C. Blaauw et J. K. White. « Semi-insulating buried heterostructure laser with PN fence ». Electronics Letters 38, no 25 (2002) : 1680. http://dx.doi.org/10.1049/el:20021156.

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Yang, Chuan Sen, Li Xin Cao, Ning Chen, Wei Yong Li, Li Hua Liu et Ying Zi Zhang. « Preparation and Transport Properties of Superconducting Fete Thin Film ». Advanced Materials Research 629 (décembre 2012) : 236–39. http://dx.doi.org/10.4028/www.scientific.net/amr.629.236.

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We successfully deposited the purely c-axis oriented Fete thin film, which shows superconducting transition in electrical resistivity about 12 K, by using pulsed laser deposition method. The electrical transport measurements of the thin film are studied with magnetic fields up to 14.0 T. thermally activated energy is analyzed using simple conventional Arrhenius relation and more precise relation who is closer to experimental results. Besides, the upper critical magnetic field and the vortex glass transition temperatures for the Fete thin film are studied.
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Flesch, T. K., J. D. Wilson et L. A. Harper. « Deducing Ground-to-Air Emissions from Observed Trace Gas Concentrations : A Field Trial with Wind Disturbance ». Journal of Applied Meteorology 44, no 4 (1 avril 2005) : 475–84. http://dx.doi.org/10.1175/jam2214.1.

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Abstract Inverse-dispersion techniques allow inference of a gas emission rate Q from measured air concentration. In “ideal surface layer problems,” where Monin–Obukhov similarity theory (MOST) describes the winds transporting the gas, the application of the technique can be straightforward. This study examines the accuracy of an ideal MOST-based inference, but in a nonideal setting. From a 6 m × 6 m synthetic area source surrounded by a 20 m × 20 m square border of a windbreak fence (1.25 m tall), Q is estimated. Open-path lasers gave line-averaged concentration CL at positions downwind of the source, and an idealized backward Lagrangian stochastic (bLS) dispersion model was used to infer QbLS. Despite the disturbance of the mean wind and turbulence caused by the fence, the QbLS estimates were accurate when ambient winds (measured upwind of the plot) were assumed in the bLS model. In the worst cases, with CL measured adjacent to a plot fence, QbLS overestimated Q by an average of 50%. However, if these near-fence locations are eliminated, QbLS averaged within 2% of the true Q over 61 fifteen-minute observations (with a standard deviation σQ/Q = 0.20). Poorer accuracy occurred when in-plot wind measurements were used in the bLS model. The results show that when an inverse-dispersion technique is applied to disturbed flows without accounting for the disturbance, the outcome may still be of acceptable accuracy if judgment is applied in the placement of the concentration detector.
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Dowman, Emma, Frances Wall, Peter J. Treloar et Andrew H. Rankin. « Rare-earth mobility as a result of multiple phases of fluid activity in fenite around the Chilwa Island Carbonatite, Malawi ». Mineralogical Magazine 81, no 6 (décembre 2017) : 1367–95. http://dx.doi.org/10.1180/minmag.2017.081.007.

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AbstractCarbonatites are enriched in critical raw materials such as the rare-earth elements (REE), niobium, fluorspar and phosphate. A better understanding of their fluid regimes will improve our knowledge of how to target and exploit economic deposits. This study shows that multiple fluid phases penetrated the surrounding fenite aureole during carbonatite emplacement at Chilwa Island, Malawi. The first alkaline fluids formed the main fenite assemblage and later microscopic vein networks contain the minerals of potential economic interest such as pyrochlore in high-grade fenite and rare-earth minerals throughout the aureole. Seventeen samples of fenite rock from the metasomatic aureole around the Chilwa Island carbonatite complex were chosen for study. In addition to the main fenite assemblage of feldspar and aegirine ± arfvedsonite, riebeckite and richterite, the fenite contains micro-mineral assemblages including apatite, ilmenite, rutile, magnetite, zircon, rare-earth minerals and pyrochlore in vein networks. Petrography using a scanning electron microscope in energy-dispersive spectroscopy mode showed that the rare-earth minerals (monazite, bastnäsite and parisite) formed later than the fenite feldspar, aegirine and apatite and provide evidence ofREEmobility into all grades of fenite. Fenite apatite has a distinct negative Eu anomaly (determined by laser ablation inductively coupled plasma mass spectrometry) that is rare in carbonatite-associated rocks and interpreted as related to pre-crystallization of plagioclase and co-crystallization with K-feldspar in the fenite. The fenite minerals have consistently higher midREE/lightREEratios (La/Sm ≈ 1.3 monazite, ≈ 1.9 bastnäsite, ≈ 1.2 parisite) than their counterparts in the carbonatites (La/Sm ≈ 2.5 monazite, ≈ 4.2 bastnäsite, ≈ 3.4 parisite). Quartz in the low- and medium-grade fenite hosts fluid inclusions, typically a few micrometres in diameter, secondary and extremely heterogeneous. Single phase, 2- and 3-phase, single solid and multi solid-bearing examples are present, with 2-phase the most abundant. Calcite, nahcolite, burbankite and baryte were found in the inclusions. Decrepitation of inclusions occurred at ∼200°C before homogenization but melting-temperature data indicate that the inclusions contain relatively pure CO2. A minimum salinity of ∼24 wt.% NaCl equivalent was determined. Among the trace elements in whole-rock analyses, enrichment in Ba, Mo, Nb, Pb, Sr, Th and Y and depletion in Co, Hf and V are common to carbonatite and fenite but enrichment in carbonatitic type elements (Ba, Nb, Sr, Th, YandREE) generally increases towards the inner parts of the aureole. A schematic model contains multiple fluid events, related to first and second boiling of the magma, accompanying intrusion of the carbonatites at Chilwa Island, each contributing to the mineralogy and chemistry of the fenite. The presence of distinct rare-earth mineral microassemblages in fenite at some distance from carbonatite could be developed as an exploration indicator ofREEenrichment.
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Shajid Pyari, Muhzina, Kata Vékony, Stefania Uccheddu et Péter Pongrácz. « Companion Cats Show No Effect of Trial-and-Error Learning Compared to Dogs in a Transparent-Obstacle Detour Task ». Animals 13, no 1 (21 décembre 2022) : 32. http://dx.doi.org/10.3390/ani13010032.

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We tested companion cats and dogs in similar indoor conditions using identical procedures in the classic detour task around a V-shaped transparent wire-mesh fence. Besides the control group, we used two types of laser light-pointing demonstration (moving around the fence, or pointing straight at the reward). We found that dogs reached the food reward faster than cats; across consecutive trials, only the dogs showed improvement in their speed and dogs continued to use the same side for detouring after a preceding successful attempt, while cats chose the side for detouring irrespective of their previous successful trials. In addition, ‘demonstrating’ a detour with the laser did not influence the speed or direction of the detour of the subjects; and dogs looked back to their owner more frequently than the cats did. We discuss the possibility that for dogs, detouring along a transparent obstacle represents a more problematic task than for cats; therefore, dogs strongly rely on their previous experiences. This is the first time that cats were successfully tested in this detour paradigm in direct comparison with dogs. The results are relevant from the aspect of testing cognitive performance in companion cats, which are known to be notoriously reluctant to engage with novel experimental situations.
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Tropea, C. D., et R. Gackstatter. « The Flow Over Two-Dimensional Surface-Mounted Obstacles at Low Reynolds Numbers ». Journal of Fluids Engineering 107, no 4 (1 décembre 1985) : 489–94. http://dx.doi.org/10.1115/1.3242518.

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The flow over a fence and a block mounted in a fully developed channel flow is experimentally investigated as a function of the Reynolds number, blockage ratio and length-to-height ratio using a laser-Doppler-anemometer. The information obtained includes the location and size of the primary and secondary recirculation zones, and profiles of the mean streamwise velocity component. The experiments were carried out in a channel for a Reynolds number in the range 150 < ReH < 4500. Comparisons are drawn between the obstacle flow and the backward-facing step flow.
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Gilbreath, G. Charmaine, Paul W. Schumacher, Mark A. Davis, Edward D. Lydick et John M. Anderson. « Evaluation of the Naval Space Surveillance Fence Performance Using Satellite Laser Ranging ». Journal of Guidance, Control, and Dynamics 22, no 1 (janvier 1999) : 149–55. http://dx.doi.org/10.2514/2.4361.

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Sako, Y., et A. Kusumi. « Barriers for lateral diffusion of transferrin receptor in the plasma membrane as characterized by receptor dragging by laser tweezers : fence versus tether. » Journal of Cell Biology 129, no 6 (15 juin 1995) : 1559–74. http://dx.doi.org/10.1083/jcb.129.6.1559.

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Our previous results indicated that the plasma membrane of cultured normal rat kidney fibroblastic cell is compartmentalized for diffusion of receptor molecules, and that long-range diffusion is the result of successive intercompartmental jumps (Sako, Y. and Kusumi, A. 1994. J. Cell Biol. 125:1251-1264). In the present study, we characterized the properties of intercompartmental boundaries by tagging transferrin receptor (TR) with either 210-nm-phi latex or 40-nm-phi colloidal gold particles, and by dragging the particle-TR complexes laterally along the plasma membrane using laser tweezers. Approximately 90% of the TR-particle complexes showed confined-type diffusion with a microscopic diffusion coefficient (Dmicro) of approximately 10(-9) cm2/s and could be dragged past the intercompartmental boundaries in their path by laser tweezers at a trapping force of 0.25 pN for gold-tagged TR and 0.8 pN for latex-tagged TR. At lower dragging forces between 0.05 and 0.1 pN, particle-TR complexes tended to escape from the laser trap at the boundaries, and such escape occurred in both the forward and backward directions of dragging. The average distance dragged was half of the confined distance of TR, which further indicates that particle-TR complexes escape at the compartment boundaries. Since variation in the particle size (40 and 210 nm, the particles are on the extracellular surface of the plasma membrane) hardly affects the diffusion rate and behavior of the particle-TR complexes at the compartment boundaries, and since treatment with cytochalasin D or vinblastin affects the movements of TR (Sako and Kusumi as cited above), argument has been advanced that the boundaries are present in the cytoplasmic domain. Rebound of the particle-TR complexes when they escape from the laser tweezers at the compartment boundaries suggests that the boundaries are elastic structures. These results are consistent with the proposal that the compartment boundaries consist of membrane skeleton or a membrane-associated part of the cytoskeleton (membrane skeleton fence model). Approximately 10% of TR exhibited slower diffusion (Dmicro approximately 10(-10)-10(-11) cm2/s) and binding to elastic structures.
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Suman, Preetam, Deepak Kumar Singh, Fahad R. Albogamy et Mohammad Shibee. « Harnessing the Power of Sensors and Machine Learning to Design Smart Fence to Protect Farmlands ». Electronics 10, no 24 (13 décembre 2021) : 3094. http://dx.doi.org/10.3390/electronics10243094.

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Agriculture and animals are two crucial factors for ecological balance. Human–wildlife conflict is increasing day-by-day due to crop damage and livestock depredation by wild animals, causing local farmer’s economic loss resulting in the deepening of poverty. Techniques are needed to stop the crop damage caused by animals. The most prominent technique used to protect crops from animals is fencing, but somehow, it is not a full-proof solution. Most fencing techniques are harmful to animals. Thousands of animals die due to the side effects of fencing techniques, such as electrocution. This paper introduces a virtual fence to solve these issues. The proposed virtual fence is invisible to everyone, because it is an optical fiber sensor cable, which is laid 12-inches-deep in soil. A laser light is used at the start of the fiber sensor cable, and a detector detects at the end of the cable. The technique is based on the reflection of light inside the fiber optic cable. The interferometric technique is used to predict the changes in the pattern of the laser light. The fiber cable sensors are connected to a microprocessor, which can predict the intrusion of any animal. The use of machine learning techniques to pattern detection makes this technique highly efficient. The machine learning algorithms developed for the identification of animals can also classify the animal. The paper proposes an economical and feasible machine-learning-based solution to save crops from animals and to save animals from dangerous fencing. The description of the complete setup of optical fiber sensors, methodology, and machine learning algorithms are covered in this paper. This concept was implemented and regressive tests were carried out. Tests were performed on the data, which were not used for training purposes. Sets of people (50 people in each set) were randomly moved into the fiber optic cable sensor in order to test the effectiveness of the detection. There have been very few instances where the algorithm has been unable to categorize the detections into different animal classes. Three datasets were tested for configuration effectiveness. The complete setup was also tested in a zoo to test the identification of elephants and tigers. The efficiency of identification is 94% for human, 80% for tiger, and 75% for elephant.
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Thèses sur le sujet "Lasers à fente"

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Oksenhendler, Thomas. « Mesures et contrôles temporels dans le domaine des lasers ultrabrefs ». Phd thesis, Ecole Polytechnique X, 2004. http://pastel.archives-ouvertes.fr/pastel-00001347.

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Cette thèse présente le développement d'un système de balayage de caméra à balayage de fente parfaitement synchronisé avec un laser impulsionnel femtoseconde. Cette application des photoconducteurs rapides ("commutateurs Auston") haute tension, permet d'obtenir des résolutions de caméra à balayage de fente subpicoseconde en mode d'accumulation d'images, avec des lasers d'énergie quelques centaines de microJoules par impulsion. Deux autres applications de ces photoconducteurs haute tension sont étudiées : - La commutation optique par une cellule de Pockels ultra-rapide de temps de montée inférieure à 100ps ayant une gigue temporelle inférieure à 2ps. - La stabilisation en énergie des impulsions laser ultrabrèves, coup par coup, à l'aide d'une cellule de Pockels commandée par un photoconducteur. Le photoconducteur (commandé en avance par une impulsion extraite de l'impulsion principale) commande la cellule de Pockels à diminuer les fluctuations. Une première expérience montre une amélioration d'un ordre de grandeur (de 7% à 0.7%). Parallèlement, une application du filtre acousto-optique dispersif programmable (Dazzler TM) à la mesure de la phase spectrale des impulsions femtosecondes est présentée. Les méthodes de mesures temporelles résultant d'un filtrage linéaire suivi d'une détection non linéaire, il est possible de réaliser la fonction de filtrage linéaire par le Dazzler TM remplaçant le montage optique souvent complexe. Il a été ainsi réalisé expérimentalement pour la première fois des mesures d'autocorrélation en bande de base et d'interférométrie spectrale à décalage par transformée de Fourier (Time-domain SPIDER).
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Fordyce, Jordan. « Single-mode interband cascade lasers for petrochemical process monitoring ». Electronic Thesis or Diss., Université de Montpellier (2022-....), 2023. http://www.theses.fr/2023UMONS070.

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Les lasers à cascade interbandes (ICL) fournissent des sources pour la gamme spectrale du moyen infrarouge compris entre 3 et 6 µm particulièrement efficaces en termes de consommation d’énergie. Cette gamme spectrale est particulièrement intéressante pour la détection des gaz impliqués dans l’industrie pétrochimique, car des gaz tels que le méthane, l'éthane et le dioxyde de carbone présentent une forte absorption dans cette gamme de longueur d’onde. L'identification correcte d'un gaz présent dans un échantillon nécessite des lasers avec une émission monomode et une certaine accordabilité en longueur d’onde. L'amélioration de cette plage de réglage possible avec une source laser offre de nouvelles opportunités dans des applications liées à la spectroscopie. Une alternative à ce qui est actuellement disponible dans le commerce peut être réalisée grâce à l'utilisation de guides d'ondes à fente, qui peuvent être fabriqués en utilisant de la photolithographie conventionnelle, réduisant ainsi le coût de fabrication.Deux nouveaux types d'ICL ont été conçus, fabriqués, et étudiés dans le cadre de cette thèse : un ICL à fentes à section unique et un ICL à fentes multiples accordé par Vernier (SVT). Une étude approfondie des étapes de fabrication et en particulier de la gravure sèche a été réalisée pour obtenir une gravure verticale des matériaux constituants les ICLs. Les premiers ICLs à fentes ont été fabriqués démontrant un e une émission monomode en régime continu à température ambiante avec une émission proche de 3.4 µm. Sur cette base, l'ICL SVT a été fabriqué pour étendre la plage d'accord et démontrer que l'accord par effet Vernier pouvait être mis en œuvre sur ce système de matériaux
Interband cascade lasers (ICLs) provide sources for the mid-infrared spectral range between 3 – 6 µm with low power consumption and efficient performance. This spectral range is of particular interest to the detection of gases involved with petrochemical processing, such as methane, ethane, and carbon dioxide due to their strong absorption in this range. Correct identification of a gas present in a sample requires single-mode emission and some tuning to match the absorption line, depending on the environmental conditions. Increasing the tuning range possible with one laser source opens up new possibilities in spectroscopic applications. An economical design alternative to what is currently commercially available can be realized through the use of slotted waveguides, which can be fabricated using photolithography, reducing the cost of fabrication.Two new types of ICLs have been designed, fabricated, and studied in this thesis: a single-section slotted ICL and a multi-section slotted Vernier tuned (SVT) ICL. An extensive study of the fabrication step and in particular dry etching was carried out to achieve vertical etching of the materials constituting the ICLs. First, the slotted ICLs were fabricated demonstrating single-mode emission in continuous wave operation at room temperature with emission close to 3.4 µm. Building from this foundation, the SVT ICL was fabricated to extend the tuning range and demonstrate that Vernier tuning could be implemented on this material system
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Wlotzko, Vincent. « Conception et réalisation d'une caméra à balayage de fente à résolution temporelle picoseconde et à haut taux de répétition ». Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAD009/document.

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Les caméras à balayage de fente sont les instruments de détection directe de la lumière les plus précis en termes de résolution temporelle. Ces instruments sont capables de capturer des évènements de l’ordre de la picoseconde à un taux de répétition d’une centaine de mégahertz. Cependant, les performances de la caméra sont limitées par de nombreux phénomènes propres au fonctionnement de cette dernière mais aussi au système l’implémentant. Plusieurs effets dégradant la résolution temporelle sont étudiés. Le premier axe exploré concerne la synchronisation de la caméra avec l’évènement lumineux capturé. Cette investigation débouche sur le développement d’un discriminateur à fraction constante permettant de déclencher la caméra avec un jitter inférieur à 200 fs RMS. Une autre étude présente l’impact qu’ont le bruit d’amplitude et le bruit de phase des lasers usuellement utilisés avec la caméra sur sa synchronisation. Enfin une analyse des phénomènes intrinsèques à la photocathode de la caméra permet d’évaluer la variation du temps de transit des électrons dans celle-ci
Streak cameras are the direct light detection instruments that are the best in terms of temporal resolution. Those instruments can capture picosecond light events at a hundred megahertz repetition rate. However their characteristics are limited by various phenomena specific to the camera and the implementing system. Several effects that affect the temporal resolution are studied. The first examined line deals with the synchronization of the camera with the studied light event. This inquiry led to the design of a constant fraction discriminator allowing a sub 200 fs RMS jitter triggering. Another study shows the impact of the usually used laser amplitude noise and phase noise on the system’s synchronization. Finally, an analysis of the camera’s photocathode intrinsic phenomena allows estimating the transit time variation of the electrons within the vacuum tube
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Paquet, Caroline. « Étude de la diffraction d'impulsions laser brèves par une fente ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0018/MQ49042.pdf.

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Perez, José. « Étude par transillumination laser d'organes de mammifères avec analyse spectrale et résolution temporelle ». Paris 12, 1987. http://www.theses.fr/1987PA120010.

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Debray, Sylvain. « Dispositifs pour la transillumination laser des tissus biologiques : apport de la résolution temporelle et de l'analyse spectrale ». Paris 12, 1987. http://www.theses.fr/1987PA120009.

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Bonté, Christophe. « Caractérisation spectrale et temporelle de l'émission X issue de l'interaction laser - agrégats ». Phd thesis, Université Sciences et Technologies - Bordeaux I, 2006. http://tel.archives-ouvertes.fr/tel-00720164.

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Les agrégats de gaz rare constituent un état de la matière intermédiaire entre les cibles solides et les atomes en phase gazeuse. Il a été démontré que les agrégats irradiés sont sources d'ions, d'électrons, de neutrons énergétiques ainsi que de rayonnement allant du visible aux X durs. Cette source peut-être produite avec un taux de répétition élevé et a l'avantage de ne pas produire de débris, et de présenter une très forte conversion de l'énergie laser incidente. Nous nous intéressons au rayonnement X particulièrement, en le caractérisant en intensité, spectre et durée, comme préalable à toute application. En collaboration avec l'INRS-Energie (Varenne, Canada), nous avons mis en œuvre une caméra à balayage de fente dont la résolution temporelle est de 800 fs rms. En focalisant des impulsions laser courtes (30 fs - 5 ps) et intenses (jusqu'à 1e17 W/cm2) sur des agrégats d'argon (15 - 30 nm), nous avons démontré que l'émission X dont l'énergie est supérieure à 2 keV est plus courte que la résolution temporelle. En couplant la caméra à un cristal tronconique, nous nous sommes intéressés au rayonnement de couche K dans la gamme 2,9 - 3,2 keV. Nous avons démontré que ce rayonnement a une durée inférieure à la résolution temporelle, et que les raies étaient émises avec un écart temporel relatif inférieur à 1 ps. Une simulation basée sur un modèle nano-plasma et sur un code collisionnel-radiatif a été développée au CELIA. Les spectres X résolus en temps calculés reproduisent à la fois la brièveté d'émission du rayonnement X et les états de charge élevés observés.
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Chapitres de livres sur le sujet "Lasers à fente"

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Yang, Yingyi, Hao Wu, Fan Yang, Xiaoming Mai et Hui Chen. « Design and Implementation of Substation Operation Safety Monitoring and Management System Based on Three-Dimensional Reconstruction ». Dans Machine Learning and Artificial Intelligence. IOS Press, 2020. http://dx.doi.org/10.3233/faia200793.

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In order to reduce operational risks and to improve the risk management and control level in substation, a substation operation safety monitoring and management system (3D2S2M) has been structured based on three-dimensional (3D) laser modeling technology. In this paper, we introduce how to build such a system and to describe its implementation details. A 3D lidar scanning technology is used to perform a holographic scan of the whole internal area in a substation to obtain color point cloud data of buildings and all equipment. Then, a novel 3D visualization safety monitoring and management system, named 3D2S2M, is developed by performing a 3D reconstruction of the point cloud data. Based on the real 3D scene model of 3D2S2M, the method of 3D distance measurement is used to replace manual on-site investigation for improving operation and maintenance efficiency. In addition, a real-time high-accuracy localization method is proposed, in order to identify and analyze the positioning and the behavior of the personnel, and the movement trajectory of the equipment. By combining positioning information and the electronic fence that used in 3D2S2M, risk levels of the personnel (or equipment) are evaluated and the corresponding alarm is issued to prevent dangerous behavior, thereby the operation risk is reduced in substation.
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Actes de conférences sur le sujet "Lasers à fente"

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Chung, J. T., T. W. Simon et J. Buddhavarapu. « Three-Dimensional Flow Near the Blade/Endwall Junction of a Gas Turbine : Application of a Boundary Layer Fence ». Dans ASME 1991 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1991. http://dx.doi.org/10.1115/91-gt-045.

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A flow management technique designed to reduce some harmful effects of secondary flow in the endwall region of a turbine passage is introduced. A boundary layer fence in the gas turbine passage is shown to improve the likelihood of efficient film cooling on the suction surface near the endwall. The fence prevents the pressure side leg of the horseshoe vortex from crossing to the suction surface and impinging on the wall. The vortex is weakened and decreased in size after being deflected by the fence. Such diversion of the vortex will prevent it from removing the film cooling flow allowing the flow to perform its cooling function. Flow visualization on the suction surface and through the passage shows the behavior of the passage vortex with and without the fence. Laser Doppler velocimetry is employed to quantify these observations.
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Firdhous, M. F. M. « IoT-enhanced Smart Laser Fence for Reducing Human Elephant Conflicts ». Dans 2020 5th International Conference on Information Technology Research (ICITR). IEEE, 2020. http://dx.doi.org/10.1109/icitr51448.2020.9310854.

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Rothenberg, J. E. « Ultrafast 'picket fence' pulse shapes to enhance frequency conversion of ICF laser drivers ». Dans Conference on Lasers and Electro-Optics (CLEO 2000). Technical Digest. Postconference Edition. TOPS Vol.39. IEEE, 2000. http://dx.doi.org/10.1109/cleo.2000.907359.

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Sivakov, A. G., I. S. Dudar, S. I. Bondarenko, A. S. Pokhila, A. V. Krevsun, Y. S. He et L. X. Cao. « Laser scanning microscopy of superconductive parameters of iron-containing chalcogenide FeTe films ». Dans 2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves (MSMW). IEEE, 2013. http://dx.doi.org/10.1109/msmw.2013.6622177.

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Chunjuan, Junjie et Jian. « A design of alarm system for substation perimeter based on laser fence and wireless communication ». Dans 2010 International Conference on Computer Application and System Modeling (ICCASM 2010). IEEE, 2010. http://dx.doi.org/10.1109/iccasm.2010.5620690.

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Chen, Ruirui, Xiaolong Wang, Jian Wang, Chaoyang Duan et Xiaofeng Zhang. « Application of small nano-laser electronic fence combined with ultrasonic bird repellent device to monitor bird damage on power transmission lines ». Dans 2022 4th International Academic Exchange Conference on Science and Technology Innovation (IAECST). IEEE, 2022. http://dx.doi.org/10.1109/iaecst57965.2022.10061967.

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Hu, J. Stephen, Jian Sheng, Michele Guala et Leonardo Chamorro. « High Speed PIV Measurement of Impinging Flow on a Horizontal Axis Wind Turbine ». Dans ASME 2012 Fluids Engineering Division Summer Meeting collocated with the ASME 2012 Heat Transfer Summer Conference and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/fedsm2012-72346.

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The focus of this paper is to characterize the upstream wake of a three bladed Horizontal Axis Wind Turbine (HAWT) and its interaction with the native structures within a turbulent boundary layer (TBL). The overarching question is the most prevailing length and time scales of coherent structures that would interact with a HAWT and how they would be affected. The implications include wall flow and structure interaction and flow induced noise generation in large scale turbo machineries. The experiments are performed on a turbine that has a 0.128 m rotor diameter, a hub height of 0.104 m and a tip speed ratio of 4. The HAWT model is placed in a large scale wind tunnel in a boundary layer with a thickness δ of ∼0.6 m. The boundary layer is generated by a 60 mm picket fence trip and developed over a smooth wall under thermally neutral conditions. Measurements are performed under ReD of 4 × 105 and 6 × 105. Both turbine geometries and flow conditions are scaled from operating conditions in the field. High speed Particle Image Velocimetry (PIV), turbine voltage output, and angular velocity measurements are conducted simultaneously, by which one could relate the upwind flow structures with the power output of the turbine. High speed PIV offer details in spatial and temporal characteristics of the impinging flow structures, whilst the voltage anemometer and tachometer provide instantaneous measurement of angular velocity of the turbine. PIV measurements are taken at a rate of 1500 image pairs per second with a 100 μs delay between laser pulses. Each sample area is 0.15 × 0.15 cm. Two locations up to two rotor diameters upwind are measured. Instantaneous voltage is taken at a sampling rate of 30 kHz and a sampling time of 60s to ensure sufficient temporal resolution and coverage. Ongoing analysis using conditional averaging based on extreme power output events will provide insights in assessing a HAWT performance in unsteady flow conditions.
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Nguyen, T. D., M. Elhajem, Q. Nguyen, S. Simoëns, A. Delache et J. L. Balint. « Non-Newtonian Fluids Mixing Behavior Behind a Grid ». Dans ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-86125.

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Numerous biological, biomedical or chemical engineering processes involve non-Newtonian fluids as shear-thinning or shear-thickening fluids. As early as 1969, Lumley [1] investigated the influence of the non-Newtonian characteristics on the Kolmogorov cascade. In 1986, De Gennes [2] revisited such point of view by considering more precisely elasticity and shear thinning properties. As of today, the correlation between elasticity and other flow properties is still unclear, recent numerical simulations attempted to clarify the issue with the use of FENE-P or other linear viscoelastic models. The goal of this experimental work is to further clarify these assumptions by using new optical tools (PIV, PLIF) to study non-Newtonian decaying isotropic homogeneous turbulence (IHT), using the approach and analysis of the 1971 work of Comte-Bellot and Corrsin [3] for Newtonian fluids, and more recently (2010, 2011) by Lenoir et al. [4]. The experimental set-up consists of a small, 1m long liquid channel, with a cross-section of 6.6 × 6.6 cm2, as in Simoëns and Ayrault [5]. In order to obtain best possible quasi-isotropic flow for sufficient large Reynolds numbers (see Comte-Bellot and Corrsin [6]), the grid was installed transversally upstream the flow, at the outlet of a contraction chamber; the grid squared mesh was 8mm wide. A PIV Lavision System with two synchronized pulsed YAG Lasers was used to obtain Instantaneous velocity maps on selected vertical plane crossing longitudinally the channel at its center. The flow was seeded with 10μm diameter fluorescent particles for PIV measurements. IHT experiments were done on a 1% carboxymethyl cellulose (CMC) aqueous solution (such dilute CMC solution is non-Newtonian as shown in the 2008 work of Benchabane and Bekkour [7]) and then compared to measurements in water at the same flow rate. To prevent molecular modification of the CMC fluid structure out of its natural shear stress, the flow was driven by gravity, not by a pump. For this study, the water flow Reynolds number was 1600; the flow regime was too low to reach a turbulent state. Frequent rheometer checks were performed during the CMC experiments to verify the preservation of the integral shear thinning properties of the fluids. For the CMC flow, the Reynolds number was determined locally, based on the local viscosity after a Carreau-Yasuda model of order 2, in which γ̇ is the rate of shear strain, η is the viscosity at iteration n, η0 is the viscosity at zero shear rate; λ is a constant with units of time, where 1/λ is the critical shear rate at which viscosity begins to decrease (see Nguyen et al. (2010, 2012) [8], [9]).
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