Articles de revues : « Laser scanning technique »

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MacFarlane, D. L., W. Y. Kim, J. S. Nilvi, T. Nuth et V. Tan. « Novel two-dimensional laser scanning technique ». Optics and Lasers in Engineering 17, n^o 1 (janvier 1992) : 1–8. http://dx.doi.org/10.1016/0143-8166(92)90022-y.

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Altyntsev, Maxim A., et Hamid Majid Saber Karkokli. « TECHNIQUE OF AUTOMATIC MOBILE LASER SCANNING DATA FILTERING ». Vestnik SSUGT (Siberian State University of Geosystems and Technologies) 26, n^o 3 (2021) : 5–19. http://dx.doi.org/10.33764/2411-1759-2021-26-3-5-19.

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The result of laser scanning is an array of laser points. The generation of a single point cloud in a given coordinate system is carried out during the registration process at the stage of preliminary field data processing. At this stage it is also often necessary to filter the data. Laser points with an erroneous position are eliminated during the data filleting. The number of erroneous laser points is determined by the of the laser scanner characteristics, surveyed area peculiarities and weather conditions. The devel-opment of methods and algorithms for filtering laser scanning data is carried out based on the analysis of the laser point spatial position and a certain set of additional characteristics, such as intensity value, echo signal, color value. The technique of mobile laser scanning data filtering for the territory of the road passing among the forest and close to individual industrial facilities and building. The main goal of the proposed filtration technique is to obtain data for automatic generation of an accurate digital terrain model. The filtration technique was developed for data acquired under the least favorable con-ditions – in wet weather. Accuracy estimation of generating digital terrain model based on filtered data was carried out.

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Gulino, Michelangelo-Santo, Mara Bruzzi et Dario Vangi. « Line Scanning with Gas-Coupled Laser Acoustic Detection ». Journal of Physics : Conference Series 2293, n^o 1 (1 juin 2022) : 012009. http://dx.doi.org/10.1088/1742-6596/2293/1/012009.

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Abstract The Gas-Coupled Laser Acoustic Detection (GCLAD) is an optical technique for ultrasonic detection based on the deviation that a laser beam sustains when travelling in a fluid that features refractive index fluctuations. If the laser beam is perpendicular to the wave propagation direction, the technique enables simultaneous detection of direct waves in mechanical components and eventual echoes from defects to be achieved. The technique is applied to the inspection of elements predominantly extending in one/two dimensions as bars and axisymmetric pieces, exploiting a signal enhancement effect occurring in defects’ proximity. The phenomenon, namely constructive interference between wave crests of a direct Rayleigh ultrasound and those associated with reflections on a defect flank, is first illustrated numerically. The effect of parameters like the angle between wave propagation direction and source-receiver distance on the GCLAD sensitivity is then experimentally highlighted. The technique is finally implemented to B-scan a steel plate with 1 mm wide, 20 mm long, and 3 mm deep surface defects. Since the GCLAD probe laser beam insists on an entire line, defects present on that line can be identified without moving the device along such direction. This reduces the monitoring time compared to techniques leveraging on traditional air-coupled transducers or more sophisticated methods (Scanning Laser Source).

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Altyntsev, Maxim A., et Karkokli Hamid Majid Saber. « TECHNIQUE OF AUTOMATIC MOBILE LASER SCANNING DATA ADJUSTMENT ». Vestnik SSUGT (Siberian State University of Geosystems and Technologies) 26, n^o 4 (2021) : 5–23. http://dx.doi.org/10.33764/2411-1759-2021-26-4-5-23.

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Adjustment is a main step in the preliminary processing of mobile laser scanning (MLS) data. As a result of this step, a point cloud is generated in a certain coordinate system. The modern software, provided with the corresponding surveying system, is capable of performing in automatic mode most stages of MLS data adjustment obtained for territories with different quantity of buildings. With a suf-ficient number of vertically arranged planar objects, such as building walls, the algorithms embedded in the software provide a high accuracy of relative adjustment, which consists in calculating and ap-plying corrections for trajectories obtained with re-scanning the same area. Absolute adjustment can also be carried out automatically, subject to the rules for placing control points in order to automatically detect them. This kind of adjustment involves transforming a point cloud with using control point coordinates measured with more accurate surveying methods. The accuracy of automatic relative adjustment can be significantly reduced with the almost complete absence of vertical flat objects. In this case, it is necessary to develop additional adjustment techniques capable of using not only flat objects of a large area, but also vertical objects, such as road signs and poles. Comprehensive technique of MLS data adjustment, which can use information on the position of road signs and poles for territories with an insufficient number of vertical flat objects is proposed. The accuracy estimation of both the relative and absolute MLS data adjustment according to the proposed technique was carried out. The choice of the required control point density for territories with different quantity of buildings is explained.

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Nguyen Tien Thanh, Nguyen Tien Thanh, 刘修国 Liu Xiuguo, 王红平 Wang Hongping, 于明旭 Yu Mingxu et 周文浩 Zhou Wenhao. « 3D Model Reconstruction Based on Laser Scanning Technique ». Laser & ; Optoelectronics Progress 48, n^o 8 (2011) : 081201. http://dx.doi.org/10.3788/lop48.081201.

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Fuad, N. A., A. R. Yusoff, M. P. M. Zam, A. Aspuri, M. F. Salleh, Z. Ismail, M. A. Abbas, M. F. M. Ariff, K. M. Idris et Z. Majid. « EVALUATING MOBILE LASER SCANNING FOR LANDSLIDE MONITORING ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W4 (6 mars 2018) : 211–19. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w4-211-2018.

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Abstract. Landslide is one of the natural disasters that give a huge impact to human life and social-economic development. Landslide needs to be monitored periodically in order to avoid loss of human life and damages of properties. Various methods have been used for monitoring landslide. This aim of the research is to evaluate the potential of mobile laser scanning technique for monitoring of landslide area. The objectives of the research are to acquire three-dimensional surface data of landslide area in different epochs and to analyze the movement of the landslide area using three-dimensional surface deviation and ground surveying techniques. The methodology begins with the GPS survey for the establishment of ground control points for the project area. The total station survey was then carried out to measure the three-dimensional coordinates of twenty well distributed targets located at the project area. The data collection phase was then continuing with the mobile laser scanning survey. The processing of the two epochs data acquired from both techniques was then carried out simultaneously and the methodology concluded with the output comparison analysis for the movement detection of the land slip. The finding shows that the mobile laser scanning provides fast and accurate data acquisition technique of the landslide surface. The surface deviation analysis of the two epochs laser scanning data was capable to detect the movement occurred in the project area. The results were successfully evaluated using the changes of the three-dimensional coordinates of the targets from the two epoch’s ground surveying data.

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Uotila, Ulrika, Arto Saari et Juha-Matti Junnonen. « Investigating the barriers to laser scanning implementation in building refurbishment ». Journal of Information Technology in Construction 26 (27 mai 2021) : 249–62. http://dx.doi.org/10.36680/j.itcon.2021.014.

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The use of the laser scanning technique has increased rapidly in the field of built environment, mainly because it produces highly accurate as-built data. However, the full potential of this technique is utilised only limitedly in building refurbishment projects. This research aims to investigate the barriers to the implementation of laser scanning in building refurbishment projects in Finland. Qualitative interviews were carried out to identify these barriers, and furthermore, to explore the current usage of the technique in building refurbishments. The study shows that many obstacles to implementations are related to challenges in laser scanning procurement, including a low level of competence in acquisition, limitations of the laser scanning technique in building refurbishments, and limitations and challenges in utilising the data in design work. This study is beneficial for building owners and practitioners as it presents the challenges and advantages that laser scanning can provide a refurbishment project. In addition, it offers suggestions to improve the early phase of a refurbishment project in order to achieve greater benefits with laser scanning. Furthermore, the findings may be utilised in the procurement process of laser scanning services in such projects, and the results may potentially solve practical challenges encountered in laser scanning work.

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Weber, Klaus, Alexander Waletzky, Diana Fendl, Patricia Ordóñez, Pradeep Takawale, Felix Hein, Wolfram Riedel et al. « New Method for Sperm Evaluation by 3-Dimensional Laser Scanning Microscopy in Different Laboratory Animal Species ». International Journal of Toxicology 33, n^o 5 (12 août 2014) : 353–61. http://dx.doi.org/10.1177/1091581814545243.

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Sperm analysis is one of the end points in reproductive toxicology studies. Different methods for quantitative sperm analysis have been described. For qualitative morphological sperm analysis, either such techniques or smears of sperm and histological sperm staging are in use. Any of these methods provides morphological results on a light microscopy level. Laser scanning microscopy is a technique using a focused laser for scanning an object. The Olympus 3D Laser Scanning Microscope LEXT OLS4000 with optional possibilities of differential interference contrast provides a microscopic method for visualizing microasperities, which are far beyond the resolving power of a typical light or laser microscope. This technique was applied to sperm of mice, rats, rabbits, and cynomolgus monkeys at magnifications up to ×17 090. The obtained images are comparable to those of a scanning electron microscope under relatively low-power magnifications. Measurements on sperm parameters were taken by an integrated image analysis software tool. Abnormalities were easily detectable.

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Cheng, P. C., S. J. Pan, A. Shih, W. S. Liou, M. S. Park, T. Watson, J. Bhawalkar et P. Prasard. « Two-Photon Laser Scanning Confocal Microscopy ». Microscopy and Microanalysis 3, S2 (août 1997) : 847–48. http://dx.doi.org/10.1017/s1431927600011120.

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Two-photon fluorescence microscopy has become an important research tool in both biological and material sciences. The technique uses long wavelength, typically in the near IR, as the excitation light to obtain shorter wavelength fluorescence (e.g. visible light). Because of the low linear absorption coefficient of most biological and polymeric specimens, this technique allows deeper penetration of the excitation beam, achieving optical sectioning to a depth of 250μm or more into the specimen. As a result of the quadratic dependency of the two-photon induced fluorescence to the excitation intensity, the fluorescent emission and photobleaching are limited to the vicinity of focal spot. This capability of addressing a specimen’s 3D space allows exciting possibilities in biological researches, such as 3D photobleaching recovery experiment.Two-photon confocal fluorescence microscopy is ideal for the study of thick biological and material specimen in 3D. For example, Figure 1 shows a three-dimensional isosurface rendered image of a vascular bundle from a maize stem.

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Samiei, Mohammad, Seyyed Mahdi Vahid Pakdel, Sahand Rikhtegaran, Sahar Shakoei, Delaram Ebrahimpour et Pedram Taghavi. « Scanning Electron Microscopy Comparison of the Cleaning Efficacy of a Root Canal System by Nd:YAG Laser and Rotary Instruments ». Microscopy and Microanalysis 20, n^o 4 (2 juin 2014) : 1240–45. http://dx.doi.org/10.1017/s1431927614000981.

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AbstractThis study evaluated the cleaning efficacy of a root canal system by Nd:YAG laser and rotary instruments. Sixty single-rooted human teeth were divided into four experimental groups (n=15). In the first group the teeth were prepared with a step-back technique using conventional K-files. In the second and third groups, tooth preparation was carried out using Nd:YAG laser and rotary NiTi instruments, respectively. Teeth in the fourth group were prepared by combined laser and rotary methods. The smear layer remaining on canal walls was then assessed by scanning electron microscopy in the coronal, middle, and apical portions. The comparison of smear layer removal efficacy between groups was carried out by Kruskal–Wallis and Mann–Whitney U tests. The mean grades of smear layer removal in rotary-laser, rotary, laser and step-back techniques were 1.34±0.18, 2.2±0.28, 1.91±0.25, and 2.42 ±0.19, respectively. On the whole, differences between rotary-laser and rotary groups, step-back, and the three other techniques (rotary, laser, and rotary-laser) were significant at p=0.034. Based on the findings of this study, the cleaning efficacy of rotary, laser, and rotary-laser techniques were better than the step-back technique and the combined laser and rotary technique was the most efficient method.

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Li Xiaoying, 李晓莹, 梁晓伟 Liang Xiaowei, 乔大勇 Qiao Dayong, 刘耀波 Liu Yaobo, 潘春辉 Pan Chunhui et 练彬 Lian Bin. « Miniature Laser Projection Display Technique Based on Lissajous Scanning ». Acta Optica Sinica 34, n^o 6 (2014) : 0612005. http://dx.doi.org/10.3788/aos201434.0612005.

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杨, 敏. « Application of 3D Laser Scanning Technique in Complex Surface ». Geomatics Science and Technology 09, n^o 03 (2021) : 82–89. http://dx.doi.org/10.12677/gst.2021.93010.

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Oseni, A. E., O. K. Ajani, A. J. Adewale, O. O. Ayodeji et T. O. Desalu. « 3d Modelling of Structures using terrestrial laser scanning technique ». International Journal of Advanced Engineering, Management and Science 6, n^o 7 (2020) : 316–31. http://dx.doi.org/10.22161/ijaems.67.4.

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Xue, Bin, Xiaoxia Yang et Jigui Zhu. « Architectural stability analysis of the rotary-laser scanning technique ». Optics and Lasers in Engineering 78 (mars 2016) : 26–34. http://dx.doi.org/10.1016/j.optlaseng.2015.09.005.

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Song, Jung Han, Y. Zhang, J. Lee, Geun An Lee, Sang Mok Lee, H. W. Lee et S. J. Park. « A Numerical Approach to Shape Correction of Stamped Products Using Laser Forming Techniques ». Key Engineering Materials 535-536 (janvier 2013) : 239–42. http://dx.doi.org/10.4028/www.scientific.net/kem.535-536.239.

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Laser forming is an advanced process in sheet metal forming in which a laser heat source is used to shape the metal sheet. In this paper, shape correction of stamped product using the laser forming technique is numerically invesitgaed. As a fundamental study, laser irradiated bending process has been analyzed through the thermo-mechanical FE analysis. Laser scanning experiments has been also conducted for varificaiton of numerical simulations. Finally, the laser forming technique is applied to the u-shaped channel member for springback compensation. It is observed that laser irradiation gives the desired bending angle to compensate the springback by controlling the process parameters such as the laser power, scanning speeds and the number of laser scanning.

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Teng, Xu, Feng Li et Chao Lu. « Visualization of materials using the confocal laser scanning microscopy technique ». Chemical Society Reviews 49, n^o 8 (2020) : 2408–25. http://dx.doi.org/10.1039/c8cs00061a.

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Al-Tamimi, Haneen M., Ahmed O. Al-Roubaiy et Nawal Mohammed Dawood. « Improvement of Microstructure and Wear resistance of X12 Tool Steel by Using Laser Surface Re-Melting Technique ». Materials Science Forum 1021 (février 2021) : 260–69. http://dx.doi.org/10.4028/www.scientific.net/msf.1021.260.

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Nd-YAG lasers have been successfully used in recent years as reliable heat source to surface modification of engineering materials such as laser surface re-melting. In the present study, X12 tool steel was surface modified by using pulse Nd-YAG laser technique. Laser parameters are selected of 12 J pulse energy, 15 Hz frequency, 20 mm defocus length, 6 ms pulse duration, and 5.6 mm /s mm scanning speed. These parameters were chosen after undertaking trials to give suitable parameters in this process. Optical microscopy and backscattered scanning electron microscopy (SEM) with EDS and X-ray diffraction techniques were used to analyse the microstructure changes of the surface of tool steel. Wear resistance test was achieved by using a pin on disk method. The reason for this work is to improve the wear resistance for surface layer of tool steel after changes the morphology of the structure by rapid solidification during laser re-melting. In general, the structure consists of the dendrite and cellular structures with δ ferrite formed under conditions of rapid solidification without the primary coarse carbides. After laser melting, the results of the structure at the surface layers show an increase in wear resistance.

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McDevitt, T. E., G. H. Koopmann et C. B. Burroughs. « Two-Channel Laser Vibrometer Techniques for Vibrational Intensity Measurements : Part 1—Flexural Intensity ». Journal of Vibration and Acoustics 115, n^o 4 (1 octobre 1993) : 436–40. http://dx.doi.org/10.1115/1.2930369.

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A laser technique which measures vibrational energy flow (intensity) via propagating bending waves is described. A pair of scanning laser beams from a two-channel laser vibrometer is used to provide a nonintrusive measurement of the intensity at various points on a vibrating beam. Results are shown to compare well with those of two additional techniques. These techniques, used for validation, employ a single laser beam and can only be used at resonance frequencies in beams or rods. The two-channel laser technique described can be applied to two-dimensional intensity measurements, is not limited to single frequency excitation, and has an inherent capability to facilitate phase error elimination via a photodetector switching technique which is also described.

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Hollaus, M., W. Wagner et K. Kraus. « Airborne laser scanning and usefulness for hydrological models ». Advances in Geosciences 5 (16 décembre 2005) : 57–63. http://dx.doi.org/10.5194/adgeo-5-57-2005.

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Abstract. Digital terrain models form the basis for distributed hydrologic models as well as for two-dimensional hydraulic river flood models. The technique used for generating high accuracy digital terrain models has shifted from stereoscopic aerial-photography to airborne laser scanning during the last years. Since the disastrous floods 2002 in Austria, large airborne laser-scanning flight campaigns have been carried out for several river basins. Additionally to the topographic information, laser scanner data offer also the possibility to estimate object heights (vegetation, buildings). Detailed land cover maps can be derived in conjunction with the complementary information provided by high-resolution colour-infrared orthophotos. As already shown in several studies, the potential of airborne laser scanning to provide data for hydrologic/hydraulic applications is high. These studies were mostly constraint to small test sites. To overcome this spatial limitation, the current paper summarises the experiences to process airborne laser scanner data for large mountainous regions, thereby demonstrating the applicability of this technique in real-world hydrological applications.

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Zaczek-Peplinska, Janina, Paweł Popielski, Adam Kasprzak et Paweł Wójcik. « Development of Large Concrete Object Geometrical Model Based on Terrestrial Laser Scanning ». Reports on Geodesy and Geoinformatics 97, n^o 1 (3 février 2015) : 91–102. http://dx.doi.org/10.2478/rgg-2014-0014.

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AbstractThe paper presents control periodic measurements of movements and survey of concrete dam on Dunajec River in Rożnów, Poland. Topographical survey was conducted using laser scanning technique. The goal of survey was data collection and creation of a geometrical model. Acquired cross- and horizontal sections were utilised to create a numerical model of object behaviour at various load depending of changing level of water in reservoir. Modelling was accomplished using finite elements technique. During the project an assessment was conducted to terrestrial laser scanning techniques for such type of research of large hydrotechnical objects such as gravitational water dams. Developed model can be used to define deformations and displacement prognosis.

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Lee, H. M., Y. H. Kwon, Hyo Seon Park et I. Lee. « Displacement Measurement of an Existing Long Span Steel Box-Girder Using Terrestrial Laser Scanning ». Key Engineering Materials 347 (septembre 2007) : 511–16. http://dx.doi.org/10.4028/www.scientific.net/kem.347.511.

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To make use of a new technology in the field of structural health monitoring, various displacement measuring techniques such as a global positioning system (GPS) and vision-based techniques have been studied and proposed. It was previously introduced a new displacement measuring technique using terrestrial laser scanning (TLS) that remotely samples the surface of an object using laser pulses and generates the three-dimensional (3D) coordinates of numerous points on the surface. In this paper, for an assessment of the capabilities of the measuring technique about existing structures, the field tests for vertical displacement measurement of an existing long span steel box-girder are experimentally carried out. The performance of the technique is evaluated by comparing the displacements obtained from TLS system and displacements directly measured from linear variable displacement transducer (LVDT).

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Sharafutdinova, Anzhelika A., et Michael Ja Bryn. « TECHNIQUE FOR DESIGNING AND CONSTRUCTING A GEODETIC NETWORK WHEN PERFORMING TERRESTRIAL LASER SCANNING AT INDUSTRIAL OBJECT ». Vestnik SSUGT (Siberian State University of Geosystems and Technologies) 27, n^o 2 (2022) : 72–85. http://dx.doi.org/10.33764/2411-1759-2022-27-2-72-85.

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When performing terrestrial laser scanning of large industrial facilities, it must give special atten-tion to designing and establishing a geodetic network to datum transformation measurements into a coordinate system. However, the design of geodetic networks by traditional geodesy methods does not consider all the features of the technique of terrestrial laser scanning. Also worth taking into account is the specifics of laser scanning data processing. Therefore, it is necessary to develop a methodology for designing and establishing a geodetic network in the context of terrestrial laser scanning. For this, the article analyzes the features of terrestrial laser scanning of large industrial facilities and methods for measurement results processing. Based on the analysis and practical experience, developing a flow chart for establishing a geodetic network was on the condition that registration of point cloud perform-ing used iterative closest points algorithm and datum transformation coordinate system performing us-ing HDS targets. Also, based on practical experience, the dependence of the values of the root-mean-square error of registration point cloud and the root-mean-square error of laser scanning station posi-tioning on the distance between the stations. As a result, a methodology for designing and establishing the geodetic network has been substantiated, including two stages. The first stage is the design and ac-curacy assessment of the geodetic control network, the coordinates of which are determined from the datum points by traditional geodesy methods. The second stage is the design and accuracy assessment of the laser scanning station positioning, the coordinates of which are determined from the geodetic control network.

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Kossakovski, Dmitri A., John D. Baldeschwieler et J. L. Beauchamp. « Chemical Imaging With a Scanning Probe Microscope ». Microscopy and Microanalysis 5, S2 (août 1999) : 970–71. http://dx.doi.org/10.1017/s1431927600018171.

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Scanning Probe Microscopy (SPM) is a superb tool for topographical analysis of samples. However, traditional varieties of SPM such as Atomic Force, Scanning Tunneling and Near-field Scanning Optical Microscopy have limited chemical contrast capability. Recently, several advanced techniques have been reported which provide chemical information in addition to topographical data. All these methods derive advantage from combinations of scanning probe methodologies and some other, chemically sensitive technique. Examples of such approaches are: Near-field Scanning Raman Imaging, Near-field Scanning Infrared Microscopy and mass spectrometric analysis with laser ablation through fiber probes.In this contribution we report the development of a new method in this family of chemically sensitive scanning probe techniques: Laser Induced Breakdown Spectroscopy with Shear Force Microscopy, LIBS-SFM. Traditional LIBS experiments involve focusing a pulsed laser beam onto the sample and observing optical emission from the plasma formed in the ablation area. The emissions are mostly in the UV/visible range, and the signal is due to electronic transitions in excited atoms and ions in the plasma plume. The spectra are analyzed to identify chemical elements. The spatial resolution of LIBS is limited by the wavelength and beam quality of the laser used for ablation. The experiments may be conducted in vacuum, controlled atmosphere, or ambient air.

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Cardenal Escarcena, Javier, Emilio Mata de Castro, José Luis Pérez García, Antonio Mozas Calvache, Tomás Fernández del Castillo, Jorge Delgado García, Manuel Ureña Cámara et Juan Carlos Castillo. « Integration of photogrammetric and terrestrial laser scanning techniques for heritage documentation ». Virtual Archaeology Review 2, n^o 3 (15 avril 2011) : 53. http://dx.doi.org/10.4995/var.2011.4605.

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This paper presents the preliminary works of the Integration of Photogrammetric and Terrestrial Laser Scanner Techniques for Heritage Documentation Research Project (IFOTEL TIN2009-09939; Ministry of Science and Innovation, National Programme R+D+I, 2008-2011). The IFOTEL project aims with the improvement and optimization of heritage documentation by means of combination and integration of different methods and techniques, mainly close range photogrammetry (both terrestrial and aerial with light platforms), terrestrial laser scanner and surveying, joining the advantages of the different methods but also minimizing the disadvantages of each single technique.

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Fischer, D., G. F. de la Fuente et M. Jansen. « A new pulsed laser deposition technique : Scanning multi-component pulsed laser deposition method ». Review of Scientific Instruments 83, n^o 4 (avril 2012) : 043901. http://dx.doi.org/10.1063/1.3697861.

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Salim, Muhammad Nor, Takahiro Hayashi, Morimasa Murase, Toshihiro Ito et Shoji Kamiya. « Fast Remaining Thickness Measurement Using a Laser Source Scanning Technique ». MATERIALS TRANSACTIONS 53, n^o 4 (2012) : 610–16. http://dx.doi.org/10.2320/matertrans.i-m2012801.

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Choi, Sang Woo, Joon Hyun Lee, An Jin Nam et Sridhar Krishnaswamy. « Application of Scanning Laser Source Technique for Nondestructive Flaw Detection ». Key Engineering Materials 270-273 (août 2004) : 787–92. http://dx.doi.org/10.4028/www.scientific.net/kem.270-273.787.

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Goel, Salil, et Bharat Lohani. « A Motion Correction Technique for Laser Scanning of Moving Objects ». IEEE Geoscience and Remote Sensing Letters 11, n^o 1 (janvier 2014) : 225–28. http://dx.doi.org/10.1109/lgrs.2013.2253444.

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Guan, Jianfei, Zhonghua Shen, Jian Lu, Xiaowu Ni, Jijun Wang et Baiqiang Xu. « Finite Element Analysis of the Scanning Laser Line Source Technique ». Japanese Journal of Applied Physics 45, n^o 6A (8 juin 2006) : 5046–50. http://dx.doi.org/10.1143/jjap.45.5046.

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Sohn, Younghoon, et Sridhar Krishnaswamy. « Mass spring lattice modeling of the scanning laser source technique ». Ultrasonics 39, n^o 8 (juin 2002) : 543–51. http://dx.doi.org/10.1016/s0041-624x(02)00250-0.

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Merson, E., V. Danilov, D. Merson et A. Vinogradov. « Confocal laser scanning microscopy : The technique for quantitative fractographic analysis ». Engineering Fracture Mechanics 183 (octobre 2017) : 147–58. http://dx.doi.org/10.1016/j.engfracmech.2017.04.026.

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Feng, Tian-jin, Xin Li, Guang-rong Ji, Bing Zheng, Hai-yan Zhang, Guo-yu Wang et Guo-xing Zheng. « A new laser-scanning sensing technique for underwater engineering inspection ». Artificial Intelligence in Engineering 10, n^o 4 (novembre 1996) : 363–68. http://dx.doi.org/10.1016/0954-1810(96)00008-8.

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Lehtomäki, Matti, Antero Kukko, Leena Matikainen, Juha Hyyppä, Harri Kaartinen et Anttoni Jaakkola. « Power line mapping technique using all-terrain mobile laser scanning ». Automation in Construction 105 (septembre 2019) : 102802. http://dx.doi.org/10.1016/j.autcon.2019.03.023.

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Jia Li, Jia Li, Liming Dong Liming Dong, Chenyin Ni Chenyin Ni, Zhonghua Shen Zhonghua Shen et Hongchao Zhang Hongchao Zhang. « Application of ultrasonic surface waves in the detection of microcracks using the scanning heating laser source technique ». Chinese Optics Letters 10, n^o 11 (2012) : 111403–6. http://dx.doi.org/10.3788/col201210.111403.

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Skoog, B., P. Helmholz et D. Belton. « MULTISPECTRAL ANALYSIS OF INDIGENOUS ROCK ART USING TERRESTRIAL LASER SCANNING ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B5 (15 juin 2016) : 405–12. http://dx.doi.org/10.5194/isprs-archives-xli-b5-405-2016.

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Multispectral analysis is a widely used technique in the photogrammetric and remote sensing industry. The use of Terrestrial Laser Scanning (TLS) in combination with imagery is becoming increasingly common, with its applications spreading to a wider range of fields. Both systems benefit from being a non-contact technique that can be used to accurately capture data regarding the target surface. Although multispectral analysis is actively performed within the spatial sciences field, its extent of application within an archaeological context has been limited. This study effectively aims to apply the multispectral techniques commonly used, to a remote Indigenous site that contains an extensive gallery of aging rock art. The ultimate goal for this research is the development of a systematic procedure that could be applied to numerous similar sites for the purpose of heritage preservation and research. The study consisted of extensive data capture of the rock art gallery using two different TLS systems and a digital SLR camera. The data was combined into a common 2D reference frame that allowed for standard image processing to be applied. An unsupervised k-means classifier was applied to the multiband images to detect the different types of rock art present. The result was unsatisfactory as the subsequent classification accuracy was relatively low. The procedure and technique does however show potential and further testing with different classification algorithms could possibly improve the result significantly.

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Skoog, B., P. Helmholz et D. Belton. « MULTISPECTRAL ANALYSIS OF INDIGENOUS ROCK ART USING TERRESTRIAL LASER SCANNING ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B5 (15 juin 2016) : 405–12. http://dx.doi.org/10.5194/isprsarchives-xli-b5-405-2016.

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Multispectral analysis is a widely used technique in the photogrammetric and remote sensing industry. The use of Terrestrial Laser Scanning (TLS) in combination with imagery is becoming increasingly common, with its applications spreading to a wider range of fields. Both systems benefit from being a non-contact technique that can be used to accurately capture data regarding the target surface. Although multispectral analysis is actively performed within the spatial sciences field, its extent of application within an archaeological context has been limited. This study effectively aims to apply the multispectral techniques commonly used, to a remote Indigenous site that contains an extensive gallery of aging rock art. The ultimate goal for this research is the development of a systematic procedure that could be applied to numerous similar sites for the purpose of heritage preservation and research. The study consisted of extensive data capture of the rock art gallery using two different TLS systems and a digital SLR camera. The data was combined into a common 2D reference frame that allowed for standard image processing to be applied. An unsupervised k-means classifier was applied to the multiband images to detect the different types of rock art present. The result was unsatisfactory as the subsequent classification accuracy was relatively low. The procedure and technique does however show potential and further testing with different classification algorithms could possibly improve the result significantly.

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Bleier, M., et A. Nüchter. « LOW-COST 3D LASER SCANNING IN AIR ORWATER USING SELF-CALIBRATING STRUCTURED LIGHT ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W3 (23 février 2017) : 105–12. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w3-105-2017.

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In-situ calibration of structured light scanners in underwater environments is time-consuming and complicated. This paper presents a self-calibrating line laser scanning system, which enables the creation of dense 3D models with a single fixed camera and a freely moving hand-held cross line laser projector. The proposed approach exploits geometric constraints, such as coplanarities, to recover the depth information and is applicable without any prior knowledge of the position and orientation of the laser projector. By employing an off-the-shelf underwater camera and a waterproof housing with high power line lasers an affordable 3D scanning solution can be built. In experiments the performance of the proposed technique is studied and compared with 3D reconstruction using explicit calibration. We demonstrate that the scanning system can be applied to above-the-water as well as underwater scenes.

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Kubanova, A. A., A. A. Kubanov, V. A. Smolyannikova, N. V. Gribanov et YU B. Makhakova. « Diagnostic value of the confocal laser scanning microscopy in vivo ». Vestnik dermatologii i venerologii 91, n^o 3 (24 juin 2015) : 67–74. http://dx.doi.org/10.25208/0042-4609-2015-91-3-67-74.

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The confocal laser scanning microscopy in vivo is a promising study method to visualize cell structures of epidermis and papillary dermis without affecting the skin integrity, which provides for a resolution and contrast similar to those characteristic of the classical histology examination. Goal. To assess the confocal laser scanning microscopy in vivo (CLSM) technique for diagnosing actinic keratosis, psoriasis vulgaris and rosacea vs. the classical histology examination. Study materials. The article describes the results obtained by using the confocal laser scanning microscopy in vivo technique vs. the histology examination in 10 patients with erythematous actinic keratosis, 10 patients with extensive psoriasis and 10 patients with erythematous and papulous rosacea. Results. The article describes diagnostically significant signs of the diseases detected by using the confocal laser scanning microscopy in vivo as well as the potential of this method in terms of diagnosing inflammatory skin diseases.

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Jo, Y. H., et J. Y. Kim. « THREE-DIMENSIONAL DIGITAL DOCUMENTATION OF HERITAGE SITES USING TERRESTRIAL LASER SCANNING AND UNMANNED AERIAL VEHICLE PHOTOGRAMMETRY ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W5 (18 août 2017) : 395–98. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w5-395-2017.

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Three-dimensional digital documentation is an important technique for the maintenance and monitoring of cultural heritage sites. This study focuses on the three-dimensional digital documentation of the Magoksa Temple, Republic of Korea, using a combination of terrestrial laser scanning and unmanned aerial vehicle (UAV) photogrammetry. Terrestrial laser scanning mostly acquired the vertical geometry of the buildings. In addition, the digital orthoimage produced by UAV photogrammetry had higher horizontal data acquisition rate than that produced by terrestrial laser scanning. Thus, the scanning and UAV photogrammetry were merged by matching 20 corresponding points and an absolute coordinate system was established using seven ground control points. The final, complete threedimensional shape had perfect horizontal and vertical geometries. This study demonstrates the potential of integrating terrestrial laser scanning and UAV photogrammetry for three-dimensional digital documentation. This new technique is expected to contribute to the three-dimensional digital documentation and spatial analysis of cultural heritage sites.

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Chen, Chin Sheng, Wei Ke Wang, Chien Liang Huang et Chun Wei Yeh. « Field Distortion Compensation for Galvanometric Scanning Machines ». Applied Mechanics and Materials 284-287 (janvier 2013) : 2746–50. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.2746.

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The laser manufacture has been widely used in micro-machining as a burgeoning technology. Galvanometric scanning systems is an important component in laser machines, but the galvanometric scanning system is usually combines the image field distortion that is from the mechanism and optical devices. The paper has presented a novel correction algorithm based on ride regression method for compensates the image field distortion. And the Euclidean distance error and the maximum error are 0.0422 and 0.09, respectively. This novel correction technique can effectively increase the accuracy of laser spot position and can further improve the performance of the galvanometric scanning system.

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Liu, Qiang, Fuqiang Shi, Xuguang Wang et Mingsheng Zhao. « Statistical Estimation of Blast Fragmentation by Applying 3D Laser Scanning to Muck Pile ». Shock and Vibration 2022 (26 septembre 2022) : 1–15. http://dx.doi.org/10.1155/2022/3757561.

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Run-of-mine fragmentation is an important aspect of mine productivity optimization, as it affects all mine-to-mill processes. The current blasting fragmentation calculation methods do not consider the 3D geometric information. Therefore, their calculation results are imprecise. 3D laser scanning is a technique for extracting the 3D geometric information of an object by constructing a 3D point cloud model, with which extra information on the geometrical characteristics of an object could be captured than with the technique of 2D image processing. In this paper, 3D laser scanning technology was utilized for the calculation of the rock blocks on the surface of a muck pile, and the information about the surface blocks was utilized as the samples for the statistical estimation of blasting fragmentation of muck pile (BFMP). Monte Carlo simulation was utilized as the statistical estimation method for the BFMP. In the lab experiment, results from 2D image processing technique and from 3D laser scanning technique combined with statistical estimate were compared with the physical measurements utilizing a water tank, which show that results with 3D laser scanning are more similar to the physical measurement. Finally, the applicability of 3D laser scanning technology combined with statistical methods to the calculation of blast fragmentation was estimated through field tests in Biesikuduke and Santanghu mine, two open-pit coal mines in Xinjiang Province of western China. Results show that the accuracy of the statistical estimation results of BFMP has a particle size deviation of 1–3 cm.

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Suarez, Ismael F., Felix S. Tembleque, Jose M. R. Sar, Ricardo J. Rivera et Jordi D. Martin. « Feasibility of Laser Scanning to Determine Volumetric Properties of Fine Grained Soils ». Soils and Rocks 38, n^o 1 (1 janvier 2015) : 59–66. http://dx.doi.org/10.28927/sr.381059.

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This study analyses the real applicability of laser scanning techniques to determine bulk densities of fine grained soils. The method, fast and accurate, can be employed both in the field and laboratory. The technique was calibrated with benchmarks and then applied to measure volumes of small samples of a specific silty soil of well-known properties (granite sawdust); next transformed into bulk densities from the sample-weights. The results are compared against those obtained from their precursor specimens, made using the Standard Proctor test. Before calculating soil sample volumes, optimum conditions for data acquisition, exportation and post-processing were assessed. The laser scanning provides highly consistent results when compared with those obtained from Standard Proctor compaction tests. However, the study shows a limiting value of moisture content below which the laser scan provides inaccurate results. Likely, this limit varies from soil to soil and therefore the technique must be calibrated before being used to determine bulk densities and derived volumetric properties (i.e., porosity or void ratio). Accordingly, this work presents a helpful procedure to evaluate the applicability of the laser scanning based on the detection of the limiting water content, which considers as well anomalies derived from compositional heterogeneities or external electromagnetic interferences.

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Semmler, Armin, Reinhold Ferstl et Hans-Helmut Kohler. « New Laser Technique for Automatic Interfacial Tension Measurements : Laser Scanning Drop Shape Analysis (LASDA) ». Langmuir 12, n^o 17 (janvier 1996) : 4165–72. http://dx.doi.org/10.1021/la9515433.

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Nguyen, Tien Thanh, Xiu Guo Liu, You Huang, Hong Ping Wang, Quoc Lap Kieu et Thai Son Dang. « Ore Volume Measurement Based on 3D Laser Scanning Technique : a Case Study ». Advanced Materials Research 610-613 (décembre 2012) : 3708–14. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.3708.

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In the mining industry, conventional methods such as GPS and total station technology are used most extensively for data collection and in return used to compute volume of extracted materials (ore and waste). In situation where the ore body is bigger in size, and changes dynamically, the use of conventional method to measure volume of ore is not practicable and economically viable because of the workload involved, precision and accuracy of the survey and safety of workers. In this paper a method and work flow of ore heap volume measurement by using 3D laser scanning technique to acquire point cloud data was introduced. RiSCAN PRO and Geomagic studio was used to process the original data (registration, noise elimination, georeferencing, resampling etc.), 3D modeling and volume computations. A comparison on precision of geodetic control points coordinate measured by GPS receivers and 3D laser scanner was carried out. The results indicate that 3D laser scanning technique can effectively be applied to ore output volume measurement since it satisfies the requirement of ore volume measurement.

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Jašek, Petr, et Martin Štroner. « Denoising of Laser Scanning Data Using Wavelet ». Geoinformatics FCE CTU 12 (3 juin 2014) : 41–47. http://dx.doi.org/10.14311/gi.12.7.

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Regarding the terrestrial laser scanning accuracy, one of the main problems is the noise in measured distance which is necessary for the spatial coordinates´ determination. In this paper the technique of using the wavelet transformation for the reduction of the noise in the laser scanning data is described. This method of filtration is made in “post processing” and due to this fact any changes in the measuring procedure in the field shouldn´t be done. The creation of the regular matrix is needed to apply image processing. This matrix then makes the range image. In the paper real and simulated efficiency tests of wavelet transformation, the final summary and advantages or disadvantages of this method are introduced.

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Ju, Y. S., et K. E. Goodson. « Short-Time-Scale Thermal Mapping of Microdevices Using a Scanning Thermoreflectance Technique ». Journal of Heat Transfer 120, n^o 2 (1 mai 1998) : 306–13. http://dx.doi.org/10.1115/1.2824246.

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The performance and reliability of microdevices can be strongly influenced by the peak temperature rise and spatial temperature distribution during brief electrical overstress (EOS) phenomena, which can occur at sub-microsecond time scales. The present study investigates short-time-scale laser reflectance thermometry of micro devices by examining the impact of passivation overlayers on the thermoreflectance signal and by demonstrating a calibration method suitable for metallization. This manuscript also describes a scanning laser thermometry facility that captures temperature fields in microdevices with 10 ns temporal resolution and 1 μm spatial resolution. The facility combines scanning laser optics with electrical stressing capability to allow simultaneous interrogation of the thermal and electrical behavior of devices. Data show the transient temperature distribution along the drift region of silicon-on-insulator (SOI) power transistors and along metal interconnects subjected to brief electrical stresses. The theory and experimental capability developed in this study are useful for studying short-time-scale thermal phenomena in microdevices and verifying models employed for their simulation.

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Lee, Changgil, et Seunghee Park. « Flaw Imaging Technique for Plate-Like Structures Using Scanning Laser Source Actuation ». Shock and Vibration 2014 (2014) : 1–14. http://dx.doi.org/10.1155/2014/725030.

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Recently, the longitudinal, shear, and surface waves have been very widely used as ultrasonic wave-based exploration methods to identify internal defects of host structures. In this context, a noncontact nondestructive testing (NDT) method is proposed to detect the damage of plate-like structures and to identify the location of the damage. To achieve this goal, a scanning laser source actuation technique is utilized to generate a guided wave and scans a specific area to find damage location more precisely. The ND:YAG pulsed laser is used to generate Lamb wave and a piezoelectric sensor is installed to measure the structural responses. The measured responses are analyzed using 3-dimensional Fourier transformation (3D FT). The damage-sensitive features are extracted by wavenumber filtering based on the 3D FT. Then, flaw imaging techniques of a plate-like structure are conducted using the damage-sensitive features. Finally, the plates with notches are investigated to verify the effectiveness and the robustness of the proposed NDT approach.

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Goeckeritz, Jeremy, Gary Aden et Ami Chand. « Nanometer Thermal Conductivity Mapping Using Laser-based Scanning Thermal Microscopy ». MRS Proceedings 1754 (2015) : 81–86. http://dx.doi.org/10.1557/opl.2015.256.

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ABSTRACTA new measurement technique using a cantilever probe with an integrated thermal sensor is investigated for measuring thermal conductivity at the nanometer scale. The probe is used in a configuration wherein the laser from an atomic force microscope (AFM) heats the tip of the probe above ambient temperature. Heat is transferred from the probe to a sample based on the thermal conductivity of the sample. The heat flow creates a temperature change, as small as 0.01 °C, which is detected by the thermal sensor. The measurement technique presented offers a simple and effective method for mapping the thermal conductivity of a number of materials. We explore the ability of the technique to map silicon oxide on silicon, carbon fibers and gold nanoparticles. Analysis shows that the technique can be used to produce images with a thermal resolution surpassing 25 nm.

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Opoka, Szymon, Pawel Malinowski, Tomasz Wandowski, L. Skarbek et Wieslaw Ostachowicz. « Damage Detection Using Electromechanical Impedance Technique Combined with Scanning Laser Vibrometry ». Key Engineering Materials 569-570 (juillet 2013) : 687–94. http://dx.doi.org/10.4028/www.scientific.net/kem.569-570.687.

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The paper consists of two parts. First, Electromechanical Impedance (EMI) method is proven to be able to determine some vibrational characteristics of the investigated structure. In order to verify this statement, Scannig Laser Vibrometry (SLV) is used to correlate frequency peaks of velocity (or displacement) operational deflection shapes with corresponding ones obtained by EMI method. Finally, the influence of moisture content in CFRP sample on resonance peaks is investigated using EMI method. Damage detection indicator in this case is based on shifts of resonant peaks.

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Blotter, Jonathan D., Robert L. West et Scott D. Sommerfeldt. « Spatially Continuous Power Flow Using a Scanning Laser Doppler Vibrometer ». Journal of Vibration and Acoustics 124, n^o 4 (20 septembre 2002) : 476–82. http://dx.doi.org/10.1115/1.1497363.

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This paper presents the validation of an experimental technique that maps the transfer of energy in vibrating structures. The technique is known as Experimental Spatial Power Flow (ESPF) and is unique in that it provides a spatially continuous representation of the power flow based on measurements from a scanning laser Doppler vibrometer. In this paper, the ESPF technique is validated by showing that ESPF results compare to within 10 percent of the results obtained using single point impedance head measurements. A simply supported plate excited by two shakers phased to act as an energy source and sink is used as the test object.

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