Thematische Bibliographien / Scanning electron microscopy (MEB)

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Auswahl der wissenschaftlichen Literatur zum Thema „Scanning electron microscopy (MEB)“

Autor: Grafiati

Veröffentlicht am 31. Oktober 2023

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Zeitschriftenartikel zum Thema "Scanning electron microscopy (MEB)"

Rong, Yun Long, Shao Fei Wang, Dan Dan Jia, Chun Liu, Lei Cao, Hong Yan Tian, Xue Fang Zheng, Lu Liu und Dong Jun Wang. „Preparation of Porous Carbon Material by Carbonizing Polyacrylonitrile Microspheres“. Applied Mechanics and Materials 253-255 (Dezember 2012): 884–87. http://dx.doi.org/10.4028/www.scientific.net/amm.253-255.884.

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PAN microspheres were crosslinked with divinyl benzene (DVB) and styrene (St), and then pre-oxidized under atmospheric pressure, porous carbon microspheres were produced by carbonizing the pretreated microspheres under nitrogen protection. Morphology and structure characterizations of the materials were performed by employing scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption test, etc. The results show that the primitive PAN microspheres display flower-like structures, while the carbonized pretreated PAN microspheres exhibit a high porosity as well as specific surface area and have a good adsorption of methylene blue (MeB) dye.

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Naggar, Ahmed H., Ahmed Kotb, Ahmed A. Gahlan, Mahmoud H. Mahross, Abd El-Aziz Y. El-Sayed und Adel A. Abdelwahab. „Graphite Studded with Facile-Synthesized Cu2O Nanoparticle-Based Cubes as a Novel Electrochemical Sensor for Highly Sensitive Voltametric Determination of Mebeverine Hydrochloride“. Chemosensors 9, Nr. 2 (09.02.2021): 35. http://dx.doi.org/10.3390/chemosensors9020035.

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Herein, a feasible chemical reduction method followed by intensive mixing was applied for the preparation of an attractive material based on graphite studded with cuprous oxide nanoparticle-based cubes (Cu2ONPs–C@G). Transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD) and cyclic voltammetry (CV) were utilized for characterization. Cuprous oxide nanoparticles (Cu2ONPs), with a diameter range mainly distributed from 4 to 20 nm, aggregate to form microcubes (Cu2ONPs–C) with an average diameter of about 367 nm. Paste electrode was prepared using Cu2ONPs–C@G (Cu2ONPs–C@G/PE) for voltametric quantification of the musculotropic antispasmodic drug: mebeverine hydrochloride (MEB). The electrochemical behavior of MEB was studied using CV, and the optimum analytical parameters were investigated using square wave adsorptive anodic stripping voltammetry (SWAdASV). Moreover, density functional theory (DFT) was used to emphasize the ability of MEB to form a complex with Cu2+, confirming the suggested electrochemical behavior of MEB at Cu2ONPs–C@G/PE. With good stability and high reproducibility, SWAdASV of Cu2ONPs–C@G/PE shows successful quantification of MEB over the concentration range of 5.00 × 10−11–1.10 × 10−9 M with lower limit of detection (LOD) and lower limit of quantification (LOQ) values of 2.41 × 10−11 M and 8.05 × 10−11 M, respectively. Finally, accurate quantification of MEB in dosage forms (tablets) and biological fluids (spiked human urine and plasma samples) was achieved using Cu2ONPs-C@G/PE.

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Vanfleet, R. R., D. Muller, H. J. Gossmann und J. Silcox. „Antimony Delta Doping by Scanning Transmission Electron Microscopy and Electron Energy Loss Spectroscopy“. Microscopy and Microanalysis 5, S2 (August 1999): 614–15. http://dx.doi.org/10.1017/s1431927600016391.

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MBE techniques allow the fabrication of exceptionally sharp compositional changes such as delta doped layers in semiconductors. Producing these spatially confined doped layers is critical to many innovative device designs. The spatial confinement of these delta doped structures can be less than the measurement resolution of the currently standard SIMS and RBS techniques. This allows only the upper limits on the layer width to be measured. These SIMS and RBS methods are also inadequate for the two dimensional information desired for future device design and development. More recently developed techniques such as Scanning Capacitance Microscopy and spreading resistance measurement give two dimensional information but have similar spatial resolution issues. The Z-contrast nature of Annular Dark Field (ADF) imaging with the complimentary technique of Electron Energy Loss Spectroscopy (EELS) in the Scanning Transmission Electron Microscope (STEM) shows promise for two dimensional dopant profiling with spatial resolution on the atomic scale.

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Guerrero, Gabriela Peñuelas, Ingrid Jiménez Cosme, Pilar Tapia López, José Luis Ruvalcaba Sil, Jesús Arenas, Aurore Lemoine, Jannen Contreras Vargas, Patricia Ruiz Portilla und Sonia Rivero Torres. „Technical Study of a set of Metallic Artifacts from the Maya Site of Lagartero, Chiapas, Mexico“. MRS Proceedings 1374 (2012): 125–35. http://dx.doi.org/10.1557/opl.2012.1383.

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ABSTRACTDuring the excavations made at a burial of the post-Classic Mayan period (1220-1521 A.D.) in the pyramid number 2 of the pre-Hispanic site of Lagartero, Chiapas, Mexico, a set of four small metallic artifacts depicting reptile’s heads, were recovered. The objects were in poor conservation conditions and were taken to the Metal Conservation Laboratory of the National School of Conservation (ENCRyM- INAH) for suitable cleaning and conservation treatments.Analyses allowed identifying important technological features such as gilding remains. The analytical techniques included optical microscopy followed by X-Ray Fluorescence Spectroscopy (XRF), and Scanning Electron Microscope-coupled with Energy Dispersive Spectrometer (MEB-EDS). For the elemental depth profile a combined Particle X-Ray Emission Spectroscopy and Rutherford Backscattering Spectrometry (PIXE–RBS) analysis was carried out.The results indicate that the objects are made of a copper alloy, and then gilded probably using electrochemical replacement gilding (thickness has less than 1 μm). This technology has been observed in other metallic objects recovered from the Chichen-Itza Cenote in Yucatan, but it was not available in Mesoamerican areas so far. So, it could imply that these artifacts might have been imported from South American areas.

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TANAHASHI, Katsuto, Yuichi KAWAMURA, Naohisa INOUE und Yoshikazu HOMMA. „Three Dimensional Growth in GaAs MBE Studied by in-situ Scanning Electron Microscopy.“ Hyomen Kagaku 19, Nr. 11 (1998): 747–51. http://dx.doi.org/10.1380/jsssj.19.747.

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Tanahashi, K., Y. Kawamura, N. Inoue, Y. Homma und J. Osaka. „Surface-roughening processes in GaAs MBE studied by in situ scanning electron microscopy“. Journal of Crystal Growth 188, Nr. 1-4 (Juni 1998): 205–10. http://dx.doi.org/10.1016/s0022-0248(98)00066-9.

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Lloret, Fernando, D. Araujo, M. P. Villar, L. Liu und Konstantinos Zekentes. „Si NWs Conversion to Si-SiC Core-Shell NWs by MBE“. Materials Science Forum 821-823 (Juni 2015): 965–69. http://dx.doi.org/10.4028/www.scientific.net/msf.821-823.965.

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Si nanowires (NWs) samples have been converted to silicon carbide (SiC) NWs at different conditions of substrate temperature in an ultra-high vacuum using a molecular beam epitaxy (MBE) set-up. Auger electron spectroscopy (AES) and reflection high-energy electron diffraction (RHEED) have been in-situ carried out to control the growth process. Scanning electron microscopy (SEM) and conventional transmission electron microscopy (CTEM) have been used to characterize the resulting nanostructures. In addition, the samples have been prepared by focused ion beam (FIB) in order to have electron-transparently lamellas for TEM with the interface nanowire-substrate. SiC/Si shell/core NWs free of planar defects have been obtained for conversion tmpratures lower than 800oC.

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Aguilera Mandujano, A., und J. Serrato Rodriguez. „Synthesis and characterization of titania/graphene nanocomposite for application in photocatalysis“. Revista Mexicana de Física 66, Nr. 5 Sept-Oct (01.09.2020): 610. http://dx.doi.org/10.31349/revmexfis.66.610.

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Titanium dioxide has been extensively investigated as a photocatalyst for water purification, presenting limitations such as recombination of electron-hole pairs generated by photons. The titania / graphene nanocomposites are promising materials to overcome these limitations due to the high specific area of graphene and unique electronic properties. In this work, an anatase-graphene nanocomposite was synthesized by a simple mixture assisted by ultrasound. Graphene was obtained by electrochemical exfoliation of graphite using the electrolysis technique. On the other hand, anatase was synthesized using the sol gel method. The obtained graphene, anatase and the nanocomposite material, were characterized with the X-ray diffraction technique (DRX), scanning electron microscopy (MEB) and transmission electron microscopy (MET). Using Raman spectroscopy, it was possible to verify that the graphite exfoliated correctly producing few layer-graphene. The lamellar nano-structure of the exfoliated graphite has crystallographic planes characteristic of graphite, graphene and graphene oxide. The presence of the anatase phase is shown in the diffraction spectrum of titania. The images obtained with SEM and TEM of the graphene sample show a layered lamellar structure and the TiO2 images show agglomerates of ellipsoidal nanoparticles. Obtained titania nanoparticles have a size of about 6 nm. Band gap value for such extremely low particle size nanocomposite is around 3.6 eV and presumably corresponds to the TiO2 (anatase) phase that completely surrounds the graphene. A nanocomposite model based on HRTEM observations is proposed. Considering the graphene electrical properties and the photocatalytic properties of TiO2, this nanocomposite promises to have applications in photocatalysis.

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Zsebök, Otto, Jan V. Thordson, Qingxiang Zhao, Ulf Södervall, Lars Ilver und Thorvald G. Andersson. „The Effect of Al in Plasma-assisted MBE-grown GaN“. MRS Internet Journal of Nitride Semiconductor Research 5, S1 (2000): 209–15. http://dx.doi.org/10.1557/s1092578300004294.

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We have grown GaN, with addition of a 0.10 to 0.33 % Al, on sapphire(0001) substrates by solid-source RF-plasma assisted MBE. The Al-concentration was determined by secondary ion-mass spectrometry and Auger-electron spectroscopy, while the layer quality was assessed by photoluminescence and high-resolution scanning electron microscopy. Microscopy revealed a meandering pattern and a surface roughness varying with Al-content. The smallest surface roughness was obtained at 0.10 % Al. Photoluminescence revealed two main peaks attributed to the neutral donor-bound exciton. Its energy increased slightly with Al-concentration, which established a correlation between the Al-concentration and the band gap.

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Fan, Yunan, und Fugang Qi. „Effect of rapid cold stamping on the precipitation and mechanical properties of Al–Cu–Mg alloy“. Materials Express 12, Nr. 2 (01.02.2022): 355–61. http://dx.doi.org/10.1166/mex.2022.2142.

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High-angle annular dark-field scanning transmission electron microscopy, scanning electron microscopy, and tensile tests were used to investigate the effects of rapid cold stamping deformation on the precipitation and mechanical properties of spray-formed fine-grained Al–Cu–Mg alloy during aging. The number of longplate S′ phases in peak-aged samples evidently increases with increasing number of rapid cold stamping passes. After two passes of rapid cold stamping, the distribution of long-plate S′ phases in the samples is evidently uneven, with high density in some areas and low density in some areas. The S′ phases are refined, the number is further increased, and the distribution is uniform after four passes of rapid cold stamping deformation. The overall performance of the material is excellent. The tensile strength, yield strength, and elongation are 512 MPa, 453 MPa, and 11.2%, respectively.

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Dissertationen zum Thema "Scanning electron microscopy (MEB)"

Gaudenzi, de faria Marcelo. „Robust control for manipulation inside a scanning electron microscope“. Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2068/document.

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Cette thèse étudie le problème de nano-positionnement à l'intérieur d'un microscope électronique à balayage (MEB). Pour obtenir des informations de position avec rapidité et précision, une installation dédiée composée d’un vibromètre placé à l'intérieur du MEB a été mise en œuvre. Cette approche diffère de méthodes basées sur le traitement d'images, car elle permet de saisir des données en temps réel sur le comportement dynamique des structures étudiées. Dans une première étude, les perturbations mécaniques agissant à l'intérieur de la chambre à vide du microscope ont été caractérisées et leurs sources ont été identifiées. Cela a démontré comment les vibrations mécaniques externes et les bruits acoustiques peuvent influer largement sur les composants à l'intérieur du MEB par couplage mécanique, limitant ainsi la précision des manipulateurs. Dans un deuxième temps, une micro-pince du commerce a été étudiée. Une différence entre ses comportements dans l'air et dans le vide a été mise en évidence, ce qui a permis d'obtenir deux modèles dynamiques pour cet organe terminal, un pour chaque environnement. Deux lois de commande ont été proposées (commande H-infini et commande basée sur un observateur d'état étendu), afin d'obtenir en temps réel un positionnement précis dans le vide, et d'atténuer les effets des perturbations mécaniques externes. Les résultats ont été validés en simulation et expérimentalement
This work studies the nano-positioning problem inside the scanning electron microscope (SEM). To acquire fast and accurate positional information, a dedicated setup was implemented consisting of a vibrometer placed inside the SEM. This approach differs from methods based on image processing, as it allows to capture real-time data on the dynamic behavior of structures. In a first study, the mechanical disturbances acting inside the microscope’s vacuum chamber were characterized and its sources were identified. This demonstrated how external mechanical vibrations and acoustic noises can largely influence the components inside the SEM through mechanical coupling, limiting the effective positioning precision of manipulators. Next, a commercial micro-gripper was studied, both in air and in vacuum, and the differences between its response were highlighted. This allowed to obtain two dynamic models for this end-effector, one for each environment. Two control laws were proposed (H-infinity control and Extended State Observer based control) for the system, to obtain a real-time, precise positioning in the vacuum environment and to attenuate the effects of the external mechanical disturbances. Results were demonstrated through simulation and experimental validation

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Comby, Dassonneville Solène. „Développement et application d'un nanoindenteur in situ MEB couplé à des mesures électriques“. Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI047/document.

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L’essor de la demande actuelle pour des matériaux architecturés, en microélectronique par exemple, ou pour des matériaux de structure, nécessite le développement d’outils de caractérisation toujours plus performants. Dans cette optique, un instrument de caractérisation multifonctionnel basé sur un couplage mécanique / électrique, a été développé au laboratoire SIMaP. Le cœur de ce dispositif est un nanoindenteur in situ FEG-SEM (Field Emission Gun Scanning Electron Microscope) couplé à des mesures électriques. Ce travail est porté par trois principales motivations: (1) L’étude du comportement mécanique d’objets petites échelles, (2) L’apport des données électriques à l’analyse quantitative du comportement mécanique pendant l’indentation, en particulier pour obtenir une meilleur estimation de l’aire de contact, (3) L’étude locale des propriétés électroniques d’empilements de films minces. L’intégration in situ SEM a été validée et permet un positionnement des indents avec une précision meilleure que 100 nm, autorisant ainsi l’étude des propriétés mécaniques à l’échelle submicrométrique. La rapidité des essais permet également des mesures statistiques. Des caractérisations mécaniques ont été menées aussi bien sur des échantillons composites massifs que sur des ilots d’or submicrométriques. Pour ce dernier cas, malgré la nature stochastique de leur comportement mécanique, une loi déterministe a pu être extraite des données mécaniques. Des mesures 3D-BCDI (Bragg Coherent Diffraction Imaging) au synchrotron ont été réalisées sur certains ilots avant et après chargement mécanique, révélant une germination de dislocations avant l’avalanche de grandes déformations plastiques. En parallèle de cette étude, des mesures électriques ont été réalisées pendant l’indentation de divers échantillons. Des mesures de nanoindentation résistive ont ainsi été effectuées sur des métaux nobles (Au) ou recouverts de leur oxyde natif (Cu, Al), soit à l’état de monocristal massif ou de film polycristallin. Les résultats quantitatifs soulignent l’importance de la présence d’une couche d’oxyde sur la réponse électrique. En présence d’un oxyde, l’interface pointe / échantillon semble être le lieu d’importantes réactions électrochimiques. En l’absence d’oxyde, la résistance mesurée peut être entièrement décrite par un modèle analytique. Dans ce cas, l’aire de contact électrique peut être prédite à partir des mesures de résistance. Enfin, des mesures capacitives ont été réalisées sur des structures MOS avec différentes épaisseurs d’oxyde. Les résultats expérimentaux sont parfaitement décrits par un modèle analytique, ce qui ouvre la voie à des mesures locales de permittivité diélectrique sous contrainte mécanique
The increasing demand for multifunctional materials has become a recurrent challenge for a wide panel of application fields such as microelectronics and structural applications. Within the frame of this project, a multifunctional characterisation set-up has been developed at SIMaP lab, mainly based on the electrical / mechanical coupling. The heart of this device is an in situ FEG-SEM (Field Emission Gun Scanning Electron Microscope) nanoindenter coupled with an electrical measurement apparatus. This work has threefold objectives: (1) The investigation of mechanical behavior of small scale systems, (2) The input of electrical data to the quantitative analysis of mechanical behavior during indentation, in particular to obtain a better estimation of the contact area (3) The local study of electronic properties of thin film stacks. SEM integration of the device has been validated and indent positioning with a precision better than 100 nm is successfully obtained. This performance allows the studies of mechanical properties at submicrometric length scale, with a high throughput allowing statistical measurements. Various bulk composite materials have been characterized as well as submicrometric gold islands on sapphire. In the latter case, despite the stochastic nature of their mechanical behavior, a deterministic law has been extracted. 3D-BCDI (Bragg Coherent Diffraction Imaging) experiments have been performed on a few islands at synchrotron facility to investigate the crystal state before and after mechanical loading. These experiments reveal initial dislocation nucleation prior to large deformation bursts. In parallel to this study, electrical measurements have been performed during indentation on various cases. Resistive-nanoindentations have been performed on noble metals (Au) and natively oxidized metals (Cu, Al), either as bulk single crystals or as polycrystalline thin films. Qualitative results emphasize the importance of the oxide layer on the electrical response. In the presence of an oxide layer, strong electrochemical reactions seem to occur at the tip-to-sample interface. When no oxide is involved, the measured resistance can be fully described by an analytical model and the computed electrical contact area is successfully validated with residual areas measurements. Finally, capacitive measurements have been performed on MOS structures with various oxide thicknesses. Experimental results have been well described by analytical modelling, which paves the way for quantitative local dielectric permittivity measurements under mechanical loading

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Liu, Yang. „‘Tri-3D’ electron microscopy tomography by FIB, SEM and TEM : Application to polymer nanocomposites“. Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0076/document.

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Ce travail a porté sur la caractérisation et la quantification en 3D de la répartition de charges de différents types (nanoparticules, nanotubes, etc.) dans des matrices polymères. Nous nous focalisons sur les techniques de tomographie en microscopie électronique. Une approche multiple en tomographie électronique a été réalisée : la tomographie en FIB/MEB (faisceau d’ions focalisé/microscope électronique à balayage), la tomographie en MEB et la tomographie en MET (microscope électronique en transmission). Les nanocomposites polymère sont généralement élaborés aux fins d’améliorer les propriétés physiques (mécanique, électrique, etc.) du matériau polymère constituant la matrice, grâce à une addition contrôlée de charges nanométriques. La caractérisation de tels matériaux, et l’établissement de corrélations précises entre la microstructure et les propriétés d’usage, requièrent une approche tri-dimensionnelle. En raison de la taille nanométrique des charges, la microscopie électronique est incontournable. Deux systèmes de nanocomposite polymère ont été étudiés par une approche multiple de tomographie électronique : P(BuA-stat-S)/MWNTs (copolymère statistique poly (styrène-co-acrylate de butyl) renforcé par des nanotubes de carbone multi-parois), et P(BuA-stat-MMA)/SiO2 (copolymère statistique poly(butyl acrylate-co-methyl methacrylate) renforcé par des nanoparticules de silice). Par combinaison de divers techniques, la caractérisation et la quantification des nanocharges ont été possibles. En particulier, la taille, la fraction volumique et la distribution des charges ont été mesurées. Cette étude a ainsi fourni des informations en 3D qui contribuent à mieux comprendre les propriétés des nanocomposites. Une attention particulière a été portée aux artefacts et causes d’erreur possibles durant l’étape de traitement 3D. Nous avons également essayé de comparer les différentes techniques utilisées du point de vue de leurs avantages et inconvénients respectifs, en dégageant des possibilités d’amélioration future
This work is focused on the characterization and quantification of the 3D distribution of different types of fillers (nanoparticles, nanotubes, etc.) in polymer matrices. We have essentially used tomography techniques in electron microscopy. Multiple approaches to electron tomography were performed: FIB-SEM (focused ion beam/scanning electron microscope) tomography, SEM tomography and TEM (transmission electron microscope) tomography. Polymer nanocomposites are basically synthesized in order to improve the physical properties (mechanical, electric, etc.) of the pure polymer constituting the matrix, by a controlled addition of fillers at the nanoscale. The characterization of such materials and the establishment of accurate correlations between the microstructure and the modified properties require a three-dimensional approach. According to the nanometric size of the fillers, electron microscopy techniques are needed. Two systems of polymer nanocomposites have been studied by multiple electron tomography approaches: P(BuA-stat-S)/MWNTs (statistical copolymer poly(styrene-co-butyl acrylate) reinforced by multi-walled carbon nanotubes) and P(BuA-stat-MMA)/SiO2 (statistical copolymer poly(butyl acrylate-co-methyl methacrylate) reinforced by silica nanoparticles). By combining various techniques, the characterization and the quantification of nanofillers were possible. In particular, statistics about size, distribution and volume fraction of the fillers were measured. This study has then provided 3D information, which contributes to a better understanding of properties of the nanocomposites. Attention has been paid to analyze carefully original data, and artifacts and causes of errors or inaccuracy were considered in the 3D treatments. We also attempted to compare benefits and drawbacks of all techniques employed in this study, and perspectives for future improvements have been proposed

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Crouzier, Loïc. „Développement d'une nouvelle approche hybride combinant AFM et MEB pour la métrologie dimensionnelle des nanoparticules“. Thesis, Poitiers, 2020. http://www.theses.fr/2020POIT2260.

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Afin de bénéficier des propriétés uniques des nanomatériaux liés à leur taille mais aussi d'évaluer leurs risques potentiels associés, les acteurs du secteur industriel ont besoin de s’appuyer sur des méthodes de mesure fiables, robustes et permettant d’obtenir l’ensemble des informations dimensionnelles requises. Cependant, il n’existe pas d’instrument capable de mesurer une nanoparticule dans les trois dimensions de l’espace avec une incertitude contrôlée. L’objectif de ces travaux est de combiner les mesures de diamètre par microscopie électronique à balayage (MEB) avec celles de hauteur par microscopie à force atomique (AFM). L’utilisation de particules de silice, supposée sphériques permet de valider cette approche hybride combinant AFM et MEB.Le bilan d’incertitudes associé à la mesure de nanoparticules par MEB a d’abord été établi. Nous avons mis en évidence que la principale contribution au bilan d’incertitudes est la taille du faisceau électronique, difficilement mesurable. Deux méthodes, fondées sur la modélisation Monte Carlo, ont été mises en place pour évaluer l’influence de ce paramètre sur la mesure MEB. La première est fondée sur la comparaison entre les signaux expérimentaux et simulés. La seconde repose sur la segmentation des images MEB en utilisant un point remarquable, non influencé par les dimensions du faisceau électronique. Ces deux méthodes ont permis de montrer que l’erreur liée à la taille du faisceau était largement surestimée en utilisant les outils de segmentation d’images classiques. À partir de ces résultats, une comparaison directe des mesures AFM et MEB a été réalisée sur les mêmes particules. Un écart systématique est observé entre les deux techniques pour les plus petites particules lié à leur non-sphéricité. L’utilisation d’une troisième technique, la microscopie électronique en transmission (MET) permet de confirmer ces observations. Enfin, l’approche de métrologie hybride a été mise en œuvre pour la mesure des trois dimensions caractéristiques de nanoparticules de formes complexes dont la morphologie était éloignée de celle de la sphère
In order to take advantages of remarkable properties of the nanomaterials related to their size but also assess their potential risks, industrial actors need to rely on robust measurement methods that provide all the required dimensional information. However, there is no instrument capable of measuring a nanoparticle in all three dimensions of space with controlled uncertainty. The aim of this work is to combine diameter measurements by scanning electron microscopy (SEM) with height measurements by atomic force microscopy (AFM). The use of silica particles, supposedly spherical, allows to validate this hybrid approach combining AFM and SEM. First, the uncertainty budget associated with the measurement of nanoparticles by SEM was established. We have demonstrated that the main contribution to the uncertainty budget is the size of the electron beam, which is difficult to measure. Two methods, based on Monte Carlo modelling, have been developed to evaluate the influence of this parameter on the SEM measurement. The first is based on the comparison between experimental and simulated signals. The second is based on the segmentation of the SEM images using a remarkable point, not influenced by the dimensions of the electron beam. These two methods have shown that the error related to the beam size is largely overestimated using conventional image segmentation tools. From these results, a direct comparison of AFM and SEM measurements was performed on the same particles. A systematic discrepancy was observed between the two techniques for the smallest particles related to their non-sphericity. The use of a third technique, transmission electron microscopy (TEM), confirms these observations. Finally, the hybrid approach has been implemented for measuring the three characteristic dimensions of the complex-shaped nano-objects with very non-spherical morphology

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Foulon, Anthony. „Détermination de la signature acoustique de la corrosion des composites SVR (stratifiés verre résine)“. Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2204/document.

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Depuis les années 80, Les matériaux composites stratifié verre résine (SVR) ont été utilisés pour la construction des tuyaux et des réservoirs dans l'industrie chimique, y compris pour le stockage d’acides. Ce matériau composite présente une résistance supérieure à la corrosion. Cependant, des auteurs ont observé des ruptures accidentelles de réservoirs (horizontaux et verticaux) contenant des acides (chlorhydrique et sulfurique). Ces ruptures sont attribuées au mécanisme de corrosion sous contrainte (CSC). La corrosion des fibres de verre dans une solution acide est moins connue mais reste très importante. Ce mécanisme de corrosion, appelée désalcalinisation de la fibre peut provoquer la fissuration de la fibre de verre.Des essais de corrosion avec de l’acide chlorhydrique (37%) ont été effectués sur éprouvette SVR. Ces essais de corrosion ont été suivis par émission acoustique. Les observations au microscope électroniques à balayage (MEB) et les analyses physico-chimiques confirment la corrosion de fibres de verre dans une solution de HCl. L’utilisation de la micro-tomographie nous montre que cette technique permet d’avoir une information sur la profondeur d’attaque du matériau.Une approche statistique est utilisée pour caractériser les paramètres de la salve d’émission acoustique afin de les séparer. Le Clustering est fait en utilisant la méthode des k-moyennes. Trois classes d’émission acoustique distinctes ont ainsi été identifiées. L’analyse croisée de l’émission acoustique et des observations ont permis de relier les classes observées aux conséquences de la corrosion du SVR
Since the 1980, Glass Reinforced Plastic (GRP) has been used for construction of pipes and tanks in the chemical industry, including the storage of mineral acids. This composite material offers superior and cost effective corrosion resistance. However, authors found accidental breakage of tanks (horizontal and vertical) containing mineral acids (hydrochloric and sulphuric). These failures are attributed to environmental stress-corrosion cracking (ESCC) mechanism. The corrosion of glass fibers in mineral acid solution is less known but very important. The mechanism of the corrosion, called leaching, is thought to induce tensile stresses in the surface of the glass. These stresses could be large enough to cause cracking of the fiber glass.Corrosion tests have been performed on GRP specimen. Aggressive environments used are hydrochloric acid (37%) This environment is known to react with E-glass. Corrosion tests have been monitored by acoustic emission.SEM observations and physicochemical analysis confirm the corrosion of glass fibers in HCl solution. The use of micro - tomography allows to have information on the depth of degradation of the material.Statistical approaches are used to characterize hit’s parameters. Clustering is made by using k-mean’s method. Three distinct acoustic emission classes are identified. Thanks to SEM observations and acoustic emission results, clusters can be assigned to the appearance of minor defects in the material

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Frallonardo, Paola. „Ruolo dei cristalli di calcio nell'infiammazione. Studio del liquido sinoviale mediante Microscopia Elettronica a Scansione, in pazienti con artrosi del ginocchio“. Doctoral thesis, Università degli studi di Padova, 2014. http://hdl.handle.net/11577/3423989.

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Background Osteoarthritis (OA) is a chronic joint disease characterized by a progressive loss of articular cartilage, osteophyte formation, thickening of the subchondral bone, along with frequent signs of intraarticular inflammation with moderate synovitis. The role of inflammation in the pathogenesis of OA is becoming increasingly evident especially in its early phases The pathogenesis is not yet clear. In the last years the role of calcium crystals in structural progression of OA was considered. Calcium pyrophosphate (CPP) and basic calcium phosphate (BCP) are the most common calcium crystals detected in OA. The role of calcium crystals in synovial inflammation and their significance in OA progression in this context continues to be debatable. Objective The aim of this study was to evaluate the presence of calcium crystals in synovial fluid using ultrasensitive analysis with scanning electron microscopy (SEM) at early and later stages of symptomatic and radiographic knee OA (KOA), to investigate the presence of CPP and BCP crystals in synovial fluid (SF) of patients with KOA and their relationship with main indices of clinical and synovial activities. Methods SF was collected from 120 patients affected with KOA, 84 females, mean age 68±10.7 yrs (range 50-93 yrs). All patients answered at three disease-specific questionnaires: WOMAC, Lequesne algofunctional index and VAS. SF calcium crystals analysis was performed by regular and polarized light microscopy. Alizarin red stain was performed in all speciments. As BCP crystals are more challenging to detect and are too small to be seen by light microscopy, SEM a highly specialized technique, has been used to define calcium-containing crystals. All patients underwent to knee ultrasound (US) with power Doppler. Everyone were undergoing knee X-ray and they were classified according to the radiological grade of Kellgren and Lawrence (KL). Results CC were detected by SEM in 62/120 (51.6%) of the patients. The patients with CC were older (p=0.036), had a greater difficulty in moving (p=0.0041); they had a higher PMN percentage in SF (0.0041) and a positive power Doppler statistically significant (p=<0.0001). CPP were positive in 37/120 patients (30%) by SEM. In patients with CPP, we found a significant difference with regard to age (p=0.0002), disease duration (p=0.041), pain (p=0.039), KL radiographic score (p=0.0334), US power Doppler (p=0.0001). BCP were detected by SEM in 33/120 pazienti (27.5%). In patients with BCP+ we found a significant difference with regard to WOMAC (p=0.0001), pain (p=0.0001), stiffness (p<0.0001), functional impairment (p<0.0001), Lequesne index (p<0.0001), Visual Analogic Scale (<0.0004), US power Doppler (p<0.0001). In the group of patients BCP+ we found a correlation between KL score and disease duration. On the basis of disease duration, the patients were subdivided into three groups I <1yr (49); II 1-5 yrs (27); III > 5 yrs (44). The main differences were found with regard to age, US power Doppler. The KL score were worse in III group. In the I group (early KOA) with CPP+ and BCP+ was found significant difference with regard to US Power Doppler (p=0.0039). In the III group we not found significant differences between CPP+ and CPP-. In the I group (early KOA) in patients with BCP+ we found a significant difference with regard to pain (p=0.0002), stiffness (p=0.045), functional impairment (p=0.0014), WOMAC (p=0.0002) US power Doppler (p=0.0009). Conclusion In us study we evaluated the presence of CC in LS of patients with KOA, using ultrasensitive method as the SEM. CC+ was found to be correlated with severe clinical status and worse imaging findings, and PD resulted positive in patients with CC+ by SEM. CC+ appeared to be an expression of worse evolution and aggressive KOA. Particularly intriguing BCP+in the early group. The presence of BCP is associated with a greater degree of inflammation.
Introduzione L'artrosi (OA) è una malattia articolare cronica, caratterizzata da lesioni degenerative e produttive a carico della cartilagine delle articolazioni diartrodiali. Tuttavia, grande interesse della comunità scientifica si è sviluppato attorno alla componente infiammatoria caratterizzata da una modesta sinovite. In questo ambito negli ultimi anni notevole interesse è stato rivolto al ruolo che possono svolgere i cristalli di calcio (CC) nella patogenesi dell'OA, ma se questi contribuiscano direttamente al danno cartilagineo o ne siano più semplicemente un epifenomeno è ancora argomento di dibattito. I CC più comuni nell'OA sono quelli di pirofosfato di calcio diidrato, dall'inglese calcium pyrophosphate (CPP) e quelli generalmente definiti di fosfato basico di calcio (BCP dall'inglese basic calcium phosphate) che comprendono idrossiapatite, octacalcio fosfato e tricalcio fosfato. Scopo dello studio Indagare con metodica ultrasensibile Microscopia Elettronica a Scansione (SEM) la presenza di cristalli di CPP e di BCP nel liquido sinoviale (LS) di pazienti con artrosi del ginocchio (GOA) e sui loro rapporti con i principali indici di attività e di gravità di malattia. Pazienti e metodi Sono stati sottoposti ad artrocentesi del ginocchio ed esame del LS 120 pazienti, 84 femmine, età media 68±10,7 anni (range 50-93). In ciascun paziente sono stati valutati i principali indici clinici di malattia attraverso i questionari WOMAC, Lequesne e VAS; su tutti è stato eseguito esame ultrasonografico (US) dell'articolazione colpita con tecnica power Doppler. Tutti i pazienti soddisfacevano i criteri dell'American College of Rheumatology per OA e avevano una diagnosi radiologica di GOA secondo i criteri di Kellgren e Lawrence (KL). Nel LS sono stati valutati la conta totale leucocitaria (GB), la percentuale di polimorfonucleati (PMN), e la presenza di eventuali CC. La ricerca di CC è stata condotta con microscopio a luce polarizzata, utilizzando anche il compensatore rosso di I ordine; veniva eseguita la colorazione aspecifica con rosso di Alizarina. La microscopia a scansione elettronica (SEM) è stata utilizzata come tecnica ultrasensibile per meglio identificare e caratterizzare i CC. Risultati Il nostro studio ci ha consentito con metodica ultrasensibile (SEM) di rilevare i CC nel LS in 62/120 pazienti (51,6%). Da una prima valutazione delle differenze tra le due popolazioni, i pazienti con CC rispetto a quelli senza erano più anziani (p=0,036), avevano una maggior difficoltà di movimento (p=0,0041); presentavano una % di PMN nel LS superiore (0,0041) e una presenza di power Doppler statisticamente significativa (p=<0,0001). I CPP sono stati evidenziati al SEM in 37/120 pazienti (30%). Nei pazienti con CPP+ abbiamo riscontrato una differenza significativa per età (p=0,0002), durata di malattia (p=0,041), dolore (p=0,039), grado KL (p=0,0334), power Doppler (p=0,0001). Nei pazienti con CPP+ abbiamo riscontrato una correlazione tra loro degli indici clinici: dolore, rigidità , difficoltà , WOMAC, Lequesne. Una correlazione inversa è stata rilevata tra il power Doppler e la conta totale di GB. I BCP sono stati evidenziati al SEM in 33/120 pazienti (27,5%). Nei pazienti con BCP+ abbiamo riscontrato una differenza significativa per WOMAC (p=0,0001), dolore (p=0,0001), rigidità (p<0,0001), difficoltà (p<0,0001), Lequesne (p<0,0001), VAS (<0,0004), power Doppler (p<0,0001); per l'età è stato riscontrato un trend positivo senza significatività statistica (p=0,046). Per quanto riguarda, inoltre, i pazienti con BCP+ abbiamo rilevato una correlazione tra KL e durata di malattia. Abbiamo inoltre suddiviso i pazienti in 3 gruppi in base alla durata di malattia: I gruppo (49) con durata di malattia < 1 anno; II gruppo (27) tra 1-5 anni; III gruppo (44) con durata di malattia > 5 anni. Le differenze principali fra i pazienti dei 3 gruppi sono state riscontrate per l'età , maggiore nel gruppo III, nella positività al power Doppler. La gravità del quadro radiografico erano peggiori nel III gruppo. Quando abbiamo suddiviso i tre gruppi per la presenza di CPP e BCP, nel I gruppo differenze significative si osservavano per il Power Doppler (p=0,0039); al limite della significatività il dolore. Nel III gruppo non abbiamo riscontrato differenze significative tra la presenza e assenza di CPP. Considerando i BCP nel I gruppo sono state riscontrate differenze significative nei BCP+ nei confronti dei BCP- per il dolore (p=0,0002), la rigidità (p=0,045), la difficoltà (p=0,0014), il WOMAC (p=0,0002) e per il power Doppler (p=0,0009). Conclusioni Questo è il primo studio che permette di valutare il significato della presenza di CC nel LS di pazienti affetti da GOA, utilizzando metodica ultrasensibile come il SEM in una popolazione piuttosto ampia di pazienti. Particolarmente intrigante risulta l'analisi di pazienti con BCP nel gruppo early. La presenza dei BCP è sicuramente associata a un grado maggiore di infiammazione e smentirebbe studi precedenti in cui veniva suggerito che i BCP fossero un epifenomeno e non influenzassero il tipo di malattia.

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Ait, Laasri Hicham. „Étude et élaboration de matériaux ferroélectriques sans plomb pour le stockage de l'énergie électrique“. Thesis, Littoral, 2018. http://www.theses.fr/2018DUNK0528/document.

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Les matériaux ferroélectriques présentant une permittivité diélectrique élevée et de faibles pertes diélectriques présentent un grand intérêt pour la réalisation de condensateurs et le stockage de l'énergie électrique. Les propriétés structurales et diélectriques influencent les paramètres ferroélectriques tels que la polarisation maximale du matériau Pm et la polarisation rémanente Pr sous l'effet d'un champ électrique appliqué Em. Ce mémoire propose d'étudier les propriétés structurales, diélectriques et ferroélectriques des céramiques dérivées de BaTiO₃ (BT) et SrTiO₃ (ST) ainsi que des films épais PVDF pur et composites tels que PVDF/BT et PVDF/BZT. Les céramiques ont été synthétisées par la méthode de la réaction solide et le procédé sol-gel. La substitution dans les sites-A ou les sites-B du matériau BaTiO₃ avec des cations tels que Ca ²⁺, Sr²⁺ and Zr⁴⁺ réduit la densité d'énergie électrique stockée Wd et augmente l'efficacité de stockage énergétique η. La céramique BaZr₀.₅Ti₀.₅O₃ (BZT0.5) présente l'efficacité de stockage énergétique la plus élevée (η=75%). La substitution dans les sites-A du matériau SrTiO₃ avec 40% de cations Ca²⁺ diminue la permittivité diélectrique (ε'∽200), mais cette permittivité est cependant plus stable sur une large gamme de fréquence [100 Hz-1 GHz]. La céramique Sr₀.₆Ca₀.₄TiO₃ préparée par voie sol-gel présente la densité d'énergie électrique stockée la plus élevée (Wd=0.149 J/cm³) sous l'action d'un champ électrique maximal élevé (Em=105 kV/cm). Les films épais à base de polymère PVDF ont été synthétisés par Spin-Coating. La permittivité diélectrique des films épais PVDF pur augmente avec l'apaisseur du film. L'incorporation de particules BT et BZT0.15 dans la matrice polymère PVDF augmente la permittivité diélectrique des films composites PVDF/BT (ε'=32 pour 30% de particules BT) et PVDF/BZT0.15 (ε'=32 pour15% de particules BZT)
Ferroelectric materials with a high dielectric permittivity and low dielectric losses are very attractive for the realization of capacitors and for electrical energy storage. To improve the electrical energy density Wd, the structural and dielectric properties influence the ferroelectric parameters such as the maximum polarization Pm and the remanent polarization Pr under an applied electric field Em. This manuscript proposes to study the structural, dielectric and ferroelectric properties of ceramics derived from BaTiO₃ (BT) and SrTiO₃ (ST) as well as pure PVDF thick films and composites such as PVDF/BT and PVDF/BZT. The ceramics were synthesized by the solid state reaction reaction route and the sol-gel process. The subsitution in the A-sites or B-sites of the BaTiO₃ material with cations such Ca²⁺, Sr²⁺ and Zr⁴⁺ reduces the electrical energy density Wd and increases the energy storage efficiency η. The ceramic BaZr₀.₅Ti₀.₅O₃ (BZT0.5) has the highest energy storage efficiency (η=75%). The substitution in the A-sites of SrTiO₃ material with 40% of Ca²⁺ cations reduces the dielectric permittivity (ε'∽200), but is more stable over a wide frequency range [100 Hz -1 GHZ]. The Sr₀.₆Ca₀.₄TiO₃ ceramic prepared by sol-gel process has the highest electrical energy density (Wd = 0.149 J/cm³) under an electrical field Em = 105 kV/cm. The PVDF thick films were synthesized by Spin-Coating. The dielectric permittivity of pure PVDF thick films increases when increasing the thickness. The addition of BT and BTZ0.15 particles in the PVDF polymer matrix increases the dielectric permittivity of the composite PVDF/BT thick films (ε'=32 for 30% of BT particles) and PVDF/BZT0.15 ones (ε'=32 for 15% of BZT particles)

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Davies, D. G. „Scanning electron acoustic microscopy“. Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304042.

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Zhao, Dan. „Study on the creep behavior of clay under complex triaxial loading in relation to the microstructure“. Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0372/document.

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Cette recherche vise à analyser et à identifier, par des essais, le comportement au fluage d'une argile de type kaolinite sous un état de contraintes triaxial. Une investigation fine de l’état microstructural, avant et après fluage, a par ailleurs été réalisée. Les résultats macroscopiques ont permis de constater que des phénomènes de dilatance et de contractante s’amplifient pendant le fluage. Les résultats montrent également que la position, sur le plan des contraintes (p'-q), du niveau de contrainte vis-à-vis des différents domaines volumétriques, contrôle le développement de la déformation au fluage et du taux de déformation. Les résultats de MEB ont montré que l'évolution microstructurale de l'argile, après le chargement mécanique, dépend fortement de l'histoire du chargement
The objective of this research is to analyze the creep behavior of a typical clay along triaxial tests, moreover, to analyze the microstructural mechanisms of creep. Analysis on the macroscopic results ascertained that both dilatancy and contractancy phenomena could occur during creep. The magnitude of the dilatancy/contractancy during creep was guided by the test conditions: stress level and the over consolidation ratio, which specifically governed the direction of the volumetric strain variations. The results of SEM indicated that the microstructural evolution of the clay after the mechanical loading depend on the stress history. Afterwards, the structural evolution in creep phase depends on the structural pattern developed in monotonic loading

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Rima, Wael. „Apport de la microscopie electronique dans la compréhension des mécanismes d’interactions entre nanoparticules et cellules biologiques“. Thesis, Lyon, INSA, 2012. http://www.theses.fr/2012ISAL0131/document.

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Parmi les nanoparticules aptes à accompagner la radiothérapie en clinique, les nanoparticules à base d’oxyde de gadolinium paraissent pertinentes, de part leur multimodalité en imagerie et leur effet radiosensibilisant prouvé in vitro et in vivo. Cet effet de radiosensibilisation est exceptionnel notamment sur des cellules cancéreuses radiorésistantes de la lignée SQ20B (carcinome squameux tête et cou) et uniquement pour des doses modérées de nanoparticules (aux alentours de 0.6 mM en Gd). Les clichés de microscopie électronique ont montré que ce maximum de radiosensibilisation est dû à une internalisation maximale des particules dans le cytoplasme, notamment par macropinocytose. Ce mécanisme d’internalisation est caractérisé par la formation de vésicules de grandes tailles, ou macropinosomes. Il se produit suivant deux étapes : la formation d’agglomérats de nanoparticules à proximité de la membrane cellulaire puis la récupération de ceux-ci par les lamellipodes de la cellule. La première étape est fortement dépendante des caractéristiques physicochimiques des particules, plus particulièrement leur potentiel zêta qui détermine la taille de l’agglomérat, et de la distance les séparant de la cellule. Dans des gammes de taille et de distance à la membrane optimales aux concentrations modérées, l’agglomérat peut être récupéré par les lamellipodes de la cellule. Il s’en suit une protubérance sur la membrane plasmique formant un macropinosome contenant les agglomérats de nanoparticules. Cet endosome précoce suivra ensuite le schéma d’endocytose classique dans le cytoplasme en fusionnant avec des corps multivésiculaires, uniquement visible en microscopie électronique à transmission, pouvant contenir des enzymes de dégradation détruisant leur contenu. Ces enzymes rendent le pH acide à l’intérieur de la vésicule. Plus les nanoparticules sont proches du noyau cellulaire plus leur effet radiosensibilisant sera efficace. Les espèces oxygénées réactives (ROS) et les électrons Auger et secondaires peuvent atteindre l’ADN du noyau plus facilement. A faibles doses (<0.4 mM) très peu de nanoparticules sont internalisées et un effet linéaire de la radiosensibilisation est observé jusqu'à 0.6 mM. A fortes doses (> 0.7 mM) les nanoparticules forment une couronne autour de la membrane cellulaire agissant comme écran, empêchant ainsi les ROS et les électrons générés de pouvoir atteindre l’ADN et induire des cassures, le noyau étant situé à quelques micromètres de la membrane cellulaire. Les résultats obtenus ouvrent la voie sur la nécessité de contrôler l'internalisation cellulaire des nanoparticules en contrôlant leur chimie, laissant envisager ainsi des opportunités prometteuses dans le domaine de la radiothérapie assistée par nanoparticules délivrant de faibles doses de radiation aux patients
Over the last few decades, nanoparticles have been studied in theranostic field with the objective of exhibiting a long circulation time through the body coupled to major accumulation in tumor tissues, rapid elimination, therapeutic potential and contrast properties. In this context, we developed sub-5 nm gadolinium-based nanoparticles that possess in vitro efficient radiosensitizing effects at moderate concentration when incubated with head and neck squamous cell carcinoma cells (SQ20B). Two main cellular internalization mechanisms were evidenced and quantified: passive diffusion and macro- pinocytosis. Whereas the amount of particles internalized by passive diffusion is not sufficient to induce in vitro a significant radiosensitizing effect, the cellular uptake by macropinocytosis leads to a successful radiotherapy in a limited range of particles incubation concentration. Macropinocytosis processes in two steps: formation of agglomerates at vicinity of the cell followed by their collect via the lamellipodia (i.e. the “arms”) of the cell. The first step is strongly dependent on the physicochemical characteristics of the particles, especially their zeta potential that determines the size of the agglomerates and their distance from the cell. These results should permit to control the quantity of particles internalized in the cell cytoplasm, promising ambitious opportunities towards a particle-assisted radiotherapy using lower radiation doses

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Bücher zum Thema "Scanning electron microscopy (MEB)"

Reimer, Ludwig. Scanning Electron Microscopy. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-662-13562-4.

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Reimer, Ludwig. Scanning Electron Microscopy. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-540-38967-5.

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International, Scanning Microscopy. Scanning microscopy. Chicago: Scanning Microscopy International, 1987.

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Pennycook, Stephen J., und Peter D. Nellist, Hrsg. Scanning Transmission Electron Microscopy. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-7200-2.

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M, Prutton, und El Gomati Mohamed M, Hrsg. Scanning Auger electron microscopy. Hoboken, NJ: Wiley, 2006.

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Brodusch, Nicolas, Hendrix Demers und Raynald Gauvin. Field Emission Scanning Electron Microscopy. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-4433-5.

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L, Olsen Sandra, Hrsg. Scanning electron microscopy in archaeology. Oxford, England: B.A.R., 1988.

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Lyman, Charles E., Joseph I. Goldstein, Alton D. Romig, Patrick Echlin, David C. Joy, Dale E. Newbury, David B. Williams et al. Scanning Electron Microscopy, X-Ray Microanalysis, and Analytical Electron Microscopy. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4613-0635-1.

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Kassing, R. Scanning Microscopy: Symposium Proceedings. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992.

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Johari, Om. Scanning electron microscopy/1986: An international journal of scanning electron microscopy, related techniques, and applications. Herausgegeben von Becker Robert P, Levenson L. L, Roomans Godfried M und Scanning Electron Microscopy Inc. [Elk Grove Village, IL]: Scanning Electron Microscopy, 1986.

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Buchteile zum Thema "Scanning electron microscopy (MEB)"

Baumeister, Martin, und Thomas Kohnen. „Scanning Electron Microscopy“. In Encyclopedia of Ophthalmology, 1–2. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-642-35951-4_420-3.

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Zhu, Yimei, und Hiromi Inada. „Scanning Electron Microscopy“. In Encyclopedia of Nanotechnology, 1–10. Dordrecht: Springer Netherlands, 2015. http://dx.doi.org/10.1007/978-94-007-6178-0_110-2.

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Montaña, Ana Vicente, Alfredo Fernández Larios und Alfonso Rodríguez Muñoz. „Scanning Electron Microscopy“. In Atlas of Functional Anatomy for Regional Anesthesia and Pain Medicine, 905–14. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-09522-6_49.

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Han, Wei, Huisheng Jiao und Daniel Fox. „Scanning Electron Microscopy“. In Springer Tracts in Modern Physics, 35–68. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-0454-5_2.

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Erdman, Natasha, David C. Bell und Rudolf Reichelt. „Scanning Electron Microscopy“. In Springer Handbook of Microscopy, 229–318. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-00069-1_5.

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Zhu, Yimei, und Hiromi Inada. „Scanning Electron Microscopy“. In Encyclopedia of Nanotechnology, 3499–507. Dordrecht: Springer Netherlands, 2016. http://dx.doi.org/10.1007/978-94-017-9780-1_110.

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Okano, Yasuyuki. „Scanning Electron Microscopy“. In Compendium of Surface and Interface Analysis, 563–69. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-6156-1_91.

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Wang, Yi, und Vania Petrova. „Scanning Electron Microscopy“. In Nanotechnology Research Methods for Foods and Bioproducts, 103–26. Oxford, UK: Wiley-Blackwell, 2012. http://dx.doi.org/10.1002/9781118229347.ch6.

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Baumeister, Martin, und Thomas Kohnen. „Scanning Electron Microscopy“. In Encyclopedia of Ophthalmology, 1581–82. Berlin, Heidelberg: Springer Berlin Heidelberg, 2018. http://dx.doi.org/10.1007/978-3-540-69000-9_420.

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Zhu, Yimei, Hiromi Inada, Achim Hartschuh, Li Shi, Ada Della Pia, Giovanni Costantini, Amadeo L. Vázquez de Parga et al. „Scanning Electron Microscopy“. In Encyclopedia of Nanotechnology, 2273–80. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-90-481-9751-4_110.

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Konferenzberichte zum Thema "Scanning electron microscopy (MEB)"

Lv, H. P., J. Wang, C. S. Zhai, F. Li und B. D. Sun. „Study of Microstructure, Vickers Microindentation and Microhardness Distribution of HVOF Sprayed Composite MoB/CoCr Coating“. In ITSC2007, herausgegeben von B. R. Marple, M. M. Hyland, Y. C. Lau, C. J. Li, R. S. Lima und G. Montavon. ASM International, 2007. http://dx.doi.org/10.31399/asm.cp.itsc2007p0528.

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Abstract Thermal spray coatings of new MoB/CoCr cermets were developed. The mechanical behavior of HVOF-sprayed MoB/CoCr novel composite coatings was evaluated via Vickers microhardness. Microstructure of the coatings on 316L stainless steel substrates, as well as powders, were studied with optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD). X-ray microanalysis of the coatings was carried out using energy dispersive X-ray spectrometer (EDS) attached to the SEM. The distributions of microhardness values of the coatings were analyzed via Weibull statistic. Weibull analysis revealed a bimodal distribution of Vickers microhardness values. Such distribution was attributed to the presence of melted and unmelted phases in the resultant coating produced from the microstructured powder feedstock. The excellent mechanical properties of the coating are due to the MoB/CoCr powder, which results in the formation of complex ternary transition metal boride hard particles that exhibit exceptional mechanical properties.

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Lipschutz, M., R. Brannam und T. Nguyentat. „Failure Analysis of a Qualification Unit Injector for a Satellite Thruster“. In ISTFA 1998. ASM International, 1998. http://dx.doi.org/10.31399/asm.cp.istfa1998p0083.

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Abstract This article details the results of a failure analysis performed on a Qualification Unit injector for a military satellite thrusters and explains that the failure was initially detected due to a shift in performance during qualification testing. Failure analysis involved non-destructive evaluation on the injector using micro-focus X-ray and scanning electron microscopy. Serial cross-sectional metallography was then performed, with each cross-section documented by optical microscopy and SEM. The failure analysis resulted in three main conclusions: (1) the root cause of the failure was attributed to multiple detonations in or around the damaged orifice; these detonations were likely caused by fuel and/or combustion products condensing in the orifice between pulses and then igniting during a subsequent pulse; (2) multiple damage mechanisms were identified in addition to the ZOT detonations; and (3) the material and platelet manufacturing process met all design parameters.

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Adhi, K. P., R. L. Owings, T. A. Railkar, W. D. Brown und A. P. Malshe. „Femtosecond Excimer (248 NM) Laser Micro-Machining of Teflon (PTFE)“. In ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/med-23344.

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Abstract We have investigated, using X-ray photoelectron spectroscopy (XPS), the surface of polyterafluoroethylene (PTFE) films which were subjected to micromachining by femtosecond UV radiation from an excimer laser (KrF: λ = 248 nm, tp ∼ 380 fs) in air ambient. Bulk characterization of processed PTFE films by Fourier transform infrared spectroscopy (FTIR) allowed us to study laser-induced modifications of the material at energy densities below the ablation threshold. No features in the XPS or FTIR spectra indicated incorporation of hydrogen and/or oxygen or the formation of cross-linked networks of carbon, indicating chemically clean processing in contrast to nanosecond excimer laser processing which chemically degrades the surface being machined. Scanning electron microscopy (SEM) of micrometer size microvias indicates mechanically and thermally damage-free processing of PTFE with good edge quality, again in contrast to nanosecond excimer laser processing.

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Matsui, Y., T. Suzuki, P. Deevanhxay, S. Tsushima und S. Hirai. „Crack Generation in Catalyst Layer and Micro Porous Layer by Wet-Dry Cycles and its Impact on PEMFC Performance“. In ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology collocated with the ASME 2013 Heat Transfer Summer Conference and the ASME 2013 7th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/fuelcell2013-18099.

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In this study, we focused on nano- and micro-scale cracks in the catalyst layer and the micro porous layer of polymer electrolyte membrane fuel cells (PEMFCs) and its impact on cell performance. We applied wet-dry cycles to a conventional test cell to investigate crack generation in the catalyst layer and the micro porous layer. Wet-dry cycles, in which cell temperature was kept at 353K with high- and low-humidified gas alternately applied to the cell, potentially induced mechanical stress to a membrane electrode assembly (MEA) due to membrane hydration and dehydration. As a result, significant degradation of performance was found after the wet-dry cycles. We performed cross-sectional analysis of MEA by using a cross-sectional polisher (CP) and scanning electron microscopy (SEM) to investigate nano- and micro-scale crack generated by the wet-dry cycles in the MEA. The SEM images showed that nano- and micro-scale cracks were significantly generated in the catalyst layer as well as in the micro porous layer after the cycles. We identified cracks in the MEA with different morphologies according to the SEM images, hence, through-plane cracks and in-plane cracks. Through-plane cracks have a deep-valley structure in the MEA while in-plane cracks are formed in an interfacial region between the catalyst layer and the micro porous layer. In-plane cracks could be generated by detachment of the catalyst layer from the micro porous layer due to the wet-dry cycles and potentially decrease in cell performance due to deterioration of electron transport in the MEA. In addition, in case liquid water is accumulated in in-plane cracks, these cracks potentially disturb gas diffusion from the micro porous layer to the catalyst layer. These results clearly showed that mechanical stress induced crack generation in the MEA, resulting in intensive effects on cell performance in PEMFC.

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Cheng, Gary J., Daniel Pirzada, Pankaj Trivedi und David Field. „Effect of Film Thickness and Laser Energy Density on the Structural Characteristics of Laser-Annealed Polycrystalline Gallium Arsenide Films“. In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-16247.

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Scanning electron microscopy and high-resolution electron backscatter diffraction (EBSD) have been used to study the texture and microstructure evolution during the crystallization of initially amorphous GaAs thin films. A KrF excimer laser, with 30 ns pulse duration was used for crystallization of a-GaAs grown on SiO2 Substrate using molecular beam epitaxy (MBE) technique. The effect of laser energy density and film thickness on grain morphology has been studied. The integrated information on grain size distribution, preferred orientation, and nature of grain boundaries provides useful information to postulate the mechanism of grain-growth and likely role of different contributing parameters in the evolution of final texture under the highly transient processing conditions prevailing during the short laser irradiation. The results show that for thick films the laser crystallization results in a weak <111> fiber texture. While for a thinner films the grains have a strong <001> texture that strengthens with a decrease in film thickness and increase in laser energy density.

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Bonnet, P., S. Abboudl und B. Normand. „Study of Damage Processes in Plasma Sprayed Bond Coat Under Thermal Cycling“. In ITSC 1998, herausgegeben von Christian Coddet. ASM International, 1998. http://dx.doi.org/10.31399/asm.cp.itsc1998p1607.

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Abstract Plasma sprayed thermal barriers are used as insulating materials in the hot sections of gas turbines to decrease the metal temperatures during service and men allow a higher combustion temperature for better engine efficiency. They usually contain a bond coating to protect the substrate from high temperature oxidation and a top coat with a low thermal conductivity. This study evaluate and identify the mechanisms of degradation of a vacuum plasma sprayed NiCoCrAlYTa bond coat subjected to thermal cycling at high temperature. The microstructure and micro-composition of the coating layer were analyzed by scanning electron microscopy and energy dispersive X-ray analysis to elucidate the improvement and degradation mechanisms of the material. The thermal cycling provokes some morphological and chemical modifications changes within this material. These modifications provoke a perturbation of the heat transfer within the material.

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Rad, Leili Baghaei, Hanying Feng, Jun Ye, R. F. W. Pease, David G. Seiler, Alain C. Diebold, Robert McDonald et al. „Computational Scanning Electron Microscopy“. In CHARACTERIZATION AND METROLOGY FOR NANOELECTRONICS: 2007 International Conference on Frontiers of Characterization and Metrology. AIP, 2007. http://dx.doi.org/10.1063/1.2799427.

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Galand, R., L. Clément, P. Waltz und Y. Wouters. „Microstructure and texture analysis of advanced copper using electron backscattered diffraction and scanning transmission electron microscopy“. In Scanning Microscopy 2010, herausgegeben von Michael T. Postek, Dale E. Newbury, S. Frank Platek und David C. Joy. SPIE, 2010. http://dx.doi.org/10.1117/12.852908.

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Campo, E. M., H. Campanella, Y. Y. Huang, K. Zinoviev, N. Torras, C. Tamargo, D. Yates, L. Rotkina, J. Esteve und E. M. Terentjev. „Electron microscopy of polymer-carbon nanotubes composites“. In Scanning Microscopy 2010, herausgegeben von Michael T. Postek, Dale E. Newbury, S. Frank Platek und David C. Joy. SPIE, 2010. http://dx.doi.org/10.1117/12.867718.

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Haque, Mohammad Shafinul, Edel Arrieta, Jorge Mireles, Cesar Carrasco, Calvin M. Stewart und Ryan B. Wicker. „Mechanical Behavior and Microstructure of Electron Beam Melted Ti-6Al-4V Using Digital Image Correlation“. In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-66178.

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The reputation of additive manufacturing technology has increased dramatically in recent years due to its freedom of design, customization, and waste minimization. The growing demand for complex profile components to achieve more economic and strength-to-weight efficient aero-engine components can be met by additive manufacturing technology. In this study, electron beam melting (EBM), a powder bed additive layer manufacturing process, is used to manufacture Ti-6Al-4V tensile specimens. The Ti-6AL-4V alloy has excellent corrosion and high temperature resistance with a high strength-to-weight ratio. It is widely used in the power generation, aerospace, and medical industries. An Arcam Ti-6Al-4V prealloyed powder with particle sizes ranging from 45μ–100μ is used in an Arcam A2 machine to manufacture three specimens at zero degree manufacturing orientation. The zero degree manufacturing orientation is expected to exhibit a higher strength over other orientations. The EBM manufacturing parameters were set at 15mA current and 4530 mm/sec beam speed. Tensile tests were performed at room temperature (25.5°C) under a strain rate of 0.003 mm/mm/min according to the ASTM E8 standard for strain-rate sensitive materials. Stress-strain curves are plotted and discussed. Tensile test results indicate a tensile strength of 1.2 GPa and an elongation of 8% approximately. Three Dimensional Digital Image Correlation (3D-DIC) is used to measure the full strain field and deformation evolution on the surface of the specimens. The 3D-DIC system compares digital photographs (taken at two different angles simultaneously) of the surface of a specimen and calculates the deformation and strain fields. Using the strain fields the mechanical properties are determined by the relationships in the strain tensor. The tensile test results show that for a zero degree manufacturing orientation, the yield strength (YS) and ultimate tensile strength (UTS) are higher than that typically reported for wrought products. Fractography using optical microscopy (OM) and Scanning Electron Microscopy (SEM) were conducted. Micrographs of transverse section of the specimen were obtained to identify and analyze the failure mechanism that took place during testing. The built direction, presence of voids, manufacturing defects, and unmelted particles are observed from the SEM views. Surface roughness and microstructure were observed in the OM. A comparison of the obtained results with the literature for additively manufactured Ti-6Al-4V and possible causes are discussed.

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Berichte der Organisationen zum Thema "Scanning electron microscopy (MEB)"

Weber, Peter M. Time-Resolved Scanning Electron Microscopy. Fort Belvoir, VA: Defense Technical Information Center, Juni 2006. http://dx.doi.org/10.21236/ada455461.

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Pennycook, S. J., und A. R. Lupini. Image Resolution in Scanning Transmission Electron Microscopy. Office of Scientific and Technical Information (OSTI), Juni 2008. http://dx.doi.org/10.2172/939888.

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Bertness, K. A. Dimensional measurement of nanostructures with scanning electron microscopy. Gaithersburg, MD: National Institute of Standards and Technology, September 2017. http://dx.doi.org/10.6028/nist.sp.250-96.

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Nakakura, Craig Y., und Kimberlee Chiyoko Celio. Novel Applications of Scanning Ultrafast Electron Microscopy (SUEM). Office of Scientific and Technical Information (OSTI), September 2019. http://dx.doi.org/10.2172/1564040.

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Mikula, R. J. Application of scanning electron microscopy to tar sands emulsions. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1986. http://dx.doi.org/10.4095/304896.

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Stutzman, Paul E. Serial sectioning of hardened cement paste for scanning electron microscopy. Gaithersburg, MD: National Institute of Standards and Technology, 1990. http://dx.doi.org/10.6028/nist.ir.90-4235.

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Dordević, Milena, Radoslav Cerović, Dragan Nikolić, Sanja Radičević, Ivana Glišić und Nebojša Milošević. Using Scanning Electron Microscopy to Characterise Plum (Prunus domestica L.) Genotypes. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, Oktober 2020. http://dx.doi.org/10.7546/crabs.2020.10.08.

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Coleman, R. V. Surface structure and analysis with scanning tunneling microscopy and electron tunneling spectroscopy. Office of Scientific and Technical Information (OSTI), Januar 1992. http://dx.doi.org/10.2172/6017304.

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Prabhakaran, Ramprashad, Vineet V. Joshi, Mark A. Rhodes, Alan L. Schemer-Kohrn, Anthony D. Guzman und Curt A. Lavender. U-10Mo Sample Preparation and Examination using Optical and Scanning Electron Microscopy. Office of Scientific and Technical Information (OSTI), März 2016. http://dx.doi.org/10.2172/1339911.

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