Articoli di riviste: "In situ SEM characterization"

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Lupinacci, A., P. Hosemann, A. Minor e A. Shapiro. "In-Situ SEM Characterization of Fracture Behavior". Microscopy and Microanalysis 18, S2 (luglio 2012): 792–93. http://dx.doi.org/10.1017/s1431927612005818.

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Qu, Juntian, e Xinyu Liu. "Recent Advances on SEM-Based In Situ Multiphysical Characterization of Nanomaterials". Scanning 2021 (9 giugno 2021): 1–16. http://dx.doi.org/10.1155/2021/4426254.

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Abstract (sommario):

Functional nanomaterials possess exceptional mechanical, electrical, and optical properties which have significantly benefited their diverse applications to a variety of scientific and engineering problems. In order to fully understand their characteristics and further guide their synthesis and device application, the multiphysical properties of these nanomaterials need to be characterized accurately and efficiently. Among various experimental tools for nanomaterial characterization, scanning electron microscopy- (SEM-) based platforms provide merits of high imaging resolution, accuracy and stability, well-controlled testing conditions, and the compatibility with other high-resolution material characterization techniques (e.g., atomic force microscopy), thus, various SEM-enabled techniques have been well developed for characterizing the multiphysical properties of nanomaterials. In this review, we summarize existing SEM-based platforms for nanomaterial multiphysical (mechanical, electrical, and electromechanical) in situ characterization, outline critical experimental challenges for nanomaterial optical characterization in SEM, and discuss potential demands of the SEM-based platforms to characterizing multiphysical properties of the nanomaterials.

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Antoniou, Nicholas, Konrad Rykaczewski e Michael D. Uchic. "In situ FIB-SEM characterization and manipulation methods". MRS Bulletin 39, n. 4 (aprile 2014): 347–52. http://dx.doi.org/10.1557/mrs.2014.58.

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Lu, Yang, Yajing Shen, Xinyu Liu, Mohd Ridzuan Bin Ahmad e Yan Chen. "In Situ SEM Nanomanipulation and Nanomechanical/Electrical Characterization". Scanning 2017 (2017): 1–2. http://dx.doi.org/10.1155/2017/8016571.

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Gan, Meixue, Lang Tian, Yiruo Chen, Jieting Xin, Hui Si, Yimin Xie e Qinghua Feng. "All-cellulose composites fabricated by in-situ welding". BioResources 18, n. 2 (6 marzo 2023): 3044–55. http://dx.doi.org/10.15376/biores.18.2.3044-3055.

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As a consequence of increasingly serious environmental problems, many researchers are highlighting biomass materials. Cellulose, the most abundant bioresource, is becoming a key consideration for alleviating environmental pollution. Characterization of cellulosic materials is fundamental to exploring their structures and elemental contents. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) are frequently employed to study the structure of cellulose. Thus, it is urgent to combine traditional means with new ones. This study focused on the characterization of the all-cellulose composites (ACCs) model prepared via partially dissolving filter paper using 40% benzyltrimethylammonium hydroxide (BzMe3NOH) aqueous solution. Characterized by SEM, XRD, Fourier transformation infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy, the unique transformation from cellulose I to cellulose II of the ACCs model was explored. These characterization methods exhibited respective features, which could be universal ways to investigate ACCs.

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Gauvin, Raynald, Karim Zaghib, Nicolas Brodusch, Maryam Golozar e Nicolas Dumaresq. "In-Situ Characterization of Lithium Ion Batteries in the SEM". ECS Meeting Abstracts MA2022-02, n. 7 (9 ottobre 2022): 2433. http://dx.doi.org/10.1149/ma2022-0272433mtgabs.

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This paper will present state of the art characterization of Lithium Ion Batteries usimg low voltage EELS and EDS of Li using the SU-9000 STEM from Hitachi working at 30 keV and 3 keV. Extensive in-situ work in SEM of LIB made with Li anodes will also be presented.

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Jiang, Chenchen, Haojian Lu, Hongti Zhang, Yajing Shen e Yang Lu. "Recent Advances on In Situ SEM Mechanical and Electrical Characterization of Low-Dimensional Nanomaterials". Scanning 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/1985149.

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In the past decades, in situ scanning electron microscopy (SEM) has become a powerful technique for the experimental study of low-dimensional (1D/2D) nanomaterials, since it can provide unprecedented details for individual nanostructures upon mechanical and electrical stimulus and thus uncover the fundamental deformation and failure mechanisms for their device applications. In this overview, we summarized recent developments on in situ SEM-based mechanical and electrical characterization techniques including tensile, compression, bending, and electrical property probing on individual nanostructures, as well as the state-of-the-art electromechanical coupling analysis. In addition, the advantages and disadvantages of in situ SEM tests were also discussed with some possible solutions to address the challenges. Furthermore, critical challenges were also discussed for the development and design of robust in situ SEM characterization platform with higher resolution and wider range of samples. These experimental efforts have offered in-depth understanding on the mechanical and electrical properties of low-dimensional nanomaterial components and given guidelines for their further structural and functional applications.

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Laval, J. Y., M. H. Berger e C. Cabanel. "In Situ Electrical and Microstructural Characterization of Individual Boundaries". Proceedings, annual meeting, Electron Microscopy Society of America 54 (11 agosto 1996): 336–37. http://dx.doi.org/10.1017/s0424820100164143.

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In order to get direct information on the relationships between the structural and electrical properties of interfaces, we developed in situ experiments in TEM-STEM and SEM for the characterization of the local behaviour of majority and minority carriers. In particular, we described here our new technique for local determination of interfacial potential barriers in electronic ceramics. This information is completed by voltage contrast imaging in SEM at 1 kV which enables a full map of the distribution of these interfacial barriers to be obtained.The TEM experiment is schematized in fig. 1. A tungsten microelectrode (100 nm diameter) can be micromanipulated in situ and gently set down on the TEM sample. The contact between the microelectrode and the sample is shown sharply by the modification of extinction contours in each adjacent grain (Fig. 2ab).

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Kim, Jeong Guk. "Analysis of Heat Generation during Fracture in Ceramic Matrix Composites". Key Engineering Materials 385-387 (luglio 2008): 689–92. http://dx.doi.org/10.4028/www.scientific.net/kem.385-387.689.

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Ceramic matrix composites (CMCs) have evolved as potential candidate materials for high-temperature structural applications due to lightweight, high-temperature strength and excellent corrosion and wear resistance. In this investigation, damage evolution and heat generation of CMCs during monotonic loadings were investigated using different types of nondestructive evaluation (NDE) techniques, such as acoustic emission (AE) and infrared (IR) thermography and microstructural characterization. IR camera was used for in-situ monitoring of temperature evolution, and the temperature changes during testing were measured. A significant temperature increase has been observed at the time of failure. Microstructural characterizations using scanning electron microscopy (SEM) were performed to investigate fracture behavior of CMC samples. In this investigation, the NDE technique and SEM characterization were employed to analyze damage evolution and progress of ceramic matrix composites during monotonic loading.

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Weiland, H., D. P. Field e B. L. Adams. "In situ observation of orientation changes on metallic surfaces". Proceedings, annual meeting, Electron Microscopy Society of America 53 (13 agosto 1995): 246–47. http://dx.doi.org/10.1017/s0424820100137604.

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The characterization of crystalline aggregates by the crystallographic orientations of their grains and subgrains has become a subject of increasing interest. The information obtained is not only used for the characterization of materials, but also more importantly for the determination of properties. To mention only a few, applications have been found in the areas of fracture analysis, recrystallization, and plastic deformation.Most commonly, crystallographic orientations are determined from Backscattered Kikuchi Diffraction (BKD) in the SEM and from Kikuchi patterns obtained by microdiffraction in the TEM. Since the development of fully automatic pattern analysis routines for the BKD, the SEM based techniques currently finds the most applications. In conjunction with computer controlled stage or beam displacements, the technique is known as Orientation Imaging Microscopy (OIM). In this manner, thousands of diffraction patterns are analyzed automatically within a short time. This leads to a statistical description of the distribution of crystallographic orientations, which sufficiently represent the bulk material.

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Mrunalini, Phalak, Rajendra Waghulade e Yogesh Toda. "Synthesis and Characterization of Polypyrrole (PPy) by In-situ Polymerization Technique". Journal of Advanced Chemical Sciences 6, n. 2 (9 settembre 2020): 686–88. http://dx.doi.org/10.30799/jacs.224.20060203.

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This work reports synthesize of polypyrrole nano powder by chemical in-situ polymerization of pyrrole in aqueous solution and ammonium persulfate solution which acts as oxidant. It is characterized by X-ray diffraction (XRD), Fourier infra-red spectroscopy (FTIR) and scanning electron microscopy (SEM). The XRD spectrum reveals that the materials are amorphous in nature. FTIR analysis confirms that all peaks are the main characteristic of PPy. SEM analysis showed that the powder has a uniform granular morphology and the size varies from ∼500 nm to 1 μm. The micrograph of polypyrrole reveals the presence of globular particles. The formed particles are irregular in nature. The results show that the fibers are chemically formed as spherical nanostructures.

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Kim, Jeongguk, e Peter K. Liaw. "Characterization of Fatigue Damage Modes in Nicalon/Calcium Aluminosilicate Composites". Journal of Engineering Materials and Technology 127, n. 1 (1 gennaio 2005): 8–15. http://dx.doi.org/10.1115/1.1836766.

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High-cycle fatigue behavior of Nicalon™ fiber-reinforced calcium aluminosilicate (CAS) glass–ceramic matrix composites (Nicalon™/CAS) was investigated with the aid of a nondestructive evaluation (NDE) technique. Infrared (IR) thermography was employed to study two different types of Nicalon™/CAS composites: crossply and unidirectional specimens. During fatigue testing, an IR camera was used for in-situ monitoring of temperature evolution of Nicalon™/CAS samples. Stress versus cycles to failure curves were generated for predicting the lifetime of Nicalon™/CAS composites, and the IR camera measured the temperature changes during high-cycle fatigue testing. Microstructural characterizations using scanning electron microscopy (SEM) were performed to investigate fracture modes and failure mechanisms of Nicalon™/CAS samples. In this study, the NDE technique and SEM characterization were used to facilitate a better understanding of damage evolution and progress of Nicalon™/CAS composites during high-cycle fatigue.

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Huang, Qing, Guojin Zheng e Tian Wu. "Surface nitridation of Ta powder by molten-salt electrolysis of Ta2O5 under N2 atmosphere". Functional Materials Letters 13, n. 07 (3 settembre 2020): 2050032. http://dx.doi.org/10.1142/s1793604720500320.

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The electro-deoxidation of Ta2O5 in molten CaCl2 under N2 atmosphere is a facile way for the in situ surface nitridation of Ta particles. The cell voltage and electrolysis time of Ta2O5 are rationalized to realize the in situ surface nitridation of Ta. All the characterization results including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and elements mapping as well as X-ray photoelectron spectroscopy (XPS) confirm the formation of Ta2N layers on the surface of Ta particles, with the thickness of 3–4[Formula: see text]nm. This method provides a strategy for the facile in situ surface nitridation with N2 as the nitrogen source for the fabrication of core-shell structured catalysts.

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Kim, Jeong Guk, e Peter K. Liaw. "Fracture Behavior of Ceramic Matrix Composites during Monotonic and Cyclic Loadings". Key Engineering Materials 345-346 (agosto 2007): 649–52. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.649.

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The fracture behavior of ceramic matrix composites (CMCs) was investigated using the infrared (IR) thermography nondestructive evaluation (NDE) technique during monotonic and cyclic loadings. The CMCs used for this investigation are continuous Nicalon (silicon carbide fiber) fiber reinforced calsium aluminosilicate (CAS) glass-ceramics matrix composites. During monotonic tension and cyclic fatigue loadings, IR camera was used for in-situ monitoring of temperature evolution, and the temperature changes during testing were measured. Microstructural characterizations using scanning electron microscopy (SEM) were performed to investigate fracture modes and failure mechanisms of Nicalon/CAS samples. In this investigation, the NDE technique and SEM characterization were employed to facilitate a better understanding of damage evolution and progress of Nicalon/CAS composites during monotonic and cyclic loadings.

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Mahadevi, V., S. Veeresh, B. T. Vijaykumr, Reshma, Priyanka Kolhar, Bharati Basavaraj e Basavaraja Sannakki. "Situ synthesis and characterization of polypyrrole/ZnO Nanocomposites for optical and photocatalytic activity". IOP Conference Series: Materials Science and Engineering 1300, n. 1 (1 aprile 2024): 012022. http://dx.doi.org/10.1088/1757-899x/1300/1/012022.

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Abstract In situ polymerisation process used for manufacturing polypyrrole (PPy) nanoparticle-reinforced various doping concentration of zinc oxide (ZnO NPs) nanocomposites. Fourier transform infrared(FTIR), Scanning electron microscopy(SEM), Photo luminescence (PL) and UV-vis spectroscopy was used to characterise the polymer nanocomposite. The ZnO nanoparticles are distributed throughout PPy matrix as shown in the SEM pictures of the nanocomposites. Distinctive peaks of Pure PPy and metal oxide bond of ZnO are as displayed in the FTIR spectra. Optical property of PPy, ZnO and PPy/ZnO was studied by using PL and UV-DRs spectrophotometer. These outcomes demonstrated that the synthesised PZ30 nanoparticles could potentially use in the treatment of wastewater.

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Beekman, Pepijn, Agustin Enciso-Martinez, Hoon Suk Rho, Sidharam Pundlik Pujari, Aufried Lenferink, Han Zuilhof, Leon W. M. M. Terstappen, Cees Otto e Séverine Le Gac. "Immuno-capture of extracellular vesicles for individual multi-modal characterization using AFM, SEM and Raman spectroscopy". Lab on a Chip 19, n. 15 (2019): 2526–36. http://dx.doi.org/10.1039/c9lc00081j.

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Here, we report a platform for the specific capture of tdEVs, followed by their in situ characterization using SEM, Raman spectroscopy and AFM, at the single EV level, in terms of size, size distribution and chemical fingerprinting.

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Bessette, Stéphanie, Pierre Hovington, Hendrix Demers, Maryam Golozar, Patrick Bouchard, Raynald Gauvin e Karim Zaghib. "In-Situ Characterization of Lithium Native Passivation Layer in A High Vacuum Scanning Electron Microscope". Microscopy and Microanalysis 25, n. 4 (24 maggio 2019): 866–73. http://dx.doi.org/10.1017/s1431927619000631.

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AbstractA technique to characterize the native passivation layer (NPL) on pure lithium metal foils in a scanning electron microscope (SEM) is described in this paper. Lithium is a very reactive metal, and consequently, observing and quantifying its properties in a SEM is often compromised by rapid oxidation. In this work, a pure lithium energy-dispersive x-ray spectrum is obtained for the first time in a high vacuum SEM using a cold stage/cold trap with liquid nitrogen reservoir outside the SEM chamber. A nanomanipulator (OmniProbe 400) inside the microscope combined with x-ray microanalysis and windowless energy dispersive spectrometer is used to fully characterize the NPL of lithium metal and some of its alloys by a mechanical removal procedure. The results show that the native films of pure lithium and its alloys are composed of a thin (25 nm) outer layer that is carbon-rich and an inner layer containing a significant amount of oxygen. Differences in thickness between laminated and extruded samples are observed and vary depending on the alloy composition.

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Coppola, Sara, Lisa Miccio, Zhe Wang, Giuseppe Nasti, Vincenzo Ferraro, Pier Luca Maffettone, Veronica Vespini, Rachele Castaldo, Gennaro Gentile e Pietro Ferraro. "Instant in situ formation of a polymer film at the water–oil interface". RSC Advances 12, n. 48 (2022): 31215–24. http://dx.doi.org/10.1039/d2ra04300a.

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A completely new method for easy and quick formation of a thin polymer film at the special setting of a stratified oil/water interface. Morphological SEM and quantitative full-field characterization have been reported using digital holography.

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Du, Hanxiao, Juan Ji, Luyi Wang, Chenwei Qin, Ze Zhang, Fengfeng Li e Yi Shen. "Photocatalytic Activity of Ag@AgBr/Ag2CO3 Heterojunction Synthesized by in situ Reduction". Nano 16, n. 08 (luglio 2021): 2150097. http://dx.doi.org/10.1142/s1793292021500971.

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The poor stability of the silver-based semiconductor photocatalyst is an insurmountable problem. Coupling different proportions of AgBr and Ag2CO3 together by in situ reduction method produced a series of novel AgBr/Ag2CO3 composite photocatalysts, and was accompanied by the generation of Ag@AgBr/Ag2CO3 heterojunction. The effects of different ratios of AgBr and Ag2CO3 on the photocatalytic degradation of rhodamine B under visible light irradiation were studied by XRD, UV–Vis DRS, SEM, HRTEM, TEM and XPS characterization techniques. The best ratio and UV irradiation time were explored. In addition, the photocatalytic mechanism of the photocatalyst was described. The Ag NPs formed on the surface of AgBr/Ag2CO3 may be one of the reasons for effectively improving the separation efficiency of electron–hole pairs (e[Formula: see text]h[Formula: see text], accelerating dye degradation and improving photocatalytic stability.

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Xu, Ming Mei, Wang Xiao, Yong Zhu Cui, Wei Shao, Yan Ling Sui e Gil Min Byung. "In Situ Synthesis and Characterization of Nanosize Hydroxyapatite/Polyacrylonitrile Composite Bead". Materials Science Forum 743-744 (gennaio 2013): 486–90. http://dx.doi.org/10.4028/www.scientific.net/msf.743-744.486.

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nanosize hydroxyapatite/polyacrylonitrile composite bead was prepared via in-situ synthesis method. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), particle size measurement and X-ray diffraction (XRD) were used to characterize the HAp/PAN composite bead. XRD curve indicates low crystallinity of HAp. Particle size and SEM analysis demonstrates that decreased partical size of synthesized HAp as well as good distribution with the addition of PAN is found. The HAp is well-distributed and the combination between HAp and PAN is well. FTIR showed that there was no shift of characteristic peaks of synthesized HAp in PAN, which proves the physical interaction between PAN and HAp. The approximate HAp content of 28.6% calculated from thermal analysis curves means high conversion ratio of HAp. The adsorption amount of cadmium ions onto composite beads is lower than HAp particles.

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Auradi, V., S. L. Biradar, S. M. Suresha e S. A. Kori. "Microstructure and Mechanical Characterization of Al-Tib₂In Situ Metal Matrix Composites Produced via Master Alloy Route". Applied Mechanics and Materials 592-594 (luglio 2014): 494–98. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.494.

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In the present work, Al-TiB2in-situ metal matrix composites were processed via master alloy route at 800°C-30 min. with 5 and 7wt% of TiB2particles. Microstructural characterization of the prepared insitu composites were carried out using XRD, SEM/EDX studies. X ray diffraction studies have shown the presence of Al3Ti and TiB2phases, however, the presence of AlB2particles is also highly likely. SEM/EDX characterization revealed fairly uniformly distributed TiB2particles having hexagonal morphology with size distribution in the ranges between 0.5-10μm. Further, presence of TiB2particles in Al matrix have resulted in improvement in hardness and tensile properties of the Al matrix while decrease in ductility was observed.

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Moldovan, Grigore, Florian Schumann, Wolfgang Joachimi e Marc Willinger. "Characterization of Electrode-based BackScatter Electron Detector for In Situ SEM". Microscopy and Microanalysis 29, Supplement_1 (22 luglio 2023): 2083–84. http://dx.doi.org/10.1093/micmic/ozad067.1078.

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Alipour, A., K. T. Arat, H. Alemansour, L. Montes, J. Gardiner, J. Diederichs, B. Colvin et al. "A Highly Integrated AFM-SEM Correlative Analysis Platform". Microscopy Today 31, n. 6 (novembre 2023): 17–22. http://dx.doi.org/10.1093/mictod/qaad083.

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Abstract We describe the first truly correlative atomic force microscopy-scanning electron microscopy (AFM-SEM) platform designed from first principles and from the ground up for the study of sample properties under a wide range of magnifications. Combining these two microscopy techniques, “in situ,” into a highly integrated workstation opens unprecedented measurement capabilities at the nanoscale, while simplifying experiment workflows to yield a higher level of data throughput. Unlike SEM, the AFM offers true three-dimensional topography images, something SEM can only provide indirectly. This allows for the characterization of nano-mechanical properties, as well as for magnetic and electrical characterization of samples, which are increasingly of interest in material science, multi-component technologies (that is, solar cell and battery research), and pharmaceutical investigations. On the other hand, the SEM’s wide field-of-view is critical in identifying regions of interest with feature sizes of less than a micron, which are notoriously difficult to find over large spatial scales in conventional AFM systems. In addition, the SEM’s ability to visualize the AFM tip facilitates its navigation to aid the characterization of samples with challenging three-dimensional topographies. In this paper, we describe the major elements of the system design and demonstrate how correlative microscopy can help the characterization of samples with challenging morphologies such as the edge of a razor blade or the nanomechanical analysis of platinum nanopillars.

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Ding, Chunyue, Xueren Qian, Jing Shen e Xianhui An. "Preparation and characterization of conductive paper via in-situ polymerization of pyrrole". BioResources 5, n. 1 (24 dicembre 2009): 303–15. http://dx.doi.org/10.15376/biores.5.1.303-315.

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Electrically conductive paper was prepared via in-situ chemical oxidative polymerization of pyrrole by using ferric chloride as an oxidant and p-toluenesulfonic acid (PTSA) as a dopant. The deposition of polypyrrole (PPy) on the fiber surface was verified by ATR-FTIR and SEM analyses. Pyrrole concentration had a significant effect on the surface resistivity of conductive paper, especially when the pyrrole concentration was less than 1.8 g·L-1. The conductivity of the PPy-coated paper could be controlled by adjusting pyrrole concentration. The threshold concen-tration of pyrrole was 1.2 g·L-1 when the molar ratio of dopant to pyrrole was 2:1. Very little polymerization reaction in solution occurred when pyrrole concentration was less than 2.5 g·L-1. The pyrrole concentration should reach a higher value to prepare a relatively stable conductive paper with lower resistivity. The XPS results showed that the amount of the PPy coating increased, while the doping level first decreased then increased with the increase of pyrrole concentration. The SEM-EDXA results showed that there was no difference in the amount of PPy coated between the outer surface and the internal wall, but the doping level of the outer surface was higher than that of the internal wall.

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Kaymakci, Orkun, e Nurseli Uyanik. "In-situ Microfibrillar Recycled PET/Glass Fiber/PP Hybrid Thermoplastic Composites". Materiale Plastice 57, n. 4 (6 gennaio 2021): 309–16. http://dx.doi.org/10.37358/mp.20.4.5429.

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Hybrid composites of in-situ microfibrillar recycled polyethylene terephthalate (rPET)/glass fiber (GF)/polypropylene (PP) were developed as an economical and environmentally friendly alternative to glass fiber reinforced thermoplastic PP composites. The effect of replacing glass fibers with in-situ formed polymer microfibrils on mechanical and viscoelastic properties of the composites was investigated with tensile, flexural, and dynamic mechanical tests. Characterization results showed that mechanical and viscoelastic performance of 34% glass fiber reinforced PP can be obtained with 24% glass fiber, 10% microfibrillar rPET composites. Compatibilization effect of the maleic anhydride grafted PP (MA-g-PP) was studied using Fourier transform infrared (FTIR) spectroscopy. The scanning electron microscopy (SEM) images confirmed the formation of the rPET microfibrils in the hybrid matrix. Besides, composites with MA-g-PP compatibilizers showed significantly improved fiber-matrix interfacial adhesion on the SEM images.

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Schubert, Michaela, Jaroslaw Kita, Christian Münch e Ralf Moos. "Investigation of the in situ calcination of aerosol co-deposited NiO-Mn2O3 films". Functional Materials Letters 12, n. 03 (16 maggio 2019): 1950039. http://dx.doi.org/10.1142/s1793604719500395.

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An in situ calcination of an aerosol co-deposited (AcD) NiO-Mn2O3 film for the production of a single-phase cubic NiMn2O4 spinel film was investigated. Characterizations of the AcD film were performed before, during, and after calcination using SEM, XRD and electrical measurements. It could be shown that in situ calcination to mechanically stable films with single-phase cubic spinel structure is possible. Furthermore, changes in the crystal structure and the NTCR parameters [Formula: see text] and [Formula: see text] during calcination could be shown. After in situ calcination, the electrical properties are similar to those of conventional bulk ceramics.

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Wang, Xue Bao. "Preparation and Characterization of Thermally Expandable Microcapsules by In Situ Polymerization". Advanced Materials Research 496 (marzo 2012): 130–33. http://dx.doi.org/10.4028/www.scientific.net/amr.496.130.

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In the present work, we synthesized microcapsules with copolymer of acrylonitrile and ethyl acrylate as shell and isooctane as core by in situ polymerization, and then optimized the preparative method. Synthesized microcapsules were characterized by Fourier transform infrared spectroscopy (FTIR),13C nuclear magnetic resonance (13C-NMR), scanning electron microscopy (SEM), particle diameter analysis and thermogravimetry (TG).

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Wei, Tao, Zhi Xiong Huang, Guo Rui Yang e Min Xian Shi. "Preparation and Characterization of Polyaniline/PMN Composite by In Situ Polymerization Method". Advanced Materials Research 66 (aprile 2009): 230–33. http://dx.doi.org/10.4028/www.scientific.net/amr.66.230.

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The PANI/PMN composite was prepared by one-step in-situ polymerization method and was characterized via FT-IR, XRD, SEM and TG. The results indicate that the best reaction conditions of in-situ polymerization are 0°C/24h.The PMN powder are entirely coated with PANI, when composite contains more than 60% PANI by volume. The steric hindrance effect of PMN powder decreases the crystallization degree of PANI which polymerizes on the surface of PMN powder in the process of in-situ polymerization. The main weight loss occurring between 300 and 480°C corresponds to the degradation of the PANI polymer chain.

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Kori, S. A., S. L. Biradar e Virupaxi Auradi. "Synthesis of Al-Al₃Ti In Situ Metal Matrix Composites by Salt Route and Evaluation of their Mechanical Properties". Advanced Materials Research 984-985 (luglio 2014): 280–84. http://dx.doi.org/10.4028/www.scientific.net/amr.984-985.280.

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Current work, aims at preparation and characterization of Al-Al3Ti in-situ metal matrix composites with varying percentage of in-situ Al3Ti (3 and 5%) reinforcement. The composites were prepared by the salt route involving reaction of commercial purity aluminum (99.7%) and potassium titanium flourate halide (K2TiF6) salt at a reaction temperature of 800°C and with 60min. holding time. The prepared composites were subjected to microstructural studies using Scanning Electron Microscope. Further, the work aims at evaluating mechanical properties of the prepared composites as per ASTM standards. Microstructural characterization using SEM revealed blocky morphology of Al3Ti intermetallics with fairly homogeneous distribution. Insitu Al-Al3Ti composites have shown better mechanical properties when compared to the unreinforced Al matrix.

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Wang, Hui’e. "In situ Synthesis of Nickel-Dimethylglyoxime/Black Phosphorus Nanorods for Photocatalytic Hydrogen Production from Water Splitting". Nano 15, n. 10 (29 settembre 2020): 2050125. http://dx.doi.org/10.1142/s1793292020501258.

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Here, a novel material consisting of black phosphorus (BP) and nickel-dimethylglyoxime nanorods was successfully prepared via a facile in situ calcination strategy, which possesses efficient catalytic activity for hydrogen production from water splitting. The reason for this phenomenon was explained by a series of characterization technologies such as SEM, TEM, XRD, UV–Vis, XPS and photoelectrochemical. We demonstrated that the fast e− transport channels were provided by the formed hollow structure of C@Ni-D nanorods, the highly exposed active sites on C@Ni-BP nanorods benefiting from the direct in situ growth of BP, the resulted synergetic effects of C@Ni-D-2 nanorods and BP achieved a better performance of photocatalytic hydrogen production from water splitting. The optimal hydrogen generation of C@Ni-BP-2 nanorods could reach up to 600[Formula: see text][Formula: see text]mol within 180[Formula: see text]min and the rate of hydrogen production did not decrease significantly after four repeated reaction cycles. This work may offer new direction in situ growth of novel catalysts for achieving highly efficient hydrogen production.

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31

Lewis, Brett B., Brittnee A. Mound, Bernadeta Srijanto, Jason D. Fowlkes, George M. Pharr e Philip D. Rack. "Growth and nanomechanical characterization of nanoscale 3D architectures grown via focused electron beam induced deposition". Nanoscale 9, n. 42 (2017): 16349–56. http://dx.doi.org/10.1039/c7nr05274j.

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Nanomechanical measurements of platinum–carbon 3D nanoscale architectures grown via focused electron beam induced deposition (FEBID) were performed using a nanoindentation system in a scanning electron microscope (SEM) for simultaneous in situ imaging.

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32

Moreira, Aida B., Laura M. M. Ribeiro, Pedro Lacerda e Manuel F. Vieira. "Characterization of Iron-Matrix Composites Reinforced by In Situ TiC and Ex Situ WC Fabricated by Casting". Metals 11, n. 6 (25 maggio 2021): 862. http://dx.doi.org/10.3390/met11060862.

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In this study, the effect of microstructural characteristics on the mechanical properties of high-chromium white cast iron-matrix composites reinforced by in situ TiC and ex situ WC was investigated. To this end, two different powder mixtures (Ti + Al + graphite and WC + Fe) were compressed to produce green compacts that were inserted into the mold, before casting. The microstructure of the resulting composites and the base metal was characterized using optical microscopy (OM) and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS). The microstructural analysis revealed a sound bonding between the composite zone and the base metal. The reinforcement with WC particles showed a homogeneous distribution of the carbide particles, unlike the reinforcement with TiC particles. The mechanical properties of the reinforcements were evaluated using hardness and ball-cratering micro-abrasion tests. The results showed that both reinforcements increase the hardness and wear performance of the base material, which was the best performance achieved by the reinforcement with WC particles.

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33

Piticescu, Roxana M., Gabrielle Charlotte Chitanu, Mihaela Albulescu, Maria Giurginca, Madalina Laura Popescu e Witold Łojkowski. "Hybrid HAp-Maleic Anhydride Copolymer Nanocomposites Obtained by In Situ Functionalisation". Solid State Phenomena 106 (settembre 2005): 47–56. http://dx.doi.org/10.4028/www.scientific.net/ssp.106.47.

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The aim of the work is to establish if maleic anhydride copolymer acts as a grain growth modulator and/or as a biocompatible functionalisation agent for hydroxyapatite. Experimental work was developed in three directions: nanocomposites synthesis, nanocomposites characterization and citotoxicity tests on nanocomposites. Maleic anhydride copolymer – HAp nanocomposites were prepared by in situ functionalisation in hydrothermal conditions and were characterized by chemical quantitative analysis, XRD, FT-IR, SEM, specific surface area and picnometric densities. Chemical bonding between the copolymer carboxyl groups and calcium ions of HAp induced a peak of 1577 cm-1 on the FT-IR analysis. Following the evolution of this characteristic peak with the hydrothermal synthesis conditions (different temperatures and pressures) and corroborates the results with XRD and SEM analysis it was pointed out the copolymer grain growth modulator behaviour. Citotoxicity studies in vitro on mice fibroblast cultures were performed. The results proved the biocompatibility of new hybrid –polymer nanocomposites.

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34

Wurster, Roland, Simone Pentzien, Andrea Conradi e Jörg Krüger. "Characterization of Laser-Generated Microparticles by Means of a Dust Monitor and SEM Imaging". Laser Chemistry 2006 (27 dicembre 2006): 1–5. http://dx.doi.org/10.1155/2006/31862.

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Nanosecond laser (1064 nm wavelength) cleaning of artificially soiled paper as a model sample simulating a real-world artwork was performed. During the cleaning process, the ejection of particles was monitored in situ by means of a dust monitor (8 size classes, ranging from 0.3 μm to >2 μm) and ex situ using a mini-cascade impactor (MKI, 5 stages). The cleaning result was analyzed by scanning electron microscopy (SEM) considering possible laser-induced damages to the substrate. Size distributions of emitted particles were measured depending on the processing parameters: laser fluence, F, and pulse number per spot, N. High numbers of large (>2 μm) particles were collected by the mini-cascade impactor indicating a gas dynamical liftoff process. Obviously, these particles were not affected by the laser-matter interaction. The different methods (SEM, MKI, and dust monitor) are compared with respect to their usefulness for a proper interpretation of the cleaning results.

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35

Lim, Sang Kyoo, Won Mi Choi, Hyun Jung Choi, Seong Hui Hong, Sung Ho Hwang, Soon Hyun Kim, Sung Hwan Lee e Kyeong Wung Kim. "Synthesis and Characterization of Poly(Ethylene Terephthalate) /Al₂O₃ Nanocomposites". Advanced Materials Research 717 (luglio 2013): 54–57. http://dx.doi.org/10.4028/www.scientific.net/amr.717.54.

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Poly (ethylene terephthalate)(PET)/Al2O3nanocomposites via in situ polymerization were studied. The nanoparticle loading was varied from 0.3 to 1 wt.%. From the DSC results, no significant differences were recorded for melting temperatures. However, simple added PET/Al2O3nanocomposites slightly changed to the lower melting temperature. Morphology of the nanocomposites has been examined by SEM. From the SEM results revealed that dispersed Al2O3nanoparticles in the EG (ethylene glycol) during the polymerization can be well dispersed in PET matrix.

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36

Lin, P. S. D., E. A. Dobisz, K. Kash, A. Scherer, H. G. Craighead, B. Tell e J. P. Harbison. "Cathodoluminescence for characterization of quantum wires and discs". Proceedings, annual meeting, Electron Microscopy Society of America 45 (agosto 1987): 346–47. http://dx.doi.org/10.1017/s0424820100126524.

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Abstract (sommario):

Detection of cathodoluminescence(CL) in an scanning electron microscope(SEM) is a powerful technique in the study of novel nanometer size structures in semiconductors. In the SEM, the electrons can be focused into a nanometer probe and one can choose to excite either a single structure or multiple structures. Geometric parameters can be measured in-situ from the secondary(or transmitted) electron image. The carrier injection level is uniform and insensitive to adsorbed surface contamination. We demonstrate in this report the potential of CL in the study of nanometer size quantum-well wires and discs.The experimental setup (Fig. 1) includes a scanning electron microscope, a liquid helium cooled cryostat (from Oxford Instruments) which cools both the ellipsoidal mirror and the sample, and an optical spectrometer equipped with a silicon diode array detector controlled by a multi-channel analyzer (TN 1710).

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37

Bui, Hoa, Nguyen Duc Lam, Bui Xuan Khuyen, Bui Son Tung, Man Hoai Nam, Nguyen Thi Ngoc Anh, Do Chi Linh, Duong Thi Huong e Pham Thi San. "Synthesis and characterization of in-situ MoS2-graphene hybrid nanostructured material". Journal of Military Science and Technology, n. 81 (26 agosto 2022): 122–27. http://dx.doi.org/10.54939/1859-1043.j.mst.81.2022.122-127.

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Nowadays, it has been challenging to develop novel techniques and synthesis processes for hybrid two-dimensional materials. Hence, this research presents an innovative technique for the fabrication of MoS2-Graphene (MoS2-Gr) hybrid nanostructured materials. The graphene was effectively generated in-situ and incorporated into the interlayer spacing of MoS2, which was synthesized by using a co-precipitation process with diethyl glycol as the solvent, followed by annealing the as-synthesized MoS2 at 800 oC for two hours in an inert atmosphere. The integrated graphene enhanced the width of MoS2 interlayers, exposing a substantial concentration of active edge sites in the hybrid material, according to SEM, XRD, HR-TEM, and other characterizations. This research might lead to the development of viable hybrid structured materials for various applications. In addition, this study outlines a novel advanced approach for creating hybrid 2D nanostructured materials with superior characteristics.

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38

Schüttoff, Miriam, Christian Wachtel, Florian Wilhelm, Joachim Scholta e Markus Hölzle. "Improved Understanding of PEMFC Stack Durability Testing through Comprehensive In-Situ and Ex-Situ Characterization Techniques". ECS Transactions 114, n. 5 (27 settembre 2024): 655–69. http://dx.doi.org/10.1149/11405.0655ecst.

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Abstract (sommario):

Durability testing of Proton Exchange Membrane Fuel Cells for mobile applications remains a critical challenge. While most academic studies focus on single-cell testing, there are only few publications on stack testing of technical relevant sizes. This study utilizes comprehensive characterization techniques to enhance understanding of PEMFC stack durability, aiming to meet the currently targeted durability targets. A 5,500-hour long-term test, based on the Auto Stack Industry (ASI) test protocol, was performed on a 7-cell short stack of 240 cm² active area. In-situ techniques, such as spatially resolved current density measurement, cyclic voltammetry, and electrochemical impedance spectroscopy, provided real-time degradation insights, while ex-situ methods, including FIB-SEM analysis, infrared thermography or contact angle measurements provided information on material degradation mechanisms. Membrane degradation was found to be negligible. Slight thinning of the cathode indicates carbon corrosion of the catalyst support. Catalyst aging was observed in the form of Pt band formation and Co leaching. Gas diffusion layers showed hydrophobicity loss, and increased resistance in bipolar plates contributed to reduced performance. Our findings demonstrate that PEMFC stacks operated under automotive drive cycle protocols can meet the actual targeted durability objectives. Moreover, it illustrates the degradation phenomena that occur under realistic operating conditions and modes, and how they evolve over the duration of thousands of hours of operation.

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39

Schüttoff, Miriam, Christian Wachtel, Florian Wilhelm, Joachim Scholta e Markus Hölzle. "Improved Understanding of PEMFC Stack Durability Testing through Comprehensive In-Situ and Ex-Situ Characterization Techniques". ECS Transactions 114, n. 5 (27 settembre 2024): 641–55. http://dx.doi.org/10.1149/11405.0641ecst.

Testo completo

Abstract (sommario):

Durability testing of Proton Exchange Membrane Fuel Cells for mobile applications remains a critical challenge. While most academic studies focus on single-cell testing, there are only few publications on stack testing of technical relevant sizes. This study utilizes comprehensive characterization techniques to enhance understanding of PEMFC stack durability, aiming to meet the currently targeted durability targets. A 5,500-hour long-term test, based on the Auto Stack Industry (ASI) test protocol, was performed on a 7-cell short stack of 240 cm² active area. In-situ techniques, such as spatially resolved current density measurement, cyclic voltammetry, and electrochemical impedance spectroscopy, provided real-time degradation insights, while ex-situ methods, including FIB-SEM analysis, infrared thermography or contact angle measurements provided information on material degradation mechanisms. Membrane degradation was found to be negligible. Slight thinning of the cathode indicates carbon corrosion of the catalyst support. Catalyst aging was observed in the form of Pt band formation and Co leaching. Gas diffusion layers showed hydrophobicity loss, and increased resistance in bipolar plates contributed to reduced performance. Our findings demonstrate that PEMFC stacks operated under automotive drive cycle protocols can meet the actual targeted durability objectives. Moreover, it illustrates the degradation phenomena that occur under realistic operating conditions and modes, and how they evolve over the duration of thousands of hours of operation.

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40

Li, Jinze, Tianhong Ma, Xin Liu, Jiawei Xi, Li Deng, Hao Sun, Yanxin Yang e Xiang Li. "A New Method for In-Situ Characterization of Solid-State Batteries Based on Optical Coherence Tomography". Sensors 24, n. 8 (9 aprile 2024): 2392. http://dx.doi.org/10.3390/s24082392.

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Abstract (sommario):

With the in-depth study of solid-state batteries (SSBs), various in situ and ex situ characterization technologies have been widely used to study them. The performance and reliability of SSBs are limited by the formation and evolution of lithium dendrites at the interfaces between solid electrodes and solid electrolytes. We propose a new method based on optical coherence tomography (OCT) for in situ characterization of the internal state of solid-state batteries. OCT is a low-loss, high-resolution, non-invasive imaging technique that can provide real-time monitoring of cross-sectional images of internal structures of SSBs. The morphology, growth, and evolution of lithium dendrites at different stages of cycling under various conditions can be visualized and quantified by OCT. Furthermore, we validate and correlate the OCT results with scanning electron microscopy (SEM) and XPS, proving the accuracy and effectiveness of the OCT characterization method. We reveal the interfacial phenomena and challenges in SSBs and demonstrate the feasibility and advantages of OCT as a powerful tool for in situ and operando imaging of battery interfaces. This study provides new insights into the mechanisms and factors that affect SSB performance, safety, and lifetime, and suggests possible solutions for improvement and application in the field of applied energy.

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41

Sukumaran Suseelammaa, Sreeja Kumari, Uma Thanu Subramonia Pillai, Sujayakumar Prasanth e Bellampettu Chandrasekhar Pai. "Synthesis and Characterization of In Situ AlN Reinforced Magnesium Matrix Composites". Materials Science Forum 710 (gennaio 2012): 377–82. http://dx.doi.org/10.4028/www.scientific.net/msf.710.377.

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Abstract (sommario):

In situ Mg-AlN composite has been synthesized by nitrogen gas bubbling method. The morphology of the particles is found to be hexagonal by SEM. The size of the AlN particles is found to be in the range from nano, submicron to a few microns. XRD analysis of the samples confirms the formation of AlN in the melt. Further, the grain size of the magnesium matrix has been reduced by the presence of AlN particles. Hardness of the composite is significantly increased in the particle rich area due to the presence of hard AlN particles.

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42

Simões, S., R. Calinas, P. J. Ferreira, F. Viana, M. T. Vieira e M. F. Vieira. "TEM and SEM in-situ annealing of nanocrystalline copper thin films". Microscopy and Microanalysis 14, S3 (settembre 2008): 49–52. http://dx.doi.org/10.1017/s1431927608089368.

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Abstract (sommario):

Materials mechanical resistance is known to depend on the size of structural features, accordingly to the familiar HallPetch equation. For the nanometer range of grain sizes, this relationship breaks down and a change of the grain size exponent is needed to satisfy this dependency. Nevertheless, the superior strength of the nanocrystalline material relays on the small dimension of its grains. Characterization of the thermal stability of these materials becomes relevant since a large fraction of atoms are in the grain boundaries and, as a result, its structure posses a large excess of energy that promotes grain growth. Grain growth in nanocrystalline metals has been observed well below the temperatures needed to promote grain growth in coarse grained materials; in some cases, even at room temperature. From this perspective, the study of grain growth in nanocrystalline metals is crucial for the development of new nanocrystalline materials with outstanding mechanical properties. There are many studies that propose models to explain the mechanism of nucleation and growth of annealing twins in F.C.C. materials. In-situ TEM and SEM techniques are invaluable for understanding and characterizing dynamic microstructural changes like nucleation and growth of grains and twins. This is an important observation because twinning affects the properties of materials and so is essential to comprehend the mechanism of twin formation. Other advantage of the in-situ TEM technique is the study of grain growth in ultra fine film with a thickness in the range of 50 to 100 nm. With these techniques, the mechanisms and kinetics of grain growth in nanocrystalline thin films can be observed and studied in real time.

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43

Yan, W., N. Li, J. Tong, G. Liu e J. Xu. "Effect of particle size on the pore characterization and strength of porous cordierite-mullite ceramics prepared by a pore-forming in-situ technique". Science of Sintering 45, n. 2 (2013): 165–72. http://dx.doi.org/10.2298/sos1302165y.

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Abstract (sommario):

The porous cordierite-mullite ceramics were prepared by the pore-forming in-situ technique. The characterizations of porous cordierite-mullite ceramics were determined by an X-ray diffractometer (XRD), a scanning electron microscopy (SEM), and a microscopy measured method, etc., and the effect of particle size on phase composition, pore characterization and strength were investigated. It?s found that particle size affects strongly the formations of cordierite and mullite, and then changes the pore characterization and strength. With the decrease of the particle size, the sintering temperature at which the formations of cordierite and mullite take place extremely fast decreases, the pore size distribution becomes from bi-peak mode to mono-peak mode, the porosity and the median pore size decrease but strength increases. The most opposite mode is the specimen sintered at 1400 ?C from the grinded powder with an average particle size of 10.2 ?m, which consists of cordierite, mullite and minor spinel, and has a high apparent porosity (40 %), a high compressive strength (58.4 MPa), a small median pore size (6.3 ?m) and well-developed necks between particles.

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44

Sun, Xinzhi, e Fanglin Du. "Synthesis, Characterization and Catalytic Properties of Monometal/SiO2 and Bimetal/SiO2 Hollow Spheres with Mesoporous Structure". Nano 12, n. 12 (dicembre 2017): 1750148. http://dx.doi.org/10.1142/s179329201750148x.

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Abstract (sommario):

Monometallic M1(M[Formula: see text] Ni/Cu/Fe/Co) silicates and bimetallic Ni–M2(M[Formula: see text] Cu/Fe/Co) silicates hollow spheres with mesoporous structure and the controllable morphology have been synthesized successfully via one-step sacrificial template method under hydrothermal conditions. The catalysts were obtained by reducing the corresponding silicates in situ under the hydrogen atmosphere at a certain temperature. All the silicates and the catalysts M1/SiO2 and Ni–M2/SiO2 hollow spheres have been characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) and temperature-programmed reduction (TPR) thoroughly and systematically. The morphology and reaction conditions of bimetallic Ni–M2 silicates hollow spheres depend on the second metal M2, which has been verified by SEM, TEM and XRD. From the results, it can be concluded that bimetallic silicates possess better physical properties in favor of the catalytic activity. Bimetallic Ni–M2/SiO2 hollow spheres had higher catalytic property than the monometallic M1/SiO2 and the conversion of nitrobenzene could reach 100% within 3[Formula: see text]h using Ni–Cu/SiO2 and Ni–Fe/SiO2 hollow spheres as catalysts.

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45

Brown, G. M., e J. H. Butler. "A new method for characterization of domain morphology of polymer blends using RuO4 staining and LVSEM". Proceedings, annual meeting, Electron Microscopy Society of America 54 (11 agosto 1996): 190–91. http://dx.doi.org/10.1017/s0424820100163411.

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Abstract (sommario):

Ruthenium tetroxide (RuO4) staining for TEM is a well proven technique for the characterization of crystalline polyolefins. Blend morphology has also been studied using RuO4 staining and SEM and low voltage SEM. A new method has been developed which uses RuO4 staining and LVSEM in the characterization of polyolefin blend morphology, specifically blends of polypropylene modified by the addition of elastomers or plastics. This method is often preferred over TEM for the characterization of blends and is applicable to many problems encountered in commercial and industrial laboratories including the analysis of domain morphology in molded parts, extruded films and fibers, failure analysis, and the analysis of layer morphology in certain coextruded films.Three sample preparation steps are required prior to the LVSEM analysis. (1) The sample face is cryogenically sectioned on a glass knife in the cryomicrotome. (2) This face is stained in RuO4 vapors for 2.5 hours. The staining solution is prepared in situ by a modification of the method of Montezinos.

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46

Xiang, Jiaqi, Qijie Feng, Junchao Cheng, Lei Lu, Junyu Huang e Zhengye Zhong. "Deformation mechanism of neutron irradiated Al-B based on SEM-DIC". MATEC Web of Conferences 355 (2022): 01004. http://dx.doi.org/10.1051/matecconf/202235501004.

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Abstract (sommario):

The electron backscatter diffraction (EBSD) characterization of irradiated Al-B shows that there is a high concentration defect region around the borides. Nanoscale speckle particles were successfully prepared on the surface of Al-B before and after irradiation, and then the mesoscale strain during in-situ deformation was obtained by digital image correlation (DIC) technique. The results shows that slip band bypass such an area through cross slips with slip band deflection. Transmission electron microscopy (TEM) indicates that abundant helium bubbles exist in the deflected slip band area pinning the dislocations.

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47

Maleki, Ali, Hamed Movahed, Parisa Ravaghi e Tooraj Kari. "Facile in situ synthesis and characterization of a novel PANI/Fe3O4/Ag nanocomposite and investigation of catalytic applications". RSC Advances 6, n. 101 (2016): 98777–87. http://dx.doi.org/10.1039/c6ra18185f.

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A novel magnetic hybrid nanocomposite was successfully synthesized via in situ polymerization, well characterized by FT-IR, XRD, EDX and FE-SEM analysis, and its catalytic activity shown in the synthesis of pharmaceutically important pyrans.

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48

Oleshko, V., P. Crozier, R. Cantrell e A. Westwood. "In Situ and Ex Situ Microscopic Study of Propylene Polymerization With Heterogeneous Mgcl2-Supported Ziegler-Natta Catalysts". Microscopy and Microanalysis 6, S2 (agosto 2000): 33–34. http://dx.doi.org/10.1017/s1431927600032657.

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Abstract (sommario):

The large-scale commercial production of polyolefins by catalytic Ziegler-Natta polymerization have stimulated the development of the third, fourth and fifth generation heterogeneous catalysts comprising high surface area defective MgCl2 with TiCl4, electron donors, and AlR3-co-catalysts. In spite of intensive research over the years, the present level of understanding of the catalysts is still incomplete because of their complex composition leading to a multitude of local active site environments. The aim of this work is to provide a new insight into the process via in situ video microscopy of gas phase propylene polymerization over MgCl2-supported Ziegler-Natta catalysts combined with ex situ characterization by light and electron microscopy techniques (SEM, TEM, HRTEM, STEM, PEELS and windowless EDX). Procedures for catalyst synthesis are described elsewhere. The catalysts were stored in a dry box under a He atmosphere (<lppm H2O/O2). Samples were transferred to specimen holders in the dry box and then transferred into the microscopes under high purge N2 conditions to prevent poisoning of the catalysts by air and moisture.

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Geng, Xi, Jieying Jing, Yinjie Cen, Ravindra Datta e Jianyu Liang. "In Situ Synthesis and Characterization of Polyethyleneimine-Modified Carbon Nanotubes Supported PtRu Electrocatalyst for Methanol Oxidation". Journal of Nanomaterials 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/296589.

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Abstract (sommario):

PtRu bimetallic nanoparticles were successfully synthesized on polyethyleneimine- (PEI-) functionalized multiwalled carbon nanotubes (MWCNTs) via an effective and facile polyol reduction approach. Noncovalent surface modification of MWCNTs with PEI was confirmed by FTIR and zeta potential measurements. The morphology, crystalline structure, and composition of the hybrid material were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and energy dispersive X-ray spectroscopy (EDX), respectively. According to SEM and TEM observations, PtRu nanoparticles with narrow size distribution were homogeneously deposited on PEI-MWCNTs. Cyclic voltammetry tests demonstrated that the as-prepared PtRu/PEI-MWCNTs nanocomposite had a large electrochemical surface area and exhibited enhanced electrocatalytic activity towards methanol oxidation in comparison with oxidized MWCNTs as catalyst support. PEI-functionalized CNTs, as useful building blocks for the assembly of Pt-based electrocatalyst, may have great potential for applications such as direct methanol fuel cell (DMFC).

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50

PRASANNA, G. D., e H. S. JAYANNA. "IN SITU SYNTHESIS, CHARACTERIZATION AND FREQUENCY DEPENDENT AC CONDUCTIVITY OF POLYANILINE/CoFe2O4 NANOCOMPOSITES". Journal of Advanced Dielectrics 01, n. 03 (luglio 2011): 357–62. http://dx.doi.org/10.1142/s2010135x11000434.

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The polyaniline (PANI)/ CoFe2O4 nanocomposites were prepared by an In Situ polymerization of aniline in an aqueous solution. The composites were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrum,thermogravimetric analysis (TGA) and scanning electron micrograph (SEM). The AC conductivity and dielectric properties of these composites were investigated in the frequency range 1 kHz–10 MHz at room temperature. The AC conductivity was found to be constant up to 1 MHz and thereafter it increases steeply and it was observed maximum for the PANI with 60 wt% of CoFe2O4 nanocomposite. At lower frequencies the values of dielectric constant is maximum for pure CoFe2O4 nanoparticles.

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