Articles de revues : « Spectroscopies and electron microscopy »

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Russell, Phillip E. « Scanning Electron Microscopy-based sub-micron spectroscopies ». Proceedings, annual meeting, Electron Microscopy Society of America 44 (août 1986) : 748–49. http://dx.doi.org/10.1017/s0424820100145108.

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The scanning electron microscope provides a convenient mechanism for utilizing a sub-micron focused electron probe as a basis for many diverse spectroscopies. While the main use of an SEM is high resolution and/or large depth of field imaging of topographical features, the same system can be used to locate an electron probe, with spot size as small as 1 nm, on a region of interest, and with approiate spectrometers and detectors, sub-micron spectroscopies of the many signals produced by the interaction of the electron beam with the solid sample can be performed. Of the many signals produced in a typical SEM, the following is a review of the ones which have been utilized as the basis of a sub-micron spectroscopy.

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Bell, L. D. « New electron and hole spectroscopies based on ballistic electron emission microscopy ». Journal of Vacuum Science & ; Technology B : Microelectronics and Nanometer Structures 9, n^o 2 (mars 1991) : 594. http://dx.doi.org/10.1116/1.585466.

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Picher, Matthieu, Stefano Mazzucco, Steve Blankenship et Renu Sharma. « Vibrational and optical spectroscopies integrated with environmental transmission electron microscopy ». Ultramicroscopy 150 (mars 2015) : 10–15. http://dx.doi.org/10.1016/j.ultramic.2014.11.023.

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Lallo, James, Tim S. Nunney, Paul Mack, Robin Simpson et Helen Oppong-Mensah. « Correlative Surface Analysis : Combining XPS, Electron Microscopy, and Other Spectroscopies ». Microscopy and Microanalysis 29, Supplement_1 (22 juillet 2023) : 789. http://dx.doi.org/10.1093/micmic/ozad067.392.

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VIJAYALAKSHMI, R., et V. RAJENDRAN. « IMPACT OF SURFACTANTS ON PHYSICAL PROPERTIES OF BaTiO3 NANOPARTICLES ». International Journal of Nanoscience 12, n^o 01 (février 2013) : 1350003. http://dx.doi.org/10.1142/s0219581x13500038.

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Nanocrystalline BaTiO3 particles of about 20–35 nm have been successfully synthesized by using cationic, anionic and nonionic surfactants such as cetyltrimethyl ammonium bromide (CTAB), sodium dodecyl sulphate (SDS) and poly ethylene glycol (PEG) via hydrothermal method. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis absorption spectroscopy and photoluminescence (PL) spectroscopy. The average particle size, measured by powder X-ray diffraction was determined to be 20–35 nm and was confirmed by transmission electron microscopy. Spherical-like morphologies were obtained by scanning electron microscopy (SEM) analysis. Optical properties of products were investigated by ultraviolet-visible (UV-Vis) absorption and PL spectroscopies.

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Parker, Stewart F., Devashibhai Adroja, Mónica Jiménez-Ruiz, Markus Tischer, Konrad Möbus, Stefan D. Wieland et Peter Albers. « Characterisation of the surface of freshly prepared precious metal catalysts ». Physical Chemistry Chemical Physics 18, n^o 26 (2016) : 17196–201. http://dx.doi.org/10.1039/c6cp01027j.

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Freshly prepared precious metal catalysts have been investigated by electron microscopy, X-ray and neutron spectroscopies and computational methods. At least half the surface is metallic with the remainder covered by oxygen, largely as hydroxide.

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Zaluzec, Nestor J., M. Grace Burke, Sarah J. Haigh et Matthew A. Kulzick. « X-ray Energy-Dispersive Spectrometry During In Situ Liquid Cell Studies Using an Analytical Electron Microscope ». Microscopy and Microanalysis 20, n^o 2 (25 février 2014) : 323–29. http://dx.doi.org/10.1017/s1431927614000154.

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AbstractThe use of analytical spectroscopies during scanning/transmission electron microscope (S/TEM) investigations of micro- and nano-scale structures has become a routine technique in the arsenal of tools available to today’s materials researchers. Essential to implementation and successful application of spectroscopy to characterization is the integration of numerous technologies, which include electron optics, specimen holders, and associated detectors. While this combination has been achieved in many instrument configurations, the integration of X-ray energy-dispersive spectroscopy and in situ liquid environmental cells in the S/TEM has to date been elusive. In this work we present the successful incorporation/modifications to a system that achieves this functionality for analytical electron microscopy.

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Polisetti, Sneha, Amber N. Bible, Jennifer L. Morrell-Falvey et Paul W. Bohn. « Raman chemical imaging of the rhizosphere bacterium Pantoea sp. YR343 and its co-culture with Arabidopsis thaliana ». Analyst 141, n^o 7 (2016) : 2175–82. http://dx.doi.org/10.1039/c6an00080k.

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Raman micro-spectroscopy and confocal Raman imaging are used to study the rhizosphere bacterial isolate, Pantoea sp. YR343, and its co-culture with model plant Arabidopsis thaliana by combining enhanced Raman spectroscopies with electron microscopy and principal component analysis.

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Woodward, John T., et Joseph A. N. Zasadzinski. « Observation of ripple conformations of pβ’ phase of dimyristoyl phosphatidylcholine with the scanning tunneling microscope ». Proceedings, annual meeting, Electron Microscopy Society of America 50, n^o 2 (août 1992) : 1134–35. http://dx.doi.org/10.1017/s0424820100130304.

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The Pβ’ or ripple phase of lecithin-water systems was first observed with x-ray diffraction by Tardieu, Luzzati and Reman in the early 1970's. The ripple phase has been observed in numerous studies using x-ray diffraction, freeze-fracture electron microscopy, and other spectroscopies. Electron microscopy on lecidiins far above full hydration showed the existence of a second ripple conformation nearly twice the wavelength of the ripples observed below full hydration leading to the designation of Λ and Λ/2 ripples. Yet none of these measurements have been able to provide a direct unambiguous measurement of the ripple amplitude and conformation. By modifying the technique of freeze-fracture replication to make it compatible with the scanning tunneling microscope (STM) we have observed both the Λ/2 ripple conformation and, for the first time with an STM, the Λ ripple conformation of dimyristoyl phosphatidylcholine (DMPC) in water.

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He, Yong Wu, Yao Bing Yin, Tao Chang, Li Bian, Guang Qing Zhang et Xiao Liang Li. « A Facile Synthesis of La2O3/GO Nanocomposites in N,N-Dimethylformamide with High Dye Degradation Efficiency ». Journal of Nanomaterials 2018 (2018) : 1–5. http://dx.doi.org/10.1155/2018/4128243.

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La2O3/graphene oxide (GO) nanocomposites were simply synthesized from commercially available LaCl3·7H2O and multilayer GO (5–10 layers) in N,N-dimethylformamide (DMF) under reflux condition without extra stabilizer. The characterization results of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectrum (XPS) spectroscopies showed that the crystalline La2O3 nanoparticles were successfully attached on the surface of GO. Moreover, the as-prepared nanocomposites greatly enhanced the degradation efficiency of organic dyes after 15 min under ultrasound irradiation in pure water. The degradation efficiency of the nanocomposites for methylene blue could be over 99%.

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Guzzinati, Giulio, Thomas Altantzis, Maria Batuk, Annick De Backer, Gunnar Lumbeeck, Vahid Samaee, Dmitry Batuk et al. « Recent Advances in Transmission Electron Microscopy for Materials Science at the EMAT Lab of the University of Antwerp ». Materials 11, n^o 8 (28 juillet 2018) : 1304. http://dx.doi.org/10.3390/ma11081304.

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The rapid progress in materials science that enables the design of materials down to the nanoscale also demands characterization techniques able to analyze the materials down to the same scale, such as transmission electron microscopy. As Belgium’s foremost electron microscopy group, among the largest in the world, EMAT is continuously contributing to the development of TEM techniques, such as high-resolution imaging, diffraction, electron tomography, and spectroscopies, with an emphasis on quantification and reproducibility, as well as employing TEM methodology at the highest level to solve real-world materials science problems. The lab’s recent contributions are presented here together with specific case studies in order to highlight the usefulness of TEM to the advancement of materials science.

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Compagnini, G., S. Lombardo, R. Reitano et S. U. Campisano. « Optical and structural properties of semi-insulating polycrystalline silicon thin films ». Journal of Materials Research 10, n^o 4 (avril 1995) : 885–90. http://dx.doi.org/10.1557/jmr.1995.0885.

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Optical properties of semi-insulating polycrystalline silicon (SIPOS) thin films containing 30 at. % oxygen atoms are investigated in the near ultraviolet, visible and infrared region to improve knowledge on the structure and chemical bonding of these mixtures. An effective medium approximation model is used for a microscopic investigation of the oxide species involved as a function of the annealing temperature (600–1200 °C). The results are compared with other optical spectroscopies (infrared and Raman) and with transmission electron microscopy to give a selected picture of the pure and oxide components.

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Mayer, J. « Electron spectroscopic imaging and diffraction : applications II materials science ». Proceedings, annual meeting, Electron Microscopy Society of America 50, n^o 2 (août 1992) : 1198–99. http://dx.doi.org/10.1017/s0424820100130626.

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With imaging energy filters becoming commercially available in transmission electron microscopy many of the limitations of conventional TEM instruments can be overcome. Energy filtered images of diffraction patterns can now be recorded without scanning using efficient parallel (2-dimensional detection. We have evaluated a prototype of the Zeiss EM 912 Omega, the first commercially available electron microscope with integrated imaging Omega energy filter. Combining the capabilities of the imaging spectrometer with the principal operation modes of a TEM gives access to many new qualitative and quantitative techniques in electron microscopy. The basis for all of them is that the filter selecte electrons within a certain energy loss range ΔE1 <ΔE < ΔE2 and images their contribution to an image (electron spectroscopic imaging, ESI) or a diffraction pattern (electron spectroscopic diffraction, ESD) In many applications the filter is only used to remove the inelastically scattered electrons (elastic or zero loss filtering). Furthermore, the electron energy loss spectrum can be magnified and recorded with serial or parallel detection.

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DEY, S. C., et S. S. NATH. « SIZE-DEPENDENT PHOTOLUMINESCENCE AND ELECTROLUMINESCENCE OF COLLOIDAL CdSe QUANTUM DOTS ». International Journal of Nanoscience 12, n^o 02 (avril 2013) : 1350013. http://dx.doi.org/10.1142/s0219581x13500130.

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Here we adopt a convenient green chemical route for synthesis of CdSe quantum dots, their characterization by UV/Vis absorption spectroscopy, X-ray diffraction study and transmission electron microscopy. We carry out photoluminescence and electroluminescence spectroscopy to investigate the variation in electro-optical property with size. By UV/Vis spectroscopy, blue shift is revealed and bandgap is also calculated. X-ray diffraction spectrum reveals cubic structure and transmission electron micrographs show quantum dots of different size distributions (in the range 2–8 nm). Both the luminescence spectroscopies reveal green-orange luminescence depending upon the size distribution and indicate the possibility of using CdSe quantum dots as light emitting devices with better compatibility and faster response.

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Zikeli, Florian, Vittorio Vinciguerra, Anna Rita Taddei, Alessandro D’Annibale, Manuela Romagnoli et Giuseppe Scarascia Mugnozza. « Isolation and characterization of lignin from beech wood and chestnut sawdust for the preparation of lignin nanoparticles (LNPs) from wood industry side-streams ». Holzforschung 72, n^o 11 (27 novembre 2018) : 961–72. http://dx.doi.org/10.1515/hf-2017-0208.

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AbstractLignin was isolated through mild acidolysis from local wood sources such as beech wood and chestnut wood sawdust, a high-volume side product of wood industries. The lignin fractions were characterized by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), Fourier-transform infrared (FTIR), ultraviolet-visible (UV-Vis) and two-dimensional heteronuclear single-quantum correlation nuclear magnetic resonance (2D HSQC NMR) spectroscopies and size exclusion chromatography (SEC). The Klason lignin (KL) content and polysaccharide composition were determined using traditional methods. Lignin nanoparticles (LNPs) were preparedviaa non-solvent method involving dialysis and characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and FTIR and UV-VIS spectroscopies. Semi-porous as well as hollow nanoparticles endowed with a spherical shape were observed. The large majority of the LNPs exhibited an average particle diameter of 90–120 nm. Dynamic light scattering (DLS) analysis showed that both distribution and frequency of dimensional classes of LNPs are clearly affected by the lignin solvent system, i.e. solvent selection governs the size distribution of LNPs.

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Hao, Xiaoyun, Junyan Gong, Lizhen Ren, Dongen Zhang, Xin Xiao, Youxiang Jiang, Fan Zhang et Zhiwei Tong. « Preparation of polyaniline modified BiOBr with enhanced photocatalytic activities ». Functional Materials Letters 10, n^o 04 (août 2017) : 1750040. http://dx.doi.org/10.1142/s1793604717500400.

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The polyaniline/bismuth oxybromide (PANI/BiOBr) hybrids materials have been synthesized hydrothermally in the presence of PANI. The PANI/BiOBr hybrids materials were confirmed by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy and ultraviolet–visible diffuse reflectance spectroscopies. Among the hybrid photocatalysts, PANI/BiOBr-0.2 showed the highest photocatalytic properties for the degradation of rhodamine B (RhB), and the increased photocatalytic properties could be due to photosensitization and the inhibited electron–hole recombination.

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Taha, Amel, et Hanaa A. Hassanin. « Facile Green Synthesis of Ni(OH)2@Mn3O4 Cactus-Type Nanocomposite : Characterization and Cytotoxicity Properties ». Molecules 27, n^o 24 (8 décembre 2022) : 8703. http://dx.doi.org/10.3390/molecules27248703.

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In the present work, the facile eco-friendly synthesis and evaluation of the anti-tumor activity of Ni(OH)2@Mn3O4 nanocomposite were carried out. The synthesis of Ni(OH)2@Mn3O4 nanocomposite from chia-seed extract was mediated by sonication. The obtained materials were characterized by different spectroscopic techniques such as transmission electron microscopy (TEM), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-Vis), and Fourier transform infrared (FT-IR) spectroscopies. The results of XRD, SEM, EDS, TEM, FT-IR, and UV-Vis analysis indicate the successful manufacturing of a crystalline, cactus-type Ni(OH)2@Mn3O4 nanocomposite of 10.10 nm average particle size. XPS analysis confirms that the synthesized materials consist mainly of Ni2+, Mn2+, and Mn3+. The antitumor activity of the nanocomposite was tested against a breast cancer (MCF-7) cell line. The results showed Ni(OH)2@Mn3O4 nanocomposite possesses insignificant cytotoxicity. The cell-death percentage was 34% at a 100 ppm concentration of Ni(OH)2@Mn3O4 nanocomposite. The obtained results imply that the synthesized nanocomposite could be suitable and safe for drug delivery and water treatment.

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Kociak, Mathieu, Odile Stéphan, Alexandre Gloter, Luiz F. Zagonel, Luiz H. G. Tizei, Marcel Tencé, Katia March et al. « Seeing and measuring in colours : Electron microscopy and spectroscopies applied to nano-optics ». Comptes Rendus Physique 15, n^o 2-3 (février 2014) : 158–75. http://dx.doi.org/10.1016/j.crhy.2013.10.003.

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Čeh, M., H. Gu, H. Müllejans et A. Rečnik. « Analytical electron microscopy of planar faults in SrO-doped CaTiO3 ». Journal of Materials Research 12, n^o 9 (septembre 1997) : 2438–46. http://dx.doi.org/10.1557/jmr.1997.0322.

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Oxide-rich planar faults within a perovskite matrix are the prevailing type of extended defects in polycrystalline SrO-doped CaTiO3. These defects form, depending on the temperature of sintering, random networks, or ordered structures. The chemistry of the polytypoid, the isolated planar faults, and the perovskite phase have been studied by spatially resolved electron energy-loss and energy-dispersive x-ray spectroscopies using a dedicated scanning transmission electron microscope. We have found that Sr ions from SrO additions preferably substitute Ca in the CaTiO3 lattice, thus forming a solid solution (Ca1–xSrx)TiO3. The surplus of Ca ions forms single and ordered CaO-rich planar faults in the host (Ca1–xSrx)TiO3 phase. Whereas the excess Ca segregates in a form of single planar faults at lower temperatures, it forms a stable polytypoidic phase at higher temperatures. For materials having up to 25 mol% of SrO additions, this phase has (Ca1–xSrx)4Ti3O10 composition, comprising a sequence of CaO faults followed by three (Ca1–xSrx)TiO3 perovskite layers. Analytical electron microscopy revealed that the composition of the single planar faults, formed at lower temperatures, is identical to that of polytypoids, which are stable at higher sintering temperatures.

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Rice, Stephen E. « Modern Microscopy on the Light Side : TEM in the Trenches ». Microscopy Today 1, n^o 4 (juin 1993) : 6–10. http://dx.doi.org/10.1017/s1551929500067390.

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Great strides have been made in the last decade in high resolution transmission electron microscopes (TEMs) which can also provide elemental information via energy dispersive X-ray analysis (EDX) or energy loss spectroscopy (EELS), and proponents of various TEM techniques make bold claims. Convergent beam elecjron diffraction and microdifff action shine as techniques for defect structure analysis and means for solving crystal structures. The spectroscopies can now be used to map chemical state information at a level which until recently might be encountered in science fiction. As a pure imaging device, electron holography holds great promise for providing Ehe ultimate (would you believe 0.1Å?) imaging resolution. Although conventional TEMs will never approach this, it appears that we are learning more and more about less and less, until we will soon know everything there is to know about nothing.

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Fernandez, L., M. Blanco-Rey, R. Castrillo-Bodero, M. Ilyn, K. Ali, E. Turco, M. Corso et al. « Influence of 4f filling on electronic and magnetic properties of rare earth-Au surface compounds ». Nanoscale 12, n^o 43 (2020) : 22258–67. http://dx.doi.org/10.1039/d0nr04964f.

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HoAu₂, YbAu₂ and GdAu₂ surface compounds are investigated by electron spectroscopies, microscopy and theory. Yb in YbAu₂ reveals a mixed valence character while Gd and Ho are trivalent. HoAu₂ is ferromagnetic with an out-of-plane easy axis and T_C = 22 K.

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Dinarelli, S., F. Mura, C. Mancini, G. La Penna, T. Rinaldi et M. Rossi. « Comparison of different correlative AFM-SEM workflows on calcite moonmilk ». IOP Conference Series : Materials Science and Engineering 1265, n^o 1 (1 novembre 2022) : 012011. http://dx.doi.org/10.1088/1757-899x/1265/1/012011.

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In recent years, high resolution microscopy techniques are evolving toward a fast combination of different microscopies and spectroscopies, generally labelled under the title of correlative microscopy, each capable to provide unique information and a more comprehensive characterization of the sample under analysis. Among them stands out the Correlative Probe to Electron Microscopy (CPEM), where Scanning Electron Microscopy and Scanning Probe Microscopy are combined. This kind of technique is relatively new, and its range of capabilities is still not fully explored. In this paper, a demonstration of different CPEM workflows to characterize the moonmilk, a particular type of nanostructured calcium carbonate, extracted from ancient tombs of the Etruscan Necropolis of Tarquinia, is provided. Besides, the advantages of an innovative AFM-in-SEM setup, even respect to the standard standalone AFM measurement, are presented, showing how the analysis of the moonmilk nano-fibers, a rather challenging sample to be analysed with probe microscopies, is simplified and with less risk of artefacts or contamination of the AFM probe.

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Granados-Martínez, Francisco G., José J. Contreras-Navarrete, Jael M. Ambriz-Torres, Carmen J. Gutiérrez-García, Diana L. García-Ruiz, Jaime A. Guzmán-Fuentes, Nelly Flores-Ramírez et al. « MWCNTs-polymer composites characterization through spectroscopies : FTIR and Raman ». MRS Advances 3, n^o 63 (2018) : 3757–62. http://dx.doi.org/10.1557/adv.2018.627.

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ABSTRACTComposites from carbon nanotubes and polymers have been synthesized and studied. The composites were obtained joining carbon nanotubes with polymethyl methacrylate, nylon-6 and polystyrene. The materials were observed through scanning electron microscopy to evaluate the carbon nanotubes dispersion in the polymeric matrices. FTIR and Raman spectroscopies were used to analyze the interactions among functionalized and non-functionalized multiwalled carbon nanotubes and polymers, demonstrating affinity and peculiar spectra behaviors for each composite with different carbon nanotubes loads.

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Taurino, Antonietta, et Elvio Carlino. « The Relevance of Building an Appropriate Environment around an Atomic Resolution Transmission Electron Microscope as Prerequisite for Reliable Quantitative Experiments : It Should Be Obvious, but It Is a Subtle Never-Ending Story ! » Materials 16, n^o 3 (28 janvier 2023) : 1123. http://dx.doi.org/10.3390/ma16031123.

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The realization of electron microscopy facilities all over the world has experienced a paramount increase in the last decades. This means huge investments of public and private money due to the high costs of equipment, but also for maintenance and running costs. The proper design of a transmission electron microscopy facility is mandatory to fully use the advanced performances of modern equipment, capable of atomic resolution imaging and spectroscopies, and it is a prerequisite to conceive new methodologies for future advances of the knowledge. Nonetheless, even today, in too many cases around the world, the realization of the environment hosting the equipment is not appropriate and negatively influences the scientific quality of the results during the life of the infrastructure, practically vanishing the investment made. In this study, the key issues related to the realization of an advanced electron microscopy infrastructure are analyzed based on personal experience of more than thirty years, and on the literature.

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Bonhomme, A., L. Pingret, P. Bonhomme, J. Michel, G. Balossier, M. Lhotel, M. Pluot et J. M. Pinon. « Subcellular calcium localization inToxoplasma gondii by electron microscopy and by X-ray and electron energy loss spectroscopies ». Microscopy Research and Technique 25, n^o 4 (1 juillet 1993) : 276–85. http://dx.doi.org/10.1002/jemt.1070250403.

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Pennycook, Stephen J., et Christian Colliex. « Spectroscopic imaging in electron microscopy ». MRS Bulletin 37, n^o 1 (janvier 2012) : 13–18. http://dx.doi.org/10.1557/mrs.2011.332.

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Pagliari, Francesca, Elisa Sogne, Davide Panella, Gerardo Perozziello, Carlo Liberale, Gobind Das, Alice Turdo et al. « Correlative Raman–Electron–Light (CREL) Microscopy Analysis of Lipid Droplets in Melanoma Cancer Stem Cells ». Biosensors 12, n^o 12 (1 décembre 2022) : 1102. http://dx.doi.org/10.3390/bios12121102.

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Among all neoplasms, melanoma is characterized by a very high percentage of cancer stem cells (CSCs). Several markers have been proposed for their identification, and lipid droplets (LDs) are among them. Different techniques are used for their characterization such as mass spectrometry, imaging techniques, and vibrational spectroscopies. Some emerging experimental approaches for the study of LDs are represented by correlative light–electron microscopy and by correlative Raman imaging–scanning electron microscopy (SEM). Based on these scientific approaches, we developed a novel methodology (CREL) by combining Raman micro-spectroscopy, confocal fluorescence microscopy, and SEM coupled with an energy-dispersive X-ray spectroscopy module. This procedure correlated cellular morphology, chemical properties, and spatial distribution from the same region of interest, and in this work, we presented the application of CREL for the analysis of LDs within patient-derived melanoma CSCs (MCSCs).

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Panzarasa, Guido, Giovanni Consolati, Marco Scavini, Mariangela Longhi et Fiorenza Quasso. « Convenient Preparation of Graphene Oxide from Expandable Graphite and Its Characterization by Positron Annihilation Lifetime Spectroscopy ». C 5, n^o 1 (11 janvier 2019) : 6. http://dx.doi.org/10.3390/c5010006.

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Graphene oxide (GO) is conveniently prepared from expandable graphite using a simplified Hummers’ method. The product is thoroughly characterized by usual techniques (UV-vis, Fourier-transform infrared (FTIR) and Raman spectroscopies, zeta potential, electron microscopy, X-ray diffraction, nitrogen adsorption) to confirm the success of synthesis. Positron annihilation lifetime spectroscopy (PALS) is then used to extract information on the microenvironment in between the layers of graphene oxide.

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Sahu, Sumit Ranjan, Mayanglambam Manolata Devi, Puspal Mukherjee, Pratik Sen et Krishanu Biswas. « Optical Property Characterization of Novel Graphene-X (X=Ag, Au and Cu) Nanoparticle Hybrids ». Journal of Nanomaterials 2013 (2013) : 1–9. http://dx.doi.org/10.1155/2013/232409.

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The present investigation reports new results on optical properties of graphene-metal nanocomposites. These composites were prepared by a solution-based chemical approach. Graphene has been prepared by thermal reduction of graphene oxide (GO) at 90°C by hydrazine hydrate in an ammoniacal medium. This ammoniacal solution acts as a solvent as well as a basic medium where agglomeration of graphene can be prevented. This graphene solution has further been used for functionalization with Ag, Au, and Cu nanoparticles (NPs). The samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, UV-Vis spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) to reveal the nature and type of interaction of metal nanoparticles with graphene. The results indicate distinct shift of graphene bands both in Raman and UV-Vis spectroscopies due to the presence of the metal nanoparticles. Raman spectroscopic analysis indicates blue shift of D and G bands in Raman spectra of graphene due to the presence of metal nanoparticles except for the G band of Cu-G, which undergoes red shift, reflecting the charge transfer interaction between graphene sheets and metal nanoparticles. UV-Vis spectroscopic analysis also indicates blue shift of graphene absorption peak in the hybrids. The plasmon peak position undergoes blue shift in Ag-G, whereas red shift is observed in Au-G and Cu-G.

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Abbasian, Mojtaba, Mojtaba Bakhshi, Mehdi Jaymand et Saber Ghasemi Karaj-Abad. « Nitroxide-mediated graft copolymerization of styrene from cellulose and its polymer/montmorillonite nanocomposite ». Journal of Elastomers & ; Plastics 51, n^o 5 (11 septembre 2018) : 473–89. http://dx.doi.org/10.1177/0095244318799498.

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Nitroxide-mediated polymerization was successfully employed for well-defined graft copolymerization of styrene (St) monomer from cellulose (Cell) backbone. For this purpose, Cell was acylated by 2-bromoisobutyryl bromide, and then 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) was immobilized onto Cell backbone using a nucleophilic substitution reaction to produce Cell-TEMPO macroinitiator. Afterward, St monomer was grafted onto Cell backbone through “grafting from” technique. The successful synthesis of Cell- g-polystyrene (PSt) copolymer was confirmed using Fourier transform infrared and proton nuclear magnetic resonance spectroscopies and scanning electron microscopy analysis. Finally, Cell- g-PSt/montmorillonite nanocomposite was fabricated through solution intercalation approach. The thermal properties and structural morphology of the resultant nanocomposite were investigated using thermogravimetric analysis and differential scanning calorimetry and transmission electron microscopy, respectively.

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Picca, Rosaria Anna, Anna Di Maria, Lenka Riháková, Annalisa Volpe, Maria Chiara Sportelli, Pietro Mario Lugarà, Antonio Ancona et Nicola Cioffi. « Laser Ablation Synthesis of Hybrid Copper/Silver Nanocolloids for Prospective Application as Nanoantimicrobial Agents for Food Packaging ». MRS Advances 1, n^o 56 (2016) : 3735–40. http://dx.doi.org/10.1557/adv.2016.336.

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ABSTRACTThis work is focused on the laser ablation synthesis of Cu/Ag nanocolloids in chitosan-based aqueous solution using a flow cell. A two-step process using femtosecond laser pulses was applied to consecutively ablate each metal. As-prepared nanomaterials were morphologically and spectroscopically characterized by Transmission Electron Microscopy, UV-Vis and X-ray Photoelectron spectroscopies. Application of Cu/Ag nanomaterials is envisaged as antibacterial materials for food packaging.

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Aleksandrova, G., B. Sukhov et B. Trofimov. « Formation of Water-Soluble Au-Nanobiocomposite with Dielectric Matrix ». International Journal of Nanoscience 18, n^o 03n04 (juin 2019) : 1940055. http://dx.doi.org/10.1142/s0219581x19400556.

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Water-soluble potentially biocompatible Au-containing nanocomposites based on the natural polysaccharide arabinogalactan were prepared. They were investigated by electronic and infrared spectroscopies, X-ray diffraction analysis and transmission electron microscopy. Stable zero-valence Au nanoparticles with an average particle size of 5–8[Formula: see text]nm are formed in the natural macromolecular matrix. The nanocomposites obtained are aggregatively stable and of interest for applications in medicine.

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Xu, Hao, Haijun Hu, Hongmei Wang, Yongjun Li et Yun Li. « Corrosion resistance of graphene/waterborne epoxy composite coatings in CO 2 -satarated NaCl solution ». Royal Society Open Science 7, n^o 5 (mai 2020) : 191943. http://dx.doi.org/10.1098/rsos.191943.

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This study investigated the corrosion resistance of graphene/waterborne epoxy composite coatings in CO 2 -satarated NaCl solution. The coatings were prepared by dispersing graphene in waterborne epoxy with the addition of carboxymethylcellulose sodium. The structure and composition of the coatings were characterized by scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared and Raman spectroscopies. The corrosion resistance of the composite coatings was investigated by potentiodynamic polarization measurements and electrochemical impedance spectroscopy. Composite coatings with more uniform surfaces and far fewer defects than blank waterborne epoxy coatings were obtained on 1020 steel. The 0.5 wt% graphene/waterborne epoxy composite coating exhibited a much lower corrosion rate and provided better water resistance properties and long-term protection than those of the blank epoxy coating in CO 2 -satarated NaCl solution.

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Balakrishnan, Sivakumar, Yurii K. Gun’ko, Gerhard F. Swiegers et Tatiana S. Perova. « Preparation and Characterisation of Metallorganic Precursors Derived Iron Oxides on Porous Silicon Layers ». Materials Science Forum 995 (juin 2020) : 63–68. http://dx.doi.org/10.4028/www.scientific.net/msf.995.63.

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Porous silicon has generated interest in scientific community after its photoluminescence discovery and thereafter, research was focused on to the chemical functionalization of silicon and subsequent anchoring of nanoparticles onto silicon surface. In the present work, the porous silicon has been effectively modified with magnetic nanoparticles which were prepared through metallorganic approach. The as-fabricated magnetic-porous silicon composites were characterised using FTIR and Raman spectroscopies, Scanning Electron Microscopy (SEM) as well as magnetic measurements.

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Shin, J., S. V. Kalinin, H. N. Lee, H. M. Christen, R. G. Moore, E. W. Plummer et A. P. Baddorf. « Surface stability of epitaxial SrRuO3 thin films in vacuum ». Journal of Materials Research 19, n^o 12 (1 décembre 2004) : 3447–50. http://dx.doi.org/10.1557/jmr.2004.0480.

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Surface stability of nearly defect-free epitaxial SrRuO3 thin films grown by pulsed laser deposition was studied using low-energy electron diffraction (LEED), scanning tunneling microscopy (STM), and electron spectroscopies. Even after exposure to atmosphere, surfaces exhibited distinct LEED patterns providing evidence of unusual chemical stability. Surface order disappeared after heating to 200 °C in vacuum. To investigate, SrRuO3 thin films were annealed up to 800 °C in high vacuum and examined for chemical state and topography. Formation of unit-cell deep pits and the Ru-rich particles begins at low temperatures. Hydrocarbon contamination on the surface contributes to this process.

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Nastulyavichus, A. A., S. N. Shelygina, L. F. Khaertdinova, A. A. Rudenko, D. A. Kirilenko, S. I. Kudryashov et A. A. Ionin. « Alloyed Au/Pd nanoparticles formed by laser ablation of thin films in liquid ». Laser Physics Letters 19, n^o 5 (8 avril 2022) : 055001. http://dx.doi.org/10.1088/1612-202x/ac624f.

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Abstract The formation of alloyed Au/Pd nanoparticles (NPs) from thin magnetron-deposited Au–Pd films by nanosecond laser ablation in water is investigated. The films weight loss dependence is studied by thickness, intensity and laser pulses per point. Prepared NPs are transferred onto the silica wafer and characterized by scanning and transmission electron microscopy as well as optical and energy-dispersive x-ray spectroscopies. NPs size distribution was obtained using the dynamic light scattering (DLS) method.

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Mahato, Neelima, Debananda Mohapatra, Moo Hwan Cho et Kwang Soon Ahn. « Semi-Polycrystalline–Polyaniline Empowered Electrochemical Capacitor ». Energies 15, n^o 6 (9 mars 2022) : 2001. http://dx.doi.org/10.3390/en15062001.

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We report on the formation of semi-polycrystalline polyaniline, a novel electroactive polymeric material synthesized by a modified surfactant-free chemical route and its enhanced electrochemical capacitive behavior. The material exhibits uniformly arranged spindle-shaped morphology in scanning electron microscopy and well-defined crystallographic lattices in the high-resolution transmission electron microscopy images. The X-ray diffraction spectrum reveals sharp peaks characteristic of a crystalline material. The characteristic chemical properties of polyaniline are recorded using Fourier transform infrared technology and laser Raman spectroscopies. The cyclic voltammetry curves exhibit features of surface-redox pseudocapacitance. The specific capacitance calculated for the material is 551 F g−1 at a scan rate of 10 mV s−1. The cycle stability and the coulombic efficiency recorded at a current density of 12 A g−1 exhibited good stability (90.3% and 99.5%, respectively) over 3000 cycles.

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Ciobanu, Carmen Steluta, Simona Liliana Iconaru, Florian Massuyeau, Liliana Violeta Constantin, Adrian Costescu et Daniela Predoi. « Synthesis, Structure, and Luminescent Properties of Europium-Doped Hydroxyapatite Nanocrystalline Powders ». Journal of Nanomaterials 2012 (2012) : 1–9. http://dx.doi.org/10.1155/2012/942801.

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The luminescent europium-doped hydroxyapatite (Eu:HAp, Ca10−xEux(PO4)6(OH)2) with0≤x≤0.2nanocrystalline powders was synthesized by coprecipitation. The structural, morphological, and textural properties were well characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The vibrational studies were performed by Fourier transform infrared, Raman, and photoluminescence spectroscopies. The X-ray diffraction analysis revealed that hydroxyapatite is the unique crystalline constituent of all the samples, indicating that Eu has been successfully inserted into the HAp lattice. Eu doping inhibits HAp crystallization, leading to a decrease of the average crystallite size from around 20 nm in the undoped sample to around 7 nm in the sample with the highest Eu concentration. Furthermore, the samples show the characteristic5D0→7F0transition observed at 578 nm related to Eu3+ions distributed on Ca2+sites of the apatitic structure.

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Delledonne, Chiara, Michela Albano, Tommaso Rovetta, Gianmarco Borghi, Mario Gentile, Anna Denia Marvelli, Piero Mezzabotta et al. « Rediscovering the Painting Technique of the 15th Century Panel Painting Depicting the Coronation of the Virgin by Michele di Matteo ». Heritage 7, n^o 1 (10 janvier 2024) : 324–37. http://dx.doi.org/10.3390/heritage7010016.

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The study concerned a diagnostic spectroscopic campaign carried out on the panel painting depicting the Coronation of the Virgin (first half of the 15th century) by the late-Gothic Italian painter Michele di Matteo. The main aims were the identification of the original painting materials and the characterization of the painter’s artistic technique. A combined approach based on non- and micro-invasive techniques was employed. Visible and ultraviolet-induced fluorescence photography was used to select the areas of interest for spectroscopic analyses; X-ray radiography assessed the state of conservation of the support, while X-ray fluorescence and external reflection Fourier transform infrared spectroscopies allowed the chemical identification of pigments, binders, and varnishes. Attenuated total reflection infrared spectroscopy, optical microscopy, and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy were used to visualize and characterize the materials in the pictorial layers. The results highlighted the presence of pigments, possibly applied with an egg binder, consistent with the period of the production of the painting, as well as modern pigments used during subsequent restorations: an imprimitura with lead white and a gypsum-based ground layer. Concerning the gilding, the guazzo technique was confirmed by identifying a red bolo substrate and gold leaf.

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Fan, Xiao Hui, Hong Juan Liu, Yan Ming Chen et Ting Sun. « Synthesis and Characterization of ZnS Nanoparticles by Using Polyvinylpyrrolidone as Stabilizer ». Advanced Materials Research 625 (décembre 2012) : 269–72. http://dx.doi.org/10.4028/www.scientific.net/amr.625.269.

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A simple synthesis method of PVP (polyvinylpyrrolidone) coated ZnS QDS has been developed. The optical properties and morphology for the as-synthesized ZnS nanoparticles were characterized by UV-Vis absorption spectroscopies and transmission electron microscopy (TEM). The results show that PVP could act as a better stabilizer for the formation of ZnS nanoparticles in N, N-dimethylformamide. The obtained ZnS nanoparticles have spherical morphology and a narrow size distribution. ZnS nanoparticles could give an apparent extionic absorption peaks and quantum confinement effects.

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Popescu, Laura Mădălina, Roxana Mioara Piticescu, Tinca Buruiană, Eugeniu Vasile, Roxana Truşcă et Viorel Bădiliţă. « A New Approach for the Synthesis of Nanostructured Polyurethane-Hydroxylapatite-based Hybrid Materials ». Zeitschrift für Naturforschung B 66, n^o 1 (1 janvier 2011) : 36–42. http://dx.doi.org/10.1515/znb-2011-0106.

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The structural properties of composites prepared by a hydrothermal method in high-pressure conditions and the role of pressure in the formation of hydroxylapatite-polyurethane (HAp-PU) materials with strong interactions between the two components were investigated. X-Ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), FT-IR and NMR analyses were used to characterize the composite powders from a structural, morphological and compositional point of view. Both FT-IR and NMR spectroscopies indicate interactions between hydroxylapatite and acid polyurethane

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Ermolaev, Georgy A., Marwa A. El-Sayed, Dmitry I. Yakubovsky, Kirill V. Voronin, Roman I. Romanov, Mikhail K. Tatmyshevskiy, Natalia V. Doroshina et al. « Optical Constants and Structural Properties of Epitaxial MoS2 Monolayers ». Nanomaterials 11, n^o 6 (27 mai 2021) : 1411. http://dx.doi.org/10.3390/nano11061411.

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Two-dimensional layers of transition-metal dichalcogenides (TMDs) have been widely studied owing to their exciting potential for applications in advanced electronic and optoelectronic devices. Typically, monolayers of TMDs are produced either by mechanical exfoliation or chemical vapor deposition (CVD). While the former produces high-quality flakes with a size limited to a few micrometers, the latter gives large-area layers but with a nonuniform surface resulting from multiple defects and randomly oriented domains. The use of epitaxy growth can produce continuous, crystalline and uniform films with fewer defects. Here, we present a comprehensive study of the optical and structural properties of a single layer of MoS2 synthesized by molecular beam epitaxy (MBE) on a sapphire substrate. For optical characterization, we performed spectroscopic ellipsometry over a broad spectral range (from 250 to 1700 nm) under variable incident angles. The structural quality was assessed by optical microscopy, atomic force microscopy, scanning electron microscopy, and Raman spectroscopy through which we were able to confirm that our sample contains a single-atomic layer of MoS2 with a low number of defects. Raman and photoluminescence spectroscopies revealed that MBE-synthesized MoS2 layers exhibit a two-times higher quantum yield of photoluminescence along with lower photobleaching compared to CVD-grown MoS2, thus making it an attractive candidate for photonic applications.

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Martis, Joel, Ze Zhang, Hao-Kun Li, Ann Marshall, Roy Kim et Arun Majumdar. « Design and Construction of an Optical TEM Specimen Holder ». Microscopy Today 29, n^o 5 (septembre 2021) : 40–44. http://dx.doi.org/10.1017/s1551929521001103.

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Abstract:Electron microscopy has enabled atomic resolution imaging of matter. However, unlike optical spectroscopic imaging, traditional electron microscopes provide limited spectroscopic information in terms of their energy resolution. Only recently, owing to advances in monochromated STEM-EELS, have transmission electron microscopes (TEMs) been able to attain a high energy resolution. We recently proposed combining spectrally selective photoexcitation with HRTEM to achieve sub-nanometer scale optical imaging, a technique we called photoabsorption microscopy using electron analysis (PAMELA). To realize PAMELA-TEM experimentally, we constructed a TEM holder with an optical feedthrough, capable of photoexciting materials with different wavelengths. In this article, we describe our process for designing and fabricating an optical TEM specimen holder, highlighting important aspects of the design.

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Spadaro, Salvatore, Martina Bonsignore, Enza Fazio, Francesco Cimino, Antonio Speciale, Domenico Trombetta, Francesco Barreca, Antonina Saija et Fortunato Neri. « Molybdenum oxide nanocolloids prepared by an external field-assisted laser ablation in water ». EPJ Web of Conferences 167 (2018) : 04009. http://dx.doi.org/10.1051/epjconf/201816704009.

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he synthesis of extremely stable molybdenum oxide nanocolloids by pulsed laser ablation was studied. This green technique ensures the formation of contaminant-free nanostructures and the absence of by-products. A focused picosecond pulsed laser beam was used to ablate a solid molybdenum target immersed in deionized water. Molybdenum oxide nearly spherical nanoparticles with dimensions within few nanometers (20-100 nm) are synthesized when the ablation processes were carried out, in water, at room temperature and 80°C. The application of an external electric field during the ablation process induces a nanostructures reorganization, as indicated by Scanning-Transmission Electron Microscopy images analysis. The ablation products were also characterized by some spectroscopic techniques: conventional UV-vis optical absorption, atomic absorption, dynamic light scattering, micro-Raman and X-ray photoelectron spectroscopies. Finally, NIH/3T3 mouse fibroblasts were used to evaluate cell viability by the sulforhodamine B assay

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Batson, Philip, David Muller, Lawrence Allard, Paul Voyles, Miofang Chi et Michael O'Keefe. « Pre-Meeting Congress on Opportunities, Artifacts and Interpretation of Aberration-Corrected Electron Microscopy Data ». Microscopy and Microanalysis 17, S1 (4 juillet 2011) : 20. http://dx.doi.org/10.1017/s1431927611000729.

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This one-day pre-meeting congress, organized by the MSA Aberration-Corrected Electron Microscopy (ACEM) FIG, will be a forum for the discussion of the latest advances and solutions to problems associated with application of aberration correction technology. There will be platform presentations by both invited and contributed speakers, with poster presentations during a working lunch. Invited speakers will introduce innovations and issues, while contributors will highlight practical experiences and solutions to problems encountered during the application of ACEM to on-going experimental studies. This workshop includes: image collection/interpretation, new spectroscopies or other signals, artifacts and practical experiences in applications of ACEM to difficult situations such as hard/soft materials and in-situ experiments. All platform presentations will be intentionally kept short (∼15–20 minutes) to allow the maximum amount of interaction and information flow among attendees. Please send one page abstracts, including figures, to batson@rutgers.edu with the subject line: M&M PMC Abstract.

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Yoshida, Hiroyuki, et Abduheber Mirzehmet. « (Invited) Surface/Interface Structures of Perovskite Films Studied By Electron Spectroscopies ». ECS Meeting Abstracts MA2022-01, n^o 13 (7 juillet 2022) : 922. http://dx.doi.org/10.1149/ma2022-0113922mtgabs.

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Interface of perovskite layer play a crucial role in the charge extraction and recombination process of perovskite solar cell. It is, therefore, of great importance to examine the geometrical and electronic structures of surface/interface of perovskite. Unfortunately, standard experimental techniques such as X-ray diffraction (XRD) and scanning tunneling microscopy (STM) are not suitable to examine practical perovskite films for solar cells. XRD observes the lattice periodicity and is not sensitive to the surface structure. Although STM can precisely observe the surface atoms, it cannot be applied to rough surface or thick films, e.g. solution-processed perovskite surface. We have demonstrated that a combination of electron spectroscopies is powerful and versatile tool to examine both geometrical and electronic structures of perovskite surfaces. Figure 1 shows principles of ultraviolet photoelectron spectroscopy (UPS) and metastable atom electron spectroscopy (MAES). In UPS, the valence electrons are excited by ultraviolet photons (typically with the energy of 21.22 eV) and kinetic energies of photoelectrons are analyzed to measure the valence electronic states as a difference between the photon and electron kinetic energies. The probing depth of UPS is limited by the mean free path of electrons which is usually several layers a few nanometers (several layers) in the energy range of UPS. In MAES, the excitation source is replaced with the metastable helium atom (with the energy of 19.82 eV). Although the process as electron spectroscopy is similar to that of UPS, MAES is extremely surface sensitive because the helium atom can only interact with the outermost atomic orbitals of the sample surface. By comparing the UPS and MAES spectra, we can obtain information about the surface structure as well as the electronic states. In this presentation, we will demonstrate the following two topics: 1. Surface termination of CH3NH3PbI3 [1] The properties of the interface of perovskite ABX3 should be strongly affected by the surface termination, i.e. whether the surface is terminated with AX or BX layer. We examined the surface termination of a CH3NH3PbI3 thin film prepared by the standard one-step solution process. The results show that surface of the perovskite film is terminated with the layer consisting of CH3NH3 and I. 2. Surface structure of quasi-2D perovskite films, PEA2m(CH3NH3)n-2mPbnI3n [2] A small amount of large organic cations incorporated in perovskite film (quasi-2D) passivates the surface and enhances the stability of the perovskite solar cell against moisture. We examined surface structure of PEA2m(CH3NH3)n-2mPbnI3n, and confirmed that the PEA segregates to the surface and that the phenyl group covers the outermost surface of the quasi-2D perovskite. From the concentration dependence, we also examined the plausible structure of the quasi-2D film. 1) A. Mirzehmet, T. Ohtsuka, S. A. Abd. Rahman, T. Yuyama, P. Krüger, H. Yoshida, Adv. Mater. 33, 2004981 (2021). 2) A. Mirzehmet, T. Ohtsuka, S. A. Abd. Rahman, T. Aihara, M. A. Kamarudin, S. R. Sahamir, S. Hayase, T. Yuyama, P. Krüger, H. Yoshida, Appl. Phys. Express 14, 031006 (2021).

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Xiong, Shanxin, Yong Zhang, Yuyun Wang, Bohua Wu, Jia Chu, Xiaoqin Wang, Runlan Zhang, Ming Gong, Zhen Li et Zhenming Chen. « Comparative study on the supercapacitive properties of PANI nanofibers, nanotubes, and nanospheres ». High Performance Polymers 32, n^o 5 (28 novembre 2019) : 600–608. http://dx.doi.org/10.1177/0954008319890644.

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In this study, polyaniline (PANI) nanostructures with different morphologies (nanofibers, nanotubes, and nanospheres) were obtained via interfacial polymerization, rapid mixing reaction, and hydrothermal method. The influences of the synthesis methods on the morphologies and supercapacitive properties of PANI nanostructures were investigated. The chemical structures of materials were characterized by Fourier-transform infrared and Raman spectroscopies. Scanning electron microscopy and transmission electron microscopy images were used to explore the morphologies of PANI nanostructures. N2 adsorption–desorption isotherm, cyclic voltammetry, charge–discharge test, and electrochemical impedance spectroscopy were used to characterize the pore distribution, electrochemical, and supercapacitive properties of PANI nanostructures. The results show that PANI nanotubes (PANI-T) exhibit the best electrochemical performances among three kinds of PANI nanostructures. The PANI-T exhibits high specific capacitances of 648 and 290 F g−1 at current densities of 0.5 and 10 A g−1, respectively, indicating its good supercapacitive property and rate capability. The enhanced electrochemical and supercapacitive performances can be attributed to its hollow nanotube structure.

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Ali, Roushown, S. F. Adil, Abdulrahman Al-warthan et M. Rafiq H. Siddiqui. « Identification of Active Phase for Selective Oxidation of Benzyl Alcohol with Molecular Oxygen Catalyzed by Copper-Manganese Oxide Nanoparticles ». Journal of Chemistry 2013 (2013) : 1–8. http://dx.doi.org/10.1155/2013/367261.

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Catalytic activity of copper-manganese mixed oxide nanoparticles (Cu/Mn = 1 : 2) prepared by coprecipitation method has been studied for selective oxidation of benzyl alcohol using molecular oxygen as an oxidizing agent. The copper-manganese (CuMn2) oxide catalyst exhibited high specific activity of 15.04 mmolg−1 h−1in oxidation of benzyl alcohol in toluene as solvent. A 100% conversion of the benzyl alcohol was achieved with >99% selectivity to benzaldehyde within a short reaction period at 102°C. It was found that the catalytic performance is dependent on calcination temperature, and best activity was obtained for the catalyst calcined at 300°C. The high catalytic performance of the catalyst can be attributed to the formation of active MnO2phase or absence of less active Mn2O3phase in the mixed CuMn2oxide. The catalyst has been characterized by powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer Emmett-Teller (BET) surface area measurement, and Fourier transform infrared (FT-IR) spectroscopies.

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Bogdanova, Alisa R., Dmitry V. Krasnikov, Eldar M. Khabushev, Javier A. Ramirez B., Yakov E. Matyushkin et Albert G. Nasibulin. « Role of Hydrogen in Ethylene-Based Synthesis of Single-Walled Carbon Nanotubes ». Nanomaterials 13, n^o 9 (28 avril 2023) : 1504. http://dx.doi.org/10.3390/nano13091504.

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We examined the effect of hydrogen on the growth of single-walled carbon nanotubes in the aerosol (a specific case of the floating catalyst) chemical vapor deposition process using ethylene as a carbon source and ferrocene as a precursor for a Fe-based catalyst. With a comprehensive set of physical methods (UV-vis-NIR and Raman spectroscopies, transmission electron microscopy, scanning electron microscopy, differential mobility analysis, and four-probe sheet resistance measurements), we showed hydrogen to inhibit ethylene pyrolysis extending the window of synthesis parameters. Moreover, the detailed study at different temperatures allowed us to distinguish three different regimes for the hydrogen effect: pyrolysis suppression at low concentrations (I) followed by surface cleaning/activation promotion (II), and surface blockage/nanotube etching (III) at the highest concentrations. We believe that such a detailed study will help to reveal the complex role of hydrogen and contribute toward the synthesis of single-walled carbon nanotubes with detailed characteristics.

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Koch, Christoph T., Wilfried Sigle, Rainer Höschen, Manfred Rühle, Erik Essers, Gerd Benner et Marko Matijevic. « SESAM : Exploring the Frontiers of Electron Microscopy ». Microscopy and Microanalysis 12, n^o 6 (11 octobre 2006) : 506–14. http://dx.doi.org/10.1017/s1431927606060624.

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We report on the sub-electron-volt-sub-angstrom microscope (SESAM), a high-resolution 200-kV FEG-TEM equipped with a monochromator and an in-column MANDOLINE filter. We report on recent results obtained with this instrument, demonstrating its performance (e.g., 87-meV energy resolution at 10-s exposure time, or a transmissivity of the energy filter of T1 eV = 11,000 nm2). New opportunities to do unique experiments that may advance the frontiers of microscopy in areas such as energy-filtered TEM, spectroscopy, energy-filtered electron diffraction and spectroscopic profiling are also discussed.

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