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Rare-earth-basedCa9RE(PO4)7 (RE = Nd, Gd, Dy) materials were synthesized by solid-state reaction at T = 1200 °C. The obtained tricalcium phosphate (TCP) materials are efficient light emitters due to the presence of RE3+ ions, although these ions are present at high concentrations. Moreover, in these host structures,&nbsp, these ions can be used as optical probes to study their local environments. Thus, photoluminescence (PL) emission spectra of the powder samples clearly indicated, for Dy3+ and Gd3+ ions, the presence of the RE3+ ion in low-symmetry sites with some local structural disorder, and the spectra show the presence of vibrational features (in the case of Gd3+). For the Nd3+ phase, emission bands are present around 900, 1050, and 1330 nm, originating from the 4F3/2 level. In general, these RE-TCP samples are interesting luminescent materials in the visible (Dy), UV (Gd), and NIR (Nd) regions, due to weak concentration quenching even for high concentrations of the emitting ion.

Nickel ferrite nanoparticles (NiFe2O4) synthesized by chemical co-precipitation method, are added to poly(vinylidene fluoride-co-hexafluoroproplyene) (PVDF-HFP) in specific concentrations (1, 2, and 3 wt%) and the composite nanofibers are fabricated by electrospinning. Structural investigation and morphology of the synthesized NiFe2O4 magnetic nanoparticles reveal its spinel nature. The crystalline behavior in addition to the ferroelectric properties of NiFe2O4 enhance the interfacial interaction with the polymer chains and creates better dipole alignment and phase transformations within the nanocomposite. The nanocomposite with 1 wt% NiFe2O4 shows the maximum dielectric constant of 118 at 1 Hz frequency, which is about 24 times higher than that of the neat polymer. At the typical concentration of 2 wt% NiFe2O4 in PVDF-HFP, the nanocomposite is capable to generate an output voltage of 4 V suggesting the possible use of those flexible and magnetic polymer nanocomposites in designing piezoelectric devices. The structural performance, dielectric properties and the energy harvesting performance of the PVDF-HFP/NiFe2O4 nanocomposites are demonstrated here based on the filler and polymer characteristics. This publication was made possible by NPRP grant 6-282-2-119 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. Scopus

Nowadays, there is a very high importance of composite research and variety of their applications in the modern world. In that sense, we researched hollow glass capillaries filled with dissolved Grubbs catalyst (GC) and dicyclopentadiene (DCPD) were incorporated into a fiber-reinforced epoxy with the aim of improving the flow of healing agents to the crack site. The morphological investigation of the crack site was performed using field emission scanning electron microscopy (FESEM), showing the difference between the samples depending on the used solvent. The software analysis of sample photographs has been performed by calculating the fractured/healed surface area of the samples, revealing that approximately 20% of the volume was affected by the impact. Fourier transform infrared spectroscopy (FTIR) revealed that poly (dicyclopentadiene) (PDCPD) formed at the healed interface. However, the FTIR investigation of catalyst stability in different solvents showed structural changes in GC and partial deactivation. The mechanical tests of the samples showed that a recovery of 60% after 24 h at room temperature could be achieved through the use of a solvent and very low concentration of GC. The performed research results are a good base to develop the model for predicting the processes and morphology, with the goal to design the final mechanical and in the future, thermal, properties in advance. This opens a new direction for future research in the field of composite healing. © 2020 Elsevier B.V.

Different classes of foldamers, which are synthetic oligomers that adopt well-defined conformations in solution, have been the subject of extensive studies devoted to the elucidation of the forces driving their secondary structures and their potential as bioactive molecules. Regardless of the backbone type (peptidic or abiotic), the most important features of foldamers are the high stability, easy predictability and tunability of their folding, as well as the possibility to endow them with enhanced biological functions, with respect to their natural counterparts, by the correct choice of monomers. Foldamers have also recently started playing a starring role in the self-assembly of higher-order structures. In this review, selected articles will be analyzed to show the striking number of self-assemblies obtained for foldamers with different backbones, which will be analyzed in order of increasing complexity. Starting from the simplest self-associations in solution (e.g., dimers of β-strands or helices, bundles, interpenetrating double and multiple helices), the formation of monolayers, vesicles, fibers, and eventually nanostructured solid tridimensional morphologies will be subsequently described. The experimental techniques used in the structural investigation, and in the determination of the driving forces and mechanisms underlying the self-assemblies, will be systematically reported. Where applicable, examples of biomimetic self-assembled foldamers and their interactions with biological components will be described.

H. Klym thanks to the Ministry of Education and Science of Ukraine for support and Dr. P. Demchenko for the assistance in XRD experiments., Crystallization transformation in the 80GeSe2-20Ga2Se3 chalcogenide glasses caused by annealing at 380 °C during different duration (25, 50, 80 and 100 hours) are studied using X-ray diffraction and atomic force microscopy methods. It is established that GeGa4Se phase of low- and high-temperature modification, Ga2Se3 phase (α- and γ-modification) and GeSe2 phases are crystallized during this process. It is shown that annealing duration over 50 h does not lead to further internal structural crystallization, while annealing for 80 h result in processes of surface crystallization., Ministry of Education and Science of Ukraine; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²

NASICON-type conductors based on LiGe2(PO4)3 are very promising lithium-conducting electrolytes for all-solid-state lithium-ion and lithium batteries. Al-doped LiGe2(PO4)3 solid electrolytes possessed higher conductivity (∼10-4 S/cm at room temperature) and stability versus metallic Li. In this paper, we present the structure study of Li1.5Al0.5Ge1.5(PO4)3 compound. Fast lithium-ion conductor Li1.5Al0.5Ge1.5(PO4)3 solid electrolyte have been obtained through glass crystallization at 820 °C during 8 h. Structural positions occupied by atoms have been examined by solid state nuclear magnetic resonance experiments. 6Li, 7Li, 27Al и 31P NMR measurements have been performed at room temperature.

The strengthening mechanism based on the formation of precipitates (Guinier-Preston (GP) zones) during decomposition of a metastable supersaturated solid solution is stable and effective below temperatures, which are typically overcome in the piston region facing the combustion chamber. Therefore, pistons experience a progressive loss of strength due to over-aging during service. This contribution reports of a structural investigation on a eutectic AlSi12CuNiMg alloy before and after fatigue testing at high temperatures (up to 350 °C). Metallography, color etching, SEM and TEM are used to elucidate the following aspects: 1) the structural features of the alloy (dendrites of α−phase, primary Si particle size and distribution, morphology and distribution of intermetallic phases); 2) the evolution of the strengthening mechanism (GP zones) with high temperature exposure.

The CuxNi1−xFe2O4 (x = 0.0, 0.2, 0.5, 0.8, 1.0) nanoferrite powder were synthesized through chemical co-precipitation method using only (FeCl3, 6H2O), (NiCl2, 6H2O), (CuCl2, 4H2O), NaOH and acid oleic as raw materials. The synthesized powder was characterized by X-ray diffraction (XRD); it was used to determine the structural properties. The transmission electron microscopy and the scanning electron microscopy were used to determine the morphology and particle size. The Fourier Transform Infra-Red (FT-IR) spectroscopy is used to deduce the structural investigation and confirmation of ferrite. Raman spectroscopy is used to verify that we have synthesized CuxNi1−xFe2O4 and determines their phonon modes. The thermo gravimetric analysis findings allow the thermal cycle determination of samples whereas differential thermal analysis findings allow the phase transition temperature identification. The optical study UV–Visible is used to calculate the band gap energies. The vibrating sample magnetometer was used to obtain the hysteresis parameters. In conclude, the XRD confirmed the single phase spinel structure. The lattice constant increased with the increased copper contents. The size of nanoparticles decreased with the increased copper contents. The magnetic property of the CuxNi1−xFe2O4 shows remarkable changes with change of Cu2+.The variation of copper substitution has a significant influence on the optical, grain size and magnetic properties. The mean crystalline size of the synthesized ferrite was in the range of 14–43 nm., The present work was supported by the Research Funds of Electrochemistry, Materials and Environment Research Unit UREME (UR17ES45), Faculty of Sciences Gabes University, Tunisia and Structures, Properties and Modeling of Solids (SPMS) Laboratory, Ecole Centrale Paris, France.

cited By 0; Conference of 11th IEEE Nanotechnology Materials and Devices Conference, NMDC 2016 ; Conference Date: 9 October 2016 Through 12 October 2016; Conference Code:125383; International audience; We demonstrated the high throughput production of ultra-thin SiNWs by the innovative Inductively Coupled Plasma (ICP) approach. Our investigations revealed that the vast majority (∼95%) of the ICP produced SiNWs grew according to the Oxide Assisted Growth mechanism, and the 5% through the Vapor-Liquid-Solid mechanism. These SiNWs present an intriguing internal nanostructure, that provides a new kind of nanocomposite, where quantum confinement effects are expected. Indeed, an intense photoluminescence emission in the near infra-red was observed. These results prove the ICP as a genuinely bulk process, which can be exploited for large scale production of thin SiNWs to be integrated into attractive large-area and flexible optoelectronic devices.

In this work, we present in depth structural investigations of nanocomposite ZnO: Ge thin films by utilizing a state of the art grazing incidence small angle x-ray spectroscopy (GISAXS) technique. The samples have been deposited by sequential r.f. and d.c. sputtering of ZnO and Ge thin film layers, respectively, on single crystal Si(100) substrates. Transformation of Ge layers into Ge nanoparticles (Ge-np) has been initiated by ex-situ rapid thermal annealing of asprepared thin film samples at 600 °C for 30, 60, and 90 s under forming gas atmosphere. A special attention has been paid on the effects of reactive and nonreactive growth of ZnO layers on the structural evolution of Ge-np. GISAXS analyses have been performed via cylindrical and spherical form factor calculations for different nanostructure types. Variations of the size, shape, and distributions of both ZnO and Ge nanostructures have been determined. It has been realized that GISAXS results are not only remarkably consistent with the electron microscopy observations but also provide additional information on the large scale size and shape distribution of the nanostructured components. © 2016 Author(s).

cited By 18; International audience; Third-generation TiO2 photocatalysts were prepared by implantation of C+ ions into 110nm thick TiO2 films. An accurate structural investigation was performed by Rutherford backscattering spectrometry, secondary ion mass spectrometry, X-ray diffraction, Raman-luminescence spectroscopy, and UV/VIS optical characterization. The C doping locally modified the TiO2 pure films, lowering the band-gap energy from 3.3eV to a value of 1.8eV, making the material sensitive to visible light. The synthesized materials are photocatalytically active in the degradation of organic compounds in water under both UV and visible light irradiation, without the help of any additional thermal treatment. These results increase the understanding of the C-doped titanium dioxide, helpful for future environmental applications.

International audience; This work focuses on the structural and electrical characterization of La-Ni-O coatings deposited by reactive magnetron sputtering using Plasma Emission Monitoring (PEM) which allows high deposition rate. The optimal regulation setpoint for lanthanumdeposition is determined and then the current dissipated on the nickel target is adjusted to obtain the convenient La/Ni ratio to achieve the K2NiF4 structure. After an appropriate annealing treatment, all coatings exhibit crystalline structures that depend on the La/Ni ratio. Some cracks appear on samples deposited on alumina substrates depending to the argon flow rate and influence their electrical behavior.

The preparation of highly porous piezoelectric materials offers a promising route to ultrasonic transducers with low acoustic impedancees suitable for ranging applications or gas flow measurements. Sol-gel derived lead titanate gel were dried at ambient pressure and under supercritical conditions. Electron microscopy, thermogravimetry and dilatometer measurements were made on samples of the prepared materials. Nitrogen adsorption experiments were performed to get information about the microstructure of gel samples that had been annealed for 1 h at temperatures between 110 and 550 deg C. A comprehensive model for the formation of lead titanate gels was established: primary particles are formed in the initial stage of hydrolysis and condense to yield secondary particles which are the building blocks for thr inorganic network of the wet gel. Solvent evaporation at ambient pressure leads to a complete breakdown of this hirarchy. the microstructural features of the alcogels are mainly conse rved throughout supercritical drying in carbon dioxide at 35 deg C, but shrinkage of secondary particles and their rearrangement result in a low mechanical stability of these aerogels. In contrast to the application of carbon dioxide, supercritical drying in isopropanol at 236 deg C promotes interparticle ripening and thus stabilization of the inorganic network. Under these conditions lead titanate aerogels with improved mechanical stability are obtained.

Transparent oxide semiconducting thin films based on mixed Ti-V oxides were prepared using a modified reactive magnetron sputtering method. Based on structural investigations performed with the help of x-ray diffraction and transmission electron microscopy analysis, two distinct regions in the prepared thin film have been observed: a nanocrystalline TiO2-V2O3-V2O5 mixed composition, and a thin layer consisting of amorphous phase and nanocystalline TiO2 phase deposited directly at the substrate. Optical measurements show excellent transmission in the visible spectral range of 73%, on average. Resistivity of the thin film was found at the order of 105 Ω cm at room temperature. The preparation of mixed Ti-V oxides provides a combination of high transparency and semiconducting properties.

Fe73.5Si13.5Cu1Nb3B9 and Fe77.2Si11.2Cu0.8Nb3.3B 7.5 nanocomposite materials consisting of nanocrystalline phase in an amorphous matrix were obtained by heat-treatment of their precursor amorphous ribbons. The influence of structural modifications induced during the heat-treatment on soft magnetic properties and magnetoimpedance (MI) effect have been studied. The structural investigations on both these ribbons revealed the presence of two phases, fine grained Fe3Si phase and a residual amorphous phase on heat-treatment. The maximum MI ratio obtained in the present study is 95 at f 4 MHz, for the optimized heat-treated Fe77.2Si 11.2Cu0.8Nb3.3B7.5 ribbon. This is ascribed to the increase in magnetic permeability and decrease in coercive force and intrinsic resistivity. Moreover, a maximum magnetic field sensitivity (?) of 8.3/Oe at f 2.5 MHz is obtained, for the optimized nanocrystalline Fe73.5Si13.5Cu1Nb3B9 ribbon. This suggests that tailoring of the nanocrystalline microstructures induced by optimum heat-treatment conditions can result in obtaining excellent combinations of the magnetic permeability and resistivity. Our results indicate that these Fe-based nanocrystalline materials can be ideally used for low magnetic field and high frequency sensor applications. � 2011 American Institute of Physics.

A new microfluidic sample-preparation system is presented for the structural investigation of proteins using small-angle X-ray scattering (SAXS) at synchrotrons. The system includes hardware and software features for precise fluidic control, sample mixing by diffusion, automated X-ray exposure control, UV absorbance measurements and automated data analysis. As little as 15 l of sample is required to perform a complete analysis cycle, including sample mixing, SAXS measurement, continuous UV absorbance measurements, and cleaning of the channels and X-ray cell with buffer. The complete analysis cycle can be performed in less than 3 min. Bovine serum albumin was used as a model protein to characterize the mixing efficiency and sample consumption of the system. The N2 fragment of an adaptor protein (p120-RasGAP) was used to demonstrate how the device can be used to survey the structural space of a protein by screening a wide set of conditions using high-throughput techniques. © 2011 International Union of Crystallography.