Deposition and Characterization of Y3Al5O12 (YAG) Films and Powders by Plasma Spray Synthesis

2000 ◽  
Vol 658 ◽  
Author(s):  
Sujatha D. Parukuttyammaa ◽  
Joshua Margolis ◽  
Haiming Liu ◽  
John B. Parise ◽  
Clare P. Grey ◽  
...  

ABSTRACTYAG powders and coatings were developed for the first time by a novel precursor plasma spraying technique using the radio frequency (RF) induction plasma technique. The XRD of the as -sprayed coating confirms the presence of YAG, H-YAP or O-YAP or a mixture of the above depending on the spray conditions. 27Al MAS NMR of the YAG coating corroborates the x-ray results. TEM studies on the coatings confirm that the coating consists of nano-structured particles. The successful spraying of these complex oxide coatings proves that chemistry of phase formation can be controlled in the plasma, thus opening up new avenues in material synthesis.

2018 ◽  
Vol 22 (09n10) ◽  
pp. 814-820
Author(s):  
Yingying Jia ◽  
Ling Xu ◽  
Bangshao Yin ◽  
Mingbo Zhou ◽  
Jianxin Song

Beginning with 5,10,15-triarylporphyrin-nickel complex, five meso-to-meso directly linked porphyrin-diazaporphyrin triads were successfully prepared for the first time through a series of reactions including formylation via Vilsmeier–Haack reaction, condensation with pyrrole, bromination with [Formula: see text]-Bromosuccinimide (NBS), oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), metal-templated cyclization of dibromodipyrrin-metal complexes with NaN[Formula: see text] and demetalization. All these triads were comprehensively characterized by [Formula: see text]H NMR, high-resolution mass spectrometry and UV-vis absorption. In addition, the structure of compound 6Ni was unambiguously determined by X-ray diffraction analysis, which showed that the two dihedral angles are both 86.65 (4)[Formula: see text] between each mean plane of porphyrin and that of central diazaporphyrin The UV-vis absorption spectra disclosed that the longest wavelengths of Soret bands and Q bands for these triads were observed at 429 and 642 nm, respectively. In contrast to diazaporphyrin-porphyrin dyads, diazaporphyrin dimers and diazaporphyrin monomers reported previously the molar extinction coefficients, particularly for triad 8Ni are much higher.


2018 ◽  
Vol 619 ◽  
pp. A16
Author(s):  
C. Vignali ◽  
P. Severgnini ◽  
E. Piconcelli ◽  
G. Lanzuisi ◽  
R. Gilli ◽  
...  

Context. The search for heavily obscured active galactic nuclei has been revitalized in the last five years by NuSTAR, which has provided a good census and spectral characterization of a population of such objects, mostly at low redshift, thanks to its enhanced sensitivity above 10 keV compared to previous X-ray facilities, and its hard X-ray imaging capabilities. Aims. We aim at demonstrating how NGC 2785, a local (z = 0.009) star-forming galaxy, is responsible, in virtue of its heavily obscured active nucleus, for significant contamination in the non-imaging BeppoSAX/PDS data of the relatively nearby (≈17′) quasar IRAS 09104+4109 (z = 0.44), which was originally mis-classified as Compton thick. Methods. We analyzed ≈71 ks NuSTAR data of NGC 2785 using the MYTorus model and provided a physical description of the X-ray properties of the source for the first time. Results. We found that NGC 2785 hosts a heavily obscured (NH ≈ 3 × 1024 cm−2) nucleus. The intrinsic X-ray luminosity of the source, once corrected for the measured obscuration (L2−10keV ≈ 1042 erg s−1), is consistent within a factor of a few with predictions based on the source mid-infrared flux using widely adopted correlations from the literature. Conclusions. Based on NuSTAR data and previous indications from the Neil Gehrels Swift Observatory (BAT instrument), we confirm that NGC 2785, because of its hard X-ray emission and spectral shape, was responsible for at least one third of the 20–100 keV emission observed using the PDS instrument onboard BeppoSAX, originally completely associated with IRAS 09104+4109. Such emission led to the erroneous classification of this source as a Compton-thick quasar, while it is now recognized as Compton thin.


2016 ◽  
Vol 683 ◽  
pp. 281-287 ◽  
Author(s):  
Ivan N. Lapin ◽  
Anastasiia V. Shabalina ◽  
Valery Svetlichnyi

Dispersions of cerium oxide nanoparticles in water, ethanol, and water-ethanol solution were synthesized for the first time using laser ablation of metallic target. The fundamental harmonic of nanosecond Nd:YAG laser was used. Nanocrystalline powders of cerium oxide were obtained from the dispersions. The average size of the crystallites was 17-19 nm. Phase composition of nanoparticles was confirmed by X-ray diffraction and Raman spectroscopy. It was found that carbon present on the surface of CeO2 particles. The materials obtained may be used as catalyst carriers for CO oxidation, and as active components of sunscreen cosmetic products.


2018 ◽  
Vol 83 (5) ◽  
pp. 593-609 ◽  
Author(s):  
Nevenka Elezovic ◽  
Piotr Zabinski ◽  
Mila Krstajic-Pajic ◽  
Tomasz Tokarski ◽  
Borka Jovic ◽  
...  

The AgPd alloys were electrodeposited onto Au and glassy carbon disc electrodes from the solution containing 0.001 mol dm-3 PdCl2 + 0.04 mol dm-3 AgCl + 0.1 mol dm-3 HCl + 12 mol dm-3 LiCl under the non-stationary diffusion (quiescent electrolyte) and convective diffusion (? = 1000 rpm) to the different amounts of charge and at different current densities. Electrodeposited alloy layers were characterized by the anodic linear sweep voltammetry (ALSV), scanning electron microscopy, energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The compositions of the AgPd alloys determined by the EDS were almost identical to the theoretically predicted ones, while the compositions obtained by XPS and ALSV analysis were similar to each other, but different from those obtained by EDS. Deviation from the theoretically predicted values (determined by the ratio jL(Pd)/j(Ag)) was more pronounced at lower current densities and lower charges of AgPd alloys electrodeposition, due to the lower current efficiencies for alloys electrodeposition. The ALSV analysis indicated the presence of Ag and Pd, expressed by two ALSV peaks, and in some cases the presence of the additional peak, which was found to correspond to the dissolution of large AgPd crystals, formed at thicker electrodeposits (higher electrodeposition charge), indicating, for the first time, that besides the phase structure, the morphology of alloy electrodeposit could also influence the shape of the ALSV response. In addition to Ag and Pd, the XPS analysis confirmed the presence of AgCl at the surface of samples electrodeposited to low thicknesses (amounts of charge).


Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1744
Author(s):  
Giuliana Taglieri ◽  
Valeria Daniele ◽  
Ludovico Macera ◽  
Ralf Schweins ◽  
Sandro Zorzi ◽  
...  

Waterlogged wooden artifacts represent an important historical legacy of our past. They are very fragile, especially due to the severe phenomenon of acidification that may occur in the presence of acid precursors. To date, a satisfactory solution for the deacidification of ancient wood on a large scale has still not been found. In this paper, we propose, for the first time, eco-friendly curative and preventive treatments using nanoparticles (NPs) of earth alkaline hydroxides dispersed in water and produced on a large scale. We present the characterization of the NPs (by X-ray diffraction, atomic-force and electron microscopy, and small-angle neutron scattering), together with the study of the deacidification efficiency of our treatments. We demonstrate that all our treatments are very effective for both curative and preventive aims, able to assure an almost neutral or slightly alkaline pH of the treated woods. Furthermore, the use of water as a solvent paves the way for large-scale and eco-friendly applications which avoid substances that are harmful for the environment and for human health.


2003 ◽  
Vol 58 (7) ◽  
pp. 672-677 ◽  
Author(s):  
Thomas Roßmeier ◽  
Nikolaus Korber

The compounds (NH4)3AsS4· 5 NH3 (1) and (NH4)3SbS4· 8 NH3 (2) were prepared by the reaction of Na3AsS4 and Na3SbS4 with a proton-charged ion exchange material in liquid ammonia and characterized by low temperature single crystal X-ray structure analysis. The ammonium-ammoniates show H3N-H···N-hydrogen bonds between the ammonium ion and ammonia molecules ranging from 1.86 to 2.55 Å (DHA-angles: 145 - 173°) and H3N-H···S-bonds to the thioanions between 2.36 and 2.97 Å (DHA-angles: 130 - 176°). The former of the interactions are responsible for the formation of [(NH3)2H]+, [(NH3)3H]+ and [(NH3)4H]+-complexes, the last two of which were characterized by X-ray analysis for the first time.


Fibers ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 79 ◽  
Author(s):  
Salvatore Laurita ◽  
Giovanna Rizzo

In this paper, new mineralogical and petrographical data of asbestiform Magnesio-riebeckite from ophiolite cropping out in the Pollino Unesco Global Geopark (southern Italy) are presented. Magnesio-riebeckite schists with HP-LT index mineral assemblage recorded metamorphic events in blueschist facies in the Frido Unit. Previous toxicological studies showed that asbestiform Magnesio-riebeckite species exhibited high carcinogenicity in previous intraperitoneal injection experiments with rats. The results have been obtained using different analytical techniques such as X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), and electron probe micro analysis (EPMA). Results show that all the samples contain fibrous Magnesio-riebeckite and/or prismatic, acicular crystals in aggregates. The concentration of elements in Magnesio-riebeckite crystals is: Na2O (4.12–6.26 wt%), MgO (8.22–10.87 wt%), FeO (19.07–23.81 wt%), SiO2 (52.05–56.06 wt%), CaO (1.12–4.53 wt%), Al2O3 (1.34–1.93 wt%), and MnO (0.10–0.34 wt%). Magnesio-riebeckite crystals are documented in the Pollino Unesco Global Geopark for the first time. For this reason, the aim of this paper is the characterization of Magnesio-riebeckite to improve the knowledge of this mineral in the studied area, because the release of fibers into the environment is dangerous for human health.


1997 ◽  
Vol 488 ◽  
Author(s):  
Chin-Ti Chen ◽  
Sish-Yuan Liao ◽  
Kuan-Jiuh Lin ◽  
Long-Li Lai

AbstractThe synthesis and characterization of donor-acceptor substituted unsymmetrical bisdithiolene nickel complexes are described for the first time. X-ray single crystal data indicate that the complexes exist with two types of bonding structures, namely, the π-localized and π-delocalized structures. The relation between bonding structures and the molecular second-order nonlinear optical properties, i.e., solvatochromism, dipole moment, and molecular first hyperpolarizability is discussed.


2011 ◽  
Vol 45 (1) ◽  
pp. 85-92 ◽  
Author(s):  
Christina Krywka ◽  
Henrike Neubauer ◽  
Marius Priebe ◽  
Tim Salditt ◽  
Jozef Keckes ◽  
...  

The micro- and nanofocus X-ray scattering (MINAXS) beamline of PETRA III is equipped with two consecutively arranged endstations, the last of which is the nanofocus endstation. The first in-beam commissioning of the experimental equipment was successfully performed at the end of 2010, using two-dimensionally confining hard X-ray silicon waveguides with cross sections of 50 nm × 50 µm to 50 nm × 2 µm for nanobeam generation. A full characterization of the waveguide-generated beams was performed, giving values for the beam geometries, the transmission efficiencies of the waveguides and absolute fluxes. Along with these results a detailed description of the setup is presented in this paper. A first high-resolution nanodiffraction experiment on a nanocrystalline TiN hard coating was performed to verify the resolution of the nanodiffraction setup and to reveal the local gradients across the blasted TiN coating. In conclusion, the main concern is the availability of the nanobeam, how it was generated and the fact that a beam out of a two-dimensionally confining waveguide was used for diffraction experiments for the first time.


2014 ◽  
Vol 971-973 ◽  
pp. 123-126
Author(s):  
Yong Ping Luo ◽  
Zong Hu Xiao ◽  
Shun Jian Xu ◽  
Wei Zhong ◽  
Huan Wen Wu ◽  
...  

It was reported for the first time that “Turnjujube-like” CdSe nanofibers have been assembled onto TiO2surface by electrochemical method of cyclic voltammetry, using CdSO4•8H2O and SeO2as raw material, can be used as a sensitizer of quantum dot-sensitized solar cell. CdSe morphology, structure characterization and optical properties are characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and ultraviolt-visible spectroscopy (UV–Vis), respectively. The experimental results show that the prepared “Turnjujube–like” CdSe nanofibers are zinc blende CdSe with cubic crystal system, and it have excellent light absorption within the wavelength range of 300–800 nm. It has a potential for the construction of QD-sensitized solar energy cell.


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