A5079666447- Chalcogenide Semiconductor Thin Films
- Nuclear Materials and Properties
- Quantum Dots Synthesis And Properties
- Rare-earth and actinide compounds
- Radioactive element chemistry and processing
- Copper-based nanomaterials and applications
- Advanced Semiconductor Detectors and Materials
- Nuclear materials and radiation effects
- Graphene research and applications
- ZnO doping and properties
- Advanced Photocatalysis Techniques
- Advanced Condensed Matter Physics
- Magnetic Properties of Alloys
- Advanced Chemical Physics Studies
- Metal and Thin Film Mechanics
- Supercapacitor Materials and Fabrication
- Complex Systems and Time Series Analysis
- Semiconductor Quantum Structures and Devices
- Semiconductor materials and interfaces
- Surface and Thin Film Phenomena
- High-pressure geophysics and materials
- Graphene and Nanomaterials Applications
- Intermetallics and Advanced Alloy Properties
- Chemical Synthesis and Characterization
- Magnetic and transport properties of perovskites and related materials
Universidad Marista de Mérida
2014-2024
University of Chicago
2023
Medical Research Network
2015
Los Alamos National Laboratory
1999-2005
New Jersey Institute of Technology
2005
Australian Nuclear Science and Technology Organisation
2003-2004
Pacific Northwest National Laboratory
2003-2004
Oak Ridge National Laboratory
2004
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2003
CEA Marcoule
2003
Pu L(3) X-ray near edge absorption spectra for Pu(0-VII) are reported more than 60 chalcogenides, chlorides, hydrates, hydroxides, nitrates, carbonates, oxy-hydroxides, and other compounds both as solids in solution, substituted zirconolite, perovskite, borosilicate glass. This large database extends the known correlations between energy shape of these from usual association XANES with valence site symmetry to higher order chemical effects. Because number different types, a novel unexpected...
This research was carried out to study the effect of turbidity on effectiveness ultraviolet light (UVC) for removing heterotrophic bacteria (HB) from two commercial recirculating aquaculture systems (RAS). We developed a simple and straightforward UV disinfection model based water predict cost-effectiveness disinfection. The UVC RAS1 (12.8 m3, 80 L min−1, indoor system) tested at 9.2, 9.9, 16.3, 17.2, 23.1 28.2 nephelometric units (NTU) after 24 h exposure. RAS2 (140 1140 outdoor 8.0, 11.0,...
X-ray pair distribution function (pdf) and U L3 extended x-ray absorption fine structure (EXAFS) neutron pdf measurements that give identical results for UO2 show U(VI)-oxo moieties with x rays mixed valence U4O9 U3O7, in contrast to the data indicate only U(V) sites no short U-O bonds as well other differences. In addition, although EXAFS spectra of are essentially at 30, 100, 200 K, those UO2+x compounds exhibit different nearest-neighbor distributions each temperature. Further tunneling...
Pu L(3) X-ray absorption fine structure spectra from 24 samples of PuO(2+x) (and two related Pu-substituted oxides), prepared by a variety methods, demonstrate that (1) although the sublattice remains ordered part distribution, nearest-neighbor O atoms even at x = 0 are found in multisite distribution with Pu-O distances consistent stable incorporation OH(-) possibly H(2)O and H(+)) into PuO(2) lattice; (2) excess oxidation is <1.9 A, multiply bound "oxo"-type ligands molecular complexes...
Using ab initio molecular dynamics simulations and nudged elastic band calculations we examine the finite temperature stability, transition pathways, migration mechanisms of large oxygen clusters in UO2+x. Here specifically consider recently proposed split quad-interstitial cuboctahedral clusters. It is shown that isolated may transform into more stable configurations are closely linked to quad-interstitial. The with respect single interstitials occupying empty octahedral holes UO2 lattice....
Se desarrolló una red de sensores inalámbrica con el protocolo ZigBee para monitorear un sistema experimental acuícola recirculación agua. La incluye temperatura, oxígeno disuelto, presión agua y aire, así como corriente eléctrica. alta densidad organismos requerida que estos sistemas sean económicamente viables nos presentan caso donde las redes pueden ser aplicadas preservar stock peces saludable reduciendo probabilidades fallas conlleven pérdidas en la producción. desarrollaron probaron...
Pu L(3) XAFS measurements show that the excess oxygen in single phase PuO(2+)(x)() occurs as oxo groups with Pu-O distances of 1.83-1.91 A. This distance and energy edge (via comparison a large number related compounds) are more consistent Pu(IV/V) than Pu(IV/VI) mixture. Analogous to Pu(IV) colloids, although Pu-Pu pair distribution remains site even when it shows substantial disorder, can display additional shells at specific up 3.4 A high fired materials no present, implying intrinsic...
A thorough structure determination has been performed on Cu2ZnSnS4 nanoparticles, a popular photovoltaic material, using neutron diffraction—to characterize the long-range average crystal structure—and X-ray absorption fine (XAFS) spectroscopy at Cu, Zn, and Sn K-edges to elucidate element-specific local structure. This is first combined multiscale approach nanoparticles of this material. The results indicate presence aperiodic disorder cation sites that diminished by annealing. involves...
The scientifically fascinating question of the spatial extent and bonding 5$f$ orbitals Pu its six different phases extends to \ensuremath{\delta}-retained alloys mechanism by which Ga a number other unrelated elements stabilize low density face-centered-cubic (fcc) structure. This issue phase stability is also important technologically because significance Science-Based Stockpile Stewardship. Answering these questions requires information on local order structure around effects Pu. We have...
Abstract Production of a ZnO–rGO composite, using novel one-pot method consisting in continuously flowing argon into GO aqueous suspension heated at 80 °C, the presence galvanized iron steel scrap is presented. FTIR shows complete disappearance functional groups and only C=C band remained, indicating extensive reduction. Raman spectra indicated sp 2 character increase after reaction E 2h mode ZnO. SEM showed submicron crystals identified by XRD as ZnO hexagonal phase, while TEM images...
The local atomic structure of multilayer films graphene oxide, cadmium sulfide, and sulfide–selenide was analyzed by X-ray absorption fine spectroscopy. were prepared sequential electrophoretic deposition successive ion layer adsorption reaction onto F-doped SnO2 substrates. obtained characterized scanning electron microscopy, energy dispersive spectroscopy, Raman UV–vis step-potential photocurrent response. From the transmittance data analysis, a direct band gap ranging from 2.13 to 2.3 eV...
X-ray-absorption fine structure measurements have been used to elucidate the local atomic of quaternary Zr, Y, Er, Ce/U cubic stabilized zirconia. These compounds display more complicated environments than those reported for simpler binary systems. While shortest cation-O distances are similar found in compounds, responding different sizes cations, we identified large distortions first-shell oxygen distribution involving long, 2.8--3.2 \AA{} that amorphous phase zirconium. The cation-cation...
The local atomic structure of \ensuremath{\alpha}-Pu was investigated using x-ray absorption fine (XAFS) spectroscopy. XAFS spectra were obtained for a zone-refined and the results compared to 32-year-old Ce-doped (0.34 at. %) samples. X-ray diffraction (XRD) patterns also measured materials. extent Bragg peaks showed that amorphization sample had not occurred despite prolonged exposure self-radiation. Analogous metastable \ensuremath{\delta}-Pu alloys, around Pu material shows possible...
δ Pu–Ga alloys and their response to self-irradiation are important scientifically because of the unique complexity Pu technologically importance in Science Based Stockpile Stewardship. The local order structure role Ga crucial understanding phase stability aging effects. X-ray diffraction that gives long-range average periodic component materials pair distribution functions analysis absorption fine give overall element specific have been used examine a variety new aged materials, including...
CdS(Se)/graphene oxide (GO) heterostructures have received significant attention due to their potential application in optoelectronic devices with tunable bandgap, efficient charge transfer, and enhanced photocatalytic photovoltaic activity. In this work, Density Functional Theory (DFT) calculations of the properties CdS(Se)/GO were performed. The results work function, band gap, optical absorption, edges CdS CdSe (001) (110) directions on graphene are presented. Various approaches simulate...
The local atomic structure of CdTe:In at an In concentration $6\mathrm{at}.%$ was investigated by x-ray absorption spectroscopy before and after photoexcitation 80 K. After photoexcitation, $K$ edge spectra change in both the near-edge fine (XAFS) regions, showing a structure. Cd Te structural parameters are consistent with CdTe did not photoexcitation. For In, only first shell contribution is present XAFS, indicating disordered environment beyond neighbors. relation these observations...
Abstract The ubiquitous, multi‐enzyme, nucleotide excision repair (NER) pathway is responsible for correcting a wide range of chemically and structurally distinct DNA lesions in the eukaryotic genome. Human XPA, 31 kDa, zinc‐associated protein, thought to play major NER role recognition damaged recruitment other proteins, including RPA, ERCC1, TFIIH, damage. Sequence analyses genetic evidence suggest that zinc associated with C4‐type motif, C10S‐X 2 ‐C108‐X 17 ‐C126‐X ‐C129, located minimal...
Mixed valence O-doped $\mathrm{U}{\mathrm{O}}_{2+x}$ and photoexcited $\mathrm{U}{\mathrm{O}}_{2}$ containing transitory ${\mathrm{U}}^{3+}$ ${\mathrm{U}}^{5+}$ host a coherent polaronic quantum phase (CPQP) that exhibits the characteristics of Fr\"ohlich-type, nonequilibrium, phonon-coupled Bose-Einstein condensate whose stability coherence are amplified by collective, anharmonic motions atoms charges. Complementary to available, detailed, real space information from scattering EXAFS, an...