bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of Manganese doped ferroxane nanoparticles
Authors: Cortalezzi Maria M. , Rose Jerome , Tsui Eliza , Barron Andrew R. , Bottero Jean-Yves , Wiesner Mark 
Published: April 2011

ABSTRACTFerroxane nanoparticles are precursors to iron oxide ceramic porous membranes. The ferroxane-derived ceramics have an average pore size of 24 nm and a surface area of 80 m2/g. Previous work has shown that these membranes have a molecular weight cut off of 180,000 dalton and their permeability is comparable to commercially available membranes. The ferroxane nanoparticles were reacted with manganese acetyl acetonate and then applied to the fabrication of mixed metal oxides. The nanoparticles were dried to form a ceramic chip. Upon sintering, asymmetric mixed metal oxide ceramic membranes were obtained. The materials were characterized by EXAFS, EDAX imaging and IDX mapping. EXAFS showed that the atomic environment of the iron and dopant material was different from those in the initial compounds, thus confirming that the reaction took place. The concentration of dopant metal was between 7% and 10%, with uniform concentration throughout the material.
The Hydrogen Programs in China
Authors: Wang Qidong , Lei Changpin Chen Yongquan , Chen Lixing , Wang Xinghua 
Published: April 2011

ABSTRACTAccording to the stages of development, the hydrogen program in China can be divided into four periods since 1978. The chief activities and accomplishments in each period on hydrogen production, hydrogen processing and use of hydrogen in the form of energy are introduced. The work of consciously transforming the present energy system based upon coal-firing power plants and petroleum powered internal combustion engine vehicles into a hydrogen economy system with primary energy mainly based on renewable energies and recycling of biomass and the use of both electricity and hydrogen as energy vectors is just on its start.
Hydrogen Storage Properties of Magnesium Based Nanostructured/Amorphous Composite Materials
Authors: Au Ming 
Published: April 2011

ABSTRACTIn this work, nanostructured composite materials Mg-Ni, Mg-Ni-La, Mg-Ni-Ce and Mg-LaNi5 have been synthesized using the mechanical alloying process. The new materials produced have been investigated by X-ray diffraction (XRD), TEM, SEM and EDS for their phase compositions, crystal structure, grain size, particle morphology and the distribution of the catalyst elements. Hydrogen storage capacities and the hydriding-dehydriding kinetics of the new materials have been measured at different temperatures using a Sieverts apparatus. The results show that amorphous/nanostructured composite material Mg50%-Ni50% absorbs 5.89wt% within five minutes and desorbs 4.46% hydrogen within 50 minutes at 250°C respectively. Adding 5% La into Mg-Ni composite materials reduces the starting temperature of hydrogen absorption and desorption from 200°C to 25°C which suggests the formation of unstable hydrides. The composite material Mg80%-LaNi5 20% absorbs 1.96% hydrogen and releases 1.75 wt% hydrogen at 25°C. It is observed that mechanical alloying accelerates the hydrogenation kinetics of the magnesium based materials at low temperature, but a high temperature must be provided to release the absorbed hydrogen from the hydrided magnesium based materials. It is believed the dehydriding temperature is largely controlled by the thermodynamic configuration of magnesium hydride. Doping Mg-Ni nano/amorphous composite materials with lanthanum reduces the hydriding and dehydriding temperature. Although the stability of MgH2 can not be easily reduced by ball milling alone, the results suggest the thermodynamic properties of Mg-Ni nano/amorphous composite materials can be alternated by additives such as La or other effective elements. Further investigation toward understanding the mechanism of additives will be rewarded.
Effect of Heat Treatment on Properties of Ti-Mn Based Laves Phase Hydrogen Storage Alloys
Authors: Lijun Jang , Hailing Tu , Yi Chen , zhuo Huang , Feng Zhan 
Published: April 2011

AbstractEffect of heat treatment on the properties and microstructure of non-stoichiometric Ti-Mn based hydrogen storage alloys were investigated. The results were presented that the hydrogen storage capacity was increased and the width of P-C-T Plateau extended, but the slope of plateau increased after heat treatment. Through SEM, EDS and XRD analysis, it was found that the crystal parameters and cell volume was increased, meanwhile the composition homogeneity effectively enhanced and the content of C15 phase decreased after heat treatment. The accretion of slope of plateau would be related to the ratio of valence electron/atom of the alloys.
Investigation of Ti-doped NaAlH4 by solid-state NMR
Authors: Herberg Julie L. , Maxwell Robert S. , Majzoub Eric H. 
Published: April 2011

ABSTRACTIn recent years, the development of Ti-doped NaAlH4 as a hydrogen storage material has gained attention because of its large weight percentage of hydrogen (∼5 %) compared to traditional interstitial hydrides. The addition of transition-metal dopants, in the form of Ti-halides, such as TiCl3, dramatically improves the kinetics of the absorption and desorption of hydrogen from NaAlH4. However, the role that Ti plays in enhancing the absorption and desorption of H2 is still unknown. In the present study, 27Al, 23Na, and 1H MAS (Magic Angle Spinning) NMR (Nuclear Magnetic Resonance) has been performed to understand the titanium speciation in Ti-doped NaAlH4. All experiments were performed on a sample of crushed single crystals exposed to Ti during growth, a sample of solvent-mixed 4TiCl3 + 112NaAlH4, a reacted sample of solvent-mixed TiCl3 + 3NaAlH4 with THF, and a reacted sample of ball-milled TiCl3 + 3NaAlH4. The 27Al MAS NMR has shown differences in compound formation between solvent-mixed TiCl3 + 3NaAlH4 with THF and the ball-milled TiCl3 + 3NaAlH4. 27Al MAS NMR of the ball-milled mixture of fully-reacted TiCl3 + 3NaAlH4 showed spectral signatures of TiAl3 while, the solvent-mixed 4TiCl3 + 112NaAlH4, which is totally reacted, does not show the presence of TiAl3, but suggests the existence of Al2O3.
Ion Irradiation Effects in Solid Oxide Fuel Cell Electrolytes
Authors: Cheng Jeremy , Pornprasertsuk Rojana , Saito Yuji , Prinz Fritz B. 
Published: April 2011

ABSTRACTSingle crystal Ytrria-stabilized Zirconia was irradiated with Xe2+ and Xe3+ ions at 320 and 450 keV over a range of doses from 1013 to 1016 ions/cm2. Damage appears as a 150 nm surface layer with a dense dislocation network. The X-ray diffraction pattern shows an increasing lattice expansion with increasing dose that reaches a saturation point. Ion irradiation increases the surface conductance of the material; this effect is removed with certain post-treatments. Preliminary isotope depth profiling indicates enhanced ion diffusion in the damaged layer.
Synchrotron Diffraction Study of the Isothermal Oxidation of Uranium Dioxide at 250°C
Authors: Rousseau Gurvan , Desgranges Lionel , Nièpce Jean-Claude , Bérar Jean-François , Baldinozzi Gianguido 
Published: April 2011

ABSTRACTThe structural evolution of UO2 during its oxidation to U3O8 at 250°C in air was studied by in-situ synchrotron X-ray diffraction on the D2AM-CRG beamline at ESRF. The aim of this study is to determine the phases that are likely to appear during the long-term storage of spent nuclear fuel. Our results are in disagreement with the literature in which the existence of an intermediate cubic phase is not reported. Instead, an α-U3O7 tetragonal phase (c/a < 1) was mentioned but not definitively observed. These previous interpretations may have been the result of poor instrumental resolution.
“Burst-like” Characteristics of the δ/α′ Phase Transformation in Pu-Ga Alloys
Authors: Blobaum Kerri J.M. , Krenn Christopher R. , Haslam Jeffery J. , Wall Mark A. , Schwartz Adam J. 
Published: April 2011

ABSTRACTThe δ to α′ phase transformation in Pu-Ga alloys is intriguing for both scientific and technological reasons. On cooling, the ductile fcc δ-phase transforms martensitically to the brittle monoclinic α′-phase at approximately −120°C (depending on composition). This exothermic transformation involves a 20% volume contraction and a significant increase in resistivity. The reversion of α′ to δ involves a large temperature hysteresis and begins just above room temperature. In an attempt to better understand the underlying thermodynamics and kinetics responsible for these unusual features, we are examining the δ/α' transformations in a Pu-0.6 wt% Ga alloy using differential scanning calorimetry (DSC) and resistometry. Both techniques indicate that the martensite start temperature is −120°C and the austenite start temperature is 35°C. The heat of transformation is approximately 3 kJ/mole. During the α ′ → δ reversion, “spikes” and “steps” are observed in DSC and resistometry scans, respectively. These spikes and steps are periodic, and their periodicity with respect to temperature does not vary with heating rate. With an appropriate annealing cycle, including a “rest” at room temperature, these spikes and steps can be reproduced through many thermal cycles of a single sample.
Experimental verification of the need for either jj or intermediate coupling in the 5f states of plutonium
Authors: Moore K. T. , Wall M. A. , Schwartz A. J. , Chung B. W. , Tobin J. G. , Shuh D. K. , Schulze R. K. 
Published: April 2011

ABSTRACTHere, we demonstrate the power of electron energy-loss spectroscopy (EELS) in a transmission electron microscope (TEM) to investigate the electronic structure plutonium. Using EELS, TEM, and synchrotron-radiation-based X-ray absorption spectroscopy (XAS), we provide the first experimental evidence that Russell-Saunders (LS) coupling fails for the 5f states of Pu. These results support the assumption that only the use of jj or intermediate coupling is appropriate for the 5f states of Pu. EELS experiments were performed in a TEM and are coupled with image and diffraction data, therefore, the measurements are completely phase specific. It is shown that EELS in a TEM may be used to circumvent the difficulty of producing single-phase or single-crystal samples due to its high spatial resolution.
Soft X-ray Synchrotron Radiation Investigations of Actinide Materials Systems Utilizing X-ray Emission Spectroscopy and Resonant Inelastic X-ray Scattering
Authors: Shuh D. K. , Butorin S. M. , Guo J.-H. , Nordgren J. 
Published: April 2011

ABSTRACTSynchrotron radiation (SR) methods have been utilized with increasing frequency over the past several years to study topics in actinide science, ranging from those of a fundamental nature to those that address a specifically-targeted technical need. In particular, the emergence of microspectroscopic and fluorescence-based techniques have permitted investigations of actinide materials at sources of soft x-ray SR. Spectroscopic techniques with fluorescence-based detection are useful for actinide investigations since they are sensitive to small amounts of material and the information sampling depth may be varied. These characteristics also serve to simplify both sample preparation and safety considerations. Examples of investigations using these fluorescence techniques will be described along with their results, as well as the prospects for future investigations utilizing these methodologies.
Actinide Materials Research Supported by the Office of Basic Energy Sciences, U.S. Department of Energy
Authors: Morss Lester R. 
Published: April 2011

ABSTRACTThe fundamental research topic in actinide chemistry and materials sciences is the role that the 5f electrons play in bond formation, which provides the central focus for DOE BES-supported actinide science. Structural systematics of the actinide metals, oxides, and other compounds as a function of atomic number are well established. Magnetic measurements have shown that the light actinide metals have delocalized 5f orbitals (i.e., the 5f electrons form bands), whereas the f electrons become localized at americium. Thus, the magnetic behavior of the first part of the actinide series resembles that of the d transition metals whereas the heavier actinides exhibit behavior similar to the rare earth metals. Spectroscopic results have established electronic energy levels, crystal field splitting, and near-neighbor coordination. The 5f orbitals participate in the band structure of materials that contain the light actinide metals and some of their intermetallic compounds, and perhaps in molecular compounds. Molecular-level information on the geometry and bonding in solids, at surfaces, and in clusters can now be obtained at BES-supported facilities.
Am Doping in Copper-Oxide Superconducting Systems
Authors: Skanthakumar S. , Soderholm L. 
Published: April 2011

ABSTRACTThe effect of Am doping on the physical properties of three superconducting systems (RBa2Cu3O7, Pb2Sr2R1−xCaxCu3O8 and R2−xMxCuO4) have been studied using x-ray diffraction, x-ray absorption spectroscopy (XAS) and magnetic susceptibility experiments. Am is incorporated into all three systems as the tetravalent ion and superconductivity is not observed in any of the resultant compounds. The absence of superconductivity in Pb2Sr2Am0.5Ca0.5Cu3O8 is attributed to the transfer of charge from Am to the Cu-O planes. Systems that cannot incorporate a tetravalent ion, notably AmBa2Cu3O7 and Am2CuO4, do not form. Although Pr1.85Am0.15CuO4 forms with similar structure to Pr1.85Ce0.15CuO4, and Am like Ce is tetravalent, it is not superconducting. We argue that the absence of superconductivity in the Am doped Pr compound it is due to the hybridization of radially-extended f orbitals on the magnetic Am4+ ion with the Cu-O band states.
Photoelectron and X-ray Absorption Spectroscopy of Pu
Authors: Tobin J. G. , Chung B. , Schulze R. K. , Farr J. D. , Shuh D. K. 
Published: April 2011

ABSTRACTWe have performed Photoelectron Spectroscopy and X-Ray Absorption Spectroscopy upon highly radioactive samples of Plutonium at the Advanced Light Source in Berkeley, CA, USA. First results from alpha and delta Plutonium are reported as well as plans for future studies of actinide studies.
Electronic Structure of δ-Pu and PuCoGa5 from Photoemission and the Mixed Level Model
Authors: Joyce John J. , Wills John M. , Durakiewicz Tomasz , Guziewicz Elzbieta , Butterfield Martin T. , Arko Aloysius J. , Moore David P. , Sarrao John L. , Morales Luis A. , Eriksson Olle 
Published: April 2011

ABSTRACTThe electronic structure of δ-phase Pu metal and the Pu-based superconductor PuCoGa5 is explored using photoelectron spectroscopy and a novel theoretical scheme. Excellent agreement between calculation and experiment defines a path forward for understanding electronic structure aspects of Pu-based materials. The photoemission results show two separate regions of 5f electron spectral intensity, one at the Fermi energy and another centered 1.2 eV below the Fermi level. A comparison is made between the photoemission data and five computational schemes for δ-Pu. The results for δ-Pu and PuCoGa5 indicate 5f electron behavior on the threshold between localized and itinerant and a broader framework for understanding the fundamental electronic properties of the Pu 5f levels in general within two configurations, one localized and one itinerant.
Fermi liquid instabilities and superconductivity near quantum critical points in f-electron materials
Authors: Maple M. B. , Frederick N. A. , Jeffries J. R. , Ho P.-C. , Zapf V. S. 
Published: April 2011

ABSTRACTRecent experiments on single crystals of the compounds CeRh1−xCoxIn5 and PrOs4Sb12 are briefly reviewed. The temperature-composition (T-x) phase diagram of the heavy fermion pseudoternary system CeRh1−xCoxIn5, delineating the regions in which superconductivity, antiferromagnetism, and the coexistence of these two phenomena occur, has been established. Entropy vs x isotherms and residual resistivity vs x plots exhibit peaks near the critical concentration xcr ≈ 0.8 at which the Néel temperature appears to vanish (quantum critical point). The filled skutterudite compound PrOs4Sb12 exhibits unconventional superconductivity below Tc = 1.85 K that involves heavy fermion quasiparticles with an effective mass m* ≈ 50 me, where me is the mass of the free electron. The unconventional superconducting state appears to consist of several distinct superconducting phases and to break time reversal symmetry. A high field ordered phase occurs below ∼ 1 K and between ∼ 4.5 T and ∼ 15 T that appears to be associated with quadrupolar order. The heavy fermion state and superconductivity in PrOs4Sb12 may originate from the interaction between Pr3+ electric quadrupole moments and the charges of the conduction electrons. When Ru is substituted for Os in PrOs4Sb12, a minimum in Tc occurs at Pr(Os0.4Ru0.6)4Sb12, suggesting a competition between two types of superconductivity.
To Data Management and Beyond… for Photovoltaic Applications
Authors: Nelson Brent , Friedman Dan , Geisz John , Albin David , Benner John , Wang Qi 
Published: April 2011

ABSTRACTMaterial science tends to focus around a specific class of materials and devices. After an idea is created, an experiment is postulated, and then materials are grown and devices are fabricated. These materials and devices are characterized using a variety of techniques. Data from these laboratory steps are analyzed, conclusions are formulated, and knowledge is passed on through publications, presentations, and patents. Typically, data are tracked in the area of what is grown and what is measured, but corporate knowledge is often lost as to what motivated certain experiments or what was learned from those experiments. This can be due to many factors including corporate culture, lack of reporting of negative results, and lack of reporting of full data sets. Proper application of informatics must realize that data does not equal knowledge, but is the foundation for creating knowledge, which is far more useful than mere information. Combinatorial approaches for material growth, device fabrication, and subsequent characterization accelerate experimental throughput. Integrating these systems and their data at all levels ultimately will lead to key knowledge to discover new materials and invent new device structures. Well-designed informatics systems must fully relate all types of data and information, make full use of automation, enable data mining, and have an easy-to-use, fast, user interface.
Combinatorial Materials Development using Gradient Arrays. Sphere Covering Lattice Designs: Designs for Efficient use of Experimental Resources.
Authors: Cawse James N. 
Published: April 2011

ABSTRACTGradient arrays are now common tools in combinatorial chemistry for discovery of new leads to commercial materials. Although the cost per sample has dropped markedly with new high throughput methods, efficient use of experimental resources is still important. Examination of gradient arrays from an informational standpoint suggests that designs which use the concepts of sphere packing and covering will be more efficient than simple gradients. This is especially true in higher dimensional systems.
The Magnetic Structure of the Rare-Earth Intermetallic Compound La3Co29Si4B10
Authors: Zhang Heng , Hofmann M. , Kennedy S. J. , Campbell S. J. 
Published: April 2011

ABSTRACTA quaternary rare-earth intermetallic compound La3Co29Si4B10 has been synthesized and the crystal and magnetic structures investigated by neutron diffraction over the temperature range 7–300 K. Rietveld refinements of the neutron diffraction patterns demonstrate that La3Co29Si4B10 is tetragonal and isostructural with Nd3Ni29Si4B10. The magnetic scattering indicates that the moments of the Co sublattice are collinear and lie in the basal plane. The mean magnetic moment for the Co atoms is μ ∼ 0.5 μB, or 13.6μB/F.U., in agreement with magnetization measurements.
Using Non-linear Regression to Predict Bioresponse in a Combinatorial Library of Biodegradable Polymers
Authors: Smith Jack R. , Knight Doyle , Kohn Joachim , Rasheed Khaled , Weber Norbert , Abramson Sascha 
Published: April 2011

ABSTRACTWe have developed an empirical method to model bioresponse to the surfaces of biodegradable polymers in a combinatorial library using Artificial Neural Networks (ANN) in conjunction with molecular modeling and machine learning methodology. We validated the procedure by modeling human fibrinogen adsorption to 22 structurally distinct polymers. Subsequently, the method was used to model the more complicated phenomena of rat lung fibroblast and normal human fetal foreskin fibroblast proliferation in the presence of 24 and 44 different polymers, respectively. In each case, the root mean square (rms) percent error of the prediction was substantially less than the experimental variation, showing that the models can distinguish high and low performing polymers based on structure/property information. Using this method to screen candidate materials in terms of specific bioresponse prior to extensive experimental testing will greatly facilitate materials development for biomedical applications.
Heterogeneous Design. Structural diagrams of ternary systems
Authors: Lutsyk Vasily I. , Vorob'eva Vera P. 
Published: April 2011

ABSTRACTIt is proposed to supplement a phase diagram by a structural diagram, which represents the mass portions of phases, conglomerates or their elements upon the system concentration at fixed temperature. Methods of structural diagrams and concentration maps construction are considered. Concentration map is a projection of structural diagram. It marks a concentration triangle by the lines of constant mass portions of a phase or its elements.
High Throughput Measurements of Polymer Fluids for Formulations*
Authors: Beers Kathryn L. , Cabral João T. , Walls Howard J. , Amis Eric J. 
Published: April 2011

ABSTRACTRapid prototyping of microfluidic handling devices has gained popularity due to the ability to quickly test and modify new design features several times in one day. At the NIST Combinatorial Methods Center (NCMC), we have modified common microfluidic fabrication techniques to extend their use to organic fluids. Ultraviolet (UV) curable adhesives were used to create molded resins with increased solvent resistance. This has allowed the preparation of new types of combinatorial libraries and development of new measurement methods to complement the small sample sizes of these libraries. Most importantly, it can be used to tie together multiple stages of the formulation process, from the synthesis of polymers to the measurement of complex-fluid properties, in small and inexpensive platforms. Our first demonstrations of this technology are in the areas of emulsions and polymer blends. Measurement techniques include light and x-ray scattering and rheology. Milli-fluidic handling and measurements will increase the dimensions of parameter space that are available to accurate and systematic study of polymer solutions. These capabilities will also enable the generation of new information in the field of polymer formulations, which is presently dominated by empirical knowledge.