bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth of Antimony Thin Films Using Perbenzylated Organometallic Precursors
Authors: Remington Michael P. , Kamepalli Smuruthi , Boudjouk Philip , Jarabek Bryan R. , Grier Dean G. , Winburn Ryan S. , Very Brian E. , McCarthy Gregory J. 
Published: April 2011

AbstractThe low temperature (ca. 300°C) deposition of antimony films by low-pressure chemical vapor deposition (LPCVD) on glass substrates from tribenzylantimony, Bn3Sb, is described. The facile elimination of the benzyl ligands results in preferentially oriented antimony films with low carbon content. The pyrolysis, decomposition mechanism and precursor design strategies are discussed. In addition, the deposition of bismuth from tribenzylbismuth, Bn3Bi, is presented. The potential for alloy growth using these precursors is discussed. Resulting films were characterized by XRD, SEM, and AFM.
Novel Organically Templated Mixed-Valent Titanium Phosphates with Open Framework Structures: Hydrothermal Synthesis and Characterization
Authors: Ekambaram S. , Sevov Slavi C. 
Published: April 2011

AbstractWe have hydrothermally synthesized the first reduced titanium phosphates with open-framework structures. The synthetic approach is quite unusual since elemental titanium is used. The full structural, thermal, magnetic, and spectroscopic characterization of a 1,3-diaminopropanetemplated compound, TiIIITiIV(PO4)(HPO4)2(H2O)2·(NH2CH2CH2CH2NH2)0.5, is presented. The frame of the compound is of the octahedral/tetrahedral type with octahedrally coordinated TiIII and TiIV atoms. The template of 1,3-diaminopropane occupies channels with dimensions that are comparable to those of many zeolites. Magnetic measurements are consistent with one d-electron per formula unit. TGA/DTA and IR data will be reported as well. This compound is most likely the first member of a larger class of reduced titanium phosphates. Some preliminary data suggests that similar reduced titanium phosphates with different templates and structures exist as well. All compounds are blue-purple due to Ti(III).
Processing and Performance of V205 Xerogel, Aerogel, and Aerogellike Materials as Lithium Intercalation Hosts
Authors: Manhart Leland H. , Xu Jun John , Coustier Fabrice , Passerini Stefano , Owens Boone B. , Smyrl William H. 
Published: April 2011

ABSTRACTVarious forms of vanadium pentoxide, including xerogel, aerogel, and aerogel-like forms, were prepared by sol-gel synthesis and processed by novel procedures following synthesis. It was demonstrated that the intrinsic thermodynamics of lithium intercalation of the ARG and ARG-like materials prepared by solvent exchange processes involving methyl formate (MF/ARG and MF/ARG-xslike) are identical, while they are drastically different from those of the parent XRG, which gives rise to significantly increased specific energies for the MF/ARG or MF/ARG-like as lithium intercalation hosts. All three forms are capable of reversibly intercalating up to four moles of Li+ ions per mole of V205 electrochemically and can be cathode candidates for rechargeable lithium batteries. Various processing methods for fabricating composite electrodes with the XRG led to specific capacity in the range of 300 to 350 mAh/g at C4Li/ 20 rate, and good cyclability.
Preparation of Niobium Oxides Cathodes by Chimie Douce and Some Electrochemical Properties
Authors: Hernandez A. , Sanchez E. , Torres-Gonzalez L. C. , Fuentes A. F. , Torres-Martinez L. M. 
Published: April 2011

ABSTRACTSol gel chemistry has been a useful technique to achieve hard-to-prepare metastable materials. Niobium oxide, for instance has a thermodynamic preference to crystallize on monocyclic lattice. Here, we were able to achieve synthesis of orthorhombic motif with a careful sol-gel preparation and tailored thermal treatment. Furthermore, formation of lithium inserted Nb205 phases were studied by electrochemical methods. When lithium is inserted, several single phases LixNb205 were observed in the range of 0 ≤ x ≤ 3.3 between 3.0 and 0.75 V. Even though the reaction is only reversible for x ≤ 1.8. Also, T-Nb205 polymorph showed improved intercalation characteristics.
New Iron Oxide Positive Active Material for Lithium Secondary Batteries
Authors: Amine K. , Yasuda H. , Yamachi M. 
Published: April 2011

ABSTRACTBeta-iron oxy-hydroxide, which exhibits a (2×2) tunnel-type structure similar to that of (α-MnO2, was found to intercalate reversibly lithium in the tunnels. This material exhibits three voltage plateaus at 2.3, 1.5 and 0.7 V and has an over all discharge capacity of 1100 mAh/g. When cycling in the 2–V region, the material exhibits high capacity of 275 mAh/g and very good cyclic reversibility. X-ray photoelectron spectroscopy (XPS) of the discharged material showed that iron is reduced to the divalent state, and the lithium incorporated in the tunnels is purely ionic. This result explains the good reversibility of this electrode material. When discharged to 0.5 V, however, the structure of the material collapsed, and metallic iron was detected in the X-ray diffraction pattern.
Host-Guest Systems in Microporous Carbons
Authors: Enoki Toshiaki , Takai Kazuyuki , Shibayama Yoshiyuki , Kobayashi Norikazu , Nakayama Atsuko , Sato Hirohiko , Yoshida Naohiko , Touhara Hidekazu 
Published: April 2011

ABSTRACTMicroporous activated carbon fibers (ACF) having huge specific surface areas are characterized as a three-dimensional network of nano-sized graphite domains. We investigate ACF-hosting host-guest systems aiming at novel phenomena produced by the host-guest interface interactions. An extraordinarily large amount of helium is condensed in the ACF micropores, suggesting the presence of ultra-micropores and the enhancement in the helium- nano-graphite interaction. Chemisorbed oxygen molecules are stabilized in the singlet states caused by the interaction with nano-graphite and it makes the micorpore volume swell. Iodine forms an intercalation system with nano-graphites through charge transfer process, in contrast with the behavior of bulk graphite that does not accept iodine as an acceptor-type intercalate. Fluorine reacting with nano-graphite generates dangling bond spins by breaking graphite π- bonds, where the fluorine-induced defect is found to have a widely extended electronic structure.
Performance Characteristics of Gel Polymer Electrolyte Separators in Rechargeable Lithium Ion Cells
Authors: Huang Weiwei , Akridge James R. 
Published: April 2011

ABSTRACTThe swelling behavior of poly(vinylidene fluoride-hexafluoropropylene), noted as P(VdF- HFP), was under various conditions. Increasing the HFP unit content in P(VdF-HFP) and temperature increased the swelling degree of the polymers considerably. The amount of the electrolyte solution absorbed by P(VdF-HFP) at room temperature showed the following trend: DMC>EC/DMC>DEC≈EC/DEC. The presence of LiPF6 in carbonate solvents did not affect on the swelling degree of PVdF and P(VdF-8%IIFP) in all solutions studied but lowered the swelling degree of P(VdF-15%HFP) in DMC, EC/DEC and EC/DMC/DEC solution at room temperature or prevented it from dissolution in the them at 55°C. A variable search experiment indicated that changing the pre-conditioning temperature from 21 to 55°C is more effective than other changes considered in the experiment for increasing high rate discharge capability. Some coins cells using the composite GPE separators had higher discharge capability than those using microporous polyethylene separators.
Rietveld Neutron Powder Profile Analysis and Electrical Conductivity of the Fast Silver-Ion Conductor (LaO)AgS
Authors: Wilmer Dirk , Wuensch Bernhardt J. , Jorgensen James D. 
Published: April 2011

ABSTRACTLanthanum silver oxysulfide, (LaO)AgS, exhibits a predominantly ionic conductivity of 10−3 to 10−1 S/cm between 300 K and 770 K. The tetragonal structure consists of alternating (LaO) and (AgS) sheets, their sequence being O-La-S-Ag-S-La-O. The structure suggests that ionic transport arises from migration of silver ions within the AgS layers analogous to sodium ion transport in Na-β-alumina.Neutron powder diffraction data measured at five temperatures between 300 K and 770 K are analysed using the Rietveld method to determine the distribution and thermal vibration parameters of the mobile silver ions. The structural investigation is accompanied by measurements of the total conductivity in the same temperature range in order to resolve severe discrepancies in the literature data.
Phase Transformations of Superionic PbSnF4 Above Ambient Temperature: X-Ray Diffraction Versus Temperature
Authors: DÉNÈS Georges , Milova Galina , Antonov Boris D. 
Published: April 2011

ABSTRACTPbSnF4 is the highest performance fluoride ion conductor. A fast amperometric response oxygen sensor based on PbSnF4 has been constructed and tested. A long life device with time independent response and reliable performance requires the materials used for its construction be stable over the life time of the device in the operating conditions. Since ionic conductivity is thermally activated, possible use at high temperature can be envisaged. Therefore, it is of prime importance to know in details the behavior of the material versus time in the expected temperature range of use and of storage. PbSnF4 can be prepared by many methods that we have investigated, and each method gives a material that is different from the others in one way or another (symmetry, strain, particle rendomization, particle dimensions, temperature range of stability). In addition, we have shown that several phase transitions take place versus temperature or when some other treatments are applied. Many of these transitions are very sluggish, and therefore give a false impression of stability, when the phases are actually metastable, and thus changes take place slowly over time. We have studied the stability of tetragonal α-PbSnF4 and o-PbSnF4 by use of X-ray diffraction, in the most probable conditions of use (ambient temperature to 200°C in air). Changes were found to take place, which should be taken into account in the design of devices and when establishing their optimum temperature of use and storage.
Oxygen Transport Kinetics in La0.5Sro0.5Fe0.8Ga0.2O3−δ Membranes Under Both Small and Large Oxygen Partial Pressure Gradients
Authors: Kim Sangtae , Jacobson Allan J. , Abeles Benjamin 
Published: April 2011

ABSTRACTOxygen permeation through a new perovskite La0.5Sr0.5Fe0.8Ga0.2O3−δ membrane has been measured both under small (air/He) and large (air/CO, CO2) oxygen partial pressure gradients. In both cases oxygen transport is close to surface limited. By modeling the pressure dependence of the oxygen flow rate under small pressure gradient an ambipolar diffusion coefficient 9.65 × 10−7cm2/s and a surface exchange coefficient 7.15 × 10−6 cm/s at 974 °C were determined. With air/CO, CO2 on the permeate side, the permeability increases linearly with the partial pressure of CO. The observed increase is greater than the maximum enhancement predicted by our model.
Mechanisms and Kinetics of Electrochemical Intercalation of Oxygen into Nd2NiO4+δ
Authors: Fritze H. , Tuller H. L. , Berthold J. , Schultrich B. 
Published: April 2011

ABSTRACTOverstoichiometric insertion of oxygen into thin films of Nd2NiO4+δwas performed electrochemically at room temperature (RT) in order to obtain an in-situ compositional analysis of the process. Thin Nd2NiO4+δlayers were deposited onto resonators of a Quartz Crystal Microbalance (QCM) by Pulsed Laser Deposition (PLD). Cyclic voltammograms showed oxidation and reduction peaks typical for these oxides. The change in oxygen stoichiometry was determined by in-situ QCM measurements during potential step experiments. The resulting maximum mass change was on the order of 50 ng and corresponded to a maximum excess oxygen content of δ = 0.12 in Nd2NiO4+δ. The time dependence of the mass change was described by a transport model which leads to oxygen diffusion coefficients in the range from 2.10−12 to 10−11 cm2/s depending on δ and the direction of the reaction.
The Applications of Neutron Scattering Methods to the Study of High-Temperature Protonic Conductors
Authors: Udovic T. J. , Yildirim T. , Karmonik C. , Huang Q. 
Published: April 2011

ABSTRACTPerovskite-based high-temperature protonic conductors have generated increased interest because of their potential use in such areas as solid-oxide fuel-cell technology. In this paper, we outline the utility of neutron scattering methods in conjunction with first-principles total-energy calculations for characterizing the proton dynamics in these materials.
Cerium Containing Chalcogenides with Chromatic Properties
Authors: Gauthier G. , Jobic S. , Macaujdiere P. , Brec R. 
Published: April 2011

ABSTRACTλ–Ce2S3, like many other cerium containing chalcogenides, presents a strong absorption in the visible spectra in relation with the CeIII-4fl → CeIII-5d1 electronic transition taking place at around 1.9 eV. This transition energy, that induces a red hue for the phase, can be increased by changing the nature of the Ce-S bonding, in particular through an enhancement of its ionicity. This can be made by inserting/substituting some alkali metal ions in the structure of λ-Ce2S3. The sodium-doped λ-Na3/8Ce15/2S3 phase for instance undergoes a CeIII-4f1 → Cemi-5d1 transition energy increase of 0.12 eV. This shift is sufficient to modify substantially the pigment properties of the material and it has been mainly related to the narrowing of the electronic bands. In CePS4, Ce2SiS5, Ce4Si3S12and Ce6Si4S17, strong covalent bondings enhance the ionic Ce-S bond through inductive effect, leading to a CeIII-4f1 → CeIII-5d1 electronic transition in the blue (Eg - 2.5 eV) hence the yellow hue of these materials. Within the Ce-Si-S family, small differences may be attributed to difference in the [CeSx] and [SiS4] polyhedra bonding. The Ce3(TS4 )2X family (X = Cl, Br, I, T = Si, Ge) does not show pigment properties because of the Ce-X bond inducing a more Ce-S ionic character (in particular when X = Br, I) and thus a higher gap that is found in the near ultraviolet. On the other hand, the phases present an important room temperature blue fluorescence.
Intercalate Aggregation and Nlo Properties of Intercalated Lamellar Chalcogeno Phosphate Lattices
Authors: Coradin T. , Clement R. , Amoual E. , Holt J. , Francis A. 
Published: April 2011

ABSTRACTIntercalation compounds of CdPS3 with 4-[4-(dimethylamino)-α-styryl]- 1-methylpyridine cation (DAMS+) exhibit high-efficiency optical second harmonic generation (SHG). This is unexpected since the native CdPS3 host crystallizes in a centrosymmetric lattice. It is believed that the SHG results from the aggregation of the intercalate within the interlamellar spaces of the host lattice. For efficient SHG the spatial organization must have a characteristic length scale on the order of the second harmonic wavelength, or about 1 micron. We have studied the temperature dependence of the fluorescence of CdPS3:DAMS intercalation compounds and have demonstrated the presence of DAMS aggregates.
The Surface Structure of Manganese Cation and MnTMPyP Intercalated Potassium Niobate
Authors: Lee D. H. , Kim Y. , Sato O. , Fujishima A. , Hashimoto K. 
Published: April 2011

AbstractK4Nb6O173H2O has a cation exchange ability in K+ ion existing in the interlayer and a property of photocatalyst host. As a preliminary step in the preparation of this catalyst, the cation exchange plays an important role. In this study, we prepared potassium niobate intercalated with Wn2+ and Mn(III)TMPyP7+ (Mn(III)5,10,15,20-tetra(4-pyridyl)-porphyrin) ions and observed the evidence of cation exchange in the interlayer by means of atomic force microscopy. AFM images showed that the Mn2+ ion and MnTMPy7+ cations regularly occupied the potassium sites. This indicates that the metallic oxide reduction center was formed in the interlayer by the cation exchanged species prior to redox treatment and not on the surface of the potassium niobate.
Preparing Titania Fibers and Their Photocatalytic Activity
Authors: Koike H. , Oki Y. , Takeuchi Y. 
Published: April 2011

AbstractContinuous titania fibers were prepared by a polytitanoxane precursor method. Polytitanoxane was synthesized through hydrolysis and polymerization reaction between partially chelated titanium isopropoxide and water without acid catalyst. Polytitanoxane, which was precipitated from an isopropanol solution by adding adequate amount of water to titanium isopropoxide, was then dried and dissolved in tetrahydrofuran. The concentrated viscous solution of polytitanoxane was considerably stable to further self-condensation and had good spinnability. The precursor fiber which was obtained by spinning the solution was calcined to form titania fibers.Two types of titania fibers were obtained under different calcination conditions from the same precursor fiber; Dense fiber with high tensile strength of higher than 1 GPa, and porous fiber with high surface area of more than 10 m2/g.Photocatalytic activity of those fibers was studied using the phenol mineralization reaction in water. The phenol degradation ability of high-surface-area titania fiber was almost the same as that of commercial titania powder for photocatalyst.
The Role of Hydrogen In The Structure of γ-Alumina
Authors: Sohlberg Karl , Pennycook Stephen J. , Pantelides Sokrates T. 
Published: April 2011

AbstractThe structure of a-alumina (α-A12O3) is well known to be hexagonal close packed. In contrast, the structures of the so-called transition aluminas (-γ-alumina, η-alumina,…) are the subject of controversy. We report theoretical calculations which show that -γ-alumina is actually a sequence of compounds with the general formula H3mAl2−mO3. (0 ≤ m ≤ ⅓). m = ⅛ is a unique form, HAl5O8, with a perfect spinel structure. For m > 8, there are interstitial H atoms whereas for m < ⅛. there are vacancies. This picture is supported m > ⅛ by calculations of material density and proton vibrational frequencies. The results are in excellent agreement with measured values. The present new systematic approach accounts for a wide range of seemingly contradictory data and leads to the conclusion that γ-alumina behaves as a “reactive sponge” by storing and releasing water in a novel reactive way.
Three Dimensional Ultra-Small Pt Clusters on Carbon As Studied by A Novel Stem Technique
Authors: Yang J. C. , Bradley S. , Gibson J. M. 
Published: April 2011

AbstractVery high angle (∼ 100mrad) annular dark-field (HAADF) images in a dedicated scanning transmission electron microscope (STEM) can be used to quantitatively measure the number of atoms in a cluster on a support material. We have developed a computer program which will automatically find the location of the particles and then integrate the intensity to find the number of atoms per cluster. We have examined ultra-small Pt clusters on a C substrate by this novel mass-spectroscopic technique. We discovered that the Pt clusters maintain their three-dimensional shape, and are probably spherical in shape.
Surface Mediation of NOxReduction/Oxidation in A Plasma
Authors: Balmer M.L. , Tonkyn R.G. , Yoon I. , Kolwaite A. , Barlow S.E. , Orlando T.M. , Hoard J. 
Published: April 2011

AbstractNOxreduction efficiency under simulated lean burn conditions is examined for a nonthermal plasma in combination with borosilicate glass, alumina, Cu-ZSM-5 and Na-ZSM-5. The non-thermal plasma alone or with a packed bed of borosilicate glass beads converts NO to NO2and partially oxidizes hydrocarbons. Alumina and Na-ZSM-5 reduce a maximum of 40% and 50% of NOxrespectively; however, the energy cost is high for Na-ZSM-5. Cu-ZSM-5 converts less than 20% with a very high energy consumption.
Catalytic Activity of Ni/(P)Ti-HMS Catalysts with Varying Phosphorous Concentration in The reaction Of dehydrogenation of Cyclohexane
Authors: Halachev T. , Viveros T. , Perez G. , Dimitrov L. 
Published: April 2011

AbstractNi/(P)Ti-HMS catalysts were prepared and characterized by several physicochernical techniques. The addition of phosphorous to the original mesoporous materials modified the acid-base surface properties. The activity in cyclohexane dehydrogenation is higher than on conventional catalysts.
Microporous Silicon Nitride-Based Solid Bases
Authors: Bradley J. S. , Vollmer O. , Rovai R. , Lefebvre F. 
Published: April 2011

AbstractHigh surface area, microporous, amorphous silicon imidonitride, characterized by infrared spectroscopy, MAS29Si NMR and surface area and porosity measurements has been prepared by the treatment of co-oligomers of methylsilazane and dimethyl silazanes with gaseous ammonia at temperatures up to 700°C. The material has a narrow pore-size distribution showing a maximum in the range associated with wide- pore zeolites (ca.0.72 nm mean). Variation of the organic content of the silazane is a means of controlling the surface area of the resulting solid. The Knoevenagel condensation reaction of benzaldehyde with a series of active methylene compounds has been used to probe the basicity and size-selectivity of these microporous solid base catalysts.
A Novel Versatile Process for the Production of Polymer Foams
Authors: Shastri V.P. , Martin I. , Langer R. 
Published: April 2011

AbstractPorous polymeric media are used in several applications such as solid supports for separations and catalysis, as well as biomedical applications such as vascular grafts and wound dressings. We have developed a novel versatile process to produce polymeric cellular solids. This process which is based on a phase extraction-co-polymer precipitation is applicable to a wide range of polymer systems including water soluble polymers. It is capable of yielding polymer foams of high porosity (> 90%) and excellent mechanical characteristics in a very short time (less than 2 hours) without limitations in foam thickness. Polymer foam with such characteristics have great utility in tissue engineering applications. We have successfully explored polymer foams of biocompatible polymers produced by the presented approach for bone and cartilage engineering using bone marrow stromal cells.
Non-Destructive Evaluation of Synthetic Tissue Scaffolds With NMR
Authors: Garrido L. 
Published: April 2011

AbstractProton magnetic resonance imaging (MRI) is applied to determine non–destructively the open porosity of biodegradable scaffolds of poly(3–hydroxybutyrate-–3–hydroxyvalerate) in vitro and tissue infiltration in vivo. Porous matrices with copolymers having 12% and 24% 3–hydroxyvalerate (HV) are prepared using a solvent casting technique. The results of open porosity P(%) measured by MRI (PMRI) show good agreement with those obtained by gravimetry analysis (PGA). Thus, for scaffolds with 12% HV, PMRI = 91.0 ±1.0 (mean ± s.d.) and PGA = 88.0 ± 0.75; and for those with 24% HV, PMRI = 89.4 ±1.3 and PGA = 88.8 ± 1.0. Also, the extent of tissue infiltration in these scaffolds determined by MRI in vivo was similar to that observed by histology. These results illustrate the potential of MRI methods for investigating the behavior of biodegradable scaffolds non-invasively in applications for tissue engineering.
Bioresorbable Microspheres as Injectable Cell Carrier: FRom Preparation to in Vitro Evaluation
Authors: Senuma Y. , Franceschin S. , Hilborn J. G. , Tissiéres P. , Frey P. 
Published: April 2011

AbstractA new approach to the vesico-ureteral reflux could be a local regeneration of the defective vesicoureteral junction by transplanting living cells to the target site. The aim of this work is to provide a long-term effective treatment by producing bioresorbable microspheres which can act as support matrix for those cells, with the goal of an in vivo transfer of the in vitro cultured cells with a minimal surgical procedure. After microsphere degradation, the cells should be integrated into the muscular structure of the junction. Most innovative is that these are cultured muscle and urothelial cells from the bladder of the same patient.