bluuebunny/crossref_metadata_2025_split huggingface dataset:
Similarities between the Coordination of Actinide Ions in Solution and the Structures of their Related Crystalline Phases
Authors: Soderholm L. , Skanthakumar S. , Burns Peter C , Forbes Tori 
Published: April 2011

AbstractHigh-energy x-ray scattering (HEXS) is used to probe correlations about selected actinide ions in solution. The experiments were designed to favor homoleptic water coordination in order to compare the preferred structural environment of UO22+, NpO2+, and Cm3+ with similar ligands. In addition to comparisons between the three actinide ions in solution, the results from the HEXS studies are also compared with known solid state structures. Marked similarities are found between near- and next-near neighbor coordination in solution and in the solid state.
Complexation of Actinides with Amide Derivatives of Oxydiacetic Acid
Authors: Rao Linfeng , Tian Guoxin 
Published: April 2011

AbstractComplexation of Np(V), U(VI) and Nd(III) with dimethyl-3-oxa-glutaramic acid (DMOGA) and tetramethyl-3-oxa-glutaramide (TMOGA) was studied in comparison with the complexation with oxydiacetic acid (ODA). Stability constants and enthalpy of complexation were determined by potentiometry, spectrophotometry and calorimetry. Thermodynamic parameters, in conjunction with structural information of solid compounds, indicate that DMOGA and TMOGA form tridentate complexes with the ether-oxygen participating in bonding with actinide/lanthanide ions. The trends in the stability constants, enthalpy and entropy of complexation are discussed in terms of the difference in the hydration of the amide groups and carboxylate groups and the difference in the charge density of the metal ions.
Nanostructures in Uranium Oxocompounds
Authors: Krivovichev Sergey V. , Tananaev Ivan G. , Myasoedov Boris F 
Published: April 2011

AbstractExamples of uranium-oxide-based nanostructures are considered, including 2D organic-inorganic nanocomposites and nanotubules. In nanocomposites, interfacial interactions between organic and inorganic substructures can be studied by charge-density matching principle. Application of this principle to uranyl compounds requires special attention since surface area of uranyl-based 2D units is higher than that of other inorganic oxysalts units (i.e. metal phosphates). The charge-density matching principle is, however, observed either through tail interdigitation (for long-chain monoamines) or incorporation of acid-water interlayers into organic substructure (for long-chain diamines). In some compounds, protonated amine molecules form cylindrical micelles that involves self-assembly governed by competing hydrophobic/hydrophillic interactions. The flexible inorganic complexes present in the reaction mixture could then form around cylindrical micelles to produce highly undulated 2D sheets or nanotubules.
Presence and Persistence of Uranyl Peroxide Nanoclusters in Contact with Geological Media
Authors: Kubatko Karrie-Ann , Gunderson Katie M. , Antonio Mark , Burns Peter C. , Soderholm L. 
Published: April 2011

AbstractRecently uranyl peroxide nanoclusters containing 24, 28, and 32 uranyl polyhedra were chemically and structurally characterized under alkaline conditions. Such nanoclusters could conceivable form from oxidative alteration of nuclear waste in a geological repository by incorporating peroxide formed by alpha-radiolysis of water or in tanks where high-level waste is stored. The stability and persistence of uranyl peroxides in the vadose zone will be impacted by their interaction with geological media. Here we report batch experiments of solutions containing monodisperse nanoclusters in contact with crushed welded tuff. Within the first 72 hours, U concentrations in solution remained unchanged; however concentrations of Si, Al, Ca, Mg, Na, and Fe increased due to the dissolution of calcium-bearing aluminum silicate minerals in the welded tuff. Despite the presence of excess Li+ in solution, within two weeks crystals precipitated in which Ca2+ replaced Li+ in the nanocluster cage.
Combinatorial Optimization of Low Electrical Resistivity Pd-based Thin Film Metallic Glass
Authors: Yamauchi Ryusuke , Hata Seiichi , Sakurai Junpei , Shimokohbe Akira 
Published: April 2011

AbstractIn order to optimize low electrical resistivity compositions of Pd-based thin film metallic glass (TFMG), Combinatorial arc plasma deposition (CAPD) was employed. A Pd-based continuous compositionally-graded thin film was deposited using CAPD in the experiments. To deposit the composition-grade of the Pd-rich thin film, the number of shots and the plasma strength were controlled. The deposited thin film was separated into 1,089 samples for measurements. The thickness, composition, phase and relative resistivity of these samples were measured respectively. And three amorphous CAPD samples exhibiting low relative resistivity were selected. To determine whether these were TFMG compositions, their compositions were reproduced on sputter-deposited samples and their Tg and Tx were measured. It was found that the sample of Pd81Cu5Si14 at.% showed the lowest absolute resistivity (60 μΩ·cm) and the largest temperature range of supercooled liquid region (SCLR) i.e., 60 K among all samples. The resistivity was 19% lower than conventional Pd-based TFMG and SCLR was two and half times as large. The tensile strength was higher than the conventional TFMG and the Young's modulus was lower than the conventional one.
Making Combinatorial Libraries of Titanium Based Alloys by Direct Metal Deposition Technique
Authors: Pimenova Natalia , Starr Thomas L. 
Published: April 2011

Abstractα/β type titanium alloys, such as Ti-6Al-4V and Ti-6Al-7Nb, have been used for orthopedic implant materials because of their combination of biocompatibility, corrosion resistance and mechanical properties. However, toxicity of alloying elements is a concern.In this project, it is proposed to design the new type of titanium alloys composed of non-toxic elements, such as Ti, Al, and Fe with lower modulus of elasticity and greater corrosion resistance. To find the optimal ratio of components in the Ti-Al-Fe system is important. The composition of the alloy determines its properties. Using combinatorial approach the optimal ratio can be found relatively easily.Direct metal deposition (DMD) is a novel precise manufacturing process for fabricating metal parts directly from Computer Aided Design (CAD) solid models. The DMD process allows making several layers of different composition on one substrate. One sample includes several Ti-xAl-yFe alloys at once. This combinatorial library dramatically reduces the time and cost of the investigation.The structure, mechanical and electrochemical properties of each new composition was studied using scanning electron microscopy (SEM) with energy-dispersive X-ray fluorescence analyzer (EDAX ZAF®), and electrochemical polarization method.
Informatics for Combinatorial Experiments: Accelerating Data Interpretation
Authors: Stukowski M. , Suh C. , Rajan Krishna , D. Tall P. , C. Beye A. , G. Ramirez A. , O. Soboyejo W. , L. Benson M. , Liaw P.K. 
Published: April 2011

AbstractCombinatorial experiments provide a means of generating large amounts of experimental data; however that does not necessarily lead to high throughput interpretation of that data. In this paper we provide a brief summary of how one can use informatics techniques to accelerate data interpretation from high throughput experiments. We provide examples from high throughput nanoindentation and diffraction experiments.
Micro- to Nano-scale Structure and Drug Release Behavior of Solutions and Hydrogels of Poly (lactide)-Poly (ethylene oxide)-Poly (lactide) Triblock Copolymers
Authors: Agrawal Sarvesh Kumar , Sanabria-DeLong Naomi , Jemian Pete R. , Coburn Jeannine M. , Tew Gregory N. , Bhatia Surita R. 
Published: April 2011

AbstractWe have performed for the first time a complete structural characterization of PLA-PEO-PLA in the solution and hydrogel states. Previous studies on hydrogels of these polymers have shown that these gels have excellent mechanical properties suitable for possible application in tissue engineering and drug delivery. We have performed SANS, USAXS and confocal microscopy to relate the change in micro to nano scale self-assembled structure of these polymers in aqueous solution with changes in the block length and stereospecificity of the PLA block. A significant difference in structure and association behavior was seen between the polymers made from amorphous D/L-lactide as compared to those with crystalline L lactide blocks. In the former case spherical micelles were seen to form whereas the latter forms nonspherical polydisperse micellar assemblies. Both polymers form an associative network structure at higher concentrations, leading to gelation. USAXS and confocal microscopy show the presence of large-scale fractal aggregates in the hydrogels of these polymers. The fractal structure was denser for the L lactide series polymers as compared to the D/L-lactide series polymers. These results show that we can tune the microstructure and thereby the mechanical strength of these gels depending upon the specific application we need it for. We also show profiles for release of hydrophobic drug sulindac from 5 weight% solutions of these polymers in phosphate buffer saline. The profiles follows an almost zero order release behavior that continues slowly and steadily over several days and is again found to be strongly dependent on the crystallinity and molecular weight of the PLA block.
Nanocharacterization of Relaxation Properties in Organic Thin Film Electronic Materials
Authors: Gray Tomoko , Overney Rene 
Published: April 2011

AbstractWith increased molecular complexity of organic thin film electronics, novel characterization methods are required to provide nanoscale material property information. Particularly important in polymer thin film electronics are methods characterizing the mobility properties of materials that are in amorphous unsteady states. If the unsteady nature of materials is paired with dimensional and interfacial constraints in anisotropic systems, such as thin films, it produces material systems of great challenges with enormous engineering potentials. Two examples are addressed in this paper, involving desired and undesired supramolecular alignments in polymer thin films, the spectral stability in organic blue-light emitting diodes and the electro-optical (EO) activity in organic non-linear optical (NLO) materials, in conjunction with novel scanning probe microscopy (SFM) based characterization tools. The nanoscopic methods discussed here, i.e., shear modulation force microscopy (SM-FM), and nanoscale isothermal friction analysis (NIFA), offer a quantitative approach for investigating the mobility/stability of organic semiconductor polymer films. Thereby, local properties such as energy barriers for sub-molecular motions (relaxations) and critical transition temperatures can be directly inferred from organic films that are used in actual electronic devices.
Analysis of Electromigration- and Stress-Induced Dynamical Response of Voids Confined in Metallic Thin Films
Authors: Gungor M. Rauf , Cho Jaeseol , Maroudas Dimitrios 
Published: April 2011

AbstractA theoretical analysis based on self-consistent dynamical simulations is presented of electromigration- and stress-induced surface morphological response of voids confined in metallic thin films. The analysis predicts the onset of stable time-periodic states for the void surface morphological response, which is associated with current-driven wave propagation on the void surface. This time-periodic response is demonstrated under certain electromigration conditions and detailed response diagrams are presented which map the corresponding parameter space to regions of steady, time-periodic, and unstable surface morphological response. The evolution of the electrical resistance of these thin films also is computed, providing an interpretation for experimentally observed time-periodic response of the electrical resistance of metallic interconnect lines on the basis of current-driven void morphological evolution. In addition, we demonstrate significant effects on the electromigration-induced morphologically stable void migration of mechanical stress application in a metallic thin film. Specifically, we find that under certain electromechanical conditions, elastic stress can cause substantial retardation of void motion, as measured by the constant speed of electromigration-induced translation of morphologically stable voids. More importantly, this effect suggests the possibility for complete inhibition of void motion under stress.
Nanocrystalline gold and gold-palladium as effective catalysts for selective oxidation
Authors: Edwards Jennifer , Landon Philip , Carley Albert F. , Herzing Andrew , Watanabe Masashi , Kiely Christopher J. , Hutchings Graham 
Published: April 2011

ABSTRACTThe recent interest in oxidation catalysis provides the focus for this paper. Until recently gold has been overlooked as a key component of both homogeneous and heterogeneous catalysts. However, the observation in the 1980's that nanocrystalline gold supported on oxides was an effective catalyst for low temperature carbon monoxide oxidation has now captured the imagination of many researchers. At present low temperature carbon monoxide oxidation remains an intensely studied field, but in recent years increased emphasis has been placed on using gold catalysts for selective oxidation. For example the oxidation of alkanes, alkenes and alcohols have all been shown to be effective with gold based catalysts. In addition gold palladium catalysts have been shown to be very effective for the direct formation of hydrogen peroxide and this will be described in this paper.
Fabrication of Photonic Crystal Biosensors using Micro-molding of Nanoporous Glass
Authors: Block Ian D. , Chan Leo L , Cunningham Brian T 
Published: April 2011

ABSTRACTWe demonstrate a micro-molding method for submicron patterning of a low-index sol-gel nanoporous glass for the purpose of fabricating large-area (∼3”×”) label-free photonic crystal optical biosensors. SEM images show that the sol-gel exhibited minimal shrinkage and good substrate adhesion and depict precise and uniform pattern transfer over the fabricated area within the limits of measurement resolution. A unique characterization approach accurately and quickly revealed porous glass patterned over a large area with geometrical and material properties uniform within 1%. We suggest that this robust method is an excellent approach for photonic crystal sensor fabrication, and may also find applications in integrated optics and electronics.
The Relation between Catalytic Activity of CO Oxidation and Support Structure in Oxidation Catalysts using Gold Nanoparticles
Authors: Nagano Shiho , Tajiri Koji , Tai Yutaka 
Published: April 2011

ABSTRACTThiol-passivated gold nanoparticles were adsorbed on several kinds of support materials such as titania-coated silica aerogels and xerogels etc., and then the thiol was removed by heat treatment. The catalytic activity of the prepared composites for CO oxidation reaction was measured, and the effects of the support on the catalytic activity were investigated. Density of the supports, namely, whether aerogel supports or xerogel ones, hardly affected the catalytic activity. It was found that the catalysts having high catalytic activity could be obtained by this preparation method, even using the xerogels as the support. Calcination of the supports before adsorption of the gold nanoparticles affected the activity. The difference of the catalytic activity was observed between the composites with same gold nanoparticle size, so it was considered that the surface condition of the support materials affects the state of gold nanoparticles in composite.
Synthesis of water-soluble, magnetic Fe/Au nanoparticles
Authors: Brown Katherine A. , Wijaya Andy , Alper Joshua D , Hamad-Schifferli Kimberly 
Published: April 2011

ABSTRACTWe report the synthesis of water soluble, monodisperse Fe/Au bimetallic nanoparticles with an average diameter of 7nm. Synthesis involves simultaneous reduction of Fe3+ and Au3+ in water to yield bimetallic nanoparticles. The elemental content of Fe is 1.5%. Nanoparticles exhibit ferromagnetic behavior as measured by SQUID. These particles can be easily conjugated to thiolated DNA, as evidenced by mobility shifts in agarose gel electrophoresis. Nanoparticles heat in solution to temperatures above 40°C, indicating suitability for hyperthermia.
Parallel and Complementary Detection of Proteins by p-type and n-type Silicon Nanowire Transistor Arrays
Authors: Zheng Gengfeng , Patolsky Fernando , Lieber Charles M. 
Published: April 2011

ABSTRACTLabel-free, real-time, parallel and complementary electrical detection of proteins is demonstrated by p-type and n-type silicon nanowire field-effect transistors in the same arrays. Composed of hundreds of individually electrically addressable nanowire devices with highly sensitive and reproducible performances, these nanowire arrays can be controllably modified by monoclonal antibodies, and show discrete conductance changes characteristic of highly selective binding and unbinding of target proteins, such as prostate specific antigens (PSA), thus providing a general and powerful platform for high-throughput real-time parallel detection and rapid screening of libraries of biomolecules. Studies show that the PSA proteins can be routinely detected at femtomolar concentrations with high selectivity, and simultaneously incorporation of both p-type and n-type silicon nanowire devices enable discrimination against false positive/negative signals. The integrated complementary nanowire sensor arrays open up substantial opportunities for diagnosis and treatment of complex diseases such as cancer, detection of biological threats, and fundamental proteomic and biophysical studies.
Sub-micron Patterning on Polymer Films for Protein Arrays
Authors: Christman Karen L. , Requa Michael V. , Enriquez-Rios Vanessa D. , Mendes Paula , Stoddart J. Fraser , Turner Kimberley L. , Maynard Heather D. 
Published: April 2011

ABSTRACTPatterning proteins at the sub-micron and nanoscale has many uses, including fabrication of protein arrays for diagnostic and sensor applications. Many groups have reported micron scale protein patterns using photolithography; however, smaller scales have not been realized. In this study, we demonstrate sub-micron protein patterns using photolithography. Patterning is achieved by chemical transformation of pH-reactive polymer films. Site-specific immobilization of streptavidin within a protein resistant background is demonstrated. This methodology could be utilized for the development of high density proteins arrays for biotechnology applications.
Nanostructured alumina doped TiO2 ceramics for gas sensors
Authors: Choi Young Jin , Bandyopadhyay Amit , Bose Susmita 
Published: April 2011

ABSTRACTNanostructured TiO2 based ceramics were synthesized using citrate-nitrate auto combustion method with different concentrations of aluminum oxide as dopant. The powder x-ray diffraction data showed that synthesized TiO2 powders, pure as well as alumina doped TiO2 had anatase phase. Dopant concentration was varied between 0 and 15 wt%. Particle size analysis showed that the particle size was in the range of 50 to 80nm for nanosized TiO2 calcined between 600 and 800°C. Average particle size of doped powders was generally less than pure TiO2. BET specific average surface area was between 10 and 25 m2/g. Doping upto 10wt% alumina is not effective in retarding anatase crystallite growth. The resistance of Al doped TiO2 sample is found to be lower than that of pure TiO2. Al2O3 doped TiO2 sensor was found to be selective to CO sensing at an operating temperature of 600 °C.
Surface Stress Effects on the Elastic Behavior of Nanoporous Metals
Authors: Crowson Douglas A. , Farkas Diana , Corcoran Sean G. 
Published: April 2011

ABSTRACTAtomic scale computer simulations were used to investigate the surface stress induced deformation in nanoporous metals. A phase field model was used to generate digital nanoporous structures that are quantitatively similar to those created experimentally via dealloying. We analyze the important effects of surface relaxations on the macroscopic deformation in these samples as well as in small spherical clusters.
High Sensitive Optical Detection of Bio-Chemicals onto a Silicon Oxide Surface Based on Waveguide Mode
Authors: Fukuda Nobuko , Fujimaki Makoto , Awazu Koichi , Tamada Kaoru , Yase Kiyoshi 
Published: April 2011

ABSTRACTThis work presents high sensitive detection of specific adsorption of proteins onto a silicon oxide (SiOx) surface modified by molecules with a biotinyl-end group. We fabricated a SiOx waveguide by sputtering onto a thin gold film and measured the incident angle-dependence of reflectivity using a polarized He-Ne laser under total internal reflection condition. When the s-polarized light was irradiated to the SiOx waveguide (760 nm) coupled with a prism, the incident angle-dependence of reflectivity showed narrow dips due to excitation of the waveguide mode. The waveguide surface was modified by the molecules with the biotinyl-end group as a protein probe. Specific adsorption of streptavidin in a PBS buffer solution was monitored through time course of the reflectivity change at a constant incident angle, where the waveguide mode was excited. As compared with conventional SPR system using a gold surface, high sensitive detection of the specific adsorption was achieved. Additionally, we fabricated micro-patterned arrays of biotinyl-end layers onto the SiOx waveguide surface by micro-contact printing. Then we observed the specific adsorption behavior on the micro-patterned arrays by the imaging based on the waveguide mode using a CCD camera.
Synthesis of Bimetallic AuPt Nanoparticles in Aqueous Solution and Electrocatalytic Activity
Authors: Njoki Peter N. , Luo Jin , Jacob Aisley , Munawar Rizwan , Khan Bilal , Zhong Chuan-Jian 
Published: April 2011

ABSTRACTThe ability to control composition and size in the synthesis of bimetallic nanoparticles is important for the exploitation of the bimetallic catalytic properties. This paper reports recent findings of an investigation of the synthesis of gold-platinum (AuPt) bimetallic nanoparticles in aqueous solution via reduction of AuCl4− and PtCl42− using a combination of reducing and capping agents. In addition to characterization of the morphological properties of the AuPt nanoparticles using TEM and XRD, the electrocatalytic activity of the carbon-supported AuPt nanoparticle catalysts was also examined for oxygen reduction reaction (ORR) using the rotating disk electrode (RDE) technique. The findings have implications to the design of bimetallic nanoparticle catalysts for fuel cell reactions.
PZT and PLZT thin films on Cu substrates for dielectric and piezoelectric applications: Effect of processing atmosphere and film strain
Authors: Kim Taeyun , Srinivasan Sudarsan , Kingon Angus I 
Published: April 2011

AbstractPZT (52/48) and PLZT (7/65/35) thin films were prepared by chemical solution deposition (CSD) on Pt/SiO2/Si and Cu foil substrate, respectively. For PZT thin films on Pt/SiO2/Si substrates, pO2 control during thermal treatment affected both perovskite phase formation and orientation, but did not show significant impact on the ferroelectric and dielectric properties. When PLZT thin films (7/65/35) were prepared on Cu foil to tailor ferroelectric/dielectric properties, it was observed that ferroelectric and dielectric properties were significantly affected by the strains, possibly from the coefficient of thermal expansion (CTE) mismatch between PLZT and Cu foil during cooling after high temperature crystallization. It was also experimentally observed that, depending on the direction of applied strain, the PLZT films could be cycled between ferroelectric and paraelectric phases. It was suggested that PZT based thin films on base metal substrate requires very careful processing for optimized electrical performance.