Materials Literature
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A new family of porous inorganic solids based on nanocrystalline metal oxides is discussed. These materials, made up of 4-7 nm MgO, CaO, Al2O3, ZnO, and others, exhibit unparalleled destructive adsorption properties for acid gases, polar organics, and even chemical/biological warfare agents. These unique sorption prop…
We show that the transition in AMnO3 from the orthorhombic perovskite phase to the hexagonal phase is promoted by inducing disorder on the A-site. The gap between the orthorhombic and the hexagonal phase is widened for disordered, mixed yttrium-gadolinium manganite samples. At the cost of the orthorhombic phase a two…
In this era of molecular biology, protein crystallization is often considered to be a necessary first step in obtaining structural information through X-ray diffraction analysis. In a different light, protein crystals can also be thought of as materials, whose chemical and physical properties make them broadly attract…
Theoretical work has so far focused on the role of host-element chemical potentials in determining defect formation energies that control doping levels in semiconductors. Here, we report on our analysis of the role of the dopant-impurity chemical potential, which depends on the source gas. We present first-principles…
The meso substituted Ni(II)(5,15-diNO 2 −octaethylporphyrin) coexists in at least three different conformers in CS 2 . To explore the structural properties of these conformers, we measured the resonance excitation profiles and depolarization ratio dispersions of various prominent Raman lines of Ni(5,15-diNO 2 −octaeth…
Self-assembled monolayers on mesoporous supports (SAMMSs) have been found to be superior sorbent materials for sequestering environmentally problematic species. Coupling the rich coordination chemistry of transition metal complexes with the SAMMS concept has afforded anion-specific sorbent materials with unprecedented…
Static and time-resolved optical measurements have been performed on a number of free-base and zinc dodecaarylporphyrins with varying degrees of fluorination of the peripheral aryl rings. These studies were performed in a variety of solvents of differing polarity and metal-ligating ability and at room and low temperat…
Desorption/ionization on porous silicon (DIOS) is a relatively new laser desorption/ionization technique for the direct mass spectrometric analysis of a wide variety of samples without the requirement of a matrix. Porous silicon substrates were fabricated using the recently developed nonelectrochemical H2O2-metal-HF e…
A systematic theoretical study using the density functional theory is performed to provide molecular-level understanding on the desorption of carbon monoxide from surface oxygen complexes that are formed in the gasification and combustion of coal. Particularly, a CO molecule release from carbonyl oxygen complexes in t…
We present a simple set of data structures, and a collection of methods for constructing and updating the structures, designed to support the use of cohesive elements in simulations of fracture and fragmentation. Initially all interior faces in the triangulation are perfectly coherent, i.e., conforming in the usual fi…
In this work, silver film over silica nanosphere (AgFON) surfaces are shown to be thermally stable, SERS-active substrates that are suitable for use in ultrahigh vacuum (UHV) conditions. The metal FON surface is a materials general, cost-effective, and highly SERS-active surface. The SERS activity and thermal stabilit…
We propose a mechanism of long-range coherent coupling between nuclear spins to be used as qubits in solid-state semiconductor-heterojunction quantum information processing devices. The coupling is via localized donor electrons which in turn interact with the two-dimensional electron gas. An effective two-spin interac…
The interactions of hydrogen with ceria have been the subject of several experimental studies, but whether hydrogen atoms enter the bulk or are merely chemisorbed on the surfaces is disputed. We combine first-principles calculations with thermodynamic arguments and conclude that the uptake of small amounts of hydrogen…
In this study, we have explored the first use of the siliceous MCM-41 molecular sieve as an additive to enhance the gas permeability characteristics of a high-performance polysulfone. For all gases tested (N 2, O 2, CO 2, CH 4 ), the permeability increased in proportion to the weight percent of MCM-41 present in the f…
Abstract Homopolymers of itaconic acid (PIA) and its copolymers with acrylamide (P(IA‐AAm) were synthesized using ceric ammonium nitrate (NH 4 ) 2 Ce(NO 3 ) 6 in combination with nitrilotriacetic acid (NTA) as redox initiator, and potassium persulphate at pH 1. The chain structures of the resulting products have been…
A pressure cell with an anvil made of sapphire and the other made of tungsten carbide, was constructed to process thin film samples using a high power Nd:YAG pulsed laser, in a regime of ultrafast quenching rate and confined geometry. The sapphire anvil worked as the optical window to the laser beam and also as a good…
We investigated the influence of grinding as a pretreatment prior to the emitter film formation of single-walled carbon nanotubes (SWNTs) on the field emission and the geometric properties of SWNTs. Field emission from emitter films composed of ground SWNTs was found to be dramatically enhanced as well as to be homoge…
Abstract The chemical modification of native wheat straw hemicelluloses with succinic anhydride using N,N ‐dimethylformamide/lithium chloride system as solvent and pyridine and/or 4‐dimethyaminopyridine as catalyst has been examined. In particular, the progress of the succinoylation reaction is studied as a function o…
Ultrasonic attenuation due to phonon-phonon interaction and thermoelastic relaxation are studied in Lanthanum Monochalcogenides in <110> direction at different higher temperatures. For evaluation of ultrasonic absorption coefficients the second and third order elastic constants (SOEC) and (TOEC) are also calculated. S…
Photoluminescence and Raman scattering experiments were performed on Si/SiO2 superlattices grown by radio frequency magnetron sputtering on Si, quartz and glass substrates. Increasing the Si layer thickness in the Si/SiO2 superlattice gave rise to an increased photoluminescence signal and a Raman signature for nanocry…