Materials Literature
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Recent numerical developments in the study of glassy systems have shown that it is possible to give a purely geometric interpretation of the dynamic glass transition by considering the properties of unstable saddle points of the energy. Here we further develop this approach in the context of a mean-field model, by ana…
We formulate a theory of double perovskite compounds such as ${\mathrm{Sr}}_{2}{\mathrm{FeReO}}_{6}$ and ${\mathrm{Sr}}_{2}{\mathrm{FeMoO}}_{6}$ which have attracted recent attention for their possible uses as spin valves and sources of spin-polarized electrons. We solve the theory in the dynamical mean-field approxim…
One of the main obstacles to the use of alkaline-earth-oxide-based NO x adsorbents for emissions control is the ready poisoning of these materials by SO x . To shed light on the mechanisms of poisoning, density functional theory (DFT) calculations and infrared spectroscopy experiments are used to study SO x adsorption…
The synthesis of polyphosphazene- co -poly(ethylene oxide) block copolymers with well-defined molecular weights has been accomplished via end-functionalized polymer intermediates. Mono- and diamine-terminated poly(ethylene oxides) (PEO = (CH 2 CH 2 O) n −CH 2 CH 2 −) were used to produce polymer-based phosphoranimines…
The relaxation dynamics of a low molecular supercooled liquid, cresolphthalein-dimethylether (KDE), has been investigated in the vicinity of glass transition temperature by dielectric relaxation measurements. Glass transition is approached and studied by the use of isothermal and isobaric paths. Under isobaric conditi…
A novel NO x control technique based on the utilization of iron-containing compounds was studied. Iron-containing additives can be injected in small amounts either into the combustion zone or, if reburning is used, into the reburning zone to reduce NO x emissions. Tests in a 300-kW Boiler Simulator Facility demonstrat…
The viscosity and electrical conductivity and the ${}^{27}\mathrm{Al}$ spin-lattice relaxation time have been measured for two calcium aluminosilicate liquids or glasses. At high temperature, the relaxation times for the three processes are the same to within experimental errors. This similarity points to a coupling b…
The potential energy surfaces of several model atomic glass formers have been studied using eigenvector-following techniques. Barrier distributions, cooperativity indices, path lengths, and vibrational densities of states (VDOS) are presented based upon data sets containing more than 250 000 pathways in total. We find…
We have fabricated multiwalled carbon nanotubes (CNTs) with flowing acetylene, using a well-ordered porous anodic aluminum oxide (AAO) nanotemplate with or without deposition of Co in the pores as a catalyst. Without deposition of Co, the tubes were made in the pores having the shape of the pores by catalysis with the…
Magnetoresistive effects $(R(0)\ensuremath{-}R(H))/R(H)$ exceeding $500%$ are found at room temperature in a field of 7 mT in nanocontacts between ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ crystallites. The shape of the $I(V)$ curve depends on field and the magnitude of the magnetoresistance is correlated with the resistanc…
We report measurements of the transport and the magnetic properties of high-quality, sub-millimeter-sized MgB2 single crystals with clear hexagonal-plate shapes. The low-field magnetization and the magnetic hysteresis curves show the vortex pinning of these crystals to be very weak. The Debye temperature of $Θ_{D}\sim…
Abstract A model polyethylene‐poly( L ‐lactide) diblock copolymer (PE‐ b ‐PLLA) was synthesized using hydroxyl‐terminated PE (PE‐OH) as a macroinitiator for the ring‐opening polymerization of L ‐lactide. Binary blends, which contained poly( L ‐lactide) (PLLA) and very low‐density polyethylene (LDPE), and ternary blend…
Density functional theory (DFT) electronic structure calculations were carried out to predict the structures and ground-state spectra for zinc complexes of porphyrin (ZnP), tetraazaporphyrin (ZnTAP), tetrabenzoporphyrin (ZnTBP), and phthalocyanine (ZnPc). All four porphyrins are found to have stable D4h structures. St…
We used near-edge x-ray absorption fine structure (NEXAFS) spectroscopy to link the orientational bond order at three carbonaceous surfaces-rubbed polyimide, ion beam-irradiated polyimide, and ion beam-irradiated diamondlike carbon films-with the direction of liquid crystal (LC) alignment on these surfaces. We show th…
We have observed very large tunneling magnetoresistance (TMR) in epitaxially grown ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}/\mathrm{AlAs}/{\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ ferromagnetic semiconductor tunnel junctions. Large TMR ratios more than $70%$ (maximum $75%$) wer…
The discovery of periodic mesoporous MCM-41 and related molecular sieves has attracted significant attention from a fundamental as well as applied perspective. They possess well-defined cylindrical/hexagonal mesopores with a simple geometry, tailored pore size, and reproducible surface properties. Hence, there is an e…
Central to the concept of seed-mediated growth of nanoparticles is that small nanoparticle seeds serve as nucleation centers to grow nanoparticles to a desired size. We have examined this common assumption in a model system, the wet chemical synthesis of gold nanoparticles via reduction of a gold salt, by transmission…
The structure of the free-acid form of the coenzyme NAD(+) was determined at 100 K from a single-crystal neutron experiment. NAD(+) is the oxidized form of the coenzyme redox pair NAD(+)/NADH and plays an important role in the catalysis of biological processes. The molecule crystallizes in space group P1 with one NAD(…
The potassium salt of poly(trimethylene-1,1-dicarboxylic acid), the first member of a new polyelectrolyte family where the carbon backbone is substituted on every third carbon by two carboxylate anions, was obtained by hydrolysis of a monodisperse di- n -propyl ester polymer (CH 2 CH 2 C(COO n Pr) 2 ) n . This precurs…
Two poly(pyridinium salt)s containing tosylate as a counterion were synthesized by the ring-transmutation polymerization reaction of bis(pyrylium tosylate) with the corresponding aromatic diamines and characterized for their lyotropic liquid-crystalline as well as fluorescence properties in both polar protic and aprot…