Periodic Hartree-Fock linear combination of crystalline orbitals calculation of the structure, equation of state and elastic properties of titanium diboride
The use of titanium diboride to protect the cathodes of aluminum electrolysis cells G
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Synthesis and Characterization of Hyperbranched Aromatic Poly(ether imide)s with Varying Degrees of Branching
A series of high molecular weight hyperbranched poly(ether imide)s (HBPEI), derived from the AB 2 monomer N -[3,5-di( tert -butyldimethylsilyloxy)phenyl]-4-fluorophthalimide ( 1 ), were synthesized in a single-step process involving a rapid fluoride-catalyzed arylation reaction. NMR analysis of the degree of branching…
Spontaneous Organization of Supramolecular Rod-Bundles into a Body-Centered Tetragonal Assembly in Coil−Rod−Coil Molecules
The synthesis and characterization of coil−rod−coil molecules of 4,4‘-bis[4-methyloxypoly(propyleneoxy)propyloxy-4‘-biphenyloxymethyl]biphenyl with a poly(propylene oxide) coil of 3 ( 7 ), 6 ( 8 ), 9 ( 9 ), 13 ( 10 ), 17 ( 11 ), and 22 ( 12 ) propylene oxide units are described. These molecules self-assemble into orde…
Glass transition temperatures of hydrocarbon blends: Adhesives measured by differential scanning calorimetry and dynamic mechanical analysis
A comparison of calculated and measured glass transition temperatures of a series of three-component hydrocarbon blends was performed. The blends were prepared as mixtures of an elastomer with different proportions of tackifying resin and oil. Glass transition temperature, Tg, was measured by differential scanning cal…
Phase separation mechanism during membrane formation by dry-cast process
Phase separation mechanisms during the membrane formation by dry-cast process were investigated by light scattering in the cellulose acetate/dimethylformamide (DMF)/2-methyl-2,4-pentanediol system. Phase separation occurred by spinodal decomposition (SD) when paths of the composition changes due to the evaporation of…
Crystal structure of the NADP+-dependent aldehyde dehydrogenase from Vibrio harveyi: structural implications for cofactor specificity and affinity
Aldehyde dehydrogenase from the bioluminescent bacterium, Vibrio harveyi, catalyses the oxidation of long-chain aliphatic aldehydes to acids. The enzyme is unique compared with other forms of aldehyde dehydrogenase in that it exhibits a very high specificity and affinity for the cofactor NADP(+). Structural studies of…
Porous Silicon Carbide Sintered Substrates for High-Temperature Membranes
Silicon carbide (SiC) porous substrates are prepared by pressureless sintering of SiC powders under an inert atmosphere of argon. The porous SiC substrates were characterized by measuring their porosity, pore size distribution, surface characteristics, and structure. Their transport characteristics were investigated u…
Studies of crosslinked styrene-alkyl acrylate copolymers for oil absorbency application. II. Effects of polymerization conditions on oil absorbency
Crosslinked styrene–acrylate copolymers were synthesized and evaluated by swelling properties for oil-absorbency application. The effect of various polymerization conditions (crosslinking agent concentration, initiator concentration, monomer concentration, and polymerization temperature) were studied through oil-absor…
Electronic structure and magnetism in disordered bcc Fe alloys
We here study electronic structure and magnetic properties of bcc Co$_{x}$Fe$_{1-x}$, Cr$_{x}$Fe$_{1-x}$ and Mn$_{x}$Fe$_{1-x}$ in their ferromagnetic phases using Augmented Space Recursion technique coupled with tight-binding linearized muffin tin orbital (TB-LMTO) method. We make a systematic study of magnetic prope…
Distinct Formation of a Chiral Smectic Phase in Achiral Banana-Shaped Molecules with a Central Core Based on a 2,7-Dihydroxynaphthalene Unit
We have prepared a novel series of banana-shaped molecules with a central bent core based on a 2,7-dihydroxynaphthalene group, the side wings containing a Schiff's based moiety, and alkoxy flexible tails with carbon numbers n = 6, 8, 10, 12, 14, and 16. Among these, the molecules with n = 8−16 formed a novel smectic p…
Kinetic and thermodynamic control of protein adsorption
Control of nonspecific protein adsorption is very important for the design of biocompatible and biomimetic materials as well as drug carriers. Grafted polymer layers can be used to prevent protein adsorption. We have studied the molecular factors that determine the equilibrium and kinetic control of protein adsorption…
Transparent Superhydrophobic Thin Films with Self-Cleaning Properties
Transparent superhydrophobic thin films with TiO 2 photocatalyst were prepared by utilizing a sublimation material and subsequent coating of a (fluoroalkyl)silane. The transparency of the films decreased with increasing TiO 2 concentration, which was attributed to the size difference of the starting materials. The fil…
Raman study of ZnxBe1−xSe alloy (100) epitaxial layers
Long wavelength longitudinal optical (LO) and transverse optical (TO) phonons of BeSe and ZnxBe1−xSe layers are identified in a wide composition range by using Raman spectroscopy. A two-mode behavior is clearly evidenced. As predicted by the dielectric model of Hon and Faust, the eigenfrequencies of the BeSe- and ZnSe…
Tubes of rhombohedral boron nitride
The structure of boron nitride bamboo-like tubular whiskers grown from boron nitride powder is investigated by high-resolution transmission electron microscopy. Despite the relatively small size of the tubes (20-200 nm in diameter), they all exhibit rhombohedral-like ordering in their layer stacking. The tubular sheet…
Surface electronic phase transition in colossal magnetoresistive manganese perovskites: La0.65Sr0.35MnO3
We have observed a distinct surface phase transition for an important class of giant magnetoresistance materials [La1−xSrxMnO3(x=0.35)]. The surface phase transition occurs at 240 K compared to 370 K for the bulk and is fundamentally different. In the bulk, a ferromagnetic metal to paramagnetic bad-metal transition oc…
Dielectric studies of dipolar relaxation processes in nylon 11
The dielectric properties of semicrystalline nylon 11 (mixture of γ and α phase, degree of crystallinity 62%) were investigated in wide ranges of frequency and temperature by broadband dielectric relaxation spectroscopy, thermally stimulated depolarization current techniques and triangular voltage measurements. The ma…
Origin of Dynamic Heterogeneities in Miscible Polymer Blends: A Quasielastic Neutron Scattering Study
In order to investigate the origin of the often invoked nanoheterogeneities in miscible polymer blends, we have performed quasielastic neutron scattering experiments on the component dynamics within the miscible polymer blend polyisoprene/polyvinyl ether including the pure components as a reference. We find that the a…
Biexciton emission from high-quality ZnO films grown on epitaxial GaN by plasma-assisted molecular-beam epitaxy
We have investigated the optical and structural properties of high-quality ZnO films grown on epitaxial GaN (epi-GaN) by plasma-assisted molecular-beam epitaxy employing low-temperature buffer layers. High-resolution x-ray diffraction for both symmetric and asymmetric reflexes shows that crystalline defects in ZnO fil…
Visible emission from electroluminescent devices using an amorphous AlN:Er3+ thin-film phosphor
Electroluminescence (EL) studies of AlN:Er alternating-current thin-film electroluminescent (ACTFEL) devices were performed at 300 K. Thin films of Er-doped AlN, ∼200 nm thick, were grown on indium–tin–oxide/aluminum–titanium–oxide/glass substrates using rf magnetron sputtering in a nitrogen atmosphere. The turn-on vo…
New Mechanism for Electron Emission from Planar Cold Cathodes: The Solid-State Field-Controlled Electron Emitter
A new mechanism for electron emission from planar cathodes is described. The theoretical analysis shows that, with an ultrathin wide band-gap semiconductor layer (UTSC) on a metal, the surface barrier is lowered to approximately 0.1 eV due to the creation of a space charge induced by the electrons injected from the me…