Materials Literature
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The role of chain length in affecting the molecular organization in thin films of mesogenic Zn−porphyrin octaesters ZnC n OAP has been investigated by means of Langmuir isotherms and area-per-molecule relaxation measurements at the air−water interface, as well as by unpolarized and polarized optical absorption spectro…
The synthesis of polyurethane polymers in the presence of diisopropylfluorophosphatase (DFPase) has enabled the irreversible attachment of the enzyme to the polymeric matrix. The resulting bioplastic hydrolyzes diisopropylfluorophosphate (DFP) in buffered media up to 67% of the rate for the same amount of soluble enzy…
Temperature-programmed desorption (TPD) of benzene on Si−MCM-41, Na−AlSi−MCM-41, and H−AlSi−MCM-41 mesoporous materials from 323 to 673 K at different linear heating rates (5, 10, 20, and 25 K min - 1 ) and that on Si−MCM-41 at different adsorbate loadings (0.45−10.7 μmol g - 1 ) has been investigated. 1 H− 29 Si cros…
The bi- and trinuclear mixed-valence complexes [{Cp*(dppe)Fe(CC−)} 2 (1,3-C 6 H 4 )][PF 6 ] ( 2 + ), [{Cp*(dppe)Fe(CC−)} 3 (1,3,5-C 6 H 3 )][PF 6 ] ( 3 + ), and [{Cp*(dppe)Fe(CC−)} 3 (1,3,5-C 6 H 3 )][PF 6 ] 2 ( 3 2+ ) were prepared either by oxidation of [{Cp*(dppe)Fe(CC−)} 2 (1,3-C 6 H 4 )] ( 2 ) or [{Cp*(dppe)Fe(CC…
The transition from solid to liquid during the melting of a semicrystalline polymer can be viewed as reverse gelation since the physical gel point (state of liquid-to-solid transition) is approached from the solid side. In this study we explore routes of stopping the melting process at the gel point and stabilizing th…
Polyradicals comprised of m-phenylene-bridged organic radicals are well known as building blocks of organic ferromagnets, in which radical groups are connected with each other at the meta position in the benzene ring, and the parallel-spin configurations between radical sites are more stabilized than the antiparallel…
The structure and vibrational spectra of kaolinite have been investigated by the joint use of vibrational spectroscopic techniques and of computational methods. The derived potential is based on ab initio calculations of molecular models and tested in normal mode analyses and molecular dynamics simulations. The calcul…
Most advanced oxidation processes (AOP) readily decolorize but are unable to mineralize aqueous azo dye solutions. The extent of mineralization measured as total organic carbon (TOC) losses during the 500-kHz sonication of azobenzene or methyl orange solutions increases from 20% to more than 80% in the presence of O 3…
Density Functional Theory (DFT) is utilized to compute field-dependent binding energies and intramolecular vibrational frequencies for carbon monoxide and nitric oxide chemisorbed on five hexagonal Pt-group metal surfaces, Pt, Ir, Pd, Rh, and Ru. The results are compared with corresponding binding geometries and vibra…
Magnetization reversal in a fine ferromagnetic grain is simulated for the case of an instantaneously applied reversal magnetic field. The Hamiltonian of the system contains the exchange interaction, the uniaxial anisotropy, the Zeeman energy and the dipole-dipole interactions. A cubic grain is discretized into 64 cubi…
We have computed the variation of the vacancy formation energy with pressure for Ta. Total energy calculations were performed for 16 and 54 atom supercells using a mixed basis pseudopotential method which uses pseudo-atomic orbitals and low energy plane waves as the basis set, within density functional theory (LDA and…
Submicron-sized colloidal particles have been self-organized into patterned arrangements on a substrate using a novel technique. At the substrate, a polyelectrolyte multilayer film has been deposited onto a chemically patterned surface; subsequently, the polyelectrolyte surface is immersed in an aqueous colloidal susp…
The electronic spectra of carbon nanotubes and other nanoscale systems are quantized because of their small radii. Similar quantization in the phonon spectra has been difficult to observe because of the far smaller energy scale. We probed this regime by measuring the temperature-dependent specific heat of purified sin…
In concentrated glucose glasses with water contents between 10 and 30 wt %, an indication for a transition in mobility of the sugar protons above the glass transition temperature is observed, using proton magnetic resonance techniques. The first transition in mobility is positioned at the glass transition temperature…
The electrochemical behavior of cobalt 5,10,15,20-tetrakis ( α, α, α, α-2-pivalamidophenyl)porphyrin (Co II TpivPP) was examined in benzonitrile solutions. The electrochemical responses were changed significantly by the addition of 1-methylimidazole which coordinates once to the Co(II) and twice to the Co(III) porphyr…
The novel dendrimers consisting of a pi-conjugated backbone, the dendritic polyphenylazomethines (DPAs), were synthesized by the convergent method via the dehydration of aromatic ketones with aromatic amines in the presence of titanium(IV) tetrachloride. The obtained DPAs have a high solubility unlike the conventional…
The effects of chain end modification on freely standing amorphous polyethylene thin films with a thickness 2 R g to 4 R g (radius of gyration) are studied by a Monte Carlo (MC) simulation on a high coordination lattice. The rotational isomeric state (RIS) model is incorporated into the simulation as short-range inter…
A procedure for obtaining hydromagnesite is described. The process involves the formation of a Mg(HCO 3 ) 2 solution by carbonation of a MgO-containing residue slurry and further precipitation of hydromagnesite by addition of pure magnesium oxide as the precipitating agent. The solid residues generated can be landfill…
Microwave irradiation of racemic cis -[Ru(bpy) 2 (Cl) 2 ] (bpy = 2,2‘-bipyridine) or racemic cis -[Ru(phen) 2 (Cl) 2 ] (phen = phenanthroline) with either ( R )-(+)- or ( S )-(−)-methyl p -tolyl sulfoxide yielded the ruthenium bis(diimine) sulfoxide complexes with a high level of asymmetric induction (73−76% de). Ster…
The reaction of benzaldehyde with excess pyrrole at room temperature in the absence of solvent affords a mixture of meso-substituted polypyrranes species. After separation by column chromatography, these may be used to prepare a range of calix[4]phyrin macrocycles by condensation with acetone under conditions of acid…