Materials Literature
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The use of Y zeolite supported Ni to grow ordered carbon nanofibers from an ethylene/hydrogen feedstock has been investigated where Ni was incorporated into the aluminosilicate framework by ion exchange and impregnation; the action of the Ni/NaY zeolites is compared with that of Ni/SiO 2 of comparable Ni loading prepa…
Abstract Polyethylene (PE) and polypropylene (PP) were reacted with benzoyl peroxide (BPO) and 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO) to prepare PE‐TEMPO and PP‐TEMPO macroinitiators, respectively. Molecular weight of PP decreased, whereas that of PE increased during the reaction with the BPO/TEMPO system. Polys…
Some new characterization results are reported for composites prepared from methyl acrylate monomer and from reinforcing silica particles at various degrees of dispersion. In some cases, 3-(trimethoxysilyl)propyl methacrylate groups were grafted onto the silica (PMA) through participation in the methyl acrylate polyme…
The members of the enolase superfamily catalyze different overall reactions, yet share a partial reaction that involves Mg(2+)-assisted enolization of the substrate carboxylate anion. The fate of the resulting enolate intermediate is determined by the active site of each enzyme. Several members of this superfamily hav…
Zn 2 SiO 4 :Mn 2+ nanocrystals were grown in an oxidized porous silicon layer using a chemical impregnation method. Apparently two classes of samples have been obtained. One is characterized by the formation of α-phase zinc silicate crystalline particles, which show green luminescence, and the other one is characteriz…
Amphiphilic NaY zeolite particles were prepared by a partial modification of the external surface of NaY with alkylsilyl groups. When the particles were added to a mixture of aqueous hydrogen peroxide and normal alkene, they were feasibly located just at the liquid−liquid phase boundary and efficiently catalyzed epoxi…
Abstract The relationship between the molecular structure and the thermal and rheological behaviors of metallocene‐ and Ziegler–Natta (ZN)‐catalyzed ethylene copolymers and high‐density polyethylenes was studied. Of special interest in this work were the differences and similarities of the metallocene‐catalyzed (homog…
This paper details the design and fabrication of millimeter-scale solid propellant rockets for one-time deployment of wireless sensor platforms, known as Smart Dust. Each microrocket assembly is an integrated system, incorporating a combustion chamber, composite propellant grain, nozzle, igniter, and thermoelectric po…
Abstract Pb particles on a Si(111) substrate were investigated using a photoemission electron microscope (PEEM). The electrons have been excited by a linearly polarised femtosecond laser beam with a wavelength of λ = 400 nm. The PEEM images exhibit an unusually high contrast. They arise due to photoemission being of a…
Abstract The decomposition mechanism of 2‐ethyl‐hexylnitrate (2‐EHN), an important additive to diesel fuel to improve the cetane number, was investigated in solution and in the gas phase. In trans ‐decalin as solvent, an activation barrier for the thermal decomposition of 39 kcal/mol was determined, and thus the decom…
The kinetics of hydroxyapatite (HAP) crystallization, which is thermodynamically the most stable calcium phosphate salt, has been investigated at physicochemically defined physiological conditions. The crystal growth process involved metastable supersaturated solutions, and for the study the constant composition metho…
Diarylethenes having two nitronyl nitroxide radicals at both ends of the molecule with oligothiophene spacers were synthesized. The diradicals underwent photochromic reactions upon alternate irradiation with UV and visible light. ESR spectra of the diradicals reversibly changed with the photochromism. The magnetic int…
Excitation and emission spectra of CdSe single quantum rods with aspect ratios of 2 and 4 were investigated by far-field microscopic technique. Typical spectral linewidths of the rods are less than 60 meV at room temperature. Both excitation and emission of the single rods exhibit strong polarization dependence, indic…
Tetraazamacrocyclic ligands have been prepared in which three of the four nitrogen atoms are functionalised with carboxylate donors and the fourth is alkylated with a para-substituted acetophenone group {–CH2C(O)C6H4–X, where X = H, OMe, NMe2}. The europium(III), gadolinium(III) and (for X = H) terbium(III) complexes…
We report a detailed experimental and theoretical investigation of the Fermi-surface topology of the layered transition-metal dichalcogenide $2H\ensuremath{-}{\mathrm{NbSe}}_{2},$ which undergoes a second-order phase transition into an incommensurate two-dimensional charge-density-wave phase at 33.5 K. High-resolution…
The C $1s$ and N $1s$ core levels of carbon nitrides are composed of several contributions whose assignment is controversial due to the lack of appropriate reference materials and the great variety of configurations of carbon and nitrogen. From the comparison of nitrogen-containing polymeric compounds and solid carbon…
Proteins directly control the nucleation and growth of biominerals, but the details of molecular recognition at the protein-biomineral interface remain poorly understood. The elucidation of recognition mechanisms at this interface may provide design principles for advanced materials development in medical and ceramic…
We investigate the anomalous dynamics of unentangled polymer melts. The proposed equation of motion formally relates the anomalous center-of-mass diffusion, as observed in computer simulations and experiments, to the nature of the effective intermolecular mean-force potential. An analytical Gaussian-core form of the p…
Thermal expansion coefficient in single-walled carbon nanotube bundles was determined as $(\ensuremath{-}0.15\ifmmode\pm\else\textpm\fi{}0.20)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5} (1/\mathrm{K})$ for the tube diameter and $(0.75\ifmmode\pm\else\textpm\fi{}0.25)\ifmmode\times\else\texttimes\fi{}{10}^…
Mechanism for acceleration of phase separation in Fe-base ternary alloys was investigated with use of a model based on the Cahn-Hilliard equation. Behavior of the minor element in an Fe-base ternary alloy along the trajectory of the peak of the major element is dependent on the sign of the second derivative of the che…