Materials Literature
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We have investigated the effects of nanometer-sized silver particles on the optical properties of Eu3+ ions in SiO2 glass. Glass samples were prepared by the sol-gel method. The mean particle size and volume fraction of silver particles, which were estimated from UV-VIS absorption spectra using Mie-Drude theory modifi…
The electronic structure of various nickel oxides with nickel valence varying from 1+ to 3+ was investigated with the aim to find similarities and differences to the isoelectronic cuprates. Only if the Ni ions are forced into a planar coordination with the O ions can a $S=1/2$ magnetic insulator be realized with the d…
We present measurements of the lattice thermal conductivity ${\ensuremath{\kappa}}_{\ensuremath{\perp}}$ normal to the interfaces of $(\mathrm{GaAs}{)}_{n}/(\mathrm{AlAs}{)}_{n}$ superlattices with n between 1 and 40 monolayers. The conductivity was measured by an optical pump-and-probe technique in the temperature ra…
Electronic and magnetic properties of ribbon-shaped nanographite systems with zigzag and armchair edges in a magnetic field are investigated by using a tight-binding model. One of the most remarkable features of these systems is the appearance of edge states, strongly localized near zigzag edges. The edge state in a m…
An advanced heat-resistant fiber (trade name Ekonol) spun from a nematic liquid crystalline melt of thermotropic wholly aromatic poly(p-oxybenzoate-p,p′-biphenylene terephthalate) has been subjected to a dynamic thermogravimetry in nitrogen and air. The thermostability of the Ekonol fiber has been studied in detail. T…
The thermal degradation and kinetics of poly(2,6-dimethylphenylene oxide) (PPO) were studied by high-resolution thermogravimetry. The thermogravimetry measurements were conducted at an initial heating rate of 50°C min−1, resolution 4.0, and sensitivity 1.0 in both nitrogen and air from room temperature to 900°C. A two…
Using thermomechanical spectroscopy, the molecular-weight distribution and relaxation transitions have been investigated in commercial LDPE and grafted by itaconic acid (LDPE-g-IA). This grafting in the molten LDPE was done by reactive extrusion with varied content of reactants in the blend under alternating of a shea…
Molecular weight determination of 83% degree of deacetylation (DD) chitosan with non-Gaussian and broad molecular weight distribution by high-performance size exclusion chromatography (HPSEC) and by capillary viscometry were proposed. The relationships between weight average retention volumes (RVw) of HPSEC and intrin…
The chain extension reaction in poly(butylene terephthalate) (PBT) melt was studied in detail. A high-reactivity diepoxy, diglycidyl tetrahydrophthalate, was used as a chain extender that can react with the hydroxyl and carboxyl end groups of PBT at a very fast reaction rate and a relatively high temperature. A Haake…
Polymerization of ethylene in a CSTR using a combined metallocene catalyst system (combination of an open-face catalyst, such as Constrained Geometry Catalyst, and a conventional metallocene catalyst) was studied. Using the model developed by Soares and Hamielec, and expanded by Beigzadeh et al., a steady-state simula…
The thermal decomposition of polycarbonate (PC), PC containing resorcinol bis(diphenyl phosphate) (RDP), and PC—acrylonitrile–butadiene–styrene (PC–ABS) blend containing RDP was studied by thermogravimetry. Volatile and solid products of thermal decomposition were collected at different steps of thermal decomposition…
The tensile drawing behavior of quenched and annealed films of isotactic polypropylene is investigated as a function of draw temperature and strain rate. A strain-induced structural change from the smectic to the monoclinic form is observed for the quenched films. A kinetic interpretation is proposed for the phenomeno…
New nanocomposites are processed with a plasticized poly(vinyl chloride) matrix reinforced by cellulose whiskers whose characteristics are a high aspect ratio and a large interface area. Dynamic mechanical analysis performed on samples reinforced with a filler fraction of up to 12.4 vol % gives the viscoelastic proper…
Experimental solubilities are reported for anthracene dissolved in ternary 2-butoxyethanol + 1-propanol + 1-butanol, 2-butoxyethanol + 1-propanol + 2-butanol, 2-butoxyethanol + 2-propanol + 1-butanol, and 2-butoxyethanol + 2-propanol + 2-butanol solvent mixtures at 25 °C and atmospheric pressure. For each of the four…
A series of codoped nanocrystalline ceria compositions, Ce 1 - x M x Bi 0.4 O 2.6 - x (M = Ca, Sr, and Ba; x = 0.01−0.15) were hydrothermally synthesized at 240 °C and characterized by powder X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. All as-made Ce 1 - x M x Bi 0.4…
Two novel, isostructural, one-dimensional tellurites of molybdenum(VI), (NH 4 ) 4 Mo 6 TeO 22 ·2H 2 O and Rb 4 Mo 6 TeO 22 ·2H 2 O, have been synthesized by hydrothermal method. They contain linear (Mo 6 TeO 22 ) 4 - anionic chains, parallel to one another and held together by NH 4 + /Rb + ions. “Mo 6 O 22 ” moieties,…
In this paper, the nonlinear dynamics of a new Shape Memory Alloy (SMA) actuator that possesses impressive payload lifting capabilities are presented. This actuator consists of 48 SMA wires mechanically bundled in parallel forming one powerful muscle. It was designed to lift up to 45.4 kg (100 lbs), which is approxima…
Complex formation between small carboxyl-terminated dendritic polymers and oppositely charged poly(dimethyldiallylammonium chloride) was monitored by turbidimetry, dynamic light scattering, viscometry and potentiometric titration. All techniques reveal a discontinuity at a well-defined pH, corresponding to the point o…
We have used neutron reflection to study the effects of pH and added electrolyte on the structure of a weak polyelectrolyte brush anchored by means of a hydrophobic block to a hydrophobic surface. The copolymer was poly(2-(dimethylamino)ethyl methacrylate- block -methyl methacrylate) (poly(DMAEMA- b -MMA)) containing…
The oxidation of various para-substituted phenyl methyl sulfoxides with several substituted oxo(salen)manganese(V) complexes follows an overall second-order kinetics that is first-order in sulfoxide and in oxo(salen)manganese(V) complex. Electron-releasing substituents in sulfoxides and electron-withdrawing substituen…