Materials Literature
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The energy loss spectra of the rare earths are characterized by sharp M4,5 edges, the relative intensities of which are characteristic of the 4f-shell occupancy of the excited ion. For the light rare earths, the dependence of these relative peak heights on 4f-shell occupancy is quite pronounced. Thus they may be used…
Trans-polyacetylene is evidenced by surface enhanced Raman scattering (SERS) in diamond films prepared by hot filament assisted chemical vapor deposition from C${\mathrm{H}}_{4}$ and ${\mathrm{H}}_{2}$. The analysis of the Raman spectra for different excitation energies shows that the deposited trans-polyacetylene is…
Polymers end grafted to a surface have recently been shown to have an anomalously low effective friction coefficient ${\ensuremath{\mu}}_{b}$. To understand the origin of the observed reduction in friction, molecular dynamics simulations of polymers tethered at one end to a surface in a good solvent were carried out.…
Temperature and compositional dependence of the electrical transport properties of the nonconventional binary bismuth cuprate glasses are reported for the first time. It has been observed that the phonon assisted small polaron hopping model in the nonadiabatic regime is consistent with the data only at high temperatur…
The long range orientational order in the nematic phase of 4,4′-dimethoxyazoxybenzene (PAA) has been studied using small angle neutron scattering (SANS) from mixtures of protonated and perdeuterated molecules. Unlike spectroscopic methods, the determination of the complete set of orientational order parameters is, in…
Inelastic neutron scattering experiments are combined with infrared and Raman data to obtain a uniquely defined description of the intramolecular vibrations of three oligomers of polythiophene. Through refinement of ab initio force fields, the three vibrational spectra of each oligomer are simulated with remarkable ac…
In order to interpret the experimental results of the state resolved UV-laser-induced desorption of NO from NiO(100) (rotational and vibrational populations, velocity distributions of the desorbing NO molecules, etc.), we have performed ab initio complete active space self-consistent field (CASSCF) and configuration i…
Explicit formulas are derived for the sum rules for the frequency-dependent hyperpolarizability-diagonal-components. These are the counterparts to the Cauchy moments for the dynamic polarizabilities. The formulas allow for the frequency dependence of any nonlinear optical process to be expressed as a single general ex…
We describe a set of techniques for performing large scale ab initio calculations using multigrid accelerations and a real-space grid as a basis. The multigrid methods provide effective convergence acceleration and preconditioning on all length scales, thereby permitting efficient calculations for ill-conditioned syst…
The tensile strength of fused silica fibers is believed to approach its intrinsic value at low temperature, and modern experiments indicate very small, perhaps unmeasured, intrinsic dispersion in this strength. I consider the application of classical ``weakest link'' models to this problem in an attempt to determine t…
Reactive extrusion of polypropylene (PP)/ethylene–propylene–diene terpolymer (EPDM)/high-density polyethylene (PE) (80/10/10 by weight) blends were carried out using a corotating twin-screw extruder. The effects of peroxide and coagent concentrations and extruder rpm were studied in terms of rheological, morphological…
We present optical constants for glassy SiS 2 in the infrared that are of relevance for the hitherto unidentified 21 μm feature observed in the spectra of proto-planetary nebulae. Preparation and infrared spectroscopy were performed under inert conditions to prevent an oxidation of the samples. The laboratory spectra…
The thermal degradation of some plastisols [poly(vinyl chloride) and plasticizer mixtures] normally used in the toy industry was studied using a nonisothermal thermogravimetric technique. Some kinetic parameters such as activation energies are calculated according to some methods reported in the literature. A mathemat…
The thermolysis of 60/40 mixtures of polyethylene (PE) and polystyrene (PS) was investigated at temperatures below 440°C. Liquid yield from the mixture, 84.1%, was comparable to yields obtained with the individual polymers. The yields of styrene monomer, 57.1%, and α-olefins, 27.7%, increased over those obtained when…
PP/EPR binary and PP/(EPR/PE) ternary blends were prepared based on the viscosity ratio, using a corotating twin-screw extruder. Both fibrillar structures and particle-in-matrix morphologies were created depending on the viscosity ratio of rubber domain to the matrix PP (ηEPR/ηPP, or ηEPR-PE/ηPP). With fibril formatio…
To improve the mechanical properties of polypropylene (PP), some elastomers and fillers are used. The impact properties and tensile strength are affected by both the mineral additives and the polymer additives. There are also some changes in the thermal properties. To improve the interfacial adhesion, some low molecul…
A molecular-dynamics simulation is presented which explores the microscopic dynamics of a monatomic model glass. The investigated systems consist of up to 32000 atoms interacting via a Lennard-Jones potential. The normal-modes analysis has been used to determine the pattern of atomic displacements. Except for the high…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…