Materials Literature
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Monte Carlo simulations of mesogenic polymers have been performed for single and binary systems in the bulk and for pure components in constrained environments. An expanded ensemble formalism was employed to facilitate fluctuations of the number of particles in grand canonical, Gibbs, and pseudo-Gibbs ensemble simulat…
The study of dc and microwave (140 GHz) electrical conductivities using multifrequency electron-spin resonance in undoped and HCl-doped polyaniline is reported. The accidental quasi-three-dimensional (3D) charge hopping between the pinned and mobile small polarons dominates the bulk conductivity of the emeraldine base…
The temperature dependence of the dielectric constant and dissipation in potassium dihydrogen phosphate (KDP), its deuterated compound (DKDP), triglycine sulfate (TGS), and TGS doped with \ensuremath{\alpha}-alanine (LATGS) has been studied at various frequencies. It is found that the relaxation time of domain freezin…
Reflectivity spectra of ${\mathrm{CaMnO}}_{3}$ and ${\mathrm{LaMnO}}_{3}$ were measured in a wide photon energy region between 5 meV and 30 eV at room temperature. Using the conductivity spectra obtained from the Kramers-Kronig analysis, electronic structures of the manganese oxides were investigated. In particular, t…
We have performed plane-wave pseudopotential density-functional theory calculations on the stoichiometric and reduced ${\mathrm{TiO}}_{2}$ (110) surface, the 2\ifmmode\times\else\texttimes\fi{}1 and 1\ifmmode\times\else\texttimes\fi{}2 reconstructions of the surface formed by the removal of bridging-oxygen atoms, and…
The Kernel polynomial method (KPM) has been successfully applied to tight-binding electronic-structure calculations as an O(N) method. Here we extend this method to nonorthogonal basis sets with a sparse overlap matrix S and a sparse Hamiltonian H. Since the KPM method utilizes matrix vector multiplications it is nece…
We calculate ab initio the electronic states and the Born dynamical charge ${\mathrm{Z}}^{\mathrm{*}}$ of the alkaline-earth oxides in the local-density approximation. We investigate the trend of increasing ${\mathrm{Z}}^{\mathrm{*}}$ values through the series, using band-by-band decompositions and computational exper…
The design of biomaterials containing specific ligands on the surface offers the possibility of creating materials that can interact with and potentially control mammalian cell behavior. Biodegradable materials further provide the significant advantage that the polymer will disappear in vivo, obviating long-term negat…
Based on ab initio quantum-chemical methods, accurate calculations on small boron clusters ${\mathrm{B}}_{\mathrm{n}}$ (n=2--14) were carried out to determine their electronic and geometric structures. The geometry optimization with a linear search of local minima on the potential-energy surface was performed using an…
Aluminum doped zinc oxide (AZO) films are prepared by rf magnetron sputtering on glass or Si substrates using specifically designed ZnO targets containing different amount of Al2O3 powder as the Al doping source. The structural, electrical, and optical properties of the AZO films are investigated in terms of the prepa…
We study the luminescence of surface modified CdSe nanocrystallites. There has been much speculation as to the origin of the band edge emission in these quantum confined structures. Because of their large surface to volume ratios it has been suggested that the emission originates from surface-related states. However,…
In this article the supermolecular structure and mechanical properties of poly(acrylonitrile-acrylamide-acrylic acid)/poly(vinyl alcohol) [P(AN-AM-AA)/PVA] intermacromolecular complex formed through hydrogen bonding were studied by means of SEM, TEM, and mechanical property testing. The experimental results show that…
This article highlights chemical modifications like alkali treatment, dinitrophenylation, benzoylation, and benzoylation-acetylation carried out on an pineapple agrowaste leaf fiber (PALF). The parent and chemically modified PALF were characterized by FTIR spectra, pH measurement, and detection of nitrogen. The percen…
Natural rubber (NR) was blended in various ratios with 17 kinds of tackifiers, which were prepared from rosin and terpenes. The blends were heated to various temperatures (20–120°C) in order to investigate their miscibility. The blends were visually observed for transparency or opacity at each temperature and further…
In this article, nature derived collagen was mixed with chitosan and crosslinked by formaldehyde to form a homogeneous composite membrane. The microstructure of the composite was characterized by transmission electron microscopy and differential scanning calorimetry. Mechanical and swelling properties of the composite…
A coaxial nozzle was developed to achieve further control over the morphology of microparticles precipitated from solution by carbon dioxide as a compressed fluid antisolvent. The polymer solution was sprayed through the core of the nozzle and CO2 through the annulus. For the coaxial nozzle versus a standard nozzle, p…
Extensional, flow-induced crystallization (FIC) of a high-density polyethylene (HDPE) melt has been studied using a four-roll mill flow cell. Simultaneous measurement of the birefringence and scattering dichroism are used to quantify the crystallization process during and following transient flow deformation in planar…
We derive a continuum equation for the magnetization of a conducting ferromagnet in the presence of a spin-polarized current. Current effects enter in the form of a topological term in the Landau-Lifshitz equation . In the stationary situation the problem maps onto the motion of a classical charged particle in the fie…
The fracture and failure mode of α- and β-isotactic polypropylene (α-iPP and β-iPP, respectively) were studied in high speed (1 m/s) three-point bending tests on notched bars cut from injection-molded dumbbell specimens and compared. The fracture response of the notched Charpy-type specimens at room temperature (RT) a…
A new approach to chemical bonding is introduced in order to provide an improved understanding of the connection between basic quantum mechanics and the covalent pair bond. It's focus is on the fact that the energy of the bond is largely given by the kinetic energy of the electrons, while the Coulomb forces are only c…