Materials Literature
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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…
Montmorillonite was organically modified with distearyldimethylammonium chloride. This organically modified clay (OMON) and poly (ϵ-caprolactone) (PCL) were solvent-cast blended with chloroform, and the structure and properties of the resulting PCL-clay blends were investigated. From isothermal crystallization experim…
The structure of the $(\sqrt{31}\times \sqrt{31})R\pm9^\circ$ reconstructed phase on sapphire (0001) surface is investigated by means of a simulation based on the energy minimization. The interaction between Al adatoms is described with the semi-empirical many-body Sutton-Chen potential, corrected for the charge trans…
Correlated ab-initio ground-state calculations, using relativistic energy-consistent pseudopotentials, are performed for six II-VI semiconductors. Valence ($ns,np$) correlations are evaluated using the coupled cluster approach with single and double excitations. An incremental scheme is applied based on correlation co…
The free energies of vacancy pair formation and migration in MgO were computed via molecular dynamics using free-energy integrations and a non-empirical ionic model with no adjustable parameters. The intrinsic diffusion constant for MgO was obtained at pressures from 0 to 140 GPa and temperatures from 1000 to 5000 K.…
This book deals with the electron density distribution in molecules and solids as obtained experimentally by X-ray diffraction. It is a comprehensive treatment of the methods involved, and the interpretation of the experimental results in terms of chemical bonding and intermolecular interactions. Inorganic and organic…
We have developed methods for obtaining and characterizing three-dimensional maps of the reciprocal-space distribution of diffuse x-ray scattering from protein crystals, and have used the methods to study the nature of disorder in crystals of Staphylococcal nuclease. Experimentally obtained maps are 99.5% complete in…
The characterization of protein-folding kinetics with increasing chain length under various thermodynamic conditions is addressed using the capillarity picture in which distinct spatial regions of the protein are imagined to be folded or trapped and separated by interfaces. The quantitative capillarity theory is based…
L-Asparaginyl and L-aspartyl residues in proteins are subject to spontaneous degradation reactions that generate isomerized and racemized aspartyl derivatives. Proteins containing L-isoaspartyl and D-aspartyl residues can have altered structures and diminished biological activity. These residues are recognized by a hi…
First principles calculations show that chemisorbed H causes vacancy reconstructions and faceting of all Al low index surfaces. On Al(111) H-decorated vacancies are stable; on H-covered Al(100) vacancies are easily activated thermally. H-covered Al(110) forms a missing row reconstruction with H-decorated vacancies on…
Atomic-force microscopy measurements on KDP ${101}$ faces are presented which show that the terrace width $W$ on vicinal dislocation growth hillocks is nearly independent of supersaturation \ensuremath{\sigma} and Burgers vector $b$, in contradiction to simple Burton-Cabrera-Frank models. An analytical model taking in…
Large-scale integrated fabrication in a H2 containing atmosphere, for example, during the passivation process, can cause serious damage in metal/Pb(Zr,Ti)O3/metal capacitors (i.e., Pt/PZT/Pt capacitors). To reveal the cause of the H2 damage, we investigated the behavior of hysteresis curves and the leakage current of…
We report on quantum molecular dynamics simulations of ${\mathrm{C}}_{28}$ deposition on a semiconducting surface. Our results show that under certain deposition conditions ${\mathrm{C}}_{28}$'s act as building blocks on a nanometer scale to form a thin film of nearly defect-free molecules. The ${\mathrm{C}}_{28}$'s b…
Raman scattering in ${\mathrm{Ge}}_{x}{X}_{1\ensuremath{-}x}$ glasses, $X\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\mathrm{S}$ or Se, reveals that the frequency of ${A}_{1}$ modes of corner-sharing $\mathrm{Ge}({X}_{1/2}{)}_{4}$ tetrahedra displays a discontinuous jump between $x\phantom{\rule{0ex}{0ex}}=\pha…
Raman scattering spectra of single-wall nanotubes with mean radii 0.55, 0.65, and 1.0 nm show size-dependent multiple splittings of the optical phonon peak corresponding to the ${E}_{2g}$ mode in graphite. These splittings constitute the first experimental evidence for the unique feature of nanotubes that they exhibit…
The contribution from the irreversible displacement of non- domain walls to the direct longitudinal piezoelectric coefficient of and ceramics was determined quantitatively by using the Rayleigh law. Effects of the crystal structure and microstructure of the ceramics as well as the external d.c. pressure on the domain…