Materials Literature
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When polyethylene (PE) is deformed to large strains, the stress originates from both the viscous forces associated with the plastic deformation of the crystallites by slip and fragmentation processes and the entropic elastic forces arising from the stretching of the entangled amorphous regions. Relative weights of the…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTRole of l-3,4-Dihydroxyphenylalanine in Mussel Adhesive ProteinsMiaoer Yu, Jungyeon Hwang, and Timothy J. DemingView Author Information Departments of Materials and Chemistry University of California, Santa Barbara Santa Barbara, California 93106 Cite this: J. Am. Chem…
The basic approach bonding in tetrahedral semiconductors elastic properties of semiconductors the dielectric properties of semiconductors semiconductor energy bands electronic properties effects of lattice distortions impurities and defects bonding in ionic crystals elastic properties of ionic crystals dielectric prop…
Banana-shaped compounds form several new smectogenic phases specific to this class. Several two-dimensional phases have been observed, and these can exhibit very complex and beautiful optical textures (see Figure). These phases are reviewed and their structures investigated by not only X-ray diffraction and nuclear ma…
Glycidol represents a latent cyclic AB 2 -type monomer that can be polymerized in a ring-opening multibranching polymerization (ROMBP). Hyperbranched aliphatic polyethers with controlled molecular weights and narrow molecular weight distribution have been prepared via anionic polymerization of glycidol with rapid cati…
The effect of rubber phase content on notched Izod for polystyrene (PS) and polybutadiene (PB) blends compatibilized with PS-PB diblock and PS-PB-PS triblock copolymers has been studied. The effectiveness of various PS-PB-PS triblock copolymers in improving the impact strength of PS/PB blends has been studied. The eff…
Baking (Pb, La)(Zr, Ti)O3 capacitors in a hydrogen atmosphere causes a significant loss of remanent polarization even at 150 °C. The hysteresis variations depend on the polarization states during baking. The hysteresis loop showed voltage shifts when the capacitor was polarized before baking, whereas it became a cramp…
We report the synthesis and characterization of amorphous carbon nitride (CNx) thin films using a direct current magnetron reactive sputter system. Nanoindentation of the CNx films and amorphous carbon films deposited under similar conditions shows the CNx films are extremely elastic, that the addition of nitrogen fun…
The results of studies on the electrochemistry of diamond carried out during the last decade are reviewed. Methods for the preparation, the crystalline structure and the main electrophysical properties of diamond thin films are considered. Depending on the doping conditions, the diamond behaves as a superwide-gap semi…
We have studied isothermal transition kinetics and crystallization mechanisms of the Hoechst Celanese liquid crystal polymer Vectra™ A-950 using a differential scanning calorimetry. This material is a random copolymer with a composition made of 73 mol %/27 mol % of HBA (1,4-dihydroxybenzoic acid)/HNA (2,6-dihydroxynap…
The morphology of melt-crystallized polyethylene is reported. The samples were crystallized for different times at high temperature to produce early stages of spherulitic growth. Morphology studies using transmission electron microscopy showed that the largest proportion of the early objects was monolayers associated…
Continuum concepts are used to evaluate the competition between crack advance and dislocation nucleation at the tip of a crack having a finite tip curvature. The analysis reveals that the favorability of crack propagation versus dislocation emission depends upon the bluntness of the crack tip. One implication is that…
The layered charge-density-wave (CDW) material $2H\ensuremath{-}{\mathrm{NbSe}}_{2}$ was studied by angle-resolved photoelectron spectroscopy. We present the first experimental mapping of the Fermi surface (FS) portions involved in the CDW transition. From this and additional data on the conduction band dispersion nea…
A peculiar bonding feature of $\ensuremath{\alpha}$-rhombohedral boron is found in the electron density distribution of the icosahedral ${\mathrm{B}}_{12}$ cluster. The electron density distribution is obtained by using the maximum entropy method with synchrotron radiation powder data. It clearly shows the characteris…
We have studied lattice dynamic properties of ${\mathrm{SrTiO}}_{3}$ thin films from 5 to 300 K using metal-oxide bilayer Raman scattering. First-order zone-center optical phonons, symmetry forbidden in single crystals, have been observed in the thin films, indicating strain-induced lowering of symmetry. The asymmetri…
The intergrain magnetoresistance (IMR) observed in polycrystalline half-metallic ferromagnets at temperatures below the Curie temperature ${T}_{C}$ was investigated. The systematics of the IMR, as a function of field and temperature for ferromagnetic manganites with varying ${T}_{C}$, shows that the high field magneto…
The symmetry-induced magnetic anisotropy due to monoatomic steps at strained Ni films is determined using results of first - principles relativistic full-potential linearized augmented plane wave (FLAPW) calculations and an analogy with the Néel model. We show that there is a magnetoelastic anisotropy contribution to…
Composites of uniaxially oriented multiwalled carbon nanotubes embedded in polymer matrices were fabricated and investigated by transmission electron microscopy. In strained composite films, buckling was ubiquitously observed in bent nanotubes with large curvatures. By analyses of a large number of bent nanotubes, the…
Abstract: Carbohydrate researchers may think it is reasonable to believe that the synthesis and structure of a crystalline b-1,4 glucan would be quite straightforward; however, this is not the case. The pitfalls and detours of research have been counterbalanced by exciting new discoveries in cellulose structure, biosy…
DFT calculations have been carried out on the titanium carbide clusters Ti 3 C 8, Ti 4 C 8, Ti 6 C 13, and Ti 7 C 13 and their anions, in relation with the recent experimental and theoretical report by L.-S. Wang and his group on those clusters (Wang, L.-S.; Wang, X.-B.; Wu, H.; Cheng, H. J. Am. Chem. Soc . 1998, 120,…