Materials Literature
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A class of poly(ethylene-co-methacrylic acid) (EMAA) copolymers and ionomers has shown the unique ability to instantaneously self-heal following ballistic puncture. It is noteworthy that the thermomechanical healing process active in these materials appears to be significantly different in capability and mechanism tha…
(4-Biphenylyl)phenyldibenzofulvene is weakly luminescent in the amorphous phase but becomes highly emissive upon crystallization; this unusual crystallization-induced emission enhancement effect allows its emission to be repeatedly switched between dark and bright states by fuming-heating and heating-cooling processes.
Photoluminescence of simple arylbenzenes with ready synthetic accessibility is enhanced by two orders of magnitude through aggregate formation; viscosity and temperature effects indicate that the emission enhancement is due to the restriction of their intramolecular rotations in the solid state.
Significant quantities of highly enriched uranium (HEU)—more than enough to make a Hiroshima bomb—are used annually as neutron target material in Canadian, European, and South African reactors to produce the short-lived fission products used in nuclear medicine. The most important of these fission products is 99Mo, wh…
We study the spin ordering within the three-leg ladders present in the oxyborate Fe3O2BO3 consisting of localized classical spins interacting with conduction electrons (one electron per rung). We also consider the competition with antiferromagnetic superexchange interactions to determine the magnetic phase diagram. Be…
Pairs of reflection electron energy loss spectra recorded at different incident energies are decomposed to give the energy loss distribution in individual inelastic collisions at the surface and in the bulk of the solid. The resulting single scattering loss distributions are fitted to a Drude-Lindhard model for the di…
Multi‐walled carbon nanotubes (MWNTs) were used to prepare natural rubber (NR) nanocomposites. Our first efforts to achieve nanostructures in MWNTs/NR nanocomposites were formed by incorporating carbon nanotubes in a polymer solution and subsequently evaporating the solvent. Using this technique, nanotubes can be disp…
Horizontally surface-stabilized orthoconic antiferroelectric liquid crystals (OAFLCs) provide excellent contrast electrooptic switching. However, in very thin cells the bulk relaxation to the anticlinic state tends to be slow because the synclinic state is upheld by the surfaces. In cells thin enough to accomplish a s…
The authors have prepared heterostructured ZnO∕BiFeO3-PbTiO3 (BFO-PT) composite film and BFO-PT film on Pt∕Ti∕SiO2∕Si substrates by pulsed-laser deposition. The structure and morphologies of the films were characterized by x-ray diffraction (XRD) and scanning electron microscope. XRD results show that both films are p…
A focused ion beam microscope has been used to mill rectangular “picture-frame” shapes from single crystal barium titanate. The lengths of the sides of the picture frames were of the order of 3–5μm, while the side width and thickness dimensions were of the order of 100–500nm. Such aspect ratios meant that each of the…
Aluminum and gallium show some interesting differences in their coordination chemistry. Solid GaH3 is unknown, in contrast to solid AlH3. Ga equivalents of Li3AlH6, Na3AlH6, and other hydrides whose structure contain AlH(3-)6 ions, are unknown. We relate these differences to an instability of the hexacoordinated galli…
We discuss the phase coexistence of polydisperse colloidal suspensions in the presence of adhesion forces. The combined effect of polydispersity and Baxter's sticky-hard-sphere (SHS) potential, describing hard spheres interacting via strong and very short-ranged attractive forces, give rise, within the Percus–Yevick (…
Smectic liquid crystals can be made to form freely suspended films, two-dimensional systems locally quantized in thickness by an integral number of smectic layers, on which islands, circular regions of greater thickness than the surrounding film area, can be generated. In smectic C films, each such island is accompani…
We present ab initio calculations of electron-phonon coupling matrix elements of the totally symmetric high-energy vibrational modes of carbon nanotubes. The matrix elements depend on nanotube family $({n}_{1}\ensuremath{-}{n}_{2})\mathrm{mod}\phantom{\rule{0.2em}{0ex}}3$, chiral angle, and the particular optical tran…
Using Monte Carlo simulations we study reversible end-adsorption of head-to-tail associating polymers on a surface containing adsorption sites. The adsorption energy was considered to be similar to the association energy (10 kT ) leading to the competition between association in the bulk and adsorption. We found that…
Multi‐wall carbon nanotubes were synthesized from sucrose by a pyrolytic technique using mesopourous MCM‐41 silicate templates without transition metal catalysts. The nanotubes were examined in the carbon/silicate composite and after dissolution of the silicate. High‐resolution transmission electron microscopy study o…
In this letter, the authors show by ab initio density functional calculations and experiments that Mn doped semiconducting half-Heusler compound NiTiSn can exhibit room-temperature ferromagnetism. Curie temperatures were calculated by Monte Carlo simulations using calculated Heisenberg exchange parameters in an ab ini…
Poly(3-hydroxybutyrate) (PHB) granule formation in Azotobacter vinelandii was investigated by laser scanning fluorescence microscopy after staining the cells with Nilered and Baclight. Cells that had been starved for a carbon source for > or =3 days were almost free of PHB granules. Formation of visible PHB granules s…
Dielectric spectra measured within 10−3Hz⩽f⩽104Hz in the paraelectric state of Sr0.61Ba0.39Nb2O6 (SBN61) at T>320K reveal a broadened Debye-type relaxation at f≈100Hz and a power-law low-f increase at f<10−1Hz. These anomalies are attributed to the dynamic modes wall segment relaxation and creep of the i…
Bi 1.5 Zn 1.0 Nb 1.5 O 7 ∕ Ba 0.6 Sr 0.4 Ti O 3 ∕ Bi 1.5 Zn 1.0 Nb 1.5 O 7 (BZN/BST/BZN) sandwich films were deposited by radio frequency magnetron sputtering. The relative permittivity and dielectric loss of the sandwich films were measured using planar Pt∕BZN∕BST∕BZN∕Pt∕Ti∕SiO2∕Si capacitor structures. The sandwich…