Materials Literature
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We observed high N contents inside BN fullerenelike multilayered nanocages (ca. 30–100 nm) formed by reacting CNx nanotubes (x⩽0.1) and B2O3 in a N2 atmosphere at 1985–2113 K. High-resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy, energy dispersion x-ray spectroscopy, electron dif…
The La0.7Ca0.3−xBaxMnO3 (x=0; 0.03; 0.06…0.3) and La0.7Ca0.3−xSrxMnO3 (x=0.105, 0.12, 0.135, 0.15, 0.165, and 0.18) lanthanum manganites were synthesized and studied. The Curie temperature TC of Ba range showed a sharp change near the concentration structural orthorhombic–rhombohedral phase transition. The TC values f…
Abstract Hydroxy‐terminated polybutadiene (HTPB) prepolymer prepared by free‐radical mechanism at Chemical Engineering Complex, Vikram Sarabhai Space Center, Thiruvananthapuram was reacted with toluene diisocyanate (TDI), a curative at varying stoichiometric ratios ( r = [NCO]/ [OH]) equal to 0.7, 0.8, 0.9, 1.0, and 1…
The fringe-field switching (FFS) mode is known to exhibit both a wide viewing angle and high transmittance, owing to the approximated in-plane rotation of the liquid crystal (LC) director. However, in the bright state, the device shows bluish and yellowish color parallel and perpendicular to the LC director at off-nor…
Electron magnetic resonance (EMR) spectra were measured on different La1−xSrxMnO3 manganites at the interval 100⩽T⩽420 K for studying an influence of the synthesis conditions on the magnetic homogeneity of the sample. The micron-sized crushed crystals La0.833Sr0.126MnO3 and La0.7Sr0.3MnO3 grown by fused-salt electroly…
Recently, the giant magnetoimpedance (GMI) effect found in amorphous wires has been noticed as a method for sensing a magnetic field. The GMI sensor was applied to nondestructive evaluation of microstructural changes for reactor pressure vessel steels passing through the refining process. They were measured by using a…
In this work the magnetic properties of magnetite powders doped with Co and Ni are investigated as a function of dopant concentration. Two sets of Fe3−xTxO4 powders with T=Co and Ni, x=0–1 were prepared using a hydrothermal method, with particle sizes of about 1 μm. The Mössbauer measurements revealed that both Co2+ a…
Electronic structure of NdNiO3 and YNiO3 are calculated by using LSDA+U method with rotational invariance. No orbital order on Ni sites is observed in both systems but different charge orderings. In a small distorting system NdNiO3, all Ni ions are trivalent and oxygen sites have a particular ordering, both in charge…
Binding of protons and metal ions to dendrimers is investigated using a multishell model, in which concentric binding sites are approximated by continuous and uniformly charged shells. The electrostatic interactions among the shells are assumed to be the sole source of site-to-site interactions, and an analytical form…
A technique to perform nanofatigue experiments was developed. This technique utilizes a depth-sensing nanoindenter with harmonic force. The nanofatigue behavior of 20 nm thick amorphous carbon coatings was studied. The contact stiffness was monitored continuously throughout the test. The abrupt decrease in the contact…
We report a systematic study of ferromagnetic resonance (FMR) on thin films of the ferromagnetic semiconductor GaMnAs grown by low temperature molecular beam epitaxy. Pronounced shifts of the FMR line are observed towards fields above and below the g=2.00 resonance position for the magnetic field orientations perpendi…
As a model system for solid polymer electrolytes thin polyethylene oxide (PEO) films (0.6–30 μm) are prepared as Al–PEO–Al and as Al–PEO–Si structures with blocking electrodes. Dielectric measurements (capacitance and loss angle) are carried out in a frequency range of 3 mHz⩽f⩽1 MHz in atmospheres of different relativ…
Dynamic Monte-Carlo simulations of ionic space charge relaxations are carried out using a three-dimensional model for thermally activated ion hopping in a multiwell energy structure. In this model a solid polymer electrolyte is embedded between two ideal blocking electrodes. The polymer is subdivided into 100×100×100…
The intensive milling technique has been used to produce nanocrystalline isotropic PrFeB-based powders. Highly coercive powders were obtained using the base composition R16T76B8 (R: rare earth, T: transition metal) with Dy and Zr additions achieving a high value of μ0Hc=2.66 T for Pr15Dy1Fe75.9B8Zr0.1. The influence o…
Recent research into the development of magnetic refrigeration (MR) operating at room temperature has shown that it can provide a reliable, energy-efficient cooling system. To enhance the cooling power of the magnetic refrigerator, it is required to use a magnetic refrigerant material with large magnetocaloric effect…
The substitution at the Mn site of various transitional metal elements dramatically modifies the magnetic and electronic properties of the La0.7Pb0.3Mn0.8Me0.2O3 (Me=Ni, Co, and Fe) manganites. The powder x-ray diffraction pattern shows a single-phase rhombohedral distorted perovskite structure with space group R3̄c (…
Microstructures of bamboo-like multiwalled carbon nanotubes prepared by pyrolysis of Ni-phthalocyanine are studied by high-resolution transmission electron microscopy. The intershell spacings of graphitic shells in these nanotubes are estimated. From pristine nanotubes with a tube diameter of 40–260 nm, the spacing va…
The hydrodynamic coarsening of microphase separation in two-dimensional diblock copolymers is studied using numerical simulations. Results for symmetric and asymmetric block copolymers are compared. In contrast to the formation of the hexagonal phase where hydrodynamic flow appears not to be effective in enhancing dom…
Mixed sodium–rubidium borate glasses with compositions 0.2[XNa2O·(1-X)Rb2O]·0.8B2O3 (X = 1.0; 0.8; 0.6; 0.4; 0.2; 0.0) were prepared from alkali-metal carbonates and diboron trioxide. The density ρ and the molar volume Vmol of the prepared glasses vary almost linearly with composition whereas the glass-transition temp…
Using x-ray submicrobeam, we spatially mapped the strain in epitaxial La1−xSrxMnO3 films grown on SrTiO3(001) bicrystal substrates. Our results show that there is an elastic strain gradient at the artificial grain boundary, which decays over a length scale of ∼1 μm. The tensile strain at the interior of the grain—due…