Materials Literature
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Using the Rietveld refinement, we analyze the structural evolution under thermal treatment of silica xerogel samples prepared by the sol–gel method with molar ratio (R) of water to TEOS of R = 5 and R = 11.66. We refine the structure of compounds using the Maud program and we found the unit cell parameters and atomic…
We present a first-principles description of anisotropic materials characterized by having both weak (dispersionlike) and strong covalent bonds, based on the adiabatic-connection fluctuation-dissipation theorem with density functional theory. For hexagonal boron nitride the in-plane and out-of-plane bonding as well as…
Carbon nanotube (CNT) is expected for much more important and broader applications in the future, because of its amazing electrical and mechanical properties. However, today, the prospect is detained by the fact that the growth of CNTs cannot be well controlled. In particular, controlling the chirality of CNTs seems f…
We theoretically analyze the excitation energy transfer between two closely spaced linear molecular J-aggregates, whose excited states are Frenkel excitons. The aggregate with the higher (lower) exciton band edge energy is considered as the donor (acceptor). The celebrated theory of Förster resonance energy transfer (…
In the interaction of PVP with Pt nanoparticles <7 nm in size, charge transfer is from carbonyl groups in PVP to Pt nanoparticles, whereas in the interaction of PVP with bulk Pt or Pt nanoparticles >25 nm in size, charge transfer is from Pt metal to the polymer side chain of PVP. There exists a critical nanoparticle s…
Silver nanodendrites are synthesized by a simple surfactant-free method using a suspension of zinc microparticles as a heterogeneous reducing agent. Structural characterizations suggest the preferential growth along 100 and 111 directions by oriented attachment of silver nanocrystals in the diffusion limit, leading to…
We study the nematic structure of a liquid crystal confined within a plan-parallel cell following the temperature driven isotropic-nematic phase transition quench. The Lebwohl-Lasher lattice model is used. The kinetics of the system is followed via Brownian molecular dynamics, enabling us to reach macroscopic time sca…
The presented study deals with pattern forming phenomena in electrohydrodynamic convection (EHC) under superimposed rectangular wave forms. An effect of re-stabilization is observed experimentally, i.e., with changing of one control parameter of the excitation wave form, the system undergoes transitions from the conve…
${\mathrm{Gd}}_{5}{\mathrm{Si}}_{4}$, ${\mathrm{Gd}}_{5}{\mathrm{Ge}}_{4}$, and ${\mathrm{Gd}}_{5.09}{\mathrm{Ge}}_{2.03}{\mathrm{Si}}_{1.88}$ compounds were studied by electron spin resonance. The arc-melted samples were initially characterized by optical metallography, x-ray diffraction, and static magnetization mea…
A finite element technique for computer simulation of transient electromagnetic fields, eddy currents density and power losses distributions due to negative sequence currents in synchronous generator rotors at various operational conditions is developed. Time-varying electromagnetic field calculation is performed in t…
In several mesophases of bent-core liquid crystals, stable freely suspended filaments can be prepared. In this paper, we report a study of smectic liquid-crystal filaments formed by bent-shaped molecules in different mesophases, focused on a mechanical and structural characterization of the filaments.
The threshold characteristics U c (U ac ), q c (U ac )andq c (U c ), whereU c is the d.c. threshold voltage, U ac is a high-frequency orienting voltage with a frequency above 5000 Hz, and q c is the threshold wave number of the flexoelectric domains of Vistin'-Pikin-Bobylev, excited under the joint action of a d.c. vo…
Holographic gratings of different periods were recorded in the photopolymer by two laser beams with opposite circular polarization and a nematic liquid crystal was brought in contact with them. The anchoring conditions for the nematic were modulated in a similar way and an induced, field controlled replica manifested…
Abstract A liquid crystalline epoxy resin was cured under non‐ and 10T‐magnetic fields, and polydomain and monodomain networks were obtained, respectively. The fracture toughness of these systems was evaluated and it was clarified that the toughness of the magnetic field system showed a higher value. To investigate th…
A study of the optical properties of pure-and some metal ions doped ammonium sulfate crystals (AS) were made. Optical constants of AS crystals were calculated at room temperature. The optical absorption coefficient (α ) was analyzed and interpreted to be in the allowed direct transition. The introduction of Rb+ or Cs+…
ADVERTISEMENT RETURN TO ISSUEPREVNoteEffect of Particle Size, Composition, and Thermal Treatment on the Crystalline Structure of Polycaprolactone NanoparticlesEun Chul Cho, Kilwon Cho, Jong Kun Ahn, Junoh Kim, and Ih-Seop ChangView Author Information Skin Research Institute, Amorepacific Corporation/ R&D Center, 314-1…
Sb2S3 amorphous thin films were prepared by thermal evaporation of corresponding powder on thoroughly cleaned glass substrates held at temperature in the range 300-473 K. X-ray diffraction and atomic force microscopy have been used to order to identify the structure and morphology of surface thin films. The optical co…
Two mesoporous ordered carbon materials (MOCs) have been synthesized from silica templates by using sucrose as the carbon precursor. The textural characterization using Ar, N2, and CO2 adsorption combined with neutron diffraction showed that the two samples exhibit a significant microporous volume close to 0.5 cm3/g a…
Temperature has great impact on the structure and size of the linked crystallites of the conducting topmost layer formed at the surface of a polycarbonate film via the reaction BEDT-TTF+IBr [BEDT-TTF=bis(ethylenedithio)tetrathiafulvalene]. We show that fine temperature control permits formation of a semiconducting top…
The degree of adhesion of protein crystals, heterogeneously nucleated and grown on different supports (e.g. glass plates and plates coated with poly-L-lysine, hexamethyl-disilazane and silicon) is measured directly with a purposely-developed technique. The sticking force crystal/support is determined by means of a fle…