Materials Literature
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Une structure granulaire est un assemblage de grains dont les tailles sont caractérisées par une distribution donnée. Un échantillon de ce type de structure est souvent modélisé par un rectangle rempli de disques en deux dimensions ou un parallélépipède contenant des boules en trois dimensions. La modélisation géométr…
We have used $^{17}\mathrm{O}$ NMR to probe the magnetic homogeneity in both the paramagnetic and the ferromagnetic states of a high-quality ${\mathrm{Nd}}_{0.5}{\mathrm{Sr}}_{0.5}\mathrm{Mn}{\mathrm{O}}_{3}$ single crystal. The measured broadening of the $^{17}\mathrm{O}$ line reveals that significant two-dimensional…
Abstract Melting behavior, nonisothermal crystallization and isothermal crystallization kinetics of polypropylene (PP) with metallocene‐catalyzed linear low density polyethylene (mLLDPE) were studied by differential scanning calorimetry (DSC). The results show that PP and mLLDPE were partially miscible. The Avrami ana…
Binuclear tantalum clusters were synthesized from Ta(CH 2 Ph) 5 (Ph is phenyl) on the surface of nonporous SiO 2 (Aerosil), and their reactions with H 2, D 2, and ethylene were characterized by time-resolved infrared (IR), extended X-ray absorption fine structure (EXAFS), and X-ray absorption near edge spectroscopies.…
An analytical solution is presented for the stress field around an elastic spherical particle embedded in a finite elastic—plastic metal matrix subjected to hydrostatic tension. The formulation is based on a strain gradient plasticity theory and a unit cell of finite dimensions, and the resulting solution incorporates…
On the basis of the recently developed optimized Rouse-Zimm theory of chain polymers with excluded volume interactions, we calculate the long-time first-order rate constant k(1) for end-to-end cyclization of linear chain polymers. We first find that the optimized Rouse-Zimm theory provides the longest chain relaxation…
In this paper, we have developed a half-space Peierls—Nabarro (HSPN) model to evaluate dislocation mobility on material surface. The free-surface induced size effect on the mobility of an edge dislocation in thin films is investigated by using the model. The thickness of the thin layer between the dislocation and the…
Using a combination of first-principles methods, we have studied the electronic and optical properties, and the magneto-optical Kerr effect in pyrite-structured cobalt sulphide compounds, which are of high technological importance due to their possible half-metallic character. Our study shows that pure $\mathrm{Co}{\m…
Transient photocurrent measurements on evaporated a-Se layers indicate the presence of two sets of discrete traps in the band tail region. The shallower traps, at E V +0.20 eV and E C −0.28 eV, are found to be electrically neutral, while the deeper ones at E V +0.38 eV and E C −0.53 eV are related to the charged negat…
A transparent Yb 3+ :NaY(WO 4 ) 2 single crystal with dimensions of 30 mm (diameter) × 40 mm has been grown by the Czochralski method. The high crystalline quality of the as-grown Yb 3+ :NaY(WO 4 ) 2 crystals was confirmed by high-resolution X-ray diffraction. The effective segregation coefficients of elemental Yb, Na…
Abstract The polymerization of α‐methylstyrene (AMS) catalyzed by Maghnite‐H + (Mag‐H) was investigated. Mag‐H is a montmorillonite sheet silicate clay, exchanged with protons. It was found that the cationic polymerization of AMS is initiated by Mag‐H at ambient temperature in bulk and in solution. The effect of the a…
Abstract The surface modification of montmorillonite clay was carried out through ion‐ exchange reaction using p ‐phenylenediamine as a modifier. This modified clay was employed to prepare aromatic polyamide/organoclay nanocomposite materials. The dispersion behavior of clay was examined in the polyamide matrix. Polya…
Abstract The effect of different thermal treatments on the mechanical and thermal properties of polycarbonate was investigated. The first quenching procedure which involves the quench of the samples from the melt state to different temperatures allowed improving impact strength and elongation at break for a quenching…
The composite materials are of significant importance to the current technological development. Any type of fiber, mechanical properties of which make it exploitable, should be thoroughly studied from the point of view of its potential applications. Our study has been focused on sisal plant fiber that is a local produ…
Abstract The quality, thickness, and chemistry of oxides on metal surfaces play a vital role in a variety of applications. Some of these include adhesion of elastomers to metal surfaces, solar cell efficiency, sealing of electronic packaging, reduction of friction during wet drawing, and degree of biocompatibility of…
PURPOSE: To investigate the utility of inversion recovery with ON-resonant water suppression (IRON) to create positive signal in normal lymph nodes after injection of superparamagnetic nanoparticles. MATERIALS AND METHODS: Experiments were conducted on six rabbits, which received a single bolus injection of 80 mumol F…
At half filling, the electronic structure of graphene can be modeled by a pair of free two-dimensional Dirac fermions. We explicitly demonstrate that in the presence of a geometrically induced gauge field an everywhere-real Kekulé modulation of the hopping matrix elements can correspond to a nonreal Higgs field with n…
The phonons and the crystal structures of the $\ensuremath{\beta}$-pyrochlore superconductors ${\text{KOs}}_{2}{\text{O}}_{6}$ and ${\text{RbOs}}_{2}{\text{O}}_{6}$ are studied on single crystals by using micro-Raman spectroscopy. The symmetry of the modes is determined by polarization dependent measurements for vario…
A thermal-light dual response hyperbranched polymer, poly(ethylene imine)-grafted-cyclohexane carboxylic acid (PEI-CCA), was designed and synthesized by introducing hydrophobic cyclohexyl units to the terminals of hyperbranched poly(ethylene imine) (PEI). Proper amounts of hydrophobic cyclohexyl units endue PEI-CCA wi…
Abstract Nanocomposites of recycled poly(methyl methacrylate) (PMMA) and both natural (Nanomer PGV MMT), and organically modified Nanomer I44P, Nanomer I30P and Cloisite 30B montmorillonites (O‐MMT) were prepared by solution dispersion method with the use of two miscible solvents, followed by melt intercalation proces…