Materials Literature
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A new family of organic-inorganic hybrid material of alpha-nickel hydroxide formulated as Ni(OH)2-x(An-)x/n-(C6H12N4)y.zH2O (A=Cl-, CH3COO-, SO4(2-), NO3-; x=0.05-0.18, y=0.09-0.11, z=0.36-0.43) with high stability and adjustable interlayer spacing ranging from 7.21 to 15.12 A has been successfully prepared by a simpl…
Colloidal bimetallic nanoparticles of Pt-Ru have been synthesized by sonochemical reduction of Pt(II) and Ru(III) in aqueous solutions. Transmission electron microscope (TEM) images indicate that sequential reduction of the Pt(II) followed by the Ru(III) produces particles with a core shell (Pt@Ru) morphology. In the…
Boron-doped (B-doped) single-walled (8, 0) carbon nanotubes (SWCNTs) are investigated using density functional theory (DFT) calculations as sensor models to detect the presence of cyanides, such as hydrogen cyanide (HCN) and cyanogen chloride (CNCl). Comparing the results of the intrinsic SWCNTs with HCN and CNCl, we…
Bivalve nacre is a brick-wall-patterned biocomposite of aragonite platelets surrounded by organic matter. SEM-electron back scatter diffraction analysis of nacre of the bivalve family Pteriidae reveals that early aragonite crystals grow with their c-axes oriented perpendicular to the growth surface but have their a- a…
We consider the fractional generalizations of equation that defines the medium mass. We prove that the fractional integrals can be used to describe the media with noninteger mass dimensions. Using fractional integrals, we derive the fractional generalization of the Chapman-Kolmogorov equation (Smolukhovski equation).…
Solid-phase microextraction commercial fibers present a few drawbacks such as relatively low recommended operating temperature, instability and swelling in organic solvents, breakage of the fiber, stripping of coatings, and bending of the needle. Some of these problems have been obviated by covalent bonding of the pol…
The influence on calcium carbonate crystallization of a series of biopolymers that contain carboxylic acid or sulfate functional groups was studied using pH and turbidity measurements, optical microscopy, and scanning electron microscopy. Without biopolymer, single calcite (104) rhombohedra were formed. In the presenc…
We use the fractional integrals in order to describe dynamical processes in the fractal media. We consider the "fractional" continuous medium model for the fractal media and derive the fractional generalization of the equations of balance of mass density, momentum density, and internal energy. The fractional generaliz…
Investigations of the optical response of subwavelength structure arrays milled into thin metal films has revealed surprising phenomena including reports of unexpectedly high transmission of light. Many studies have interpreted the optical coupling to the surface in terms of the resonant excitation of surface plasmon…
A simple, physically motivated, scaling hypothesis, which becomes exact in important limits, yields estimates for the ground-state energy of large, composed, systems in terms of the ground-state energy of its building blocks. The concept is illustrated for the electron liquid, and the Hubbard model. By means of this s…
We present the electronic structure of Sr(1-(x+y))La(x+y)Ti(1-x)Cr(x)O3 investigated by high-resolution photoemission spectroscopy. In the vicinity of the Fermi level, it was found that the electronic structure was composed of a Cr 3d local state with the t(2g)3 configuration and a Ti 3d itinerant state. The energy le…
We present a microscopic model for surface-enhanced Raman scattering (SERS) from molecules adsorbed on small noble-metal nanoparticles. In the absence of direct overlap of molecular orbitals and electronic states in the metal, the main enhancement source is the strong electric field of the surface plasmon resonance in…
The spin-transfer torque from a DC spin-polarized current can generate highly-coherent magnetic precession in nanoscale magnetic-multilayer devices. By measuring linewidths of spectra from the resulting resistance oscillations, we argue that the coherence time can be limited at low temperature by thermal deflections a…
One-dimensional ZnO nanostructure arrays such as nanowires, nanonails, and nanotrees, have been synthesized by oxygen assisted thermal evaporation of metallic zinc on a quartz substrate over a large area. Morphological evolution of ZnO nanostructures at different time scales and different positions of the substrates h…
We study an undoped t-J model with electron-phonon interaction using the self-consistent Born approximation (SCBA). By neglecting vertex corrections, the SCBA solves a boson-holon model, where a holon couples to phonons and magnons. Comparison with exact diagonalization results for the t-J model suggests that the SCBA…
An invisibility device should guide light around an object as if nothing were there, regardless where the light comes from. Ideal invisibility devices are impossible due to the wave nature of light. This paper develops a general recipe for the design of media that create perfect invisibility within the accuracy of geo…
The crystal structure of the PbMg$_{1/3}$Ta$_{2/3}$O$_3$ (PMT) relaxor ferroelectric was studied under hydrostatic pressure up to $\sim 7$ GPa by means of powder neutron diffraction. We find a drastic pressure-induced decrease of the lead displacement from the inversion centre which correlates with an increase by $\si…
This Comment corrects two separate errors which previously appeared in the calculation of vibrational mode frequencies of tin spheres embedded in a silica matrix. The first error has to do with the vibrational frequency of a free elastic sphere. The second error has to do with the effect on the vibrational frequencies…
November 2002, "Magister", Supervisors : Dr. H. Bouzar (Tizi-Ouzou, Algeria) with the collaboration of Dr. V. Pierron-Bohnes and Dr. C. Goyhenex (Strasbourg, France). Mouloud Mammeri University, Tizi-Ouzou (Algeria) and Louis Pasteur University, Strasbourg (France).
We study the effects of magnetoelastic coupling on the degenerate ground state of the spin-1/2 antiferromagnetic Heisenberg model for the regular triangular spin cluster. Static displacement of spins spontaneously lifts the degeneracy of the ground state through the distance dependence of exchange coupling, i.e., a sp…