Materials Literature
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The concept of carrier pocket engineering is applied to strained Si/Ge superlattices to obtain a large thermoelectric figure of merit ZT. In this system, the effect of the lattice strain at the Si/Ge interfaces provides another degree of freedom to control the conduction band structure of the superlattice. We explore…
The observation of localized stationary structures, coined oscillons, in granular media has evoked much interest. By parametric excitation of clay suspensions, we demonstrate a hysteretic transition to oscillon-type states in a nongranular medium. When the symmetry of up-down $\mathrm{reflection}+\mathrm{time}$ transl…
We investigate the disordering of an initially phase-segregated binary alloy, due to a highly mobile defect which couples to an electric or gravitational field. Using both mean-field and Monte Carlo methods, we show that the late stages of this process exhibit dynamic scaling, characterized by a set of exponents and s…
We have shown that in narrow 2D semiconductor channels the D'yakonov-Perel' spin relaxation rate is strongly reduced. This relaxation slowdown appears in special waveguide diffusion modes which determine the propagation of spin density in long channels. Experiments are suggested to detect the theoretically predicted e…
We have used Raman spectroscopy to study indium nitride thin films grown by molecular beam epitaxy on (111) silicon substrates at temperatures between 450 and 550 C. The Raman spectra show well defined peaks at 443, 475, 491, and 591 cm{-1}, which correspond to the A_1(TO), E_1(TO), E_2^{high}, and A_1(LO) phonons of…
The atomic structure of icosahedral ${\mathrm{B}}_{4}\mathrm{C}$ boron carbide is determined by comparing existing infrared absorption and Raman diffusion measurements with the predictions of accurate ab initio lattice-dynamical calculations performed for different structural models, a task presently beyond x-ray and…
We present a quantitative description of the thermodynamics in a supercooled binary Lennard-Jones liquid via the evaluation of the degeneracy of the inherent structures, i.e., of the number of potential energy basins in configuration space. We find that the contribution of the inherent structures to the free energy of…
Poly(2-hydroxyethylmethacrylate) (PHEMA)-based microspheres (150–200 µm in diameter) were produced by a modified suspension polymerization of different type of comonomers—namely, acrylic acid, dimethylaminoethyl-methacrylate, and methylmethacrylate. These microspheres were activated with cyanogen bromide (CNBr) at pH…
An ultra-high molecular weight polyethylene (UHMW-PE) fiber was prepared by gel spinning using general kerosene as the solvent and gasoline as the extraction solvent. The process of the phase separation of gel as-spun, spun under various spinning conditions, was investigated. Its extracting and drying process were als…
Binary blends of acrylonitrile-co-butadiene rubber and ethylene propylene diene monomer rubber are immiscible. However, they can be made compatible by addition of a third elastomer viz., chlorinated polyethylene or chlorosulphonated polyethylene in small concentrations. Various sophisticated analytical techniques, e.g…
A number of polyurethane anionomers based on isophorone diisocyanate, polytetrahydrofuran, and cyclohexane dimethanol were prepared as aqueous dispersions. The dispersions were stabilized by the use of an internal emulsifier. The principal ionic moiety used was dimethylol propanoic acid, but dimethylol butanoic acid a…
The aim of this work within the framework of mechanical recycling of polymers is upgrading recycled engineering plastics by means of a blending technique. Four different plastics from dismantled Volvo cars have been investigated. They are poly(acrylonitrile-butadiene-styrene) (ABS) and ABS-polycarbonate (ABS/PC) as ma…
Structural changes proceeding in composites under the effect of various mechanical deformations (stretching, compression, shear, etc.) affect the structure of an electrical conducting system. Mechanical stresses, induced by deformation of composite materials during deformation, affect both the molecular and supermolec…
The miscibility of blends of bisphenol-A polycarbonate (BAPC) and tetramethyl bisphenol-A polycarbonate (TMPC) with copolymers of poly(styrene-co-4-hydroxystyrene) (PSHS) was studied in this work. It has been demonstrated that BAPC is miscible with PSHS over a region of approximately 45–75 mol % hydroxyl groups in the…
In the present article, a series of commercial-grade polypropylenes (PP) filled with different contents of short basalt fibers were studied. This composite material presented deterioration of both mechanical characteristics, for example, stress and strain at yield with increasing of the fiber content. On the other han…
Silver halide particles were synthesized in a water-in-oil microemulsion consisting of AOT (sodium bis-2ethylhexylsulfosuccinate)/ n -heptane/water. Different molecules of thiacyanines were adsorbed on these particles. These molecules can be adsorbed on the particles by two main sites of adsorption: either by an inter…
Using the continental-scale collections of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program, we examined selected members of the family Gomphonemataceae to expand the current state of knowledge of diatom taxonomy, morphology, and distribution. Ten taxa in the genera Gomphonema, Gomphoneis…
The ground-state properties of the tetranuclear Ni 2+ cluster [Ni 4 (H 2 O) 2 (PW 9 O 34 ) 2 ] 10 - were investigated by combining magnetic susceptibility and magnetization measurements with a detailed inelastic neutron scattering (INS) study on a fully deuterated sample of K 6 Na 4 [Ni 4 (H 2 O) 2 (PW 9 O 34 ) 2 ]·24…
The ground-state properties of the tetranuclear Co 2+ cluster [Co 4 (H 2 O) 2 (PW 9 O 34 ) 2 ] 10 - were investigated by combining specific heat, magnetic susceptibility, and magnetization measurements with a detailed inelastic neutron scattering (INS) study on a fully deuterated sample of K 10 [Co 4 (H 2 O) 2 (PW 9 O…
Powders of CdSe nanoparticles were prepared by a pulsed sonoelectrochemical technique. The crystal size could be varied from X-ray amorphous up to 9 nm (sphalerite phase) by controlling the various electrodeposition and sonic parameters. The mechanisms for the effects of the various parameters on particle size are dis…