Materials Literature
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The mesoscopic concept is a way to deal with complex materials with an internal structure within continuum mechanics. It consists of extending the domain of the balance equations by mesoscopic variables and of introducing a local distribution function of these variables as a statistical element. In our case microcrack…
Experimental results are reported for the bulk motion induced in a bed of granular matter contained in a cylindrical pan with a flat bottom subjected to simultaneous vertical and horizontal vibrations. The motion in space of the moving pan is quantified. A number of distinct bulk dynamical modes are observed in which…
We studied the magnetization as a function of temperature and magnetic field in the compounds ${\mathrm{Nd}}_{0.5}{\mathrm{Sr}}_{0.5}{\mathrm{MnO}}_{3},$ ${\mathrm{Nd}}_{0.5}{\mathrm{Ca}}_{0.5}{\mathrm{MnO}}_{3},$ ${\mathrm{Sm}}_{0.5}{\mathrm{Ca}}_{0.5}{\mathrm{MnO}}_{3},$ ${\mathrm{Dy}}_{0.5}{\mathrm{Ca}}_{0.5}{\math…
We report on the use of the polarized $^3$He gas filter and neutron resonant enhancement techniques for the measurement of spin-polarized diffuse neutron scattering due to ferromagnetic domains. A CoO/Co exchange biased bilayer was grown on a Ti/Cu/$Al_2O_3$ neutron resonator template. The system is cooled in an appli…
We consider fractures in a stratified composite material with solid layers separated by thin slices of extremely soft matter. Viscoelastic effects associated with the soft layers are taken into account via the simplest model for weakly cross-linked polymers. We find that certain small cracks running along layers take…
Shape memory alloy (SMA) has great potential for microminiature actuators. The feasibility is discussed, and theoretical estimates based on scale effect are presented. Control schemes for microminiature SMA servoactuators are discussed, and a control scheme is proposed. Combined with electric resistance feedback and p…
A new method for the growth of high-quality ZnO nanoparticles is presented here; it is a novel, low-cost, and easy operation. This approach, using solid-state heat decomposition at low temperature, allows one to produce ZnO nanoparticles with relatively high dispersivity. The optical properties of the ZnO nanoparticle…
Gold nanoparticles capped by an unsymmetrical azobenzene disulfide, 4-hexyl-4‘-(12-(dodecyldithio)dodecyloxy)azobenzene (C6AzSSC12), were synthesized in order to investigate the efficiency of azobenzene photoisomerization on colloidal gold surfaces. The nanoparticles were synthesized by a two-step method to avoid the…
An optically homogeneous solution/dispersion of single-wall carbon nanotubes (SWNTs) in oleum has been used to form isotropic films exhibiting fibrillar morphology. Tensile modulus, strength, and strain to failure of the film are 8 GPa, 30 MPa, and 0.5%, respectively. The electrical conductivity in the plane of the fi…
The field of electronics using single-molecule components has recently received much attention as a possible new design concept for the continued miniturisation of electronics. Molecular wires are the conceptually simplest components of such electronic systems and several different compound types have been used to pro…
The mechanisms of dislocation intersection and strain hardening in fcc crystals are examined with emphasis on the process of junction formation and destruction. Large-scale 3D simulations of dislocation dynamics were performed yielding access for the first time to statistically averaged quantities. These simulations p…
A simple control for a permanent motor drive is described which provides a wide speed range without the use of a shaft sensor. Two line-to-line voltages and two stator currents are sensed and processed in analog form to produce the stator flux linkage space vector. The angle of this vector is then used in a microcontr…
Thermogravimetric analysis (TGA) is investigated for determination of the OH surface density (OH/nm 2 ) and carbon content of silica and titania powders made by flame aerosol and sol−gel processes. It is shown that it is possible to distinguish between physically adsorbed and chemically bound water and to rapidly dete…
The use of HF-EPR to determine large zero-field splittings in distorted octahedral, high-spin d5 ions is demonstrated with two Mn(II) coordination polymers, giving detail on both electronic and geometric structure.
Long-distance triplet state diffusion in a TiO2/palladium-porphyrin bilayer (see Figure) results in efficient photo-induced charge separation. The larger efficiency for the palladium porphyrin compared with the metal-free or zinc derivatives is attributed to the strong spin–orbit coupling in the former, resulting in s…
The microscopic dynamics in liquid gallium at melting has been studied by inelastic x-ray scattering. We demonstrate the existence of acousticlike modes up to wave vectors above one-half of the first maximum of the static structure factor, at variance with earlier results from inelastic neutron scattering [F. J. Berme…
Computer simulations are used to understand the molecular basis of the rheology changes in polymer melts when loaded with platelet filler particles, specifically when the polymer and nanofiller interact attractively. With decreasing temperature, there is increasing aggregation between chains and filler and an increase…
Abstract The solubility and diffusivity of ethylene in semicrystalline polyethylene were experimentally measured using a magnetic suspension microbalance. The sorption measurements were carried out at temperatures up to 80°C and pressures up to 66 atm. The experimentally measured solubilities were found to decrease wi…
The plane-wave pseudopotential method is used to calculate the high energy exciton states of large CdSe quantum rods, including spin−orbital coupling and screened electron−hole Coulomb interaction. Theoretical ground exciton energies of colloidal CdSe quanutm rods and wires are in good agreement with recent experiment…
A novel catalytic reaction using a trace of organic amine as the catalyst enables hydrolysis of the silicon–hydrogen groups on the fresh prepared porous silicon (PS), generating the hydroxyl-terminated surfaces without extensive oxidation of the Si–Si backbonds. The reactivity of the hydroxyl-terminated surfaces with…