Microstructure and Mechanical Properties of the in situ Β-Si 3 N 4 /Α′-SiAlON Composite

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65911/1/j.1151-2916.1994.tb04604.x.pd

Cubic-to-Tetragonal ( t ') Transformation in Zirconia-Containing Systems

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66338/1/j.1151-2916.1992.tb05546.x.pd

Dynamic polarizability of rotating particles in electrorheological fluids

A rotating particle in electrorheological (ER) fluid leads to a displacement of its polarization charges on the surface which relax towards the external applied field ${\bf E}_0$, resulting in a steady-state polarization at an angle with respect to ${\bf E}_0$. This dynamic effect has shown to affect the ER fluids properties dramatically. In this paper, we develop a dynamic effective medium theory (EMT) for a system containing rotating particles of finite volume fraction. This is a generalization of established EMT to account for the interactions between many rotating particles. While the theory is valid for three dimensions, the results in a special two dimensional configuration show that the system exhibits an off-diagonal polarization response, in addition to a diagonal polarization response, which resembles the classic Hall effect. The diagonal response monotonically decreases with an increasing rotational speed, whereas the off-diagonal response exhibits a maximum at a reduced rotational angular velocity $\omega_0$ comparing to the case of isolated rotating particles. This implies a way of measurement on the interacting relaxation time. The dependencies of the diagonal and off-diagonal responses on various factors, such as $\omega_0$, the volume fraction, and the dielectric contrast, are discussed.Comment: 6 pages, 4 figures, accepted to J. Phys. Chem.

MÖSSBAUER EMISSION SPECTRA OF 119mSnCl2 ADDUCTS WITH SOME OXYGEN AND NITROGEN COMPOUNDS

Des expériences de source Mössbauer ont été réalisées sur le système 119mSnCl2 additionné de composés contenant de l'oxygène ou de l'azote. Les effets chimiques de la réaction nucléaire sont l'apparition d'une faible proportion de l'espèce aliovalente oxydée Sn4+ losque le ligand ajouté est l'eau ou l'aniline; cette proportion devient très importante avec le diméthyl sulfoxyde, le diphényle sulfoxyde, oxyde de pyridine ou les oxydes de picoline.The Mössbauer source experiments of 119mSnCl2 adducts with some oxygen and nitrogen containing compounds were carried out. For the chemical after-effects a small portion of the oxidized alliovalent species of Sn4+ was observed in the spectra of the adducts with the ligands such as water and aniline, whereas a very large portion of the aliovalent charge state was observed in the spectra of the adducts with dimethyl sulfoxide, diphenyl sulfoxide, pyridine N-oxide, and picoline N-oxides