The reactivity of disordered, noncrystalline U(IV) species remains poorly characterized despite their prevalence in biostimulated sediments. Because of the lack of crystalline structure, noncrystalline U(IV) may be susceptible to oxidative mobilization under oxic conditions. The present study investigated the mechanism and rate of oxidation of biogenic noncrystalline U(IV) by dissolved oxygen (...

Drawable water-swollen cellulose films were prepared by coagulating in water two different cellulose organic solution systems. The drawability of the waterswollen films was dependent on the rate of coagulation. Transparent films prepared by the slow coagulation showed good drawability and had a maximum draw ratio of 2.0. However, the drawn films maintained the highly noncrystalline state even a...

Experimental X-ray crystallography, NMR (Nuclear Magnetic Resonance) spectroscopy, dual polarization interferometry, etc are indeed very powerful tools to determine the 3-Dimensional structure of a protein (including the membrane protein); theoretical mathematical and physical computational approaches can also allow us to obtain a description of the protein 3D structure at a submicroscopic leve...

We explore the basic physical origins of the noncrystalline and crystalline components of the anisotropic magnetoresistance (AMR) in (Ga,Mn)As. The sign of the noncrystalline AMR is found to be determined by the form of spin-orbit coupling in the host band and by the relative strengths of the nonmagnetic and magnetic contributions to the Mn impurity potential. We develop experimental methods yi...

Oxide thickness and oxidation time data related to thermal oxidation of silicon are interpreted by a model in which the oxygen transport through the noncrystalline oxide has two components: one is the usual random-walk diffusion dependent on thickness and the other one is independent of thickness. The latter one is attributed to transport through structural channels.

Until recently, the reduction of U(VI) to U(IV) during bioremediation was assumed to produce solely the sparingly soluble mineral uraninite, UO2(s). However, results from several laboratories reveal other species of U(IV) characterized by the absence of an EXAFS U–U pair correlation (referred to here as noncrystalline U(IV)). Because it lacks the crystalline structure of uraninite, this species...

The effect of preparation conditions on the structural and optical properties of silicon nanoparticles is investigated. Nanoscale reconstructions, unique to curved nanosurfaces, are presented for silicon nanocrystals and shown to have lower energy and larger optical gaps than bulk-derived structures. We find that high-temperature synthesis processes can produce metastable noncrystalline nanostr...