The adsorption of N2 molecules inside C24Cs has been studied in detail as a function of temperature and pressure using n-diffraction and nuclear resonance photon scattering (NRPS). Large differences were observed between samples derived from highly oriented pyrolytic graphite and those prepared from graphite powder. The tilt angle of the N2 molecular axis was determined by using NRPS and found to lay nearly parallel to the graphite planes. The amount of adsorbed N2 increased with decreasing temperatures, reaching saturation composition C24Cs(N2)1.5 at approximately 100 K with an initial N2 pressure of 2 bar. At higher pressure, 9 bar, two new phases were formed: a second stage C32Cs(N2)2.1 and a first stage C16Cs(N2)1.8 at T < 170 K and are discussed in detail.

The structures of ordered and disordered β-eucryptite have been determined from Rietveld analysis of powder synchrotron x-ray and neutron diffraction data over a temperature range of 20 to 873 K. On heating, both materials show an expansion within the (001) plane and a contraction along the c axis. However, the anisotropic character of the thermal behavior of ordered β-eucryptite is much more pronounced than that of the disordered compound; the linear expansion coefficients of the ordered and disordered phases are αa = 7.26 × 10−6 K−1; αc = −16.35 × 10−6 K−1, and αa = 5.98 × 10−6 K−1; αc = −3.82 × 10−6 K−1, respectively. The thermal behavior of β-eucryptite can be attributed to three interdependent processes that all cause an increase in a but a decrease in c with increasing temperature: (i) Si/Al tetrahedral deformation, (ii) Li positional disordering, and (iii) tetrahedral tilting. Because disordered β-eucryptite does not exhibit tetrahedral tilting, the absolute values of its axial thermal coefficients are smaller than those for the ordered sample. At low temperatures, both ordered and disordered β-eucryptite exhibit a continuous expansion parallel to the c axis with decreasing temperature, whereas a remains approximately unchanged. Our difference Fourier synthesis reveals localization of Li ions below room temperature, and we suggest that repulsion between Li and Al/Si inhibits contraction along the a axes.

The surface of carbon spheres was studied by using field-emission scanning electron microscopy and scanning tunneling microscopy paying particular attention to the effects of atmosphere during carbonization and of subsequent oxidation on shape and size of the entrance of micropores. Commercial spheres of glasslike carbon prepared by carbonization of phenol resin spheres in either N2 or CO2 atmosphere were subjected to the oxidation by immersing into nitric acid and then heating in air at 400 °C. The size distribution of pore entrance at nanoscopic scale was determined from scanning tunneling microscope images. Carbon spheres prepared in CO2 atmosphere had predominantly ultramicropores, but those prepared in N2 had a very low porosity. The behavior during the oxidation process in air was found to be quite different on these two carbon spheres; spheres carbonized in N2 were oxidized heterogeneously, but those in CO2 showed homogeneous oxidation, giving a high density of ultramicropores.

Thin films possessing microstructure composed of isolated vertical pillars were deposited by glancing angle deposition (GLAD) without the need for subsequent etch processing. The GLAD technique uses substrate rotation and oblique angle flux incidence to deposit a porous columnar thin film with engineered microstructures. Thin films with a pillar microstructure were fabricated from a variety of metals, metal oxides and fluorides, and semiconductors. The rate and incident angle of vapor flux, as well as the substrate rotation speed during deposition, were found to critically affect pillar microstructure. Thin films with pillar diameters and densities as low as 30 nm and 3 pillars per μm2, respectively, were deposited. The low stress, high surface area, and porous nature of these films suggests use of pillar microstructure films in optical, chemical, biological, mechanical, magnetic, and electrical applications.

When polycrystalline films form by nucleation, growth, impingement, and coalescence of islands on a substrate surface, the grain size at impingement depends on the relative magnitudes of the nucleation rate, the growth rate, and the dimension of the zone from which adatoms diffuse to a growing island. A simple description of the interdependence of these parameters is developed. It is used to discuss the dependence of the grain-size-at-impingement and the intrinsic stress resulting from coalescence on the deposition rate and the substrate temperature, and to discuss how these might affect texture evolution during film growth.

Shock compression experiments on powder mixtures of niobium metal and quartz were conducted for the pressure range of 30–40 GPa by a 25-mm single-stage propellant gun. Chemical reaction occurred above 35 GPa, and products were found to be mainly so-called “Cu3Au-type” Nb3Si, which contained a small amount of oxygen. Microtextures of the specimen were examined by scanning and transmission electron microscopy. A field-emission transmission electron microscope was used for energy-dispersive x-ray analysis of microtextures in small particles found in the SiO2 matrix, and various species with different Nb/Si ratio and oxygen content were shown to be produced through the nonequilibrium process of shock compression.