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It has been possible to develop a technique to assess the local porosity in a selected region of interest in a porous medium. This technique also allows quantification of the distribution of the pore volume fraction in varying ranges of pore sizes.

Porous a-Si:H and porous a-Si:C:H thin films and their visible photoluminescence are discussed. Boron-doped p-type a-Si:H samples showed visible photoluminescence and others did not. Discrete defect or impurity levels were evidenced in temperature-dependent luminescence measurements, where there were multiple luminescence peaks. In porous amorphous silicon the luminescence energy does not change with porosity. Crystallinity is not required for light emission to occur.

Near edge x-ray absorption fine structure measurements and optical properties of porous silicon samples with different levels of porosity reveal the features of an Si atomic region. The sample which has the lowest porosity does not exhibit luminescence. Since Si substances with higher values of porosity exhibit luminescence, these samples are subjected to time resolved photoluminescence (PL) measurements. Time resolved PL measurements reveal that the high porosity samples possess large amount of passivating Si-H groups on the surface.

Analysis of pore morphology showed that porous layers formed in the n-type silicon are composed of pores with cross section oriented perpendicular to the (100) plane. (001) planes in the (100) zone define the pore walls with secondary pores propagating from the main pores in the (010) and (001) directions. Pore morphology results from a tunneling mechanism due to a high-field region created by the curvature at the pore front.

A study of silicon dioxide deposited by liquid-phase-deposition method to determine the infrared absorption spectra reveals a new type of variation in the intensity ratio between the side lobe and main peak. The variation depends on the dilution ratio of growth solution and boric acid concentration. Silicon dioxide has a smaller refractive index, and the porosity in its structure is large.

The impact of porosity and pore orientation on the magnetization process of lotus-type porous metals is discussed. The saturation magnetization of these metals is shown to vary linearly with the porosity.

The phenomenon of phase change materials (PCMs) inside high thermal conductivity foams is experimentally studied. An optimal value is required for the foam porosity and pore size such that the effects of both conduction and convection heat transfers are used to have an improved thermal performance for the wax/aluminum foam composite.

The hybrid deposition is performed by plasma enhanced chemical vapor deposition and an appropriate matrix structure is used for studying the effect of the porogen loading on the porosity creating. A porous a-SiOCH film is obtained with an ultralow k value of 2.3 by using the porous a-SiOCH structure and porogen loading.

A method is developed for directly determining the open porosity of porous solids. The method and its error prediction are tested on different samples of the known open porosity.

A study characterized methylsilsequioxane (MSQ) based porous low-k dielectric films by x-ray porosimetry (XRP) to determine their pore size distribution, average density, wall density, and porosity. By varying the porogen content from 1% to 30% by mass, the porosity changes from 12% to 34% by volume, indicating that the base MSQ matrix material contains approximately 10% by volume inherent microporosity.

Ba[Fe.sub.12][O.sub.19] hexaferrite thick films having high hysteresis loop squareness and low ferromagnetic resonance (FMR) linewidths are processed through the use of a screen printing technique coupled with hot-press sintering. The results have shown that the narrow linewidths can be attributed to the reduction in porosity and the improvement in c-axis orientation of crystallites in polycrystalline barium ferrite films.

The Ti[O.sub.2] films with periodic index profiles are fabricated by using a deposition technique known as glancing angle deposition (GLAD) and are characterized. The results have shown how nanoscale porosity engineering using GLAD is a precise technique for fabricating one-dimensionally periodic films with a variety of optical characteristics.

A laser reflection method is developed and tested for analyzing the etching of porous silicon (PS) films. The method enables feedback control of the etching so that PS films with a well-controlled porosity are obtainable.

A laser reflection method is developed and tested for analyzing the etching of porous silicon (PS) films. The method enables feedback control of the etching so that PS films with a well-controlled porosity are obtainable.

A design optimization study that allowed inverse determination of effective parameters was studied. The results are good enough to encourage monitoring porosity changes in medical and industrial applications.

A study of the effect of material properties on the packing of fine particles is presented. The results show that variables such as sliding and rolling friction, Hamaker constant and particle density strongly affect the packing properties such as porosity, mean coordination number and RDF, as well as the forces and torques acting on a particle.

A thermodynamic equation of state (EOS) for thermoelectrons is derived to investigate the thermodynamics variations along isobaric paths. This method has the advantage of being able to model the behavior of porous metals over the full range of applicability of pressure and porosity.

The laser flash technique is adequate for measuring the thermal diffusivity of materials with high porosity and coarse pores by applying the correct models and corrections. The three layer structures formed by two layers of a high diffusivity material attached to both sides of porous specimen gives reliable values of thermal diffusivity for this type of material.

A study was conducted, using a 3omega method, to examine the thermal conductivity of SiO2 thin films prepared using various procedures. The result reveals that the thermal conductivity of the SiO2 thin films correlates closely with their porosity.