sol-gel derived sulfur modified and pure zno nanorod were prepared using zinc chloride and thiocarbamide as raw materials. prepared nanorods were characterized by means of x-ray diffraction (xrd), thermogravimetry- differential scanning calorimetry (tg–dsc), uv- vis absorption spectroscopy, brunauer emmett teller (bet) specific surface area and barrett joyner halenda (bjh) pore size distributio...

The angular distribution of photoelectrons predicted for elliptically polarized light is shown to be the same as that predicted for partially polarized light having incoherent perpendicular electric field components equal to the electric field components along the major and minor axes of the ellipse. Increasing use by atomic experimenters of synchrotron radiation, which is known to be elliptica...

Real world surfaces such as tree bark, moss, sponge, and fur often have complicated geometry that leads to effects such as self-shadowing, masking, specularity, and interreflection as the lighting or viewpoint in a scene changes. We use image based techniques to analyze and represent bidirectional texture functions, or BTFs, with correct geometric and lighting effects. A basis for the apparent ...

The bi-directional reflectance distribution function (BRDF) describes the angular distribution of reflectance for any angle of light incident on a surface. It is a crucial parameter for modeling the light field near the benthic surface, and is important for understanding the remote sensing signal from shallow waters. We have been making measurements of this parameter for varied benthic surfaces...

The full-spectrum k-distribution (FSK) approach has become a promising method for radiative heat transfer calculations in strongly nongray participating media, due to its ability to achieve high accuracy at a tiny fraction of the line-by-line (LBL) computational cost. However, inhomogeneities in temperature, total pressure, and component mole fractions severely challenge the accuracy of the FSK...

Recent research in bidirectional importance sampling has focused primarily on structured illumination sources such as distant environment maps, while unstructured illumination has received little attention. In this paper, we present a method for bidirectional importance sampling of unstructured illumination, allowing us to use the same method for sampling both distant as well as local/indirect ...

We consider the flatland or 2D properties of the light field generated when a homogeneous convex curved surface reflects a distant illumination field. Besides being of considerable theoretical interest, this problem has applications in computer vision and graphics—for instance, in determining lighting and bidirectional reflectance distribution functions (BRDFs), in rendering environment maps, a...

A deterministic simulation model for the calculation of sojourn time statistics is proposed. The model is designed for urban cells taking into account city movement in street pattern, traffic lights and crossings. Sojourn time and remaining sojourn time are assumed to be random variables that follow a gamma distribution. The parameters of gamma are found for several possible parameter values us...

This paper presents a practical model for computing the subsurface BRDF of materials composed of a homogeneous semi-infinite layer and a thin painted layer on the top. Solution of light propagation inside a scattering/absorbing medium is expensive. We propose a fast and exact subsurface BRDF computation model using the Ambartsumian’s integral equation for the bottom layer and using invariant im...

W e address a n open and hitherto neglected problem i n computer vision, how to reconstruct the geometry of objects with arbitrary and possibly anisotropic bidirectional reflectance distribution functions (BRDFs) . Present reconstruction techniques, whether stereo vision, structure f rom motion, laser range finding, etc. make explicit or implicit assumptions about the B R D F . Here, we introdu...