zno thin films with preferred orientation along the (002) plane were prepared onto the glass substrates by the sol-gel spin coating method for different post- annealing temperatures. the xrd study confirms that the thin films grown by this method have good crystalline hexagonal wurtzite structure. the optical band gap of the samples was determined from uv-visible spectra. it is found that the s...

Witten has presented an argument for the vanishing of the cosmological constant in 2 + 1 dimensions. This argument is crucially tied to the specific properties of (2 + 1)-dimensional gravity. We argue that this reasoning can be deconstructed to 3 + 1 dimensions under certain conditions. Our observation is also tied to a possibility that there exists a well-defined UV completion of (3 + 1)-dimen...

I discuss recent progress in the calculation of two-loop QCD corrections in the eikonal approximation. I present specific results for the UV structure of the corrections. Presented at DPF2002, Williamsburg, Virginia, May 24-28, 2002

background : the main objective of this research was to study photocatalytic oxidation of phenol in aquatic solutions by using of uv, tio 2 and the combination of them. phenol compounds are widely used in industries and other daily life. highly toxicity and carcinogenicity of these compounds can causal considerable adverse effects on the aquatic ecosystems and human health. methods : the study ...