We study the focusing properties of a two dimensional complex square-lattice photonic crystal (PC) comprising air holes immersed in Ge medium. The finite difference time domain (FDTD) method is utilized to calculate the dispersion band diagram and to simulate the image formation incorporating the perfectly matched layer (PML) boundary condition. In contrast to the common square PCs with the sam...

The US has been engaged in irregular warfare (IW) for more than a decade, and faces the prospect of IW for years to come. To prepare for this eventuality and win its current wars, America’s military has modified its doctrine to account for IW. The joint force air component commander (JFACC) for US Central Command (USCENTCOM) has gone even further, and established a non-doctrinal, sub-theater co...

background: the activity concentrations of some radionuclides in soil samples collected from 20 locations in 8 major towns in oyo state, southwestern nigeria have been determined by gamma-ray spectrometry technique. materials and methods: the activity concentrations were determined using high-purity germanium (hpge) detector (canberra industries inc.). the outdoor absorbed dose rates in air at ...

abstract background: bioaerosol is defined as airborne particles such as living organisms include bacteria, fungi and their related metabolites, such as endotoxin. over the recent years, health effects of bioaerosols such as infectious and respiratory diseases, acute toxic effects, allergies and cancer have been considered. the aim of this study was to evaluate the bacterial and fungal concentr...

swelling urban populations and increasing number of industry and especially automobiles in and around cities have resulted in adverse effect on human health. one of the most important things regarding air pollution in these days is that the number of motor vehicles has increased, and the resulting problems of new types of air pollution on large scale need to be emphasized in large cities.the gr...

BACKGROUND Sealants and other building materials sold in the U.S. from 1958 - 1971 were commonly manufactured with polychlorinated biphenyls (PCBs) at percent quantities by weight. Volatilization of PCBs from construction materials has been reported to produce PCB levels in indoor air that exceed health protective guideline values. The discovery of PCBs in indoor air of schools can produce nume...