in this paper a new optical channel drop filter (cdf) based on two dimensional (2-d) photonic crystals (phc) with hexagonal shaped structure is proposed and numerically demonstrated by using the finite-difference-time-domain (fdtd) and plane-wave-expansion (pwe) techniques. photonic crystals (phcs) are artificial dielectric nanostructure materials in which a periodic modulation of the material ...

In this design an optical ring resonator are embedded between two Horizontal input and output waveguides which has 4 orbitals around the center of the resonator so that each orbital consists of 8 rods with different size in which radius of larger orbitals rods are bigger than radius of smaller orbitals rods. The analysis of simulation results showed the proposed filter has the transmission effi...

introduction: the accuracy of analyzing functional mri (fmri) data is usually decreases in the presence of noise and artifact sources. a common solution in for analyzing fmri data having high noise is to use suitable preprocessing methods with the aim of data denoising. some effects of preprocessing methods on the parametric methods such as general linear model (glm) have previously been evalua...

here, we propose an add-drop and a channel drop filter based on two-dimensional photonic crystal all circular ring resonators. these structures are made of a square lattice of silicon rods with the refractive index n1=3.464 surrounded by air (with refractive index n2=1). the broadest photonic band gap occurs at the filling ratio of r/a = 0.17. two linear defect w1 waveguides couple to the ring....

Antioxidants are vital substances which possess the ability to protect the body from damage caused by free radical induced oxidative stress. A variety of free radical scavenging antioxidants exist within the body which many of them are derived from dietary sources like fruits, vegetables and teas. In this study the antioxidant activity and radical scavenging activity of methanolic extracts of s...

a cochlear implant is an implanted electronic device used to provide a sensation of hearing to a person who is hard of hearing. the cochlear implant is often referred to as a bionic ear. this paper presents an undecimated wavelet‑based speech coding strategy for cochlear implants, which gives a novel speech processor. the undecimated wavelet packet transform (uwpt) is computed like the wavelet ...

a compact and sharp-rejection ultra-wideband (uwb) microstrip bandpass filter (bpf) is presented. the proposed filter is constructed with multiple-mode resonator (mmr) and split ring resonator (srr). moreover, proposed structure consists of two doublets parallel coupling gaps at each side of a microstrip ring. in comparison with some other filters, this structure shows a significantly wider pas...

introduction:  skin  sparing  is  one  of  the  most  desirable  characteristics  of  high  energy  photon  beams. however, the photons emerging from the target of linacs are contaminated by secondary  electrons  as  a  result  of  their  interactions  with  air,  collimators,  flattening  filter  and  any  other  objects in their path. this phenomenon tends to increase the skin dose received b...