An optimized graded-refractive-index (GRIN) antireflection (AR) coating with broadband and omnidirectional characteristics--as desired for solar cell applications--designed by a genetic algorithm is presented. The optimized three-layer GRIN AR coating consists of a dense TiO2 and two nanoporous SiO2 layers fabricated using oblique-angle deposition. The normal incidence reflectance of the three-...

 In this research, a numerical modeling was utilized to calculate the stresses caused during thermal cycling in a functionally graded thermal barrier coating (FG - TBC). The temperature – dependent material response of this protective material was taken into account and the effects of thermal cycle and interface morphology of the ceramic / metallic layer in functionally graded coating system wa...

Reducing unwanted reflections through impedance matching, called anti-reflection, has long been an important challenge in optics and electrical engineering. Beyond trial and error optimization, however, a systematic way to realize anti-reflection is still absent. Here, we report the discovery of an analytic solution to this long standing problem. For electromagnetic waves, we find the graded pe...

background: titanium (ti) implants are commonly coated with hydroxyapatite (ha). however, ha has some disadvantages such as brittleness, low tensile strength and fracture toughness. it is desirable to combine the excellent mechanical properties of zro2 and the chemical inertness of al2o3 with respect to the purpose of this project which was coating ti implants with ha-zro2-al2o3 to modify the s...

and light microscopy were used to identify the changes after the heat-treatment. Microhardness and indentation modulus values were also investigated to analyse the changes in the mechanical properties after the heat-treatment. Results of this investigation indicated that the residual stress gradient within the coating material decreases after the heat-treatment, and the stress field in the subs...

Purely elastic, partially and fully plastic stress states in a thick-walled spherical pressure vessel with an inner functionally graded material (FG) coating subjected to internal and external pressures are developed analytically in this paper. The modulus of elasticity and the uniaxial yield limit of the FG coating layer are considered to vary nonlinearly through the thickness. Using Tresca’s ...

This paper presents new exact 3-D (three-dimensional) elasticity closed-form solutions for out-of-plane free vibration of thick rectangular single layered FG (functionally graded) plates and thick rectangular homogeneous plate coated by a functionally graded layer with simply supported boundary conditions. It is assumed that the plate is on a Winkler-Pasternak elastic foundation and elasticity ...

The optical response of graded index spherical particles is studied using an effective medium approach, where the homogenization of the graded particle is achieved by using a static effective dielectric function available in the literature. Full wave calculation using the standard Mie theory for this "homogenized system" shows that for a plasmonic particle, such an approximation can lead to hig...