In this study, polymerization method with polyethyleneimine, followed by hot-forging process was used to synthesize bulk textured Bi 2 Sr 2 Ca 1-x Na x Cu 2 O y (x=0.0, 0.05, 0.075 0.1, and 0.15) ceramics. Magnetoresistance performance of samples was studied by change of flux pinning mechanism. The effect of Na-substitution on the magnetoresistance, flux pinning energy, irreversibility field, upper critical magnetic field and coherence length was evaluated in the framework of Thermally Activated Flux Flow (TAFF) model. A resistivity transition broadening under various magnetic fields (0-5 T) was analyzed. By using the resistivity data, the upper critical field and the coherence length at T=0 K were deduced. For H c, H C2 (0) and (0) values were calculated as 31

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Current studies combined optics and photonics provide the most promising materials for potential technological and industrial applications, because of their exciting optical and electronic properties. Metals show a lot of optical phenomena associated with their rich dispersion properties, and are widely used in the range from visible to THz frequencies. In this study, asymmetric transmission properties of 2-D photonic crystals have been studied. The effects of different geometric and optical parameters on the transmission are investigated by using MATLAB and freely available MEEP software based on the FDTD method. A novel structure made of silver is used to manipulate electromagnetic propagation of different wave lengths. The simulation results represent transmittance values for the TM mode where the electromagnetic propagation transverse to the same way of incidence wave. As a result, the best comparative asymmetric transmittance values are obtained as 0.75, and 0.15 from top and bottom sides, respectively.