Nonlinear optical signal enhancement cannot be achieved by using semiconductor materials alone. Here, we show that the recently discovered nonlinear optical behavior of plasmonic nanoparticles and hybrid nanowires enables an enhanced nonlinear optical response. A synthesis, characterization, and nonlinear optical response of synthesized hybrid nanowires structures were studied. The growth of gold nanoparticles (Au NPs) onto cadmium selenide nanowires CdSe NWs with different concentrations of gold nanoparticles coating prepared via an impregnation technique. Au nanoparticles in the CdSe/Au nanowires were uniformly dispersed on the CdSe nanowire surface. The surface morphologies and the propagation manner of hybrid nanostructures were used for transmission electron microscopy (TEM) to study the optical properties of pure and hybrid nanostructures. Dark-field scattering microscopy was used to characterize single CdSe NW and confirm the coating of hybrid CdSe/Au nanowires and characterize the concentration effect of gold nanoparticles. The dark-field scattering spectrum (DFSS) reference to the surface plasmon resonance of nearer Au NPs was observed at ca. 800 nm. By making a comparison between a single cadmium selenide with and without gold nanoparticles coating, hybrid CdSe/Au nanowires exhibit sufficient quality to produce second-harmonic generation stimulated with a pulsed, linearly polarized pump-light from a femtosecond Ti-sapphire laser. The estimated improvement of the second-harmonic generation signal is about ~ 1.8 times, ~ 5.5 times, ~ 6.9 times for low, moderate and full coating of gold nanoparticles, which was mainly due to the high quality of synthesis techniques and good dispersion of gold nanoparticles on CdSe nanowires

Background: This study focuses on the uranium concentration (UC), radium content (RC) and radon exhalation rates (RER) in selected food crops consumed in Babil governorate, in the centre of Iraq. Materials and Methods: Neutron activation technique and sealed cup with CR-39 alpha track detector were used respectively to investigate the natural radioactivity of selected food crops collected from Babil governorate, Iraq. Results: In the current study, the highest UC was found to be 0.0346 ppm in the turnip crop, whereas the lowest value of UC (0.0142 ppm) was found in grape crop. The highest RC was found to be 0.651 Bq/kg in turnip, while the lowest RC (0.169 Bq/kg) was found in the fig crop. The values of RER ranged from 0.016 Bq/m 2 .h found in the fig to 0.065 Bq/m 2 .h found in the turnip. Conclusion: The levels of UC in food crops were lower than 1.7 ppm, the recommended limits of UNSCEAR. A strong direct correlation was found between the UC and RC in selected food crops.