Showing 4 results for zare
Naser Hatefi-Kargan, Milad Zare-Zardini,
Volume 12, Issue 1 (International Journal of Optics and Photonics (IJOP) Vol 12, No 1, Winter-Spring 2018)
Abstract
In this paper the transmittance of metal-insulator-metal (MIM) waveguides containing semi-circular ring shaped and rectangular ring shaped grooves are investigated. By varying groove parameters their effects on the transmittance of the MIM waveguides are investigated. The results show that the transmittance spectra of the waveguides have maximum and minimum points, and by using appropriate parameters for the grooves it is possible to make the transmittance maximum or minimum at a required frequency. Therefore by using the ring shaped grooves in the MIM waveguides a frequency splitter is designed. In comparison the efficiency of a MIM waveguide containing the ring shaped groove, on blocking the transmission of a required frequency, is higher than the efficiency of a MIM waveguide containing tooth shaped groove.
Hadi Zarei, Rasoul Malekfar,
Volume 12, Issue 1 (International Journal of Optics and Photonics (IJOP) Vol 12, No 1, Winter-Spring 2018)
Abstract
In this paper, tetragonal chalcopyrite (CIGS) Cu(InxGa1-x)Se2 with x=0, 0.5, 0.8, 1 are synthesized by heating-up method. These nanoparticle structures differ in morphology and absorption properties due to the synthesis temperatures of 250, 255, 260, 265, 270 and 280 ºC, and gallium molar ratio over the total gallium and indium contents. These features are studied using scanning electron microscope, X-ray diffraction and absorption spectroscopy in visible, ultra-violet and near-infrared wavelengths. Results indicate that by increasing gallium content, absorption edge rises toward the visible light. Any modification in the absorption edge changes the band gap and as a result the energy gap and the absorption of cell increases considerably. Also in the heating-up method, increasing the reaction temperature improves nanoparticles crystallites. This leads the absorption improvement and higher cells efficiency. Produced nanoparticles are spherical shape with are varying the diameter around 30-80 nm.
Ahmadzia Sherzad, Hakimeh Zare, Zahra Shahedi, Fatemeh Ostovari, Yousef Fazaeli, Zeinab Pourghobadi,
Volume 14, Issue 2 (Summer-Fall 2020)
Abstract
Luminescent graphene oxide quantum dots (GOQDs) have attracted tremendous attention from scientists in chemistry, materials, biology, and physics science. They have specific properties such as low cytotoxicity, excellent electrochemical and optical properties, resistance to photo-bleaching, and good stability. In this study, GOQDs were synthesized using a simple and straightforward methodology. The synthesized GOQDs were characterized by Fourier Transform Infrared (FTIR) analyzer, ultraviolet–visible spectrophotometry (UV–VIS) absorption, Photoluminescence (PL) spectroscopy, and transmission electron microscopy (TEM) analyses. Then, optical properties of GOQDs such as absorption and luminescence with various pH values were investigated. GOQDs show absorption in the ultraviolet (UV) region and their position of photoluminescence peak is independent of pH value. The average size of QDs is less than 5 nm, as revealed by TEM. The GOQDs show green luminescence under UV irradiation (360 nm).
Shima Haghgooyan, Fatemeh Ostovari, Hakimeh Zare, Zahra Shahedi,
Volume 16, Issue 1 (Winter-Spring 2022)
Abstract
ta charset="UTF-8" >Silk fibroin (SF) is a natural material that has received special attention due to its excellent mechanical and electrical properties. Nowadays, it is tried to improve the properties of SF by adding other nanomaterials such as graphene oxide (GO). Here, we extracted SF from silk cocoon and studied its properties in pure state and in the combination with graphene oxide (SF/GO). The results have shown that the presence of graphene oxide in the structure of fibroin increases the random winding formation of SF. The measurements show that the water content has a great effect on the properties of SF and SF/GO films. The contact angle (less than 70) indicates the hydrophilic property of these films. In addition, in times greater than 50 seconds, the contact angles drop to 27° and 5° for SF and SF/GO respectively. Also, the surface resistance of the completely dried SF/GO film increases from 50 kW/sq to 220 kW/sq for 42% wt water content.
