Showing 3 results for Sari
Mohammad Ali Ansari,
Volume 6, Issue 2 (International Journal of Optics and Photonics (IJOP) Vol 6, No 2, Summer-Fall 2012)
Abstract
In this paper, the evaluation of time profile of a femtosecond pulse laser propagated through biological tissues is studied. The majority of the biological tissues with a high scattering anisotropy must be considered as turbid media, that their optical responses are complicated. To study the propagation of ultra-short pulse in turbid media, the diffuse equation is used. In this study, the analytical and numerical solution for diffuse equation is investigated. The numerical method is based on Boundary Integral method (BIM), and also, the time evaluation of propagating pulse is studied.
Dr Mohammad Ali Ansari, Dr Ezeddin Mohajerani,
Volume 8, Issue 2 (International Journal of Optics and Photonics (IJOP) Vol 8, No 2, Summer-Fall 2014)
Abstract
The Image reconstruction is an important problem in optical tomography. The process of the image processing requires the study of photon migration in biological tissue. There are several approaches to study and simulate propagation of photons in biological tissues. These approaches are categorized into stochastic and analytical groups. The Monte Carlo method as a stochastic method is widely used to simulate the propagation of photons in biological tissues which is time consuming. In other hand, the diffuse equation can be also applied to simulate the migration of photons in tissues. In this study, a solution to diffuse equation based on green theorem is applied to study the diffusion of photon in biological tissue. The precision and accuracy of this presented method is evaluated by comparing with Monte Carlo method and experimental Data.
Reza Pourahmad, Sheila Shahidi, Amirhossein Sari, Mohammadreza Hantezadeh,
Volume 17, Issue 1 (Winter-Spring 2023)
Abstract
In this research, an attempt is made to approach a specific type of carbon, such as graphene or carbon nanotubes by using pulsed laser ablation technique in deionized water environment with changing the laser factors such as wavelength and fluence. Nd:YAG laser with two wavelengths of 1064 and 532 nm and three fluence of 0.8, 1 and 1.2 J/cm2 were selected that number of pulses was 5000 with a frequency of 10 Hz to be irradiated on the graphite target at about 10 minutes. The medium was distilled water. Graphite was located in the 40 ml of distilled water.
The effects of wavelength and fluence of the laser have been experimentally investigated on types of carbon characteristics with different analysis such as Raman scattering spectrum, FE-SEM images, UV–Vis-NIR spectrum and X-ray diffraction (XRD). By using the mentioned analysis, the type of synthesized nano carbon is studied.
This study evaluates the effects of the pulse energy and laser wavelength on properties of synthesized carbon nanoparticle in laser ablation method in medium of distilled water.