Loading...
Search for:
effect-of-pulse
0.009 seconds
Improvement of laser-driven proton beam quality by optimized intense chirped laser pulses
, Article Physics of Plasmas ; Volume 25, Issue 1 , 2018 ; 1070664X (ISSN) ; Amrollahi, R ; Sadighi Bonabi, R ; Sharif University of Technology
American Institute of Physics Inc
2018
Abstract
The effect of pulse shaping on the intense laser-driven proton beam produced through radiation pressure acceleration as a highly efficient mechanism is investigated. In this regard, the interaction of pulses with modified frequencies, including positive and negative chirped pulses with plasma, is simulated using particle-in-cell code. The simulation results indicate that the proton acceleration could be significantly enhanced for both negative and positive chirped pulses. As a consequence of the acceleration time extension as well as the electron heating suppression, a sharper and narrower proton beam could be achieved for negative chirped pulses. The same trend is observed for all negative...
Pulsed electrodeposition and characterization of bronze-graphite composite coatings
, Article Surface and Coatings Technology ; Volume 203, Issue 20-21 , 2009 , Pages 3037-3043 ; 02578972 (ISSN) ; Ghorbani, M ; Sharif University of Technology
2009
Abstract
Composite coatings containing self-lubricant particles like graphite, MoS2, PTFE are extensively used to decrease the coefficient of friction of tribo-surfaces. The aim of this study is to investigate the effect of pulse electrodeposition parameters on particle codeposition process and characteristics of bronze-graphite composite coatings electrodeposited from cyanide-stannate bronze electroplating bath. Results showed a slight increase in tin content and a promising increase in hardness of bronze coating by a decrease in duty cycle at constant average current density. Both tin content of the coating and grain refinement seem to participate in hardness enhancement. By increasing the...
Polycarbonate surface cell's adhesion examination after Nd:YAG laser irradiation
, Article Materials Science and Engineering C ; Volume 29, Issue 4 , 2009 , Pages 1491-1497 ; 09284931 (ISSN) ; Mousavi, A ; Seyedjafari, E ; Poursalehi, R ; Sareh, S ; Silakhori, K ; Poorfatollah, A. A ; Shamkhali, A. N ; Sharif University of Technology
2009
Abstract
Nd:YAG laser treatment was used in order to increase surface cell adhesion aspects of polycarbonate (PC) films prepared via melt process. The treatment was carried out under different wavelengths and beam diameters. ATR-FTIR and UV spectra obtained from different samples before and after laser treatment in air showed that laser irradiation has induced some chemical and physical changes in surface properties. The irradiated films were also characterized using scanning electron microscopy (SEM) and contact angle measurements. Effect of pulse numbers on the surface properties was also investigated. Cell culture test was used to evaluate cell adhesion property on the PC films before and after...