Effect of ambient gas pressure on nanosecond laser produced plasma on nickel thin film in a forward ablation geometry

2018 ◽  
Vol 25 (10) ◽  
pp. 103108 ◽  
Author(s):  
Jinto Thomas ◽  
Hem Chandra Joshi ◽  
Ajai Kumar ◽  
Reji Philip
2017 ◽  
Vol 9 (34) ◽  
pp. 28139-28143 ◽  
Author(s):  
Boya Cui ◽  
Cornelius O. Audu ◽  
Yijun Liao ◽  
SonBinh T. Nguyen ◽  
Omar K. Farha ◽  
...  

2011 ◽  
Vol 227 ◽  
pp. 129-133
Author(s):  
Farida Hamadi ◽  
El Hachemi Amara

In this paper we present a numerical modeling of a nanosecond laser pulse interaction with a titanium target. We investigate the vapor plume formation and the influence of the ambient gas pressure on plume expansion dynamics. The vapor plume formation depends on the results of the heat transfer in the solid target modeling. The solid-liquid phase change is modeled by a two dimensional approach using an enthalpy formulation. The resulting plume expansion in the argon background gas is studied using the species transport model. The algebraic equations are discretized by the finite volume method implemented by Fluent CFD software [1]. The calculation results of plume expansion velocity, density, temperature and degree of ionization in the plume are presented.


2020 ◽  
Vol 69 (5) ◽  
pp. 057401
Author(s):  
Jia-He Liu ◽  
Jia-Zhe Lu ◽  
Jun-Jie Lei ◽  
Xun Gao ◽  
Jing-Quan Lin

2004 ◽  
Vol 446 (2) ◽  
pp. 178-183 ◽  
Author(s):  
E. György ◽  
I.N. Mihailescu ◽  
M. Kompitsas ◽  
A. Giannoudakos

2021 ◽  
pp. 1-6
Author(s):  
Serap Yiğit Gezgin ◽  
Abdullah Kepceoğlu ◽  
Hamdi Şükür Kiliç

In this study, silver (Ag) nanoparticle thin films were deposited on microscope slide glass and Si wafer substrates using the pulsed-laser deposition (PLD) technique in Ar ambient gas pressures of 1 × 10−3 and 7.5 × 10−1 mbar. AFM analysis has shown that the number of Ag nanoparticles reaching the substrate decreased with increasing Ar gas pressure. As a result of Ar ambient gas being allowed into the vacuum chamber, it was observed that the size and height of Ag nanoparticles decreased and the interparticle distances decreased. According to the absorption spectra taken by a UV–vis spectrometer, the wavelength where the localised surface plasmon resonance (LSPR) peak appeared was shifted towards the longer wavelength region in the solar spectrum as Ar background gas pressure was decreased. This experiment shows that LSPR wavelength can be tuned by adjusting the size of metal nanoparticles, which can be controlled by changing Ar gas pressure. The obtained extinction cross section spectra for Ag nanoparticle thin film was theoretically analysed and determined by using the metal nanoparticle–boundary element method (MNPBEM) toolbox simulation program. In this study, experimental spectrum and simulation data for metal nanoparticles were acquired, compared, and determined to be in agreement.


2012 ◽  
Vol 111 (7) ◽  
pp. 07A304 ◽  
Author(s):  
Feng Xu ◽  
Qijun Huang ◽  
Zhiqin Liao ◽  
Shandong Li ◽  
C. K. Ong

2000 ◽  
Vol 655 ◽  
Author(s):  
Masanori Okuyama ◽  
Toshiyuki Nakaiso ◽  
Minoru Noda

AbstractSr2(Ta1划x, Nbx)2O7(STN) ferroelectric thin films have been prepared on SiO2/Si(100) substrates by the pulsed laser deposition (PLD) method. Preferential (110) and (151)-oriented STN thin films are deposited at a low temperature of 600°C in N2O ambient gas at 0.08 Torr. A counterclockwise C-V hysteresis was observed in the metal-ferroelectric-insulator-semiconductor (MFIS) structure using Sr2(Ta0.7, Nb0.3)2O7 on SiO2/Si deposited at 600°C. Memory window in the C-V curve spreads symmetrically towards both positive and negative directions when applied voltage increases and the window does not change in sweep rates ranging from 0.1 to 4.0×103 V/s. The C-V curve of the MFIS structure does not degrade after 1010 cycles of polarization reversal. The gate retention time is about 3.0×103 sec when the voltages and time of write pulse are ±15V and 1.0 sec, respectively, and hold bias was -0.5 V.


Author(s):  
Srinibas Tripathy ◽  
Sridhar Sahoo ◽  
Dhananjay Kumar Srivastava

Computational fluid dynamics (CFD) plays a tremendous role in evaluating and visualizing the spray breakup, atomization and vaporization process. In this study, ANSYS Forte CFD tool was used to simulate the spray penetration length and spray morphology in a constant volume chamber at different grid size of a multi-hole injector. An unsteady gas jet model was coupled with Kelvin-Helmholtz (KH) and Rayleigh-Taylor (RT) model for multi-hole spray simulation. The effect of CFD cell size and ambient gas pressure on spray penetration length and spray morphology of fuel vapor mass fraction were investigated for both KH-RT and KH-RT with the unsteady gas jet model. It is found that KH-RT with the unsteady gas jet model shows mesh independent spray penetration length and spray morphology of fuel vapor mass fraction as compared to KH-RT model. This can be explained by the Lagrangian-Eulerian coupling of axial droplet-gas relative velocity is modeled on the principle of unsteady gas jet theory instead of discretizing very fine grid to the computational domain. This reduces the requirement of fine mesh near the nozzle and allows larger time step during spray injection. It is also observed that at higher ambient gas pressure, an aerodynamic force between the droplet and gas intensifies which reduces the overall spray penetration length and fuel vapor mass. The distorted spray morphology of fuel vapor mass fraction was accurately predicted at high ambient gas pressure using the KH-RT with an unsteady gas jet model which results in mesh independent drag predictions. The use of advanced spray model results in the mesh size dependency reduction and accurate drag prediction with less computational time and faster accurate solutions over all conventional spray breakup models.


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