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Wang Y.,Jilin University | Chen A.,Jilin University | Chen A.,State Key Laboratory of Laser Propulsion and Application | Li S.,Jilin University | And 5 more authors.
Journal of Analytical Atomic Spectrometry | Year: 2016

In this paper, we propose and demonstrate a study of Fe plasma using collinear dual-wavelength femtosecond double-pulse laser-induced breakdown spectroscopy (LIBS) with a fundamental wavelength (800 nm) and a second harmonic wavelength (400 nm) from Ti:sapphire laser. By varying the time separation of the dual-wavelength femtosecond double-pulse, the experimental results clearly show the signal enhancement up to a factor of 10 and more than 10 times, in comparison with it at 0 ps time separation. The electron temperature and electron density are analyzed as the basic parameters of plasma properties, and they are respectively based on the theory of Boltzmann plot and Stark broadening. It proves that dual-wavelength femtosecond double-pulse LIBS is excellent for enhancing the emission intensity of the signal. © 2016 The Royal Society of Chemistry. Source


Chang H.,Academy of Equipment Command and Technology | Jin X.,State Key Laboratory of Laser Propulsion and Application | Chen Z.,Beijing University of Chemical Technology
Guangxue Xuebao/Acta Optica Sinica | Year: 2013

In the process of laser ablation, the target's absorption coefficient, thermal conductivity, density and surface reflectivity are dependent on its temperature. When the target surface temperature approaches the thermodynamic critical temperature Tc, the high-temperature part of the target transits from metal to nonmetal. The target is divided into two temperature regions (below and above 0.8Tc) and a model is built up to calculate the above physical parameters. The temporal and spatial distribution of temperature, absorption coefficient and thermal conductivity of Al target are obtained by a one-dimensional heat conduction equation. Ablation depth is calculated as a function of laser pulse energies. Numerical results are in good agreement with the experimental results, which validate the presented model. Source


Song Y.L.,China Agricultural University | Huang F.,China Agricultural University | Chen Z.Y.,Beijing University of Chemical Technology | Chen Z.Y.,State Key Laboratory of Laser Propulsion and Application | And 3 more authors.
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2016

Negatively charged dust particles immersed in 2-dimensional dusty plasma system are investigated by molecular dynamics simulations. The effects of the confinement potential and attraction interaction potential on dust particle self-organization are studied in detail and two typical dust particle distributions are obtained when the system reaches equilibrium. The average radial velocity (ARV), average radial force (ARF) and radial mean square displacement are employed to analyze the dust particles' dynamics. Both ARVs and ARFs exhibit oscillation behaviors when the simulation system reaches equilibrium state. The relationships between the oscillation and confinement potential and attraction potential are studied in this paper. The simulation results are qualitatively similar to experimental results. © 2015 Elsevier B.V. All rights reserved. Source


Zhang D.,Academy of Equipment Command and Technology | Yang Y.,Academy of Equipment Command and Technology | Li X.,Academy of Equipment Command and Technology | Li X.,State Key Laboratory of Laser Propulsion and Application
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

A thermal effect model is presented in this paper, with the background of ground-based laser irradiating moving and rotating target in the air. Firstly, the encounter scene of laser irradiating target is assumed, and the main parameters of laser and target are given. Secondly, the calculation model of irradiating parameters is derived, including irradiating area, power density distribution and convection heat transfer per unit area. Thirdly, the thermal effect model is established to describe heat conduction and thermal ablation during laser irradiating. Finally, the thermal effects are calculated by assuming the parameters in encounter scene of laser irradiating target. As shown in the example, the thermal effect model can minutely describe the temperature field and ablation results of moving and rotating target irradiated by laser. © 2015 SPIE. Source


Yang Y.,Academy of Equipment Command and Technology | Zhang D.,Academy of Equipment Command and Technology | Li X.,Academy of Equipment Command and Technology | Li X.,State Key Laboratory of Laser Propulsion and Application
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

Future space missions may use laser power beaming systems with a high power laser to transmit light to a photovoltaic array receiver. The photovoltaic array receiver can be mounted to a satellite or a spacecraft. To investigate the V-I and P-V characteristics of photovoltaic cells (PV cells) under laser illumination, a mathematical model and simulation model related to the voltage and current of PV cells is studied. Based on the MATLAB simulation tool, the simulated V-I and P-V characteristics of PV cells for various irradiances are presented. To validate the simulated results, three experiments are designed. The results obtained by experimenting are compared with the simulated results, and the difference between them is not apparent.. © 2015 SPIE. Source

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