Documents disponibles écrits par cet auteur

Modeling of ultrafast phase change processes in a thin metal film irradiated by femtosecond laser pulse trains / Jing Huang in Journal of heat transfer, Vol. 133 N° 3 (Mars 2011) 

Public ISBD [article]  in Journal of heat transfer > Vol. 133 N° 3 (Mars 2011) . - pp. [031003/1-8] Titre : Modeling of ultrafast phase change processes in a thin metal film irradiated by femtosecond laser pulse trains Type de document : texte imprimé Auteurs : Jing Huang, Auteur ; Yuwen Zhang, Auteur ; J. K. Chen, Auteur Année de publication : 2011 Article en page(s) : pp. [031003/1-8] Note générale : Physique Langues : Anglais (eng) Mots-clés : Gold  Laser  beam  effects  Melting  Metallic  thin  films  Phase  change  materials  Solidification  Vaporisation Index. décimale : 536 Chaleur. Thermodynamique Résumé : Ultrashort laser pulses can be generated in the form of a pulse train. In this paper, the ultrafast phase change processes of a 1 µm free-standing gold film irradiated by femtosecond laser pulse trains are simulated numerically. A two-temperature model coupled with interface tracking method is developed to describe the ultrafast melting, vaporization, and resolidification processes. To deal with the large span in time scale, variable time steps are adopted. A laser pulse train consists of several pulse bursts with a repetition rate of 0.5–1 MHz. Each pulse burst contains 3–10 pulses with an interval of 50 ps–10 ns. The simulation results show that with such configuration, to achieve the same melting depth, the maximum temperature in the film decreases significantly in comparison to that of a single pulse. Although the total energy depositing on the film will be lifted, more energy will be transferred into the deeper part, instead of accumulating in the subsurface layer. This leads to lower temperature and temperature gradient, which is favorable in laser sintering and laser machining. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&smode=strresults& [...] [article] Modeling of ultrafast phase change processes in a thin metal film irradiated by femtosecond laser pulse trains [texte imprimé] / Jing Huang, Auteur ; Yuwen Zhang, Auteur ; J. K. Chen, Auteur . - 2011 . - pp. [031003/1-8]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 133 N° 3 (Mars 2011) . - pp. [031003/1-8] Mots-clés : Gold  Laser  beam  effects  Melting  Metallic  thin  films  Phase  change  materials  Solidification  Vaporisation Index. décimale : 536 Chaleur. Thermodynamique Résumé : Ultrashort laser pulses can be generated in the form of a pulse train. In this paper, the ultrafast phase change processes of a 1 µm free-standing gold film irradiated by femtosecond laser pulse trains are simulated numerically. A two-temperature model coupled with interface tracking method is developed to describe the ultrafast melting, vaporization, and resolidification processes. To deal with the large span in time scale, variable time steps are adopted. A laser pulse train consists of several pulse bursts with a repetition rate of 0.5–1 MHz. Each pulse burst contains 3–10 pulses with an interval of 50 ps–10 ns. The simulation results show that with such configuration, to achieve the same melting depth, the maximum temperature in the film decreases significantly in comparison to that of a single pulse. Although the total energy depositing on the film will be lifted, more energy will be transferred into the deeper part, instead of accumulating in the subsurface layer. This leads to lower temperature and temperature gradient, which is favorable in laser sintering and laser machining. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&smode=strresults& [...]

Online synchronous machine parameter extraction from small-signal injection techniques / Jing Huang in IEEE transactions on energy conversion, Vol. 24 N°1 (Mars 2009) 

Public ISBD [article]  in IEEE transactions on energy conversion > Vol. 24 N°1 (Mars 2009) . - pp. 43 - 51 Titre : Online synchronous machine parameter extraction from small-signal injection techniques Type de document : texte imprimé Auteurs : Jing Huang, Auteur ; Corzine, K. A., Auteur ; Belkhayat, M., Auteur Année de publication : 2009 Article en page(s) : pp. 43 - 51 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : Choppers  (circuits);  genetic  algorithms;  machine  control;  parameter  estimation;  synchronous  machines Résumé : This paper proposes using a novel line-to-line voltage perturbation as a technique for online measurement of synchronous machine parameters. The perturbation is created by a chopper circuit connected between two phases of the machine. Using this method, it is possible to obtain the full set of four complex small-signal impedances of the synchronous machine d-q model over a wide frequency range. Typically, two chopper switching frequencies are needed to obtain one data point. However, it is shown herein that, due to the symmetry of the machine equations, only one chopper switching frequency is needed to obtain the information. A 3.7-kW machine system is simulated, and then constructed for validation of the impedance measurement technique. A genetic algorithm is then used to obtain IEEE standard model parameters from the d -q impedances. The resulting parameters are shown to be similar to those obtained by a series of tests involving synchronous reactance measurements and a standstill frequency response. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4783111&sortType%3Das [...] [article] Online synchronous machine parameter extraction from small-signal injection techniques [texte imprimé] / Jing Huang, Auteur ; Corzine, K. A., Auteur ; Belkhayat, M., Auteur . - 2009 . - pp. 43 - 51. energy conversion Langues : Anglais (eng) in IEEE transactions on energy conversion > Vol. 24 N°1 (Mars 2009) . - pp. 43 - 51 Mots-clés : Choppers  (circuits);  genetic  algorithms;  machine  control;  parameter  estimation;  synchronous  machines Résumé : This paper proposes using a novel line-to-line voltage perturbation as a technique for online measurement of synchronous machine parameters. The perturbation is created by a chopper circuit connected between two phases of the machine. Using this method, it is possible to obtain the full set of four complex small-signal impedances of the synchronous machine d-q model over a wide frequency range. Typically, two chopper switching frequencies are needed to obtain one data point. However, it is shown herein that, due to the symmetry of the machine equations, only one chopper switching frequency is needed to obtain the information. A 3.7-kW machine system is simulated, and then constructed for validation of the impedance measurement technique. A genetic algorithm is then used to obtain IEEE standard model parameters from the d -q impedances. The resulting parameters are shown to be similar to those obtained by a series of tests involving synchronous reactance measurements and a standstill frequency response. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4783111&sortType%3Das [...]

Size effects during femtosecond laser interaction with nanosized metal particles / Jing Huang in Journal of heat transfer, Vol. 134 N° 1 (Janvier 2012) 

Public ISBD [article]  in Journal of heat transfer > Vol. 134 N° 1 (Janvier 2012) . - 07 p. Titre : Size effects during femtosecond laser interaction with nanosized metal particles Type de document : texte imprimé Auteurs : Jing Huang, Auteur ; Yuwen Zhang, Auteur ; J. K. Chen, Auteur Année de publication : 2012 Article en page(s) : 07 p. Note générale : Heat teansfer Langues : Anglais (eng) Mots-clés : Evaporation  Gold  High-speed  optical  techniques  Laser  beam  effects  Laser  sintering  Melting  Nanoparticles  Particle  size  Solidification Index. décimale : 536 Chaleur. Thermodynamique Résumé : To obtain more in-depth knowledge about the microscopic process during laser sintering, phase change processes including melting, evaporation, and resolidification during the irradiation of femtosecond laser on nanosized gold particles were simulated. The effects of multiple reflections and pulse energy overlapping in small particle size were considered. The results show that when the particle size is big enough, the simulation results match those of old model. When the particle size is small and laser fluence is high, no resolidification takes place in the time range of the simulation. The laser fluence range to achieve partial melting is narrow when the particle is small. When the diameter is smaller than 400 nm, temperature gradient during the heating period is ignorable, which is different from the large particles. The threshold value of laser fluence to achieve vaporization is about two times higher than that of melting with the same particle size. DEWEY : 536 ISSN : 0022-1481 En ligne : http://www.asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO00013400 [...] [article] Size effects during femtosecond laser interaction with nanosized metal particles [texte imprimé] / Jing Huang, Auteur ; Yuwen Zhang, Auteur ; J. K. Chen, Auteur . - 2012 . - 07 p. Heat teansfer Langues : Anglais (eng) in Journal of heat transfer > Vol. 134 N° 1 (Janvier 2012) . - 07 p. Mots-clés : Evaporation  Gold  High-speed  optical  techniques  Laser  beam  effects  Laser  sintering  Melting  Nanoparticles  Particle  size  Solidification Index. décimale : 536 Chaleur. Thermodynamique Résumé : To obtain more in-depth knowledge about the microscopic process during laser sintering, phase change processes including melting, evaporation, and resolidification during the irradiation of femtosecond laser on nanosized gold particles were simulated. The effects of multiple reflections and pulse energy overlapping in small particle size were considered. The results show that when the particle size is big enough, the simulation results match those of old model. When the particle size is small and laser fluence is high, no resolidification takes place in the time range of the simulation. The laser fluence range to achieve partial melting is narrow when the particle is small. When the diameter is smaller than 400 nm, temperature gradient during the heating period is ignorable, which is different from the large particles. The threshold value of laser fluence to achieve vaporization is about two times higher than that of melting with the same particle size. DEWEY : 536 ISSN : 0022-1481 En ligne : http://www.asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO00013400 [...]