Documents disponibles écrits par cet auteur

Effect of surface roughness on single cryogen droplet spreading / Jie Liu in Transactions of the ASME . Journal of fluids engineering, Vol. 130 N° 4 (Avril 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 130 N° 4 (Avril 2008) . - 9 p. Titre : Effect of surface roughness on single cryogen droplet spreading Type de document : texte imprimé Auteurs : Jie Liu, Auteur ; Walfre, Franco, Auteur ; Guillermo Aguilar, Auteur Année de publication : 2009 Article en page(s) : 9 p. Note générale : Fluids engineering Langues : Anglais (eng) Mots-clés : Dynamics  (mechanics);  friction;  surface  roughness;  energy  dissipation;  skin;  sprays Résumé : Cryogen spray cooling is an auxiliary procedure to dermatologic laser surgery, which consists of precooling the superficial skin layer (epidermis) during laser irradiation of subsurface targets to avoid nonspecific epidermal thermal damage. While previous studies have investigated the interaction of cryogen sprays with microscopically smooth human skin models, it is important to recognize that real human skin surface is far from smooth. With the objective to provide physical insight into the interaction between cryogen sprays and human skin, we study the effect of surface roughness on the impact dynamics of single cryogen droplets falling on skin models of various roughnesses (0.5–70μm). We first develop a theoretical model to predict the maximum spread diameter (Dm) following droplet impingement based on a similarity approximation to the solution of a viscous boundary layer that incorporates friction as the major source of viscous dissipation on a rough surface. Then, we measure the droplet diameter, impact velocity, and Dm of cryogen droplets falling by gravity onto skin models. Experimental data prove that the proposed model predicts Dm with good accuracy, suggesting that the effects of surface roughness and friction on Dm are properly taken into account for the range of surface roughness studied herein. En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/Issue.aspx?issueID=27307 [...] [article] Effect of surface roughness on single cryogen droplet spreading [texte imprimé] / Jie Liu, Auteur ; Walfre, Franco, Auteur ; Guillermo Aguilar, Auteur . - 2009 . - 9 p. Fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 130 N° 4 (Avril 2008) . - 9 p. Mots-clés : Dynamics  (mechanics);  friction;  surface  roughness;  energy  dissipation;  skin;  sprays Résumé : Cryogen spray cooling is an auxiliary procedure to dermatologic laser surgery, which consists of precooling the superficial skin layer (epidermis) during laser irradiation of subsurface targets to avoid nonspecific epidermal thermal damage. While previous studies have investigated the interaction of cryogen sprays with microscopically smooth human skin models, it is important to recognize that real human skin surface is far from smooth. With the objective to provide physical insight into the interaction between cryogen sprays and human skin, we study the effect of surface roughness on the impact dynamics of single cryogen droplets falling on skin models of various roughnesses (0.5–70μm). We first develop a theoretical model to predict the maximum spread diameter (Dm) following droplet impingement based on a similarity approximation to the solution of a viscous boundary layer that incorporates friction as the major source of viscous dissipation on a rough surface. Then, we measure the droplet diameter, impact velocity, and Dm of cryogen droplets falling by gravity onto skin models. Experimental data prove that the proposed model predicts Dm with good accuracy, suggesting that the effects of surface roughness and friction on Dm are properly taken into account for the range of surface roughness studied herein. En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/Issue.aspx?issueID=27307 [...]

Flame synthesis of ball-in-shell structured TiO2 nanospheres / Jie Liu in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) Titre : Flame synthesis of ball-in-shell structured TiO2 nanospheres Type de document : texte imprimé Auteurs : Jie Liu, Auteur ; Yanjie Hu, Auteur ; Feng Gu, Auteur ; Chunzhong Li, Auteur Année de publication : 2009 Note générale : chemical engeneering Langues : Anglais (eng) Mots-clés : Nanosphereselectron  microscopy Résumé : Ball-in-shell structured TiO2 nanospheres were successfully made by flame synthesis—a single-step, continuous, and scalable process. The morphology and structure were systematically characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, scanning electron microscopy, and N2 sorption. TiO2 nanostructures with good crystalline nature and thermal stability were formed by feeding a titanium tetrachloride and alcohol vapor mixture to a facile diffusion flame. The resultant ball-in-shell spheres were composed of nanocrystallites, with shell thickness and void space width of 30−50 nm and 10−30 nm, respectively. The formation mechanism of ball-in-shell spheres was investigated, depending on the competition between the chemical reaction rate and diffusion rate during the flame process. Furthermore, UV−vis characterization indicates that this structure endows the spheres with higher light absorbance, which may be favorable to design and prepare novel materials with enhanced photocatalytic activities. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800986j [article] Flame synthesis of ball-in-shell structured TiO2 nanospheres [texte imprimé] / Jie Liu, Auteur ; Yanjie Hu, Auteur ; Feng Gu, Auteur ; Chunzhong Li, Auteur . - 2009. chemical engeneering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) Mots-clés : Nanosphereselectron  microscopy Résumé : Ball-in-shell structured TiO2 nanospheres were successfully made by flame synthesis—a single-step, continuous, and scalable process. The morphology and structure were systematically characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, scanning electron microscopy, and N2 sorption. TiO2 nanostructures with good crystalline nature and thermal stability were formed by feeding a titanium tetrachloride and alcohol vapor mixture to a facile diffusion flame. The resultant ball-in-shell spheres were composed of nanocrystallites, with shell thickness and void space width of 30−50 nm and 10−30 nm, respectively. The formation mechanism of ball-in-shell spheres was investigated, depending on the competition between the chemical reaction rate and diffusion rate during the flame process. Furthermore, UV−vis characterization indicates that this structure endows the spheres with higher light absorbance, which may be favorable to design and prepare novel materials with enhanced photocatalytic activities. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800986j

Tin oxide nanowires synthesized via flat flame deposition / Jie Liu in Industrial & engineering chemistry research, Vol. 50 N° 9 (Mai 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5584-5588 Titre : Tin oxide nanowires synthesized via flat flame deposition : structures and formation mechanism Type de document : texte imprimé Auteurs : Jie Liu, Auteur ; Yanjie Hu, Auteur ; Feng Gu, Auteur Année de publication : 2011 Article en page(s) : pp. 5584-5588 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Formation  mechanism  Flame Résumé : Premixed atmospheric flat flame deposition is a large-scale composite fabrication method that combined the advantages of flame synthesis and thermal evaporation. The technology has been successfully developed to sythesize SnO2 nanowires. The results showed that the as-prepared SnO2 nanowires with special tips are uniform single crystals, growing along [001] direction. Meanwhile, the growth mechanism of the present novel structure, which is a combination of both a vapor-solid ( VS) growth mechanism and a particle formation mechanism in a flame without any catalyst, is also proposed, Furthermore, the optical property is investigated by photoluminescence (PL) spectroscopy, indicating that such SnO2 nanowires exhibit a much stronger emission peak at 620 nm. More importantly, this approach also provides a new pathway for sequentially engineering one-dimensional nanomaterials. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128681 [article] Tin oxide nanowires synthesized via flat flame deposition : structures and formation mechanism [texte imprimé] / Jie Liu, Auteur ; Yanjie Hu, Auteur ; Feng Gu, Auteur . - 2011 . - pp. 5584-5588. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5584-5588 Mots-clés : Formation  mechanism  Flame Résumé : Premixed atmospheric flat flame deposition is a large-scale composite fabrication method that combined the advantages of flame synthesis and thermal evaporation. The technology has been successfully developed to sythesize SnO2 nanowires. The results showed that the as-prepared SnO2 nanowires with special tips are uniform single crystals, growing along [001] direction. Meanwhile, the growth mechanism of the present novel structure, which is a combination of both a vapor-solid ( VS) growth mechanism and a particle formation mechanism in a flame without any catalyst, is also proposed, Furthermore, the optical property is investigated by photoluminescence (PL) spectroscopy, indicating that such SnO2 nanowires exhibit a much stronger emission peak at 620 nm. More importantly, this approach also provides a new pathway for sequentially engineering one-dimensional nanomaterials. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128681