Documents disponibles écrits par cet auteur

Analytical approach for detection of multiple cracks in a beam / Xiaoqing, Zhang in Journal of engineering mechanics, Vol. 136 N° 3 (Mars 2010) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 136 N° 3 (Mars 2010) . - pp. 345-357 Titre : Analytical approach for detection of multiple cracks in a beam Type de document : texte imprimé Auteurs : Xiaoqing, Zhang, Auteur ; Qiang, Han, Auteur ; Feng, Li, Auteur Article en page(s) : pp. 345-357 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Cracking  Vibration  Beams  Analytical  techniques. Résumé : An analytical approach for the detection of a beam with multiple cracks is presented in this article. The method is based on the bending vibration theory of Euler-Bernoulli beam and the cracks are treated as massless rotational springs, by which the cracked beam is separated into a number of segments of perfect beams. By using the nontrivial solution condition of the vibration mode of the beam elements, specially using the transfer matrix method for the multiple cracks detection, the crack identification equation of the cracked beam is obtained explicitly, which is a function of natural frequencies, the locations, and depths of the cracks. Since the natural frequencies of a cracked beam can be measured through many of the structural testing methods, then the relations of the locations and the depths of the cracks can be determined explicitly from the identification equation of a cracked beam which geometrical and physical parameters as well as the boundary conditions are given. The results of some examples are shown and the present method is validated with the existing and measured experimental data. The detection for other types of beams with different number of cracks and various boundary conditions can also be obtained by a similar procedure. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JENMDT&ON [article] Analytical approach for detection of multiple cracks in a beam [texte imprimé] / Xiaoqing, Zhang, Auteur ; Qiang, Han, Auteur ; Feng, Li, Auteur . - pp. 345-357. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 136 N° 3 (Mars 2010) . - pp. 345-357 Mots-clés : Cracking  Vibration  Beams  Analytical  techniques. Résumé : An analytical approach for the detection of a beam with multiple cracks is presented in this article. The method is based on the bending vibration theory of Euler-Bernoulli beam and the cracks are treated as massless rotational springs, by which the cracked beam is separated into a number of segments of perfect beams. By using the nontrivial solution condition of the vibration mode of the beam elements, specially using the transfer matrix method for the multiple cracks detection, the crack identification equation of the cracked beam is obtained explicitly, which is a function of natural frequencies, the locations, and depths of the cracks. Since the natural frequencies of a cracked beam can be measured through many of the structural testing methods, then the relations of the locations and the depths of the cracks can be determined explicitly from the identification equation of a cracked beam which geometrical and physical parameters as well as the boundary conditions are given. The results of some examples are shown and the present method is validated with the existing and measured experimental data. The detection for other types of beams with different number of cracks and various boundary conditions can also be obtained by a similar procedure. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JENMDT&ON

Visible-light-induced photocatalyst based on cobalt-doped zinc ferrite nanocrystals / Guoli Fan in Industrial & engineering chemistry research, Vol. 51 N° 42 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 42 (Octobre 2012) . - pp. 13639-13647 Titre : Visible-light-induced photocatalyst based on cobalt-doped zinc ferrite nanocrystals Type de document : texte imprimé Auteurs : Guoli Fan, Auteur ; Ji Tong, Auteur ; Feng, Li, Auteur Année de publication : 2012 Article en page(s) : pp. 13639-13647 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanocrystal  Photocatalysis  Catalyst  Visible  radiation Résumé : The present work reported the synthesis of visible-light-induced cobalt-doped zinc ferrite (Zn1-xCoxFe2O4) photocatalysts via a facile reduction―oxidation route, which involved rapid reduction of Fe3+ and Co2+ cations in colloid mill reactor, followed by oxidation of iron and cobalt nuclei and structural transformation under hydrothermal conditions. The structural and optical properties of materials were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV―vis diffuse reflectance spectra. The results indicated that metallic Co and Fe nuclei could be obtained by reduction in the colloid mill, and Zn1-xCoxFe2O4 nanocrystals with uniform size were successfully achieved. Furthermore, compared to ZnFe2O4, Zn1-xCoxFe2O4 samples (x = 0.03, 0.1, 0.2) exhibited enhanced photocatalytic activity in the degradation of methylene blue under visible light irradiation. Especially, the Zn0.8Co0.2Fe2O4 sample had the highest photocatalytic activity, which was mainly attributable to its smaller band edge. Since as-synthesized Zn-Co ferrites nanocrystals have the advantages of intrinsic chemical stability and magnetic property, it can be expected that they may have potential application in the field of industrial photodegradation of organic pollutants. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26508188 [article] Visible-light-induced photocatalyst based on cobalt-doped zinc ferrite nanocrystals [texte imprimé] / Guoli Fan, Auteur ; Ji Tong, Auteur ; Feng, Li, Auteur . - 2012 . - pp. 13639-13647. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 42 (Octobre 2012) . - pp. 13639-13647 Mots-clés : Nanocrystal  Photocatalysis  Catalyst  Visible  radiation Résumé : The present work reported the synthesis of visible-light-induced cobalt-doped zinc ferrite (Zn1-xCoxFe2O4) photocatalysts via a facile reduction―oxidation route, which involved rapid reduction of Fe3+ and Co2+ cations in colloid mill reactor, followed by oxidation of iron and cobalt nuclei and structural transformation under hydrothermal conditions. The structural and optical properties of materials were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV―vis diffuse reflectance spectra. The results indicated that metallic Co and Fe nuclei could be obtained by reduction in the colloid mill, and Zn1-xCoxFe2O4 nanocrystals with uniform size were successfully achieved. Furthermore, compared to ZnFe2O4, Zn1-xCoxFe2O4 samples (x = 0.03, 0.1, 0.2) exhibited enhanced photocatalytic activity in the degradation of methylene blue under visible light irradiation. Especially, the Zn0.8Co0.2Fe2O4 sample had the highest photocatalytic activity, which was mainly attributable to its smaller band edge. Since as-synthesized Zn-Co ferrites nanocrystals have the advantages of intrinsic chemical stability and magnetic property, it can be expected that they may have potential application in the field of industrial photodegradation of organic pollutants. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26508188