Documents disponibles écrits par cet auteur

An overview of mutual solubility of ionic liquids and water predicted by COSMO - RS / Teng Zhou in Industrial & engineering chemistry research, Vol. 51 N° 17 (Mai 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 17 (Mai 2012) . - pp. 6256-6264 Titre : An overview of mutual solubility of ionic liquids and water predicted by COSMO - RS Type de document : texte imprimé Auteurs : Teng Zhou, Auteur ; Long Chen, Auteur ; Yinmei Ye, Auteur Année de publication : 2012 Article en page(s) : pp. 6256-6264 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Ionic  liquid  Solubility Résumé : To properly screen and use ionic liquids (ILs) as environmental-friendly solvents in chemical reactors and separation processes, the knowledge of their solubilities with water is essential. In the present work, mutual solubilities of 1500 ILs (50 cations, 30 anions) with water at 298.15 K were predicted by using the conductor-like screening model for real solvents (COSMO-RS) as a thermodynamic model. On the basis of the COSMO-RS calculations, the influence of the types of anion and cation, side chain modifications and substituent groups on the mutual solubility with water was extensively analyzed. The data obtained can be used for the prescreening of ILs as solvent candidates. Moreover, to understand the intrinsic solubility behavior in detail, different types of molecular interactions between ILs and water in solution were compared on the basis of the determination of multiple water-IL interaction energies from COSMO-RS computation. The results confirm that hydrogen bonding interactions between anions and water molecules have the dominant influence on the solubility. Finally, for the purpose of fast solubility estimation and solvent selection, COSMO-RS derived molecular descriptors which indicate the strength of anionic HB acceptors were calculated for typical anions and anion families. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25862985 [article] An overview of mutual solubility of ionic liquids and water predicted by COSMO - RS [texte imprimé] / Teng Zhou, Auteur ; Long Chen, Auteur ; Yinmei Ye, Auteur . - 2012 . - pp. 6256-6264. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 17 (Mai 2012) . - pp. 6256-6264 Mots-clés : Ionic  liquid  Solubility Résumé : To properly screen and use ionic liquids (ILs) as environmental-friendly solvents in chemical reactors and separation processes, the knowledge of their solubilities with water is essential. In the present work, mutual solubilities of 1500 ILs (50 cations, 30 anions) with water at 298.15 K were predicted by using the conductor-like screening model for real solvents (COSMO-RS) as a thermodynamic model. On the basis of the COSMO-RS calculations, the influence of the types of anion and cation, side chain modifications and substituent groups on the mutual solubility with water was extensively analyzed. The data obtained can be used for the prescreening of ILs as solvent candidates. Moreover, to understand the intrinsic solubility behavior in detail, different types of molecular interactions between ILs and water in solution were compared on the basis of the determination of multiple water-IL interaction energies from COSMO-RS computation. The results confirm that hydrogen bonding interactions between anions and water molecules have the dominant influence on the solubility. Finally, for the purpose of fast solubility estimation and solvent selection, COSMO-RS derived molecular descriptors which indicate the strength of anionic HB acceptors were calculated for typical anions and anion families. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25862985

Basic modeling and simulation tool for analysis of hydraulic transients in hydroelectric power plants / Hongqing Fang in IEEE transactions on energy conversion, Vol. 23 n°3 (Septembre 2008) 

Public ISBD [article]  in IEEE transactions on energy conversion > Vol. 23 n°3 (Septembre 2008) . - pp. 834 - 841 Titre : Basic modeling and simulation tool for analysis of hydraulic transients in hydroelectric power plants Type de document : texte imprimé Auteurs : Hongqing Fang, Auteur ; Long Chen, Auteur ; Dlakavu, N., Auteur Année de publication : 2008 Article en page(s) : pp. 834 - 841 Note générale : Energy conversion Langues : Anglais (eng) Mots-clés : Hydraulic  turbines;  hydroelectric  power  stations;  mathematics  computing;  three-term  control;  velocity  control Résumé : In this paper, the simulation system of a typical hydroelectric power plant was developed in a MATLAB/Simulink-based software environment, which has a high water head and a long penstock with upstream and downstream surge tanks and is equipped with a Francis turbine. With MATLAB/Simulink, the models of the proposed simulation system are all modularized and visualized, and can be reused easily. No complex codes have been programmed and the proposed simulation system adapts varieties of hydroelectric power plants. The nonlinear characteristics of hydraulic turbine and then inelastic water hammer effect were considered to calculate and simulate hydraulic transients. Moreover, the influences of different parameters, such as hydraulic turbine speed governor proportional-integral-derivative (PID) gains, pressure water supply system, as well as surge tanks, were analyzed for the dynamic performance of hydraulic turbine regulating system. The digital simulations of a sudden full load rejection for an actual hydroelectric power plant in China were performed, and the results indicate that the proposed MATLAB/Simulink-based hydroelectric power plant simulation system is accurate and effective enough to represent and simulate hydroelectric power plant's nonlinear dynamics as well as to design hydraulic turbine speed control system. The proposed simulation system has also been proved to be useful for preliminary designs or assessments of hydropower projects. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4548418&sortType%3Das [...] [article] Basic modeling and simulation tool for analysis of hydraulic transients in hydroelectric power plants [texte imprimé] / Hongqing Fang, Auteur ; Long Chen, Auteur ; Dlakavu, N., Auteur . - 2008 . - pp. 834 - 841. Energy conversion Langues : Anglais (eng) in IEEE transactions on energy conversion > Vol. 23 n°3 (Septembre 2008) . - pp. 834 - 841 Mots-clés : Hydraulic  turbines;  hydroelectric  power  stations;  mathematics  computing;  three-term  control;  velocity  control Résumé : In this paper, the simulation system of a typical hydroelectric power plant was developed in a MATLAB/Simulink-based software environment, which has a high water head and a long penstock with upstream and downstream surge tanks and is equipped with a Francis turbine. With MATLAB/Simulink, the models of the proposed simulation system are all modularized and visualized, and can be reused easily. No complex codes have been programmed and the proposed simulation system adapts varieties of hydroelectric power plants. The nonlinear characteristics of hydraulic turbine and then inelastic water hammer effect were considered to calculate and simulate hydraulic transients. Moreover, the influences of different parameters, such as hydraulic turbine speed governor proportional-integral-derivative (PID) gains, pressure water supply system, as well as surge tanks, were analyzed for the dynamic performance of hydraulic turbine regulating system. The digital simulations of a sudden full load rejection for an actual hydroelectric power plant in China were performed, and the results indicate that the proposed MATLAB/Simulink-based hydroelectric power plant simulation system is accurate and effective enough to represent and simulate hydroelectric power plant's nonlinear dynamics as well as to design hydraulic turbine speed control system. The proposed simulation system has also been proved to be useful for preliminary designs or assessments of hydropower projects. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4548418&sortType%3Das [...]

Decolorization of orange II in aqueous solution by an Fe(II)/sulfite system / Long Chen 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. 13632–13638 Titre : Decolorization of orange II in aqueous solution by an Fe(II)/sulfite system : Replacement of persulfate Type de document : texte imprimé Auteurs : Long Chen, Auteur ; Xinzi Peng, Auteur ; Jihao Liu, Auteur Année de publication : 2012 Article en page(s) : pp. 13632–13638 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Aqueous  solution  sulfite  system Résumé : A novel process for decolorizing dyes with sulfate radicals (SO4•–) using an Fe(II)/sulfite system is reported in this manuscript. The objective of this study was to investigate the conditions under which Fe(II) activates Na2SO3 to produce SO4•– and decolorize organic dyes. Orange II, Rhodamine B, Indigo Carmine, and Reactive Brilliant Blue X-BR could be efficiently decolorized using this novel system, which was compared with the Fe(II)/persulfate and Fenton (Fe(II)/H2O2) systems. The Fe(II)/sulfite system surpassed the other two in the decolorization of these dyes, and detailed mechanisms of the Fe(II)/sulfite system were researched. Primary radical identification through quenching experiments using tert-butyl alcohol and ethanol confirmed the existence of SO4•–, HO•, and SO5•–. A kinetic model was established for the halide ion effect, and kI–,SO4•– (3.2 × 1011 mol–1 L s–1) and RSO4•–f (10–4–10–3 mol L–1 s–1) were indirectly derived. In conclusion, the Fe(II)/sulfite system is a good candidate for use in detoxifying water contaminants. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3020389 [article] Decolorization of orange II in aqueous solution by an Fe(II)/sulfite system : Replacement of persulfate [texte imprimé] / Long Chen, Auteur ; Xinzi Peng, Auteur ; Jihao Liu, Auteur . - 2012 . - pp. 13632–13638. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 42 (Octobre 2012) . - pp. 13632–13638 Mots-clés : Aqueous  solution  sulfite  system Résumé : A novel process for decolorizing dyes with sulfate radicals (SO4•–) using an Fe(II)/sulfite system is reported in this manuscript. The objective of this study was to investigate the conditions under which Fe(II) activates Na2SO3 to produce SO4•– and decolorize organic dyes. Orange II, Rhodamine B, Indigo Carmine, and Reactive Brilliant Blue X-BR could be efficiently decolorized using this novel system, which was compared with the Fe(II)/persulfate and Fenton (Fe(II)/H2O2) systems. The Fe(II)/sulfite system surpassed the other two in the decolorization of these dyes, and detailed mechanisms of the Fe(II)/sulfite system were researched. Primary radical identification through quenching experiments using tert-butyl alcohol and ethanol confirmed the existence of SO4•–, HO•, and SO5•–. A kinetic model was established for the halide ion effect, and kI–,SO4•– (3.2 × 1011 mol–1 L s–1) and RSO4•–f (10–4–10–3 mol L–1 s–1) were indirectly derived. In conclusion, the Fe(II)/sulfite system is a good candidate for use in detoxifying water contaminants. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3020389

Dividend smoothing and predictability / Long Chen in Management science, Vol. 58 N° 10 (Octobre 2012) 

Public ISBD [article]  in Management science > Vol. 58 N° 10 (Octobre 2012) . - pp. 1834-1853 Titre : Dividend smoothing and predictability Type de document : texte imprimé Auteurs : Long Chen, Auteur ; Zhi Da, Auteur ; Richard Priestley, Auteur Année de publication : 2012 Article en page(s) : pp. 1834-1853 Note générale : Management Langues : Anglais (eng) Mots-clés : Dividend-price  ratio  Earning-price  ratio  Dividend  growth  Earnings  growth  Return  Predictability  Dividend  smoothing Résumé : The relative predictability of returns and dividends is a central issue because it forms the paradigm to interpret asset price variation. A little studied question is how dividend smoothing, as a choice of corporate policy, affects predictability. We show that even if dividends are supposed to be predictable without smoothing, dividend smoothing can bury this predictability. Because aggregate dividends are dramatically more smoothed in the postwar period than before, the lack of dividend growth predictability in the postwar period does not necessarily mean that there is no cash flow news in stock price variations; rather, a more plausible interpretation is that dividends are smoothed. Using two alternative measures that are less subject to dividend smoothing—net payout and earnings—we reach the consistent conclusion that cash flow news plays a more important role than discount rate news in price variations in the postwar period. ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/58/10/1834.abstract [article] Dividend smoothing and predictability [texte imprimé] / Long Chen, Auteur ; Zhi Da, Auteur ; Richard Priestley, Auteur . - 2012 . - pp. 1834-1853. Management Langues : Anglais (eng) in Management science > Vol. 58 N° 10 (Octobre 2012) . - pp. 1834-1853 Mots-clés : Dividend-price  ratio  Earning-price  ratio  Dividend  growth  Earnings  growth  Return  Predictability  Dividend  smoothing Résumé : The relative predictability of returns and dividends is a central issue because it forms the paradigm to interpret asset price variation. A little studied question is how dividend smoothing, as a choice of corporate policy, affects predictability. We show that even if dividends are supposed to be predictable without smoothing, dividend smoothing can bury this predictability. Because aggregate dividends are dramatically more smoothed in the postwar period than before, the lack of dividend growth predictability in the postwar period does not necessarily mean that there is no cash flow news in stock price variations; rather, a more plausible interpretation is that dividends are smoothed. Using two alternative measures that are less subject to dividend smoothing—net payout and earnings—we reach the consistent conclusion that cash flow news plays a more important role than discount rate news in price variations in the postwar period. ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/58/10/1834.abstract