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Aggregation-resistant superparamagnetic noncovalent hybrid multilayer hollow microcapsules in high ionic strength media / Peng Liu in Industrial & engineering chemistry research, Vol. 51 N° 43 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 43 (Octobre 2012) . - pp. 13875-13881 Titre : Aggregation-resistant superparamagnetic noncovalent hybrid multilayer hollow microcapsules in high ionic strength media Type de document : texte imprimé Auteurs : Peng Liu, Auteur ; Xiaorui Li, Auteur ; Bin Mu, Auteur Année de publication : 2013 Article en page(s) : pp. 13875-13881 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Ionic  strength  Microcapsule  Multiple  layer  Aggregation Résumé : In order to avoid the aggregation and/or fusion of the polyelectrolyte multilayer hollow microcapsules self-assembled via the noncovalent bonds, superparamagnetic polyelectrolyte hybrid hollow microcapsules surface-modified with polyethylene glycol (PEG) brushes were designed and fabricated. After the layer-by-layer (LbL) self-assembly of chitosan (CS) and citric acid-modified magnetic nanoparticles (Fe3O4―CA) as the polycation and the hybrid anion on the polystyrene sulfonate microsphere (PSS) templates, respectively, the aldehyde group terminated polyethylene glycol-4000 (APEG) was grafted onto the surface of the superparamagnetic polyelectrolyte hybrid multilayer coated template microspheres via the nucleophilic addition between the aldehyde groups of APEG and the amino groups of CS. Then, the modified superparamagnetic polyelectrolyte hybrid hollow microcapsules were obtained after the templates were removed by dialysis. It was found that the surface PEGylation could prevent aggregation among the hollow microcapsules in the media with high salt concentration by dynamic light scattering (DLS), besides the increase in biocompatibility. The technique developed is expected to realize the application of the polyelectrolyte multilayer hollow microcapsules in real physiological environments. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26593312 [article] Aggregation-resistant superparamagnetic noncovalent hybrid multilayer hollow microcapsules in high ionic strength media [texte imprimé] / Peng Liu, Auteur ; Xiaorui Li, Auteur ; Bin Mu, Auteur . - 2013 . - pp. 13875-13881. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 43 (Octobre 2012) . - pp. 13875-13881 Mots-clés : Ionic  strength  Microcapsule  Multiple  layer  Aggregation Résumé : In order to avoid the aggregation and/or fusion of the polyelectrolyte multilayer hollow microcapsules self-assembled via the noncovalent bonds, superparamagnetic polyelectrolyte hybrid hollow microcapsules surface-modified with polyethylene glycol (PEG) brushes were designed and fabricated. After the layer-by-layer (LbL) self-assembly of chitosan (CS) and citric acid-modified magnetic nanoparticles (Fe3O4―CA) as the polycation and the hybrid anion on the polystyrene sulfonate microsphere (PSS) templates, respectively, the aldehyde group terminated polyethylene glycol-4000 (APEG) was grafted onto the surface of the superparamagnetic polyelectrolyte hybrid multilayer coated template microspheres via the nucleophilic addition between the aldehyde groups of APEG and the amino groups of CS. Then, the modified superparamagnetic polyelectrolyte hybrid hollow microcapsules were obtained after the templates were removed by dialysis. It was found that the surface PEGylation could prevent aggregation among the hollow microcapsules in the media with high salt concentration by dynamic light scattering (DLS), besides the increase in biocompatibility. The technique developed is expected to realize the application of the polyelectrolyte multilayer hollow microcapsules in real physiological environments. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26593312

Chitosan/functionalized multiwalled carbon nanotubes multilayer hollow microspheres prepared via layer-by-layer assembly technique / Chao Yang in Industrial & engineering chemistry research, Vol. 51 N° 41 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 41 (Octobre 2012) . - pp. 13346-13353 Titre : Chitosan/functionalized multiwalled carbon nanotubes multilayer hollow microspheres prepared via layer-by-layer assembly technique Type de document : texte imprimé Auteurs : Chao Yang, Auteur ; Peng Liu, Auteur Année de publication : 2012 Article en page(s) : pp. 13346-13353 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Microsphere  Multiple  layer Résumé : Novel multilayer hollow microspheres were fabricated via the layer-by-layer (LBL) assembly technique by the electrostatic interaction between the polycation chitosan (CHI) and the anion carboxyl-functionalized multiwalled carbon nanotubes (f-MWNTs) on sacrificial polystyrene sulfonate (PSS) microsphere templates. The successful stepwise growth of the CHI/f-MWNTs multilayers in different pH media was compared by zeta potential measurement and scanning electron microscopy (SEM) analysis. The morphologies of the hollow microspheres were characterized by transmission electron microscopy (TEM) and SEM. The swelling and collapse of the hollow microspheres occurred during the template removal by dissolution and the drying process. It was found that more f-MWNTs had been deposited onto the surface of the PSS microspheres at pH 3 than at pH 5, confirmed by SEM and thermogravimetric analysis (TGA). Furthermore, this result is consistent with the differences of the electrical conductivities of the hollow microspheres obtained from the different pH media. It is also found that in the etching process, the different etching reagents, such as DMF and toluene, obviously affected the electrical conductivity of the final hollow microspheres. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26493629 [article] Chitosan/functionalized multiwalled carbon nanotubes multilayer hollow microspheres prepared via layer-by-layer assembly technique [texte imprimé] / Chao Yang, Auteur ; Peng Liu, Auteur . - 2012 . - pp. 13346-13353. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 41 (Octobre 2012) . - pp. 13346-13353 Mots-clés : Microsphere  Multiple  layer Résumé : Novel multilayer hollow microspheres were fabricated via the layer-by-layer (LBL) assembly technique by the electrostatic interaction between the polycation chitosan (CHI) and the anion carboxyl-functionalized multiwalled carbon nanotubes (f-MWNTs) on sacrificial polystyrene sulfonate (PSS) microsphere templates. The successful stepwise growth of the CHI/f-MWNTs multilayers in different pH media was compared by zeta potential measurement and scanning electron microscopy (SEM) analysis. The morphologies of the hollow microspheres were characterized by transmission electron microscopy (TEM) and SEM. The swelling and collapse of the hollow microspheres occurred during the template removal by dissolution and the drying process. It was found that more f-MWNTs had been deposited onto the surface of the PSS microspheres at pH 3 than at pH 5, confirmed by SEM and thermogravimetric analysis (TGA). Furthermore, this result is consistent with the differences of the electrical conductivities of the hollow microspheres obtained from the different pH media. It is also found that in the etching process, the different etching reagents, such as DMF and toluene, obviously affected the electrical conductivity of the final hollow microspheres. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26493629

Facile approach for superparamagnetic CNT - Fe3O4 / polystyrene tricomponent nanocomposite via synergetic dispersion / Wu Zhong in Industrial & engineering chemistry research, Vol. 51 N° 37 (Septembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 37 (Septembre 2012) . - pp. 12017–12024 Titre : Facile approach for superparamagnetic CNT - Fe3O4 / polystyrene tricomponent nanocomposite via synergetic dispersion Type de document : texte imprimé Auteurs : Wu Zhong, Auteur ; Peng Liu, Auteur ; Zhaobin Tang, Auteur Année de publication : 2012 Article en page(s) : pp. 12017–12024 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanocomposite  Synergetic  dispersion Résumé : A facile one-pot in-situ radical bulk polymerization strategy was developed for preparation of the superparamagnetic multiwalled carbon nanotubes-Fe3O4/polystyrene (CNT-Fe3O4/PS) tricomponent nanocomposite by the synergetic dispersion strategy via the multiwalled carbon nanotubes (CNT) immobilized Fe3O4 nanoparticles (CNT-Fe3O4) with oleic acid (OA) as surface modifier. Compared with the tricomponent nanocomposite prepared with the multiwalled carbon nanotubes and Fe3O4 nanoparticles added separately, immobilization of Fe3O4 nanoparticles on multiwalled carbon nanotubes could avoid efficiently aggregation of the Fe3O4 nanoparticles in polymer matrices. OA molecules adsorb onto the surfaces of the Fe3O4 nanoparticles immobilized on the multiwalled carbon nanotubes, improving efficiently the dispersibility of the multiwalled carbon nanotubes in styrene, which resulted in the well-dispersed CNT-Fe3O4/PS tricomponent nanocomposite. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300891h [article] Facile approach for superparamagnetic CNT - Fe3O4 / polystyrene tricomponent nanocomposite via synergetic dispersion [texte imprimé] / Wu Zhong, Auteur ; Peng Liu, Auteur ; Zhaobin Tang, Auteur . - 2012 . - pp. 12017–12024. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 37 (Septembre 2012) . - pp. 12017–12024 Mots-clés : Nanocomposite  Synergetic  dispersion Résumé : A facile one-pot in-situ radical bulk polymerization strategy was developed for preparation of the superparamagnetic multiwalled carbon nanotubes-Fe3O4/polystyrene (CNT-Fe3O4/PS) tricomponent nanocomposite by the synergetic dispersion strategy via the multiwalled carbon nanotubes (CNT) immobilized Fe3O4 nanoparticles (CNT-Fe3O4) with oleic acid (OA) as surface modifier. Compared with the tricomponent nanocomposite prepared with the multiwalled carbon nanotubes and Fe3O4 nanoparticles added separately, immobilization of Fe3O4 nanoparticles on multiwalled carbon nanotubes could avoid efficiently aggregation of the Fe3O4 nanoparticles in polymer matrices. OA molecules adsorb onto the surfaces of the Fe3O4 nanoparticles immobilized on the multiwalled carbon nanotubes, improving efficiently the dispersibility of the multiwalled carbon nanotubes in styrene, which resulted in the well-dispersed CNT-Fe3O4/PS tricomponent nanocomposite. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300891h

Rational herding in microloan markets / Juanjuan Zhang in Management science, Vol. 58 N° 5 (Mai 2012) 

Public ISBD [article]  in Management science > Vol. 58 N° 5 (Mai 2012) . - pp. 892-912 Titre : Rational herding in microloan markets Type de document : texte imprimé Auteurs : Juanjuan Zhang, Auteur ; Peng Liu, Auteur Année de publication : 2012 Article en page(s) : pp. 892-912 Note générale : Management Langues : Anglais (eng) Mots-clés : Rational  herding  Observational  learning  Bayesian  inference  Microloan  markets  Peer-to-peer  lending  Prosper.com Résumé : Microloan markets allow individual borrowers to raise funding from multiple individual lenders. We use a unique panel data set that tracks the funding dynamics of borrower listings on Prosper.com, the largest microloan market in the United States. We find evidence of rational herding among lenders. Well-funded borrower listings tend to attract more funding after we control for unobserved listing heterogeneity and payoff externalities. Moreover, instead of passively mimicking their peers (irrational herding), lenders engage in active observational learning (rational herding); they infer the creditworthiness of borrowers by observing peer lending decisions and use publicly observable borrower characteristics to moderate their inferences. Counterintuitively, obvious defects (e.g., poor credit grades) amplify a listing's herding momentum, as lenders infer superior creditworthiness to justify the herd. Similarly, favorable borrower characteristics (e.g., friend endorsements) weaken the herding effect, as lenders attribute herding to these observable merits. Follow-up analysis shows that rational herding beats irrational herding in predicting loan performance. DEWEY : 658 ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/58/5/892.abstract [article] Rational herding in microloan markets [texte imprimé] / Juanjuan Zhang, Auteur ; Peng Liu, Auteur . - 2012 . - pp. 892-912. Management Langues : Anglais (eng) in Management science > Vol. 58 N° 5 (Mai 2012) . - pp. 892-912 Mots-clés : Rational  herding  Observational  learning  Bayesian  inference  Microloan  markets  Peer-to-peer  lending  Prosper.com Résumé : Microloan markets allow individual borrowers to raise funding from multiple individual lenders. We use a unique panel data set that tracks the funding dynamics of borrower listings on Prosper.com, the largest microloan market in the United States. We find evidence of rational herding among lenders. Well-funded borrower listings tend to attract more funding after we control for unobserved listing heterogeneity and payoff externalities. Moreover, instead of passively mimicking their peers (irrational herding), lenders engage in active observational learning (rational herding); they infer the creditworthiness of borrowers by observing peer lending decisions and use publicly observable borrower characteristics to moderate their inferences. Counterintuitively, obvious defects (e.g., poor credit grades) amplify a listing's herding momentum, as lenders infer superior creditworthiness to justify the herd. Similarly, favorable borrower characteristics (e.g., friend endorsements) weaken the herding effect, as lenders attribute herding to these observable merits. Follow-up analysis shows that rational herding beats irrational herding in predicting loan performance. DEWEY : 658 ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/58/5/892.abstract

Regulation of Catalytic Reaction via Vapor-Phase Condensation. 2. / Si-Cao Wu in Industrial & engineering chemistry research, Vol. 51 N° 26 (Juillet 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8742–8747 Titre : Regulation of Catalytic Reaction via Vapor-Phase Condensation. 2. : Operational Realization in a Two-Stage Reactor Type de document : texte imprimé Auteurs : Si-Cao Wu, Auteur ; Zhen-Min Cheng, Auteur ; Peng Liu, Auteur Année de publication : 2012 Article en page(s) : pp. 8742–8747 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Regulation  catalytic  reaction  Vapor  phase Résumé : A two-stage reactor composed of a slurry bubble column and a fixed bed was proposed. The slurry column, installed with a radio frequency conductance liquid level controller, was considered not only as a preliminary reactor for the vaporization of the liquid reactants, but also as a protector to prevent liquid flooding in the fixed bed. Preliminary experiments were carried out to investigate the effects of different operating factors on the reactor performance, and the results showed that even under the optimal condition the benzene concentration should be kept at a low level of 21.9% to avoid high temperature rise. Therefore, side stream injection of cyclohexane into the fixed bed was proposed, and benzene conversion of 99.82% was reached even at a much higher concentration of 32.8%. To verify whether capillary condensation inside the catalyst particle in the fixed bed would exist in the presence of coolant injection, a criterion was proposed which is based on the understanding that once vapor condensation is occurring it will lead to multiplicity in reaction rate, which will consequently result in hysteresis in temperature profile under adiabatic condition. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2019036 [article] Regulation of Catalytic Reaction via Vapor-Phase Condensation. 2. : Operational Realization in a Two-Stage Reactor [texte imprimé] / Si-Cao Wu, Auteur ; Zhen-Min Cheng, Auteur ; Peng Liu, Auteur . - 2012 . - pp. 8742–8747. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8742–8747 Mots-clés : Regulation  catalytic  reaction  Vapor  phase Résumé : A two-stage reactor composed of a slurry bubble column and a fixed bed was proposed. The slurry column, installed with a radio frequency conductance liquid level controller, was considered not only as a preliminary reactor for the vaporization of the liquid reactants, but also as a protector to prevent liquid flooding in the fixed bed. Preliminary experiments were carried out to investigate the effects of different operating factors on the reactor performance, and the results showed that even under the optimal condition the benzene concentration should be kept at a low level of 21.9% to avoid high temperature rise. Therefore, side stream injection of cyclohexane into the fixed bed was proposed, and benzene conversion of 99.82% was reached even at a much higher concentration of 32.8%. To verify whether capillary condensation inside the catalyst particle in the fixed bed would exist in the presence of coolant injection, a criterion was proposed which is based on the understanding that once vapor condensation is occurring it will lead to multiplicity in reaction rate, which will consequently result in hysteresis in temperature profile under adiabatic condition. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2019036

Water-dispersed conductive polypyrroles doped with lignosulfonate and the weak temperature dependence of electrical conductivity / Chao Yang in Industrial & engineering chemistry research, Vol. 48 N° 21 (Novembre 2009) 

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