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Analysis of seismic activity in the crust from earthquake relocation in the central Tien Shan / Yi Xu in Bulletin of the seismological society of America, Vol. 96 N° 2 (Avril 2006) 

Public ISBD [article]  in Bulletin of the seismological society of America > Vol. 96 N° 2 (Avril 2006) . - 737-744 p. Titre : Analysis of seismic activity in the crust from earthquake relocation in the central Tien Shan Titre original : Analyse d'activité séismique dans la croûte de la relocalisation de tremblement de terre dans Tien Shan central Type de document : texte imprimé Auteurs : Yi Xu, Auteur ; Steve W. Roecker, Auteur ; Bing Wei, Auteur ; Wenlai Zhang, Auteur ; Ruoping Wei, Auteur Article en page(s) : 737-744 p. Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Séisme  Réseau  séismique Index. décimale : 551.2 Résumé : Using P- and S-wave arrivals from local earthquakes recorded by a temporary broadband seismic network (GHENGIS) and a Kyrgyzstan broadband seismic network (KNET), we determined the source parameters of 1938 earthquakes occurring from 1997 to 1998 in the central Tien Shan and adjacent areas, based on one- dimensional and three-dimensional velocity models. The results indicate that seismic activity is not restricted to only central Tien Shan but also penetrates into the edges of the Kazakh platform and the Tarim basin to the north and south, respectively. It implies that most range-bounding faults in the central Tien Shan are active and they play a significant role in the tectonic activity of the mountain belt. However, seismic activity of the Talas-Fergana fault in the study area is different; its central segment seems more active than its eastern segment. We infer that this part of the fault may be activated by neighboring faults, whereas its eastern segment could be temporally locked. The earthquakes at the depths of 30–40 km beneath the east-central Tien Shan reveal an interaction between the upper and mid-lower crust. This suggests that brittle failure is possible to greater depth within the crust. Another possibility is that the seismic activity in the mid-lower crust is affected by a positive buoyancy force created by mantle upwelling of this area. These observations indicate that dynamic processes such as small-scale mantle convection or mantle upwelling, which resulted in lithospheric thinning or removal, still occur beneath the central Tien Shan. Des arrivées en utilisant de p et de S vague à partir des tremblements de terre locaux enregistrés par un réseau séismique à bande large provisoire (GHENGIS) et un réseau séismique à bande large de Kyrgyzstan (KNET), nous avons déterminé les paramètres de source de 1938 tremblements de terre se produisant à partir de 1997 à 1998 dans Tien Shan central et les secteurs adjacents, basés sur les modèles unidimensionnels et tridimensionnels de vitesse. Les résultats indiquent que l'activité séismique n'est pas limitée seulement à Tien Shan central mais pénètre également dans les bords de la plateforme kazakh et du bassin de Tarim au nord et aux sud, respectivement. Il implique que la plupart des défauts de bondissement de gamme dans Tien Shan central sont en activité et ils jouent un rôle significatif dans l'activité tectonique de la ceinture de montagne. Cependant, l'activité séismique du défaut de Talas Ferghana dans le secteur d'étude est différente ; son segment central semble plus actif que son segment oriental. Nous impliquons que la présente partie du défaut peut être activée par les défauts voisins, tandis que son segment oriental pourrait être temporellement fermé à clef. Les tremblements de terre aux profondeurs de 30-40 kilomètres sous Tien Shan central est indiquent une interaction entre la croûte inférieure supérieure et mi. Ceci suggère que la rupture fragile soit possible à une plus grande profondeur dans la croûte. Une autre possibilité est que l'activité séismique dans la mi croûte inférieure est affectée par une force positive de flottabilité créée par la remontée de manteau de ce secteur. Ces observations indiquent que les processus dynamiques tels que la petite échelle enveloppent la convection ou enveloppent la remontée, qui a eue comme conséquence amincir ou déplacement lithosphérique, se produisent toujours sous Tien Shan central. DEWEY : 551.2 ISSN : 0037-1106 En ligne : xuyi@mail.iggcas.ac.cn [article] Analysis of seismic activity in the crust from earthquake relocation in the central Tien Shan = Analyse d'activité séismique dans la croûte de la relocalisation de tremblement de terre dans Tien Shan central [texte imprimé] / Yi Xu, Auteur ; Steve W. Roecker, Auteur ; Bing Wei, Auteur ; Wenlai Zhang, Auteur ; Ruoping Wei, Auteur . - 737-744 p. Génie Civil Langues : Anglais (eng) in Bulletin of the seismological society of America > Vol. 96 N° 2 (Avril 2006) . - 737-744 p. Mots-clés : Séisme  Réseau  séismique Index. décimale : 551.2 Résumé : Using P- and S-wave arrivals from local earthquakes recorded by a temporary broadband seismic network (GHENGIS) and a Kyrgyzstan broadband seismic network (KNET), we determined the source parameters of 1938 earthquakes occurring from 1997 to 1998 in the central Tien Shan and adjacent areas, based on one- dimensional and three-dimensional velocity models. The results indicate that seismic activity is not restricted to only central Tien Shan but also penetrates into the edges of the Kazakh platform and the Tarim basin to the north and south, respectively. It implies that most range-bounding faults in the central Tien Shan are active and they play a significant role in the tectonic activity of the mountain belt. However, seismic activity of the Talas-Fergana fault in the study area is different; its central segment seems more active than its eastern segment. We infer that this part of the fault may be activated by neighboring faults, whereas its eastern segment could be temporally locked. The earthquakes at the depths of 30–40 km beneath the east-central Tien Shan reveal an interaction between the upper and mid-lower crust. This suggests that brittle failure is possible to greater depth within the crust. Another possibility is that the seismic activity in the mid-lower crust is affected by a positive buoyancy force created by mantle upwelling of this area. These observations indicate that dynamic processes such as small-scale mantle convection or mantle upwelling, which resulted in lithospheric thinning or removal, still occur beneath the central Tien Shan. Des arrivées en utilisant de p et de S vague à partir des tremblements de terre locaux enregistrés par un réseau séismique à bande large provisoire (GHENGIS) et un réseau séismique à bande large de Kyrgyzstan (KNET), nous avons déterminé les paramètres de source de 1938 tremblements de terre se produisant à partir de 1997 à 1998 dans Tien Shan central et les secteurs adjacents, basés sur les modèles unidimensionnels et tridimensionnels de vitesse. Les résultats indiquent que l'activité séismique n'est pas limitée seulement à Tien Shan central mais pénètre également dans les bords de la plateforme kazakh et du bassin de Tarim au nord et aux sud, respectivement. Il implique que la plupart des défauts de bondissement de gamme dans Tien Shan central sont en activité et ils jouent un rôle significatif dans l'activité tectonique de la ceinture de montagne. Cependant, l'activité séismique du défaut de Talas Ferghana dans le secteur d'étude est différente ; son segment central semble plus actif que son segment oriental. Nous impliquons que la présente partie du défaut peut être activée par les défauts voisins, tandis que son segment oriental pourrait être temporellement fermé à clef. Les tremblements de terre aux profondeurs de 30-40 kilomètres sous Tien Shan central est indiquent une interaction entre la croûte inférieure supérieure et mi. Ceci suggère que la rupture fragile soit possible à une plus grande profondeur dans la croûte. Une autre possibilité est que l'activité séismique dans la mi croûte inférieure est affectée par une force positive de flottabilité créée par la remontée de manteau de ce secteur. Ces observations indiquent que les processus dynamiques tels que la petite échelle enveloppent la convection ou enveloppent la remontée, qui a eue comme conséquence amincir ou déplacement lithosphérique, se produisent toujours sous Tien Shan central. DEWEY : 551.2 ISSN : 0037-1106 En ligne : xuyi@mail.iggcas.ac.cn

Effect of polymer granules on the electrostatic behavior in gas−solid fluidized beds / Xianbo Yu in Industrial & engineering chemistry research, Vol. 49 N° 1 (Janvier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 1 (Janvier 2010) . - pp. 132–139 Titre : Effect of polymer granules on the electrostatic behavior in gas−solid fluidized beds Type de document : texte imprimé Auteurs : Xianbo Yu, Auteur ; Wei Li, Auteur ; Yi Xu, Auteur Année de publication : 2010 Article en page(s) : pp. 132–139 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Effect--Polymer  Granules--Electrostatic--Gas−Solid--Fluidized  Beds Résumé : Granules polymers electrostatic behavior in a fluidized bed can be complicated by the differences in catalyst residue and surface properties among them. Electrically charged particles cling together in large aggregates and adhere to the wall of the apparatus. Polymer particles with the same chemical composition but different sizes would have their own special contributions to the generation of static charges. It is improtant to understand polymer particles role on electrostatic charge generation and dissipation. Experiments are carried out in a gas−solid fluidized bed with nitrogen as the fluidization gas to determine the relationship between the electrostatic charge level and the size of the polyethylene granule. By measuring the electrostatic potentials at different bed axial heights, it is found that the electric field inside the bed is significantly influenced by the size, weight fractions, and catalyst residue of added granular polyethylene. Consequently, an impact factor of granules (Fb) is proposed to study the influence of particle size and the weight percent of the residual catalyst to the electrostatic potentials. And it is found that the greater the degree of fineness of the granules, the more percentage of the residual catalyst in the particles, which results in the stronger affect on the electrostatic behavior in the fluidized bed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017077 [article] Effect of polymer granules on the electrostatic behavior in gas−solid fluidized beds [texte imprimé] / Xianbo Yu, Auteur ; Wei Li, Auteur ; Yi Xu, Auteur . - 2010 . - pp. 132–139. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 1 (Janvier 2010) . - pp. 132–139 Mots-clés : Effect--Polymer  Granules--Electrostatic--Gas−Solid--Fluidized  Beds Résumé : Granules polymers electrostatic behavior in a fluidized bed can be complicated by the differences in catalyst residue and surface properties among them. Electrically charged particles cling together in large aggregates and adhere to the wall of the apparatus. Polymer particles with the same chemical composition but different sizes would have their own special contributions to the generation of static charges. It is improtant to understand polymer particles role on electrostatic charge generation and dissipation. Experiments are carried out in a gas−solid fluidized bed with nitrogen as the fluidization gas to determine the relationship between the electrostatic charge level and the size of the polyethylene granule. By measuring the electrostatic potentials at different bed axial heights, it is found that the electric field inside the bed is significantly influenced by the size, weight fractions, and catalyst residue of added granular polyethylene. Consequently, an impact factor of granules (Fb) is proposed to study the influence of particle size and the weight percent of the residual catalyst to the electrostatic potentials. And it is found that the greater the degree of fineness of the granules, the more percentage of the residual catalyst in the particles, which results in the stronger affect on the electrostatic behavior in the fluidized bed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017077

Optimal and competitive assortments with endogenous pricing under hierarchical consumer choice models / Gürhan A. Kök in Management science, Vol. 57 N° 9 (Septembre 2011) 

Public ISBD [article]  in Management science > Vol. 57 N° 9 (Septembre 2011) . - pp. 1546-1563 Titre : Optimal and competitive assortments with endogenous pricing under hierarchical consumer choice models Type de document : texte imprimé Auteurs : Gürhan A. Kök, Auteur ; Yi Xu, Auteur Année de publication : 2011 Article en page(s) : pp. 1546-1563 Note générale : Management Langues : Anglais (eng) Mots-clés : Assortment  planning  Product  variety  Category  management  Pricing  Inventory  costs  Nested  multinomial  logit  model Index. décimale : 658 Organisation des entreprises. Techniques du commerce Résumé : This paper studies assortment planning and pricing for a product category with heterogeneous product types from two brands. We model consumer choice using the nested multinomial logit framework with two different hierarchical structures: a brand-primary model in which consumers choose a brand first, then a product type in the chosen brand, and a type-primary model in which consumers choose a product type first, then a brand within that product type. We consider a centralized regime that finds the optimal solution for the whole category and a decentralized regime that finds a competitive equilibrium between two brands. We find that optimal and competitive assortments and prices have quite distinctive properties across different models. Specifically, with the brand-primary model, both the optimal and the competitive assortments for each brand consist of the most popular product types from the brand. With the type-primary choice model, the optimal and the competitive assortments for each brand may not always consist of the most popular product types of the brand. Instead, the overall assortment in the category consists of a set of most popular product types. The price of a product under the centralized regime can be characterized by a sum of a markup that is constant across all products and brands, its procurement cost, and its marginal operational cost, implying a lower price for more popular products. The markup may be different for each brand and product type under the decentralized regime, implying a higher price for brands with a larger market share. These properties of the assortments and prices can be used as effective guidelines for managers to identify and price the best assortments and to rule out nonoptimal assortments. Our results suggest that to offer the right set of products and prices, category and/or brand managers should create an assortment planning process that is aligned with the hierarchical choice process consumers commonly follow to make purchasing decisions. DEWEY : 658 ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/57/9.toc [article] Optimal and competitive assortments with endogenous pricing under hierarchical consumer choice models [texte imprimé] / Gürhan A. Kök, Auteur ; Yi Xu, Auteur . - 2011 . - pp. 1546-1563. Management Langues : Anglais (eng) in Management science > Vol. 57 N° 9 (Septembre 2011) . - pp. 1546-1563 Mots-clés : Assortment  planning  Product  variety  Category  management  Pricing  Inventory  costs  Nested  multinomial  logit  model Index. décimale : 658 Organisation des entreprises. Techniques du commerce Résumé : This paper studies assortment planning and pricing for a product category with heterogeneous product types from two brands. We model consumer choice using the nested multinomial logit framework with two different hierarchical structures: a brand-primary model in which consumers choose a brand first, then a product type in the chosen brand, and a type-primary model in which consumers choose a product type first, then a brand within that product type. We consider a centralized regime that finds the optimal solution for the whole category and a decentralized regime that finds a competitive equilibrium between two brands. We find that optimal and competitive assortments and prices have quite distinctive properties across different models. Specifically, with the brand-primary model, both the optimal and the competitive assortments for each brand consist of the most popular product types from the brand. With the type-primary choice model, the optimal and the competitive assortments for each brand may not always consist of the most popular product types of the brand. Instead, the overall assortment in the category consists of a set of most popular product types. The price of a product under the centralized regime can be characterized by a sum of a markup that is constant across all products and brands, its procurement cost, and its marginal operational cost, implying a lower price for more popular products. The markup may be different for each brand and product type under the decentralized regime, implying a higher price for brands with a larger market share. These properties of the assortments and prices can be used as effective guidelines for managers to identify and price the best assortments and to rule out nonoptimal assortments. Our results suggest that to offer the right set of products and prices, category and/or brand managers should create an assortment planning process that is aligned with the hierarchical choice process consumers commonly follow to make purchasing decisions. DEWEY : 658 ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/57/9.toc

The impact of royalty contract revision in a multistage strategic R&D alliance / Wenqiang Xiao in Management science, Vol. 58 N° 12 (Décembre 2012) 

Public ISBD [article]  in Management science > Vol. 58 N° 12 (Décembre 2012) . - pp. 2251-2271 Titre : The impact of royalty contract revision in a multistage strategic R&D alliance Type de document : texte imprimé Auteurs : Wenqiang Xiao, Auteur ; Yi Xu, Auteur Année de publication : 2013 Article en page(s) : pp. 2251-2271 Note générale : Management Langues : Anglais (eng) Mots-clés : Research  and  development  Royalty  contract  Renegotiation  Incentives  R&D  alliance Résumé : This paper investigates the impact of royalty revision on incentives and profits in a two-stage (research and development (R&D) stage and marketing stage) alliance with a marketer and an innovator. The marketer offers royalty contracts to the innovator. We find that the potential for royalty revision leads to more severe distortions in the optimal initial royalty contracts offered by the marketer. We show that if the innovator plays a significant role in the marketing stage, the marketer should offer a low royalty rate initially and then revise the royalty rate up later. Otherwise, she should do the opposite. We identify two major effects of royalty revision. First, royalty revision provides the marketer with a flexibility to dynamically adjust royalty rates across the two stages of the alliance to better align the innovator's incentives. This incentive-realigning effect improves the marketer's profit. Second, royalty revision makes it harder for the marketer to obtain private information from the innovator, because the innovator worries that the marketer will take advantage of the information to revise the initial contract to a more favorable one to herself later. This information-revealing effect hurts the marketer's profit. We characterize in what kind of alliances marketers would benefit the most from royalty revision so that managers should clearly establish the expectation for royalty revision, and in what kind of alliances markerters would not benefit from royalty revision so that managers should commit not to revise the initial royalty contract. With royalty contracts that are contingent on the R&D outcome of the R&D stage, we find that contingent contract structure could be either substitutable (by fully capturing the incentive re-aligning effect) or complementary (by weakening the information revealing effect) to royalty revision, depending on whether the innovator plays a significant role in the marketing stage. Managers may need to use a contingent contract (if possible) either to replace or with royalty revision accordingly to improve profits. ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/58/12/2251.abstract [article] The impact of royalty contract revision in a multistage strategic R&D alliance [texte imprimé] / Wenqiang Xiao, Auteur ; Yi Xu, Auteur . - 2013 . - pp. 2251-2271. Management Langues : Anglais (eng) in Management science > Vol. 58 N° 12 (Décembre 2012) . - pp. 2251-2271 Mots-clés : Research  and  development  Royalty  contract  Renegotiation  Incentives  R&D  alliance Résumé : This paper investigates the impact of royalty revision on incentives and profits in a two-stage (research and development (R&D) stage and marketing stage) alliance with a marketer and an innovator. The marketer offers royalty contracts to the innovator. We find that the potential for royalty revision leads to more severe distortions in the optimal initial royalty contracts offered by the marketer. We show that if the innovator plays a significant role in the marketing stage, the marketer should offer a low royalty rate initially and then revise the royalty rate up later. Otherwise, she should do the opposite. We identify two major effects of royalty revision. First, royalty revision provides the marketer with a flexibility to dynamically adjust royalty rates across the two stages of the alliance to better align the innovator's incentives. This incentive-realigning effect improves the marketer's profit. Second, royalty revision makes it harder for the marketer to obtain private information from the innovator, because the innovator worries that the marketer will take advantage of the information to revise the initial contract to a more favorable one to herself later. This information-revealing effect hurts the marketer's profit. We characterize in what kind of alliances marketers would benefit the most from royalty revision so that managers should clearly establish the expectation for royalty revision, and in what kind of alliances markerters would not benefit from royalty revision so that managers should commit not to revise the initial royalty contract. With royalty contracts that are contingent on the R&D outcome of the R&D stage, we find that contingent contract structure could be either substitutable (by fully capturing the incentive re-aligning effect) or complementary (by weakening the information revealing effect) to royalty revision, depending on whether the innovator plays a significant role in the marketing stage. Managers may need to use a contingent contract (if possible) either to replace or with royalty revision accordingly to improve profits. ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/58/12/2251.abstract