16 results on '"Feng, Xiaojun"'
Search Results
2. Regulating labour dispatch in China: A cat-and-mouse game
- Author
-
Feng Xiaojun
- Subjects
General Arts and Humanities ,media_common.quotation_subject ,05 social sciences ,0211 other engineering and technologies ,0507 social and economic geography ,General Social Sciences ,021107 urban & regional planning ,02 engineering and technology ,050701 cultural studies ,New normal ,Precarity ,Optimism ,Countermovement ,Political economy ,Political science ,China ,Enforcement ,General Economics, Econometrics and Finance ,media_common - Abstract
This article suggests cautious optimism toward the prevailing Polanyian countermovement discourse by providing a timely and comprehensive examination of the enforcement of the labour dispatch regulation in China. Since the enactment of the regulation, some enterprises have narrowed the remuneration gap between agency workers and formal employees, while others have retained a large gap in overtime pay, bonuses, and welfare benefits between these two groups of workers. The regulation has reduced the number of agency workers, but has invoked the abuse of the more precarious ‘outsourced’ workers as well. The regulation has had little effect on limiting the use of agency labour to temporary, auxiliary, or substitute positions, raising the requirements of engaging in the labour dispatch business, or stabilizing the employment of agency workers. This article contributes to the extant literature on regulatory enforcement by examining the effects of non-standard employment regulation, highlighting the variance of labour law compliance among enterprises with different types of ownership, and demonstrating how China’s ongoing transformation from a planned to a market economy since the 1980s and from high growth to a new normal since 2010 has fundamentally constrained the full implementation of its labour protection regulation.
- Published
- 2018
3. The interaction mechanism of mechanical activated energetic composites
- Author
-
Zhao Juan, Xue Lexing, Xue-song Feng, Bo Feng, Tao Jun, Wang Xiaofeng, and Feng Xiaojun
- Subjects
Materials science ,010304 chemical physics ,Binding energy ,General Physics and Astronomy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Surfaces, Coatings and Films ,Mechanism (engineering) ,Molecular dynamics ,0103 physical sciences ,Ceramics and Composites ,Composite material ,0210 nano-technology ,Microscopic morphology - Abstract
Herein, in order to study the interaction mechanism of mechanical activated energetic composites, molecular dynamics simulation was carried out to calculate the binding energy and the interaction m...
- Published
- 2018
4. Manufacturing Conflict: The Experience of a World Factory in a Changing China
- Author
-
Feng Xiaojun
- Subjects
History ,Sociology and Political Science ,05 social sciences ,Geography, Planning and Development ,0507 social and economic geography ,Unrest ,050701 cultural studies ,0506 political science ,Management ,050602 political science & public administration ,Production (economics) ,Factory ,Business ,Economic system ,China - Abstract
This article explores the mechanism driving China’s soaring labor unrest from the perspective of management. It demonstrates how Foxconn adjusts in response to the dynamics of the global production network and China’s labor market, and how such practices are inextricably linked to growing workplace conflicts. Foxconn’s elementary management is characterized by coercion, which is reinforced by the management techniques it has forged as a contract manufacturer in the global supply chain facing the increasing costs of raw materials, labor, and so on. The widespread dissent generated in this process is aggravated by the changing composition and the worsening financial condition of its labor force—predominantly the new generation of migrant workers. Although Foxconn has attempted to develop consent on the shop floor, its efforts have largely failed because of the power asymmetry in the global electronics industry.
- Published
- 2017
5. When Proterozoic Crusts Became Thick: New Insights from Magma Petrology
- Author
-
Ganne, Jérôme, Feng, Xiaojun, McFarlane, Helen, Macouin, Mélina, Rousse, Sonia, Naba, Seta, Traoré, Abraham, Hodel, Florent, Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), School of Safety Engineering, China University of Mining and Technology, School of Earth, Atmosphere and Environment, Monash University, Monash University [Clayton], Université Joseph Ki-Zerbo [Ouagadougou] (UJZK), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
- Subjects
lcsh:Geology ,proterozoic ,statistical petrology ,[SDU]Sciences of the Universe [physics] ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,crustal thickness ,Physics::Space Physics ,lcsh:QE1-996.5 ,[SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,magma chemistry ,Astrophysics::Earth and Planetary Astrophysics ,Physics::Geophysics - Abstract
The Earth&rsquo, s continental crust represents the outermost envelope of the solid Earth, controlling exchanges within the geosphere and reflecting geodynamics processes. One of the fundamental issues of Earth Science aims to determine crustal thickness in past geodynamic environments in order to discuss the evolution of certain geodynamic processes through time. Despite presenting a continuing challenge, the evolution of crustal thickness during the last 3 billion years can be investigated using indirect clues yielded by the chemical signature of mafic magmas and associated ferromagnesian minerals (pyroxene, amphibole). Here, we present a new statistical assessment of a global database of magmatic and mineral chemical information. Analysis reveals the increasing occurrence of high-temperature pyroxenes and amphiboles growing in Ca-rich, Fe-poor magma since ~1 Ga, which contrasts with lower temperature conditions of minerals crystallization throughout the Meso- and Palaeoproterozoic times. This is interpreted to reflect temporal changes in the control of Earth&rsquo, s crust on mantle-derived magma composition, related to changes in lithospheric thickness and mantle secular cooling. We propose that thick existing crust is associated with deeper, hotter magmatic reservoirs, potentially elucidating the mineral chemistry and the contrasting iron content between primary and derivative mafic magmas. Based on both the chemical and mineral information of mafic magma, an integrated approach provides qualitative estimates of past crustal thickness and associated magmatic systems. Our findings indicate that the Proterozoic was characterized by thicker crustal sections (>, 40&ndash, 50 km) relative to the Phanerozoic and Archean (<, 35 km). This period of crustal thickening appears at the confluence of major changes on Earth, marked by the onset of mantle cooling and Plate Tectonics and the assembly of Columbia, the first supercontinent.
- Published
- 2018
6. A sandwich structured drug delivery composite membrane for improved recovery after spinal cord injury under longtime controlled release
- Author
-
Jiamin Wu, Gu Jun, Feng Xiaojun, Yue Xu, Xiaoli Song, Jiefeng Gao, and Hongxia Shao
- Subjects
Biocompatibility ,02 engineering and technology ,01 natural sciences ,Chitosan ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,0103 physical sciences ,medicine ,Humans ,Physical and Theoretical Chemistry ,Spinal cord injury ,Sandwich-structured composite ,Spinal Cord Injuries ,010304 chemical physics ,Mesenchymal Stem Cells ,Surfaces and Interfaces ,General Medicine ,021001 nanoscience & nanotechnology ,medicine.disease ,Controlled release ,Microspheres ,Membrane ,Nerve growth factor ,Spinal Cord ,chemistry ,Delayed-Action Preparations ,Drug delivery ,0210 nano-technology ,Biotechnology ,Biomedical engineering - Abstract
A sandwich structured composite membrane for longtime controlled release of nerve growth factor (NGF) to repair spinal cord injury (SCI) is prepared through electrospray. In this system, PLA film is used as the sealing layer to prevent drug diffusion and provide mechanical support, PLGA microspheres as the sandwich layer to load and controlled release NGF, and chitosan (CS) film as the planting layer to seed bone marrow mesenchymal stem cells (BMSCs). The composite membrane has good biocompatibility and can effectively promote PC-12 cells to differentiate into neurons. In addition, the composite membrane can be directly applied to the injured areas without further damage. The longtime sustained release of NGF guaranteed enough requirement time for SCI repair, which will decrease the administration frequency and improve patient compliance. The administration of BMSCs coupled with the sandwich composite membrane effectively relieves SCI, decreases cavity formation, enhances neuronal regeneration and tissue repair, as well as improves the recovery of locomotor functions. Overall, this present work provides a future perspective for the treatment of SCI by the NGF-loaded sandwich composite membrane with prolonged drug release function.
- Published
- 2021
7. Primary magmas and mantle temperatures through time
- Author
-
Ganne, Jérôme and Feng, Xiaojun
- Abstract
Chemical composition of mafic magmas is a critical indicator of physicochemical conditions, such as pressure, temperature, and fluid availability, accompanying melt production in the mantle and its evolution in the continental or oceanic lithosphere. Recovering this information has fundamental implications in constraining the thermal state of the mantle and the physics of mantle convection throughout the Earth's history. Here a statistical approach is applied to a geochemical database of about 22,000 samples from the mafic magma record. Potential temperatures (T-ps) of the mantle derived from this database, assuming melting by adiabatic decompression and a Ti-dependent (Fe2O3/TiO2 - 0.5) or constant redox condition (Fe2+/Sigma Fe= 0.9 or 0.8) in the magmatic source, are thought to be representative of different thermal "horizons' (or thermal heterogeneities) in the ambient mantle, ranging in depth from a shallow sublithospheric mantle (T-p minima) to a lower thermal boundary layer (T-p maxima). The difference of temperature (Delta T-p) observed between T-p maxima and minima did not change significantly with time (similar to 170 degrees C). Conversely, a progressive but limited cooling of similar to 150 degrees C is proposed since similar to 2.5 Gyr for the Earth's ambient mantle, which falls in the lower limit proposed by Herzberg et al. [ 2010] (similar to 15-250 degrees C hotter than today). Cooling of the ambient mantle after 2.5 Ga is preceded by a high-temperature plateau evolution and a transition from dominant plumes to a plate tectonics geodynamic regime, suggesting that subductions stabilized temperatures in the Archaean mantle that was in warming mode at that time.
- Published
- 2017
8. Numerical modelling of large-scale transcurrent faulting and compression effects - Examples from West Africa and New Zealand
- Author
-
Feng, Xiaojun, Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Université Toulouse 3 Paul Sabatier (UT3 Paul Sabatier), Mark Jessell, and Roland Martin
- Subjects
craton ouest-africain ,Failles décrochantes ,Numerical modelling ,Transcurrent faults ,Localisation de la déformation ,The West African Craton ,zones de failles alpines ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,Exhumation ,Modélisation numérique ,Localization of deformation ,The Alpine Fault zones - Abstract
The objective of this thesis is to explore the role shear zones play in localization of deformation and exhumation of the lower crust by using a series of 2D and 3D thermo-mechanical numerical models using the West African Craton (WAC) and the Alpine Fault zones as study areas. With respect to the localization of deformation in the upper crust, different orientations of a system of branched strike-slip faults were studied. Under compression boundary conditions, the results show that the internal fault zones as well as the host rocks in between the faults behave as relatively weaker domains than the external regions. Under simple shear boundary conditions, we explored the process of self-organization of the Australian-Pacific plate boundary fault in southern New Zealand. The models show that deformation is focused along narrow high-strain shear zones in the centre of the model when the softening coefficients are high, whereas the strain is more diffuse with many shear zones spread over the model and possibly some high-strain shear zones focused near one border at lower softening coefficients.Regarding the role pre-existing faults and basins play in exhumation of the partially molten lower crust, 2D and 3D models with different boundary conditions were tested (including extension, transtension and compression).- Under extension, in the Eastern and Western parts of the high grade rock corridors in NW Ghana, partially molten rocks exhumed from the lower into middle-upper crustal levels are interpreted to have been dominantly facilitated by the km-scale high-strain corridors. In the central part of the Bole-Bulenga domain, the high grade rocks are interpreted to have been exhumed as a result of a coupling between two mechanisms: (1) the concentration of partially molten rocks between the Jirapa and Bole-Nangodi faults increases due to the reduction in space from north to south; (2) the concentration of lower partially molten rocks in the central part, as a result of inherited orthogonal (E-W) faults. - Under transtension, in the Sefwi terrane of SW Ghana, the Kukuom-Juaboso domain (KJD) composed of up to amphibolite-migmatite facies could result from the concentration of upwelling partially molten rocks in the relay zone between the Ketesso and Kenyase shear zones during transtension. The two shear zones probably underwent two main stages for growth and maturation from the D1 to D2 deformation phases. The regional exhumation of the high grade rocks in the Sefwi terrane probably occurred within a duration of less than 5 Ma.- Under compression, the role of volcano-sedimentary basin on spatial-temporal evolution of the lower crust exhumation was tested. The models suggest that a series of sheet-like granitoids possibly derived from either subducted mélanges, lower crust and/or mantle melting accumulated at depths of the subcontinental mantle would channel along diapirs before feeding the upper crust. When the granitoids arrive at the solidified lids of the diapirs, they would favour migrating horizontally and intruding into the upper crust through weakening zones between the diapirs. This model also suggests an asymmetry of structures between the upper and middle-lower crust, with the dome-like granitoids overlying high-grade sedimentary synforms and high-grade diapirs underlying low-grade greenstone belts.; L'objectif de cette thèse est d'étudier le rôle joué par les zones de cisaillement sur la localisation de la déformation et de l'exhumation de la croûte inférieure grâce à une série de modèles numériques thermomécaniques 2D et 3D que nous avons appliqué à deux cas d’étude: le craton ouest-africain (WAC) et les zones de failles alpines en Nouvelle Zélande. En ce qui concerne la localisation de la déformation dans la croûte supérieure, différentes orientations pour un système de décrochement en ramification ont été testées. Sous un régime compressif, les résultats montrent que les zones de failles internes, ainsi que les unités de roches présentes entre ces failles réagissent de façon plus fragile que les unités rocheuses présentes à l’extérieur de ces domaines. Pour le cas d’un régime de déformation en cisaillement simple, nous avons exploré le processus de réorganisation qui s’est produit aux limites de deux plaques (i.e. Australie et Pacifique) au sud de la Nouvelle-Zélande. Les modèles montrent que la déformation se concentre le long des zones de cisaillement étroites, situées au centre du modèle, lorsque les coefficients d’amollissement sont élevés. Inversement, la contrainte cisaillante ressort de façon plus diffuse à travers le modèle lorsque les coefficients d’amollissement sont faibles. Les cisaillements s’expriment alors sur l’ensemble du modèle bien que les taux de cisaillement restent les plus élevés sur les bordures du modèle.Afin de tester l’impact de failles héritées et de bassins préexistants sur l’exhumation de la croûte inférieure, des modèles 2D et 3D ont été testés avec différentes conditions aux limites (traduisant extension, transtension et compression).- En contexte extensif, dans les portions Est et Ouest des corridors fortement métamorphisés du Nord-Ouest Ghana, des roches partiellement fondues, issues de la croûte inférieure, ont pu être exhumées au sein des croûtes moyenne à supérieure. Dans la partie centrale du domaine de Bolé-Bulenga, des roches très métamorphisées ont été exhumées grâce au couplage de deux mécanismes: (1) la concentration de roches partiellement fondues entre les failles de Jirapa et de Bolé-Nangodi; ces failles convergent vers le sud, induisant un rétrécissement de l’espace disponible pour accueillir ce matériel fondu; (2) la concentration de roches partiellement fondues dans la partie centrale, induite par un jeu de failles héritées d’orientation Est-Ouest.- En contexte de transtension, dans le terrane de Sefwi au Sud-Ouest Ghana, le domaine de Kukuom-Juaboso (KJD), composé majoritairement par des roches à faciès de type amphibolite à migmatitique, semble s’être mis en place sous forme d’intrusions au sein d’une zone relais située entre les zones de cisaillements de Kenyase et de Ketésso. Ces deux zones de cisaillement sont marquées par un stade de croissance puis de maturation qui semblent être reliés aux phases de déformation D1 puis D2 reconnues régionalement. L’exhumation régionale des roches très métamorphisées dans le terrane de Sefwi s’est probablement produite en moins de 5 Ma.- En régime compressif, l’impact joué par les bassins volcano-sédimentaires sur le processus d’exhumation de la croûte inférieure a été testé numériquement. Les modèles suggèrent que de multiples injections de magmas granitoïdiques, dérivant soit de matériaux subductés, soit d’une fusion de produits crustaux ou de matériel mantellique accumulés en profondeur, ont pu être canalisées au sein de diapirs avant de venir nourrir la croûte supérieure. Ce modèle suggère également une asymétrie des structures entre la croûte supérieure d’une part, et la croûte inférieure à moyenne d’autre part: i.e. (i) les bassins de roches vertes faiblement métamorphisés de la croûte supérieure reposent sur les diapirs métamorphisés et (ii) les bassins de roches vertes très métamorphisés constituent le soubassement des dômes granitoïdiques de la croûte supérieure.
- Published
- 2016
9. Modélisation numérique des failles décrochantes et des effets de compression à grande échelle - Cas d'étude en Afrique de l'Ouest et Nouvelle Zélande
- Author
-
Feng, Xiaojun, Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Université Toulouse 3 Paul Sabatier (UT3 Paul Sabatier), Mark Jessell, Roland Martin, Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
- Subjects
craton ouest-africain ,Failles décrochantes ,Numerical modelling ,Transcurrent faults ,Localisation de la déformation ,The West African Craton ,zones de failles alpines ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,Exhumation ,Modélisation numérique ,Localization of deformation ,The Alpine Fault zones - Abstract
The objective of this thesis is to explore the role shear zones play in localization of deformation and exhumation of the lower crust by using a series of 2D and 3D thermo-mechanical numerical models using the West African Craton (WAC) and the Alpine Fault zones as study areas. With respect to the localization of deformation in the upper crust, different orientations of a system of branched strike-slip faults were studied. Under compression boundary conditions, the results show that the internal fault zones as well as the host rocks in between the faults behave as relatively weaker domains than the external regions. Under simple shear boundary conditions, we explored the process of self-organization of the Australian-Pacific plate boundary fault in southern New Zealand. The models show that deformation is focused along narrow high-strain shear zones in the centre of the model when the softening coefficients are high, whereas the strain is more diffuse with many shear zones spread over the model and possibly some high-strain shear zones focused near one border at lower softening coefficients.Regarding the role pre-existing faults and basins play in exhumation of the partially molten lower crust, 2D and 3D models with different boundary conditions were tested (including extension, transtension and compression).- Under extension, in the Eastern and Western parts of the high grade rock corridors in NW Ghana, partially molten rocks exhumed from the lower into middle-upper crustal levels are interpreted to have been dominantly facilitated by the km-scale high-strain corridors. In the central part of the Bole-Bulenga domain, the high grade rocks are interpreted to have been exhumed as a result of a coupling between two mechanisms: (1) the concentration of partially molten rocks between the Jirapa and Bole-Nangodi faults increases due to the reduction in space from north to south; (2) the concentration of lower partially molten rocks in the central part, as a result of inherited orthogonal (E-W) faults. - Under transtension, in the Sefwi terrane of SW Ghana, the Kukuom-Juaboso domain (KJD) composed of up to amphibolite-migmatite facies could result from the concentration of upwelling partially molten rocks in the relay zone between the Ketesso and Kenyase shear zones during transtension. The two shear zones probably underwent two main stages for growth and maturation from the D1 to D2 deformation phases. The regional exhumation of the high grade rocks in the Sefwi terrane probably occurred within a duration of less than 5 Ma.- Under compression, the role of volcano-sedimentary basin on spatial-temporal evolution of the lower crust exhumation was tested. The models suggest that a series of sheet-like granitoids possibly derived from either subducted mélanges, lower crust and/or mantle melting accumulated at depths of the subcontinental mantle would channel along diapirs before feeding the upper crust. When the granitoids arrive at the solidified lids of the diapirs, they would favour migrating horizontally and intruding into the upper crust through weakening zones between the diapirs. This model also suggests an asymmetry of structures between the upper and middle-lower crust, with the dome-like granitoids overlying high-grade sedimentary synforms and high-grade diapirs underlying low-grade greenstone belts.; L'objectif de cette thèse est d'étudier le rôle joué par les zones de cisaillement sur la localisation de la déformation et de l'exhumation de la croûte inférieure grâce à une série de modèles numériques thermomécaniques 2D et 3D que nous avons appliqué à deux cas d’étude: le craton ouest-africain (WAC) et les zones de failles alpines en Nouvelle Zélande. En ce qui concerne la localisation de la déformation dans la croûte supérieure, différentes orientations pour un système de décrochement en ramification ont été testées. Sous un régime compressif, les résultats montrent que les zones de failles internes, ainsi que les unités de roches présentes entre ces failles réagissent de façon plus fragile que les unités rocheuses présentes à l’extérieur de ces domaines. Pour le cas d’un régime de déformation en cisaillement simple, nous avons exploré le processus de réorganisation qui s’est produit aux limites de deux plaques (i.e. Australie et Pacifique) au sud de la Nouvelle-Zélande. Les modèles montrent que la déformation se concentre le long des zones de cisaillement étroites, situées au centre du modèle, lorsque les coefficients d’amollissement sont élevés. Inversement, la contrainte cisaillante ressort de façon plus diffuse à travers le modèle lorsque les coefficients d’amollissement sont faibles. Les cisaillements s’expriment alors sur l’ensemble du modèle bien que les taux de cisaillement restent les plus élevés sur les bordures du modèle.Afin de tester l’impact de failles héritées et de bassins préexistants sur l’exhumation de la croûte inférieure, des modèles 2D et 3D ont été testés avec différentes conditions aux limites (traduisant extension, transtension et compression).- En contexte extensif, dans les portions Est et Ouest des corridors fortement métamorphisés du Nord-Ouest Ghana, des roches partiellement fondues, issues de la croûte inférieure, ont pu être exhumées au sein des croûtes moyenne à supérieure. Dans la partie centrale du domaine de Bolé-Bulenga, des roches très métamorphisées ont été exhumées grâce au couplage de deux mécanismes: (1) la concentration de roches partiellement fondues entre les failles de Jirapa et de Bolé-Nangodi; ces failles convergent vers le sud, induisant un rétrécissement de l’espace disponible pour accueillir ce matériel fondu; (2) la concentration de roches partiellement fondues dans la partie centrale, induite par un jeu de failles héritées d’orientation Est-Ouest.- En contexte de transtension, dans le terrane de Sefwi au Sud-Ouest Ghana, le domaine de Kukuom-Juaboso (KJD), composé majoritairement par des roches à faciès de type amphibolite à migmatitique, semble s’être mis en place sous forme d’intrusions au sein d’une zone relais située entre les zones de cisaillements de Kenyase et de Ketésso. Ces deux zones de cisaillement sont marquées par un stade de croissance puis de maturation qui semblent être reliés aux phases de déformation D1 puis D2 reconnues régionalement. L’exhumation régionale des roches très métamorphisées dans le terrane de Sefwi s’est probablement produite en moins de 5 Ma.- En régime compressif, l’impact joué par les bassins volcano-sédimentaires sur le processus d’exhumation de la croûte inférieure a été testé numériquement. Les modèles suggèrent que de multiples injections de magmas granitoïdiques, dérivant soit de matériaux subductés, soit d’une fusion de produits crustaux ou de matériel mantellique accumulés en profondeur, ont pu être canalisées au sein de diapirs avant de venir nourrir la croûte supérieure. Ce modèle suggère également une asymétrie des structures entre la croûte supérieure d’une part, et la croûte inférieure à moyenne d’autre part: i.e. (i) les bassins de roches vertes faiblement métamorphisés de la croûte supérieure reposent sur les diapirs métamorphisés et (ii) les bassins de roches vertes très métamorphisés constituent le soubassement des dômes granitoïdiques de la croûte supérieure.
- Published
- 2016
10. Effect of strain-weakening on Oligocene-Miocene self-organization of the Australian-Pacific plate boundary fault in southern New Zealand : insights from numerical modelling
- Author
-
Feng, Xiaojun, Jessell, M. W., Amponsah, P. O., Martin, R., Ganne, Jérôme, Liu, D. Q., and Batt, G. E.
- Subjects
Alpine Fault ,Numerical modelling ,Strain-weakening ,Fault - Abstract
Tectonic inheritance acquired from past geological events can control the formation of new plate boundaries. The aim of this paper is to explore the role of inherited NE and NW trending fabrics and their rheological influence on the propagation of Oligocene-Miocene strike-slip faulting that matured to become the Australian-Pacific plate boundary fault in southern New Zealand. Strain weakening plays a significant role in controlling the formation, growth and evolution of strain localization. In this study, three-dimensional thermo-mechanical models have been used to explore the effect of strain weakening on the Oligocene-Miocene self-organization of strain localization. Strain weakening is simulated through decreasing either the coefficient of friction of upper crust, its cohesion, or the rheological viscosity contrast between the inherited structures and their surrounding wall rocks. Viscosity contrast is obtained by varying the viscosity of inherited structures. Softening coefficient (a) is a measure of strain weakening. Our experiments robustly demonstrate that a primary boundary shear zone becomes mature quicker when softening coefficients are increased. Deformation is focused along narrow high-strain shear zones in the centre of the model when the softening coefficients are high, whereas the strain is more diffuse with many shear zones spread over the model and possibly some high-strain shear zones focused near one border at lower softening coefficients. Varying the viscosity contrast has less effect on the distribution of maximum finite strain. Under simple-shear boundary conditions, NW trending inherited structures make a major contribution to forming early zones of highly focused strain, up to a shear strain of about gamma = 3.7. During this process, most NE-trending structures move and rotate passively, accommodate less strain, or even be abandoned through time.
- Published
- 2016
11. The dynamic impact of rock burst induced by the fracture of the thick and hard key stratum
- Author
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Chen Yu, Wang Enyuan, Wei Ming-yao, Cao Xinqi, Shen Rongxi, and Feng Xiaojun
- Subjects
Mechanical load ,key stratum ,Compaction ,General Medicine ,rock burst ,Structural dynamics ,dynamic loading ,Rock burst ,Overburden ,Dynamic loading ,Fracture (geology) ,energy constant ,Geotechnical engineering ,Geology ,Engineering(all) ,Stratum - Abstract
To reveal the dynamic impact of rock bursting induced by the thick and hard roof of gravel as key stratum fractured, based on the key strata and rock control theories, combined with the mechanical load-based dynamic loading with the Law of Conservation of Energy in a system, this paper analysed the static stability and the processing of energy conversion within the system when the key stratum was fracturing. And the key stratum dynamic model of fracturing was established. The results indicate that large amounts of strain energy would be forced into the rock during the process as the key stratum fractures and becomes unstable. The greater the dynamic load factor is, the more elastic energy is forced into the lower rock strata of the key stratum, and the more obvious the dynamic impact of the lower rock strata would be. The size of the dynamic load factor relates to the aspect ratio of key rock masses, the thickness of the overburden, the mining height, the height of the fragmentized rock at the bottom of key stratum and the compaction coefficient of the fragmentized rock under the static during loading conditions. According to the calculation of actual work, the results are consistent with the field tests approximately. The results can provide references to similar conditions.
- Published
- 2011
- Full Text
- View/download PDF
12. The advantages of PD1 activating chimeric receptor (PD1-ACR) engineered lymphocytes for PDL1+ cancer therapy
- Author
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Tang, Xiaolong, Li, Qingguo, Zhu, Yongqiang, Zheng, Donghui, Dai, Jingjing, Ni, Wenxuan, Wei, Jia, Xue, Yubao, Chen, Ke, Hou, Wei, Zhang, Chao, Feng, Xiaojun, and Liang, Yong
- Subjects
Original Article - Abstract
Tumors exploit immunoregulatory checkpoints to attenuate T cell responses as a means of circumventing immunologic rejection. By activating the inhibitory costimulatory pathway of Programmed Death 1 (PD1)/PDL1 which provides tumor cells an escape mechanism from immune surveillance, Programmed Death Ligand1 (PDL1)(+) tumors hamper activated tumor-specific T cell functions and render them functionally exhausted. To overcome the inhibitory costimulatory effects of PDL1 on the adoptively transferred T cells, we sought to convert PD1 to a T cell costimulatory receptor by exchanging its transmembrane and cytoplasmic tail with CD28 and 4-1BB signaling domains (PD1-CD28-4-1BB, PD1-ACR), anticipating the genetically modified effector T lymphocytes expressing PD1-ACR would exhibit enhanced functional attributes. And the results showed that PD1-ACR expressed T cells retained the ability to bind PDL1, resulting in T cell activation as evidenced by the elevated activity of phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt), the augmentation of cytokine secretion and the increased proliferative capacity. Moreover, when systemically administered in the mouse model of glioblastoma metastases, PD1-ACR T cells localized at the area of U87 invasive tumor, which results in suppressed tumor growth and enhanced survival of mice with established U87 glioblastoma. Together, these data demonstrated that PD1-ACR has a high potential to serve as a novel strategy to overcome PDL1 mediated immunosuppression of T cells for cancer therapy.
- Published
- 2015
13. Advances in coupling microfluidic chips to mass spectrometry
- Author
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Feng, Xiaojun, Liu, Bi-Feng, Li, Jianjun, and Liu, Xin
- Abstract
Microfluidic technology has shown advantages of low sample consumption, reduced analysis time, high throughput, and potential for integration and automation. Coupling microfluidic chips to mass spectrometry (Chip-MS) can greatly improve the overall analytical performance of MS-based approaches and expand their potential applications. In this article, we review the advances of Chip-MS in the past decade, covering innovations in microchip fabrication, microchips coupled to electrospray ionization (ESI)-MS and matrix-assisted laser desorption/ionization (MALDI)-MS. Development of integrated microfluidic systems for automated MS analysis will be further documented, as well as recent applications of Chip-MS in proteomics, metabolomics, cell analysis, and clinical diagnosis.
- Published
- 2014
14. Genetic markers in blue crabs (Callinectes sapidus) II: Complete mitochondrial genome sequence and characterization of genetic variation
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Place, Allen R., Feng, Xiaojun, Steven, Colin R., Fourcade, H. Matthew, and Boore, Jeffrey L.
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mitochondrial genome blue crab nucleotide variation long PCR shotgun sequencing gene rearrangement - Published
- 2004
15. Outburst prevention and control technology of thin coal zone in island coal face with potential outburst
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Feng Xiaojun, Shen Rongxi, Wang Enyuan, Xu Wenquan, and HU Shaobin
- Subjects
Engineering ,Injury control ,Drill ,outburst coal seam ,business.industry ,Accident prevention ,Coal mining ,technology, industry, and agriculture ,Poison control ,General Medicine ,respiratory system ,complex mixtures ,thin coal zone ,Geological structure ,respiratory tract diseases ,Mining engineering ,effect check ,Forensic engineering ,otorhinolaryngologic diseases ,Coal ,loosening blast ,island coal face ,Problems in coal mining ,business ,Engineering(all) - Abstract
As for coal seam feature, geological structure and mining face stress concentration, the thin coal zone in island coal face with potential outburst is liable to induce dynamic disaster, such as coal and gas outburst, rockburst. It can improve the safety level and resource recovery ratio to research the outburst control technology of thin coal zone in island coal face.11061 mining face of Liangbei mine is an island coal face, and the coal seam has outburst danger. When 11061 coal face exposed the thin coal zone unexpectedly, the strata behaviours were so serious that the coal face was forced to stop mining. Based on the distribution characteristics and stress regularity of the thin coal zone, the comprehensive outburst prevention and control technology which consists of pressure-releasing drill, loosening blast, discharging drill and effect check has been found and used in the thin coal zone. The results has proved that the comprehensive outburst prevention and control technology is effective to remove the outburst danger of the thin coal zone in 11061mining face, and the comprehensive technology can help to mine 11061 coal face continuously in spite of the thin coal zone, which has brought successful engineering experience and distinct economic benefit.
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16. Theoretical investigation on intermolecular interactions between the ingredients TNT and RDX of composition B
- Author
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Niu Xiaoqing, Jian-Guo Zhang, Feng Xiaojun, Chen Pengwan, Zhang Tonglai, Wang Shiying, Zhang Shaowen, Zhou Zunning, and Yang Li
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