Une expérience d'enseignement- apprentissage raisonné des caractères

International audienceDe nouvelles méthodes d'enseignement de la langue et de l'écriture chinoises sont apparues depuis quinze ans en France. Elles rompent avec l'approche didactique dominante de l'enseignement dispersé du vocabulaire au fil des textes et n'imposent plus aux apprenants d'avoir à apprendre à écrire tout ce qu'ils apprennent à dire. Certaines d'entre elles tirent parti de cette toute nouvelle liberté didactique pour sélectionner avec soin les caractères à enseigner de façon à optimiser leur mémorisation par les apprenants. Ce sont ce qu'on peut appeler des « méthodes d'enseignement apprentissage raisonné des caractères », qui sont à la fois respectueuses de la logique graphique et de la cohérence du chinois écrit et également respectueuse du processus cognitif de mémorisation

漫谈对外"理性识字法"的构造

International audienceThis paper presents the primary results of research on Chinese characters teaching of Chinese as maternal language and Chinese as a foreign language. In China, the teaching of characters has a long history and has accumulated precious experiences. The author especially studied the method of teaching characters in the Mass Education movement (pingmin jiaoyu) of the years 1920-1927, and the “regrouped character teaching” (jizhong shizi) created in 1958 for primary schools. He insists on the answers these methods have given to two main questions: 1. How many characters must a student learn in order to be able to read? 2. How is it possible to teach characters in a “reasoned ”way, respecting the rules of the graphic composition of the characters and using the most efficient way for a student to memorize them?“理性识字法”就是一种既体现汉语汉字的特点，又符合学习者的学习策略以及认知规律的识字方法。本论文谈到怎么能构造这类的方法。作者引用一些中国母语的识字法经验，尤其是第二十世纪20年代扫盲教育使用的一些识字课本以及目前还行之有效的小学集中识字方法

Le débat sur la place attribuée aux caractères dans l'enseignement du chinois langue étrangère et l'émergence d'une école française de la disjonction oral/écrit

International audienc

漫谈对外"理性识字法"的构造

International audienceThis paper presents the primary results of research on Chinese characters teaching of Chinese as maternal language and Chinese as a foreign language. In China, the teaching of characters has a long history and has accumulated precious experiences. The author especially studied the method of teaching characters in the Mass Education movement (pingmin jiaoyu) of the years 1920-1927, and the “regrouped character teaching” (jizhong shizi) created in 1958 for primary schools. He insists on the answers these methods have given to two main questions: 1. How many characters must a student learn in order to be able to read? 2. How is it possible to teach characters in a “reasoned ”way, respecting the rules of the graphic composition of the characters and using the most efficient way for a student to memorize them?“理性识字法”就是一种既体现汉语汉字的特点，又符合学习者的学习策略以及认知规律的识字方法。本论文谈到怎么能构造这类的方法。作者引用一些中国母语的识字法经验，尤其是第二十世纪20年代扫盲教育使用的一些识字课本以及目前还行之有效的小学集中识字方法

3D geological & geophysical modelling of Plateau de Sault (Eastern Pyrenees) for good water management

International audienceBetter constrain the geological geometries in 3 dimensions aids to improve subsequent hydrological modeling and simulations. The project "Plateau de Sault" (Eastern Pyrenees) aims to provide a better estimate and management of water resources of the region. The water flow occurs mostly underground via significant karst networks in a complex tectonic framework. Thus, a 3D geological model was built, as a prerequisite for hydrological studies, with the 3D GeoModeller software (©BRGM-Intrepid Geophysics) which is unique in interpolating complex geology using a potential field method. The construction of this 3D geological model has 3 main objectives: improve regional geology's knowledge, propose geometries for limestone urgonian bars and define hypothetical connections between different aquifers. Structures at depth have been constrained by direct calculation and gravimetric inversion of the geological model thanks to newly acquired gravimetric data (around 250 stations) and densities of formations established in laboratory from 52 rocks sampled in the field. This study demonstrates the importance of integrative tools as 3D geological modeling for good water management

Improving our knowledge on the hydro-chemo-mechanical behaviour of fault zones in the context of CO2 geological storage

Fault systems can play a significant role regarding several risk issues related to CO2-injection-induced mechanical perturbations: fluid flow enhancement or compartmentalization within the reservoir, loss of integrity of the reservoir-caprock systems, potential triggering of seismicity and generation of new leakage pathways or permeability barriers. Several methods exist to model hydro-mechanical behaviour of fault zones. A first "conventional" approach aims at evaluating the fault response by directly post-processing the results of the large-scale coupled hydro-mechanical simulations. This consists of: estimating the changes of the effective stress field in the reservoir-caprock system during CO2 injection; computing changes of shear and normal stresses acting on the fault plane; comparing them to a fault reactivation criterion. However, this approach does not account for the effects of the presence of the fault on the stress and pressure field in the surrounding rock matrix. More sophisticated (and physically more realistic) modeling strategies have been proposed, which explicitly integrate the fault zone as a distinct element in the large-scale simulation, i.e. by representing it as a linear discontinuity with various hydraulic and mechanical properties. From a CO2 storage perspective, such a model still remains limited regarding two issues: 1. Faults are complex and heterogeneous geological systems, which do not correspond to discrete surfaces as already postulated by many authors. A fault zone is composed of an inner core made of fine material, often impermeable, and where slip is concentrated. It is surrounded by an outer damage zone that often acts as a hydraulic pathway, because of the presence of a fracture network, whose characteristics (fractures' orientation, connectivity, lengths, density, number of fractures' families, etc.) depend on the distance to the core; 2. Chemical interactions (dissolution and precipitation processes, chemically-induced weakening, etc.) between CO2-enriched brine and the minerals constituting the fault zone. can affect the mechanical and transport properties of the faulted/fractured system. In particular, chemo-mechanical processes can either stabilize the system if the compaction rate is increased or destabilize it if new micro-fractures are created. The FISIC project intends to overcome those limitations by accurately modelling the hydro-chemo-mechanical (HCM) complexity of a fault zone. The main goal is to provide appropriate theoretical and numerical models for accurate evaluation of fault stability in the context of CO2 geological storage, i.e. improving the stability analysis of a fault both undertaking pressure increase and alteration due to the presence of an acidic fluid. Four research questions are addressed and the progress regarding each of them is presented: 1. How to represent a fault zone in a tectonic setting, which has a priori been selected far from major potentially seismically-active faults, i.e. a moderate-to-low-deformed setting; 2. What are the fractures' organization within the damage zones of faults, i.e. their spatial distribution? 3. What are the dominant chemo-mechanical processes resulting from aqueous CO2 in fractured/faulted systems? 4. How to integrate (numerically) the hydro-chemo-mechanical (HCM) behaviour of fault zones in large-scale (reservoir or basin-scale) simulations? Regarding the first and second question, a geostatistical approach is adopted based on observations of fault structures at the Cirque de Navacelles. This site, located in the late Jurassic platform carbonates of Languedoc (southern France), can be considered a good analogue for CO2 storage reservoir. The third question is addressed at laboratory scale focusing on the CO2(aqueous)-induced effect on: i. the slow growth of cracks (subcritical fracturing) and their healing; ii. the degradation of mechanical properties such as fracture toughness or shear strength. Finally, the fourth question is numerically addressed by relying on: i. advanced meshing tools developed for converting complex geometries to finite element models; ii. analysis of fracture propagation condition within multiphase fractured porous media; iii. the rheological behavior derived from the experimental study

Bridging static and dynamic modeling: an application to high energy geothermal reservoir modeling

International audienceWhen mass and energy transfers are involved, bridging static and dynamic modeling in a seamless way is a milestone to build reliable conceptual models of the subsurface in order to efficiently exploit its resources or use it as a storage space (energy, gas, waste…). Our purpose here is to be able to build interactive conceptual models of high energy geothermal reservoirs. As these reservoirs are always located in complex geological settings (faults and fractures are ubiquitous features) and involve the circulation of hot brines over a wide range of thermodynamical parameters, we must be able:#1 to quickly build structural models involving geological bodies of any shape and with the occurrence of discontinuities,#2 to produce conformable meshes of such models,#3 to perform multiphase thermo-hydraulic simulations with phase change on these meshes without numerical artefacts.Over the years, iso-potential surface mapping has proved an efficient framework to achieve goal #1 and it is now implemented in several commercial softwares (e.g. GeoModeller). Yet, when it comes to goal #2 the implicit nature of surfaces make volumic meshing a non-trivial task. We recently used the Computational Geometry Algorithms Library (CGAL) to build conformal simplicial (tetrahedral) meshes that exactly match any geological 3D object and its boundaries or internal 2D features such as fault surfaces. A crucial issue of this process is to provide the mesher with sharp features of dimension 1 (surface intersections) to avoid local over-refinement (or even crash of the algorithm). Finally, to reach goal #3 we used the Vertex Approximate Gradient finite volume scheme which has been adapted to model mass and energy over any polyhedral meshes with the possibility to take into account objects of codimension 1 such as fault surfaces which may act as corridors for fluid flows.We think that the proposed workflow and computing tools can be easily adapted to any other thematic field than geothermal reservoir modeling both for engineering purposes and the simulation of geological processes over very large timescales