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A NEW EXPLICIT SIMULATION FOR MOULD FILLING WITH HIGH VISCOUS FEEDSTOCK

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Acta Mechanica Solida Sinica 2004年第4期17卷 347-352页

作者： Cheng Zhiqiang Barriere Thierry Liu Baosheng Gelin jean.claude Department of Applied Mechanics Southwest Jiaotong UniversityChengdu 610031China LMARC University of Franche-Comte and CNRS24 Chemin de l’′epitapheBesancon 25000France

In the simulation of the metal injection moulding (MIM), the behaviours of feedstock are much di?erent from which of the polymer injection. It is a mixture of the metallic powder in high concentration and some plastic binder. The advance in simulation of the mould ?lling with such high viscous feedstock is featured by the development of a fully explicit vectorial algorithm. On the basis of previous explicit software realized by the authors, the new algorithm avoids the global solution for pressure ?elds and the use of MINI elements to improve its e?ciency. Except for the operations at element level, neither global solution nor the construction of global matrix is required in simulation. A special strategy is used to regulate the incompressibility condition in ?lled domain at each time step. In case of the MIM problems, this method provides a fast way to simulate the ?lling processes. The computational cost is about linearly proportional to the degree of freedom number. Moreover, this vectorial algorithm can be easily parallelized for high performance computation with multi-clusters. The comparison of numerical results with previous simulations on 3D cases proves the validity and e?ciency of new algorithm.

关键词： mould filling high viscosity explicit simulation vectorial algorithm

The ecology of sexual dimorphism in size and shape of the freshwater blenny Salaria fluviatilis

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Current Zoology 2018年第2期64卷 183-191页

作者： Martin LAPORTE Patrick BERREBI Julien claude Dolors VINYOLES Quim Pou-RoVIRA jean.claude RAYMOND Pierre MAGNAN lnstitut des Sciences de I'Evolution de Montpellier (ISEM) UMR 5554 UM2-CNRS-IRD Universite de Montpellier II CC065 Place E. Bataillon Montpellier Cedex 534095 France Departement de Biologie Institut de Biologie Integrative et des Systemes (IBIS) Universite Laval Quebec Quebec City Canada G1V 0A6 Department of Evolutionary Biology Ecology and Environmental Sciences Faculty of Biology University of Barcelona Avda. Diagonal 643 Barcelona 08028 Spain Sorello estudis al medi aquatic Placa St. Pere 15 Baixos 17007 Girona Spain Office National de I'Eau et des Milieux Aquatiques (0NEMA) Unite Specialisee Milieux Lacustres Pisciculture de Rives 13 Quai de Rives Thonon-les-Bains 74200 France Centre de recherche sur les interactions bassins versants-ecosystemes aquatiques (RIVE) Universite du Quebec a Trois-Rivieres C. P. 500 Trois-Rivieres Quebec City Canada G9A 5H7

Sexual selection is considered the major cause of sexual dimorphism, but recent observations suggest that natural selection may play a more important role in the evolution of sex differentiation than previously recognized. Therefore, studying the trade-offs between natural selection and sexual selection is crucial to a better understanding of the ecology underlying the evolution of sexual dimorphism. The freshwater blenny Salaria fluviatilis, a fish inhabiting lakes and rivers around the Mediterranean Sea, displays strong sexual dimorphism in size, shape, and behavior （i.e., larger body and head size for males and higher swimming requirements for females during the reproductive period）. We tested for differences in sexual dimorphism in size and shape between the populations from lake and river habitats with the goal of identifying the trade-offs between natural and sexual se- lection that underlie variations in sexual dimorphism in this species. Our results show i） differences in sexual size dimorphism （SSizeD） in accordance to Rensch＇s rule （i.e., larger individuals in rivers associated with higher SSizeD）, and ii） a decrease in shape differentiation between males and fe- males in lake populations. Together, this suggests that the different environmental conditions between lake and river habitats （e.g., resource limitations, predation pressure, water velocity） affect the relative importance of sexual selection in the display of sexual dimorphism within the species. This study highlights the importance of considering the environmental conditions to which populations are exposed to better understand the ecology underlying the evolution of sexual dimorphism.

关键词： evolutionary ecology geometric morphometrics phenotype-environment interaction Rensch's rule sexual dimorphism.

An octree-based proxy for collision detection in large-scale particle systems

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Science China(Information Sciences) 2013年第1期56卷 55-64页

作者： FAN WenShan WANG Bin PAUL jean.claude SUN JiaGuang School of Software Tsinghua University Beijing Aerospace Control Center Department of Computer Science and Technology Tsinghua University Key Laboratory for Information System Security Ministry of Education of China Tsinghua National Laboratory for Information Science and Technology Institut National de Recherche en Informatique et en Automatique(INRIA)

Particle systems are important building block for simulating vivid and detail-rich effects in virtual *** of the most difficult aspects of particle systems has been detecting collisions between particles and mesh *** to the huge computation,a variety of proxy-based approaches have been proposed recently to perform visually correct ***,all either limit the complexity of the scene,fail to guarantee non-penetration,or are too slow for real-time use with many *** this paper,we propose a new octree-based proxy for colliding particles with meshes on the *** approach works by subdividing the scene mesh with an octree in which each leaf node associates with a representative normal corresponding to the normals of the triangles that intersect the *** present a view-visible method,which is suitable for both closed and non-closed models,to label the empty leaf nodes adjacent to nonempty ones with appropriate back/front property,allowing particles to collide with both sides of the scene *** show how collisions can be performed robustly on this proxy structure in place of the original mesh,and describe an extension that allows for fast traversal of the octree structure on the *** experiments show that the proposed method is fast enough for real-time performance with millions of particles interacting with complex scenes.

关键词： particle systems collision detection octree-based proxy GPU

Simulating Human Visual Perception in Nighttime Illumination

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Tsinghua Science and Technology 2009年第1期14卷 133-138页

作者：周宁董未名王家廞 Paul jean.claude Department of Computer Science and Technology Tsinghua University INRIA Lorraine

This paper presents an image-based algorithm for simulating the visual adaptation of the human visual system to various illuminations, especially in dark nighttime conditions. The human visual system exhibits different characteristics depending on the illumination intensity, with photopic vision in bright conditions, scotopic vision in dark conditions, and mesopic vision between these two. A computational model is designed to simulate multiple features of mesopic vision and scotopic vision, including the chromaticity change, luminance change, and visual acuity loss. The system uses a source image under bright illumination as input. Then assuming that the viewer has already adapted to the new conditions, the color spectrum of the input image is reconstructed to replace the source with modifications of the chromaticity and the luminance of the relighted scene. A bilateral filter is used to simulate the visual acuity loss. The model parameters have clear physical meanings and can be obtained from experimental data to achieve realistic *** algorithm can be used not only for visual perception simulation, but also as a day-for-night tool to produce realistic nighttime images from daytime images.

关键词： Image enhancement

Ultrafast synthesis and sintering of materials in a single running experiment approach by using electric fields

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Journal of Advanced Ceramics 2019年第2期8卷 265-277页

作者： Lílian M.JESUS Ronaldo S.SILVA jean.claude M’PEKO Sao Carlos Institute of Physics University of Sao Paulo(USP)P.O.Box:369CEP:13560-970 Sao CarlosSPBrazil Group of Advanced Ceramic Materials Department of PhysicsFederal University of Sergipe(UFS)CEP:49100-000 Sao CristovaoSEBrazil Department of Physics Federal University of Sao Carlos(UFSCar)13560-905 Sao CarlosSPBrazil

Processing of materials in the form of ceramics normally involves several steps including calcination at a relatively low temperature for synthesis of the end-product powder and sintering at a high temperature for *** work we have been developing introduces a novel approach enabling synthesis plus sintering of materials in a single running experiment by using electric fields,ending with dense ceramics that display grains noticeably finer than in conventional *** new paradigm is fully illustrated with experiments conducted on amorphous CaCu3Ti4O12 precursor powder,shown to experience,on heating,crystallization through intermediate phases,followed by chemical reaction leading to synthesis of the end-product powder,plus densification depending on field *** processing time and furnace temperature are considerably reduced,demonstrating that enhanced synthesis and sintering rates applied under field *** results found in Bi2/3Cu3Ti4O12are also *** different factors that may contribute to this unique scenario,including Joule heating,defect generation,and reduction of free energy for nuclei formation promoted by the applied field,are briefly ***,the findings we bring here are exclusive as they show an exploitable way that allows rapid processing of materials with good control over particle and grain coarsening.

关键词： field-assisted processing synthesis sintering microstructure dielectric response

The local contribution to the microwave background radiation

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Research in Astronomy and Astrophysics 2015年第4期15卷 461-474页

作者： jean.claude Pecker Jayant V.Narlikar Francois Ochsenbein Chandra Wickramasinghe College de France Inter-University Centre for Astronomy and Astrophysics Centre de Donnees astronomiques de Strasbourg (CDS) Observatoire de Strasbourg11rue de l’Universite 67000 StrasbourgFrance Buckingham Centre for Astrobiology University of Buckingham

The observed microwave background radiation （MBR） is commonly in- terpreted as the relic of an early hot universe, and its observed features （spectrum and anisotropy） are explained in terms of properties of the early universe. Here we describe a complementary, even possibly alternative, interpretation of MBR, first proposed in the early 20th century, and adapt it to modern observations. For example, the stellar Hipparcos data show that the energy density of starlight from the Milky Way, if suit- ably thermalized, yields a temperature of ~2.81 K. This and other arguments given here strongly suggest that the origin of MBR may lie, at least in a very large part, in re-radiation of thermalized galactic starlight. The strengths and weaknesses of this alternative radical explanation are discussed.

关键词： Galaxy: stellar content -- (cosmology:) cosmic microwave background-- cosmology: observations

Salicylic Acid Regulates Pollen Tip Growth ：hrough an NPR3/NPR4-1ndependent Pathway

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Molecular Plant 2016年第11期9卷 1478-1491页

作者： Duoyan Rong Nan Luo jean.claude Mollet Xuanming Liu Zhenbiao Yang State Key Laboratory of Chemo/Biosensing and Chemometrics Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation College of Biology Hunan University Changsha 410082 China Department of Botany and Plant Sciences and Center for Plant Cell Biology Institute of Integrated Genome Biology University of California Riverside CA 92521 USA Normandie Univ UniRouen Laboratoire Glycobiologie et Matrice Extracellulaire V6getale Institute for Research and Innovation in Biomedicine Vegetal Agronomie Sol et Innovation 76821 Mont-Saint-Aignan France

Tip growth is a common strategy for the rapid elongation of cells to forage the environment and/or to target to long-distance destinations. In the model tip growth system of Arabidopsis pollen tubes, several small- molecule hormones regulate their elongation, but how these rapidly diffusing molecules control extremely localized growth remains mysterious. Here we show that the interconvertible salicylic acid （SA） and meth- ylated SA （MESA）, well characterized for their roles in plant defense, oppositely regulate Arabidopsis pollen tip growth with SA being inhibitory and MeSA stimulatory. The effect of SA and MeSA was independent of known NPR3/NPR4 SA receptor-mediated signaling pathways. SA inhibited clathrin-mediated endocytosis in pollen tubes associated with an increased accumulation of less stretchable demethylated pectin in the apical wall, whereas MeSA did the opposite. Furthermore, SA and MeSA alter the apical activation of ROP1 GTPase, a key regulator of tip growth in pollen tubes, in an opposite manner. Interestingly, both MeSA methylesterase and SA methyltransferase, which catalyze the interconversion between SA and MESA, are localized at the apical region of pollen tubes, indicating of the tip-localized production of SA and MeSA and consistent with their effects on the apical cellular activities. These findings suggest that local generation of a highly diffusible signal can regulate polarized cell growth, providing a novel mechanism of cell polarity control apart from the one involving protein and mRNA polarization.

关键词： SA (salicylic acid) MeSA (methyl salicylic acid) endocytosis FM4-64 CRIB4-GFP ROP activity

Local Plants Potentially Suitable for Phytoremediation of Soils Polluted by Heavy Metals: The Case of Landfill Sites

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Journal of Geoscience and Environment Protection 2024年第7期12卷 72-88页

作者： Kpan Kpan Kouakou Gains Touré Mamadou Ouattara Nouffou Doudjo Kouassi Kouadio claude Ehouman N’guetta Moïse Ouattara Djibril Tiho Seydou UFR Sciences de la Nature Universit Nangui Abrogoua Abidjan Cte dIvoire UFR Agroforesterie Universit Jean Lorougnon Gud Daloa Cte dIvoire

Landfills are contaminated sites that need to be cleaned up to prevent human and environmental exposure to pollutants. This article aims to identify local plants capable of restoring soil polluted by heavy metals. To this end, plant species at the Bonoua landfill were inventoried. X-ray fluorescence spectrometry was used to determine the heavy metal content of soil and plants from the landfill. The bioconcentration factor (BCF) of metals in plants was evaluated. The Bonoua landfill is covered with 62 plant species, comprising 28 botanical families and 50 genera. The BCF varied from 0.08 (titanium) to 2.27 (strontium) for Phyllanthus amarus;from 0.06 (titanium) to 1.83 (copper) for Alternanthera sessilis and from 0.03 (arsenic) to 2.10 (strontium) for Amaranthus spinosus. Phyllanthus amarus, Alternanthera sessilis, and Amaranthus spinosus are strontium-accumulating species (BCF > 1). Similarly, copper BCF values were above 1 for Phyllanthus amarus, and Alternanthera sessilis. These two plant species are therefore copper accumulators. In short, Phyllanthus amarus, Alternanthera sessilis, and Amaranthus spinosus are candidate species for phytoremediation of heavy metal-polluted soils, given their BCF > 1.

关键词： Heavy Metals Phytoremediation Phyllanthus amarus Alternanthera sessilis Amaranthus spinosus

Seasonal changes in the parasite prevalence of a small Malagasy lemur species (Lepilemur edwardsi)

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Integrative Zoology 2023年第3期18卷 427-439页

作者： Janina BETHGE jean.claude RAZAFIMAMPIANDRA Arne WULFF Kathrin H.DAUSMANN Institute of Zoology Functional EcologyUniversität HamburgHamburgGermany Mention Zoologie et BiodiversitéAnimale Facultédes SciencesUniversitéd’AntananarivoAntananarivoMadagascar

Parasitic infections can impact theﬁtness of individuals and can have inﬂuence on animals’population *** individuals’parasite prevalence often changes depending on external or seasonal changes,for example,rainfall and ambient temperatures,but also on internal changes,for example,changes in body *** this study we aimed to identify the environmental factors that may inﬂuence the intestinal parasite and ectoparasite prevalence of the folivorous Malagasy primate species,Lepilemur edwardsi,living in a seasonal dry deciduous *** living in this habitat have to adapt to seasonal changes of ambient temperature,with almost no precipitation during the dry season and hence strongﬂuctuations of resource availability throughout the *** sampled the feces and ectoparasites of *** throughout the *** parasite prevalence increased from the wet to the dry season and was highest in the late dry season,which might be due to the accompanying decrease in diet ***,ectoparasite prevalence decreased in the dry season,presumably due to the prevailing unfavorable environmental conditions for the development of ectoparasites(i.e.,mites and ticks).Paired with the higher resting metabolism and stress level of *** during the late dry season,it seems that this species may struggle when dry seasons intensify in its habitat.

关键词： ectoparasites intestinal parasites Madagascar primates seasonality