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On Stochastic Error and Computational Efficiency of the Markov Chain Monte Carlo Method

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Communications in Computational Physics 2014年第7期16卷 467-490页

作者： Jun Li philippe Vignal Shuyu Sun Victor M.Calo Center for Numerical Porous Media King Abdullah University of Science and TechnologyThuwalSaudi Arabia Material Science and Engineering King Abdullah University of Science and TechnologyThuwalSaudi Arabia AppliedMathematics and Computational Science Earth Sciences and EngineeringKing Abdullah University of Science and TechnologyThuwalSaudi Arabia.

InMarkov ChainMonte Carlo(MCMC)simulations,thermal equilibria quantities are estimated by ensemble average over a sample set containing a large number of correlated *** samples are selected in accordance with the probability distribution function,known from the partition function of equilibrium *** the stochastic error of the simulation results is significant,it is desirable to understand the variance of the estimation by ensemble average,which depends on the sample size(i.e.,the total number of samples in the set)and the sampling interval(i.e.,cycle number between two consecutive samples).Although large sample sizes reduce the variance,they increase the computational cost of the *** a given CPU time,the sample size can be reduced greatly by increasing the sampling interval,while having the corresponding increase in variance be negligible if the original sampling interval is very *** this work,we report a few general rules that relate the variance with the sample size and the sampling *** results are observed and confirmed *** variance rules are derived for theMCMCmethod but are also valid for the correlated samples obtained using other Monte Carlo *** main contribution of this work includes the theoretical proof of these numerical observations and the set of assumptions that lead to them.

关键词： Phase coexistence Gibbs ensemble molecular simulation Markov Chain Monte Carlo method variance estimation blocking method

Acetic acid additive in NaNO_(3)aqueous electrolyte for long-lifespan Mg-air batteries

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Journal of Magnesium and Alloys 2024年第2期12卷 825-839页

作者： Yaqing Zhou Fan Sun Gunahua Lin Sandrine Zanna Antoine Seyeux philippe Marcus Jolanta´Swiatowska Chimie ParisTech-CNRS PSL UniversityInstitut de Recherche de Chimie Paris11 rue Pierre et Marie CurieParis 75005France

Mg-air batteries have attracted tremendous attention as a potential next-generation power source for portable electronics and e-transportation due to their remarkable high theoretical volumetric energy density,environmental sustainability,and ***,the fast hydrogen evolution reaction(HER)in NaCl-based aqueous electrolytes impairs the performance of Mg-air batteries and leads to poor specific capacity,low energy density,and low ***,the conventionally used NaCl solute was proposed to be replaced by NaNO_(3)and acetic acid additive as a corrosion inhibitor,therefore an electrolyte engineering for long-life time Mg-air batteries is *** resulting Mg-air batteries based on this optimized electrolyte demonstrate an improved discharge voltage reaching~1.8 V for initial 5 h at a current density of 0.5 mA/cm^(2) and significantly prolonged cells'operational lifetime to over 360 h,in contrast to only~17 h observed in NaCl electrolyte.X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry were employed to analyse the composition of surface film and scanning electron microscopy combined with transmission electron microscopy to clarify the morphology changes of the surface layer as a function of acetic acid *** thorough studies of chemical composition and morphology of corrosion products have allowed us to elucidate the working mechanism of Mg anode in this optimized electrolyte for Mg-air batteries.

关键词： Acetic acid additive in NaNO_(3)electrolyte Electrolyte engineering Corrosion surface film Surface characterization Hydrogen evolution

Performance optimization of grid aggregation in spatial data warehouses

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International Journal of Digital Earth 2015年第12期8卷 970-988页

作者： Myoung-Ah Kang Mehdi Zaamoune François Pinet Sandro Bimonte philippe Beaune LIMOS-CNRS UMR 6158 ISIMAUniversitéBlaise PascalAubièreFrance Irstea UR TSCFClermont-FerrandFrance Agaetis Clermont-FerrandFrance

The problem of storage and querying of large volumes of spatial grids is an issue to *** this paper,we propose a method to optimize queries to aggregate raster grids stored in *** our approach,we propose to estimate the exact result rather than calculate the exact *** approach reduces query execution *** advantage of our method is that it does not require implementing or modifying functionalities of database management *** approach is based on a new data structure and a specific model of SQL *** work is applied here to relational data warehouses.

关键词： data warehouse database modelling geographical information system

Ultrafiltration for environmental safety in shellfish production: A case of bloom emergence

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Water Science and Engineering 2021年第1期14卷 46-53页

作者： Clemence Cordier Alexandra Voulgaris Christophe Stavrakakis Patrick Sauvade Franz Coelho philippe Moulin Aix-Marseille Universite M2P2 UMR 7340Equipe Procedes MembranairesLaboratoire de Mecanique Modelisation et Procedes PropresAix en Provence 13545France Plateforme Experimentale Mollusques Marins Station Ifremer de BouinPolder des ChampsBouin 85230France Suez-Aquasource Toulouse 31029France

The process of ultrafiltration(UF)of natural seawater often encounters the problems of variation in water quality and coastal *** validate the feasibility of UF in shellfish farms,this study compared the hydraulic performance and pollutant removal efficiency of the UF process with those of the commonly used treatments that combine several filtration steps with ultraviolet(UV)*** comparison was conducted in the cases of natural seawater and a coastal *** that the UF process encountered the specific type of pollution,this study evaluated the filtration performance of the UF process and the retention of total suspended solids(TSS),bacteria,phytoplankton,and zooplankton.A real coastal bloom was considered in the case study of an experimental shellfish hatchery/nursery in *** results show that both treatments were able to eliminate approximately 50%of ***,in contrast with UV treatment combined with filtration,the UF process retained total amounts of phytoplankton,zooplankton,and bacteria in the *** the hydraulic performance of the UF process was impacted by the coastal bloom,the fouling was eliminated through chemical cleaning conducted at a frequency less than once per 12 *** the severe pollution,this study confirmed the pollution resistance and treatment performance of the UF process,indicating that UF has the potential to enhance the biosecurity level.

关键词： Ultrafiltration Environmental safety Aquaculture Shellfish culture Coastal bloom

Health care-associated hepatitis C virus infection

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World Journal of Gastroenterology 2014年第46期20卷 17265-17278页

作者： Bruno Pozzetto Meriam Memmi Olivier Garraud Xavier Roblin philippe Berthelot Groupe Immunité des Muqueuses et Agents Pathogènes (GIMAP EA3064) Faculty of Medecine of Saint-EtienneUniversity of Lyon42023 Saint-EtienneFrance Department of Infectious Agents and Hygiene University-Hospital of Saint-Etienne42055 Saint-EtienneFrance Institut National de la Transfusion Sanguine 75015 ParisFrance Department of Gastroenterology and Hepatology University-Hospital of Saint-Etienne42055 Saint-EtienneFrance Department of Infectious Diseases and Hygiene University-Hospital of Saint-Etienne42055 Saint-EtienneFrance

Hepatitis C virus(HCV)is a blood-borne pathogen that has a worldwide distribution and infects millions of ***-associated HCV infections represented a huge part of hepatitis C burden in the past via contaminated blood and unsafe injections and continue to be a serious problem of public *** present review proposes a panorama of health care-associated HCV infections via the three mode of contamination that have been identified:(1)infected patient to non-infected patient;(2)infected patient to non-infected health careworker(HCW);and(3)infected HCW to non infected *** each condition,the circumstances of contamination are described together with the means to prevent *** a whole,the more important risk is represented by unsafe practices regarding injections,notably with the improper use of multidose vials used for multiple *** questions of occupational exposures and infected HCWs are also *** terms of prevention and surveillance,the main arm for combating care-associated HCV infections is the implementation of standard precautions in all the fields of cares,with training programs and audits to verify their good *** must be sensitized to the risk of blood-borne pathogens,notably by the use of safety devices for injections and good hygiene practices in the operating theatre and in all the invasive *** providers performing exposed-prone procedures must monitor their HCV serology regularly in order to detect early any primary infection and to treat it without *** the need to stay vigilant because HCV infection is often a hidden risk,it can be hoped that the number of people infected by HCV via health care will decrease very significantly in the next years.

关键词： Hepatitis C virus Health care-associated infection Health care worker Standard precautions Hemodialysis Unsafe injections Occupational exposure Antiviral drugs

Elastic property determination of nanostructured W/Cu multilayer films on a flexible substrate

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Acta Mechanica Sinica 2019年第6期35卷 1210-1216页

作者： Wei He Meidong Han Shibin Wang philippe Goudeau Eric Le Bourhis Pierre Olivier Renault Department of Mechanics Tianjin UniversityTianjin 300350China AML School of Aerospace EngineeringTsinghua UniversityBeijing 100084China School of Aircraft Engineering Nanchang Hangkong UniversityNanchang 330063China Department of Physics and Mechanics of Materials Institute PprimeCNRSPoitiers UniversityFuturoscope 86962France

An experimental method for a single layer is extended to determine the elastic properties of nanostructured W/C u multilayers on a flexible *** strain difference between the W/Cu-polyimide-W/Cu composite and the uncoated substrate,measured by dual digital image correlation,allows us to extract the effective Young's modulus of W/Cu multilayers(20 periods)equaling 216±13 *** element method is then performed,which agrees well with the experiment and classical rule of mixture(ROM)theory demonstrating that the extension to multilayers is effective and *** numerical analysis also interestingly shows that the strain difference is linearly related to the thickness ratio(W/Cu),periods and sublayer thickness,*** contrast to ROM theory,this approach could potentially be used for the evaluation of properties and design of emerging/unknown functional multilayers,whether or not they are crystalline or amorphous.

关键词： Nanostructured multilayers Young's modulus Dual digital image correlation Finite element method

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Poetics of history

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Novel Bio-based Flame Retardant Systems Derived from Tannic Acid

作者： philippe Lacoue-Labarthe

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Journal of Renewable Materials 2018年第6期6卷 559-572页

作者： Fouad LAOUTID Valeriia KARASEVA Lucie COSTES Sylvain BROHEZ Rosica MINCHEVA philippe DUBOIS Laboratory of Polymeric&Composite Materials Materia Nova Research Center-University of Mons-UMONSPlace du Parc 23B-7000 Mons(Belgium) Service de Génie des Procédés Chimiques FacultéPolytechnique-University of Mons-UMONSPlace du Parc 23B-7000 Mons(Belgium)

In this study,tannic acid(TA)was investigated as flame retardant agent for *** strategies to modify its thermal degradation pathway have been explored in order to improve its charring *** first one consists in combining TA with organomodified montmorillonite(oMMT),and enables limiting the thermo-oxidative degradation of TA and promoting the formation of an effective char ***-retardant(FR)behavior of PLA-based composition has been found to be positively impacted by this combination since a reduction of the peak of Heat Release Rate(PHRR),more important than the value recorded when oMMT and tannic acid are used separately,has been *** second strategy,in which tannic acid was associated with a biosourced phosphorousbased compounds,*** phytate salt,evidenced another alternative allowing enhancing TA flame retardant effect at 30 wt%loading *** third and last strategy explored aims to chemically modify TA via a chemical grafting of phosphoric acid *** phosphorylated TA was shown to present the most effective flame-retardant(FR)***,an important reduction of PLA molecular weight was observed.

关键词： Tannic acid biobased flame retardants char formation polylactide biopolymers

Relationship between Carbon Isotope Discrimination and Grain Yield in Spring Wheat Cultivated under Different Water Regimes

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Journal of Integrative Plant Biology 2007年第10期49卷 1497-1507页

作者： Xing Xu Hanming Yuan Shuhua Li Richard Trethowan philippe Monneveux Ningxia University Yinchuan China750021 Ningxia Key Laboratory of Agro-Biotechnology Academy of Agriculture and Forestery Sciences Yinchuan China750021 International Center for Maize and Wheat Improvement A.P. 6-641 Mexico D.F. 06600 Mexico SupAgro Montpellier Montpellier Cedex France34060

In C3 plants, carbon isotope discrimination （A） has been proposed as an indirect selection criterion for grain yield. Reported correlations between A and grain yield however, differ highly according to the analyzed organ or tissue, the stage of sampling, and the environment and water regime. In a first experiment carried out in spring wheat during two consecutive seasons in the dry conditions of northwest Mexico （Ciudad Obregon, Sonora）, different water treatments were applied, corresponding to the main water regimes available to spring wheat worldwide, and the relationships between A values of different organs and grain yield were examined. Under terminal （post-anthesis） water stress, grain yield was positively associated with A in grain at maturity and in leaf at anthesis, confirming results previously obtained under Mediterranean environments. Under early （pre-anthesis） water stress and residual moisture stress, the association between grain A and yield was weaker and highly depended on the quantity of water stored in the soil at sowing. No correlation was found between A and grain yield under optimal irrigation. The relationship between A and grain yield was also studied during two consecutive seasons in 20 bread wheat cultivars in the Ningxia region （Northern China）, characterized by winter drought （pre-anthesis water stress）. Wheat was grown under rainfed conditions in two locations （Guyuan and Pengyang） and under irrigated conditions in another two （Yinchuan and Huinong）. In Huinong, the crop was also exposed to salt stress. Highly significant positive associations were found between leaf and grain A and grain yields across the environments. The relationship between A and yield within environments highly depended on the quantity of water stored in the soil at sowing, the quantity and distribution of rainfall during the growth cycle, the presence of salt in the soil, and the occurrence of irrigation before anthesis. These two experiments confirmed the value of

关键词： carbon isotope discrimination drought salinity spring wheat yield.