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Effect of an adverse pressure gradient on the streamwise Reynolds stress profile maxima in a turbulent boundary layer

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Acta Mechanica Sinica 2013年第3期29卷 395-398页

作者： Wei Ma xavier Ottavy Li-Peng Lu Francis Leboeuf Laboratoire de Mécanique des Fluides et d'Acoustique Ecole Centrale de Lyon School of Jet Propulsion Beihang University

It is widely accepted that in a turbulent boundary layer （TBL） with adverse pressure gradient （APG） an outer peak usually appears in the profile of streamwise Reynolds stress. However, the effect of APG on this outer peak is not clearly understood. In this paper, the effect of APG is analysed using the numerical and experimental results in the literature. Because the effect of upstream flow is inherent in the TBL, we first analyse this effect in TBLs with zero pressure gradient on flat plates. Under the individual effect of upstream flow, an outer peak already appears in the profile of streamwise Reynolds stress when the TBL continues developing in the streamwise direction. The APG accelerates the appearance of the outer peak, instead of being a trigger.

关键词： Turbulent boundary layer · Pressure gradient · Reynolds stress

Verapamil and vasospastic angina： underuse in the elderly population

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Journal of Geriatric Cardiology 2017年第7期14卷 430-435页

作者： xavier Humbert Vincent Roule Paul Milliez Joachim Alexandre Department of General Medicine Medical School Caen France Department of Pharmacology CHU de Caen Caen France Normandie University UNICAEN CHU Caen Signalisation eleetrophysiologie et imagerie des lesions d'ischOmie-reperfusion myocardique Caen France Department of Cardiology CHU de Caen Caen France

The first case of Prinzmetal angina was described in 1959 by Prinzmetal, et al. Since this description, several triggering factors have been associated with vasospastic angina （VA） and included： illicit drugs such as cocaine, amphetamine or marijuana, but also bitter-orange, alcohol, butane, chemotherapy drugs, over-the-counter medication and different antibiotics. Smoking is also a major risk factor for developing VA.t21 Thus, except for smoking, many of conventional atherosclerosis risk factors do not appear to be applicable to VA.t21 However, vasospastic angina can also occur without any triggering factor.

关键词： Calcium antagonists Elderly population Prinzmetal angina Variant angina Verapamil

The potential leaching and mobilization of trace elements from FGD-gypsum of a coal-fired power plant under water re-circulation conditions

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Journal of Environmental Sciences 2015年第6期27卷 72-80页

作者： Patricia Córdoba Iria Castro Mercedes Maroto-Valer xavier Querol Centre for Innovation on Carbon Capture and Storage Institute of Mechanical Process and Energy Engineering Heriot-Watt University Institute of Environmental Assessment and Water Research

Experimental and geochemical modelling studies were carried out to identify mineral and solid phases containing major, minor, and trace elements and the mechanism of the retention of these elements in Flue Gas Desulphurisation（FGD）-gypsum samples from a coal-fired power plant under filtered water recirculation to the scrubber and forced oxidation conditions. The role of the p H and related environmental factors on the mobility of Li, Ni, Zn, As, Se, Mo, and U from FGD-gypsums for a comprehensive assessment of element leaching behaviour were also carried out. Results show that the extraction rate of the studied elements generally increases with decreasing the p H value of the FGD-gypsum leachates. The increase of the mobility of elements such as U, Se, and As in the FGD-gypsum entails the modification of their aqueous speciation in the leachates; UO2SO4, H2 Se, and HAs O2 are the aqueous complexes with the highest activities under acidic *** speciation of Zn, Li, and Ni is not affected in spite of p H changes; these elements occur as free cations and associated to SO4 ^2 in the FGD-gypsum leachates. The mobility of Cu and Mo decreases by decreasing the p H of the FGD-gypsum leachates, which might be associated to the precipitation of Cu Se2 and Mo Se2, respectively. Time-of-Flight mass spectrometry of the solid phase combined with geochemical modelling of the aqueous phase has proved useful in understanding the mobility and geochemical behaviour of elements and their partitioning into FGD-gypsum samples.

关键词： Geochemical modelling studies Trace elements Leaching Landfills FGD-gypsum ToF mass spectrometry

Analysis of a Prototypical Multiscale Method Coupling Atomistic and Continuum Mechanics:the Convex Case

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Acta Mathematicae Applicatae Sinica 2007年第2期23卷 209-216页

作者： xavier Blanc Claude Le Bris FrédéricLegoll Laboratoire J.L.-Lions Université Pierre et Marie CurieBoite courrier 187F-75252 ParisFrance CERMICS Ecole Nationale des Ponts et Chaussées 6 et 8 avenue Blaise PascalCité DescartesF-77455 Marne-la-Vallée and MICMACInria RocquencourtF-78153 Le ChesnayFrance CERMICS Ecole Nationale des Ponts et Chaussées 6 et 8 avenue Blaise PascalCité DescartesF-77455 Marne-la-Vallée and MICMACInria RocquencourtF-78153 Le ChesnayFrance EDF R & D1 avenue du Général de GaulleF-92140 ClamartFrance

In order to describe a solid which deforms smoothly in some region, but non smoothly in some other region, many multiscale methods have been recently proposed that aim at coupling an atomistic model （discrete mechanics） with a macroscopic model （continuum mechanics）. We provide here a theoretical basis for such a coupling in a one-dimensional setting, in the case of convex energy.

关键词： Multiscale methods variational problems continuum mechanics discrete mechanics

Hepatocyte cryopreservation:Is it time to change the strategy?

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World Journal of Gastroenterology 2010年第1期16卷 1-14页

作者： xavier Stéphenne Mustapha Najimi Etienne M Sokal Catholic University of Louvain and St Luc Clinics Paediatric Department(HPED)PEDI unitLaboratory of Paediatric Hepatology and Cell Therapy

Liver cell transplantation presents clinical benefit in patients with inborn errors of metabolism as an alternative,or at least as a bridge,to orthotopic liver *** success of such a therapeutic approach remains limited by the quality of the transplanted *** remains the best option for long-term storage of hepatocytes,providing a permanent and sufficient cell ***, isolated adult hepatocytes are poorly resistant to such a process,with a significant alteration both at the morphological and functional ***,the aim of the current review is to discuss the state of the art regarding widely-used hepatocyte cryopreservation protocols,as well as the assays performed to analyse the post-thawing cell quality both in vitro and in vivo. The majority of studies agree upon the poor quality and efficiency of cryopreserved/thawed hepatocytes as compared to freshly isolated *** ice formation or exposure to hyperosmotic solutionsremains the main phenomenon of cryopreservation process,and its effects on cell quality and cell death induction will be *** increased knowledge and understanding of the cryopreservation process will lead to research strategies to improve the viability and the quality of the cell suspensions after *** strategies,such as vitrification,will be discussed with respect to their potential to significantly improve the quality of cell suspensions dedicated to liver cell-based therapies.

关键词： Hepatocyte Cryopreservation Quality Mitochondria Intracellular ice formation

Raised into Ruins： Transforming Debris in Contemporary Photography from China

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Frontiers of Literary Studies in China-Selected Publications from Chinese Universities 2017年第2期11卷 263-297页

作者： xavier Ortells-Nicolau Department of Modern Languages and Literatures and English Studies Universitat deBarcelona Facultat de Filologia Gran Via de les Corts Catalanes 585 Barcelona 08007Spain

At the turn of the twenty-first century, contemporary art from China has displayed a recurrent engagement with urban ruins. Painting, performance, film, and photography have turned the rubble of demolition and construction works, an outcome of the vast urban development programs of the past few decades, into a powerful symbol of China＇s contemporary milieu. Critical and academic approaches to contemporary Chinese art have rightly inquired about the meaning of these ruins, in a process that has also reevaluated the place of these images in the representational traditions of China. Starting with these academic perspectives, this paper situates images of ruination in contemporary Chinese art in dialogue with transnational debates on the meaning and epistemology of the ruin, to argue for an essential element of constructedness in the representations of ruins. Photographic series by Wang Qingsong, Jiang Pengyi, and Yang Yongliang are analyzed as examples of an active appropriation of the process of ruin creation from a critical stance. Recycling urban wasteful rubble into an aesthetic object, these photo artists generate alternative visions of urban development and its consequent demolition and contribute to the negotiation of the meaning of the ruin.

关键词： contemporary photography constructedness ruins JiangPengyi Wang Qingsong Yang Yongliang

A hierarchical optimisation framework for pigmented lesion diagnosis

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CAAI Transactions on Intelligence Technology 2022年第1期7卷 34-45页

作者： Audrey Huong KimGaik Tay KokBeng Gan xavier Ngu Department of Electronic Engineering Universiti Tun Hussein Onn MalaysiaParit RajaMalaysia Department of Electrical Electronic&Systems EngineeringUniversiti Kebangsaan MalaysiaBangiMalaysia Institute of Integrated Engineering Universiti Tun Hussein Onn MalaysiaParit RajaMalaysia

The study of training hyperparameters optimisation problems remains underexplored in skin lesion *** is the first report of using hierarchical optimisation to improve computational effort in a four-dimensional search space for the *** authors explore training parameters selection in optimising the learning process of a model to differentiate pigmented lesions *** the authors'demonstration,pretrained GoogleNet is fine-tuned with a full training set by varying hyperparameters,namely epoch,mini-batch value,initial learning rate,and gradient *** iterative search of the optimal global-local solution is by using the derivative-based *** authors used non-parametric one-way ANOVA to test whether the classification accuracies differed for the variation in the training *** authors identified the mini-batch size and initial learning rate as parameters that significantly influence the model's learning *** authors'results showed that a small fraction of combinations(5%)from constrained global search space,in contrarily to 82%at the local level,can converge with early stopping *** mean(standard deviation,SD)validation accuracies increased from 78.4(4.44)%to 82.9(1.8)%using the authors'*** fine-tuned model's performance measures evaluated on a testing dataset showed classification accuracy,precision,sensitivity,and specificity of 85.3%,75.6%,64.4%,and 97.2%,*** authors'system achieves an overall better diagnosis performance than four state-of-the-art approaches via an improved search of parameters for a good adaptation of the model to the authors'*** extended experiments also showed its superior performance consistency across different deep networks,where the overall classification accuracy increased by 5%with this *** approach reduces the risk of search being trapped in a suboptimal solution,and its use may be expanded to network architecture optimisation for

关键词： hierarchical hyperparameter optimisation pigmented lesion search

Phosphine functionalised multiwalled carbon nanotubes:A new adsorbent for the removal of nickel from aqueous solution

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Journal of Environmental Sciences 2012年第6期24卷 1133-1141页

作者： Muleja Anga Adolph Yangkou Mbianda xavier Pillay Kriveshini Krause Rui Department of Chemical Technology University of JohannesburgDoornfontein Campus P.O Box 17011JohannesburgSouth Africa

Synthesised triphenylphosphine-linked multiwalled carbon nanotubes （Tpp-MWCNTs） were used to study the adsorption of nickel in aqueous solutions and their adsorption capabilities were compared with purified *** adsorption capacity increased with an increase in pH for all *** adsorption equilibrium was reached in 40 and 30 min for purified MWCNTs and Tpp-MWCNTs,*** Freundlich and Langmuir isotherms used to investigate the adsorption process fitted the experimental data well with the correlation coefficient R 2 close to 1 for all *** the other hand,the experimental data fitted well with a pseudo secondorder *** speciation of nickel also influenced the adsorption on the purified and *** adsorbents used in this study showed superior adsorption capacity when compared to other adsorbents reported in the literature.

关键词： phosphine functionalised multiwalled carbon nanotubes adsorbent XPS remediation nickel

A European digital accelerometric database:statistical analysis of engineering parameters of small to moderate magnitude events

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Earthquake Engineering and Engineering Vibration 2014年第4期13卷 583-597页

作者： Carlos S.Oliveira Gerard Gassol xavier Goula Teresa Susagna Instituto Superior Técnico Universidade de Lisboa Institut Cartogràfic i Geològic de Catalunya

During the NERIES Project, an accelerometric database containing European digital information was developed. Besides event and station metadata, ground motion parameters, computed in a homogeneous manner, were assembled： PGA, PGV, AI, TD, CAV, H1 and PSV（f,5%）（19,961 components, 2629 events, 547 stations）. Merging small and moderate magnitude events produced a unique database capable of providing important information such as：（i） Correlations between several ground motion parameters follow analogous trends as in previous worldwide datasets, with slight corrections. （ii） Although PGA attenuations with distance show great uncertainties, four recent GMPEs recommended for Europe fit quite well the central 50% data interval for the distance range 10 〈 R 〈 200 kin; outside these distances, they do not fit. （iii） Soil amplification ratios indicate that weak motion （low magnitudes and larger distances） shows larger amplification than strong motion （short distances and large magnitudes） as represented in UBC97 for the USA, but not in EC8 for Europe. （iv） Average spectral shapes are smaller than in the EC8. （v） Differences in amplification factors for PGA, PGV and HI for EC8 soil classes B and C, and differences in spectral shapes for these soil classes, indicate that EC8, Type 2 S-coefficient should be frequency dependent, as in UBC97.

关键词： NERIES project parametric accelerometric database European region PGA EC8 soil amplification