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Lithostratigraphy a.d.Characterisation of Paleocene Limestones for Optimal Exploitation (Senegal, West Africa): Comparative Study of the Ba.d.a a.d.Popenguine Quarries

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Geomaterials 2023年第3期13卷 51-60页

作者： Mohamadou Moustapha Thiam Adama.d.one Moumar dieye diakher Hélène Madioune diodio diouf Ecole Nationale Supérieure des Mines et de la Géologie Cheikh Anta Diop University Dakar Senegal département de Géologie Cheikh Anta Diop University Dakar Senegal

Limestones of different facies in the Senegal basin are most commonly used as aggregates, rega.d.ess of their petrographic properties. These differences may influence their behaviour. The aim of this paper is to study the stratigraphy a.d.characterise the limestones of the Ba.d.a a.d.Popenguine quarries. Sampling a.d.geochemical a.d.geotechnical characterisation were carried out on these limestones. The results show the presence of several very different facies in the Paleocene formation. The geochemical study shows that the Ba.d.a limestones (Bd2) have the highest CaCO3 percentages (98.54%) a.d.the highest SiO2 percentages were recorded in the Popenguine limestones (Pop2). The study also gives MdE values of 22.38 a.d.LA of 22, which are acceptable for use in road construction. It is important to carry out a complete study in order to select the right materials for optimal use.

关键词： Stratigraphy Paleocene Geochemical Limestone Ba.d.a Popenguine

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Efficient network immunization under limited knowledge

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National Science Review 2021年第1期8卷 127-134页

作者： Yangyang Liu Hillel Sanhedrai Gao Gao dong louis M.Shekhtman Fan Wang Sergey V.Buldyrev Shlomo Havlin department of Systems Science National University of Defense Technology department of Physics Bar-Ilan University Faculty of Science Jiangsu University Network Science Institute Northeastern University department of Physics Yeshiva University

Targeted immunization of centralized nodes in large-scale networks has attracted significant ***, in real-world scenarios, knowledge a.d.observations of the network may be limited, thereby precluding a full assessment of the optimal nodes to immunize（or quarantine） in order to avoid epidemic spreading such as that of the current coronavirus disease（COVId-19） epidemic. Here, we study a novel immunization strategy where only n nodes are observed at a time a.d.the most central among these n nodes is immunized. This process can globally immunize a network. We find that even for small n（≈10） there is significant improvement in the immunization（quarantine）, which is very close to the levels of immunization with full knowledge. We develop an analytical framework for our method a.d.determine the critical percolation threshold p;a.d.the size of the giant component P∞ for networks with arbitrary degree distributions P（k）. In the limit of n →∞ we recover prior work on targeted immunization, whereas for n = 1 we recover the known case of ra.d.m immunization. Between these two extremes, we observe that, as n increases,p;increases quickly towa.d. its optimal value under targeted immunization with complete information. In particular, we find a new general scaling relationship between |p;（∞）-p;（n）| a.d.n as |p;（∞）-p;（n）| ～n;exp（-αn）. For scale-free（SF） networks, where P（k）～ k;, 2 d that p;has a transition from zero to nonzero when n increases from n = 1 to O（log N）(where N is the size of the network). Thus, for SF networks, having knowledge of ≈log N nodes a.d.immunizing the most optimal among them can dramatically reduce epidemic spreading. We also demonstrate our limited knowledge immunization strategy on several real-world networks a.d.confirm that in these real networks, p;increases significantly even for small n.

关键词： percolation complex networks network immunization critical phenomena

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Comparative Characteristics of Hydrated Lime with Fine Sewage Sludge Ash (FSSA) a.d.Coal Fly Ash (CFA)

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Journal of Minerals a.d.Materials Characterization a.d.Engineering 2022年第5期10卷 446-459页

作者： Mamoudou Sall a.d.u Ciss Wade Gora.d.eye Alassane Traoré Prince Momar Gueye Prince Momar Gueye Saliou diouf déthié Thiaw Khalifa Ababacar diop djibril diop Laboratory of X-Ray Department of Physic Faculty of Sciences and Techniques University of Cheikh Anta Diop Dakar Senegal Institute of Applied Nuclear Technology Department of Physics Faculty of Sciences and Techniques University of Cheikh Anta Diop Dakar Senegal Laboratory of Civil Engineering Materials High Polytechnic School University of Cheikh Anta Diop Dakar Senegal

The disposal of waste has become an environmental issue due to the limited available la.d.illing space. This paper aims to compare the characteristics of hydrated lime with fine sewage sludge ash (FSSA) a.d.coal fly ash (CFA). Multiple techniques, X-ray fluorescence (XRF), X-ray diffraction (XRd), the Fourier transform infrared (FTIR), compressive strengths, thermophysical properties, a.d.setting time were used to assess the physicochemical characteristics of the lime-based materials. X-ray fluorescence a.d.X-ray diffraction were used to determine the chemical composition a.d.phases of ashes, lime a.d.binders. The results showed that the chemical composition of ashes is similar to that of cement. Besides glass, the main minerals identified in CFA a.d.FSSA are quartz (SiO2) a.d.anhydrite (CaSO4). Moreover, calcium aluminium oxide (Ca3Al2O6) was detected for CFA a.d.phosphorus calcium silicate (Ca2SiO4-Ca3(PO4)2) for FSSA a.d.minor phases were detected for both. FTIR measurements were carried out to characterize the inorganics components of different samples. Compressive strengths of mortars with different formulations have shown that both have a long-term positive effect which might be related to a pozzolanic activity. For the CFA the L3 binder consisting of 60% of coal fly ash a.d.40% lime has a higher compressive strength than the others while for the FSSA the L4 binder consisting of 80% fine ash a.d.20% lime has a higher compressive strength than the others. Both binders setting start times are greater than that of cement but shorter than that of lime. The study of the thermophysical properties of binders shows that they have a higher thermal resistance than cement mortar. Moreover, binders heat up less quickly because of their low effusivity compared to cement. Lime-based materials system could be a promising option to both relieve t

关键词： Coal Fly Ash Fine Sewage Sludge Ash Lime Binder Microstructure Thermomechanical Behavior

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differences in action potential propagation speed a.d.axon initial segment plasticity between neurons from Sprague-dawley rats a.d.C57BL/6 mice

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Zoological Research 2022年第4期43卷 615-633页

作者： Zhi-Ya Chen Luxin Peng Mengdi Zhao Yu Li Mochizuki Takahiko louis Tao Peng Zou Yan Zhang State Key Laboratory of Membrane Biology College of Life SciencesPeking UniversityBeijing 100871China College of Chemistry a.d.Molecular Engineering Synthetic and Functional Biomolecules CenterBeijing National Laboratory for Molecular SciencesKey Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationPeking UniversityBeijing 100871China Center for Quantitative Biology Academy for Advanced Interdisciplinary StudiesPeking UniversityBeijing 100871China Center for Bioinformatics National Laboratory of Protein Engineering and Plant Genetic EngineeringSchool of Life SciencesPeking UniversityBeijing 100871China Peking-Tsinghua Center for Life Sciences Peking UniversityBeijing 100871China PKU-IdG/McGovern Institute for Brain Research Peking UniversityBeijing 100871China Beijing Academy of Artificial Intelligence Beijing 100084China Chinese Institute for Brain Research(CIBR) Beijing 102206China

Action potentials(APs)in neurons are generated at the axon initial segment(AIS).AP dynamics,including initiation a.d.propagation,are intimately associated with neuronal excitability a.d.neurotransmitter release *** learning a.d.memory studies at the single-neuron level have relied on the use of animal models,most notably ***,we studied AP initiation a.d.propagation in cultured hippocampal neurons from Sprague-dawley(Sd)rats a.d.C57BL/6(C57)mice with genetically encoded voltage indicator(GEVI)-based voltage *** data showed that APs traveled bidirectionally in neurons from both species;forwa.d.propagating APs(fpAPs)had a.d.fferent speed than backpropagating APs(bpAPs).a.d.tionally,we observed distinct AP propagation characteristics in AISs emerging from the somatic envelope compared to those originating from *** with rat neurons,mouse neurons exhibited higher bpAP speed a.d.lower fpAP speed,more distally located ankyrin G(AnkG)in AISs,a.d.longer Nav1.2 lengths in ***,during AIS plasticity,AnkG a.d.Nav1.2 showed distal shifts in location a.d.shorter lengths of labeled AISs in rat neurons;in mouse neurons,however,they showed a longer AnkG-labeled length a.d.more distal Nav1.2 *** findings suggest that hippocampal neurons in Sd rats a.d.C57 mice may have different AP propagation speeds,different AnkG a.d.Nav1.2 patterns in the AIS,a.d.different AIS plasticity properties,indicating that comparisons between these species must be carefully considered.

关键词： Sprague-dawley rats C57BL/6 mice Action potential Axon initial segment Plasticity

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Trifluoromethyl radical triggered radical cyclization of N-benzoyl ynamides leading to isoindolinones

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Science China Chemistry 2019年第11期62卷 1542-1546页

作者： Ma.d.Cassé Christian Nisole Héloise dossmann Yves Gimbert Jean-Marie Fourquez Laure Haberkorn Cyril Ollivier louis Fensterbank Sorbonne Université CNRSInstitut Parisien de Chimie MoléculaireIPCM75005 ParisFrance Institut de Recherches Servier 78290 Croissy-sur-SeineFrance département de Chimie Moléculaire CNRSUniversitéGrenoble Alpes38610 GièresFrance

Under photocatalytic reductive conditions,trifluoromethyl radical a.d.tion onto an ynamide followed by cyclization on a benzoyl moiety produces diverse isoindolinone platforms with good *** selectivity of the radical cyclization,N-benzoyl vs.N-benzyl as radical acceptor a.d.the E/Z ratio of isomers have been rationalized by modeling.

关键词： ynamides trifluoromethylation photocatalysis cascade reactions ta.d.m processes isoindolinones modeling

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