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cO oxidation under lean and stoichiometric conditions over ceriazirconia with very low metal contents(cu,co,Ag and pt)

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Journal of Rare Earths 2024年第9期42卷 1669-1681,I0002页

作者： J.c.martínez-munuera m.p.Yeste A.García-García mcmA Group Department of Inorganic Chemistry and Institute of MaterialsUniversity of AlicanteCarretera de San Vicente del Raspeig s/n03690San Vicente del RaspeigAlicanteSpain Solid chemistry and catalysis Group Department of Materials ScienceMetallurgic Engineering and Inorganic ChemistryInstitute of Electronic Microscopy and Materials ResearchUniversity of CádizAp.40E-11510Puerto RealCádizSpain

In this work,several ceria-zirconia based catalysts with very lo w(and equimolar) metal contents were prepared,characterised and tested for the cO oxidatio n reaction(under lean and stoichiometric conditions),trying to emulate those conditions found in a diesel oxidation catalyst(DOc) system from a diesel engine and those encountered under gasoline exhaust(λ=1).The metals chosen are cu,co,Ag and pt(as a reliable benchmark).The results reveal enormous differences among reducibility and catalytic activity despite quite similar structural and textural properties of the catalysts,showing differences among dispersion(Ag-catalyst seems to present a low level of dispersion).This catalyst seems to be characterised,as well,by a strong electronic interaction between ce and Ag centres which is suggested to yield an improved reducibility under H_(2)-TpR ***,the order in catalytic activity(cu>Ag>co≈pt>>support) seems not to follow the order found in reducibility and the cu-catalyst seems to be the most active independently on the reaction conditions,yielding nearly overlapped cO oxidation catalytic *** restingly,a stro ng correlation between the catalytic activity under the two conditions tested and the OSc values of the ce_(0.8)Zr_(0.2)O_(2)-supported metal catalysts is ***,OSc parameter measured at 150℃ can be used as a relevant descriptor to evaluate the cO oxidation activity at low and medium conversions for the investigated catalysts,much better than the H_(2)-TpR measurements.

关键词： cO oxidation Low metal content ceria-zirconia copper species OSc parameter Rare earths

Drought events influence nutrient canopy exchanges and green leaf partitioning during senescence in a deciduous forest

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Forest Ecosystems 2024年第1期11卷 110-119页

作者： J.Touche c.calvaruso p.De Donato m.-p.Turpault INRAE BEFF-54000NancyFrance UmR 7359 GeoRessourcesFaculte des Sciences-Campus des Aiguillettes54506Vandoeuvre Les NancyFrance EcoSustain Environmental Engineering OfficeResearch and DevelopmentKanfen57330France

The increase in the frequency and intensity of drought events expected in the coming decades in Western Europe may disturb forest biogeochemical cycles and create nutrient deficiencies in *** possible origin of nutrient deficiency is the disturbance of the partitioning of the green leaf pool during the leaf senescence period between resorption,foliar leaching and senesced ***,the effects of drought events on this partitioning and the consequences for the maintenance of tree nutrition are poorly *** experiment in a beech forest in meuse(France)was conducted to assess the effect of drought events on nutrient canopy exchanges and on the partitioning of the green leaf pool during the leaf senescence *** aim was to identify potential nutritional consequences of droughts for *** nutrient dynamics,including resorption,chemistry of green and senesced leaves,foliar absorption and leaching in mature beech stands from 2012 to 2019 allowed us to compare the nutrient exchanges for three nondry and three dry years(i.e.,with an intense drought event during the growing season).During dry years,we observed a decrease by almost a third of the potassium(K)partitioning to resorption(*** efficiency),thus reducing the K reserve in trees for the next growing *** result suggests that with the increased drought frequency and intensity expected for the coming decades,there will be a risk of potassium deficiency in trees,as already observed in a rainfall exclusion experiment on the same study *** foliar leaching and higher parititioning to the senesced leaves for K and phosphorus(p)were also *** addition,a slight increase in nitrogen(N)resorption efficiency occurred during dry years which is more likely to improve tree *** calcium(ca)negative resorption decreased,with no apparent consequence in our study *** results show that nutrient exchanges in the canopy and the partitioning of the green leaf

关键词： Natural drought Beech forest canopy resorption Foliar leaching Senesced leaves Nutrition

Laser-induced graphene-coated wearable smart textile electrodes for biopotentials signal monitoring

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Frontiers of materials Science 2024年第1期18卷 95-111页

作者： c.m.Vidhya Yogita maithani Sakshi Kapoor J.p.Singh Department of physics Indian Institute of Technology DelhiHauz KhasNew Delhi 110016India

This paper describes how to produce a wearable dry electrode at a reasonable cost and how to use it for the monitoring of biopotentials in *** textiles in wearable technologies have made a great advancement in the health care management and living standards of *** was manufactured using the low-cost single-step process,laser ablation of polyimide,a commercial *** dispersions were made using solvent isopropyl alcohol which has low boiling point,nontoxicity,and environmental *** successive coating of the graphene dispersion on the cotton fabric to make it conductive,the sheet resistance of the resulting fabric dropped to 3% of its initial *** laser-induced graphene(LIG)cotton dry electrodes thus manufactured are comparable to Ag/Agcl wet electrodes in terms of the skin-to-electrode impedance,measuring between 78.0 and 7.2 kΩ for the frequency between 40 Hz and 1 *** LIG cotton electrode displayed a signal-to-noise ratio of 20.17 *** to its comfort,simplicity,and good performance over a longer period of time,the textile electrode appears suited for medical applications.

关键词： biopotential electrocardiogram electromyogram flexible electrode textile porous graphene

Effect of radiative loss mechanisms on FIR thermometric parameters of Nd^(3+)-doped lithium tellurite glasses

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Journal of Rare Earths 2024年第7期42卷 1250-1257,I0002页

作者： c.Y.morassuti A.p.L Silva L.A.O.Nunes S.m.Lima L.H.c.Andrade Optical and photothermal Spectroscopy Group(GEOF) Center for Studies in Natural Resources(CERNA)State University of Mato Grosso do Sul(UEMS)C.P.351DouradosMSBrazil renato Archer Information Technology center Dom Pedro I Highway(SP-65)Km 1436-Chácaras Campos dos AmaraisCampinasSPBrazil Institute of physics of São carlos University of São PauloSão CarlosSPBrazil

Nd^(3+)-doped tellurite glasses are promising materials for thermometers based on the fluorescence intensity ratio(FIR)***,at high Nd^(3+)concentrations,energy transfer(ET)processes such as optical reabsorption and cross-relaxation can affect the Nd^(3+)emission,which has been little explored in the ***,the present work investigated the use of Nd^(3+)-doped tellurite glass(samples doped with Nd^(3+)at 0.2 mol%,0.5 mol%,2.0 mol%,and 4.0 mol%)in fluorescence thermometers,in the temperature range from 299 to 371 *** results indicate a strong dependence of the FIR parameters on the Nd^(3+)concentration,due to changes in the emission band profiles caused by optical reabsorption of the Nd^(3+)emissions and cross-relaxation processes.A decrease of the relative sensitivity of the ratio^(4)F_(5/2)→^(4)I_(9/2)/^(4)F_(3/2)→^(4)I_(9/2)is observed for samples doped with higher amounts of Nd^(3+).The maximum relative sensitivity at 299 K is 3.00%/K,which is the highest value among the reported Nd^(3+)ions.

关键词： Nd^(3+)-doped tellurite glass Fluorescence intensity ratio Optical thermometry Judd-Ofelt Rare earths

Radiative decays D*(s)→ D(s)γ in covariant confined quark model

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chinese physics c 2024年第2期48卷 45-56页

作者： c.T.Tran m.A.Ivanov p.Santorelli Q.c.Vo Department of physics HCMC University of Technology and EducationVo Van Ngan 1700000 Ho Chi Minh CityVietnam Bogoliubov Laboratory of Theoretical physics Joint Institute for Nuclear Research141980 DubnaRussia Dipartimento di Fisica"E.pancini" Universitàdi Napoli Federico ⅡComplesso Universitario di Monte S.AngeloVia CintiaEdificio 680126 NapoliItaly Istituto Nazionale di Fisica Nucleare Sezione di Napoli80126 NapoliItaly University of Science 700000 Ho Chi Minh CityVietnam

Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢ*** radiative couplings gD*Dγencoding nonperturbative QcD effects are calculated in the framework of the covariant confined quark model developed by *** compare our results with other theoretical studies and experimental *** couplings(in GeV-1)|g(D*+D+γ)|=0.45(9)and|g(D*0D0γ)|=1.72(34)calculated in our model agree with the corresponding experimental data|g(D*+D+γ)|=0.47(7)and|g(D*0D0γ)|=1.77(16).The most interesting case is the decay Ds*→Dsγ,for which a recent prediction based on light-cone sum rules at next-to-leading order|gDs*Dsγ|=0.60(19)deviates from the first(and only to date)lattice QcD result|gDs*Dsγ|=0.11(2)at nearly3σ.Our calculation yields|gDs*Dsγ|=0.29(6),which falls somehow between the two mentioned results,although it is larger than those predicted in other studies using quark models or QcD sum rules.

关键词： covariant quark model radiative decay charmed meson

magnesium oxide(mgO)nanoadsorbents in wastewater treatment:A comprehensive review

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Journal of magnesium and Alloys 2024年第5期12卷 1709-1773页

作者： H.c.S.perera V.Gurunanthanan Anoop Singh m.m.m.G.p.G.mantilaka G.Das Sandeep Arya Department of physics Khalifa UniversityAbu Dhabi12788United Arab Emirates postgraduate Institute of Science University of PeradeniyaPeradeniyaSri Lanka Department of Humanities and Sciences Guru Nanak Institutions Technical CampusIbrahimpatnamHyderabad501506India centre for Global Health research Saveetha Medical College and HospitalsSaveetha Institute of Medical and Technical SciencesChennai602105Tamil NaduIndia Department of physics University of JammuJammu and Kashmir180006India

Wastewater contamination by heavy metals and synthetic dyes presents a significant environmental challenge,necessitating effective and sustainable separation *** review article provides a detailed examination of magnesium oxide(mgO)nanoparticles as an innovative nanoadsorbent for wastewater treatment,with a specific focus on heavy metal and dye *** review comprehensively explores various aspects of mgO nanoparticles,including their structural characteristics and synthesis *** article delves into the morphology and crystallographic arrangement of mgO nanoparticles,offering insights into their structural *** the complexity of adsorption processes,the review identifies and analyzes parameters influencing the adsorption efficiency of mgO nanoparticles,such as temperature,pH,contact time,initial concentration,and co-existing *** interplay between these parameters and the adsorption capability of mgO nanoparticles emphasizes the importance of optimizing operational ***,the review assesses various synthesis methods for mgO nanoparticles,including sol-gel,hydrothermal,precipitation,green synthesis,solvothermal,and template-assisted *** discusses the advantages,limitations,and resulting nanoparticle characteristics of each method,enabling readers to grasp the implications of synthesis processes on adsorption *** comprehensive review consolidates current insights into the effectiveness of mgO nanoparticles as a potent nanoadsorbent for removing heavy metals and dyes from wastewater covering a wide spectrum of aspects related to mgO ***,there is a need to investigate the use of mgO in the treatment of actual wastewater or river water,in order to leverage its cost-effectiveness and high efficiency for practical water treatment applications in real-time.

关键词： mgO nanoparticles Nanoadsorbent Wastewater treatment Heavy metals Dye separation Adsorption Synthesis methods

post-fire recovery of puya raimondii, vegetation and birds in the puna of Huascarán National park, perú

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Journal of mountain Science 2024年第1期21卷 20-32页

作者： mery L.SUNI Giovana p.VADILLO césar ARANA Enoc JARA-pENA Letty SALINAS m.Estela pONcE paul m.RAmSAY plant physiology Laboratory Faculty of Biological SciencesUniversidad Nacional Mayor de San MarcosLima 15081Peru Natural History museum Universidad Nacional Mayor de San MarcosLima 15072Peru Applied phytology Laboratory Faculty of Biological SciencesUniversidad Nacional Mayor de San MarcosLima 15081Peru Department of Statistics Faculty of Mathematical SciencesUniversidad Nacional Mayor de San MarcosLima 15081Peru Department of chemical and Biological Sciences Universidad de las Américas PueblaSan Andrés Cholula CP Cholula CP 72810Mexico

A large fire of 233 ha in Huascarán National park in peru provided an opportunity to compare plant and bird responses in burned and nearby unburned zones of the puna. Heights and live diameters of flagship puya raimondii rosettes(assigned to four broad developmental phases), plant communities(66 species in 24 families and nine growth forms) and bird communities(77 species in six trophic guilds) were monitored after the fire. Although no mortality was observed, puya raimondii plants were affected by the fire, losing approximately 60% of their photosynthetic area across all developmental phases, but recovered quickly during the first two years after fire. The comparison of puya rosette recovery after fire was complicated by the changes in live rosette diameter for unburned plants, which showed plasticity of photosynthetic area linked to seasonal and annual fluctuations in precipitation in this relatively dry environment(decreased by 26% for mature adult plants over the study period). Fire caused an immediate change in the density, biomass and composition of vegetation. Although the species present remained similar, their abundances changed significantly immediately after the fire, with notable reductions in dominant tussock grasses. This provided opportunities for other plants, resulting in higher postfire diversity of plant species, genera, families and growth forms. In turn, the changes in vegetation after fire affected the composition of birds according to their trophic guild. Granivores largely disappeared,generalists were mostly unaffected, and other guilds showed a more complex response. As the vegetation recovered, most displaced birds returned within approximately one year.

关键词： Burning plant biomass Trophic guilds Andes Giant rosette plants

Single atom cu-N-c catalysts for the electro-reduction of cO_(2) to cO assessed by rotating ring-disc electrode

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Journal of Energy chemistry 2024年第1期88卷 169-182,I0004页

作者： S.pérez-Rodríguez m.Gutiérrez-Roa c.Giménez-Rubio D.Ríos-Ruiz p.Arévalo-cid m.V.martínez-Huerta A.Zitolo m.J.Lázaro D.Sebastián Instituto de carboquímica(cSIc) Miguel Luesma Castán 450018 ZaragozaSpain Instituto de catálisis y petroleoquímica(cSIc) Marie Curie 228049 MadridSpain Synchrotron SOLEIL L’Orme des MerisiersDépartementale 12891190France

The electrochemical cO_(2) reduction reaction(cO_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped carbon xerogel(cu-N-c) are successfully developed varying the copper amount and the nature of the copper precursor, for the efficient cO_(2)RR. The electrocatalytic performance of cu-N-c materials is assessed by a rotating ring-disc electrode(RRDE), technique still rarely explored for cO_(2)RR. For comparison, products are also characterized by online gas chromatography in a H-cell. The as-synthesized cu-Nc catalysts are found to be active and highly cO selective at low overpotentials(from -0.6 to -0.8 V ***) in 0.1 m KHcO_(3), while H_(2) from the competitive water reduction appears at larger overpotentials(-0.9 V vs. RHE). The optimum copper acetate-derived catalyst containing cu-N_(4) moieties exhibits a cO_(2)-to-cO turnover frequency of 997 h^(-1) at -0.9 V vs. RHE with a H_(2)/cO ratio of 1.8. These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from cO_(2)RR.

关键词： cu-N-c carbon xerogel Rotating ring disc electrode carbon dioxide reduction reaction carbon monoxide

comparative analysis of microstructure,mechanical,and corrosion properties of biodegradable mg-3Y alloy prepared by selective laser melting and spark plasma sintering

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Journal of magnesium and Alloys 2024年第4期12卷 1496-1510页

作者： p.minárik m.Zemková S.Šašek J.Dittrich m.Knapek F.Lukáˇc D.Koutný J.Jaroš R.Král Faculty of mathematics and physics Charles UniversityKe Karlovu 5Praha 12116Czech Republic research centre University ofŽilinaUniverzitná8215/1Žilina 01026Slovakia Institute of plasma physics of the czech Academy of Sciences Za Slovankou 1782/318200 Praha 8Czech Republic Institute of machine and Industrial Design Brno University of TechnologyTechnická2896/2Brno 61669Czech Republic

This work explored possibilities of biodegradable magnesium alloy mg-3Y preparation by two modern powder metallurgy techniques–spark plasma sintering(SpS)and selective laser melting(SLm).The powder material was consolidated by both methods utilising optimised parameters,which led to very low porosity(∼0.3%)in the SLm material and unmeasurably low porosity in the SpS *** main aim of the study was the thorough microstructure characterisation and interrelation between the microstructure and the functional properties,such as mechanical strength,deformability,and corrosion *** materials showed comparable strength of∼110 mpa in tension and compression and relatively good deformability of∼9%and∼21%for the SLm and SpS materials,*** corrosion resistance of the SpS material in 0.1 m Nacl solution was superior to the SLm one and comparable to the conventional extruded *** digital image correlation during loading and the cross-section analysis of the corrosion layers revealed that the residual porosity and large strained grains have the dominant negative effect on the functional properties of the SLm *** the other hand,one of the primary outcomes of this study is that the SpS consolidation method is very effective in the preparation of the W3 biodegradable alloy,resulting in material with convenient mechanical and degradation properties that might find practical applications.

关键词： magnesium Yttrium powder metallurgy microstructure mechanical strength corrosion resistance