检索结果-南通市图书馆

Impact of device resistances in the performance of graphene‑based terahertz photodetectors

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Optoelectronics 2024年第2期17卷 87-97页

作者： O.Castelló Sofía m.López Baptista K.Watanabe T.Taniguchi e.Diez j.e.Velázquez-pérez Y.m.meziani j.m.Caridad j.A.Delgado-Notario Department of Applied physics University of Salamanca37008 SalamancaSpain Unidad de excelencia en Luz y materia estructurada(LUmeS) University of Salamanca37008 SalamancaSpain Research Center for electronic and Optical materials National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan Research Center for materials Nanoarchitectonics National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan Nanotechnology Group USAL-NanolabUniversity of Salamanca37008 SalamancaSpain

In recent years,graphene field-effect-transistors(GFeTs)have demonstrated an outstanding potential for terahertz(THz)photodetection due to their fast response and *** features are essential to enable emerging THz applications,including 6G wireless communications,quantum information,bioimaging and ***,the overall performance of these photodetectors may be utterly compromised by the impact of internal resistances presented in the device,so-called access or parasitic *** this work,we provide a detailed study of the influence of internal device resistances in the photoresponse of high-mobility dual-gate GFeT *** dual-gate architectures allow us to fine tune(decrease)the internal resistance of the device by an order of magnitude and consequently demonstrate an improved responsivity and noise-equivalent-power values of the photodetector,*** results can be well understood by a series resistance model,as shown by the excellent agreement found between the experimental data and theoretical *** findings are therefore relevant to understand and improve the overall performance of existing high-mobility graphene photodetectors.

关键词： Graphene THz photodetector Field-effect transistor plasmonic

Consumer transparency in the production chain for plant varieties produced using new genomic techniques

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

aBIOTeCH 2024年第2期5卷 239-246页

作者： j.m.Lukasiewicz C.C.m.van de Wiel L.A.p.Lotz m.j.m.Smulders Wageningen University&Research P.O.Box 386NL-6700 AJ WageningenThe Netherlands

plants edited with new genomic techniques(NGTs)currently fall under the Genetically modified Organisms Directive(2001/18/eC)in the european *** the proposal of the european Commission,NGT plants are partially exempted from the regulations of this *** proposal makes a distinction between two categories of NGT plants:NGT-1 and ***-1 category plants are considered equal to plants obtained through conventional breeding *** plants will not be labelled for the consumer,although they will be labelled as ***-2 category plants may be labelled with additional information as a positive *** of seeds of varieties made with gene editing,but not the products,would mean that most steps in the production chain are transparent,but not the last step towards ***“right to know”and increasing knowledge of gene-edited food is a common theme in food labelling towards ***,we describe current labelling regimes and registers and how these may be applied to provide transparency on gene-edited products to ***,we also look into consumer studies,which indicate a greater acceptance of gene-edited food among consumers,especially when additional benefits such as sustainability are mentioned.

关键词： Labelling New genomic techniques Consumer transparency plant products

europium recovery process by means of polymeric nanoparticles functionalized with acrylic acid,curcumin and fumaramide

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

journal of Rare earths 2024年第10期42卷 1950-1959页

作者： p.A.martínez-montoya j.m.del Río A.de j.morales-Ramirez m.Corea escuela Superior de Ingeniería Química e Industrias extractivas ESIQIE-IPNDepartamento de Ingeniería Metalúrgica UPALM S/N Col.Lindavista escuela Superior de Ingenieria Química e Industrias extractivas ESIQIE-IPNLaboratorio de Investigación en Polímeros y NanomaterialesUPALM S/N Col.Lindavista Centra de Investigación e Innovación Tecnológica CIITEC-IPNCda.de CECATIs/n

polymeric nanoparticles of poly(methyl methacrylate) were obtained by emulsion polymerization techniques in a proce ss of two *** particles were functionalized with acrylic acid,curcumin,and fumaramide and three series of polymeric particles were *** incorporation of functional groups was confirmed by Fourier transform-infrared spectrosocopy(FT-IR) and ultraviolet-visible(UV-Vis) *** spherical morphology of particles with an average diameter of 100 nm was observed by scartning electron microscopy(Sem).The polymeric materials were used for recovery of [eu]from synthetic *** nanoparticles show excellent chelation capacity to trap rare-earth ions,because they recover more than 85% of [eu] at pH of *** images of Sem after extraction process show arrays between particles with larger average particle sizes to 1.5 *** addition,the particles have a good stripping capacity,exceeding 50% of it,maintaining their homogeneity in morphology and good stability in dispersion for the recovery and stripping processes.A pseudo-second model order is obtained for the extraction and stripping processes while the best results of stripping process are obtained at pH of6.

关键词： Chelating effect emulsion polymerization extraction process Rare earths Stripping process [eu]recovery

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

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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

CO oxidation under lean and stoichiometric conditions over ceriazirconia with very low metal contents(Cu,Co,Ag and pt)

在线全文

学校读者我要写书评

暂无评论

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

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

在线全文

学校读者我要写书评

暂无评论

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

Background removal from global auroral images:Data-driven dayglow modeling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

earth and planetary physics 2024年第1期8卷 247-257页

作者： A.Ohma m.madelaire K.m.Laundal j.p.Reistad S.m.Hatch S.Gasparini S.j.Walker Birkeland Centre for Space Science Department of Physics and TechnologyUniversity of BergenBergenNorway

Global images of auroras obtained by cameras on spacecraft are a key tool for studying the near-earth ***,the cameras are sensitive not only to auroral emissions produced by precipitating particles,but also to dayglow emissions produced by photoelectrons induced by *** emissions and scattered sunlight can contribute to the background *** fully utilize such images in space science,background contamination must be removed to isolate the auroral *** we outline a data-driven approach to modeling the background intensity in multiple images by formulating linear inverse problems based on B-splines and spherical *** approach is robust,flexible,and iteratively deselects outliers,such as auroral *** final model is smooth across the terminator and accounts for slow temporal variations and large-scale asymmetries in the *** demonstrate the model by using the three far ultraviolet cameras on the Imager for magnetopause-to-Aurora Global exploration(ImAGe)*** method can be applied to historical missions and is relevant for upcoming missions,such as the Solar wind magnetosphere Ionosphere Link explorer(SmILe)mission.

关键词： aurora dayglow modeling global auroral images far ultraviolet images dayglow removal

BaTiO3 solid solutions co-doped with Gd3+ and eu3+:Synthesis,structural evolution and dielectric properties

在线全文

学校读者我要写书评

暂无评论

journal of Rare earths 2024年第10期42卷 1920-1926页

作者： R.martínez-López m.pérez-Labra j.A.Romero-Serrano F.R.Barrientos-Hernández m.Reyes-pérez m.I.Valenzuela-Carrillo G.Urbano-Reyes V.e.Reyes-Cruz G.I.Dávila-pulido Academic Area of earth Sciences and materials Autonomous University of Hidalgo State metallurgy and materials Department ESIQIE-IPNUPALM Autonomous University of Coahuila Boulevard Adolfo López Mateos S/n

In this paper,the synthesis,structural evolution,and dielectric properties of BaTiO3solid solutions codoped with rare earth elements(Gd3+and eu3+) prepared using the solid-state reaction method are *** pure precursor powders of BaCl3,TiO2,Gd2O3,and eu2O3were mixed in stoichiometric proportions,ground in an agate mortar before being uniaxially pressed at 250 mpa and sintered at 1300℃ in air atmosphere for 6 h to obtain Ba1-3xGd2xTi1-3xeu4xO3（x=0,0.0015,0.01 and0.1）.X-ray diffraction（XRD） and Rietveld's refinement results reveal the crystal phase ferroelectric tetragonal BaTiO3for the samples with x=0,0.0015 and 0.01, as well as a consistent increment in the lattice parameters caused by the *** solubility limit of Gd3+and eu3+in the BaTiO3structure is reached for the sample with x>0.01,and the orthorhombic eu2TiO5and monoclinic BaTi2O5secondary phases were *** Raman results show the characteristic peaks of ferroelectric tetragonal BaTiO3around 716 cm-1（LO of A1 symmetry）,515 cm-1（TO of A1 symmetry）,and 305 cm-1（B1）.The maximum relative permittivity measured at 1 kHz was recorded to be 6151.8 for the sample with x=0.0015,and a decrease in the Curie temperature to 105℃ with respect to the undoped sample was *** punctual microanalysis for the samples with x=0.0015,0.01,and 0.1 reveals grains composed of Ba,Ti,O,Gd,and eu homogeneously distributed in the *** Ba/Ti ratios for samples with x=0.0015,0.01 and 0.1 are 2.86,2.91,and 0.68,respectively,indicating substitution at the Ti site for samples with x=0.0015 and 0.01 and a substitution at the Ba site for the sample with x=0.1.

关键词： BaTiO3 Doping europium Gadolinium Rare earths Synthesis

In vivo and in vitro study of resorbable magnesium wires for medical implants:mg purity,surface quality,Zn alloying and polymer coating

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

journal of magnesium and Alloys 2024年第6期12卷 2472-2488页

作者： K.Tesar j.Luňácková m.jex m.Žaloudková R.Vrbová m.Bartoš p.Klein L.Vištejnová j.Dušková e.Filová Z.Sucharda m.Steinerová S.Habr K.Balík A.Singh Department of materials Faculty of Nuclear Sciences and Physical EngineeringCzech Technical University in PragueTrojanova 13Prague 12000Czech Republic Institute of physics Czech Academy of SciencesNa Slovance 2Prague 18221Czech Republic Institute of Dental medicine First Faculty of MedicineCharles University and General University Hospital in PragueKaterinská32Prague 12801Czech Republic Department of physics Faculty of Nuclear Sciences and Physical EngineeringCzech Technical University in PragueBrehová7Prague 11519Czech Republic Department of Composites and Carbon materials Institute of Rock Structure and MechanicsCzech Academy of SciencesV Holešovickách 41Prague 18209Czech Republic Institute of Anatomy First Faculty of MedicineCharles UniversityU Nemocnice 3Prague 12800Czech Republic Biomedical Center Faculty of Medicine in PilsenCharles UniversityAlej Svobody 76Pilsen 32300Czech Republic Department of pathological physiology Faculty of Medicine in PilsenCharles UniversityAlej Svobody 7632300 PilsenCzech Republic Department of Histology and embryology Faculty of Medicine in PilsenCharles UniversityAlej Svobody 7632300 PilsenCzech Republic Institute of pathology First Faculty of MedicineCharles University and General University Hospital in PragueStudnickova 2Prague 12800Czech Republic Department of Biomaterials and Tissue engineering Institute of PhysiologyCzech Academy of SciencesVidenska 1083Prague 14200Czech Republic Research Center for Structural materials National Institute for Materials Science1-2-1 SengenTsukuba 305-0047Japan

magnesium is an excellent material in terms of biocompatibility and its corrosion products can serve as an active source for new bone ***,localized corrosion and H_(2)generation limit the potential of mg-based *** low-alloyed mg-Zn wires can strongly reduce problems with large H_(2)bubbles and improve the mechanical properties considerably while maintaining excellent long-term *** pickling and a polymer coating can be effectively used to lower the rate of in vivo *** this work,microstructural,mechanical,and in vitro characterization of 250μm and 300μm extruded wires made from ultra-pure mg,commercially pure mg,mg-0.15Zn,mg-0.4Zn and mg-1Zn was ***,mg-0.4Zn wires together with a variant coated with a copolymer of L-lactide andε-caprolactone were tested in vivo on artificially damaged Wistar rat *** on the observed mg-induced osteogenesis,polymer-coated mg wires with a small addition of Zn are a perspective material for bone-support applications,such as cerclage and fixation wires.

关键词： magnesium Resorbable mg wire mg-Zn implant degradation Biocompatibility study Zn grain boundary segregation