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Rietveld refinement and optical properties of srWO_4:Eu^(3+) powders prepared by the non-hydrolytic sol-gel method

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Journal of Rare Earths 2015年第2期33卷 113-128页

作者： P.F.s.Pereira I.c.Nogueira E.longo E.J.Nassar I.l.V.Rosa l.s.cavalcante chemistry Institute University of the State of Sao Paulo Julio de Mesquita Filho-UNESP Francisco DegniAraraquara-SP 14800-900 Brazil lIEc-chemistry Department Federal University of Sao Carlos Via Washington Luis Km 235Sao Carlos-SP 13565-905 Brazil University of Franca-UNIFRAN Via Dr.Armando Sales de OliveiraNo.201 Franca-SP 14404-600 Brazil ccN-DQ-GERATEc University of the State of Piauí Joao Cabral 2231 P.O.Box 391Terezina PI 64002-150 Brazil

We investigated the effect of annealing time on the structure and optical properties of sr WO4：Eu^3＋ powders prepared by the non-hydrolytic sol-gel method and heat treated at 800 ℃ for 2,4,8 and 16 *** and differential thermal analyses revealed that sr WO4：Eu^3＋ powders were obtained at about 800 ℃.X-ray diffraction patterns and Rietveld refinement data confirmed that all powders had a scheelite-type tetragonal ***-Raman and Fourier transform infrared spectra indicated structural order at short range and anti-symmetric stretching vibrations of O-W-O bonds associated with tetrahedral[WO4]*** properties were investigated by ultraviolet-visible（UV-vis）diffuse reflectance,and photoluminescence（Pl）data which provided the evolution of quantum efficiency（η）and lifetime（τ）.UV-vis spectroscopy evidenced intermediate energy levels within the band gap of sr WO4：Eu^3＋ *** properties validated that the Eu^3＋ electric-dipole（^5D0→^7F2）transition in Pl emission spectra was dominant which proved that Eu^3＋ ions were positioned in a site without an inversion center.[（^5D0→^7F2）/（^5D0→^7F1）]band ratios showed that Eu^3＋ ions were located in a low symmetry *** Pl emission,ηandτproved the dependence on the annealing time in the behavior of sr WO4：Eu3＋powders with a higher relative emission Pl intensity as well as higherηandτvalues related to other samples when heat treated at 800℃ for 8 h.

关键词： srWO4 Rietveld refinement optical band gap Eu^(3+) +-rare earth luminescence

Anti-amyloid antibodies in Alzheimer’s disease: what did clinical trials teach us?

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Neural Regeneration Research 2025年第4期20卷 1092-1093页

作者： Danko Jeremic lydia Jiménez-Díaz Juan D.Navarro-lópez NeuroPhysiology&Behavior lab University of Castilla-La ManchaBiomedical Research Center(CRIB)School of Medicine of Ciudad RealCiudad RealSpain

Although many causes of Alzheimer’s disease(AD)may exist,both the original amyloid cascade and tau hypotheses posit that abnormal misfolding and accumulation of amyloid-β(Aβ)and tau protein is the central event causing the ***,that conclusion could be only partly true,and there is conflicting evidence about the role of both proteins in AD,being able to precede and influence one *** researchers argue that these proteins are mere executors rather than primary causes of ***,there have been continuing refinements of both hypotheses,with alternative explanations proposed.Aβand tau proteins may be independently involved in specific neurotoxic pathways;yet there may be other crucial processes going on in early ***,accumulating evidence suggests that Aβand tau act synergistically,rather than additively in disease onset(Jeremic et al.,2021,2023a).

关键词： amyloid Alzheimer additive

Electronic structure of correlated topological insulator candidate YbB6 studied by photoemission and quantum oscillation

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chinese Physics B 2020年第1期29卷 70-75页

作者： T Zhang G li s c sun N Qin l Kang s H Yao H M Weng s K Mo l li Z K liu l X Yang Y l chen state Key laboratory of low Dimensional Quantum Physics Department of PhysicsTsinghua UniversityBeijing 100084China Department of Physics University of MichiganAnn ArborMI 48109USA Beijing National laboratory for condensed Matter Physics and Institute of Physics Chinese Academy of SciencesBeijing 100190China National laboratory of solid state Microstructures&Department of Materials science and Engineering Nanjing UniversityNanjing 210093China collaborative Innovation center of Quantum Matter BeijingChina songshan lake Materials laboratory Dongguan 523808China cAs center for Excellence in Topological Quantum computation Beijing 100190China Physical science laboratory Huairou National Comprehensive Science CenterBeijing 101400China Advanced light source Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA school of Physical science and Technology ShanghaiTech University and CAS-Shanghai Science Research CenterShanghai 201210China shanghaiTech laboratory for Topological Physics Shanghai 200031China Frontier science center for Quantum Information Beijing 100084China Department of Physics Clarendon LaboratoryUniversity of Oxford Parks RoadOxford OX13PUUK

Angle-resolved photoemission spectroscopy(ARPEs)and torque magnetometry(TM)measurements have been carried out to study the electronic structures of a correlated topological insulator(TI)candidate Yb *** observed clear surface states on the[001]surface centered at theГ^- and М^- points of the surface Brillouin ***,the fermiology revealed by the quantum oscillation of TM measurements agrees excellently with ARPEs ***,the band structures we observed suggest that the band inversion in Yb B6 happens between the Yb5 dand B2bands,instead of the Yb5dand Yb4fbands as suggested by previous theoretical investigation,which will help settle the heavy debate regarding the topological nature of samarium/ytterbium hexaborides.

关键词： topological insulator electronic structure surface states

cost-effective distributed FTFc for uncertain nonholonomic mobile robot fleet with collision avoidance and connectivity preservation

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Journal of Automation and Intelligence 2023年第1期2卷 42-50页

作者： Xiucai Huang Zhengguo li Frank l.lewis chongqing Key laboratory of Intelligent Unmanned systems School of AutomationChongqing UniversityChongqing400044China The sRO Department Institute for Infocomm Research138632Singapore The University of Texas at Arlington ArlingtonTX 76118USA

In this paper,the fault-tolerant formation control(FTFc)problem is investigated for a group of uncertain nonholonomic mobile robots with limited communication ranges and unpredicted actuator faults,where the communication between the robots is in a directed one-to-one *** order to guarantee the connectivity preservation and collision avoidance among the robots,some properly chosen performance functions are incorporated into the controller to per-assign the asymmetrical bounds for relative distance and bearing angle between each pair of adjacent mobile ***,the resultant control scheme remains at a costeffective level because its design does not use any velocity information from neighbors,any prior knowledge of system nonlinearities or any nonlinear approximator to account for them despite the presence of modeling uncertainties,unknown external disturbances,and unexpected actuator ***,each follower is derived to track the leader with the tracking errors regarding relative distance and bearing angle subject to prescribed transient and steady-state performance guarantees,***,all the closed-loop signals are ensured to be ultimately uniformly ***,a numerical example is simulated to verify the effectiveness of this methodology.

关键词： Fault-tolerant formation control Nonholonomic mobile robot connectivity preservation collision avoidance

The propagation of shape changing soliton in a nonuniform nonlocal media

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chinese Physics B 2013年第8期22卷 462-480页

作者： l. Kavitha c. lavanya s. Dhamayanthi N. Akila D. Gopi Department of Physics Periyar UniversitySalem-636 011 India The Abdus salam International center for Theoretical Physics Trieste Italy center for Nanoscience and Nanotechnology Periyar UniversitySalem-636 011 India Department of chemistry Periyar UniversitySalem-636 011 India

Magnetization dynamics in uniformly magnetized ferromagnetic media is studied by using landau-lifshitz-Gilbert equation. The nonlinear evolution equation is integrable with site-dependent and biquadratic exchange interaction by means of landau-lifshitz （ll） equation which is well understood. In the present work, we construct the exact solitary solutions of the nonlinear evolution equation, particularly, we employ the modified extended tangent hyperbolic function method. We show the shape changing property of solitons for the given integrable system in the presence of damping as well as inhomogeneities.

关键词： solitons classical spin models Maxwell equations nonlinear dynamics

Molecular modeling of the octacoordinated tetracarbonato-Nd(III), [Nd(cO_3)_4]^(5-), complex and its nonacoordinated fluoro- and aquo-adducts

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Journal of Rare Earths 2010年第6期28卷 847-853页

作者： s. P. sinha Alfredo M. simas Gustavo l. c. Moura scientific Research & Development Departamento de Quimica Fundamental CCEN Universidade Federal de Pernambuco

Theoretical investigation on the structures of the octacoordinated [Nd(cO3)4]5-and the nonacoordinated [Nd(cO3)***2]5-complexes, using the sPARKlE parameters of the lanthanides within MOPAc, revealed that they possessed dodecahedral and square antiprismatic structures respectively with an average Nd-O distance of 0.249 nm. These structures and the Nd-O distances agreed well with those experimentally found in the crystal structures. Replacing the water molecule with a fluoride ion or a mondentatecarbonato ligand resulted in a nonacoordinated distorted square antiprismatic structures where the trans-carbonato groups were twisted. The corresponding decacoordinated structures with two fluoride ions or a bidentatecarbonato group, [Nd(cO3)4·F2]7-and [Nd(cO3)5]7-, were also investigated. In both cases considerable twisting of the transcarbonato groups was observed.

关键词： lanthanides theoretical molecular models octacoordination carbonato complexes adducts MOPAc sPARKlE rare earths

Expert perspectives on GIs use in spanish geographic education

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International Journal of Digital Earth 2022年第1期15卷 1204-1218页

作者： I.J.Buzo-sánchez c.Mínguez M.l.De lázaro-Torres IEs san Roque BadajozSpain Geography Department Universidad Complutense de MadridMadridSpain Geography Department UNEDMadridSpain

The emergence of new technological tools for territorial analysis,such as cloud-based GIs,or GIs viewers,compels us to closely examine its usefulness in geographic education. specifically,it raises the professors and teachers’ questions: what to teach? how to teach? and what will students learn? This research responds to these three questions by interviewing spanish experts who know how to use these tools to teach geography at university and secondary school levels. The Delphi technique was applied to achieve this,which established consensus and led to the following results from experts’ own experience: (1) that GIs help to understand territory in an experiential and non-memoristic way and (2) they enable the development of spatial thinking. This paper concludes that changes in methodologies and integrate technical knowledge into teacher training are needed.

关键词： Geography Delphi GIs competencies spatial thinking

cr-induced fusion reactions to synthesize superheavy elements

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Nuclear science and Techniques 2024年第5期35卷 122-130页

作者： s.Madhu H.c.Manjunatha N.sowmya B.M.Rajesh l.seenappa R.s.susheela Department of Physics R V College of EngineeringBangalore 560074India Visvesvaraya Technological University BelagaviKarnataka 590018India Department of Physics Government First Grade CollegeSrinivasapurKarnataka 563135India Department of Physics Government First Grade CollegeDevanahallyKarnataka 562110India Department of Physics Government First Grade CollegeMulbagalKarnataka 563131India Department of Physics Government First Grade collegeNanjangudOoty RoadMysore 571301India

We investigated ^(50,52-54)cr-induced fusion reactions for the synthesis of the superheavy element in the 104≤Z≤122 *** cross sections produced in this investigation using ^(54)cr projectiles were compared with those obtained in prior *** estimated cross sections from this analysis are consistent with the findings of prior *** the current study,the predicted cross section was found to be 42fb at 236 MeV for ^(53)cr+^(243)Am,23.2 fb at 236 MeV for ^(54)cr+^(247)cm,95.6 fb at 240 MeV for ^(53)cr+248Bk,and 1.33 fb at 242 MeV for ^(53)cr+***,these projected cross sections with excitation energy and beam energy will be useful in future cr-induced fusion reaction investigations.

关键词： Fusion cross sections compound nucleus formation probability survival probability Evaporation residue cross sections

New insights into the hardening and pitting corrosion mechanisms of thermally aged duplex stainless steel at 475℃:A comparative study between 2205 and 2101 steels

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Journal of Materials science & Technology 2022年第3期98卷 123-135页

作者： R.silva G.s.Vacchi c.l.Kugelmeier I.G.R.santos A.A.Mendes Filho D.c.c.Magalhães c.R.M.Afonso V.l.sordi c.A.D.Rovere Munir Rachid corrosion laboratory Department of Materials EngineeringFederal University of São CarlosRodovia Washington Luis Km 23513565-905 São CarlosSPBrazil Engineering Modeling and Applied Social Sciences Center(CECS)Federal University of ABCAvenida dos Estados 500109210580 Santo AndréSPBrazil Federal University of são carlos Graduate Program in Materials Science and EngineeringBrazil

In this study,the relationship between spinodal decomposition and the formation of Ni-rich clusters and G-phase in the ferrite on hardening and pitting corrosion of two thermally aged duplex stainless steels(Dsss)at 475℃was *** indicate that,for 2205 Dss,pitting corrosion behavior is influenced by the presence and size of G-phase precipitates for longer aging times,but this contribution is masked by the advanced stage of spinodal decomposition in the ferritic *** the other hand,for 2101 Dss,the formation of cr-richer nitrides impairs pitting corrosion resistance more than spinodal decomposition.

关键词： Duplex stainless steel spinodal decomposition G-phase precipitation Pitting corrosion Hardening