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Biaxial versus uniaxial strain tuning of single-layer MoS_(2)

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Nano Materials Science 2022年第1期4卷 44-51页

作者： Felix Carrascoso Riccardo Frisenda Andres Castellanos-Gomez Materials Science Factory Instituto de Ciencia de Materiales de Madrid(ICMM-CSIC)28049Madrid Spain

Strain engineering has arisen as a powerful technique to tune the electronic and optical properties of twod imensional semiconductors like molybdenum disulfide(MoS_(2)).Although several theoretical works predicted that biaxial strain would be more effective than uniaxial strain to tune the band structure of MoS_(2),a direct experimental verification is still missing in the *** we implemented a simple experimental setup that allows to apply biaxial strain through the bending of a cruciform polymer *** used the setup to study the effect of biaxial strain on the differential reflectance spectra of 12 single-layer MoS_(2)flakes finding a redshift of the excitonic features at a rate between-40 meV/%and-110 meV/%of biaxial *** also directly compare the effect of biaxi al and uniaxial strain on the same single-layer MoS_(2)finding that the biaxial strain gauge factor is 2.3 times larger than the uniaxial strain one.

关键词： finding layer gauge

Heterogeneous catalysts with programmable topologies generated by reticulation of organocatalysts into metal-organic frameworks:The case of squaramide

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Nano Research 2021年第2期14卷 458-465页

作者： Anna Broto-Ribas Claudia Vignatti Alicia Jimenez-Almarza Javier Luis-Barrera Zahra Dolatkhah Felipe Gandara Inhar Imaz Ruben Mas-Balleste Jose Aleman Daniel Maspoch Catalan Institute of Nanoscience and Nanotechnology(ICN2) CSIC and The Barcelona Institute of Science and Technology08193 BarcelonaSpain Inorganic Chemistry Department Modulo 7Universidad Autonoma de Madrid28049 MadridSpain Organic Chemistry Department Modulo 1Universidad Autonoma de Madrid28049 MadridSpain Materials Science Factory Instituto de Ciencia de Materiales de Madrid(ICMM)Consejo Superior de Investigaciones Cientificas(CSIC)Calle Sor Juana Ines de la Cruz328049 MadridSpain Institute for Advanced Research in Chemical Sciences(IAdChem) Campus Universidad Autonoma de Madrid28049 MadridSpain Institucio Catalana de Recerca i Estudis Avangats(ICREA) 08100 BarcelonaSpain

A well-established strategy to synthesize heterogeneous,metal-organic framework(MOF)catalysts that exhibit nanoconfinement effects,and specific pores with highly-localized catalytic sites,is to use organic linkers containing organocatalytic ***,we report that by combining this linker approach with reticular chemistry,and exploiting three-dimensioanl(3D)MOF-structural data from the Cambridge Structural Database,we have designed four heterogeneous MOF-based catalysts for standard organic *** programmable MOFs are isoreticular versions of pcu IRMOF-16,feu UiO-68 and pillared-pcu SNU-8X,the three most common topologies of MOFs built from the organic linker p.p'-terphenyldicarboxylic acid(tpdc).To synthesize the four squaramide-based MOFs,we designed and synthesized a linker,4,4’-((3,4-dioxocyclobut-1-ene-1,2-diyl)bis(azanedyil))dibenzoic acid(Sq_tpdc),which is identical in directionality and length to tpdc but which contains organocatalytic squaramide *** were chosen because their immobilization into a framework enhances its reactivity and stability while avoiding any self-quenching ***,the four MOFs share the same organocatalytic squaramide moiety,but confine it within distinct pore *** then evaluated these MOFs as heterogeneous H-bonding catalysts in organic transformations:a Friedel-Crafts alkylation and an epoxide *** of them exhibited good performance in both reactions but all showed distinct catalytic profiles that reflect their structural differences.

关键词： reticular chemistry metal-organic frameworks H-bond catalysis squaramide Friedel-Cratts epoxide ring-opening

Individual and demographic responses of a marsh bird assemblage to habitat loss and subsequent restoration

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Avian Research 2020年第1期11卷 25-33页

作者： Ruben Moreno-Opo Monticola Ornithological Group Faculty of BiologyUniversity Autonoma of MadridMadrid 28049Spain Deputy Directorate on Biodiversity Ministry for the Ecological TransitionMadrid 28071Spain

Background: The alteration and loss of habitats are two of the main threats that biodiversity conservation is cur?rently facing up to. The present study describes the effects of a perturbation and restoration in a reedbed habitat on a bird assemblage. We studied the bird community of a wetland of central Spain between 1995 and 2009, during which time an anthropic perturbation altered the original structure of the habitat;subsequently, as a result of restoration works, the habitat returned to its original ***: We evaluated the effects on six population and physical parameters of the birds at three different phases of their life cycles(breeding, wintering and post?breeding migration seasons) before, during and after the habitat alteration. GLM was used to analyze the influence of three independent variables(year, perturbation phase and temperature).Results: The relative abundance and the species richness values decreased when habitat was altered, but then recovered as a result of the regeneration works. This pattern was the clearest amongst specialist species. Breeding success also declined during the perturbation phase and then increased;likewise, the sex ratio changed given that the proportion of male birds increased when habitat was altered. These results are discussed in relation to changes on availability of resources in altered habitats, to the adaptive mechanisms in the exploitation of ecological requirements and to the selection of optimum and sub?optimum habitats by generalist and specialist ***: Ecosystem restoration can favour the recovery of population indexes of specialist passerines, although it depends on the efficiency of the type of restoration activity performed and on the complexity of the habitat.

关键词： Habitat loss Land-use planning Marsh Restoration Ringing station Reedbed

How to make the end of a gene,the simple way

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BIOCELL 2022年第6期46卷 1453-1457页

作者： KAREL H.M.VAN WELY Centro Nacional de Biotecnología/CSIC Madrid28049Spain

Transcription termination of nearly all protein-coding genes in mammals requires 3’end processing by a multiprotein complex that will cleave and polyadenylate the messenger RNA *** a variety of enzyme complexes intervene,3’end processing was thought to be fundamentally complex and subject to a multitude of regulatory *** possibility to select just one out of several polyadenylation sites,in particular,has caused much questioning and *** appear to be separate mechanisms however can be combined into a defined set of rules,allowing for a relatively simple interpretation of 3’end ***,readiness of the terminal exon splice site determines when a transcript reaches the maturity to select a nearby polyadenylation *** pausing then acts in concert,extending the timeframe during which the transcription complex is close to polyadenylation *** RNA polymerase pausing is governed by the same type of sequences in bacteria and metazoans,mammalian transcription termination resembles its prokaryote counterpart more than generally thought.

关键词： RNA transcription RNA polymerase II pausing Splicing Termination Polyadenylation

Strain-induced band gap engineering in layered TiS3

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Nano Research 2018年第1期11卷 225-232页

作者： Robert Biele Eduardo Flores Jose Ramon Ares Carlos Sanchez Isabel J. Ferrer Gabino Rubio-Bollinger Andres Castellanos-Gomezs Roberto D'Agosta Nano-Bio Spectroscopy Group and European Theoretical Spectroscopy Facility (EFSF) Universidad del Pals Vasco 20018 San Sebastidn Spain Materials of Interest in Renewable Energies Group (MIRE Group) Dpto. de Fisica de Materiales Universidad Aut6noma de Madrid 28049 Madrid Spain Instituto de Ciencia de Materiales "Nicolds Cabrera" Campus de Cantoblanco 28049 Madrid Spain Dpto. de Ffsica de la Materia Condensada Condensed Matter Physics Center (IFIMAC) Universidad Aut6noma de Madrid Campus de Cantoblanco 28049 Madrid Spain Instituto de Ciencia de los Materiales de madrid (ICMM-CSIC) Cantoblanco 28049 Madrid Spain IKERBASQUE Basque Foundation for Science 48013 Bilbao Spain

By combining ab initio calculations and experiments, we demonstrate how the band gap of the transition metal trichalcogenide TiS3 can be modified by inducing tensile or compressive strain. In addition, using our calculations, we predicted that the material would exhibit a transition from a direct to an indirect band gap upon application of a compressive strain in the direction of easy electrical transport. The ability to control the band gap and its nature could have a significant impact on the use of TiS3 for optical applications. We go on to verify our prediction via optical absorption experiments that demonstrate a band gap increase of up to 9% （from 0.99 to 1.08 eV） upon application of tensile stress along the easy transport direction.

关键词： band gap engineering titanium trisulfide 2-D materials strain

Synthesis of a pair of novel receptors and their properties of enantioselective recognition for amino acid zwitterions

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Chinese Journal of Chemistry 1999年第5期17卷 508-515,427页

作者：陆国元刘芳何卫江王志林胡宏纹 Department of Chemistry Nanjing University Nanjing Jiangsu 210)93 China Departament de Quimica Organica Universidad Autonoma de Madrid Madrid 28049 Spain

A pair of artificial enantiotopic receptors la and lb composed of (S,S) or (R,R) chiral bicyclic guanidinium, azacrown ether and (t-butyldiphenylsilyloxy) methyl group for amino acid zwitterions have been synthesized. The liquid-liquid competition experiments and 1 H NMR studies indicate that the receptor 1a with (S, S) configuration and 1b with (R,R) configuration selectively recognize L- and D-aromatic amino acids & respectively.

关键词： Enantioselective Recognition amino acid zwitterions artificial receptor

Magnetostriction Dependence of the Relaxation Frequency in the Magnetoimpedance Effect for Amorphous and Nanocrystalline Ribbons

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Chinese Physics Letters 2002年第12期19卷 1870-1873页

作者： M.L.Sanchez M.Vazquez 等 DepartamentodeFisica FacultaddeCienciasCalveSotelos/n33007-OviedoSpain InstitutodeCienciadeMateriales CSIC28049Cantoblanco(Madrid)Spain

The magnetoimpedance effect and changes of the relaxation frequency fx are studied in CoFeSiB and CoFeMoSiB amorphous and FeCuNbSiB nanocrystalline ribbons. The evolution of the magnetostriction constant λs and relaxation frequency is analysed for the states with different magnetic anisotropies induced in the same ribbons. A monotonic decrease of the relaxation frequency is observed for shifting of λs towards positive values.

关键词： Nanocrystals

CONVERGENCE OF WEIGHTED AVERAGES OF MARTINGALES IN NONCOMMUTATIVE BANACH FUNCTION SPACES

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Acta Mathematica Scientia 2012年第2期32卷 735-744页

作者：张超侯友良 School of Mathematics and Statistics Wuhan University Departamento de Matema'ticas Facultad de CienciasUniversidad Autónoma de MadridMadrid 28049Spain

Let x （xn）≥1 be a martingale on a noncommutative probability space n （M, r） and （wn）n≥1 a sequence of positive numbers such that Wn = ∑ k=1^n wk →∞ as n →∞ We prove that x = （x.）n≥1 converges in E（M） if and only if （σn（x）n≥1 converges in E（.hd）, where E（A//） is a noncommutative rearrangement invariant Banach function space with the Fatou property and σn（x） is given by σn（x） = 1/Wn ∑k=1^n wkxk, n=1, 2, .If in addition, E（Ad） has absolutely continuous norm, then, （an（x））≥1 converges in E（.M） if and only if x = （Xn）n≥1 is uniformly integrable and its limit in measure topology x∞∈ E（M）.

关键词： Weighted average noncommutative martingales noncommutative BanachfunCtion spaces uniform integrability

Hölder,Sobolev,weak-type and BMO estimates in mixed-norm with weights for parabolic equations

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Science China Mathematics 2021年第1期64卷 129-154页

作者： Pablo Raúl Stinga José L.Torrea Department of Mathematics Iowa State UniversityAmesIA50011USA Departamento de Matemáticas Universidad Autónoma de MadridMadrid28049Spain

We prove weighted mixed-norm Lqt(W2,px)and Lqt(C2,αx)estimates for 10,x∈Rn.x∈Rn,The coefficients a(t)=(aij(t))are just bounded,measurable,symmetric and uniformly ***,we show strong,weak type and BMO-Sobolev estimates with parabolic Muckenhoupt *** is quite remarkable that most of our results are new even for the classical heat equation∂tu−Δu+u=f.

关键词： Calderón-Zygmund parabolic singular integrals weak type and BMO estimates representation formulas parabolic equations mixed-norm Sobolev and Schauder estimates