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Machine learning guided high-throughput search of non-oxide garnets

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npj Computational Materials 2023年第1期9卷 1717-1725页

作者： Jonathan Schmidt Hai-Chen Wang Georg Schmidt miguel A.L.Marques Institut für Physik Martin-Luther-Universität Halle-WittenbergD-06099 HalleGermany

Garnets have found important applications in modern technologies including magnetorestriction,spintronics,lithium batteries,*** overwhelming majority of experimentally known garnets are oxides,while explorations(experimental or theoretical)for the rest of the chemical space have been limited in scope.A key issue is that the garnet structure has a large primitive unit cell,requiring a substantial amount of computational *** perform a comprehensive search of the complete chemical space for new garnets,we combine recent progress in graph neural networks with high-throughput *** apply the machine learning model to identify the potentially(meta-)stable garnet systems before performing systematic density-functional calculations to validate the *** discover more than 600 ternary garnets with distances to the convex hull below 100 meV⋅atom−*** includes sulfide,nitride,and halide *** analyze their electronic structure and discuss the connection between the value of the electronic band gap and charge balance.

关键词： structure sulfide oxides

Li2SnO3 branched nano- and microstructures with intense and broadband white-light emission

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Nano Research 2019年第2期12卷 441-448页

作者： miguel Garcia-Tecedor Javier Bartolome David Maestre Achim Trampert Ana Cremades Dpt. Fisica de Materials Facultad de CC. Fisicas Universidad Complutense de Madrid Madrid 28040 Spain Paul-Drude-Institut fur Festkorperelektronik Hausvogteiplatz 5-7 Berlin 10117 Germany Institute of Advanced Materials (INAM) Universitat Jaume I Castello 12006 Spain Dpt. Fisica de Materiales Facultad de CC. Ftsicas Universidad Complutense de Madrid Madrid 28040 Spain

Exploiting the synergy between microstructure, morphology and dimensions by suitable nanomaterial engineeri ng, can effectively upgrade the physical properties and material performances. Li2SnO3 elongated nano- and microstructures in form of belts, wires, rods and branched structures have been fabricated by a vapor-solid method at temperatures ranging from 700 to 900℃ using metallic Sn and Li2CO3 as precursors. The achievement of these new morphologies can face challenging applications for Li2SnO3, not only in the field of energy storage, but also as building blocks in optoelectronic devices. The micro? and nanostructures grown at 700 and 800℃ correspond to monoclinic Li2SnO3, while at 900℃ complex Li2S nO/SnO2 core-shell microstructures are grow n, as con firmed by X-ray diffractio n and Rama n spectroscopy. Transmission electron microscopy reveals structural disorder related to stacking faults in some of the branched structures, which is associated with the prese nee of the low-temperature phase of L12S nO3. The luminescent resp onse of these structures is domi nated by in tense emissi ons at 2, 2.5 and 3 eV, almost completely covering the whole range of the visible light spectrum. As a result, white-light emission is obtained without the need of phosphors or complex quantum well heterostructures. Enhanced functionality in applications such as in light-emitting devices could be exploited based on the high luminescenee intensity observed in some of the analysed Li2SnO3 structures.

关键词： lithium oxides white light emitters nanostructures luminescenee

Microstructural and photocatalytic characterization of cement-paste sol-gel synthesized titanium dioxide

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Frontiers of Structural and Civil Engineering 2016年第2期10卷 189-197页

作者： Elena CERRO-PRADA miguel MANSO Vicente TORRES Jesfs SORIANO Civil Engineering Department Universidad Politecnica de Madrid Alfonso XII 3 Madrid 28014 Spain Applied Physics Department Universidad Aut6noma de Madrid Ciudad Universitaria de Cantoblanco Madrid 28049 Spain Laboratory of Materials CEDEX Ministerio de Fomento de Espana Alfonso XIL Madrid 28014 Spain

ABSTRACT A routte for the in paste synthesis of TiO2 loaded cement is described. TiO2 sols are blended with fresh cement paste as an alternative process to add photocatalytic functionality to cement. The modification of cement paste structure after the addition ofTiO2 sols is analyzed by XRD, SEM and TGA. As a particular microstructural feature, TiO2 containing calcium silicate hydrate （C-H-S） particles are identified as networking centers ofa C-S-H gel fiber matrix. The increase of the TiO2 sol concentration induces a decrease of pore size and an increase in the specific surface area in the cement composites. The photocatalytic activity of the TiO2/cement system is evaluated from the degradation of Methylene Blue （MB） under UV irradiation, monitored through the absorbance at 665 nm. The results show that, although TiO2 phases reveal no long range order structure, the cement paste exothermal treatment in presence of hydrate products and alkaline conditions leads to a photocatalytic composite. Such new cement matrix may be twofold advantageous since it additionally promotes the formation of C-S-H gel, main determinant of cement mechanical properties.

关键词： cement composites photocatalytic TiO2 sol-gel C-S-H gel microstructure

Engineering nanoparticles for targeting rheumatoid arthritis： Past, present, and future trends

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Nano Research 2018年第9期11卷 4489-4506页

作者： Isabel Matos Oliveira Cristiana Goncalves Rui Lufs Reis Joaquim miguel Oliveira B's Research Group - Biomatefials Biodegradables and Biomimetics Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine AvePark 4805-017 Barco Guimaraes Portugal ICVS/3B's-PTGovernment Associate Laboratory University of Minho Campus de Gualtar 4710-057 Braga Portugal The Discoveries Centre for Regenerative and Precision Medicine Headquarters at University of Minho Avepark 4805-017 Barco Guimaraes Portugal

Rheumatoid arthritis （RA） is a chronic inflammatory disease characterized by synovial joint inflammation and cartilage and bone tissue destruction. Although there exist some treatment strategies for RA, they are not completely safe and effective. Therefore, it is important to develop and test new drugs for RA that specifically target inflamed/swollen joints and simultaneously attenuate other possible damages to healthy tissues. Nanotechnology can be a good alternative to consider when envisioning predse medication for treating RA. Through the use of nanopartides, it is possible to increase bioavailability and bioactivity of therapeutics and enable selective targeting to damaged joints. Herein, recent studies using nanoparticles for the treatment of RA, namely with liposomes, polymeric nanoparticles, dendrimers, and metallic nanoparticles, have been reviewed. These therapeutic strategies have shown great promise in improving the treatment over that by traditional drugs. The results of these studies confirm that feasibility of the use of nanopartides is mainly due to their biocompatibility, low toxicity, controlled release, and selective drug delivery to inflamed tissues in animal RA models. Therefore, it is possible to claim that nanotechnology will, in the near future, play a crucial role in advanced treatments and patient-specific therapies for human diseases such as RA.

关键词： nanoparticles liposomes dendrimers rheumatoid arthritis

Hybrid magnetorheological elastomers enable versatile soft actuators

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npj Computational Materials 2022年第1期8卷 1546-1559页

作者： miguel Angel Moreno-Mateos Mokarram Hossain Paul Steinmann Daniel Garcia-Gonzalez Department of Continuum Mechanics and Structural Analysis Universidad Carlos III de MadridAvda.de la Universidad 3028911LeganésMadridSpain Zienkiewicz Centre for Computational Engineering Faculty of Science and EngineeringSwansea UniversitySA18ENSwanseaUK Institute of Applied Mechanics University of Erlangen-NurembergEgerland Str.5ErlangenGermany Glasgow Computational Engineering Centre School of EngineeringUniversity of GlasgowG128QQGlasgowUK

Recent advances in magnetorheological elastomers(MREs)have posed the question on whether the combination of both soft-and hard-magnetic particles may open new routes to design versatile multifunctional ***,we conceptualise ultra-soft hybrid MREs(≈1–10 kPa stiffness)combining experimental and computational ***,a comprehensive experimental characterisation is *** results unravel that the magneto-mechanical performance of hybrid MREs can be optimised by selecting an adequate mixing ratio between ***,a multi-physics computational framework provides insights into the synergistic magneto-mechanical interactions at the *** particles amplify the magnetisation and hard particles contribute to torsional *** numerical results suggest that the effective response of hybrid MREs emerges from these intricate ***,we uncover exciting possibilities to push the frontiers of MRE *** are demonstrated by simulating a bimorph beam that provides actuation flexibility either enhancing mechanical bending or material stiffening,depending on the magnetic stimulation.

关键词： versatile magneto enable

Engineering operando methodology： Understanding catalysis in time and space

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Frontiers of Chemical Science and Engineering 2018年第3期12卷 509-536页

作者： Raquel Portela Susana Perez-Ferreras Ana Serrano-Lotina miguel A. Banares Instituto de Catalisis y Petroleoquimica ICP-CSIC Marie Curie 2 Madrid Spain

The term operando was coined at the begin- ning of this century to gather the growing efforts devoted to establish structure-activity relationships by simulta- neously characterizing a catalyst performance and the relevant surface chemistry during genuine catalytic opera- tion. This approach is now widespread and consolidated; it has become an increasingly complex but efficient junction where spectroscopy, materials science, catalysis and engineering meet. While for some characterization techni- ques kinetically relevant reactor cells with good resolution are recently developing, the knowledge gained with magnetic resonance and X-ray and vibrational spectro- scopy studies is already huge and the scope of operando methodology with these techniques is recently expanding from studies with small amounts of powdered solids to more industrially relevant catalytic systems. Engineering catalysis implies larger physical domains, and thus all sort of gradients. Space- and time- resolved multi-technique characterization of both the solid and fluid phases involved in heterogeneous catalytic reactions （including temperature data） is key to map processes from different perspectives, which allows taking into account existing heterogeneities at different scales and facing up- and down-scaling for applications ranging from microstructured reactors to industrial-like macroreactors （operating with shaped catalytic bodies and/or in integral regime）. This work reviews how operando methodology is evolving toward engineered reaction systems.

关键词： operando structured catalysts spaceresolved time-resolved spectroscopy

Looking at sound: optoacoustics with all-optical ultrasound detection

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Light(Science & Applications) 2018年第1期7卷 556-571页

作者： Georg Wissmeyer miguel A.Pleitez Amir Rosenthal Vasilis Ntziachristos Institute of Biological and Medical Imaging Helmholtz Zentrum MunchenNeuherbergGermany Chair of Biological Imaging Technische Universitat MunchenMunichGermany Andrew and Erna Viterbi Faculty of Electrical Engineering Technion-Israel Institute of TechnologyHaifaIsrael

Originally developed for diagnostic ultrasound imaging,piezoelectric transducers are the most widespread technology employed in optoacoustic(photoacoustic)signal ***,the detection requirements of optoacoustic sensing and imaging differ from those of conventional ultrasonography and lead to specifications not sufficiently addressed by piezoelectric ***,interest has shifted to utilizing entirely optical methods for measuring optoacoustic ***-optical sound detectors yield a higher signal-to-noise ratio per unit area than piezoelectric detectors and feature wide detection bandwidths that may be more appropriate for optoacoustic applications,enabling several biomedical or industrial ***,optical sensing of sound is less sensitive to electromagnetic noise,making it appropriate for a greater spectrum of *** this review,we categorize different methods of optical ultrasound detection and discuss key technology trends geared towards the development of all-optical optoacoustic *** also review application areas that are enabled by all-optical sound detectors,including interventional imaging,non-contact measurements,magnetoacoustics,and nondestructive testing.

关键词： sound acoustics piezoelectric

Factor analysis of correlation matrices when the number of random variables exceeds the sample size

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Statistical Theory and Related Fields 2017年第2期1卷 246-256页

作者： miguel Marino Yi Li Department of Family Medicine Oregon Health&Science UniversityPortlandORUSA Department of Biostatistics University of MichiganAnn ArborMIUSA

Factor analysis which studies correlation matrices is an effective means of data reduction whoseinference on the correlation matrix typically requires the number of random variables, p, to berelatively small and the sample size, n, to be approaching infinity. In contemporary data collection for biomedical studies, disease surveillance and genetics, p > n limits the use of existingfactor analysis methods to study the correlation matrix. The motivation for the research herecomes from studying the correlation matrix of log annual cancer mortality rate change for p = 59cancer types from 1969 to 2008 (n = 39) in the U.S.A. We formalise a test statistic to perform inference on the structure of the correlation matrix when p > n. We develop an approach based ongroup sequential theory to estimate the number of relevant factors to be extracted. To facilitateinterpretation of the extracted factors, we propose a BIC (Bayesian Information Criterion)-typecriterion to produce a sparse factor loading representation. The proposed methodology outperforms competing ad hoc methodologies in simulation analyses, and identifies three significant underlying factors responsible for the observed correlation between cancer mortality ratechanges.

关键词： Alpha spending function BIC cancer surveillance eigenvalues sparse factor loadings

Nonlinear numerical assessment of the seismic response of hillside RC buildings

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Earthquake Engineering and Engineering Vibration 2021年第2期20卷 423-440页

作者： miguel A.Gómez Edgar Giovanny Díaz-Segura Juan Carlos Vielma Civil Engineering School Pontificia Universidad Católica de ValparaísoValparaíso 2340000Chile

Major damage has been reported in hilly areas after major earthquakes,primarily because of two special conditions:the variation in the seismic ground motion due to the inclined ground surface and the irregularities caused by a stepped base level in the *** aim of this study is to evaluate possible differences in the responses of Chilean hillside buildings through numerical linear-elastic and nonlinear *** the first step,a set of response-spectrum analyses were performed on four simplified 2D structures with mean base inclination angles of 0°,15°,30°,and 45°.The structures were designed to comply with Chilean seismic codes and standards,and the primary response parameters were *** assess the seismic performance of the buildings,nonlinear static(pushover)and dynamic(time-history)analyses were performed with SeismoStruct *** analyses were used to compare the nonlinear response at the maximum roof displacement and the damage ***-history analyses were performed to assess the nonlinear dynamic response of the structures subjected to seismic ground motions modified by topographic *** consider the topographic modification,acceleration records were obtained from numerical models of soil,which were calculated using the rock acceleration record of the Mw 8.01985 Chilean *** differences in the structure responses(roof displacements and maximum element forces and moments)were caused by the topographic effects in the seismic input motion,with the highly predominant ones being the differences caused by the step-back configuration at the base of the *** concentrations of shear forces in short walls were observed,corresponding to the walls located in the upper zone of the foundation *** response of the structures with higher angles was observed to be more prone to fragile failures due to the accumulation of shear *** though hillside buildings gain stiffness in the lower stories,resulting

关键词： topographic effect hillside buildings nonlinear analyses shear-wall buildings