Javier Méndez
A5001946969- Gamma-ray bursts and supernovae
- Molecular Junctions and Nanostructures
- Graphene research and applications
- Astrophysics and Cosmic Phenomena
- Surface Chemistry and Catalysis
- Surface and Thin Film Phenomena
- Astronomy and Astrophysical Research
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Stellar, planetary, and galactic studies
- Electronic and Structural Properties of Oxides
- Astro and Planetary Science
- Force Microscopy Techniques and Applications
- Electron and X-Ray Spectroscopy Techniques
- Advanced Chemical Physics Studies
- Copper-based nanomaterials and applications
- Fullerene Chemistry and Applications
- Semiconductor materials and devices
- ZnO doping and properties
- Diamond and Carbon-based Materials Research
- Catalytic Processes in Materials Science
- Quantum and electron transport phenomena
- Astronomical Observations and Instrumentation
- Advanced Materials Characterization Techniques
- Semiconductor Quantum Structures and Devices
Instituto de Ciencia de Materiales de Madrid
2015-2025
Instituto de Ciencia de Materiales de Sevilla
2014-2023
Consejo Superior de Investigaciones Científicas
2004-2020
Universidad Autónoma de Madrid
1992-2020
Isaac Newton Group
2007-2019
Science Factory
2017
Unidades Centrales Científico-Técnicas
2016
Universitat de Barcelona
2002-2014
Exelis (United States)
2012
University of Puerto Rico-Mayaguez
2008-2009
We report measurements of ΩM, ΩΛ, and w from 11 supernovae (SNe) at z = 0.36-0.86 with high-quality light curves measured using WFPC2 on the Hubble Space Telescope (HST). This is an independent set high-redshift SNe that confirms previous SN evidence for accelerating universe. The available photometry make it possible these alone to provide cosmological parameters comparable in statistical weight results. Combined earlier Supernova Cosmology Project data, new yield a measurement mass density...
We present a new compilation of Type Ia supernovae (SNe Ia), dataset low-redshift nearby-Hubble-flow SNe and analysis procedures to work with these heterogeneous compilations. This ``Union'' 414 SN Ia, which reduces 307 after selection cuts, includes the recent large samples from Supernova Legacy Survey ESSENCE Survey, older datasets, as well recently extended distant observed HST. A single, consistent blind procedure is used for all various subsamples, implemented that consistently weights...
This paper shows that the nanostructures deposited at room temperature in scanning tunneling microscopy experiments are produced by mechanical contact between tip and sample. Gold mounds gold substrates it is observed current flowing sample quantized resistance can be as low 100 \ensuremath{\Omega}.
We present an overview of the main techniques for production and processing graphene related materials (GRMs), as well key characterization procedures. adopt a 'hands-on' approach, providing practical details procedures derived from literature authors' experience, in order to enable reader reproduce results.
The Sloan Digital Sky Survey-II (SDSS-II) has embarked on a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z 0.35) Type Ia supernovae (SNe Ia) using repeated five-band (ugriz) imaging over an area of 300 sq. deg. survey region is stripe 2.5° wide centered the celestial equator in Southern Galactic Cap that been imaged numerous times earlier years, enabling construction deep reference image discovery new objects. Supernova observations are being...
Material structures of reduced dimensions exhibit electrical and mechanical properties different from those in the bulk. Measurements room-temperature electronic transport pulled metallic nanowires are presented, demonstrating that conductance characteristics depend on length, lateral dimensions, state degree disorder, elongation mechanism wire. Conductance during short wires (length ℓ ∼ 50 angstroms) exhibits periodic quantization steps with characteristic dips, correlating order-disorder...
We report hot filament thermal CVD (HFTCVD) as a new hybrid of and demonstrate its feasibility by producing high quality large area strictly monolayer graphene films on Cu substrates. Gradient in gas composition flow rate that arises due to smart placement the substrate inside Ta wound alumina tube accompanied radical formation precracking coupled with mediated physicochemical processes like diffusion, polymerization etc., led growth. further confirmed our mechanistic hypothesis depositing...
Aims.We present a study of the optical and near-infrared (NIR) properties Type Ia Supernova (SN Ia) 2003du.
We present comprehensive photometric and spectroscopic observations of the faint transient SN 2008S discovered in NGC 6946. exhibited slow evolution almost no spectral variability during first nine months, implying a high density CS medium. The light curve is similar shape to that 1998S 1979C, although significantly fainter at maximum light. Our quasi-bolometric lightcurve extends 300 days shows tail phase decay rate consistent with ^{56}Co. propose this evidence for an explosion formation...
There is a correlation between the corrosion resistance, structure, roughness and porosity of TaN sputtered films.
Evidence of high-velocity features (HVFs) such as those seen in the near-maximum spectra some Type Ia supernovae (SNe Ia; e.g., SN 2000cx) has been searched for available observed earlier than 1 week before B maximum. Recent observational efforts have doubled number SNe with very early spectra. Remarkably, all data (seven our Research Training Network sample and 10 from other programs) show signs features, to a greater or lesser degree, Ca II IR also Si λ6355 line. HVFs may be interpreted...
We present optical/near-infrared photometry and spectra of the type Ia SN 2002bo spanning epochs from -13 days before maximum B-band light to +102 after.The pre-maximum optical coverage is particularly complete.The extinction deduced observed colour evolution interstellar NaID absorption quite high viz.E(B -V ) = 0.43 ± 0.10.On other hand, model matches point a lower reddening (E(B ∼ 0.30).In some respects, behaves as typical "Branch normal" supernova (SN Ia) at IR wavelengths.We find...
Optical and near-infrared observations of the Type Ic supernova (SN) 2004aw are presented, obtained from day -3 to +413 with respect B-band maximum. The photometric evolution is characterised by a comparatively slow post-maximum decline light curves. peaks in redder bands significantly delayed relative bluer bands, I-band maximum occurring 8.4 days later than that B. With an absolute peak magnitude -18.02 V band SN can be considered fairly bright, but not exceptional. This also holds for U...
We present new results on the Hubble diagram of distant type Ia supernovae (SNe Ia) segregated according to host galaxy. This makes it possible check earlier evidence for a cosmological constant by explicitly comparing SNe residing in galaxies likely contain negligible dust with larger sample. The parameters derived from these hosted presumed dust-free early-type support claims constant, which we demonstrate at ≃5σ significance, and internal extinction implied is small even late-type systems...
We present an extensive new time-series of spectroscopic data the peculiar SN 1999aa in NGC 2595. Our set includes 25 optical spectra between -11 and +58 days with respect to B-band maximum light, providing unusually complete time history. The early resemble those a 1991T-like object but relatively strong Ca H&K absorption feature. first clear sign Si II 6355, characteristic Type Ia supernovae, is found at day -7 its velocity remains constant up least month after light. transition...
As part of the European Supernova Collaboration we obtained extensive photometry and spectroscopy type Ia SN 2002dj covering epochs from 11 days before to nearly two years after maximum. Detailed optical near-infrared observations show that this object belongs class high-velocity gradient events as indicated by Si, S Ca lines. The light curve shape velocity evolution appear be identical 2002bo. only significant difference is observed in near-IR colours a reduced spectral emission beyond 6500...
We have studied large areas of $(\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})R30\ifmmode^\circ\else\textdegree\fi{}$ graphene commensurate with a Pt(111) substrate. A combination experimental techniques ab initio density functional theory indicates that this structure is related to reconstruction at the Pt surface, consisting an ordered vacancy network formed in outermost layer and covalently bound The formation enhanced if low temperatures polycyclic aromatic hydrocarbons are used as...
We report the $\mathrm{Ni}\phantom{\rule{0.2em}{0ex}}2p$ x-ray photoelectron spectra of NiO thin films grown on different oxide substrates, namely, $\mathrm{Si}{\mathrm{O}}_{2}$, ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$, and MgO. The main line is attributed to bulk component, shoulder at $1.5\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ higher binding energies surface component. show strong differences with respect that NiO. energy separation between peak increases substrate covalence. This indicates...
Surface-assisted cyclodehydrogenation and dehydrogenative polymerization of polycyclic (hetero)aromatic hydrocarbons (PAH) are among the most important strategies for bottom-up assembly new nanostructures from their molecular building blocks. Although diverse compounds have been formed in recent years using this methodology, a limited knowledge on machinery operating at nanoscale has prevented rational control reaction outcome. We show that strength PAH-substrate interaction rules...