Scientific Papers in SCI

2012


Title: Software package to calculate the effects of the core hole and surface excitations on XPS and AES
Author(s): Tougaard, S; Yubero, F
Source: Surface and Interface Analysis, 44 (2012) 1114-1118

abstract | fulltext

We report on a new software package that allows to calculate the energy loss processes in a photo- and Auger electron spectrum. The calculations are performed within our previously published semiclassical dielectric response model. The model takes into account energy loss, which takes place because of the sudden creation of the static core hole and as the photoelectron travels in the bulk, passes the surface region and continues in the vacuum where it interacts with its image charge before it ends up in the electron spectrometer. It is a one-step model, which includes interference effects between these excitations. The only input in the calculations is the dielectric function of the material. We discuss the capabilities of the software and illustrate some examples of its practical application, including comparison with experimental spectra. We hope the software will be useful for the investigations of fundamental excitation mechanisms in XPS and AES. The software is free for noncommercial use.

August, 2012 | DOI: 10.1002/sia.4855

Title: Oxidative Dehydrogenation of Ethanol over Au/TiO2 Photocatalysts
Author(s): Sannino, Diana; Vaiano, Vincenzo; Ciambelli, Paolo; Carmen Hidalgo, M.; Murcia, Julie J.; Antonio Navio, J.
Source: Journal of Advanced Oxidation Technologies, 15 (2012) 284-293

abstract | fulltext

Au/TiO2 photocatalysts were used in ethanol oxidative dehydrogenation. Catalysts at gold loading ranging between 0.5-2 wt.% were synthesized by photodeposition (using different deposition times: 15 and 120 min) over an own-prepared TiO2 by sol-gel method. For reference purposes, a commercial 1 wt.% Au/TiO2 catalyst (AUROlite (TM), Strem Chemicals) was also tested. Photocatalytic reactions were carried out in a gas-solid photocatalytic fluidized bed reactor. Catalytic activity depends strongly both on Au loading and on the material properties, such as particle size and distribution of metal on titania surface. Acetaldehyde was the main reaction product, with ethylene, crotonaldehyde and CO2 as by-products. An important improvement of TiO2 photoactivity was achieved for the catalyst with 0.5 wt.% gold prepared with 120 min deposition time. For an ethanol inlet concentration of 0.2 vol% at 60 degrees C, the maximum conversion and acetaldehyde selectivity were 82% and 95%, respectively. These values are considerably higher than those obtained over pristine TiO2 and over the commercial catalyst.

July, 2012 | DOI: ---

Title: Thermal conductivity of high-porosity heavily doped biomorphic silicon carbide prepared from sapele wood biocarbon
Author(s): Parfen'eva, LS; Orlova, TS; Smirnov, BI; Smirnov, IA; Misiorek, H; Mucha, J; Jezowski, A; Cabezas-Rodriguez, R; Ramirez-Rico, J
Source: Physics of the Solid State, 54 (2012) 1732-1739

abstract | fulltext

The electrical resistivity and thermal conductivity of high-porosity (~52 vol %, channel-type pores) bio-SiC samples prepared from sapele wood biocarbon templates have been measured in the temperature range 5-300 K. An analysis has been made of the obtained results in comparison with the data for bio-SiC samples based on beech and eucalyptus, as well as for polycrystalline β-SiC. The conclusion has been drawn that the electrical resistivity and thermal conductivity of bio-SiC samples based on natural wood are typical of heavily doped polycrystalline β-SiC.

August, 2012 | DOI: 10.1134/S1063783412080240

Title: Electrical resistivity and thermal conductivity of SiC/Si ecoceramics prepared from sapele wood biocarbon
Author(s): Parfen'eva, LS; Orlova, TS; Smirnov, BI; Smirnov, IA; Misiorek, H; Mucha, J; Jezowski, A; Pardo, AG; Rico, JR
Source: Physics of the Solid State, 54 (2012) 2132-2141

abstract | fulltext

Samples of β-SiC/Si ecoceramics with a silicon concentration of ∼21 vol % have been prepared using a series of consecutive procedures (carbonization of sapele wood biocarbon, synthesis of high-porosity biocarbon with channel-type pores, infiltration of molten silicon into empty channels of the biocarbon, formation of β-SiC, and retention of residual silicon in channels of β-SiC). The electrical resistivity ρ and thermal conductivity κ of the β-SiC/Si ecoceramic samples have been measured in the temperature range 5–300 K. The values of ρ Si chan(T) and κ Si chan(T) have been determined for silicon Sichan located in β-SiC channels of the synthesized β-SiC/Si ecoceramics. Based on the performed analysis of the obtained results, the concentration of charge carriers (holes) in Sichan has been estimated as p ∼ 1019 cm−3. The factors that can be responsible for such a high value of p have been discussed. The prospects for practical application of β-SiC/Si ecoceramics have been considered.

October, 2012 | DOI: 10.1134/S1063783412100289

Title: Mechanochemical Synthesis and Characterization of II-VI Nanocrystals: Challenge for Cytotoxicity Issues
Author(s): Balaz, P; Jardin, R; Dutkova, E; Sayagues, MJ; Balaz, M; Mojzisova, G; Mojzis, J; Turianicova, E; Fabian, M
Source: Acta Physica Polonica A, 122 (2012) 224-229

abstract | fulltext

CdSe@ZnS nanocrystals have been prepared by a two-step solid state mechanochemical synthesis. CdSe prepared from elements in the first step is mixed with ZnS synthesized from zinc acetate and sodium sulfide in the second step. The crystallite size of the new type CdSe@ZnS nanocrystals determined by X-ray diffraction Rietveld refined method was 35 nra and 10 Jam for CdSe and ZnS, respectively. Energy dispersive/transmission electron microscopy/energy dispersive spectroscopy methods show good crystallinity of the nanoparticles and scanning electron microscopy elemental mapping illustrate consistent distribution of Cd, Se, Zn and S elements in the bulk of samples. UV-VIS spectra show an onset at 320 urn with calculated bandgap 3.85 eV. This absorption arises from the vibration modes of Zn-S bonds. The nanocrystals show the blue shift from the bandgap of bulk ZnS (3.66 eV). The synthesized CdSe@ZnS nanocrystals have been tested for dissolution, cytotoxicity and L-cysteine conjugation. The dissolution of Cd was less than 0.05 mu g mL(-1) (in comparison with 0.8 mu g mL(-1) which was evidenced for CdSe alone). The very low cytotoxic activity for selected cancer cell lines has been evidenced. CdSe@ZnS nanocrystals coated with L-cysteine are water-soluble and have a great potential in biomedical engineering as fluorescent labels.

July, 2012 | DOI: ---

Title: Degradation of Two Historic Buildings in Northern Spain by Formation of Oxalate and Sulphate-Based Compounds
Author(s): Duran, A; Robador, MD; Perez-Rodriguez, JL
Source: International Journal of Architectural Heritage, 6 (2012) 342-358

abstract | fulltext

This study focused on the degradation processes for two historic buildings, one in a rural and one in an urban environment. Samples collected from the Romanesque Church of Torme and from two areas of the Cathedral of Burgos were studied by using optical and electron microscopy, x-ray spectrometry, x-ray diffraction, Fourier transform infrared spectroscopy and thermal analysis (TG/DTA/DTG). As result of the action of microorganisms, weddellite and whewellite were found to have formed over the entire external walls of the Church of Torme, built with dolomitic rock. Gypsum, formed by the effects of atmospheric pollution, appeared on lime plasters applied as protective coatings on the external stones of Burgos' Cathedral. Also discussed in this study is the different composition of these plasters, based on the use of calcareous and siliceous aggregates.

January, 2012 | DOI: 10.1080/15583058.2010.551447

Title: Processing of Swnt-Reinforced Yttria Stabilized Zirconia by Spark Plasma Sintering and Microstructure Characterization
Author(s): S. de Bernardi-Martín, R. Poyato, Diego Gómez García, Arturo Domínguez-Rodríguez
Source: Journal of Nano Research, 18-19 (2012) 317-323

abstract | fulltext

Single wall carbon nanotube reinforced yttria stabilized zirconia ceramic materials have been obtained by means of spark plasma sintering technique. Single wall carbon nanotubes were treated in an acid solution before mixing with zirconia powders to obtain a uniform distribution of both powders. This method allows obtaining ceramic materials with a grain size between 200 nanometers and 1 micron and with a grain size distribution which depends on processing conditions. This new route opens a new perspective for new ceramic composites tailoring with enhanced mechanical properties as structural materials

July, 2012 | DOI: 10.4028/www.scientific.net/JNanoR.18-19.317

Title: Analysis of the restoration of an historical organ: The case study of the Cavaillé-Coll organ of La Merced Church in Burgos, Spain
Author(s): Justo-Estebaranz, A; Herrera, LK; Duran, A; Siguenza, B; de Haro, MCJ; Laguna, O; Justo, A
Source: Studies in Conservation, 57 (2012) 21-28

abstract | fulltext

The restoration of the Cavaille-Coll Romantic organ housed in La Merced Church of Burgos, Spain is described in this paper. The organ was affected by a fire that took place in the church. The effect of the fire on the pipes differed depending on their location within the instrument. A combination of analytical techniques (X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray analysis, particle-induced X-ray emission, metallography, and specific density) allowed the accurate determination of the microstructures and compositions of the alloys used to make the different pipes of the organ, some of which had a high tin content and others which had a high lead content. The most damaged pipes were replaced by reconstructed pipes made out of metallic sheets of the same composition as the originals, to ensure a historically accurate sound.

January, 2012 | DOI: 10.1179/2047058411Y.0000000001

Title: Non-isothermal microcalorimetric evaluations in quenched and in cold-rolled Cu-9Ni-5.5Sn alloys
Author(s): Donoso, E; Dianez, MJ; Criado, JM
Source: Revista de Metalurgia, 48 (2012) 67-75

abstract | fulltext

The thermal aging of both a quenched and a cold rolled homogeneous supersaturated Cu-9 % wt Ni-5.5 wt % Sn alloy has been studied from differential scanning calorimetry (DSC) and microhardness measurements. An increase of the hardness during the aging of the quenched sample, because of the precipitation of a γ' phase, takes place. On the contrary, no hardness increase was observed during the aging of the cold rolled sample. A theoretical analysis of the enthalpy determined from the first DSC exothermic peak suggests that a segregation of the solute towards the dislocations occurs during the aging of the cold rolled alloy. The values of the n Avrami-Erofeev coefficients estimated from the kinetic analysis supports the above interpretations.

January, 2012 | DOI: 10.3989/revmetalm.1136

Title: Biomimetic mineralization of calcium phosphate on a functionalized porous silicon carbide biomaterial
Author(s): Dey, A; van den Hoogen, CJ; Rosso, M; Lousberg, N; Hendrix, MMRM; Friedrich, H; Ramirez-Rico, J; Zuilhof, H; de With, G; Sommerdijk, NAJM
Source: ChemPlusChem, 77 (2012) 694-699

abstract | fulltext

Porous biomorphic silicon carbide (bioSiC) is a structurally realistic, high-strength, and biocompatible material which is promising for application in load-bearing implants. The deposition of an osteoconductive coating is essential for further improvement of its integration with the surrounding tissue. A new strategy towards biomimetic calcium phosphate coatings on bioSiC is described. X-ray photoelectron spectroscopy (XPS) analysis shows that using 10-undecenoic acid methyl ester a covalently bound monolayer can be synthesized on the surface of the bioSiC. After hydrolysis it exposes carboxylic acid groups that promote the selective nucleation and growth of a very well-defined crystalline layer of calcium phosphate. The resulting calcium phosphate coating is characterized by X-ray diffraction and electron microscopy techniques. Further, ion beam imaging is employed to quantify the mineral deposition meanwhile, three-dimensional dual-beam imaging (FIB/SEM) is used to visualize the bioSiC/mineral interface. The monolayer is show to actively induce the nucleation of a well-defined and highly crystalline mixed octacalcium phosphate/hydroxyapatite (OCP/HAP) coating on implantable bioSiC substrates with complex geometry. The mild biomimetic procedure, in principle, allows for the inclusion of bioactive compounds that aid in tissue regeneration. Moreover, the mixed OCP/HAP phase will have a higher solubility compared to HAP, which, in combination with its porous structure, is expected to render the coating more reabsorbable than standard HAP coatings.

August, 2012 | DOI: http://onlinelibrary.wiley.com/doi/10.1002/cplu.201200118/full

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