Search results for "Surfaces"
showing 10 items of 2837 documents
Atomic, electronic and thermodynamic properties of cubic and orthorhombic LaMnO3 surfaces
2009
We studied in detail the atomic and electronic structure of the LaMnO3 surfaces, in both cubic and orthorhombic phases, combining GGA-plane wave approach, as implemented into the VASP-4.6.19 computer code, with a slab model. These studies are complemented by a thermodynamic analysis of the surface stability at different gas pressures and temperatures. The obtained results are compared with similar studies for other ABO3-perovskites. 2008 Elsevier B.V. All rights reserved. The ABO3-type perovskite manganites and cobaltates (A = La, Sr, Ca; B = Mn, Co) are important functional materials with numerous high-tech applications [1]. Some of them require understanding and control surface properties…
Thermal and light induced polymorphism in iron(II) spin crossover compounds.
2004
The spin crossover complexes {Fe[H2B(pz)2]2L} ([H2B(pz)2]2 = dihydrobis(pyrazolyl)borate, L = 2,2'-bipyridine (1), bipy and 1,10-phenanthroline, phen (2)) undergo both thermal and light induced spin crossover, but the structure of the low spin and light induced high spin states for 2 are different from that of the thermally induced high spin state and from those of 1. Real Cabezos, Jose Antonio, Jose.A.Real@uv.es
Crystal structure determination of a new LaPO4 phase in a multicomponent glass ceramic via 3D electron diffraction
2022
Abstract A glass ceramic from the MgO–Al2O3–SiO2 system containing additives of ZrO2, TiO2, La2O3 and P2O5 was investigated. Via x-ray powder diffraction (XRPD) and Transmission electron microscopy(TEM) the crystalline phases present could be identified as MgAl2O4 (Spinel), orthorhombic ZrTiO4 and a polymorph of LaPO4 with a previously unknown crystal structure. The crystal structure of this LaPO4 phase was solved ab initio via 3D ED Data. The polymorph occurs in a distorted barite structure type in the same space group (P21/n) as the stable monazite type polymorph, however the density is higher and the La has a higher coordination number. Furthermore the LaPO4 is present in a spinodal reli…
Fabrication of Chemically Tunable, Hierarchically Branched Polymeric Nanostructures by Multi-branched Anodic Aluminum Oxide Templates
2016
In this paper, a template-assisted replication method is demonstrated for the fabrication of hierarchically branched polymeric nanostructures composed of post-modifiable poly(pentafluorophenyl acrylate). Anodic aluminum oxide templates with various shapes of hierarchically branched pores are fabricated by an asymmetric two-step anodization process. The hierarchical polymeric nanostructures are obtained by infiltration of pentafluorophenyl acrylate with a cross-linker and photoinitiator, followed by polymerization and selective removal of the template. Furthermore, the nanostructures containing reactive pentafluorophenyl ester are modified with spiropyran amine via post-polymerization modifi…
Yttria-stabilized zirconia in-flight particle characteristics under vacuum plasma spray conditions
2009
This paper deals with the diagnostic yttria-stabilized zirconia (YSZ) in-flight particles in Vacuum Plasma Spray (VPS) process using an optical measurement device. Particle velocity, temperature and diameter were correlated to spray distance under a fixed chamber pressure of about 14 kPa. Experiments were carried out with a two-color pyrometer. Results show that correlations can be satisfactory described with linear relationships. Particle velocity and temperature decrease when increasing spray distance whereas particle diameter exhibits a linear increase with the spray distance.
Digital background calibration algorithm and its FPGA implementation for timing mismatch correction of time-interleaved ADC
2019
Sample time error can degrade the performance of time-interleaved analog to digital converters (TIADCs). A fully digital background algorithm is presented in this paper to estimate and correct the timing mismatch errors between four interleaved channels, together with its hardware implementation. The proposed algorithm provides low computation burden and high performance. It is based on the simplified representation of the coefficients of the Lagrange interpolator. Simulation results show that it can suppress error tones in all of the Nyquist band. Results show that, for a four-channel TIADC with 10-bit resolution, the proposed algorithm improves the signal to noise and distortion ratio (SN…
Stable maps from surfaces to the plane with prescribed branching data
2007
Abstract We consider the problem of constructing stable maps from surfaces to the plane with branch set a given set of curves immersed (except possibly with cusps) in the plane. Various constructions are used (1) piecing together regions immersed in the plane (2) modifying an existing stable map by a sequence of codimension one transitions (swallowtails etc) or by surgeries. In (1) the way the regions are pieced together is described by a bipartite graph (an edge C* corresponds to a branch curve C with the vertices of C* corresponding to the two regions containing C). We show that any bipartite graph may be realized by a stable map and we consider the question of realizing graphs by fold ma…
Competitive Profiling of Ligandable Cysteines in Staphylococcus aureus with an Organogold Compound
2022
With the idea of exploiting metal-templated reactions to achieve selective modification of cysteines in proteins for antibacterial applications, an organometallic cyclometalated Au(III) compound was explored in a competitive chemoproteomic approach based on the isoDTB-ABPP (isotopically labelled desthiobiotin azide-activity-based protein profiling) technology in S. aureus cell extracts. In this way, more than 100 ligandable cysteines where identified, of which 10 were close to functional sites of proteins encoded by essential genes indicating potential for antibiotic development. Interestingly, more than 50% of the identified ligandable sites were not engaged by organic α-chloroacetamides i…
Effect of Cholesterol on Electrostatics in Lipid−Protein Films of a Pulmonary Surfactant
2010
We report the changes in the electrical properties of the lipid-protein film of pulmonary surfactant produced by excess cholesterol. Pulmonary surfactant (PS) is a complex lipid-protein mixture that forms a molecular film at the interface of the lung's epithelia. The defined molecular arrangement of the lipids and proteins of the surfactant film gives rise to the locally highly variable electrical surface potential of the interface, which becomes considerably altered in the presence of cholesterol. With frequency modulation Kelvin probe force microscopy (FM-KPFM) and force measurements, complemented by theoretical analysis, we showed that excess cholesterol significantly changes the electri…
A static SIMS study of superficial reactions (O2, (CN)2) on silver
1998
Abstract The exposure of silver surfaces to oxygen under about 10 −6 mbar at room temperature was studied mainly by secondary ion mass spectrometry (SIMS) used in a static mode. No reactivity of oxygen appeared under these exposure conditions in accordance with previous works. No modifications in the AES spectra, but an unexpected and huge increase in the intensities of secondary ions such as CN − , CNO − , Ag(CN) − 2 , Ag 2 CN + were observed. Different experiments were performed in order to specify the origin of this unexpected reaction in presence of pure oxygen. Moreover, exposures to pure (CN) 2 and to a mixture of cyanogen and oxygen were performed in order to compare the reactivity o…