Search results for "face"

Fast proton conduction in hydrogen bonded microheterogeneous systems: Bis(2-ethylhexyl)phosphoric acid/N-methyl formamide liquid mixtures

2009

Structural and dynamical properties of bis(2-ethylhexyl)phosphoric acid (HDEHP)/N-methyl formamide (NMF) liquid mixtures in the whole composition range have been investigated by Fourier Transform Infrared spectroscopy (FT-IR), X-rays Diffraction (XRD), and AC complex impedance spectroscopy. Driven by hydrogen bond interactions among HDEHP PO(4)H group and NMF CO and NH groups, and also by steric effects among the HDEHP alkyl chains, the system microstructure is mainly characterized by the coexistence of spatially separated hydrophilic and hydrophobic nanodomains showing local organization and short-range order. The evolution of this structural feature with system composition has been highli…

Occurrence of acidic pharmaceuticals and personal care products in Turia River Basin: From waste to drinking water

2014

The occurrence of 21 acidic pharmaceuticals, including illicit drugs, and personal care products (PPCPs) in waste, surface and drinking water and in sediments of the Turia River Basin (Valencia, Spain) was studied. A liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for the determination of these PPCPs with electrospray (ESI) in negative ionization (NI) mode. Ammonium fluoride in the mobile phase improved ionization efficiency by an average increase in peak area of 5 compared to ammonium formate or formic acid. All studied compounds were detected and their concentration was waste water>surface water>drinking water. PPCPs were in waste water treatment plants (WWT…

Unveiling the environment and faint features of the isolated galaxy CIG 96 with deep optical and HI observations

2018

Context. Asymmetries in atomic hydrogen (HI) in galaxies are often caused by the interaction with close companions, making isolated galaxies an ideal framework to study secular evolution. The AMIGA project has demonstrated that isolated galaxies show the lowest level of asymmetry in their HI integrated profiles compared to even field galaxies, yet some present significant asymmetries. CIG 96 (NGC 864) is a representative case reaching a 16% level. Aims. Our aim is to investigate the HI asymmetries of the spiral galaxy CIG 96 and what processes have triggered the star-forming regions observed in the XUV pseudo-ring. Methods. We performed deep optical observations at CAHA1.23m, CAHA2.2m and V…

Conversational Gatekeeping : Social Interactional Practices of Post-Publication Gatekeeping on Newspapers’ Facebook Pages

2022

Digital platforms, such as social media networks, have become intertwined in the news ecosystem, leading news media to lose their role as the sole gatekeeper in the public space. This development has given an active voice to audiences and turned journalism more into conversations between journalists and their audiences. The starting observation for this article was that alongside journalists, platforms and audiences play a part in the gatekeeping process that takes place post-publication, and therefore we need to gain a better understanding of this triadic relationship. Furthermore, as conversations are one of the main functions of social media platforms, more understanding of the role of s…

The development of modern vacuum technique: Present position and tendencies

1963

MOCVD growth of CdO very thin films: Problems and ways of solution

2016

Abstract In this paper the growth of CdO by the MOCVD technique at atmospheric pressure has been studied in order to achieve very thin films of this material on r-sapphire substrates. The growth evolution of these films was discussed and the existence of a threshold thickness, below which island-shaped structures appear, was demonstrated. Some alternatives to reduce this threshold thickness have been proposed in the frame of the analysis of the crystal growth process. The morphology and structural properties of the films were analyzed by means of SEM and HRXRD. High-quality flat CdO samples were achieved with thicknesses up to 20 nm, which is five times thinner than the values previously re…

The Interplay Between Gesture and Discourse as Mediating Devices in Collaborative Mathematical Reasoning:A Multimodal Approach

2008

This article aims to identify the mathematical reasoning strategies expressed through gestures and speech used by two groups of sixth-grade pupils when solving a task related to the transition between two semiotic representations: figure and Cartesian diagram. The article also identifies the difficulties the pupils meet in the solution process. The analyses of the group dialogues focus particularly on the gesture dimension of deixis. The pupils in both groups have used the following deictic gestures: pointing, held-point, linear point-slide, and circular point-slide in their solution process, while repeated pointing has been identified only in one of the groups. These pointing gestures are …

Surface hysteresis curves of Fe(110) and Fe(100) crystals in ultrahigh vacuum — evidence of adsorbate influences

1992

Abstract We have investigated hysteresis curves of silicon-stabilized Fe(100) and Fe(110) crystals using Polarized Secondary Electron Emission (PSEE) for surface magnetization processes and Magneto-Optical Kerr Effect (MOKE) for bulk hysteresis curves. In particular, the influence of adsorbates (oxygen and sulphur) and surface roughness on the magnetization reversal has been studied. For surface hysteresis curves we found adsorbate-induced reductions of coercive force of up to 50%; the bulk hysteresis curves showed significantly smaller deviations. Similar changes were caused by surface disorder on an atomic scale induced by ion bombardment. The results agree qualitatively with a previous e…

Interligand Electron Transfer Determines Triplet Excited State Electron Injection in RuN3−Sensitized TiO2 Films

2004

Electron injection from the transition metal complex Ru(dcbpy)(2)(NCS)(2) (dcbpy = 2,2'-bipyridine-4,4'-dicarboxylate) into a titanium dioxide nanoparticle film occurs along two pathways. The dominating part of the electron injection proceeds from the initially excited singlet state of the sensitizer into the conduction band of the semiconductor on the sub-hundred-femtosecond time scale. The slower part of the injection occurs from the thermalized triplet excited state on the picosecond time scale in a nonexponential fashion, as was shown in a previous study (Benko, G.; et al. J. Am. Chem. Soc. 2002, 124, 489). Here we show that the slower channel of injection is the result of the excited s…

Engineering half-Heusler thermoelectric materials using Zintl chemistry

2016

In this Review, the structure, bonding and defects of half-Heusler compounds are explained in terms of the framework of Zintl (or valence-precise) chemistry. This deeper understanding of the structure and electronic properties of half-Heusler compounds should aid the design of improved thermoelectric materials.