Search results for "RAV"
showing 10 items of 5866 documents
Backward transition radiation in the extreme ultraviolet region as a tool for the transverse beam profile diagnostic
2014
The present article summarizes the results of two experiments which were performed to study the radiation properties of backward transition radiation (BTR) in the extreme ultraviolet (EUV) region. This wavelength region is of particular interest for transverse beam profile imaging, because the spatial resolution is improved as a result of the reduced contribution in the imaging process of the fundamental diffraction limit. In addition, the influence of coherent effects in the transition radiation emission process, which have been observed in the visible region, might be mitigated. The first experiment, dedicated to the investigation of the BTR angular characteristics, indicates that the rad…
Selective guest inclusion of linear C6 hydrocarbons in a Zn(ii) 1D coordination polymer
2021
Trapping of volatile unbranched C6 hydrocarbons (hexane, 1-hexene, and 1-hexyne) in a 1D coordination polymer is reported. The guest inclusion was studied quantitatively by 1H-NMR analysis and thermogravimetric measurements, while synchrotron single-crystal diffraction data allowed advancing the view of their confinement into linear CP channels. Adsorption experiments performed through solid/vapour processes on microcrystals of CP 1 showed a certain degree of selectivity for 1-hexyne, which could be rationalized by its larger dipole moment.
Cation Distribution in a Titanium Ferrite Fe2.75Ti0.25O4Measured byin-SituAnomalous Powder Diffraction Using Rietveld Refinement
1998
Many ferrites contain different cations with various valence states and location in the spinel structure. In compounds such as these, only a combination of different techniques such as Mussbauer spectroscopy, IR analysis, and thermogravimetry allows the distribution of cations to be obtained. For very complicated distributions, the mathematical decomposition of derivative thermogravimetric curves (DTG) leading to quantitative distribution is uncertain. In this paper, we present an alternative technique based on resonant diffraction. The anomalous scattering of each cation in the crystalline material is used to determine its amount and position by Rietveld refinement. Since the energy for su…
Structure analysis of titanate nanorods by automated electron diffraction tomography
2011
A hitherto unknown phase of sodium titanate, NaTi3O6(OH)·2H2O, was identified as the intermediate species in the synthesis of TiO2 nanorods. This new phase, prepared as nanorods, was investigated by electron diffraction, X-ray powder diffraction, thermogravimetric analysis and high-resolution transmission electron microscopy. The structure was determined ab initio using electron diffraction data collected by the recently developed automated diffraction tomography technique. NaTi3O6(OH)·2H2O crystallizes in the monoclinic space group C2/m. Corrugated layers of corner- and edge-sharing distorted TiO6 octahedra are intercalated with Na+ and water of crystallization. The nanorods are typically …
Peracetylated β‐cyclodextrin as solubilizer of arylphosphines in supercritical carbon dioxide
2006
Abstract Effect of peracetylated β-cyclodextrin on the solubility of diphenyl(4-phenylphenyl)phosphine in supercritical carbon dioxide medium has been investigated. As shown by gravimetric measurements, the presence of cyclodextrin (CD) (1 equivalent) allows to increase the solubility of phosphine (P) in supercritical carbon dioxide (scCO 2 ) (40 °C, 35.2 MPa, nominal system density 0.89 g/mL). This solubility enhancement was attributed to host–guest interactions in scCO 2 as the P was recovered in the form of an inclusion complex. Furthermore, a diffuse reflectance spectroscopy study on the samples recovered after the experiments and on various CD/P solid mixtures obtained by co-grinding i…
The formation of peak rings in large impact craters.
2016
The Chicxulub impact crater, known for its link to the demise of the dinosaurs, also provides an opportunity to study rocks from a large impact structure. Large impact craters have “peak rings” that define a complex crater morphology. Morgan et al. looked at rocks from a drilling expedition through the peak rings of the Chicxulub impact crater (see the Perspective by Barton). The drill cores have features consistent with a model that postulates that a single over-heightened central peak collapsed into the multiple-peak-ring structure. The validity of this model has implications for far-ranging subjects, from how giant impacts alter the climate on Earth to the morphology of crater-dominated …
Nursing: more used medicines in the emergency rooms of hospitals
2007
El Servicio de Urgencias del C.H.G.U.V. cuenta con una plantilla de 84 Enfermeros/as. Una parte considerable de ellos es personal de nueva incorporación, de ahí que sea prioritaria la elaboración de protocolos de actuación. La administración de medicación intravenosa es sin duda una de las técnicas de mayor aplicación en los pacientes que acuden a Urgencias, que en nuestro Hospital oscila entre 550-600 atenciones diarias. Por ello nos planteamos, mediante la realización de reuniones de grupo, la elaboración del presente trabajo con el objetivo de elaborar un manual informativo sobre la medicación más habitual utilizada en nuestro Servicio de Urgencias; indicaciones, contraindicaciones, dilu…
Assessing flow resistance in gravel bed channels by dimensional analysis and self-similarity
2018
Abstract In this paper a new flow resistance equation for open channel flow, based on the integration of a power velocity profile, was tested for gravel bed channels. First this flow resistance equation, theoretically deduced by dimensional analysis and incomplete self-similarity condition, was reported. Then a relationship between the Γ function of the velocity profile, the channel slope and the Froude number was calibrated by the available laboratory measurements of flow velocity, water depth and bed slope carried out in 416 flume experimental runs with a gravel bed. Then the relationship for estimating Γ function and the theoretical resistance equation was tested by 83 independent flume …
Experimental study of boulder concentration effect on flow resistance in gravel bed channels
2021
Abstract Previous studies demonstrated that for open channel flows the power velocity profile can be integrated to obtain the flow resistance law. In this paper the relationship between Γ coefficient of the power velocity distribution, the channel slope and Froude number (Eq. (9) ) is firstly presented. Then the measurements carried out in a laboratory flume covered by hemispheric elements for two different hydraulic conditions (partially inundated and inundated) are used to calibrate this relationship. These elements are placed with a square arrangement and have a concentration range 4–64%. For the two investigated hydraulic conditions, this analysis demonstrates that the relationship to e…
Lo spettro impulsivo-compulsivo nell’addiction: una prospettiva in- tegrata sullo sviluppo delle dipendenze patologiche in adolescenza
2008
The evaluation of alcohol use disorder is the important first stage of interven- tions and treatments. The S.A.I.D. is an auto-evaluation test built on the assumption that alcoho- lism is close connected to the other person’s life problems that may have contributed to rouse, exacerbate or maintain alcoholism. The test is composed of 39 items, presented as auto-descriptions, that provide patient’s diagnostic profile articulated in two specific areas (social area and psycho- logical area), each divided in 9 scales (work/study; relationships; social relation- ship; cure/physical health; depression; hostility; inattention, anxiety,alexitimya) investigated through specific behavioural indexes th…