1,974 research outputs found

    The local electronic structure of alpha-Li3N

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    New theoretical and experimental investigation of the occupied and unoccupied local electronic density of states (DOS) are reported for alpha-Li3N. Band structure and density functional theory calculations confirm the absence of covalent bonding character. However, real-space full-multiple-scattering (RSFMS) calculations of the occupied local DOS finds less extreme nominal valences than have previously been proposed. Nonresonant inelastic x-ray scattering (NRIXS), RSFMS calculations, and calculations based on the Bethe-Salpeter equation are used to characterize the unoccupied electronic final states local to both the Li and N sites. There is good agreement between experiment and theory. Throughout the Li 1s near-edge region, both experiment and theory find strong similarities in the s- and p-type components of the unoccupied local final density of states projected onto an orbital angular momentum basis (l-DOS). An unexpected, significant correspondence exists between the near-edge spectra for the Li 1s and N 1s initial states. We argue that both spectra are sampling essentially the same final density of states due to the combination of long core-hole lifetimes, long photoelectron lifetimes, and the fact that orbital angular momentum is the same for all relevant initial states. Such considerations may be generically applicable for low atomic number compounds.Comment: 34 pages, 7 figures, 1 tabl

    ‘Everyone should do it’: Client experience of a 12-week dialectical behaviour therapy group programme – An interpretative phenomenological analysis

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    Objective: There is a dearth of practice-based evidence of adapted or ‘DBTinformed’ transdiagnostic models, which could provide services and clinicians with information of what works and for whom, in which settings. This paper aims to bridge this gap by exploring the client experience of a 12-week transdiagnostic dialectical behaviour therapy (DBT) group programme in a private psychiatric hospital. Method: Five participants with varied clinical diagnoses and previous therapeutic experiences were interviewed following completion of one or more of the same adapted DBT programme, comprising of the standard four modules over 12 weeks, including a weekly skills group and 1:1 therapy. Interpretative phenomenological analysis (IPA) was applied to give voice to the clients’ lived experience of the group. Results: Three master themes were identified: ‘Pre DBT: Crisis & Desperation’; ‘In-session: Belonging’; and ‘The Real World: Living’, each characterised by four sub-themes, highlighting helpful and hindering factors of clients’ current and previous therapeutic experiences. Conclusion: Overall this version of DBT in a transdiagnostic setting was experienced as helpful and positive by participants; main outcomes included being able to build a life worth living, feel hope and joy, build DBT skills into a lifestyle, and develop reflective practice. Implications for clinical practice, service delivery and policy are also discussed. The article aims to provide clinicians with practice-based evidence to inform the delivery of DBT as well as supporting the case for the use of DBT with various disorders, thus paving the way for future research in this area

    Bench-scale synthesis of nanoscale materials

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    A novel flow-through hydrothermal method used to synthesize nanoscale powders is introduced by Pacific Northwest Laboratory. The process, Rapid Thermal Decomposition of precursors in Solution (RTDS), uniquely combines high-pressure and high-temperature conditions to rapidly form nanoscale particles. The RTDS process was initially demonstrated on a laboratory scale and was subsequently scaled up to accommodate production rates attractive to industry. The process is able to produce a wide variety of metal oxides and oxyhydroxides. The powders are characterized by scanning and transmission electron microscopic methods, surface-area measurements, and x-ray diffraction. Typical crystallite sizes are less than 20 nanometers, with BET surface areas ranging from 100 to 400 sq m/g. A description of the RTDS process is presented along with powder characterization results. In addition, data on the sintering of nanoscale ZrO2 produced by RTDS are included

    Little groups of irreps of O(3), SO(3), and the infinite axial subgroups

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    Little groups are enumerated for the irreps and their components in any basis of O(3) and SO(3) up to rank 9, and for all irreps of C∞_{\infty}, C∞h_{\infty h}, C∞v_{\infty v}, D∞_{\infty} and D∞h_{\infty h}. The results are obtained by a new chain criterion, which distinguishes massive (rotationally inequivalent) irrep basis functions and allows for multiple branching paths, and are verified by inspection. These results are relevant to the determination of the symmetry of a material from its linear and nonlinear optical properties and to the choices of order parameters for symmetry breaking in liquid crystals.Comment: 28 pages and 3 figure

    Early stages of ramified growth in quasi-two-dimensional electrochemical deposition

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    I have measured the early stages of the growth of branched metal aggregates formed by electrochemical deposition in very thin layers. The growth rate of spatial Fourier modes is described qualitatively by the results of a linear stability analysis [D.P. Barkey, R.H. Muller, and C.W. Tobias, J. Electrochem. Soc. {\bf 136}, 2207 (1989)]. The maximum growth rate is proportional to (I/c)δ(I/c)^\delta where II is the current through the electrochemical cell, cc the electrolyte concentration, and δ=1.37±0.08\delta = 1.37 \pm 0.08. Differences between my results and the theoretical predictions suggest that electroconvection in the electrolyte has a large influence on the instability leading to ramified growth.Comment: REVTeX, four ps figure

    Chasing Clarity: Rumination as a Strategy for Making Sense of Emotions

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    Research is needed on the affective mechanisms that motivate people to ruminate. One possibility is that some people might ruminate in response to deficits in emotional clarity because not knowing how they feel might be intolerable to them. We tested the hypothesis that the relationship between low emotional clarity and rumination would be moderated by intolerance of ambiguity. Participants in a longitudinal online study (N = 195) provided self- reports of intolerance of ambiguity and rumination and reported state emotional clarity following an idiographic mood induction; three weeks later they reported on rumination again. As predicted, participants with low emotional clarity at Time 1 ruminated more three weeks later, but only if they were intolerant of ambiguity. Findings support the notion that rumination sometimes functions as a search for answers about emotions. We discuss implications for understanding the affective disturbances perpetuating vicious cycles of rumination and for rumination-focused clinical interventions

    Experimental investigation of the initial regime in fingering electrodeposition: dispersion relation and velocity measurements

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    Recently a fingering morphology, resembling the hydrodynamic Saffman-Taylor instability, was identified in the quasi-two-dimensional electrodeposition of copper. We present here measurements of the dispersion relation of the growing front. The instability is accompanied by gravity-driven convection rolls at the electrodes, which are examined using particle image velocimetry. While at the anode the theory presented by Chazalviel et al. describes the convection roll, the flow field at the cathode is more complicated because of the growing deposit. In particular, the analysis of the orientation of the velocity vectors reveals some lag of the development of the convection roll compared to the finger envelope.Comment: 11 pages, 15 figures, REVTEX 4; reference adde
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