963 resultados para Time study


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Quantum-chemistry methods were explored to investigate the electronic structures, injection and transport properties, absorption and phosphorescence mechanism of a series of blue-emitting Ir(III) complexes {[(F-2-ppy)(2)Ir(pta -X/pyN4)], where F-2-ppy = (2,4-difluoro)phenylpyridine; pta = pyridine-1,2,4-triazole; X = phenyl(1); p-tolyl (2); 2,6-difluororophenyl (3); -CF3 (4), and pyN4 = pyridine-1,2,4-tetrazolate (5)}, which are used as emitters in organic light-emitting diodes (OLEDs). The mobility of hole and electron were studied computationally based on the Marcus theory. Calculations of Ionization potentials (IPs) and electron affinities (EAs) were used to evaluate the injection abilities of holes and electrons into these complexes.

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The complexation of acenaphthene and fluoranthene with beta-cyclodextrin (CD) in aqueous solutions in the presence and absence of ethanol was investigated by means of the time-resolved fluorescence technique. The appearance of a longer lifetime component and the increase of its fraction relative to that of the shorter lifetime component with increasing CD concentration demonstrate the formation of inclusion complex between the guest molecule and CD. The formation constants for complexation were derived from the pre-exponential factor A(i) of fluorescence decay curves. The presence of ethanol in the reaction systems enhanced the inclusion to a large extent.

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In this article, we describe an apparatus in our laboratory for investigating elementary chemical reactions using the high resolution time-of-flight Rydberg tagging method. In this apparatus, we have adopted a rotating source design so that collision energy can be changed for crossed beam studies of chemical reactions. Preliminary results on the HI photodissociation and the F atom reaction with H-2 are reported here. These results suggest that the experimental apparatus is potentially a powerful tool for investigating state-to-state dynamics of elementary chemical reactions. (c) 2005 American Institute of Physics.

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Submitted to Appl Magn Reson Sponsorship: EPSRC / EU

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Real-time adaptive music is now well-established as a popular medium, largely through its use in video game soundtracks. Commercial packages, such as fmod, make freely available the underlying technical methods for use in educational contexts, making adaptive music technologies accessible to students. Writing adaptive music, however, presents a significant learning challenge, not least because it requires a different mode of thought, and tutor and learner may have few mutual points of connection in discovering and understanding the musical drivers, relationships and structures in these works. This article discusses the creation of ‘BitBox!’, a gestural music interface designed to deconstruct and explain the component elements of adaptive composition through interactive play. The interface was displayed at the Dare Protoplay games exposition in Dundee in August 2014. The initial proof-of- concept study proved successful, suggesting possible refinements in design and a broader range of applications.

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Aim: This thesis examines a question posed by founding occupational scientist Dr. Elizabeth Yerxa (1993) – “what is the relationship between human engagement in a daily round of activity (such as work, play, rest and sleep) and the quality of life people experience including their healthfulness” (p. 3). Specifically, I consider Yerxa’s question in relation to the quotidian activities and health-related quality of life (HRQoL) of late adolescents (aged 15 - 19 years) in Ireland. This research enquiry was informed by an occupational perspective of health and by population health, ecological, and positive youth development perspectives. Methods: This thesis is comprised of five studies. Two scoping literature reviews informed the direction of three empirical studies. In the latter, cross-sectional time use and HRQoL data were collected from a representative sample of 731 school-going late adolescents (response rate 52%) across 28 schools across Cork city and county (response rate 76%). In addition to socio-demographic data, time use data were collected using a standard time diary instrument while a nationally and internationally validated instrument, the KIDSCREEN-52, was used to measure HRQoL. Variable-centred and person-centred analyses were used. Results: The scoping reviews identified the lack of research on well populations or an adolescent age range within occupational therapy and occupational science; limited research testing the popular assumption that time use is related to overall well-being and quality of life; and the absence of studies that examined adolescent 24-hour time use and quality of life. Established international trends were mirrored in the findings of the examination of weekday and weekend time use. Aggregate-level, variable-centred analyses yielded some significant associations between HRQoL and individual activities, independent of school year, school location, family context, social class, nationality or diary day. The person-centred analysis of overall time use identified three male profiles (productive, high leisure and all-rounder) and two female profiles (higher study/lower leisure and moderate study/higher leisure). There was tentative support for the association between higher HRQoL and more balanced time use profiles. Conclusion: The findings of this thesis highlight the gendered nature of adolescent time use and HRQoL. Participation in daily activities, singly and in combination, appears to be associated with HRQoL. However, the nature of this relationship is complex. Individually and collectively, adolescents need to be educated and supported to create health through their everyday patterns of doing.

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This paper studies a two-level supply chain consisting of components supplier and product assembly manufacturer, while the manufacturer shares the investment on shortening supply lead time. The objective of this research is to investigate the benefits of cost sharing strategy and adopting component commonality. The result of numerical analysis demonstrates that using component commonality can help reduce the total cost, especially when the manufacture shares a higher fraction of the cost of investment in shortening supply lead time.