Fabrication Of Smooth Diamond Films On Sio2 By The Addition Of Nitrogen To The Gas Feed In Hot-filament Chemical Vapor Deposition

The morphology of small roughness diamond films deposited onto thermally oxidized silicon substrates by a process of anisotropic crystalline growth induced by nitrogen in a hot-filament chemical vapor deposition (CVD) reactor was investigated. Square plates of low roughness were obtained on the top surface of the diamond films. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and micro-Raman spectroscopy indicated films made up of good quality. The films possessed a large number of defects due to substitutional nitrogen. Planar defects were created due to large amount of nitrogen introduced in the CVD process. Substitutional nitrogen provoked lateral vacancies that have a catalytic effect on the lateral rate of diamond growth.19410521056Angus, J.C., Hayman, C.C., (1988) Science, 241, p. 913Yarborough, W.A., Messier, R., (1990) Science, 241, p. 688Derjaguin, B.V., Fedoseev, D., (1977) Izd., , Nauka, Moscow, Chap. 4Tankala, K., DebRoy, T., (1992) J. Appl. Phys., 72, p. 712Okano, K., Koizumi, S., Silva, S.R.P., Amaratunga, G.A.J., (1996) Nature (London), 381, p. 140Liao, X.Z., Zhang, R.J., Lee, C.S., Tong Lee, S., Lam, Y.W., (1997) Diamond Relat. Mater., 6, p. 521Dos Santos Filho, S.G., Hasenack, C.M., Lopes, M.C.V., Baranauskas, V., (1995) Semicond. Sci. Technol., 10, p. 990Jin, S., Moustakas, T.D., (1994) Appl. Phys. Lett., 65, p. 403Locher, R., Wild, C., Herres, N., Behr, D., Koidl, P., (1996) Appl. Phys. Lett., 65, p. 759Walker, J.E., (1979) Rep. Prog. Phys., 42, p. 42Evans, T., Rainey, P., (1975) Proc. R. Soc. London, Ser. A, 344, p. 111Baranauskas, V., Li, B.B., Peterlevitz, A., Tosin, M.C., Durrant, S.F., (1999) J. Appl. Phys., 85, p. 7455Baranauskas, V., Peled, A., Trava-Airoldi, V.J., Lima, C.A.S., Doi, I., Corat, E.J., (1994) Appl. Surf. Sci., 79-80, p. 129Barros, R.C.M., Corat, E.J., Ferreira, N.G., Souza, T.M., Trava-Airoldi, V.J., Leite, N.F., Iha, K., (1996) Diamond Relat. Mater., 5, p. 1323Lang, A.R., (1964) Proc. Phys. Soc., 84, p. 871Sumida, N., Lang, A.R., (1988) Proc. R. Soc. London, Ser. A, 419, p. 235Bridon, P.R., Jones, R., (1993) Physica B, 185, p. 17

Post-mortem information management: exploring contextual factors in appropriate personal data access after death

\ua9 2024 The Author(s). Published with license by Taylor & Francis Group, LLC.With the increasing size and complexity of personal information and data landscapes, there is a need for guidance and support in the appropriate management of a deceased person’s postmortem privacy and digital legacy. However, most people engage poorly with existing mechanisms for specifying and planning for access and suitable usage of their own data. We report on two studies exploring the ways in which contextual factors such as the accessor and the data type may affect the appropriateness of personal data flows differently during life and after death. Our findings indicate that suitable data access after death is highly individual and contextual, with differences in appropriateness between during-life and after-death data flows significantly affected by the accessor and the data type in question. We identify that ambiguous accessor motivation, failure to communicate intent, changing temporal context and latent data values further complicate the act of digital legacy planning. Our findings also provide further evidence for the existence of a postmortem privacy paradox in which reported user behaviors do not reflect intent. With this in mind, we offer design recommendations for the integration of digital legacy planning functionality within Personal Information Management (PIM) and Group Information Management (GIM) systems

Prospects for photon blockade in four level systems in the N configuration with more than one atom

We show that for appropriate choices of parameters it is possible to achieve photon blockade in idealised one, two and three atom systems. We also include realistic parameter ranges for rubidium as the atomic species. Our results circumvent the doubts cast by recent discussion in the literature (Grangier et al Phys. Rev Lett. 81, 2833 (1998), Imamoglu et al Phys. Rev. Lett. 81, 2836 (1998)) on the possibility of photon blockade in multi-atom systems.Comment: 8 page, revtex, 7 figures, gif. Submitted to Journal of Optics B: Quantum and Semiclassical Optic

‘The International Teacher Leadership project,’ a case of international action research.

Copyright CARNThe paper arises from the International Teacher Leadership project, a research and development project involving researchers and practitioners in 14 European countries. The paper provides a conceptual exploration of the idea of teacher leadership and its role in educational reform, central to which is the idea that teachers, regardless of their level of power and organisational position, can engage in the leadership of enquiry-based development activity aimed at influencing their colleagues and embedding improved practices in their schools. The paper provides an outline of the project’s methodology which builds on that used in the Carpe Vitam Leadership for Learning project (Frost, 2008a). It is a form of collaborative action research which is highly developmental and discursive. It seeks to identify principles, strategies and tools that can be applied in a range of cultural settings. The paper includes a thematic analysis of the cultural contexts and policy environments of the participating countries in order to identify the obstacles to teacher leadership and to inform the nature of the support strategies employed

The role of timing and prototypical causality on how preschoolers fast-map novel verb meanings

In controlled contexts, young children find it more difficult to learn novel words for actions than words for objects: Imai et al. (2008) found that English-speaking three-year-olds mistakenly choose a novel object as a referent for a novel verb about 42% of the time despite hearing the verb in a transitive sentence. The current two studies investigated whether English three- and five-year-old children would find resultative actions easier (since they are prototypically causative) than the non-resultative, durative event types used in Imai et al.’s studies. The reverse was true. Furthermore, if the novel verbs were taught on completion of the action, this did not improve performance, which contrasts with previous findings (e.g. Tomasello & Kruger, 1992). Our resultative actions were punctual, change-of-location events which may be less visually salient than the non-resulative, durative actions. Visual salience may play a greater role than does degree of action causality in the relative ease of verb learning even at three years

Solar-Driven Reduction of Aqueous Protons Coupled to Selective Alcohol Oxidation with a Carbon Nitride-Molecular Ni Catalyst System.

Solar water-splitting represents an important strategy toward production of the storable and renewable fuel hydrogen. The water oxidation half-reaction typically proceeds with poor efficiency and produces the unprofitable and often damaging product, O2. Herein, we demonstrate an alternative approach and couple solar H2 generation with value-added organic substrate oxidation. Solar irradiation of a cyanamide surface-functionalized melon-type carbon nitride ((NCN)CNx) and a molecular nickel(II) bis(diphosphine) H2-evolution catalyst (NiP) enabled the production of H2 with concomitant selective oxidation of benzylic alcohols to aldehydes in high yield under purely aqueous conditions, at room temperature and ambient pressure. This one-pot system maintained its activity over 24 h, generating products in 1:1 stoichiometry, separated in the gas and solution phases. The (NCN)CNx-NiP system showed an activity of 763 μmol (g CNx)(-1) h(-1) toward H2 and aldehyde production, a Ni-based turnover frequency of 76 h(-1), and an external quantum efficiency of 15% (λ = 360 ± 10 nm). This precious metal-free and nontoxic photocatalytic system displays better performance than an analogous system containing platinum instead of NiP. Transient absorption spectroscopy revealed that the photoactivity of (NCN)CNx is due to efficient substrate oxidation of the material, which outweighs possible charge recombination compared to the nonfunctionalized melon-type carbon nitride. Photoexcited (NCN)CNx in the presence of an organic substrate can accumulate ultralong-lived "trapped electrons", which allow for fuel generation in the dark. The artificial photosynthetic system thereby catalyzes a closed redox cycle showing 100% atom economy and generates two value-added products, a solar chemical, and solar fuel.This work was supported by the Christian Doppler Research Association (Austrian Federal Ministry of Science, Research, and Economy and the National Foundation for Research, Technology and Development) and the OMV Group (to E.R.), an Oppenheimer PhD scholarship (to B.C.M.M.), a Marie Curie Postdoctoral Fellowship (GAN 624997 to C.A.C.), a FRQNT Postdoctoral Fellowship (to R.G.), and an ERC Starting Grant (B. V. L., Grant No. 639233).This is the final version of the article. It first appeared from American Chemical Society via http://dx.doi.org/10.1021/jacs.6b0432

Linear optical properties of one-dimensional Frenkel exciton systems with intersite energy correlations

We analyze the effects of intersite energy correlations on the linear optical properties of one-dimensional disordered Frenkel exciton systems. The absorption line width and the factor of radiative rate enhancement are studied as a function of the correlation length of the disorder. The absorption line width monotonously approaches the seeding degree of disorder on increasing the correlation length. On the contrary, the factor of radiative rate enhancement shows a non-monotonous trend, indicating a complicated scenario of the exciton localization in correlated systems. The concept of coherently bound molecules is exploited to explain the numerical results, showing good agreement with theory. Some recent experiments are discussed in the light of the present theory.Comment: 18 pages, 3 figues, REVTeX, to appear in Physical Review

Infrastructures, processes of insertion and the everyday: towards a new dialogue in critical policy studies

This forum argues that the complex assemblages of infrastructures, and their reproduction in our everyday worlds, offer a privileged lens through which to explore the practices of much of what critical policy studies holds dear. It draws attention to processes of insertion that reproduce infrastructure in everyday lives, arguing that such processes cast new light on the work of the state, governance, and democratic struggles. It discerns three avenues as a means of exploring such infrastructural processes: first, an invitation to transcend the physical form and reflect on infrastructural temporalities; second on the transformation of spatial governance and policy through infrastructure; and third, a re-assessment in the relationship between infrastructures and the ‘modernist ideal’. Through these avenues, light can be shed on the often ‘hidden’ practices of policymaking. We conclude by calling for a dialogue across diverse disciplines, side-stepping embedded divides between academics-activists, cities-towns, and the global south-north