1,721,033 research outputs found
Theoretical Investigation Of A Mn-doped Si Ge Heterostructure
Get PDFWe investigate, through ab initio density-functional theory calculations, the electronic and structural properties of neutral Mn impurities at tetrahedral interstitial and substitutional sites in both Si and Ge layers of a Si Ge heterostructure. We conclude that substitutional Mn at the Ge layers is more stable than interstitial Mn at the Si layers by approximately 0.45 eV, and we estimate an energy barrier of at least 1.12 eV to diffuse away from these most stable substitutional sites. Mn has a magnetic moment in the heterostructure that is similar to that in the bulk, and for the compressed Ge layer the Mn-Mn exchange interaction is always weakly antiferromagnetic. Varying the lattice constant of the substrate, the Mn-Mn ground state becomes ferromagnetic. This result opens up the possibility of manipulating the interaction between Mn impurities at Ge layers grown over a Si1-x Gex substrate by changing x. © 2007 The American Physical Society.757Žutić, I., Fabian, J., Das Sarma, S., (2004) Rev. Mod. Phys., 76, p. 323. , RMPHAT 0034-6861 10.1103/RevModPhys.76.323MacDonald, A.H., Schiffer, P., Samarth, N., (2005) Nat. Mater., 3, p. 195. , NMAACR 1476-1122Park, Y.D., Wilson, A., Hanbicki, A.T., Mattson, J.E., Ambrose, T., Spanos, G., Jonker, B.T., (2001) Appl. Phys. Lett., 78, p. 2739. , APPLAB 0003-6951 10.1063/1.1369151Silva Da, R.A.J., Fazzio, A., Antonelli, A., (2004) Phys. Rev. B, 70, p. 193205. , PRBMDO 0163-1829 10.1103/PhysRevB.70.193205Woodbury, H.H., Ludwig, G.W., (1960) Phys. Rev., 117, p. 102. , PHRVAO 0031-899X 10.1103/PhysRev.117.102Nakashima, H., Hashimoto, K., (1991) J. Appl. Phys., 69, p. 1440. , JAPIAU 0021-8979 10.1063/1.347285Kamon, Y., Harima, H., Yanase, A., Katayama-Yoshida, H., (2001) Physica B, 308-310, p. 391. , PHYBE3 0921-4526Perdew, J.P., Wang, Y., (1992) Phys. Rev. B, 45, p. 13244. , PRBMDO 0163-1829 10.1103/PhysRevB.45.13244Vanderbilt, D., (1990) Phys. Rev. B, 41, p. 7892. , PRBMDO 0163-1829 10.1103/PhysRevB.41.7892Kresse, G., Hafner, J., (1993) Phys. Rev. B, 47, p. 558. , PRBMDO 0163-1829 10.1103/PhysRevB.47.558Kresse, G., Furthmüller, J., (1996) Phys. Rev. B, 54, p. 11169. , PRBMDO 0163-1829 10.1103/PhysRevB.54.11169Da Silva, A.J.R., Fazzio, A., Dos Santos, R.R., Oliveira, L.E., (2003) Physica B, 340-342, p. 874. , PHYBE3 0921-4526Da Silva, A.J.R., Fazzio, A., Dos Santos, R.R., Oliveira, L.E., (2004) J. Phys.: Condens. Matter, 16, p. 8243. , JCOMEL 0953-8984 10.1088/0953-8984/16/46/011Venezuela, P., Dalpian, G.M., Silva Da, R.A.J., Fazzio, A., (2001) Phys. Rev. B, 64, p. 193202. , PRBMDO 0163-1829 10.1103/PhysRevB.64.193202Wang, Q., Sun, Q., Jena, P., Kawazoe, Y., (2004) Phys. Rev. Lett., 93, p. 155501. , PRLTAO 0031-9007 10.1103/PhysRevLett.93.15550
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Arsenic segregation, pairing and mobility on the cores of partial dislocations in silicon
No full textFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOWe studied the effects of arsenic on properties of dislocations in silicon. The theoretical investigation was carried out using ab initio total energy methods, based on the density functional theory. We find that the interaction of an arsenic impurity in the crystal with a dislocation results in a charge exchange, driving the dislocation core to a negative charge state. This interaction is essentially electrostatic and attractive, and leads to arsenic segregation. Although arsenic segregation to the core is energetically favourable, formation of arsenic pairs inside the core is energetically unfavourable. We also investigated the role of vacancies in arsenic diffusion inside the dislocation core.We studied the effects of arsenic on properties of dislocations in silicon. The theoretical investigation was carried out using ab initio total energy methods, based on the density functional theory. We find that the interaction of an arsenic impurity in the crystal with a dislocation results in a charge exchange, driving the dislocation core to a negative charge state. This interaction is essentially electrostatic and attractive, and leads to arsenic segregation. Although arsenic segregation to the core is energetically favourable, formation of arsenic pairs inside the core is energetically unfavourable. We also investigated the role of vacancies in arsenic diffusion inside the dislocation core.We studied the effects of arsenic on properties of dislocations in silicon. The theoretical investigation was carried out using ab initio total energy methods, based on the density functional theory. We find that the interaction of an arsenic impurity in the crystal with a dislocation results in a charge exchange, driving the dislocation core to a negative charge state. This interaction is essentially electrostatic and attractive, and leads to arsenic segregation. Although arsenic segregation to the core is energetically favourable, formation of arsenic pairs inside the core is energetically unfavourable. We also investigated the role of vacancies in arsenic diffusion inside the dislocation core.Conference on Extended Defects in Semiconductors (EDS 2002)14481276112765FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOSem informaçãoSem informaçãoQueisser, H.J., Haller, E.E., (1998) Science, 281, p. 945Bulatov, V.V., Justo, J.F., Cai, W., Yip, S., Argon, A.S., Lenosky, T., De Koning, M., Diaz De La Rubia, T., (2001) Phil. Mag. A, 81, p. 1257Patel, J.R., Chaudhuri, A.R., (1966) Phys. Rev., 143, p. 601Patel, J.R., Testardi, L.R., Freeland, P.E., (1976) Phys. Rev. B, 13, p. 3548Suzuki, T., Takeuchi, S., Yoshinaga, H., (1991) Dislocation Dynamics and Plasticity, , (Berlin: Springer)Hirth, J.P., Lothe, J., (1982) Theory of Dislocations, , (New York: Wiley)Alexander, H., Gottschalk, H., (1989) Inst. Phys. Conf. Ser., 104, p. 281Bockstedte, M., Kley, A., Neugebauer, J., Scheffler, M., (1997) Comput. Phys. Commun., 107, p. 187Justo, J.F., De Koning, M., Cai, W., Bulatov, V.V., (2000) Phys. Rev. Lett., 84, p. 2172Justo, J.F., Antonelli, A., Fazzio, A., (2001) Solid State Commun., 118, p. 651Bazant, M.Z., Kaxiras, E., Justo, J.F., (1997) Phys. Rev. B, 56, p. 8542Justo, J.F., Bazant, M.Z., Kaxiras, E., Bulatov, V.V., Yip, S., (1998) Phys. Rev. B, 58, p. 2539Bachelet, G.B., Hamann, D.R., Schluter, M., (1982) Phys. Rev. B, 26, p. 4199Kleinman, L., Bylander, D.M., (1982) Phys. Rev. Lett., 48, p. 1425Antonelli, A., Justo, J.F., Fazzio, A., (2002) J. Appl. Phys., 91, p. 5892Pizzini, S., (1999) Phys. Status Solidi A, 171, p. 123Antonelli, A., Justo, J.F., Fazzio, A., (1999) Phys. Rev. B, 60, p. 4711Fahey, P.M., Griffin, P.B., Plummer, J.D., (1989) Rev. Mod. Phys., 61, p. 289Xie, J., Chen, S.P., (1999) Phys. Rev. Lett., 83, p. 1795Ebert, P., Domke, C., Urban, K., (2001) Appl. Phys. Lett., 78, p. 480Conference on Extended Defects in Semiconductors01 a 06 de Junho de 2002Bologna, ItáliaThis work was partially sponsored by the Brazilian agencies FAPESP and CNPq. Computer calculations were performed at the facilities of the CENAPAD-São Paulo
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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