1,722,018 research outputs found
New Pathways In Plasma Nitriding Of Metal Alloys
No full textIn this paper, we report the effects of oxygen, hydrogen, and deuterium on nitrogen implanted stainless steel AISI 316. The samples were studied in situ by photoemission electron spectroscopy (XPS), nano-indentation (hardness), and scanning electron microscopy (SEM). At relative higher oxygen partial pressures, a surface potential barrier for nitrogen implantation is created by the oxygen absorption. The absorption process obeys a Langmuir isothermal law. The surface barrier is formed by the oxidation of metallic nitrides. The bulk properties such as nitrided layer thickness can be modeled by studying the surface properties. Hydrogen improves the nitrogen content on surface and, consequentially, the hardness in-depth. Surprising efficient oxygen elimination was detected using deuterium instead of hydrogen. This is due to the fact that deuterium improves the nitrogen chemical potential, augmenting the material hardness in depth up to 30% compared to the case when hydrogen is used. This phenomenon is interpreted by an increasing isotope residence time. These novel results suggest that new pathways can be opened in plasma nitriding processes using deuterium in industrial equipment for treatments of metal alloys with stable oxides on the surface. © 2005 Elsevier B.V. All rights reserved.2001-4 SPEC. ISS.498501Deutchman, A.H., Partyka, R.J., Lewis, C., (1989) Conference Proceedings of the ASM - 2nd Int. Conf., p. 29. , T. Spalvins, W.L. Kovacs (Eds.) Cincinnati, OH, USA ASM International Mat. Park, Ohio 44073, USAParascandola, S., Kruse, O., Möller, W., (1999) Appl. Phys. Lett., 75, p. 1851Parascandola, S., Kruse, O., Richter, E., Möller, W., (1999) J. Vac. Sci. Technol., B, 17, p. 855Figueroa, C.A., Ferlauto, A.S., Alvarez, F., (2003) J. Appl. Phys., 94, p. 5435Moller, W., Parascandola, S., Telbizova, T., Gunzel, R., Ritcher, E., (2001) Surf. Coat. Technol., 136, p. 73Figueroa, C.A., Alvarez, F., unpublished resultsFigueroa, C.A., Wisnivesky, D., Alvarez, F., (2002) J. Appl. Phys., 92, p. 764Figueroa, C.A., Wisnivesky, D., Hammer, P., Lacerda, R.G., Droppa Jr., R., Marques, F.C., Alvarez, F., (2001) Surf. Coat. Tech., 405, p. 146Figueroa, C.A., Ochoa, E., Alvarez, F., (2003) J. Appl. Phys., 94, p. 2242Atkins, P.W., (1990) Physical Chemistry, 492. , Fourth Edition Oxford, UK: Oxford University PressKaufman, H.R., (1978) J. Vac. Sci. Technol., 15, p. 272Hammer, P., Victoria, N.M., Alvarez, F., (1998) J. Vac. Sci. Technol., A, Vac. Surf. Films, 16, p. 2491(1998) Multi-Gauge Controller, Manual 6999-08-091, , revision U, December Varian Vacuum Tech., Lexinton, Mass., USAOliver, W.C., Pharr, G.M., (1992) J. Mater. Res., 7, p. 1564Chase Jr., M.W., (1998) NIST-JANAF Thermochemical Tables, (PART I-II). , Phys. J. Chem. Ref. Data, Monograph 9 Fourth EdOchoa, E., Figueroa, C.A., Alvarez, F., Surf. Coat. Technol., , (to be published)Processo de Modificação de superficies metálicas por plasma de nitrogênio e deutério Fernando Alvarez e Carlos Alejandro Figueroa, Brazilian Patent, Instituto Nacional de Propriedade Industrial (INPI), 16-10-03, 10:27 hs, Protocolo #5.030Figueroa, C.A., Alvarez, F., (2004) J. Appl. Phys., 96, p. 7742Levine, I.N., (1995) Physical Chemistry, 824. , Fourth Edition New York, USA: McGraw-Hill, In
The Demand of liquid assets with uncertain lumpy expenditures
No full textWe consider an inventory model for a liquid asset where the per-period net expenditures have two components: one that is frequent and small and another that is infrequent and large. We give a theoretical characterization of the optimal management of liquid asset as well as of the implied observable statistics. We use our characterization to interpret some aspects of households' currency management in Austria, as well as the management of
demand deposits by a large sample of Italian investors
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Structure And Property Relationships Of Amorphous Cncursive Greek Chi: A Joint Experimental And Theoretical Study
No full textAmorphous CNcursive Greek chi and CNcursive Greek chi:H have been prepared by the ion beam assisted deposition technique. Samples were characterized through X-ray and UV photoemission, IR absorption and Raman spectroscopies. These spectra have been interpreted with the aid of quantum chemical calculations based upon the Hartree-Fock theory on several molecular models. The understanding of the electronic and structural properties of the amorphous alloy as a function of nitrogen content could help in the task of synthesizing the metastable silicon-nitride like-phase β-C3N4, a solid which has been predicted to be as hard as diamond. The physical picture emerging from the present study helps to clarify the difficulties in obtaining the crystalline phase of the material, suggesting new experimental directions for syntheses.303499507Wang, E.G., (1997) Prog. Mat. Sci., 41, p. 241Liu, A., Cohen, L., (1989) Science, 245, p. 841Marton, D., Boyd, K.J., Rabalais, J.W., (1995) Int. J. of Modern Phys. B, 9, p. 3527. , and references thereinHammer, P., Victoria, N.M., Alvarez, F., (1999) J. Vac. Technol. A, , submittedSjöström, H., Stasfsröm, S., Boman, M., Sundgren, J.-E., (1995) Phys. Rev. B, 75, p. 1336Hellgren, N., Johansson, M.P., Broitman, E., Hultman, L., Sundgren, J.E., (1999) Phys. Rev. B, 59, p. 5162Dos Santos, M.C., Alvarez, F., (1998) Phys. Rev. B, 58, p. 13918Suenaga, K., (1999) Chem. Phys. Lett., 300, p. 695Terrones, M., (1999) Adv. Mater., 11, p. 655Dewar, M.J.S., Zoebish, E.G., Healy, E.F., Stewart, J.J.P., (1985) J. Am. Chem. Soc., 107, p. 3902Souto, S., Pickholz, M., Dos Santos, M.C., Alvarez, F., (1998) Phys. Rev. B, 57, p. 2536Levine, I.N., (1986) Quantum Chemistry, 3rd Edition, , Allyn and BaconGuo, Y., Goddard III, W.A., (1995) Chem. Phys. Lett., 237, p. 72Lazzaroni, R., Sato, N., Salaneck, W.R., Dos Santos, M.C., Brédas, J.L., Tooze, B., Clark, D.T., (1990) Chem. Phys. Lett., 175, p. 175. , and references thereinAlvarez, F., Dos Santos, M.C., J. Non-Cryst. Solids, , in pressParker, D.H., Chaterjjee, K., Wurz, P., Likke, K.R., Pellin, M.J., Stock, L.M., (1993) The Fullerene, , Edited by: H. W. Kroto, J. E. Fisher, and D. E. Cox, Pergamon Press, Oxford, EnglandHammer, P., Victoria, N.M., Alvarez, F., (1998) J. Vac. Technol. A, 16, p. 2941Souto, S., Alvarez, F., (1997) Appl. Phys. Lett., 70, p. 1539Shirley, D.A., (1972) Phys. Rev. B, 5, p. 4709Alvarez, F., Victoria, N.M., Hammer, P., Freire Jr., F.L., Dos Santos, M.C., (1998) Appl. Phys. Lett., 73, p. 1065Kaufman, J.H., Metin, S., Saperstein, D.D., (1989) Phys. Rev. B, 39, p. 13053Souto, S., Alvarez, F., (1997) Appl. Phys. Lett., 70, p. 1539Alvarez, F., Dos Santos, M.C., Hammer, P., (1998) Appl. Phys. Lett., 73, p. 3521Victoria, N.M., Hammer, P., Dos Santos, M.C., Alvarez, F., Phys. Rev. B, 61. , in pressRobertson, J., (1991) Prog. Solid St. Chem., 21, p. 199Ley, L., (1984) Topics in Applied Physics, Vol 56: The Physics of Hydrogenated Amorphous Silicon II, 56, p. 67. , Editor: J. D. Jonapoulos and G. Lucovsky, Springer-Verlag, Berli
Variations on the Author
Full text link“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
Full text linkWe 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
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