1,720,966 research outputs found
Polymer Electrostatics: Detection And Speciation Of Trapped Electric Charges By Electric Probe And Analytical Electron Microscopy
No full textThis work reviews new probe and electron microscopy approaches for the detection of charged domains in insulating polymers, as well as for the identification of the charge-bearing species: scanning electric potential microscopy (SEPM), electric force microscopy (EFM) and energy-loss spectroscopy imaging in the transmission electron microscope (ESI-TEM). The SEPM and EFM micrographs show patterned domains bearing excess electric charges and extending for tens of nanometers, in polymer latex particles and films. The charged species are identified by ESI-TEM as emulsion polymerization initiator and surfactant residues, as well as the associated counter-ions. Charged domains are also observed in common thermoplastic polymers, producing unexpectedly large electric potential gradients.1891526Galembeck, A., Costa, C.A.R., Silva, M.C.V.M., Souza, E.F., Galembeck, F., (2001) Polymer, 42, p. 4845Wu, K., Iedema, M.J., Cowin, J.P., (1999) Science, 286, p. 2482Bauer-Gogonea, S., Gerhard-Multhaupt, R., (1996) IEEE Trans Dielectr Electr Insul, 3, p. 677Malecki, J.A., (1999) Phys Rev B, 59, p. 9954Lacabanne, C., Goyaud, P., Boyer, R.F., (1980) Polym Sci J, 18, p. 277Shrivastava, K., Ranade, J.D., Srivastava, A.P., (1980) Thin Solid Films, 67, p. 201Mudarra, M., Belana, J., Cañadas, J.C., Diego, J.A., (1999) Polymer, 40, p. 2569Skinner, S.M., Svage, R.L., Rutzler J.E., Jr., (1953) Appl Phys J, 24, p. 438Skinner, S.M., (1955) Appl Phys J, 26, p. 509Ribeiro, J.C., (1950) An Acad Bras Cienc, 22, p. 325Eyerer, P., (1972) Adv Colloid Interface Sc, 3, p. 223Rollik, D., Bauer, S., Gerhard-Multhaupt, R., (1999) J Appl Phys, 85, p. 3282Terris, B.D., Stern, J.E., Rugar, D., Mamin, H.J., (1980) J Vac Sci Technol A-Vac Surf Films, 8, p. 374Nonnenmacher, M., O'Boyle, M.P., Wickramasinghe, H.K., (1991) Appl Phys Lett, 58, p. 2921Saurenbach, F., Terris, B.D., (1990) Appl Phys Lett, 56, p. 1703Schmidt, W.F., (1997) Liquid State Electronics of Insulating Liquids, , CRC Press, Boca Raton N.YGalembeck, F., Costa, C.A.R., Galembeck, A., Silva, M.C.V.M., (2001) An AcadBras Cienc, 73, p. 495Moita-Neto, J.M., Monteiro, V.A.R., Galembeck, F., (1996) Colloids Surf A, 108, p. 83Braga, M., Costa, C.A.R., Leite, C.A.P., Galembeck, F., (2001) J Phys Chem B, 105, p. 3005Keslarek, A.J., Costa, C.A.R., Galembeck, F., (2001) Langmuir, 17, p. 7886Cardoso, A.H., Leite, C.A.P., Galembeck, F., (1998) Langmuir, 14, p. 3187Nunes, S.P., Galembeck, F., (1983) J Polym Sci Part C - Polym Lett, 21, p. 49Heinicke, G., (1984) Tribochemistry, , Hanser, Berli
Water Vapor Adsorption Effect On Silica Surface Electrostatic Patterning
No full textThis work verifies a model for the creation and dissipation of reproducible electric potential patterns on silica surfaces, based on water adsorption, ionization, and ion migration under applied electric potential. Samples were thin silica films grown on silicon wafers and partially covered with sets of parallel gold stripe interdigitated electrodes that are normally used for Kelvin force microscope calibration. Noncontact electric potential measurements with a 20 nm spatial resolution were done using the Kelvin method under controlled atmosphere, in an atomic force microscope (AFM) with a Kelvin force attachment (KFM) mounted within an environmental chamber. Patterns were observed in micrographs acquired while one electrode set was biased and the other was grounded and when both were short-circuited and grounded. Electrostatic charging and discharging are much faster at high relative humidity, showing that the charged or discharged silica states are both changed faster under high humidity, while pattern preservation is effective under low humidity. The results are explained considering surface conductance and the partitioning of water cluster ions both in the solid-gas interfaces and the atmosphere, under the biased electrode potential. © 2008 American Chemical Society.112441719317199Schein, L.B., (2007) Science, 316, p. 1572Schein, L.B., (2007) J. Electrost, 65, p. 613Crowley, J.M., (1999) Fundamentals of applied electrostaticsLaplacian Press: Morgan Hill, p. 40. , CATaylor, D.M., Seeker, P.E., (1994) Industrial electrostatics: Fundamentals and measurements, p. 6. , Research Studies Press: EnglandFrenot, A., Chronakis, I.S., (2003) Curr. Opin. Colloid Interface Sci, 8, p. 64http://www.esdjournal.com, Available atChang, J.I., Cheng-Chung, L., (2006) J. Loss. Prev. Process Indust, 19, p. 51Bailey, A.G., (2001) J. Electrost, 51, p. 82Castle, G.S.P., (1997) J. Electrost, 40, p. 13Németh, E., Albrecht, V., Schubert, G., Simon, F., (2003) J. Electrost, 58, p. 3Masuda, H., Yasuda, D., Ema, A., Tanoue, K., (2004) Kona, 22, p. 168Davidson, J.L., Williams, T.J., Bailey, A.G., Hearn, G.L., (2001) J. Electrost, 51, p. 374Castle, G.S.P., Schein, L.B., (1995) J. Electrost, 36, p. 165Chen, G., Tanaka, Y., Takada, T., Zhong, L., (2004) IEEE Trans. Dielectr. Electr. Insul, 11, p. 113McCarty, L.S., Winkleman, A., Whitesides, G.M., (2007) J. Am. Chem. Soc, 129, p. 4075McCarty, L.S., Whitesides, G.M., (2008) Angew. Chem., Int. Ed, 47, p. 2188Hogue, M.D., Buhler, C.R., Calle, C.I., Matsuyama, T., Luo, W., Groop, E.E., (2004) J. Electrost, 67, p. 259Chen, G., Tay, T.Y.G., Davies, A.E., Tanaka, Y., Takada, T., (2001) IEEE Trans. Dielectr. Electr. Insul, 8, p. 867Bigarré, J., Hourquebie, P., (1999) J. Appl. Phys, 85, p. 7443Duff, N., Lacks, D.J., (2008) J. Electrost, 66, p. 51Choi, K.S., Yamaguma, M., Ohsawa, A., (2007) Jpn. J. Appl. Phys, 46, p. 7861Park, A.A., Fan, L.S., (2007) Chem. Eng. Sci, 62, p. 371Nonnenmcher, M., O'Boyle, M.P., Wickramasinghe, H.K., (1991) Appl. Phys. Lett, 58, p. 2921He, T., Ding, H., Peor, N., Naama, P., Lu, M., Corley, D.A., Chen, B., Tour, J.M., (2008) J. Am. Chem. Soc, 130, p. 1699Cheran, L.E., McGovern, M.E., Thompson, M., (2000) Faraday Discuss, 116, p. 23Li, W., Li, D.Y., (2005) J. Chem. Phys, 122, p. 64708Taylor, D.M., Morris, D., Cambridge, J.A., (2004) Appl. Phys. Lett, 85, p. 5266Cheran, L.E., Liess, H.D., Thompson, M., (1999) Analyst, 124, p. 961Keslarek, A.J., Costa, C.A.R., Galembeck, F., (2001) Langmuir, 17, p. 7886Jankov, I.R., Szente, R.N., Goldman, I.D., Carreno, M.N.P., Valle, M.A., Behar, M., Costa, C.A.R., Landers, R., (2005) Surf. Coating Tech, 200, p. 254Jacobs, H.O., Knapp, H.F., Stemmer, A., (1997) Ultramicroscopy, 69, p. 39Jacobs, H.O., Whitesides, G.M., (2001) Science, 291, p. 1763Barry, C.R., Gu, J., Jacobs, H.O., (2005) Nano Lett, 5, p. 2078Galembeck, A., Costa, C.A.R., Silva, M.C.V.M., Souza, E.F., Galembeck, F., (2001) Polymer, 42, p. 4845Braga, M., Costa, C.A.R., Leite, C.A.P., Galembeck, F., (2001) J. Phys. Chem. B, 105, p. 3005Galembeck, F., Costa, C.A.R., Galembeck, A., Silva, M.C.V.M., (2001) Ann. Acad. Bras. Cienc, 73, p. 495Kin, C., Choi, Y.S., Lee, S.M., Park, J.T., Kim, B., Lee, Y.H., (2002) J. Am. Chem. Soc, 124, p. 9906Gouveia, R.F., Costa, C.A.R., Galembeck, F., (2005) J. Phys. Chem. B, 109, p. 4631Bakos, T., Rashkeev, S.N., Pantelides, S.T., (2004) Phys. Rev. B, 69, p. 195206Jacobs, H.O., Knapp, H.F., Stemmer, A., (1999) Rev. Sci. Instrum, 70, p. 1756Jacobs, H.O., Leuchtmann, P., Homan, O.J., Stemmer, A., (1998) J. Appl. Phys, 84, p. 1168Binning, G., Quate, C.F., Gerber, C., (1986) Phys. Rev. Lett, 56, p. 930Galembeck, F., Costa, C.A.R., (2006) Encyclopedia of Surface and Colloid ScienceDekker Encyclopedias, p. 1874. , New YorkFreund, J., Halbritter, J., Hörber, J.K.H., (1999) Microsc. Res. Tech, 44, p. 327Lee, S., Staehle, R.W., (1996) Corros. Sci, 52, p. 843Luna, M., Colchero, J., Gil, A., Gómez-Herrero, J., Baró, A.M., (2000) Appl. Surf. Sci, 157, p. 393Aplin, K.L., (2005) Rev. Sci. Instrum, 76, p. 104501Jacobs, H.O., Patent application publication (2008), US 2008/0160780Barry, C.R., Kortshagen, U., Jacobs, H.O., (2007) Mater. Res. Soc. Symp. Proc, p. 100Soares, L.C., Bertazzo, S., Burgo, T.A.L., Baldim, V., Galembeck, F., (2008) J. Braz. Soc, 19, p. 277Gomollón, J.A., Palau, R., (2005) IEEE Trans. Power Deliv, 20, p. 919Liu, C., Bard, A.J., (2005) Nat. Mater, 7, p. 50
Particle And Polymer Microchemistry And Electric Domain Mapping
No full textNew microscopy techniques are increasing accessible, yielding hitherto unavailable information on the spatial distribution of chemical constituents in sub-micron and nanosized particles, as well as in polymer films and other materials; this work describes four relevant examples. First, elemental distribution maps of a polystyrene latex obtained by electron spectroscopy coupled to transmission microscopy (ESI-TEM) show that particle C/S ratio is highly variable, evidencing the large differences in polymer Mw's, in different particles. Second, electric potential maps of latex macrocrystals obtained by scanning electron potential microscopy (SEPM) show negative large islands dispersed in a positive continuum, with large electric potential gradients. Backscattered electron imaging (BEI) evidences a core-and-shell structure of silica particles: the particles are made out of smaller domains with variable average atomic number, concentrated at the particle outer layers. The fourth example is a complex columnar structure of electric domains, in crystalline alumina, obtained by SEPM.374159166Galembeck, F., Souza, E.F., (1999) Polymers Interfaces and Emulsions, , K. Esumi, M. Dekker: New YorkCardoso, A.H., Leite, C.A.P., Galembeck, F., (1998) Langmuir., 14, p. 3187Terris, B.D., Sterm, J.E., Rugar, D., Mamin, H.J., (1990) J. Vac. Sci. Technol., A, 8, p. 374Goldstein, J.I., Newbury, D.E., Echlin, P., Rimig Jr., D.C., Lyman, C.E., Fiori, C., Lifshin, E., (1992) Scanning Electron Microscopy and X-ray Microanalysis, , New York: PlenumBraga, M., Costa, C.A.R., Leite, C.A.P., Galembeck, F., (2001) J. Phys. Chem. B, 15, p. 3005Galembeck, A., Costa, C.A.R., Da Suva, M.C.V.M., Souza, E.F., Galembeck, F., (2001) Polymer, 11, p. 4845Leite, C.A.P., De Souza, E.F., Galembeck, F., (2001) Jornal of the Brazilian Chemical Society, 12, p. 519Costa, C.A.R., Leite, C.A.P., De Souza, E.F., Galembeck, F., (2001) Langmuir, 17, p. 18
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
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
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