1,721,004 research outputs found
Time Resolved Thermal Lens Measurements Of The Thermo-optical Properties Of Nd2o3-doped Low Silica Calcium Aluminosilicate Glasses Down To 4.3 K
No full textIn this work, the thermal lens spectrometry was applied to measure the thermo-optical properties of Nd2O3-doped low silica calcium aluminosilicate glasses as a function of temperature, between 4.3 and 300 K. The thermal relaxation calorimetry was used to determine the specific heat, cp. The results showed a decrease of the thermal diffusivity of about one order of magnitude from 4.3 K up to 300 K, with a T-1 dependence in the interval between 20 and 70 K and a T-0.35 between 4.3 and 20 K. The fluorescence quantum efficiencies of the doped samples were calculated down to 50 K, showing a variation of the order of 12% and 25% for the samples with 0.6 and 1.04 mol% of Nd2O3, respectively. In addition, the temperature corresponding to the maximum in cp/T3, the so-called boson peak, was observed at about 17 K for the undoped sample and at lower temperatures for the doped glasses. In conclusion, our results showed the ability of the time resolved thermal lens to determine the thermo-optical properties of glasses at temperatures lower than 300 K, bringing new possibilities for experiments in a wide range of optical materials. © 2007 Elsevier B.V. All rights reserved.3542-9574579Touloukian, L.R., Powel, R.W., Ho, Y.C., Nicalasu, M.C., (1973) Thermal Diffusivity, , Plenum, New YorkBaesso, M.L., Shen, J., Snock, R.D., (1994) J. Appl. Phys., 75, p. 3732Payne, S.A., Wilke, G.D., Smith, L.K., Krupke, W.F., (1994) Opt. Commun., 111, p. 263Payne, S.A., Marshall, C.D., Bayramian, A., Wilke, G.D., Hayden, J.S., (1995) Appl. Phys. B, 61, p. 257Lima, S.M., Catunda, T., Lebullenger, R., Hernandes, A.C., Baesso, M.L., Bento, A.C., Miranda, L.C.M., (1999) Phys. Rev. B, 60, p. 15173Astrath, N.G.C., Rohling, J.H., Medina, A.N., Bento, A.C., Baesso, M.L., Jacinto, C., Catunda, T., Anjos, V., (2005) Phys. Rev. B, 71, p. 214202Hao, H.Y., Neumann, M., Enss, C., Fleischmann, A., (2004) Rev. Sci. Instrum., 75, p. 2718Shen, J., Lowe, R.D., Snook, R.D., (1992) Chem. Phys., 165, p. 385Shen, J., Baesso, M.L., Snock, R.D., (1994) J. Appl. Phys., 75, p. 3738Rohling, J.H., Pereira, J.R.D., Medina, A.N., Bento, A.C., Baesso, M.L., Sampaio, J.A., Lima, S.M., Miranda, L.C.M., (2003) Rev. Sci. Instrum., 74, p. 291Rohling, J.H., Caldeira, A.M.F., Pereira, J.R.D., Medina, A.N., Bento, A.C., Baesso, M.L., Miranda, L.C.M., Rubira, A.F., (2001) J. Appl. Phys., 89, p. 2220Pereira, J.R.D., Palangana, A.J., Mansanares, A.M., da Silva, E.C., Bento, A.C., Baesso, M.L., (2000) Phys. Rev. E, 61, p. 5410Baesso, M.L., Bento, A.C., Andrade, A.A., Sampaio, J.A., Pecoraro, E., Nunes, L.A.O., Catunda, T., Gama, S., (1998) Phys. Rev. B, 57, p. 10545Bialkowski, S.E., (1996) Photothermal Spectroscopy Methods for Chemical Analysis, , John Wiley, New YorkCaird, J.A., Ramponi, A.J., Staver, P.R., (1991) J. Opt. Soc. Am. B, 8, p. 1391Waxler, R.M., Cleek, G.W., (1973) J. Res. Natl. Bur. Stand.-A Phys. Chem., 77 A, p. 755Medina, A.N., Caldeira, A.M.F., Bento, A.C., Baesso, M.L., Sampaio, J.A., Catunda, T., Gandra, F.G., (2002) J. Non-Cryst. Solids, 304, p. 299Astrath, N.G.C., Steimacher, A., Medina, A.N., Rohling, J.H., Pereira, J.R.D., Bento, A.C., Baesso, M.L., Gandra, F.G., (2006) J. Non-Cryst. Solids, 352, p. 3572Yu, C.C., Freeman, J.J., (1987) Phys. Rev. B, 36, p. 7620Lubchenko, V., Wolynes, P.G., (2003) Proc. Natl. Acad. Sci. USA, 100, p. 1515Sokolov, A.P., Calemczuk, R., Salce, B., Kisliuk, A., Quitmann, D., Duval, E., (1997) Phys. Rev. Lett., 78, p. 2405Pohl, R.O., (2006) J. Non-Cryst. Solids, 352, p. 3363Zeller, R.C., Pohl, R.O., (1971) Phys. Rev. B, 4, p. 2029Masciovecchio, C., Ruocco, G., Sette, F., Krisch, M., Verbeni, R., Bergmann, U., Soltwisch, M., (1996) Phys. Rev. Lett., 76, p. 3356Steimacher, A., Medina, A.N., Bento, A.C., Rohling, J.H., Baesso, M.L., Reynoso, V.C.S., Lima, S.M., Hewak, D.W., (2004) J. Non-Cryst. Solids, 348, p. 240Pecoraro, E., Sampaio, J.A., Nunes, L.A.O., Gama, S., Baesso, M.L., (2000) J. Non-Cryst. Solids, 277, p. 7
Thermo-mechanical And Optical Properties Of Calcium Aluminosilicate Glasses Doped With Er3+ And Yb3+
No full textIn this work a series of Er2O3 and Yb2O3 doped and Er2O3-Yb2O3 co-doped low silica calcium aluminosilicate glasses have been melted at 1470°C under vacuum conditions. Measurements of optical absorption coefficient, mass density, refractive index, Vickers micro-hardness, glass transformation temperature (Tg) and crystallization temperature (Tx) have been carried out. The results showed that these glasses dissolved ∼1.5 mol% Er2O3 and ∼1.1 mol% Yb2O3 in their structure without devitrification and also that only small changes (∼10%) have been measured in their thermal, mechanical and optical properties. © 2000 Elsevier Science B.V. All rights reserved.27301/03/15239245De Souza, D.F., Zonetti, L.F.C., Bell, M.J.V., Sampaio, J.A., Nunes, L.A.O., Baesso, M.L., Bento, A.C., Miranda, L.C.M., (1999) Appl. Phys. Lett., 74, p. 908Auzel, F.E., (1973) Proc. IEEE, 61, p. 758Dwyer, R.M., Bass, M., (1977) Lasers in Medicine, 3, p. 107. , M. Ross (Ed.), Academic Press, New YorkKincade, K., (1996) Laser Focus World, p. 73Neuroth, N., (1987) Opt. Eng., 26, p. 96Weber, M.J., (1990) J. Non-Cryst. Solids, 123, p. 208Davy, J.R., (1978) Glass Technol., 19, p. 32Onoda G.Y., Jr., Brown, S.D., (1970) J. Am. Ceram. Soc., 53, p. 311Shelby, J.E., (1985) J. Am. Ceram. Soc., 68, p. 155Baesso, M.L., Bento, A.C., Duarte, A.R., Neto, A.M., Miranda, L.C.M., Sampaio, J.A., Catunda, T., Gandra, F.C.G., (1999) J. Appl. Phys., 85, p. 8112Tanabe, S., Ohyagi, T., Hanada, T., Soga, N., (1993) J. Ceram. Soc. Jpn., 101, p. 74Abel, T., Harrington, J.A., Foy, P.R., (1994) Appl. Opt., 33, p. 3919Zou, X., Izumitani, T., (1993) J. Non-Cryst. Solids, 162, p. 68Zou, X., Izumitani, T., (1993) J. Ceram. Soc. Jpn., 101, p. 80Zou, X., Izumitani, T., (1993) J. Ceram. Soc. Jpn., 101, p. 85Baesso, M.L., Bento, A.C., Andrade, A.A., Catunda, T., Sampaio, J.A., Gama, S., (1997) J. Non-Cryst. Solids, 219, p. 165Baesso, M.L., Bento, A.C., Andrade, A.A., Sampaio, J.A., Pecoraro, E., Nunes, L.A.O., Catunda, T., Gama, S., (1998) Phys. Rev. B, 57, p. 10545Uhlmann, E.V., Weinberg, M.C., Kreidl, N.J., Burgner, L.L., Zanoni, R., Church, K.H., (1994) J. Non-Cryst. Solids, 178, p. 15Sampaio, J.A., Catunda, T., Gandra, F.C.G., Gama, S., Bento, A.C., Miranda, L.C.M., Baesso, M.L., (1999) J. Non-Cryst. Solids, 247, p. 196Chung, W.J., Yoo, J.R., Kim, Y.S., Heo, J., (1997) J. Am. Ceram. Soc., 80, p. 1485Hafner, H.C., Kreidl, N.J., Weidel, R.A., (1958) J. Am. Ceram. Soc., 41, p. 315Huang, C., Behrman, E.C., (1991) J. Non-Cryst. Solids, 128, p. 310Oprea, C., Togan, D., Popescu, C., (1992) Thermochim. Acta, 194, p. 165Uhlmann, E.V., Weinberg, M.C., Kreidl, N.J., Goktas, A.A., (1993) J. Am. Ceram. Soc., 76, p. 499Shelby, J.E., Slilaty, R.M., (1990) J. Appl. Phys., 68, p. 3207Shelby, J.E., Wierzbicki, M.M., (1995) Phys. Chem. Glasses, 36, p. 17Higby, P.L., Ginther, R.J., Aggarwal, I.D., Friebele, E.J., (1990) J. Non-Cryst. Solids, 126, p. 209Carnall, W.T., Fields, P.R., Rajnak, K., (1968) J. Chem. Phys., 49, p. 2212Vogel, W., (1994) Glass Chemistry, 2nd Ed., p. 411. , Springer, BerlinLucas, L., Chasnthanasinh, M., Poulain, M., Brun, P., Weber, M.J., (1978) J. Non-Cryst. Solids, 27, p. 273Shelby, J.E., Kohli, J.T., (1990) J. Am. Ceram. Soc., 73, p. 39Kohli, J.T., Shelby, J.E., (1991) Phys. Chem. Glasses, 32, p. 67Shelby, J.E., Shaw, C.M., Spess, M.S., (1989) J. Appl. Phys., 66, p. 114
Low Temperature Specific Heat Of Doped And Undoped Glasses
No full textIn this work we have measured the specific heat, cp, of several glasses between 2 and 160 K. The experiments were performed in low silica calcium aluminosilicate (prepared under vacuum and room atmosphere conditions), in silicate and in fluoride glasses. The influence of neodymium, iron and cobalt in cp values at low temperature was also investigated. The scaling proposed by Liu and Löhneysen was used to analyze the experimental data. The temperatures in which the maxima in cp/T3, the so called boson peak, occur are discussed in terms of the Hrubý coefficient, which provides information about the glass forming ability. © 2006 Elsevier B.V. All rights reserved.35232-3535723576Zeller, R.C., Pohl, R.O., (1971) Phys. Rev. B, 4, p. 2029Stephens, R.B., (1973) Phys. Rev. B, 8, p. 2896(1981) Amorphous Solids: Low Temperature Properties, , Phillips W.A. (Ed), Springer, BerlinGil, L., Ramos, M.A., Bringer, A., Buchenau, U., (1993) Phys. Rev. Lett., 70, p. 182Buchenau, U., Prager, M., Nücker, N., Dianoux, A.J., Ahmad, N., Phillips, W., (1986) Phys. Rev. B, 34, p. 5665Anderson, P.W., Halperin, B.I., Varma, C.M., (1972) Philos. Mag., 25, p. 1Phillips, W.A., (1972) J. Low Temp. Phys., 7, p. 351Astrath, N.G.C., Baesso, M.L., Bento, A.C., Colucci, C.C., Medina, A.N., Evangelista, L.R., (2006) Philos. Mag., 86, p. 227Masciovecchio, C., Ruocco, G., Sette, F., Krisch, M., Verbeni, R., Bergmann, U., Soltwisch, M., (1996) Phys. Rev. Lett., 76, p. 3356Sokolov, A.P., Rossler, E., Kisliuk, A., Quitmann, D., (1993) Phys. Rev. Lett., 71, p. 2062Liu, X., Löhneysen, H.v., (1996) Europhys. Lett., 33, p. 617Hrubý, A., (1972) Czech. J. Phys. B, 22, p. 1187Baesso, M.L., Bento, A.C., Andrade, A.A., Sampaio, J.A., Pecoraro, E., Nunes, L.A.O., Catunda, T., Gama, S., (1998) Phys. Rev. B, 57, p. 10545Lima, S.M., Sampaio, J.A., Catunda, T., Lebullenger, R., Hernandes, A.C., Baesso, M.L., Bento, A.C., Gandra, F.C.G., (1999) J. Non-Cryst. Solids, 256-257, p. 337Sokolov, A.P., Calemczuk, R., Salce, B., Kisliuk, A., Quitmann, D., Durval, E., (1997) Phys. Rev. Lett., 72, p. 2405Ramos, M.A., Tálon, C., Vieira, S., (2002) J. Non-Cryst. Solids, 307-310, p. 80Duval, E., Achibat, T., Boukenter, A., Varrel, B., Calemczuk, R., Salce, B., (1999) J. Non-Cryst. Solids, 190, p. 258Angell, C.A., (1995) Science, 267, p. 1924Fisher, R.A., Brodale, G.E., Hornung, E.W., Giauque, W.F., (1968) Rev. Sci. Inst., 39, p. 108Sampaio, J.A., Gama, S., (2004) Phys. Rev. B, 69, p. 104203Baesso, M.L., Bento, A.C., Duarte, A.R., Neto, A.M., Miranda, L.C.M., Sampaio, J.A., Catunda, T., Gandra, F.C.G., (1999) J. Appl. Phys., 85, p. 8112Zimmermann, J., Weber, G., (1981) Phys. Lett., 86, p. 32Pérez-Enciso, E., Ramos, M.A., Vieira, S., (1997) Phys. Rev. B, 56, p. 32Pinango, E.S., Ramos, M.A., Villar, R., Vieira, S., (1990) Basic Features of the Glassy State, p. 509. , Colmenero J., and Alegria A. (Eds), World Scientific, SingaporeTropf, W.J., Thomas, M.E., Harris, T.J., (1995) Handbook of Optics, II, p. 33. , Bass M. (Ed), McGraw-Hill, New YorkSampaio, J.A., Catunda, T., Gandra, F.C.G., Gama, S., Bento, A.C., Miranda, L.C.M., Baesso, M.L., (1999) J. Non-Cryst. Solids, 247, p. 19
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
Thermal Relaxation Method To Determine The Specific Heat Of Optical Glasses
No full textIn this work the thermal relaxation method is applied to determine the specific heat of the following optical glasses: undoped chalcohalides (As2S3 and 40PbI2 + 30Sb2S3 + 30As2S3); undoped and Nd2O3 doped phosphate (38.66P2O5 + 40.22ZnO + 21.12Na2O) and low silica calcium aluminosilicate (47.4CaO + 41.5Al2O3 + 7.0SiO2 + 4.1MgO) glasses. For the latter the samples were melted both under vacuum and air conditions. Our results show that the specific heats of silica calcium aluminosilicate samples prepared under vacuum conditions were larger than that of the samples melted under air atmosphere. For chalcohalide glass sample (40PbI2 + 30Sb2S3 +30As2S3) the occurrence of a glass transition at 171 °C was observed. These results indicate that this simple and low cost method is an useful tool to measure the specific heat of glasses as a function of the temperature. © 2002 Elsevier Science B.V. All rights reserved.3041-3299305Gan, F., (1994) Laser Materials, , World Scientific, SingaporePátek, K., (1970) Glass Lasers, , CRC, OHBaesso, M.L., Bento, A.C., Andrade, A.A., Catunda, T., Pecoraro, E., Nunes, L.A.O., Sampaio, J.A., Gama, S., (1998) Phys. Rev. B., 57, p. 10545Baesso, M.L., Shen, J., Snook, R.D., (1994) J. Appl. Phys., 75, p. 3732Lima, S.M., Catunda, T., Lebullenger, R., Hernandes, A.C., Baesso, M.L., Bento, A.C., Miranda, L.C.M., (1999) Phys. Rev. B., 60, p. 15173Baesso, M.L., Bento, A.C., Andrade, A.A., Catunda, T., Sampaio, J.A., Gama, S., (1997) J. Non-Cryst. Solids, 219, p. 165Baesso, M.L., Bento, A.C., Duarte, A.R., Neto, A.M., Miranda, L.C.M., (1999) J. Appl. Phys., 85, p. 8112Sampaio, J.A., Catunda, T., Gandra, F.C.G., Gama, S., Bento, A.C., Miranda, L.C.M., Baesso, M.L., (1999) J. Non-Cryst. Solids, 247, p. 196Payne, S.A., Marshall, C.D., Bayramian, A., Wilke, G.D., Hayden, J.S., (1995) Appl. Phys. B, 61, p. 257Neuroth, N., (1987) Opt. Eng., 26, p. 96Jewell, J.M., Aggarwal, I.D., (1992) J. Non-Cryst. Solids, 142, p. 260Greason, P., Detrio, J., Bendow, B., Martin, D.J., (1985) Mater. Sci. Forum, 6, p. 607Andrade, A.A., Catunda, T., Lebullenger, R., Hernandes, A.C., Baesso, M.L., (1999) J. Opt. Soc. Am. B, 16, p. 395Andrade, A.A., Catunda, T., Lebullenger, R., Hernandes, A.C., Baesso, M.L., (1998) Elect. Lett., 34, p. 117Bodzenta, J., (1999) Chaos, Solitons Fractal, 10, p. 2087Inamura, Y., Arai, M., Yamamuro, O., Inaba, A., Kitamura, N., Otomo, T., Matsuo, T., Hannon, A.C., (1999) Physica B, 263-264, p. 299Pohl, R.O., Liu, X., Crandall, R.S., (1999) Current Opinion Solid State Mater. Sci., 4, p. 281Talón, C., Ramos, M.A., Vieira, S., (2000) Physica B, 284-288, p. 1155Courtens, E., Foret, M., Hehlen, B., Vacher, R., (2001) Solid State Commun., 117, p. 187Gavin, D.L., Chung, K.-H., Bruce, A.J., Moynihan, C.T., Drexhage, M.G., El Bayoumi, O.H., (1982) Commun. Am. Ceram. Soc., pp. C182Imram, M.M.A., Bhandari, D., Saxena, N.S., (2001) Physica B, 293, p. 394Stewart, G.R., (1983) Rev. Sci. Instrum., 54, p. 1Marone, M.J., Payne, J.E., (1997) Rev. Sci. Instrum., 68, p. 4516Bachmann, R., DiSalvo F.J., Jr., Geballe, T.H., Greene, R.L., Howard, R.E., King, C.N., Kirsch, H.C., Zubeck, R.B., (1972) Rev. Sci. Instrum., 43, p. 205Schutz, R.J., (1974) Rev. Sci. Instrum., 45, p. 548Banerjee, S., Prins, M.W.J., Rajeev, K.P., Raychaudhuri, A.K., (1992) Pramana - J. Phys., 39, p. 391Ema, K., Uematsu, T., Sugata, A., Yao, H., (1993) Jpn. J. Appl. Phys., 32, p. 1846Yao, H., Ema, K., Garland, C.W., (1998) Rev. Sci. Instrum., 69, p. 172Hatta, I., (1979) Rev. Sci. Instrum., 50, p. 292Azechi, L.S., Da Costa, R.F., Medina, A.N., Gandra, F.C.G., (1995) Rev. Fís. Apl. Instrum., 10, p. 70Touloukian, Y.S., Buyco, E.H., (1970) Thermophysical Properties of Matter, 4. , IFI/Plenum, New York, WashingtonHafner, H.C., Kreidel, N.J., (1958) J. Am. Ceram. Soc., 41, p. 315Lima, S.M., Andrade, A.A., Catunda, T., Lebullenger, R., Smektala, F., Jestin, Y., Baesso, M.L., (2001) J. Non-Cryst. Solids, 284, p. 203Hwang, J.S., Lin, K.J., Tien, C., (1997) Rev. Sci. Instrum., 68, p. 94Cao, Z., Lee, B.I., Samuels, W.D., Exarhos, G.J., (2000) J. Phys. Chem. Solids, 61, p. 1677Wagner, T., Kasap, S.O., Vlcek, M., (1998) Thin Solid Films, 317, p. 245Lin, I.C., Navrotsky, A., (1997) J. Non-Cryst. Solids, 215, p. 125Richet, P., Ali Bouhifd, M., Courtial, P., Téqui, C., (1997) J. Non-Cryst. Solids, 211, p. 271Höhne, G., Hemminger, W., Flammershein, H.-J., (1996) Differential Scanning Calorimetry: A Introduction for Practitioners, , Spring, BerlinAvramov, I., Guinev, G., Rodrigues, A.C.M., (2000) J. Non-Cryst. Solids, 271, p. 1
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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