Analysis of the electric field behavior in the vicinity of a triple junction, using finite elements method computational simulations

The authors studied the electric field behavior in the vicinity of a triple junction, composed by metal, vacuum and dielectric parts, using computational simulations. A bi-dimensional model was constructed using ANSYS MAXWELL to analyze the magnitude of the electric field as a function of the contact angles of the materials. The results showed that a field enhancement or reduction could occur in vacuum for certain contact angles. The influence of the dielectric permittivity was also investigated, and the conclusions showed that the maximum electric field enhancement is proportional to the dielectric permittivity74963101CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPnão temnão temnão te

Analysis Of The Electric Field Behavior In The Vicinity Of A Triple Junction, Using Finite Elements Method Computational Simulations

The authors studied the electric field behavior in the vicinity of a triple junction, composed by metal, vacuum and dielectric parts, using computational simulations. A bi-dimensional model was constructed using ANSYS MAXWELL to analyze the magnitude of the electric field as a function of the contact angles of the materials. The results showed that a field enhancement or reduction could occur in vacuum for certain contact angles. The influence of the dielectric permittivity was also investigated, and the conclusions showed that the maximum electric field enhancement is proportional to the dielectric permittivity.7496101Bergeron, K.D., (1977) J.Appl. Phys., 48, pp. 3073-3080. , http://dx.doi.org/10.1063/1.324077Brodie, I., Schwoebel, P.R., Vacuum microelectronic devices [and prolog] (1994) Proceedings of the IEEE, pp. 1006-1034Chung, M.S., Yoon, B.-G., Cutler, P.H., Miskovsky, N.M., (2004) J.Vac. Sci. Technol. B, 22, pp. 1240-1243. , http://dx.doi.org/10.1116/1.1689309Chung, M.S., Choi, T.S., Yoon, B.-G., (2005) Appl. Surf. Sci., 251 (1-4), pp. 177-181. , http://dx.doi.org/10.1016/j.apsusc.2005.03.107Chung, M.S., Hong, S.C., Cutler, P.H., Miskovsky, N.M., Weiss, B.L., Mayer, A., (2006) J.Vac. Sci. Technol. B, 24, pp. 909-912. , http://dx.doi.org/10.1116/1.2185650Temple, D., Recent progress in field emitter array development for high performance applications (1999) Mater. Sci. Eng. R Reports, 24 (5), pp. 185-239. , http://dx.doi.org/10.1016/S0927-796X(98)00014-XGeis, M.W., (1997) Linc. Lab. J., 10 (1), pp. 3-18Geis, M.W., Efremow, N.N., Krohn, K.E., Twichell, J.C., Lyszczarz, T.M., Kalish, R., Greer, J.A., Tabat, M.D., (1998) Nature, 393, pp. 431-435Kraus, J.D., (1991) Electromagnetics, , Mcgraw-Hill CollegeLatham, R.V., (1983) Vacuum, 33 (6), p. 343. , http://dx.doi.org/10.1016/0042-207X(83)90110-0Lerner, P., Cutler, P.H., Miskovsky, N.M., (1997) J.Vac. Sci. Technol. B, 15, pp. 337-342. , http://dx.doi.org/10.1116/1.589317Schachter, L., Analytic expression for triple-point electron emission from an ideal edge (1998) Appl. Phys. Lett., 72 (4), pp. 421-423Spindt, C.A., Brodie, I., Humphrey, L., Westerberg, E.R., (1976) J.Appl. Phys., 47, pp. 5248-5263. , http://dx.doi.org/10.1063/1.322600Sun, S., Ang, L.K., (2012) J.Appl. Phys., 112. , http://dx.doi.org/10.1063/1.4752712Sze, S.M., (1981) Physics of Semiconductor Devices, , Wiley, New YorkTakuma, T., Field behaviour at a triple junction in composite dielectric arrangements (1991) Electr. Insulat. IEEE Trans., 26 (3), pp. 500-509Takuma, T., Kawamoto, T., Field intensification near various points of contact with a zero contact angle between a solid dielectric and an electrode (1984) Power Apparat. Syst. IEEE Trans., 103 (9), pp. 2486-2494Takuma, T., Kouno, T., Matsuda, H., Field behavior near singular points in composite dielectric arrangements (1978) Electr. Insulat. IEEE Trans., 13 (6), pp. 426-435Tourreil, C.H., Srivastava, K.D., Mechanism of surface charging of high-voltage insulators in vacuum (1973) Electr. Insulat. IEEE Trans., 8 (1), pp. 17-2

Herança da resistência à ferrugem da folha da aveia (Puccinia coronata f. sp. avenae Fraser & Led.) em genótipos brasileiros de aveia branca Inheritance of oat leaf rust (Puccinia coronata f. sp. avenae Fraser & Led.) resistance in white oat brazilian genotypes

A ferrugem da folha da aveia é a moléstia mais importante que ataca a cultura da aveia, ocorrendo em praticamente todas as áreas em que a aveia é cultivada. A forma mais indicada para o seu controle é a utilização de cultivares resistentes. Contudo, para que seja alcançada a resistência durável ao patógeno, é necessário que se conheça a genética da resistência à ferrugem da folha em aveia. O objetivo foi determinar a forma de herança da resistência a três isolados de Puccinia coronata f. sp. avenae Fraser & Led., (coletados no sul do Brasil) em genótipos brasileiros de aveia branca. Para a determinação da herança da resistência a cada um dos três isolados, foram utilizadas populações F2 geradas por meio de cruzamentos artificiais, entre genótipos resistentes (R) e suscetíveis (S) e entre genótipos resistentes (R). Desta forma, foram utilizadas populações F2 dos cruzamentos artificiais entre: i) URPEL 15 (R) x UFRGS 7 (S), UPF 16 (R) x UFRGS 7 (S) e URPEL 15 (R) x UPF 16 (R), para a determinação da herança da resistência ao isolado um (1); ii) URPEL 15 (R) x UFRGS 7 (S), UPF 18 (R) x UFRGS 7 (S) e URPEL 15 (R) x UPF 18 (R), para a determinação da herança da resistência ao isolado dois (2); iii) URPEL 15 (R) x UFRGS 7 (S) e URPEL 15 (R) x UPF 18 (S), para a determinação da herança da resistência ao isolado três (3). Os resultados obtidos evidenciaram que o genótipo URPEL 15 apresenta genes dominantes de resistência aos três isolados de ferrugem da folha da aveia avaliados, que o cultivar UPF 16 apresenta um gene recessivo de resistência ao isolado 1 e o cultivar UPF 18 apresenta um gene recessivo de resistência ao isolado 2. E que os genes de resistência apresentados pelos genótipos URPEL 15, UPF 16 e UPF 18, segregam de forma independente.<br>Oat crown rust is the most important disease for the oat crop, occurring in practically all the areas where oat is cultivated. The most indicated form of control for this disease is the use of resistant cultivars. However, for the durable resistance to be acquired, it is necessary to know the genetics of resistance to crown rust in oats. Thus, the objective of this work was to determine the type of inheritance of resistance to three Puccinia coronata f. sp. avenae Fraser & Led., isolates (collected in southern Brazil) in brazilian white oat genotypes. To determine the inheritance of resistance to each one of three isolates,F2 populations were used generated through artificial crosses, between resistant (R) and susceptible (S) and between resistant genotypes (R). Thus, F2 populations from the following artificial crosses: i) URPEL 15 (R) x UFRGS 7 (S), UPF 16 (R) x UFRGS 7 (S) and URPEL 15 (R) x UPF 16 (R), were used to determine the inheritance of resistance to isolate one (1); ii) URPEL 15 (R) x UFRGS 7 (S), UPF 18 (R) x UFRGS 7 (S) and URPEL 15 (R) x UPF 18 (R), to determine the inheritance of resistance to isolate two (2); iii) URPEL 15 (R) x UFRGS 7 (S) and URPEL 15 (R) x UPF 18 (S), to determine the inheritance of resistance to isolate three (3). The obtained results indicate that the genotype URPEL 15 present dominants genes for resistance to the three oat leaf rust isolates evaluated, the cultivar UPF 16 presents a recessive gene for resistance to isolate 1 and the cultivar UPF 18 has a recessive gene of resistence to isolate 2. Also, the resistance genes presented by genotypes URPEL 15, UPF 16 and UPF 18, segregate in an independent manner