Efficient field emission properties of ZnO (core)/graphite (shell) nanowires

In this work the field emission studies of a new type of field emitter, zinc oxide (ZnO) core/graphitic (g-C) shell nanowires are presented. The nanowires are synthesized by chemical vapor deposition of zinc acetate at 1300 degrees C Scanning and transmission electron microscopy characterization confirm high aspect ratio and novel core-shell morphology of the nanowires. Raman spectrum of the nanowires mat represents the characteristic Raman modes from g-C shell as well as from the ZnO core. A low turn on field of 2.75 V/mu m and a high current density of 1.0 mA/cm(2) at 4.5 V/mu m for ZnO/g-C nanowires ensure the superior field emission behavior compared to the bare ZnO nanowires. (C) 2012 Elsevier B.V. All rights reserved.

Sapientia, 1990, Vol. XLV, nº 177 (número completo)

Contenido: La prudencia (III) / Octavio Nicolás Derisi – El tránsito de la existencia al ser / Carlos R. Kelz – Arte y conocimiento / Raúl Echauri – Contemplación y Dios en Aristóteles / Beatriz Bossi de Kirchner – Breves notas acerca de la “Política” de Aristóteles / Margarita Mauri Álvarez – La teoría de la ciencia de Guillermo de Ockham: una imagen prospectiva / Olga E. Larre ; J. E. Bolzán – Notas y comentarios -- Bibliografía

Investigations on the vertical migration of planktonic Crustacea in the Bodensee-Obersee. [Translation from: Schriften des Vereins fur Geschichte des Bodensees und seiner Umgebung, 87, 177-187, 1969.]

The vertical zoning of the planktonic Crustacea in a lake is the expression of a complex set of different factors. Besides the measurable, external influences such as light, temperature, acid and C02 stratification, a particularly large part is played by internal factors, which co-ordinate a specific reaction in each species depending on state of development, age and sex. Supporting this extensive, predictable, annual course of diurnal depths and the daily vertical migrations, whose extent is again dependent on external conditions, primarily of course on the amount of light. The individual factors mentioned, however, are here also of great significance. Within the scope of a long-term study of the planktonic Copepoda of Lake Constance, some day and night series were in 1963 also carried out in the Obersee, in order to obtain at least volumetric data on the extent of the daily migrations of these creatures.

Environmentally stable ytterbium figure-of-eight fiber laser producing 177-fs pulses

Pulses of 177 fs and 1035 nm, with average power of 1.2 mW, have been generated directly from a passively mode-locked Yb-doped figure-of-eight fiber laser, with a nonlinear optical loop mirror for mode-locking and pairs of diffraction gratings for intracavity dispersion compensation. To our knowledge, these are the shortest pulses ever to come from a passively mode-locked Yb-doped figure-of-eight fiber laser. This represents a 5-fold reduction in pulse duration compared with that of previously reported passively mode-locked Yb-doped figure-of-eight fiber lasers. Stable pulse trains are produced at the fundamental repetition rate of the resonator, 24.0 MHz. (c) 2007 Elsevier B.V. All rights reserved.

BRS 120 e BRS 177: duas cultivares de trigo de alto potencial de rendimento de grãos para o Sul do Brasil.

2004

C 177 INST-D 2013. 358 Diversos modelos de bolsos y mochilas de hilos de algodón tejidos con las técnicas del chochet y el macramé.

24 fotografías a color.