Highly electron transparent Graphene for field emission triode gates

The enhanced emission performance of a graphene/Mo hybrid gate electrode integrated into a nanocarbon field emission micro-triode electron source is presented. Highly electron transparent gate electrodes are fabricated from chemical vapor deposited bilayer graphene transferred to Mo grids with experimental and simulated data, showing that liberated electrons efficiently traverse multi-layer graphene membranes with transparencies in excess of 50-68%. The graphene hybrid gates are shown to reduce the gate driving voltage by 1.1 kV, whilst increasing the electron transmission efficiency of the gate electrode significantly. Integrated intensity maps show that the electron beam angular dispersion is dramatically improved (87.9°) coupled with a 63% reduction in beam diameter. Impressive temporal stability is noted (<1.0%) with surprising negligible long-term damage to the graphene. A 34% increase in triode perveance and an amplification factor 7.6 times that of conventional refractory metal grid gate electrode-based triodes are noted, thus demonstrating the excellent stability and suitability of graphene gates in micro-triode electron sources. A nanocarbon field emission triode with a hybrid gate electrode is developed. The graphene/Mo gate shows a high electron transparency (50-68%) which results in a reduced turn-on potential, increased beam collimation, reduced beam diameter (63%), enhanced stability (<1% variation), a 34% increase in perveance, and an amplification 7.6 times that of equivalent conventional refractory metal gate triodes. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mode-locked and single-longitudinal-mode waveguide lasers fabricated by femtosecond laser pulses in Er: Yb-doped phosphate glass

Mode-locked and single-longitudinal-mode waveguide lasers, manufactured by femtosecond laser writing in Er-Yb-doped phosphate glasses, are presented. Transform-limited 1.6-ps pulses and a cw output power exceeding 50 mW have been obtained in the two regimes. © 2007 Optical Society of America.

A population of red-transparent, triploid Carassius auratus

A red-transparent population, distributed in Pingxiang of Jiangxi Province, was identified to be triploid Carassius auratus by DNA content measurement and chromosome analysis. Artificial propagation experiments indicated that the red-transparent triploid Carassius auratus could reproduce by gynogenesis. (c) 2005 The Fisheries Society of the British Isles.

Pixel-level tunable liquid crystal lenses for auto-stereoscopic display

Mobile video and gaming are now widely used, and delivery of a glass-free 3D experience is of both research and development interest. The key drawbacks of a conventional 3D display based on a static lenticular lenslet array and parallax barriers are low resolution, limited viewing angle and reduced brightness, mainly because of the need of multiple-pixels for each object point. This study describes the concept and performance of pixel-level cylindrical liquid crystal (LC) lenses, which are designed to steer light to the left and right eye sequentially to form stereo parallax. The width of the LC lenses can be as small as 20-30 μm, so that the associated auto-stereoscopic display will have the same resolution as the 2D display panel in use. Such a thin sheet of tunable LC lens array can be applied directly on existing mobile displays, and can deliver 3D viewing experience while maintaining 2D viewing capability. Transparent electrodes were laser patterned to achieve the single pixel lens resolution, and a high birefringent LC material was used to realise a large diffraction angle for a wide field of view. Simulation was carried out to model the intensity profile at the viewing plane and optimise the lens array based on the measured LC phase profile. The measured viewing angle and intensity profile were compared with the simulation results. © 2014 SPIE.

MEIOTIC CHROMOSOME BEHAVIOR IN FEMALE INTERSEXES OF ARTIFICIAL TRIPLOID TRANSPARENT-COLORED CRUCIAN CARP

Chromosome behavior in meiosis was studied by air-drying, C-banding and surface-spreading methods in female intersexes of artificial triploid transparent-colored crucian carp (Carassius auratus). Chromosome pairing and contraction were obviously asynchronous. The preferential pairing of two homologous chromosomes was the major pattern of chromosome pairing, and a few triple pairing, repeated pairing, telomer or centromere associating and multiple pairing were also observed in the pachytene cells. The metaphase I cells were mainly composed of univalents, bivalents and trivalents, as well as few of other multivalents, such as tetravalents, pentavalents, hexavalents and heptavalents, were also found in some metaphase I cells. The chromosome elements including uni-, bi-, tri- and other multivalents varied considerably among the metaphase I cells, and the associating patterns of multivalents were also diverse. Some 6 n and 12 n cells, in which premeiotic endomitosis occurred once or twice, were found at the prophase and first metaphase of meiosis, and the pairing and associating patterns were basically similar to that of the triploid cells.

Transparent and Light-Emitting Epoxy Super-Nanocomposites Containing ZnO-QDs/SiO2 Nanocomposite Particles as Encapsulating Materials for Solid-State Lighting

In this article, the ZnO quantum dots-SiO2 (Z-S) nanocomposite particles were first synthesized. Transparent Z-S/epoxy super-nanocomposites were then prepared by introducing calcined Z-S nanocomposite particles with a proper ratio of ZnO to SiO2 into a transparent epoxy matrix in terms of the filler-matrix refractive index matching principle. It was shown that the epoxy super-nanocomposites displayed intense luminescence with broad emission spectra. Moreover, the epoxy super-nanocomposites showed the interesting afterglow phenomenon with a long phosphorescence lifetime that was not observed for ZnO-QDs/epoxy nanocomposites. Finally, the transparent and light-emitting Z-S/epoxy super-nanocomposites were successfully employed as encapsulating materials for synthesis of highly bright LED lamps.

First-principles study of p-type transparent conductive oxides CuXO2 (X=Y, Sc, and Al)

Using first-principles methods we have calculated electronic structures, optical properties, and hole conductivities of CuXO2 (X=Y, Sc, and Al). We show that the direct optical band gaps of CuYO2 and CuScO2 are approximately equal to their fundamental band gaps and the conduction bands of them are localized. The direct optical band gaps of CuXO2 (X=Y, Sc, and Al) are 3.3, 3.6, and 3.2 eV, respectively, which are consistent with experimental values of 3.5, 3.7, and 3.5 eV. We find that the hole mobility along long lattice c is higher than that along other directions through calculating effective masses of the three oxides. By analyzing band offset we find that CuScO2 has the highest valence band maximum (VBM) among CuXO2 (X=Y, Sc, and Al). In addition, the approximate transitivity of band offset suggests that CuScO2 has a higher VBM than CuGaO2 and CuInO2 [Phys. Rev. Lett. 88, 066405 (2002)]. We conclude that CuScO2 has a higher p-type doping ability in terms of the doping limit rule. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.2991157]

Research on the influence of fabrication parameters on the performance of buried ion-exchanged glass waveguides using the variational method

The variational method is proposed to analyze the influence of the fabrication parameters on the performance of buried K+-Na+ ion-exchanged Er3+-Yb3+ ions co-doped glass waveguide. The unknown parameters of the Hermite-Gaussian functions as the trial field distribution are determined based on the scalar variational principle. It is demonstrated that the results calculated in this paper agree with those measured in the experiment. The mode dimensions, the effective refractive index, and the overlap factor as the functions of the fabrication parameters are investigated. These results of the variational analysis are useful for the design and optimization of Er3+-Yb3+ ions co-doped waveguides.