939 resultados para 45
Resumo:
Immersion lithography has been considered as the mainstream technology to extend the feasibility of optical lithography to further technology nodes. Using proper polarized illumination in an immersion lithographic tool is a powerful means to enhance the image quality and process capability for high numerical aperture (NA) imaging. In this paper, the impact of polarized illumination on high NA imaging in ArF immersion lithography for 45 nm dense lines and semi-dense lines is studied by PROLITH simulation. The normalized image log slope (NILS) and exposure defocus (ED) window are simulated under various polarized illumination modes, and the impact of polarized illumination on image quality and process latitude is analyzed. (C) 2007 Elsevier GmbH. All rights reserved.
Resumo:
A method for the control of polarization for a broadband dichroic filter was reported and some design examples were elaborated. This method could be applied over a wide range of wavelengths and a wide range of polarizations in the transmission region. A nonpolaiizing broadband dichroic filter and a broadband dichroic filter with certain polarization were designed and fabricated by electron beam evaporation with ion beam assisted deposition. The experimental spectral performances showed good agreement with their theoretical curves. In addition, the application of the method was discussed. (c) 2007 Optical Society of America
Resumo:
A presente dissertação se propõe a analisar a política brasileira de propaganda e difusão cultural entre os anos de 1937 e 1945, isto é, durante o regime autoritário do Estado Novo. Como objetos de estudo, elegemos as atividades do Departamento de Imprensa e Propaganda e da Divisão de Cooperação Intelectual do Itamaraty, com ênfase no uso dos principais veículos de comunicação da época. De modo complementar, abordamos a influência da Política de Boa Vizinhança nas Américas e as viagens ao estrangeiro de artistas e intelectuais nacionais. Nosso objetivo é provar que, nesse período, o Brasil desenvolveu uma política sistemática de promoção da cultura nacional, visando exportar a imagem de um país em ascensão imagem, essa, correspondente às aspirações brasileiras de desenvolvimento e afirmação junto às grandes nações do mundo.
Resumo:
Single grain, (RE)BCO bulk superconductors in large or complicated geometries are required for a variety of potential applications, such as motors and generators and magnetic shielding devices. As a result, top, multi-seeded, melt growth (TMSMG) has been investigated over the past two years in an attempt to enlarge the size of (RE)BCO single grains specifically for such applications. Of these multi-seeding techniques, so-called bridge seeding provides the best alignment of two seeds in a single grain growth process. Here we report, for the first time, the successful growth of YBCO using a special, 45{\deg} - 45{\deg}, arrangement of bridge-seeds. The superconducting properties, including trapped field, of the multi-seeded YBCO grains have been measured for different bridge lengths of the 45{\deg}- 45{\deg} bridge-seeds. The boundaries at the impinging growth front and the growth features of the top, multi-seeded surface and cross-section of the multi-seeded, samples have been analysed using optical microscopy. The results suggest that an impurity-free boundary between the two seeds of each leg of the bridge-seed can form when 45{\deg}- 45{\deg} bridge-seeds are used to enlarge the size of YBCO grains.
Resumo:
A variety of multiseeding techniques have been investigated over the past 20 yr in an attempt to enlarge bulk (RE)BCO superconducting samples fabricated by the top-seeded melt growth (TSMG) process for practical applications. Unfortunately, these studies have failed to establish whether technically useful values of trapped field can be achieved in multiseeded bulk samples. In this work specially designed, 0°-0° and 45°-45° bridge seeds of different lengths have been employed to produce improved alignment of the seeds during the TSMG process. The ability of these bridge-seeded samples to trap magnetic field, which is the key superconducting property for practical applications of bulk (RE)BCO, is compared for the samples seeded using 0°-0° and 45°-45° bridge seeds of different lengths. The grain boundaries produced by these bridge seeds are analyzed in detail, and the similarities and differences between the two bridge-seeding processes are discussed. © 2013 The American Ceramic Society.
Resumo:
Optimized AlGaN/AlN/GaN high electron mobility transistor (HEMT) with high mobility GaN channel layer structures were grown on 2-in. diameter semi-insulating 6H-SiC substrates by MOCVD. The 2-in. diameter GaN HEMT wafer exhibited a low average sheet resistance of 261.9 Omega/square, with the resistance un-uniformity as low as 2.23%. Atomic force microscopy measurements revealed a smooth AlGaN surface whose root-mean-square roughness is 0.281 nm for a scan area of 5 x 5 mu m. For the single-cell HEMTs device of 2.5-mm gate width fabricated using the materials, a maximum drain current density of 1.31 A/mm, an extrinsic transconductance of 450 mS/mm, a current gain cutoff frequency of 24 GHz and a maximum frequency of oscillation 54 GHz were achieved. The four-cell internally-matched GaN HEMTs device with 10-mm total gate width demonstrated a very high output power of 45.2 W at 8 GHz under the condition of continuous-wave (CW), with a power added efficiency of 32.0% and power gain of 6.2 dB. To our best knowledge, the achieved output power of internally-matched devices are the state-of-the-art result ever reported for X-band GaN-based HEMTs. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.
Resumo:
讨论了一种类似蜂窝或V型膜的玻璃盖板与45°膜复合结构(简称45°膜结构)的光热性能。其透过率比蜂窝结构高,隔热性能与蜂窝结构和V型膜结构相当,在低纬地区应用效果甚好。