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排序方式: 共有115条查询结果,搜索用时 31 毫秒
61.
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预计2009年美国金属铸件产量将增加2.1%,而从长期增长来看,金属铸件生产量到2018年将以每年1%的增长率增长. 相似文献
63.
Hamden ET Greer F Hoenk ME Blacksberg J Dickie MR Nikzad S Martin DC Schiminovich D 《Applied optics》2011,50(21):4180-4188
We report on the development of coatings for a charged-coupled device (CCD) detector optimized for use in a fixed dispersion UV spectrograph. Because of the rapidly changing index of refraction of Si, single layer broadband antireflection (AR) coatings are not suitable to increase quantum efficiency at all wavelengths of interest. Instead, we describe a creative solution that provides excellent performance over UV wavelengths. We describe progress in the development of a coated CCD detector with theoretical quantum efficiencies (QEs) of greater than 60% at wavelengths from 120 to 300 nm. This high efficiency may be reached by coating a backside-illuminated, thinned, delta-doped CCD with a series of thin film AR coatings. The materials tested include MgF(2) (optimized for highest performance from 120-150 nm), SiO(2) (150-180 nm), Al(2)O(3) (180-240 nm), MgO (200-250 nm), and HfO(2) (240-300 nm). A variety of deposition techniques were tested and a selection of coatings that minimized reflectance on a Si test wafer were applied to functional devices. We also discuss future uses and improvements, including graded and multilayer coatings. 相似文献
64.
Since the end of the 1990s, good quality lighting was that which balanced the needs of humans, economic and environmental issues, and architectural design. Recent studies aimed to find a correlation between environmental lighting and human performance and health, with positive results. What is known, is that insufficient or inappropriate light exposure can disrupt standard human rhythms which may result in adverse consequences for performance, safety, health. By studying the relationship between human physiology and light, research in photobiology has advanced to the point where some attempts to foresee what the lighting practice will be in future. The question is if lighting practice and lighting practitioners are ready for changes. 相似文献
65.
Gustavo Gonalves do Prado Manfredi Cíntia Kazuko Tokuhara Samira Salmeron rika Beatriz Spada de Carvalho Paulo Noronha Liboa‐Filho Carla Andreotti Damante Adriana Campos Passanezi Sant'Ana Mariana Schutzer Ragghianti Zangrando Sebastio Luis Aguiar Greghi Maria Lúcia Rubo de Rezende 《Microscopy research and technique》2019,82(7):1004-1011
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Talma Jordana Lima Neila Lidiany Ribeiro Roberto Germano Costa Geovergue Rodrigues de Medeiros Ariosvaldo Nunes de Medeiros Solange de Sousa Rita de Cassia Ramos do Egypto Queiroga Martina P Serrano Francisco J Barba José M Lorenzo 《Journal of the science of food and agriculture》2019,99(14):6241-6247
68.
Emma
La Malfa Ribolla Giuseppe Giambanco Antonino Spada 《International journal for numerical methods in engineering》2020,121(16):3610-3635
The multiscale homogenization scheme is becoming a diffused tool for the analysis of heterogeneous materials as masonry since it allows dealing with the complexity of formulating closed-form constitutive laws by retrieving the material response from the solution of a unit cell (UC) boundary value problem (BVP). The robustness of multiscale simulations depends on the robustness of the nested macroscopic and mesoscopic models. In this study, specific attention is paid to the meshless solution of the UC BVP under plane stress conditions, comparing performances related to the application of linear displacement or periodic boundary conditions (BCs). The effect of the geometry of the UC is also investigated since the BVP is formulated for the two simpliest UCs, according to a displacement-based variational formulation assuming the block indefinitely elastic and the mortar joints as zero-thickness elasto-plastic interfaces. It will be showed that the meshless discretization allows obtaining some advantages with respect to a standard FE mesh. The influence of the UC morphology as well as the BCs on the linear and nonlinear UC macroscopic response is discussed for pure modes of failure. The results can be constructive in view of performing a general Fe·Meshless or Meshless2 analysis. 相似文献
69.
Galan J.V. Sanchis P. Blasco J. Mart?nez A. Marti J. Fedeli J.M. Jordana E. Gautier P. Perrin M. 《Electronics letters》2009,45(5):262-263
Grating couplers for efficient coupling between silicon sandwiched slot waveguides and standard singlemode fibres are demonstrated. Coupling efficiency up to 20% is experimentally measured for TM polarisation and a wavelength of 1550 nm. A 20 nm 1 dB bandwidth is also obtained. Higher coupling efficiency is expected for particular designs according to simulation results. 相似文献
70.
Jordana Georgin Dison S. P. Franco Fernanda C. Drumm Patrícia Grassi Matias Schadeck Netto Daniel Allasia 《Chemical Engineering Communications》2020,207(10):1368-1379
AbstractThe powdered biomass of paddle cactus (Tacinga palmadora), a rustic plant of great occurrence in the driest regions of Brazil, was evaluated as a low-cost adsorbent to treat textile effluents containing crystal violet (CV) dye. The powdered paddle cactus (PPC) was mainly composed by lignin and holocellulose, as well as, a variety of functional groups. Best results for CV adsorption were found using an adsorbent dosage of 0.5?g L?1 at solution pH equivalent to 10.0. Fast adsorption kinetics was verified, being the equilibrium reached within 100?min, and the curves were well modeled by the pseudo-first-order model. The isotherms were well-represented by the Langmuir model. The maximum adsorption capacity was 228.74?mg g?1 at 328?K. The estimated thermodynamics parameters were ΔG0T?=?328K of –9.08?kJ mol?1, ΔH0 of 12.44?kJ mol?1, and ΔS0 of 0.065?kJ mol?1 K?1. In addition, PPC was able to treat a simulated textile effluent containing organic and inorganic compounds, reaching 93% of color removal efficiency. These findings show that powdered paddle cactus can be applied as potential low-cost adsorbent to treat textile effluents containing CV. 相似文献