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排序方式: 共有297条查询结果,搜索用时 15 毫秒
71.
Kaustav Sinha Brett Pearson Said R. Casolco Javier E. Garay Olivia A. Graeve 《Journal of the American Ceramic Society》2009,92(11):2504-2511
A novel, integrated, fast, and inexpensive process for the preparation of dense Ba(1− x ) Eu x Al2 Si2 O8 thin ceramic specimens for damage sensor applications is reported. The processing approach involves a combination of combustion synthesis for the preparation of the powders and spark plasma sintering (SPS) for the consolidation of the specimens to densities close to 100% of relative density. The synthesis of the porous powders by combustion resulted in particle (agglomerate) sizes that were on average 421 nm, as determined from dynamic light scattering, and in the almost complete reduction of the initial Eu3+ activators to Eu2+ . The powders densified to grain sizes of around 250 nm due to a collapse of the porous powder structure and minimal grain growth during SPS. Thermal treatment of the powders and sintered specimens improved the intensity of the emissions at 373 and 745 nm and diminished the emission at 485 nm. The luminescence phenomena from the specimens were a result of two mechanisms: (1) the removal of strain in the lattice due to thermal treatment, and (2) a charge transfer mechanism between Eu2+ and Eu3+ . 相似文献
72.
Olivia Jensen 《国际水资源开发杂志》2017,33(1):4-30
This article reviews the development of public–private partnerships (PPP) in water services in Asia over the last two decades and situates the Asian experience within the wider global context. Through a comparative analysis of PPP data from two different sources, the article highlights the critical issue of how ‘private’ is defined in understanding the extent of PPP in Asia, due to the important role played by enterprises under mixed public and private ownership. The article identifies cyclical patterns of development of PPP in the water sector across countries and the use of hybrid contractual and institutional arrangements for PPPs. 相似文献
73.
Maritza Sanchez Katherine A. Acord Samuel Frueh Lisa M. Rueschhoff Olivia A. Graeve 《Advanced Engineering Materials》2023,25(18):2300138
Tantalum carbide (TaC) and hafnium carbide (HfC) have some of the highest melting temperatures among the transition metal carbides, borides, and nitrides, making them promising materials for high-speed flight and high-temperature structural applications. Solid solutions of TaC and HfC are of particular interest due to their enhanced oxidation resistance compared to pure TaC or HfC. This study looks at the effect of Hf content on the oxidation resistance of TaC–HfC sintered specimens. Five compositions are fabricated into bulk samples using spark plasma sintering (2173 K, 50 MPa, 10 min hold). Oxidation behavior of a subset of the compositions (100 vol% TaC, 80 vol% TaC + 20 vol% HfC, and 50 vol% TaC + 50 vol% HfC) is analyzed using an oxyacetylene torch for 60 s. The TaC–HfC samples exhibit a reduction in the oxide scale thickness and the mass ablation rate with increasing HfC content. The improved oxidation resistance can be attributed to the formation of a Hf6Ta2O17 phase. This phase enhances oxidation resistance by reducing oxygen diffusion and serving as a protective layer for the unoxidized material. The superior oxidation resistance of TaC–HfC samples makes these materials strong contenders for the development of high-speed flight coatings. 相似文献
74.
Cognition, Technology & Work - This paper aims to develop a concept of incentive gamification for organizations in the digital era. Incentive gamification is an incentive-based policy using the... 相似文献
75.
Gadelrab Olivia Elmahgary Maryam G. Mahran Abdelrahman M. Ganoub Moustafa Abdellatif Sameh O. 《Journal of Materials Science: Materials in Electronics》2022,33(15):12053-12061
Journal of Materials Science: Materials in Electronics - Various solar cell architectures and materials are currently studied, seeking enhanced photon management mechanisms. Herein, we provide an... 相似文献
76.
Haishan Zhao Olivia J. Osborne Sijie Lin Zhaoxia Ji Robert Damoiseux Yuqiang Wang André E. Nel Shuo Lin 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(32):4404-4411
Recent studies suggest that the nanorods consisting of europium hydroxide could promote angiogenesis. In this study, it is sought to determine if additional types of nanoparticles are capable of enhancing angiogenesis and in addition, understand the underlying mechanisms. For this reason, a method is employed that combines a high throughput in vitro cell based screen coupled with an in vivo validation using vascular specific green fluorescent protein reporter transgenic zebrafish for examining proangiogenesis activity. After screening multiple types of nanoparticles, it is discovered that four of them, EuIII(OH)3 rods (Eu rods), EuIII(OH)3 spheres (Eu spheres), TbIII(OH)3 rods (Tb rods), and TbIII(OH)3 spheres (Tb spheres), are the most effective in promoting angiogenesis. It is also showed that ionic forms of europium nitrate [Eu(NO3)3] (Eu) and terbium nitrate [Tb(NO3)3] (Tb), the two lanthanide elements for these four nanoparticles, are also capable of enhancing angiogenesis. However, this effect is further enhanced by nanoparticle synthesis. Finally, it is demonstrated that reactive oxygen species H2O2 is a key factor in the process of proangiogenesis by lanthanide elemental nanoparticles. 相似文献
77.
Michał Studniarek Ufuk Halisdemir Filip Schleicher Beata Taudul Etienne Urbain Samy Boukari Marie Hervé Charles‐Henri Lambert Abbass Hamadeh Sebastien Petit‐Watelot Olivia Zill Daniel Lacour Loïc Joly Fabrice Scheurer Guy Schmerber Victor Da Costa Anant Dixit Pierre André Guitard Manuel Acosta Florian Leduc Fadi Choueikani Edwige Otero Wulf Wulfhekel François Montaigne Elmer Nahuel Monteblanco Jacek Arabski Philippe Ohresser Eric Beaurepaire Wolfgang Weber Mébarek Alouani Michel Hehn Martin Bowen 《Advanced materials (Deerfield Beach, Fla.)》2017,29(19)
Materials science and device studies have, when implemented jointly as “operando” studies, better revealed the causal link between the properties of the device's materials and its operation, with applications ranging from gas sensing to information and energy technologies. Here, as a further step that maximizes this causal link, the paper focuses on the electronic properties of those atoms that drive a device's operation by using it to read out the materials property. It is demonstrated how this method can reveal insight into the operation of a macroscale, industrial‐grade microelectronic device on the atomic level. A magnetic tunnel junction's (MTJ's) current, which involves charge transport across different atomic species and interfaces, is measured while these atoms absorb soft X‐rays with synchrotron‐grade brilliance. X‐ray absorption is found to affect magnetotransport when the photon energy and linear polarization are tuned to excite Fe? O bonds parallel to the MTJ's interfaces. This explicit link between the device's spintronic performance and these Fe? O bonds, although predicted, challenges conventional wisdom on their detrimental spintronic impact. The technique opens interdisciplinary possibilities to directly probe the role of different atomic species on device operation, and shall considerably simplify the materials science iterations within device research. 相似文献
78.
79.
In this paper, a hybrid approach for image recognition combining type-2 fuzzy logic, modular neural networks and the Sugeno integral is described. Interval type-2 fuzzy inference systems are used to perform edge detection and to calculate fuzzy densities for the decision process. A type-2 fuzzy system is used for edge detection, which is a pre-processing applied to the training data for better use in the neural networks. Another type-2 fuzzy system calculates the fuzzy densities necessary for the Sugeno integral, which is used to integrate results of the neural network modules. In this case, fuzzy logic is shown to be a good methodology to improve the results of a neural system facilitating the representation of the human perception. A comparative study is also made to verify that the proposed approach is better than existing approaches and improves the performance over type-1 fuzzy logic. 相似文献
80.
Acosta-Martin AE Chwastyniak M Beseme O Drobecq H Amouyel P Pinet F 《Proteomics. Clinical applications》2009,3(10):1236-1246
The aim of our study was to analyze the proteomic pattern of human macrophages obtained over a 4 year period from blood donors. The purpose was to simulate a long-term clinical study to assess the application of 2-D DIGE technique for differential proteomic analysis of these scarce samples. Bioinformatic analysis of 2-D DIGE gels of 19 different cultures of macrophages assessed whether they did or did not contain at least specific five spots identified by MS as being or containing bovine deoxyribonuclease I (DNase I). Bovine DNase I was used during sample treatment to remove nucleic acids from protein extracts. Macrophages were classified in two groups, which appeared to be differentiated by the completeness of DNase I treatment. Further detailed analysis revealed a different proteomic pattern of macrophage protein samples according to the completeness of this treatment. The major group of proteins affected, accounting for one third of the differentially expressed proteins, included proteins involved in cell motion and actin cytoskeleton reorganization. The use of DNase I for the removal of nucleic acids from protein samples must be avoided in proteomic studies since it can generate bias in the analysis of protein expression patterns. 相似文献