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41.
Junying Liu Rui Zhang Itaru Osaka Sarada Mishra Anna E. Javier Detlef‐M. Smilgies Tomasz Kowalewski Richard D. McCullough 《Advanced functional materials》2009,19(21):3427-3434
New solution processable 4‐(2‐hexyldecan)‐4H‐bisthieno[2,3‐d:3′,2′‐b]pyrrole and 4,4′‐dialkyl‐2,2′‐bithiazole‐based copolymers (PBTzDTPs) are synthesized with excellent FET performance. These novel copolymers have considerable potential in printable electronics as they have high charge carrier mobilities, excellent air stability, good solution processibility, and no requirement for post‐deposition thermal annealing, all requirements for this field of application. The thin film transistors fabricated from PBTzDTPs achieve field effect mobilities as high as 0.14 cm2 V?1 s?1 with current on/off ratios up to 106 without thermal annealing. In addition, the devices exhibit stable performance in air, showing no significant degradation over 60 days. Moreover, the polymers described here provide an excellent example of the systems in which higher mobility performance does not require higher crystalline, long‐range ordered structures. Such a system appears to be particularly promising for rapid fabrication techniques, where kinetic conditions usually prevent the development of long‐range order. 相似文献
42.
Determination of 3‐D Alumina Grain Orientation,Size, Shape,and Growth Kinetics from 2‐D Data in Nextel™ 610 Fibers
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Randall S. Hay Geoff E. Fair Kristin A. Keller Travis Tidball 《Journal of the American Ceramic Society》2015,98(7):2295-2306
Nextel? 610 alumina fibers were heat‐treated at 1100°C–1500°C for 1–100 h in air. Grain size distributions (GSDs) and grain orientation distributions (ODs) with respect to the fiber axis were characterized by analysis of TEM images from longitudinal fiber sections. The 2‐D GSDs and ODs were characterized as ellipses. 3‐D GSDs and ODs were calculated by fitting distributions of oriented oblate ellipsoids to 2‐D GSDs and ODs formed by ellipsoid–section‐plane intersections. The standard deviations (SDs) of log‐normal GSDs consistently increased with grain size, which is not diagnostic of normal grain growth. The grain aspect ratio (α) and the tendency of the short grain axis to orient perpendicular to the fiber axis also increased with grain size, resulting in more textured fibers at larger grain sizes. Average 3‐D grain sizes were larger than 2‐D sizes for GSDs with small SDs, but smaller for GSDs with large SDs because of under sampling of small grains. 3‐D grain growth kinetics had the same 815 kJ/mol activation energy as that found by 2‐D analysis, but the grain growth exponent m of 6.0 was larger and the pre‐exponential factor much smaller. Expressions for 3‐D log‐normal GSDs as a function of heat treatment temperature and time were determined. α‐distributions and ODs were determined as a function of grain size. Methods for determining 3‐D GSDs are discussed. 相似文献
43.
Current Understanding of Structure–Processing–Property Relationships in BaTiO3–Bi(M)O3 Dielectrics
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Michaela A. Beuerlein Nitish Kumar Tedi‐Marie Usher Harlan James Brown‐Shaklee Natthaphon Raengthon Ian M. Reaney David P. Cann Jacob L. Jones Geoff L. Brennecka 《Journal of the American Ceramic Society》2016,99(9):2849-2870
As part of a continued push for high permittivity dielectrics suitable for use at elevated operating temperatures and/or large electric fields, modifications of BaTiO3 with Bi(M)O3, where M represents a net‐trivalent B‐site occupied by one or more species, have received a great deal of recent attention. Materials in this composition family exhibit weakly coupled relaxor behavior that is not only remarkably stable at high temperatures and under large electric fields, but is also quite similar across various identities of M. Moderate levels of Bi content (as much as 50 mol%) appear to be crucial to the stability of the dielectric response. In addition, the presence of significant Bi reduces the processing temperatures required for densification and increases the required oxygen content in processing atmospheres relative to traditional X7R‐type BaTiO3‐based dielectrics. Although detailed understanding of the structure–processing–property relationships in this class of materials is still in its infancy, this article reviews the current state of understanding of the mechanisms underlying the high and stable values of both relative permittivity and resistivity that are characteristic of BaTiO3‐Bi(M)O3 dielectrics as well as the processing challenges and opportunities associated with these materials. 相似文献
44.
Geoff Kelly 《Renewable & Sustainable Energy Reviews》2012,16(9):6851-6860
Residential energy consumption is now an important component of total energy consumption and its related emissions. In addition, this consumption has significant potential for growth in both developed and developing countries, as average incomes increase, and domestic appliance numbers rise. Reduction in this energy use may be achieved both through conservation measures, and through increased efficiency in its use. This paper focuses on energy efficiency in appliances—those many devices through which household energy is consumed. The policy instruments available to promote the uptake of more efficient devices, and issues associated with their use, are reviewed, drawing on developed country experiences to date. The instruments available are more limited than in other energy applications, and largely comprise information dissemination, forms of subsidy, and regulation. The last is commonly used in the form of minimum energy performance standards. Assessment of the three instrument types and issues with their use suggests that regulation is the most important measure—albeit with several qualifications on the manner of its use. 相似文献
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47.
Geoff O’Brien 《The International journal of environmental studies》2013,70(1):113-114
The assimilation and subsequent elimination of cobalt‐60 by different marine organisms are affected by the mode of contamination: chronic or acute. Experimental cobalt‐60 Contamination of such organisms varies qualitatively and quantitatively according to whether the pollutant is transferred through the water or through the food. The concentration factor with respect to water, the transfer factor through food and the overall contamination estimate show a decrease for the highest trophic levels. 相似文献
48.
Nguyen Simone P.; McCullough Mary Beth; Noble Ashley 《Canadian Metallurgical Quarterly》2011,103(3):594
The theory–theory account of conceptual development posits that children's concepts are integrated into theories. Concept-learning studies have documented the central role that theories play in children's learning of experimenter-defined categories but have yet to extensively examine complex, real-world concepts, such as health. The present study examined whether providing young children with coherent and causally related information in a theory-based lesson would facilitate their learning about the concept of health. This study used a pretest/lesson/posttest design, plus a 5-month follow-up. Children were randomly assigned to 1 of 3 conditions: theory (i.e., 20 children received a theory-based lesson), nontheory (i.e., 20 children received a nontheory-based lesson), and control (i.e., 20 children received no lesson). Overall, the results showed that children in the theory condition had a more accurate conception of health than children in the nontheory and control conditions, suggesting the importance of theories in children's learning of complex, real-world concepts. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
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50.
Geoff Sutcliffe 《Journal of Automated Reasoning》2009,43(4):337-362
This paper describes the First-Order Form (FOF) and Clause Normal Form (CNF) parts of the TPTP problem library, and the associated
infrastructure. TPTP v3.5.0 was the last release containing only FOF and CNF problems, and thus serves as the exemplar. This
paper summarizes the history and development of the TPTP, describes the structure and contents of the TPTP, and gives an overview
of TPTP related projects and tools. 相似文献