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51.
Chris Y. Fang Clive A. Randal Michael T. Lanagan Dinesh K. Agrawal 《Journal of Electroceramics》2009,22(1-3):125-130
Microwave synthesis of nano-sized BaTiO3 and decrystallized titania, and microwave sintering of electroceramics including BaTiO3, Ba(Zn1/3Ta2/3)O3 (BZT), lead zirconate–titanate (i.e. Pb(Zr x Ti1?x )O3, or PZT), etc., as well as multilayer ceramic capacitors based on X7R, C0G, and ferrite multilayer chip inductors are presented. The results indicate that microwave processing significantly accelerated synthesis and sintering kinetics. As a result, processing time can be saved up to 90%, with the product properties comparable to or better than that of the conventional products. 相似文献
52.
Abstract The smaller capitals have larger levels of vehicular travel per head than the larger capitals and are more dependent on private transport, due mainly to greater non-work trip frequencies. Policy approaches are examined for reducing vehicular travel through increasing travel costs, changing land-use patterns and modifying people's values and attitudes to urban vehicular travel. 相似文献
53.
Abstract The paper considers economic effects of increased investment in public transport in Melbourne, based on investment plans of VicRail and the M.M.T.B. over a 5 year period, 1981–5. If the investment were to encourage a shift in patronage from private to public transport, this would change the magnitude of costs associated with passenger transport in Melbourne. Calculations are made of these possible cost savings, given particular levels of shift in patronage. The paper concludes by reviewing the feasibility of achieving given patronage changes. 相似文献
54.
55.
Daniel Kirsten 《Theory of Computing Systems》2006,39(1):15-50
We introduce a new model of weighted automata: the desert automata. We show
that their limitedness problem is PSPACE-complete by solving the underlying
Burnside problem. As an application of this result, we give a positive
solution to the so-called finite substitution problem which was open for more
than 10 years: given recognizable languages K and L, decide whether there
exists a finite substitution σ such that σ(K) = L. 相似文献
56.
This article explores the use of a multimedia search interface for digital libraries based on strand maps developed by the American Association for the Advancement of Science. As semantic-spatial displays, strand maps provide a visual organization of relevant conceptual information that may promote the use of science content during digital library use. A study was conducted to compare users' cognitive processes during information seeking tasks when using a multimedia strand maps interface, versus the textual search interface currently implemented in the Digital Library for Earth System Education. Quantitative and qualitative data from think-aloud protocols revealed that students were more likely to engage with science content (e.g., analyzing the relevance of science concepts with regard to task needs) during search when using the strand maps interface compared to those using textual searching. In contrast, students using a textual search interface engaged more frequently with surface-level information (e.g., the type of a resource regardless of its science content) during search and retrieval. As a multimedia search interface for digital libraries, strand maps appear to be promising tools to promote conceptual discovery and learning through content-based processes that promote learner engagement with relevant science knowledge. 相似文献
57.
Cattle, crops and clearing: Regional drivers of landscape change in the Brigalow Belt, Queensland, Australia, 1840–2004 总被引:1,自引:1,他引:0
Landscape change occurs through the interaction of a multitude of natural and human driving forces at a range of organisational levels, with humans playing an increasingly dominant role in many regions of the world. Building on the current knowledge of the underlying drivers of landscape change, a conceptual framework of regional landscape change was developed which integrated population, economic and cultural values, policy and science/technology. Using the Southern Brigalow Belt biogeographic region of Queensland as a case study, the role of natural and human drivers in landscape change was investigated in four phases of settlement since 1840. The Brigalow Belt has experienced comparable rates of vegetation clearance over the past 50 years to areas of tropical deforestation. Economic factors were important during all phases of development, but the five regional drivers often acted in synergy. Environmental constraints played a significant role in slowing rates of change. Temporal trends of deforestation followed a sigmoidal curve, with initial slow change accelerating though the middle phases then slowing in recent times. Future landscape management needs to take account of the influence of all the components of the conceptual framework, at a range of organisational levels, if more ecologically sustainable outcomes are to be achieved. 相似文献
58.
Studied the role of affect as a mediator of the overjustification effect and proposed that negative affect has a critical detrimental influence on intrinsic motivation, either as a reaction derived from self-perception and evaluation processes or as a factor that acts independently of these cognitive activities. Two studies, with 180 undergraduates, used the typical overjustification paradigm to test these hypotheses. In Exp I, the overjustification effect was successfully replicated for both behavioral and self-report measures of intrinsic motivation. It is important that the negative affect paralleled these results and was greatest in those conditions in which intrinsic motivation was predicted and found to be low (e.g., expected reward). In Exp II, affect was directly manipulated, independently of the cognitive manipulations. Results show that the induced positive affect erased the decrease in intrinsic motivation that was observed in Exp I. It is suggested that what determines the decrease in intrinsic interest in any activity is, in part, the amount of negative affect that becomes associated with the activity. (55 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
59.
Clive W. Bird Muhammad Latif 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1981,31(1):368-370
The principal antibiotics formed by Streptomyces elizabethii have been isolated and identified as actinomycins IV and V, together with a methylpentaene macrolide, elizabethin, stereoisomeric with previously reported compounds. 相似文献
60.
Soren Damgaard-Larsen Kirsten Ottar Jensen Ebba Lund Birte Nissen 《Water research》1977,11(6):503-508
Coxsackievirus and tritiated water were added to municipal sludges which were placed on lysimeters containing sandy soil or clay soil. It took 23 weeks during a normal Danish winter to inactivate virus from an initial 106tcid50/g sludge to a not demonstrable level. Irrespective of sludge and soil type no virus was demonstrated in the leachate water. The rainfall during December–May was 300 mm. 相似文献