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21.
As in today’s knowledge society the Internet is playing an important role in the information literacy of university students
the goal of this paper is to analyse, after its first year on the Web, the informational impact of an e-learning resource
developed by Granada’s University lecturers (the e-COMS educational portal), a pioneer in Spain for training in information
literacy. From the objective and subjective data provided by the own portal and by it users, two different and complementary
kinds of analysis (functional and users’) are performed. Assessment of various capabilities, among which visibility and usability
stand out, is provided. The highly positive but improvable results offer a detailed analysis of the functional aspects of
the portal itself and of the users’ relations with this information resource. From these analyses strengths and weaknesses
are extracted and some proposals for improvement are derived. 相似文献
22.
Sensitivity analysis of simulations for magnetic particle inspection using the finite-element method 总被引:2,自引:0,他引:2
Lee J.Y. Lee S.J. Jiles D.C. Garton M. Lopez R. Brasche L. 《IEEE transactions on magnetics》2003,39(6):3604-3606
Magnetic particle inspection (MPI) is widely used for nondestructive evaluation in aerospace applications in which interpretation of inspection results is currently limited to empirical knowledge and experience-based approaches. Advances in computational magnetics, particularly the use of finite-element calculations, have enabled realistic numerical simulations of magnetic particle inspection to be undertaken with complicated geometries. In this paper, we report a sensitivity analysis using finite-element-method simulations of magnetic particle inspection for defects with various sizes and geometries. As a result, improved quantitative understanding of the MPI technique and factors that affects its sensitivity and reliability has been achieved. These results can be used to optimize conditions for conducting these inspections and should lead to improvement in analysis and interpretation of experimental results. 相似文献
23.
X-ray photoelectron spectroscopy (XPS) applied to the study of fluorinated polymer surfaces presents several problems related both to peak assignment and to degradation. In this work, we analyse extensively the question of XPS peak assignments in this kind of surfaces. We conclude that in this kind of surfaces using binding energy differences between fluorine and carbon is better than using absolute binding energies. Also a useful relation between fluorine photoelectron energy vs. polymer composition expressed through the atomic ratio fluorine/carbon (F/C) was found. A protocol for data treatment is proposed and applied to a XPS study of the degradation induced by X-ray on high-density polyethylene surfaces modified by direct fluorination. Results obtained for the degradation, namely the atomic ratio F/C obtained by two different methods, combined with angle resolved X-ray photoelectron spectroscopy (ARXPS) were used to study the fluorine concentration profile in depth, producing self-consistent results. 相似文献
24.
The influence of school- and age-related variables was examined separately on 2 tasks involving elementary quantitative skills: conservation of number and mental addition. Performance on these tasks was compared by using a cutoff design with 3 groups of kindergarten and Grade 1 children who differed in age but not amount of schooling (grade), in schooling but not age, or in both age and schooling. The effects of age and schooling were distinct. On conservation of number, performance improved as a function of age but not schooling. On mental arithmetic, accuracy improved with schooling rather than age but children's use of various solution procedures (e.g., retrieval, counting) was not influenced by schooling. Thus, in the domain of elementary mathematical skills, the influence of schooling can be very specific, and age-related variables other than schooling play an important role in the development of elementary mathematical skills. Results illustrate the utility of the cutoff design for investigating instructional and developmental influences on cognitive development. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
25.
The thermal expansion of a titanium modified, swelling resistant austenitic stainless steel designated as D9 is studied by measuring the lattice parameter as a function of temperature in the range 300-1300 K by high-temperature X-ray diffraction technique. The thermal expansion data thus obtained is in reasonable agreement with the typical thermal expansion values reported for similar nuclear grade austenitic stainless steels. However, at temperatures exceeding 900 K, the measured thermal expansivity exhibits a pronounced non-linear increase due partly to the precipitation of complex carbide and intermetallic phases. The high-temperature thermal expansion data obtained in the present study are augmented by modelling the low-temperature thermal expansion behaviour by Grüneisen formalism. 相似文献
26.
Venezuela's vast natural resource base has largely shaped the nation's economic and energy-use patterns. Major opportunities exist for improving the efficiency of energy use in Venezuela and, consequently, restraining the growth of energy-related carbon emissions. This paper presents a detailed report of one potential development path for Venezuela and estimates the ensuing levels of energy demand and CO2 emissions associated with pursuing this path through the year 2025. The results indicate that by adopting a development strategy that incorporates structural changes in the economy, fuel-switching measures and improved end-use efficiencies, Venezuela can introduce energy efficiency and carbon restraints as part of its economic development process. 相似文献
27.
Izard Carroll E.; Fantauzzo Christina A.; Castle Janine M.; Haynes O. Maurice; Rayias Maria F.; Putnam Priscilla H. 《Canadian Metallurgical Quarterly》1995,31(6):997
Four studies examined aspects of the differential emotions theory (DET) hypothesis of expressive behavior development. In Study 1, facial-expressive movements of 108 2.5–9-mo-old infants were video recorded in positive and negative mother–infant interactions (conditions). As expected, Max-specified full-face and partial expressions of interest, joy, sadness, and anger were morphologically stable between the 2 ages. Studies 1 and 2 confirmed predicted differential responding to mother sadness and anger expressions and to composite positive and negative conditions. Discrete negative expressions exceeded negative blends, and the amount of both expression types remained stable across ages. Studies 3 and 4 provided varying degrees of support for the social validity of Max-specified infant negative affect expressions. Conclusions include revisions and clarifications of DET. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
28.
Coupling GIS with Hydrologic and Hydraulic Flood Modelling 总被引:6,自引:1,他引:5
Nunes Correia Francisco Castro Rego Filipe Da Grača Saraiva Maria Ramos Isabel 《Water Resources Management》1998,12(3):229-249
Geographic Information Systems (GIS) have been recognised as a powerful means to integrate and analyse data from various sources in the context of comprehensive floodplain management. As part of this comprehensive approach to floodplain management, it is very important to be able to predict the consequences of different scenarios in terms of flooded areas and associated risk. Hydrologic and hydraulic modelling plays a crucial role and there is much to gain in incorporating these modelling capabilities in GIS. This is still a rather complex task and research is being done on the full integration of these models. Interfacing between these models and GIS may be a very efficient way of overcoming the difficulties and getting very good results in terms of engineering practice. This paper presents results based on the use of Intergraph GIS coupled with Idrisi GIS. Using these two systems substantially increased the flexibility of using GIS as a tool for flood studies. A lumped (XSRAIN) and a distributed (OMEGA) hydrologic models were used to simulate flood hydrographs. The well known HEC-2 Hydraulic model was used to compute flooded areas. These models were applied in the Livramento catchment with very good results. The computation of flooded areas for different flood scenarios, and its representation in GIS, can be used in the assessment of affected property and associated damages. This is a very useful GIS-based approach to floodplain management. 相似文献
29.
The emotional reactivity of rats with lesions of the dorsal portion of medial prefrontal cortex (mPFC) was examined using a classical fear conditioning paradigm. Conditioned fear behavior (freezing responses) was measured during both the acquisition and extinction phases of the task. Lesions enhanced fear reactivity to both the conditioned stimulus (CS) and contextual stimuli during both phases, suggesting that dorsal mPFC lesions produce a general increase in fear reactivity in response to fear conditioning. M. A. Morgan, L. M. Romanski, and J. E. LeDoux (1993) found that lesions just ventral to the present lesions had no effect during acquisition of the same task and prolonged the fear response to the CS (but not the context) during extinction. Thus, both dorsal and ventral regions of mPFC are involved in the fear system, but each modulates different aspects of fear responsivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
30.