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101.
Gino Mirocle Crisci Mauro Francesco La Russa Marco Malagodi Silvestro Antonio Ruffolo 《Journal of Cultural Heritage》2010,11(3):304-308
This study is aimed at an assessment of the properties of two polymeric products applied to Norway spruce (Picea abies) and White poplar (Populus alba) wood species. It contributes to ongoing research experiments on the consolidating properties of two synthetic resins and their potential synergic action on wood, resulting from their different interaction with the substrate: Paraloid B72 and Regalrez 1126. Experiments were carried out on a series of samples of the two wood varieties. The consolidants were applied alone and one after the other, with one coat of Regalrez and then one of Paraloid. Porosity and variations in pore size distribution were ascertained by mercury intrusion porosimetry (MIP). Colorimetric and IR spectroscopic measurements were also taken before and after aging by solar radiation and freeze/thaw cycles, to verify the possible slowing of photodegradation of the treated wood and the consolidating resistance. Results confirm that both products penetrate the wood with a different behaviour. After double treatment with Regalrez + Paraloid, a significant advantage was observed in terms of mechanical resistance and pore size distribution, although no advantages as regards resistance to photo-oxidizing processes or colour changes were observed. 相似文献
102.
Control of PDE-ODE cascades with Neumann interconnections 总被引:1,自引:0,他引:1
We extend several recent results on full-state feedback stabilization and state estimation of PDE-ODE cascades, where the PDEs are either of heat type or of wave type, from the previously considered cases where the interconnections are of Dirichlet type, to interconnections of Neumann type. The Neumann type interconnections constrain the PDE state to be subject to a Dirichlet boundary condition at the PDE-ODE interface, and employ the boundary value of the first spatial derivative of the PDE state to be the input to the ODE. In addition to considering heat-ODE and wave-ODE cascades, we also consider a cascade of a diffusion-convection PDE with an ODE, where the convection direction is “away” from the ODE. We refer to this case as a PDE-ODE cascade with “counter-convection.” This case is not only interesting because the PDE subsystem is unstable, but because the control signal is subject to competing effects of diffusion, which is in both directions in the one-dimensional domain, and counter-convection, which is in the direction that is opposite from the propagation direction of the standard delay (transport PDE) process. We rely on the diffusion process to propagate the control signal through the PDE towards the ODE, to stabilize the ODE. 相似文献
103.
104.
Antonio Subirana 《Annals of dyslexia》1964,14(1):45-66
This comprehensive survey by Dr. Subirana of the medical literature and his own experiences in neurological research and practice was prepared for an inter-disciplinary symposium on “Comparative Aspects of Human Communication” held in Austria in September, 1960, by the Wenner-Gren foundation for Anthropological Research. In this paper, Dr. Subirana reviews the facts and theories of the development of cerebral dominance from the snail to the chimpanzee to man, and discusses the medical evidence, from many countries, of the relationship of the two hemispheres of the brain to handedness and to language. His final section relating more specifically to developmental language problems in children will be of special interest to the Orton Society readers. 相似文献
105.
Gianluca Vernillo Aldo Savoldelli Andrea Zignoli Spyros Skafidas Alessandro Fornasiero Antonio La Torre 《Journal of sports sciences》2015,33(19):1998-2005
This study aimed to determine whether the fatigue induced by a mountain ultramarathon (MUM) led to changes in energy cost and kinematic during level and graded running. Pre- and post-race, 14 ultratrail runners ran on a level, uphill (5%) and downhill (5%) treadmill at 10 km · h?1. Kinematic data were acquired using a photocell system. Post-race, the downhill energy cost increased by 13.1% (P < 0.001). No change was noted in level and uphill running. Duty factor and stride frequency were increased, whereas swing time, cycle time and stride length were decreased in all conditions (P < 0.05). Contact time was increased and the rate of force generation was decreased only in the uphill and downhill conditions (P < 0.05). Positive correlations were observed between performance time and the pre- to post-changes in the energy cost of level (r = 0.52, P = 0.04) and uphill running (r = 0.50, P = 0.04). MUM-induced fatigue resulted in physiological and spatiotemporal changes, though the response to fatigue varied considerably between running conditions. These changes resulted in a significant increment only in the downhill energy cost. Incorporating downhill locomotion in the training programmes of ultratrailers may help to improve performance-related physiological and biomechanical parameters. 相似文献
106.
M assimiliano FRALDI Antonio GESUALDO Federico GUARRACINO 《浙江大学学报(A卷英文版)》2014,15(7):482-495
研究目的:研究方法:通过有限元分析和极限分析,研究了在纵向和横向载荷下钢框架的最大负荷和坍塌模式,并考虑了塑性铰链住轴向力和弯曲力矩的作用下住实际旋转时的运动学。在垂直和水平方向载荷共存的情况下,基于轴向力和弯曲力矩的交互作用,研究延性框架的极限载荷和坍塌模式对产生于塑性铰链的真实运动学的敏感性。通过两个基本的案例和通过成功地评估非线性有限元分析和直接实施的极限分析步骤,并利用MATHEMATICA,揭示了其敏感性。
在标准规程的框架下,即使在最简单的案例中,极限分析的主要结果也会考虑在坍塌时的运动学,这与设计和加固的目的都是相关的。如果没有对所有的结构元件的轴向力和弯曲力矩的交互作用进行合理的计算,塑性铰链的定位计算可能得出不正确的坍塌机理和误导性的安全系数。就具体方面而言,本文清楚地表明,在设计新的结构或者为现有结构进行加固时,即使是使用看起来已经非常完备的经典步骤,也必须非常小心。本文的模型可以为处理规程设计的执业工程师和标准化委员会提供参考。 相似文献
107.
This article addresses challenges in accomplishing technology transfer process involving the adaptation and implementation of e-government applications from a donor country to a recipient country. Here it is claimed that prior e-government research has overlooked existing technology transfer literature from the field of knowledge management. This work is aimed at addressing the underlying issues associated with the transfer of e-government technology, given different characteristics of donor and recipient organizations in terms of the socio-economic context and the dynamics of the technological infrastructure. Based on a review, interpretation, and synthesis of a broad range of both technology transfer, e-government and knowledge management literature, we extend the Information Technology Transfer Life-Cycle Model, as this well-known model was derived entirely based on empirical evidence. To this end, we propose a heuristic frame for e-government technology transfer. Finally, five propositions accrued from both the literature review and the proposed heuristic frame are set forth to be further tested, in order to better understand the process dynamics of e-government technology transfer between countries. 相似文献
108.
Marco Antonio Rodriguez 《The Communication Review》2014,17(3):245-255
Aaron the Moor from Titus Andronicus and Ratonhnhaké:ton from Assassin’s Creed III are each aiding in a war against an international superpower, and both characters are plotting ways to advance and improve their respective culture. Aaron is seen as the villain and the antagonist, whereas Ratonhnhaké:ton is seen as an individual who fights for freedom. However, once both characters’ usefulness is exhausted, they are easily characterized as the Other and lose whatever benefits they may have earned. They are tossed aside by the factions they are trying to help. Even though Assassin’s Creed III is a video game, the same issues of colonialism and imperialism can be investigated in this 21st-century genre as in Shakespeare’s play. 相似文献
109.
110.
Traditional Information Retrieval (IR) models assume that the index terms of queries and documents are statistically independent of each other, which is intuitively wrong. This paper proposes the incorporation of the lexical and syntactic knowledge generated by a POS-tagger and a syntactic Chunker into traditional IR similarity measures for including this dependency information between terms. Our proposal is based on theories of discourse structure by means of the segmentation of documents and queries into sentences and entities. Therefore, we measure dependencies between entities instead of between terms. Moreover, we handle discourse references for each entity. It has been evaluated on Spanish and English corpora as well as on Question Answering tasks obtaining significant increases. 相似文献