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61.
62.
Mirko Weidner Oscar Borrero-López Mark Hoffman Avi Bendavid 《Thin solid films》2010,518(18):5242-5248
The effect of substrate and surface roughness on the contact fracture of diamond-like carbon coatings on brittle soda-lime glass substrates has been investigated. The average surface roughness (Ra) of the examined samples ranged from 15 nm to 571 nm. Contact damage was simulated by means of spherical nanoindentation, and fracture was subsequently assessed by focused ion beam microscopy. It was found that, in the absence of sub-surface damage in the substrate, fracture occurs in the coating in the form of radial, and ring/cone cracks during loading, and lateral cracks during unloading. Increasing the surface roughness results in a decrease in the critical load for crack initiation during loading, and in the suppression of fracture modes during unloading from high loads. When sub-surface damage (lateral cracks) is present in the substrate, severe spalling takes place during loading, causing a large discontinuity in the load-displacement curve. The results have implications concerning the design of damage-tolerant coated systems consisting of a brittle film on a brittle substrate. 相似文献
63.
Integrated circuit solutions have been one of the enabling technologies, contributing to the success of wireless communications. As the focus of the new generation is moving towards higher bandwidths and new services and applications, challenges for the integrated circuit solutions are ever growing. Development focus has shifted from component design and optimization towards significant system oriented content captured both in the hardware platform and supporting software. This integrated approach challenges existing development models, and affects other disciplines related to wireless system development. This paper explores major challenges for integrated circuit solutions emerging from the system-oriented approach. 相似文献
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• | One major change in the world of international business and finance is the growing role of private equity investments in firms in emerging markets. In little more then four years, since 2003, the money raised by international, primarily American private equity funds for investment in emerging markets went up about ten times, from $3.5B to $35B. |
• | This paper provides a multidimensional analysis and discussion on the role of private equity funds in the globalization process of firms from emerging markets. The discussion begins with development economics, focusing on financial markets development and sector specific capital, proceeds to a discussion of local comparative advantage and intangible trade costs in the process of globalization, and continues with a discussion of imperfect contracts and financial contracting based on recent research in financial economics. |
• | The multidimensional character of the research is congruent with the nature of globalization and international business. Investment of private equity funds in emerging markets is shown as a new form of foreign direct investment dubbed FFDI (financial foreign direct investment). |
68.
We define the convexity rank of a set of points to be the portion of mutually visible pairs of points out of the total number of pairs. Based on this definition of weak convexity, we introduce a spectral method that decomposes a given shape into weakly convex regions. The decomposition is applied without explicitly measuring the convexity rank. The method merely amounts to a spectral clustering of a matrix representing the all‐pairs line of sight. Our method can be directly applied on an oriented point cloud and does not require any topological information, nor explicit concavity or convexity measures. We demonstrate the efficiency of our algorithm on a large number of examples and compare them qualitatively with competitive approaches. 相似文献
69.
Mórocz IA Janoos F van Gelderen P Manor D Karni A Breznitz Z von Aster M Kushnir T Shalev R 《International journal of imaging systems and technology》2012,22(1):81-96
The aim of this article is to report on the importance and challenges of a time-resolved and spatio-temporal analysis of fMRI data from complex cognitive processes and associated disorders using a study on developmental dyscalculia (DD). Participants underwent fMRI while judging the incorrectness of multiplication results, and the data were analyzed using a sequence of methods, each of which progressively provided more a detailed picture of the spatio-temporal aspect of this disease. Healthy subjects and subjects with DD performed alike behaviorally though they exhibited parietal disparities using traditional voxel-based group analyses. Further and more detailed differences, however, surfaced with a time-resolved examination of the neural responses during the experiment. While performing inter-group comparisons, a third group of subjects with dyslexia (DL) but with no arithmetic difficulties was included to test the specificity of the analysis and strengthen the statistical base with overall fifty-eight subjects. Surprisingly, the analysis showed a functional dissimilarity during an initial reading phase for the group of dyslexic but otherwise normal subjects, with respect to controls, even though only numerical digits and no alphabetic characters were presented. Thus our results suggest that time-resolved multi-variate analysis of complex experimental paradigms has the ability to yield powerful new clinical insights about abnormal brain function. Similarly, a detailed compilation of aberrations in the functional cascade may have much greater potential to delineate the core processing problems in mental disorders. 相似文献
70.
Berman Alan Steinberg Suzi Campbell Samuel Ulman Avi Israelachvili Jacob 《Tribology Letters》1998,4(1):43-48
The rational control of the friction and wear (damage) of engineering, as opposed to model, surfaces under practical conditions
such as high contact pressures has long been a technological challenge with much fundamental interest. Lubricant fluids and
physisorbed surfactant monolayers (boundary lubricants) are effective friction modifiers but often fail at high loads. We
show that the chemisorption of a suitably designed single-chained phosphonate surfactant onto crystalline α-alumina surfaces
produces robust protective monolayers that significantly reduce the friction forces and wear even at high loads. The mechanisms
are explained, which point to some general principles that offer a basis for scale-up in many different engineering systems.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献