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1.
Ian G. Richardson Adrian R. Brough Rik Brydson Geoffrey W. Groves Christopher M. Dobson 《Journal of the American Ceramic Society》1993,76(9):2285-2288
Solid-state 27 Al and 29 Si magic angle spinning NMR spectroscopy has been combined with electron energy loss spectroscopy carried out in the transmission electron microscope to determine the location of Al substituting in a semicrystalline C-S-H gel present in a hydrated synthetic slag glass. The gel is found to contain mainly pentameric silicate chains in which the central silicon is substituted by aluminum. 相似文献
2.
Erik Mannens Davy Van Deursen Rapha?l Troncy Silvia Pfeiffer Conrad Parker Yves Lafon Jack Jansen Michael Hausenblas Rik Van de Walle 《Multimedia Tools and Applications》2012,59(2):691-715
To make media resources a prime citizen on the Web, we have to go beyond simply replicating digital media files. The Web is based on hyperlinks between Web resources, and that includes hyperlinking out of resources (e.g., from a word or an image within a Web page) as well as hyperlinking into resources (e.g., fragment URIs into Web pages). To turn video and audio into hypervideo and hyperaudio, we need to enable hyperlinking into and out of them. The W3C Media Fragments Working Group is taking on the challenge to further embrace W3C??s mission to lead the World Wide Web to its full potential by developing a Media Fragment protocol and guidelines that ensure the long-term growth of the Web. The major contribution of this paper is the introduction of Media Fragments as a media-format independent, standard means of addressing media resources using URIs. Moreover, we explain how the HTTP protocol can be used and extended to serve Media Fragments and what the impact is for current Web-enabled media formats. 相似文献
3.
Short rotation willow coppice (SRC) and a synthetic biomass, a mixture of the basic biomass components (cellulose, hemicellulose and lignin), have been investigated for the influence of potassium on their pyrolysis behaviours. The willow sample was pre-treated to remove salts and metals by hydrochloric acid, and this demineralised sample was impregnated with potassium. The same type of pre-treatment was applied to components of the synthetic biomass. Characterisation was performed using thermogravimetric analysis with measurement of products by means of Fourier transform infrared spectroscopy (TGA-FTIR) and pyrolysis-gas chromatography-mass spectrometry (PY-GC-MS). A comparison of product distributions and kinetics are reported. While the general features of decomposition of SRC are described well by an additive behaviour of the individual components, there are some differences in the magnitude of the influence of potassium, and on the products produced. For both SRC and the synthetic biomass, TGA traces indicate catalytic promotion of both of the two-stages of biomass decomposition, and potassium can lower the average apparent first-order activation energy for pyrolysis by up to 50 kJ/mol. For both SRC and synthetic biomass the yields and distribution of pyrolysis products have been influenced by the presence of the catalyst. Potassium catalysed pyrolysis increases the char yields markedly and this is more pronounced for synthetic biomass than SRC. Gas evolution profiles during pyrolysis show the same general features for both SRC and synthetic biomass. Relative methane yields increase during the char formation stage of pyrolysis of the potassium doped samples. The evolution profiles of acetic acid and formaldehyde change, and these products are seen in lower relative amounts for both the demineralised samples. A greater variation in pyrolysis products is observed from the treated SRC samples compared to the different synthetic biomass samples. Furthermore, substituted phenols from lignin pyrolysis are more dominant in the pyrolysis profiles of the synthetic biomass than of the SRC, implying that the extracted lignins used in the synthetic biomass yield a greater fraction of monomeric type species than the lignocellulosic cell wall material of SRC. For both types of samples, PY-GS-MS analyses show that potassium has a significant influence on cellulose decomposition markers, not just on the formation of levoglucosan, but also other species from the non-catalysed mechanism, such as 3,4-dihydroxy-3-cyclobutene-1,2-dione. 相似文献
4.
The task of identifying an unknown dynamic system is made easier with prior knowledge on its behaviour. Using a frequency domain approach, the non-parametric maximum likelihood estimator of the system function, associated with the time-dependent impulse response of a time-varying system, is constructed. This is accomplished by the use of a simple linear least squares fitting algorithm, applied to the spectral response of the system to a multisine excitation. The noise variance on the system function is estimated simultaneously, and modelling errors can be detected, as illustrated on a simulation example. 相似文献
5.
Jan De Cock Stijn Notebaert Kenneth Vermeirsch Peter Lambert Rik Van de Walle 《Multimedia Systems》2010,16(2):139-149
In this paper, we examine spatial resolution downscaling transcoding for H.264/AVC video coding. A number of advanced coding
tools limit the applicability of techniques, which were developed for previous video coding standards. We present a spatial
resolution reduction transcoding architecture for H.264/AVC, which extends open-loop transcoding with a low-complexity compensation
technique in the reduced-resolution domain. The proposed architecture tackles the problems in H.264/AVC and avoids visual
artifacts in the transcoded sequence, while keeping complexity significantly lower than more traditional cascaded decoder–encoder
architectures. The refinement step of the proposed architecture can be used to further improve rate-distortion performance,
at the cost of additional complexity. In this way, a dynamic-complexity transcoder is rendered possible. We present a thorough
investigation of the problems related to motion and residual data mapping, leading to a transcoding solution resulting in
fully compliant reduced-size H.264/AVC bitstreams. 相似文献
6.
Davy Van Deursen Wim Van Lancker Erik Mannens Rik Van de Walle 《Multimedia Tools and Applications》2014,70(2):827-846
W3C’s Video in the Web activity aims at a better integration of media within the Web. In this paper, we show how two specifications currently under development within this activity, i.e., Media Fragment URIs and Media Annotations, can be combined within media-enabled HTML5 Web applications. In particular, we introduce a number of extensions for the Media Annotations ontology in order to close the gap with Media Fragment URIs. Additionally, we show how rich media fragment annotations can be converted into a WebVTT file. The latter can be used by HTML5-enabled players to show the annotations in a synchronized way. Further, a fully integrated Web application has been developed that shows how both specifications can work together within an HTML5 environment. This application relies on NinSuna, our media delivery platform targeted at multichannel publication that provides server-side support for both Media Fragment URIs and Media Annotations. 相似文献
7.
8.
Envy is the painful emotion caused by the good fortune of others. This research empirically supports the distinction between two qualitatively different types of envy, namely benign and malicious envy. It reveals that the experience of benign envy leads to a moving-up motivation aimed at improving one’s own position, whereas the experience of malicious envy leads to a pulling-down motivation aimed at damaging the position of the superior other. Study 1 used guided recall of the two envy types in a culture (the Netherlands) that has separate words for benign and malicious envy. Analyses of the experiential content of these emotions found the predicted differences. Study 2 and 3 used one sample from the United States and one from Spain, respectively, where a single word exists for both envy types. A latent class analysis based on the experiential content of envy confirmed the existence of separate experiences of benign and malicious envy in both these cultures as well. The authors discuss the implications of distinguishing the two envy types for theories of cooperation, group performance, and Schadenfreude. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
A method for preserving natural water samples for dissolved oxygen analysis is recommended. The conventional method of using greased glass stoppers have been found to cause an increase in oxygen concentration by 12% over 1-month period as a result of evaporation of water sample through micro-gaps and concurrent intrusion of air into the water sample bottles. Sealing the sample bottles with water has been found to be the optimal storage method. It permits a 100.2 +/- 0.3% recovery of dissolved oxygen concentration from storage seawater samples over 4 months. 相似文献
10.
We present experimental measurements of the C K-ELNES of high temperature pyrolysed graphite and related crystalline materials as a function of collection angle and sample tilt. These results together with a corresponding theoretical analysis indicate that the so-called "magic angle" for EELS measurements of an anisotropic crystal such as graphite, where spectra are independent of sample orientation, is approximately two times the characteristic scattering angle. We briefly discuss the implications of this result for the experimental measurement of anisotropic structures, including interfaces, as well as for the detailed modelling of ELNES structures using advanced electronic structure calculations. 相似文献