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Gaston A. Goicoechea A. Sevilla J. 《IEEE transactions on instrumentation and measurement》1998,47(5):1129-1132
Luminescent-dye-doped-plastics are nowadays extensively used for esthetic purposes (toys, ballpoint pens, etc.). In the early 1980's, these materials were investigated to be used as sunlight concentrators in energy generation. Recent developments in fiber optic technology, beyond mere data transmission, lead us to consider the feasibility of using such materials for light intensity sensing in fiber optic sensors networks. The sensor described in this work has proved to show high linearity, reproducibility and stability, and low directivity, however it lacks high sensitivity. Further optimization of some design parameters will definitely help to improve it 相似文献
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Alfaro Mde J Alvarez I El Khor S de Padilla FC 《Archivos latinoamericanos de nutrición》2004,54(2):223-228
The functional properties of Caryodendron orinocense protein product were investigated and compared with those of soybean (Glycina maxima). The product protein content was 24.47 g/100 g (Nx6.25). Solubility increased at both sides of the isoelectric point (pH 4.0) and with increased NaCl concentration up to 0.5M. Compared with soybean flour (50% protein), the protein product exhibited higher water and oil absorption, but lower emulsifying activity, emulsion stability, foaming capacity, and foam stability, the last one increase at higher pH. Emulsifying activity, foaming capacity, and foam stability were ionic strength dependent. C. orinocense protein product increased its emulsifying activity steadily from 0.05M to 0.75M NaCl, while it remained almost constant for soybean flour. Foaming capacity increased drastically at pH 10. The minimum time and concentration to form a gel was 20% in 4 min and 10% in 8 min for the Caryodendron protein product and soybean flour, respectively. The bulk density was 0.5056+/-0.0041 g/mL. 相似文献
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Both males and females ofRhabditis pellio release pheromones that attract the opposite sex prior to copulation. A quantitative bioassay for the female-produced pheromone was designed, based on male movement toward a pheromone source placed at one end of a 10-mm strip of bacterial material maintained on nutrient agar in a petri plate. Females produced pheromone from the age at which they attained the adult stage (3 days following hatching from the egg) and maintained a relatively constant production level until at least the ninth day of life. Similarly, males became responsive to the female pheromone by the third day and remained responsive through the ninth day, although the time required for the males to migrate toward a female pheromone source increased with increasing age. No daily rhythm of pheromone responsiveness by males or pheromone production by females was observed when the nematodes were conditioned to a 1212 h light-dark cycle. 相似文献
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Amandeep Singh Gaston Ormazábal Henning Schulzrinne 《Datenschutz und Datensicherheit - DuD》2014,38(1):25-30
In this article, security challenges related to a mobile heterogeneous networking environment, and the general access patterns are discussed. A novel, unified networking architecture that enables secure heterogeneous networking, both in terms of networks and user devices is discussed. A comprehensive security framework providing a generalized authentication scheme using the Extensible Authentication Protocol (EAP) is then presented, by taking into account existing methods for secure network and device access. 相似文献
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Eric Angel Evripidis Bampis Fanny Pascual Alex-Ariel Tchetgnia 《Journal of Scheduling》2009,12(5):437-445
We consider the problem of designing truthful mechanisms for scheduling n tasks on a set of m parallel related machines in order to minimize the makespan. In what follows, we consider that each task is owned by a selfish
agent. This is a variant of the KP-model introduced by Koutsoupias and Papadimitriou (Proc. of STACS 1999, pp. 404–413, 1999) (and of the CKN-model of Christodoulou et al. in Proc. of ICALP 2004, pp. 345–357, 2004) in which the agents cannot choose the machine on which their tasks will be executed. This is done by a centralized authority,
the scheduler. However, the agents may manipulate the scheduler by providing false information regarding the length of their
tasks. We introduce the notion of increasing algorithm and a simple reduction that transforms any increasing algorithm into
a truthful one. Furthermore, we show that some of the classical scheduling algorithms are indeed increasing: the LPT algorithm,
the PTAS of Graham (SIAM J. Appl. Math. 17(2):416–429, 1969) in the case of two machines, as well as a simple PTAS for the case of m machines, with m a fixed constant. Our results yield a randomized r(1+ε)-approximation algorithm where r is the ratio between the largest and the smallest speed of the related machines. Furthermore, by combining our approach with
the classical result of Shmoys et al. (SIAM J. Comput. 24(6):1313–1331, 1995), we obtain a randomized 2r(1+ε)-competitive algorithm. It has to be noticed that these results are obtained without payments, unlike most of the existing
works in the field of Mechanism Design. Finally, we show that if payments are allowed then our approach gives a (1+ε)-algorithm for the off-line case with related machines. 相似文献
9.
Kuan Wang Haoxiang Zhuo Jiantao Wang Fanny Poon Xueliang Sun Biwei Xiao 《Advanced functional materials》2023,33(13):2212607
Branded with low cost and a high degree of safety, with an ambitious aim of substituting lithium-ion batteries in many fields, sodium-ion batteries have received fervid attention in recent years after being dormant for decades. Layered materials are a major focus of study owing to the extensive experience already gained in lithium-ion batteries, and the pursuit of a Mn-rich composition is critical to reduce the cost while retaining the performance. This review provides a timely update of the recent progress of Mn-rich layered materials for sodium-ion batteries based on the understandings of the phase forming principles, structure transformation upon cycling and charge compensation mechanisms and discusses potential ambiguities in the pursuit of high-performance materials. 相似文献
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This study investigated the effectiveness, in terms of the attainment of relevant learning outcomes, of the types of learning promoted by educational features commonly incorporated in course management systems. Twenty-one courses with significant use of the Internet, but with face-to-face teaching as the predominant instructional mode, were investigated. Five hundred and ninety-five students taking these 21 courses completed a questionnaire which gave feedback on the extent of use of and quality of implementation of internet features, as well as their perception of the attainment of outcomes relating to approaches to learning, communication skills and understanding of content. A confirmatory factor analysis of scales pertinent to information presentation and constructive dialogue features showed a very poor fit to the data, indicating that the two types of function did not act in concert. Structural equation modelling was used to test instructional models in presage–process–product format for ‘information’ and ‘dialogue’ features. The information one showed a marginal fit to the data, but the dialogue one a very good fit. This shows that using the Internet for presenting information in a blended environment does not seem to effectively help students achieve learning outcomes. Using features which promote constructive dialogue and interactive learning activities encourages a deep approach to learning, the development of communication skills and enhanced understanding of content. 相似文献