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101.
Carbon nanohorns (CNHs) functionalized with aryl units, possessing ethylene glycol chains terminated to amine groups, were condensed with modified C60 carrying a free carboxylic acid group. Direct evidence for the covalent functionalization of CNHs was given by high-resolution transmission electron microscopy (HR-TEM) imaging of C60 present in that CNH hybrid material. In addition, it was found that C60 remained unaffected even after prolonged exposure to the electron beam. Finally, monitoring the wave motion of the connecting ethylene glycol chains, through sequential HR-TEM images, further proved the stability of the covalent bond that links the two carbon nanostructures. 相似文献
102.
Nikos Sioumis Stamatina Kallithraka Epaminondas Tsoutsouras Dimitris P. Makris Panagiotis Kefalas 《European Food Research and Technology》2005,220(3-4):326-330
Browning is a serious problem in relation to white wine quality and mostly affects the sensory attributes, whereas its impact on the dietary value of wines has never been investigated. Browning, however, is well known to be associated with polyphenol oxidation, and therefore it may be accompanied by changes in the antioxidant capacity. On the basis of this consideration, experimental white wines vinified and stored under identical conditions were subjected to accelerated browning, and efforts were made to distinguish compositional parameters that might be related to the extent of browning development. Further, the consequences of browning on the reducing power and antiradical activity were assessed. It was shown that none of the parameters examined (titratable acidity, pH, total SO2, total polyphenols and total flavanols) play an important role in browning onset, but SO2 appeared to exert a statistically significant influence (r2=0.6394, P<0.05) on the percentage change in the antiradical activity. Evidence also suggested that browning development might be prominently associated with decreases in both antiradical activity (r2=0.7891, P<0.01) and reducing power (r2=0.6925, P<0.05). 相似文献
103.
Kostas Kandylis Panayiotis Nikokyris Dimitrios Liamadis Kostas Deligiannis 《Journal of the science of food and agriculture》1992,58(3):291-299
The value of cotton seed cake as a source of crude protein in sheep diets was studied. The cotton seed cake was incorporated into diets at levels of 0, 15 and 30% after replacement of soya bean meal and was fed ad libitum to growing lambs. The diets were formulated to be isonitrogenous and isocaloric. Sixteen lambs (8 male and 8 female) having an average liveweight of approximately 13.6 kg were used in each treatment. After being fed for 62 days and having reached a liveweight of approximately 26.7 kg, five male lambs from each treatment were slaughtered and carcass data were collected. Results of the growth trial showed that there were no significant differences in feedlot performance or carcass analysis among the lambs fed these diets. The dressing percentage was slightly higher (P > 0.05) for lambs fed the 15% cotton seed cake compared with the 30% cotton seed cake and control diets. However, the final weights were substantially higher (P < 0.001) and live average daily gains and feed intakes were all higher (P < 0.10) for male animals. It was concluded that cotton seed cake is an acceptable feed ingredient for growing sheep and can satisfactorily replace soya bean meal as a source of protein in ruminant diets, a feedstuff locally produced in Greece and substantially cheaper than the imported soya bean meal. 相似文献
104.
Nikos Tziritas Spyros Lalis Samee Ullah Khan Thanasis Loukopoulos Cheng-Zhong Xu Petros Lampsas 《Mobile Networks and Applications》2013,18(5):622-638
The mobile agent paradigm has been adopted by several systems in the area of wireless sensor networks as it enables a flexible distribution and placement of application components on nodes, at runtime. Most agent placement and migration algorithms proposed in the literature, assume that the communication rates between agents remain stable for a sufficiently long time to amortize the migration costs. Then, the problem is that frequent changes in the application-level communication may lead to several non-beneficial agent migrations, which may actually increase the total network cost, instead of decreasing it. To tackle this problem, we propose two distributed algorithms that take migration decisions in an online fashion, trying to deal with fluctuations in agent communication. The first algorithm is more of theoretical value, as it assumes infinite storage to keep information about the message exchange history of agents, while the second algorithm is a refined version that works with finite storage and limited information. We describe these algorithms in detail, and provide proofs for their competitive ratio vs. an optimal oracle. In addition, we evaluate the performance of the proposed algorithms for different parameter settings through a series of simulated experiments, also comparing their results with those achieved by an optimal static placement that is computed with full (a posteriori) knowledge of the execution scenarios. Our theoretical and experimental results are a strong indication for the robustness and effectiveness of the proposed algorithms. 相似文献
105.
Hydroazafullerene C59HN was studied by vibrational infra-red and Raman spectroscopy and its thermal stability was examined. Fingerprints modes were identified and unambiguously differentiate it from bisazafullerene. At 700 K full transformation to bisazafullerene occurred, while an intermediate metastable phase was identified at 540 K showing different spectra where the splitting of most of the lines is strongly reduced. 相似文献
106.
This study estimates hydrological drought characteristics using a water balance derived drought index in Pinios river basin, Thessaly, Greece. The concept of hydrological management at subwatershed scale has been adopted because it encompasses the areal extent of a drought event. Fourteen (14) sub-watersheds of Pinios river basin were delineated according to the major tributaries of Pinios river using GIS. For the assessment of hydrological drought, because none of the sub-watersheds have flow gauge stations at their outlets, a six-parameter monthly conceptual water balance model (UTHBAL model), has been applied regionally to simulate runoff for the period October 1960?CSeptember 2002. The synthetic runoff was normalized through Box-Cox transformation and standardized to the mean runoff to produce the water balance derived drought index for hydrological drought assessment. The standardized precipitation index (SPI) at multiple time scales and four indices of the Palmer method (i.e. PDSI, WPLM, PHDI and the Palmer moisture anomaly Z-index) were also calculated to assess hydrological droughts. The results showed that the water balance derived drought index is a good indicator of hydrological drought in all sub-watersheds, since is capable to quantify drought severity and duration. Furthermore, the drought index provides guidance on the selection of an appropriate meteorological drought index for operational hydrological drought monitoring. Hence, SPI at 3- and 6-month timescales and the WPLM could be used along with the water balance derived drought index in risk and decision analyses at the study area. 相似文献
107.
Hyun‐Cheol Kim Charalampos Z. Patrikakis Nikos Minogiannis Pantelis N. Karamolegkos Alex Lambiris Kyuheon Kim 《ETRI Journal》2006,28(4):411-424
This paper presents a multimedia streaming platform for efficiently transmitting MPEG‐4 content over IP networks. The platform includes an MPEG‐4 compliant streaming server and client, supporting object‐based representation of multimedia scenes, interactivity, and advanced encoding profiles defined by the ISO standard. For scalability purposes, we employ an application‐layer multicast scheme for media transmission using overlay networks. The overlay network, governed by the central entity of the network distribution manager, is dynamically deployed according to a set of pre‐defined criteria. The overlay network supports both broadcast delivery and video‐on‐demand content. The multimedia streaming platform is standards‐compliant and utilizes widespread multimedia protocols such as MPEG‐4, real‐time transport protocol, real‐time transport control protocol, and real‐time streaming protocol. The design of the overlay network was architected with the goal of transparency to both the streaming server and the client. As a result, many commercial implementations that use industry‐standard protocols can be plugged into the architecture relatively painlessly and can enjoy the benefits of the platform. 相似文献
108.
Reverse nearest neighbors in large graphs 总被引:3,自引:0,他引:3
Man Lung Yiu Dimitris Papadias Nikos Mamoulis Yufei Tao 《Knowledge and Data Engineering, IEEE Transactions on》2006,18(4):540-553
A reverse nearest neighbor (RNN) query returns the data objects that have a query point as their nearest neighbor (NN). Although such queries have been studied quite extensively in Euclidean spaces, there is no previous work in the context of large graphs. In this paper, we provide a fundamental lemma, which can be used to prune the search space while traversing the graph in search for RNN. Based on it, we develop two RNN methods; an eager algorithm that attempts to prune network nodes as soon as they are visited and a lazy technique that prunes the search space when a data point is discovered. We study retrieval of an arbitrary number k of reverse nearest neighbors, investigate the benefits of materialization, cover several query types, and deal with cases where the queries and the data objects reside on nodes or edges of the graph. The proposed techniques are evaluated in various practical scenarios involving spatial maps, computer networks, and the DBLP coauthorship graph. 相似文献
109.
Man Lung Yiu Yufei Tao Nikos Mamoulis 《The VLDB Journal The International Journal on Very Large Data Bases》2008,17(3):379-400
Existing spatiotemporal indexes suffer from either large update cost or poor query performance, except for the B x -tree (the state-of-the-art), which consists of multiple B +-trees indexing the 1D values transformed from the (multi-dimensional) moving objects based on a space filling curve (Hilbert, in particular). This curve, however, does not consider object velocities, and as a result, query processing with a B x -tree retrieves a large number of false hits, which seriously compromises its efficiency. It is natural to wonder “can we obtain better performance by capturing also the velocity information, using a Hilbert curve of a higher dimensionality?”. This paper provides a positive answer by developing the B dual -tree, a novel spatiotemporal access method leveraging pure relational methodology. We show, with theoretical evidence, that the B dual -tree indeed outperforms the B x -tree in most circum- stances. Furthermore, our technique can effectively answer progressive spatiotemporal queries, which are poorly supported by B x -trees. 相似文献
110.
Nikos Antonopoulos Patrick Linke Antonis Kokossis 《Chemical Engineering Communications》2005,192(10):1258-1271
This article presents a GRID framework for distributed computations in the chemical process industries. We advocate a generic agent-based GRID environment in which chemical processes can be represented, simulated, and optimized as a set of autonomous, collaborative software agents. The framework features numerous advantages in terms of scalability, software reuse, security, and distributed resource discovery and utilization. It is a novel example of how advanced distributed techniques and paradigms can be elegantly applied in the area of chemical engineering to support distributed computations and discovery functions in chemical process engineering. A prototype implementation of the proposed framework for chemical process design is presented to illustrate the concepts. 相似文献