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581.
Dattoli G. Galli M. Giannessi L. Ottaviani P.L. Torre A. 《Quantum Electronics, IEEE Journal of》1994,30(5):1283-1288
In this note we present an analysis of FEL saturation mechanisms, with particular attention to the case of optical-klystron (O.K.) devices operating with low energy e-beam in the single-passage configuration. We discuss the range of validity of already introduced FEL gain versus intensity saturation formulae and show that O.K. FEL saturation occurs in two distinct steps. In the first, the dispersive section is “turned-off,” in the second, saturation in the conventional sense is reached 相似文献
582.
Control algorithms of networked multiagent systems are generally computed distributively without having a centralised entity monitoring the activity of agents; and therefore, unforeseen adverse conditions such as uncertainties or attacks to the communication network and/or failure of agent-wise components can easily result in system instability and prohibit the accomplishment of system-level objectives. In this paper, we study resilient coordination of networked multiagent systems in the presence of misbehaving agents, i.e. agents that are subject to exogenous disturbances that represent a class of adverse conditions. In particular, a distributed adaptive control architecture is presented for directed and time-varying graph topologies to retrieve a desired networked multiagent system behaviour. Apart from the existing relevant literature that make specific assumptions on the graph topology and/or the fraction of misbehaving agents, we show that the considered class of adverse conditions can be mitigated by the proposed adaptive control approach that utilises a local state emulator – even if all agents are misbehaving. Illustrative numerical examples are provided to demonstrate the theoretical findings. 相似文献
583.
L Gao Q Liu J. S Hong H Miyamoto S. D De La Torre A Kakitsuji K Liddell D. P Thompson 《Journal of Materials Science》1998,33(6):1399-1403
Co-precipitation methods have been used to produce 20 mol% Al2O3–80 mol% ZrO2 mixed oxides, from aqueous solutions of zirconium oxychloride and aluminium chloride, followed by precipitation with ammonia. The resulting gel was calcined at increasing temperatures, and X-ray diffraction confirmed that the structure remained amorphous up to 750°C and then crystallized as a single-phase cubic zirconia solid solution, but with a reduced unit-cell dimension. At higher temperatures, the unit-cell dimension increased and, above 950°C, this phase started to transform to a tetragonal zirconia (t-ZrO2) phase, again of reduced cell dimensions compared with t-ZrO2, with simultaneous appearance of small amounts of -Al2O3. Above 1100°C, the tetragonal phase transformed to monoclinic zirconia on cooling, and the amount of -Al2O3 increased. Above 1200°C, the -Al2O3 transformed to the stable -Al2O3. These results confirm that aluminium acts as a stabilizing cation for zirconia up to temperatures of about 1100°C. © 1998 Chapman & Hall 相似文献
584.
Tarek R. Besold Artur d’Avila Garcez Keith Stenning Leendert van der Torre Michiel van Lambalgen 《Minds and Machines》2017,27(1):37-77
This article aims to achieve two goals: to show that probability is not the only way of dealing with uncertainty (and even more, that there are kinds of uncertainty which are for principled reasons not addressable with probabilistic means); and to provide evidence that logic-based methods can well support reasoning with uncertainty. For the latter claim, two paradigmatic examples are presented: logic programming with Kleene semantics for modelling reasoning from information in a discourse, to an interpretation of the state of affairs of the intended model, and a neural-symbolic implementation of input/output logic for dealing with uncertainty in dynamic normative contexts. 相似文献
585.
Camilla Della Torre Ilaria Corsi Maria Maddalena Dinardo Luigi Alcaro Angelo Tursi Antonio Frigeri 《The Science of the total environment》2010,408(9):2136-2145
The aim of the present study was to evaluate the environmental threat to benthic species from chemical weapons dumped in the southern Adriatic Sea. An ecotoxicological approach using chemical analysis and biological responses was applied, in two sentinel species: the Blackbelly rosefish Helicolenus dactylopterus and European conger Conger conger. Specimen were collected in a stretch of sea, where had been dumped war materials and from a reference site free of ordnance. Residues of yperite, Hg and As were measured in fish fillets. Skin, liver, kidney and spleen were examined for histopathological and macroscopical lesions. Liver detoxifying capacities (EROD and UDPGT) and genotoxicity (comet assay) were also investigated. As and Hg levels were three-four times higher than those from the reference site in both species (p < 0.001). Both species captured in dumping site showed clear signs of chronic illness according to the health assessment index (HAI). Deep ulcers and nodules were observed on skin and external organs. Histological lesions such as periportal and bile duct fibrosis, pericholangitis, steatosis, granuloma and elevated splenic MMCs were detected in liver and spleen. Significantly higher EROD activities were also found in both species from dumping site (p < 0.01). Comet assay revealed genotoxicty in gills of C. conger from dumping site, indicating uptake of chemical warfare agents through fish gills. European conger was found to be a more sensitive bioindicator of this type of contamination than the Blackbelly rosefish. 相似文献
586.
Stefano Della Torre 《建筑学研究前沿(英文版)》2021,10(3):108-116
This paper tells us a complex story on the historic evolution of preventive conser-vation of architectural heritage in Italy.Firstly,it introduces Cesare Brandi's Theory of Resto-ration,pointing out the peculiar sense of the word Restoration in Brandi's system other than the common sense in the international discourse,the limits of Brandi's theory to architectural conservation and his prophecy on preventive restoration.Then it talks about the different framework and practices of preventive conservation in the field of built heritage compared to the museum sector,the milestone of Giovanni Urbani's pilot project on programmed conser-vation and the leading role of the Risk Map of Cultural Heritage.Finally,based on the discus-sions of the durable change in the architectural conservation field after the Venice Charter,including the teaching in Milan School,the debate and re-definition of architectural conserva-tion and the advance definitions of conservation,prevention,maintenance and restoration in the 2004 National Code of Cultural Heritage and Landscape,it gives us an agenda for future trends of planned conservation with aims to conserve the material authenticity and promote the co-evolutional strategy. 相似文献
587.
This paper documents a practical numerical method of evaluating damping of slow oscillations in computer simulations of large power systems. This technique has been tested and improved over the last two years. The damping coefficients can assist in evaluation of acceptable transfer limitations. The proposed method also provides a means to evaluate the sensitivity of various transfer path loadings and transmission and generation facility contingencies on system damping. 相似文献
588.
Della Torre E. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1990,78(6):1017-1026
Quasi-static magnetic processes such as those found in magnetic recording are examined. The hysteresis in medium-hard magnetic materials of the type used in recording media and the magnetizability of soft magnetic materials such as those used in recording heads are discussed. Two general modeling techniques are used to describe these processes: physical modeling and phenomenological modeling. In physical modeling, the basic processes involved are simulated in order to be able to describe the basic magnetizing modes. In phenomenological models, the gross behavior of the material is described mathematically by Preisach-type models in order to couple the material properties to Maxwell's equations so as to obtain solutions of field problems. The latter models are computationally more efficient than the former, but they do not give any insight into the physical principles involved 相似文献
589.
Park J.-S. Neugroschel A. de la Torre V. Zdebel P.J. 《Electron Devices, IEEE Transactions on》1991,38(2):365-372
New DC methods to measure the collector resistance R C and emitter resistance R E are presented. These methods are based on monitoring the substrate current of the parasitic vertical p-n-p transistor linked with the n-p-n intrinsic transistor. The p-n-p transistor is operated with either the bottom substrate-collector or the top base-collector p-n junction forward-biased. This allows for a separation of the various components of R C. R E is obtained from the measured lateral portion of R C and the collector-emitter saturation voltage. Examples of measurements on advanced self-aligned transistors with polysilicon contacts are shown. The results show a very strong dependence of R C on the base-emitter and base-collector voltages of the n-p-n transistor. The bias dependence of R C is due to the conductivity modulation of the epitaxial collector. From the measured emitter resistance R E a value for the specific contact resistance for the polysilicon emitter contact of ρc≅50 Ω-μm2 is obtained 相似文献
590.