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181.
Grasso S Bellucci M Cocorullo G Della Corte FG Lodice M Rendina I 《Applied optics》2002,41(18):3601-3612
Rendina et al. recently proposed the original configuration of an electromagnetic power sensor for microwaves and millimeter waves that is based on an optically interrogated all-silicon chip [Electron. Lett. 35, 1748 (1999)]. Here we theoretically analyze and discuss in detail the performances of such a new class of nonperturbing and wideband probe in terms of sensitivity, resolution, intrinsic detectivity, linearity, and response time. Good agreement between theory and experiments is demonstrated. In particular, minimum resolutions of approximately 1 mW/cm2 are obtained at frequencies beyond 10 GHz. The dependence of response on the geometrical and electromagnetic parameters of the sensing element is analyzed, and on this basis the possibility of achieving optimized configurations is discussed. 相似文献
182.
183.
Spoto G 《Accounts of chemical research》2002,35(8):652-659
Chemistry plays a fundamental role in the preservation of our heritage. Artistic and archaeological materials deteriorate over time due to their interaction with the environment, and human intervention can trigger unexpected deterioration pathways. Previous intervention can also sometimes obscure information regarding the original techniques or the materials used to execute the artwork. Our studies of past intervention and attempts to conserve the lunette of the church of Santa Maria la Vetere in Militello Val di Catania (Italy) and Donatello's carved marble panels of the pulpit of the Duomo of Prato (Italy) are discussed as two examples of how chemistry can provide guidance for conservators and fill gaps in the known life of works of art. 相似文献
184.
Maurizio Bozzi Dominic Deslandes Paolo Arcioni Luca Perregrini Ke Wu Giuseppe Conciauro 《国际射频与微波计算机辅助工程杂志》2005,15(3):296-306
This article presents a substrate integrated waveguide, named the substrate‐integrated slab waveguide (SISW), which exhibits a wide operation bandwidth. It consists of an integrated rectangular waveguide filled with a periodically perforated dielectric medium. An efficient procedure has been developed for the calculation of the dispersion diagram of SISWs, based on the Floquet theorem, in conjunction with the segmentation technique and the boundary‐integral–resonant‐mode‐expansion (BI‐RME) method. Numerical and experimental results confirm the performance of these waveguides and the efficiency of the analysis method. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005. 相似文献
185.
Giuseppe Ferri Vincenzo Stornelli 《Analog Integrated Circuits and Signal Processing》2006,47(3):293-301
In this work we present an integrated interface for wide range resistive gas sensors able to heat the sensor resistance through
a constant power heater block at 0°C–350°C operating temperatures. The proposed temperature control system is formed by a
sensor heater (which fixes the sensor temperature at about 200°C), a R/f (or R/T) converter, which converts the resistive value into a period (or frequency), and can be able to reveal about 6 decades variation
(from 10 KΩ up to 10 GΩ), and a digital subsystem that control the whole systems loop. This interface allows high sensibility
and precision and performs good stability in temperature and power supply drift and low power characteristics so it can be
used also in portable applications. Test measurements, performed on the fabricated chip, have shown an excellent agreement
between theoretical expectations and simulation results.
Giuseppe Ferri is an associate professor in Electronics at the Department of Electrical Engineering of L’ Aquila University, Ital. In 1993
he has been a visiting researcher at SGS-Thomson Milano, working in bipolar low-voltage op-amp design. In 1994-95 he has been visiting researcher at KU Leuven working in low-voltage CMOS design in the group of Prof. Sansen. His research activity is actually centred on the analog
design of integrated circuits for portable applications (e.g., sensors and biomedicals) and circuit theory. He is co-author
of a book entitled “Low Voltage, Low Power CMOS Current Conveyors”, Kluwer ed. (2003) and four text-books in Italian on Analogue Microelectronics (2005, 2006). Moreover, he is author and
co-author of 74 papers on international and Italian journals and 123 talks at national and international conferences.
Vincenzo Stornelli was born in Avezzano (AQ), Italy, on May 31, 1980. He received the Electronics Engineering degree (cum laude) in July 2004.
In October 2004 he joined the Department of Electronic Engineering, University of L’Aquila, where he is actually involved
with problems concerning project and design of integrated circuits for RF and sensor applications, CAD modelling, characterization,
and design analysis of active microwave components, circuits, and subsystems. He regularly teaches courses of the European
Computer patent and has regular collaborations with national corporations such as Thales Italia 相似文献
186.
We address several problems concerning the geometry of the space of Hermitian operators on a finite-dimensional Hilbert space, in particular the geometry of the space of density states and canonical group actions on it. For quantum composite systems we discuss and give examples of entanglement measures. 相似文献
187.
188.
As group applications are becoming widespread, efficient network utilization becomes a growing concern. Multicast transmission represents a necessary lower network service for the wide diffusion of new multimedia network applications. Multicast transmission may use network resources more efficiently than multiple point-to-point messages; however, creating optimal multicast trees (Steiner Tree Problem in networks) is prohibitively expensive. This paper proposes a distributed algorithm for the heuristic solution of the Steiner Tree Problem, allowing the construction of effective distribution trees using a coordination protocol among the network nodes. Furthermore, we propose a novel distributed technique for dynamically updating the multicast tree. The approach proposed has been implemented and extensively tested both in simulation, and on experimental networks. Performance evaluation indicates that the distributed algorithm performs as well as the centralized version, providing good levels of convergence time and communication complexity. 相似文献
189.
Paola Carrara Daniela Fogli Giuseppe Fresta Piero Mussio 《Universal Access in the Information Society》2002,1(4):288-304
This paper proposes a new effective strategy for designing and implementing interactive systems overcoming culture, skill
and situation hurdles in Human-Computer Interaction (HCI). The strategy to identify and reduce these hurdles is developed
in the framework of a methodology based on a recently introduced model of HCI, and exploits the technological innovations
of XML (Extensible Markup Language). HCI is modelled as a cyclic process in which the user and the interactive system communicate
by materializing and interpreting a sequence of messages. The interaction process is formalized by specifying both the physical
message appearance and the computational aspect of the interaction. This formalization allows the adoption of notation traditionally
adopted by users in their workplaces as the starting point of the interactive system design. In this way, the human–system
interaction language takes into account the users’ culture. Moreover, the methodology permits user representatives to build
a hierarchy of systems progressively adapted to users’ situations, skills and habits, according to the work organization in
the domain considered. The strategy is proved to be effective by describing how to implement it using BANCO (Browsing Adaptive
Network for Changing user Operativity), a feasibility prototype based on XML, which allows the hierarchy implementation and
system adaptations. Several examples from an environmental case under study are used throughout the paper to illustrate the
methodology and the effectiveness of the technology adopted.
Published online: 4 June 2002 相似文献
190.
The paper describes the application of parallel techniques to amultibody multidisciplinary formulation. The problem is stated interms of a system of nonlinear Differential-Algebraic Equations(DAE). The parallel solution is obtained using a sub-structuringdomain decomposition method, that is able to exploit thecharacteristic quasi-monodimensional topology that multibodymodels usually present. The presence of explicit constraints inform of algebraic equations requires particular care in thetreatment of the related unknowns, to avoid local singularityproblems. The code has been successfully tested on differentcomputer architectures. Special attention has been dedicated toproduce a code that will efficiently work on a cluster of PCs.Results of three test problems, regarding the simulation of anonlinear beam bending and of complex aeroservomechanical systemsas an helicopter rotor and a tiltrotor aircraft, are presented. 相似文献