86,953 research outputs found
Multiphysics Modeling of the Electromagnetic-Coherent Transport Phenomena in RF in Nanodevices
No full textRadio-Frequency Nanoelectronics: a new Paradigm in Electronic Systems Design
No full textOwing to the new qualitative and quantitative improvements that nanotechnology allows, nanoelectronics has the potential to introduce a paradigm shift in electronic systems design similar to that of the transition from vacuum tubes to semiconductor technology. Since many nano-scale devices and materials exhibit their most interesting properties at radiofrequencies (RF), nanoelectronics represent an enormous and yet largely undiscovered opportunity for the microwave engineering community, which can utilize its established body of modelling, design and measurement techniques with the aim to bridge the gap between nano-science and a new generation of extremely integrated devices, circuits and systems, for a broad range of applications and operating frequencies covering the radiofrequency (RF) spectrum, through the microwave region, and up to the optical region. In this contribution, examples of recent achievements in new nanotechnology-based radio-frequency devices and systems are presented. This is done, in particular, by focusing the areas of carbon-based and terahertz nanoelectronic
Carbon based ballistic RF electronics
No full textIn the past decade the progresses in
nanofabrication, modeling (from atomistic to mesoscopic scales),
and advances in nanocharacterisation have triggered an entirely
new class of nanodevices. Owing to their superior electrical and
mechanical performances, carbon based meterials such as
graphene and carbon nanotubes (CNTs) have played a central
role in these groundbreaking developments. Among the many,
one of the most relevant feature of these materials is the
capability to allow room temperature ballistic transport.
This feature enables yet more compact and yet more efficient RF
circuits, endowed of higher current density, higher on/off ratio
and higher fmax/ft ratios.
In this talk the activities ongoing in this area will be outlined
through an European perspective by focusing on some
emblematic examples of graphene based ballistic devices
Graphene-based wireless communications systems: Analysis of the EM-quantum transport of coupled nano-patch antennas
No full textThe possibility of using graphene-based antennas is a core point in the development of high speed, multifunctional new wireless architecture, leading to a new generation of smart nano-systems for wireless communications, and wireless power transfer. In this work, we present a first analysis of the electromagnetic-quantum transport among the different graphene-based antennas. The former analysis is a building block for the design of a complete smart nanosystems for wireless communications at micro and mm-wave frequencie
Advanced modeling of graphene nanodevices: Metal-carbon transition and patch antennas
No full textWe report on multiphysics full-wave techniques in the frequency (energy)-domain and the time-domain, aimed at the investigation of the combined electromagnetic-coherent transport problem in carbon based nano-structured materials and devices, e.g. graphene nanoribbons. The frequency-domain approach is introduced in order to describe a Poisson/Schroedinger system in a quasi static framework. An example about the self-consistent solution of laterally coupled graphene nanoribbons is shown. The time-domain approach deals with the solution of the combined Maxwell/Schroedinger system of equations. We deal with i) the very challenging problem of he analysis of charge injection from metal to a contacted graphene nanoribbon (GNR); ii) a first prototype of graphene-based patch antenna
Synthesis and biological evaluation of combretastatin analogs as cell cycle inhibitors of the G1 to S transition in Saccharomyces cerevisiae
No full textA series of Z and E combretastatin A-4 analogs bearing different substituents (OH, F, NO2, NH2, B(OH)2) in the 3′ position were synthesized. These derivatives and Z and E combretastatin A-1 were analysed by monitoring their ability to inhibit cell growth in Saccharomyces cerevisiae. Combretastatin A-1 (2a), A-4 (2b) and compound 2c were found to inhibit yeast growth. Moreover, combretatstatin A-4 (2b) and compound 2c induced a G1 arrest by affecting the synthesis of Clb5 protein, the principal S-phase cyclin. The G1 arrest is coincident with the activation of the stress activated kinase Snf
Preferential exchange: strengthening connections in complex networks
No full textMany social, technological, and biological interactions involve network relationships whose outcome intimately depends on the structure of the network and on the strengths of the connections. Yet, although much information is now available concerning the structure of many networks, the strengths are more difficult to measure. Here we show that, for one particular social network, notably the e-mail network, a suitable measure of the strength of the connections can be available. We also propose a simple mechanism, based on positive feedback and reciprocity, that can explain the observed behavior and that hints toward specific dynamics of formation and reinforcement of network connections. Network data from contexts different from social sciences indicate that power-law, and generally broad, distributions of the connection strength are ubiquitous, and the proposed mechanism has a wide range of applicability
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