One Dimensional Inverse Dielectric Profiling of Embedded Slabs by a Quadratic Approximation

In this paper the inverse problem of the determination of the dielectric profile of a slab embedded into a homogeneous half space starting from the knowledge of the scattered field for different illumination angles is considered. A comparison between the features of a linear and a quadratic distorted approximation of the scattering problem is carried out, in order to determine the kind of profiles that can be reconstructed. In particular, the investigation of the direct problem reveals that, under the linear approximation, only a limited number of Fourier harmonics of the profile give contribution to the scattered field. The use of the quadratic approximation allows to change the number and order of the harmonic that can be imaged. The dependence of the results on the dielectric permittivity of the host medium is also highlighted. Numerical examples support the theoretical considerations.     

Joint near-lossless compression and watermarking of still images for authentication and tamper localization

A system is presented to jointly achieve image watermarking and compression. The watermark is a fragile one being intended for authentication purposes. The watermarked and compressed images are fully compliant with the JPEG-LS standard, the only price to pay being a slight reduction of compression efficiency and an additional distortion that can be anyway tuned to grant a maximum preset error. Watermark detection is possible both in the compressed and in the pixel domain, thus increasing the flexibility and usability of the system. The system is expressly designed to be used in remote sensing and telemedicine applications, hence we designed it in such a way that the maximum compression and watermarking error can be strictly controlled (near-lossless compression and watermarking). Experimental results show the ability of the system to detect tampering and to limit the peak error between the original and the processed images.     

White Electroluminescence by Supramolecular Control of Energy Transfer in Blends of Organic‐Soluble Encapsulated Polyfluorenes

Here, it is demonstrated that energy transfer in a blend of semiconducting polymers can be strongly reduced by non‐covalent encapsulation of one constituent, ensured by threading of the conjugated strands into functionalized cyclodextrins. Such macrocycles control the minimum intermolecular distance of chromophores with similar alignment, at the nanoscale, and therefore the relevant energy transfer rates, thus enabling fabrication of white‐light‐emitting diodes (CIE coordinates: x = 0.282, y = 0.336). In particular, white electroluminescence in a binary blend of a blue‐emitting, organic‐soluble rotaxane based on a polyfluorene derivative and the green‐emitting poly(9,9‐dioctylfluorene‐alt‐benzothiadiazole ( F8BT ) is achieved. Morphological and structural analyses by atomic force microscopy, fluorescence mapping, µ‐Raman, and fluorescence lifetime microscopy are used to complement optical and electroluminescence characterization, and to enable a deeper insight into the properties of the novel blend.     

Capacitance DNA bio-chips improved by new probe immobilization strategies

Label-free DNA detection plays a crucial role in developing point-of-care biochips. Capacitance detection is a promising technology for label-free detection. However, data published in literature often show evident time drift, large standard deviation, scattered data points, and poor reproducibility. To address these problems, mercapto-hexanol or similar alkanethiols are usually considered as blocking agents. The aim of the present paper is to investigate new blocking agents to further improve DNA probe surfaces. Data from AFM, SPR, florescence microscopy, and capacitance measurements are used to investigate new lipoate and ethylene-glycol molecules. The new surfaces offer further improvements in terms of diminished detection errors. Film structures are investigated at the nano-scale to justify the detection improvements in terms of probe surface quality. This study demonstrates the superiority of lipoate and ethylene-glycol molecules as blocking candidates when immobilizing molecular probes onto spot surfaces in label-free DNA biochip.     

A polyfluoroalkyl imidazolium ionic liquid as iodide ion source in dye sensitized solar cells

We report on the use of a fluorinated imidazolium ionic liquid as a source of iodide ions in solvent-based electrolytes for DSSCs. Efficient dye regeneration and fast charge transport in the fluorinated electrolyte result in an overall improvement of the device performances compared to conventional hydrogenated ionic liquids.     

Transport layer enhancements on a satellite‐based mobile broadband system for high‐speed trains

The great diffusion of wireless portable and handheld devices, along with the growing availability of applications on the Internet, led to a significant increase in the demand of access. Users require to continue business or private activities when moving, with performance at least comparable with that experienced over fixed networks. A very interesting scenario encompasses broadband and uninterrupted access over high‐speed trains. Developments of new telecommunication standards as well as innovative network architectures give the potential to fully match the aforementioned requirements. Nevertheless, there is a significant number of issues, especially related to system integration, mobility management, and propagation channel conditions, that need a careful analysis with the aim to support the design of real systems. This paper deals with this challenging scenario proposing a satellite‐based architecture in which DVB‐S2 and DVB‐RCS standards, MIPv6 at layer 3 (for handover management), and an enhanced TCP version at layer 4, named TCP Noordwijk, allow to achieve good performance. An NS‐2 enhanced simulator has supported the whole analysis. Results show the effectiveness of the proposed scheme against different modulation and coding configurations and compared with a selected set of TCP‐enhanced versions. Copyright © 2012 John Wiley & Sons, Ltd.     

Reduced Impact of Induced Gate Noise on Inductively Degenerated LNAs in Deep Submicron CMOS Technologies

Designers of radio-frequency inductively-degenerated CMOS low-noise-amplifiers have usually not followed the guidelines for achieving minimum noise figure. Nonetheless, state-of-the-art implementations display noise figure values very close to the theoretical minimum. In this paper, we point out that this is due to the effect of the parasitic overlap capacitances in the MOS device. In particular, we show that overlap capacitances lead to a significant induced-gate-noise reduction, especially when deep sub-micron CMOS processes are used.Paolo Rossi was born in Milan, Italy, in 1975. He received the Laurea degree (summa cum laude) in electrical engineering from the University of Pavia, Pavia, Italy, in 2000, where he is currently working toward the Ph.D. degree. His research interests are in the field of analog integrated circuits for wireless transceivers in CMOS and BiCMOS technology, with particular focus on the analysis and design of LNA and mixer for multi-standard applications.Francesco Svelto received the Laurea and Ph.D. degrees in electrical engineering from the University of Pavia, Pavia, Italy, in 1991 and 1995, respectively. From 1996 to 1997, he held a grant from STMicroelectronics to design CMOS RF circuits. In 1997, he was appointed Assistant Professor at the University of Bergamo, Italy, and in 2000, he joined the University of Pavia, where he is an Associate Professor. His current research interests are in the field of RF design and high-frequency integrated circuits for telecommunications. Dr. Svelto has been a member of the technical program committee of the IEEE Custom Integrated Circuits Conference since 2000 and the Bipolar/BiCMOS Circuits and Technology Meeting (BCTM) since 2003, and the European Solid State Circuits Conference in 2002. He served as Guest Editor of the March 2003 special issue of the IEEE Journal of Solid-State Circuits, of which he is currently an Associate Editor.Andrea Mazzanti was born in Modena (Italy) in 1976. He received the Laurea degree (summa cum Laude) in Electrical Engineering from the University of Modena and Reggio Emilia, Modena, Italy in 2001. Since 2001 he is pursuing his PhD in Electrical Engineering at University of Modena and Reggio Emilia, Italy. His major research interest are modelling of microwave semiconductor devices and design of CMOS RF integrated circuits, with particular focus on low noise oscillators and analog frequency dividers. During the summer of 2003 he was with Agere Systems, Allentown, PA as an internship student, working on the design of an highly integrated CMOS FM transmitter.Pietro Andreani received the M.S.E.E. from the University of Pisa, Italy, in 1988. He joined the Dept. of Applied Electronics, Lund University, Sweden, in 1990, where he contributed to the development of software tools for digital ASIC design. After working at the Dept. of Applied Electronics, University of Pisa, as a CMOS IC designer during 1994, he rejoined the Dept. of Applied Electronics in Lund as an Associate Professor, where he was responsible for the analog IC course package between 1995 and 2001, and where he received the Ph.D. degree in 1999. He is currently a Professor at the Center for Physical Electronics, ØrstedDTU, Technical University of Denmark, Kgs. Lyngby, Denmark, with analog/RF CMOS IC design as main research field.