Localized Ligand Induced Electroless Plating (LIEP) Process for the Fabrication of Copper Patterns Onto Flexible Polymer Substrates

The “ligand induced electroless plating (LIEP) process” is a simple process to obtain localized metal plating onto flexible polymers such as poly(ethylene terephtalate) and polyvinylidene fluoride sheets. This generic and cost‐effective process, efficient on any common polymer surface, is based on the covalent grafting by the GraftFast process of a thin chelating polymer film, such as poly(acrylic acid), which can complex copper ions. The entrapped copper ions are then chemically reduced in situ and the resulting Cu⁰ species act as a seed layer for the electroless copper growth which, thus, starts inside the host polymer. The present work focuses on the application of the LIEP process to the patterning of localized metallic tracks via two simple lithographic methods. The first is based on a standard photolithography process using a positive photoresist masking to prevent the covalent grafting of PAA in designated areas of the polymer substrate. In the second, the patterning is performed by direct printing of the mask with a commercial laser printer. In both cases, the mask was lifted off before the copper electroless plating step, which provides ecological benefits, since only the amount of copper necessary for the metallic patterning is used.     

Multiplexer model for RTL satisfiability using MILP

New approaches to the satisfiability problem (SAT) for register transfer level (RTL) designs combine arithmetic blocks with Boolean logic to form a mixed integer linear program (MILP). Two-to-one multiplexers with word-level inputs can be decomposed to logic gates, but it is more efficient to describe them in MILP constraints as arithmetic operators. Larger multiplexers are built using a multilevel selection tree. However, such an approach should be improved to optimise the overall efficiency in solving the SAT problem. Proposed is a new MILP model for multiplexers. Experimental results indicate a 50% decrease in the number of constraints and a reduction in MILP complexity from /spl Omega/(N/sup 2.4/) to /spl Omega/(N/sup 1.7/), measured in CPU time.     

Connectivity Based k-Hop Clustering in Wireless Networks

In this paper we describe several new clustering algorithms for nodes in a mobile ad hoc network. The main contribution is to generalize the cluster definition and formation algorithm so that a cluster contains all nodes that are at distance at most k hops from the clusterhead. We also describe algorithms for modifying cluster structure in the presence of topological changes. We also proposed an unified framework for most existing and new clustering algorithm where a properly defined weight at each node is the only difference in otherwise the same algorithm. This paper studied node connectivity and node ID as two particular weights, for k=1 and k=2. Finally, we propose a framework for generating random unit graphs with obstacles.     

Brain-computer interface in multimedia communication

This article raises various issues in the design of an efficient BCI system in multimedia applications. The main focus is on one specific modality, namely an electroencephalography (EEG)-based BCI. In doing so, we provide an overview of the most recent progress achieved in this field, with an emphasis on signal processing aspects.     

Design optimization and characterization of high-gain GaInP/GaAsHBT distributed amplifiers for high-bit-rate telecommunication

The design methodology, processing technology, and characterization of high-gain GaInP/GaAs heterojunction-bipolar-transistor-based distributed amplifiers are described in this paper. Distributed amplifiers with different active cells and number of stages have been compared for high-gain (>12 dB) and high-bandwidth (>25 GHz) performance. Based on the results, a three-stage attenuation-compensated distributed amplifier with a flat gain (S₂₁) of 12.7 dB over a bandwidth of 27.5 GHz was successfully fabricated and tested. Eye-diagram tests at 10 Gb/s show very open eye characteristics with no signal skewing. The amplifier achieves a minimum noise figure of 4 dB at 3 GHz and a sensitivity of -25 dBm for 10-Gb/s nonreturn-to-zero 2¹⁵-1 pseudorandom bit sequence with a bit error rate of 10^-9     

In vitro and in vivo determinations of sun protection factors of sunscreen lotions with octylmethoxycinnamate

The aim of this work was to evaluate the correlation between in vitro and in vivo determinations of sun protection factors (SPF) of sunscreen lotions containing the synthetic sunscreen octyl methoxycinnamate. Three sunscreen lotions containing either 2, 4.5 or 7.5% octyl methoxycinnamate were prepared. The in vitro SPFs of these sunscreen lotions were determined according to the spectrophotometric method of Mansur et al. The in vivo SPF values were determined according to the Food and Drug Administration (FDA) method. The results indicate that there was a good correlation between the in vitro and in vivo determinations for the sunscreen lotions examined.     

Cholesterol content and fatty acid composition of rhea meat

The influence of species and muscle on the intramuscular fat content, cholesterol content and fatty acid composition of Greater and Lesser Rhea meat were evaluated. Muscle has no influence (P>0.05) on any of these characteristics. Neither intramuscular fat (1.23%) nor cholesterol content (57 mg/100 g) differed (P>0.05) between species. Despite differences (P<0.05) in the percentage of individual fatty acids, total saturated fatty acids (33.1%) did not differ (P>0.05) between species, while total monounsaturated fatty acids (26.8 vs 32.2%) was lower (P<0.05) and total polyunsaturated fatty acids (39.7 vs 33.6%) higher (P<0.05) for Greater than Lesser Rhea.     

Particle-Swarm Optimization in Antenna Design: Optimization of Log-Periodic Dipole Arrays

This paper presents a short tutorial and overview of optimization algorithms based on particle-swarm schemes, and their application to solving electromagnetic problems. As a practical example, a particle-swarm optimization (PSO) tool has been applied in conjunction with the Numerical Electromagnetics Code (NEC) to get the design curves of optimized log-periodic dipole arrays (LPDAs). The graphs show the performance of several radiation parameters (directive gain, front-to-back ratio, bandwidth, SWR, and half-power beamwidth in the E and H planes) as a function of typical design parameters of log-periodic dipole arrays (geometrical parameters and characteristics of the feed). Examples of optimized antennas are given, and their performance is compared to that of standard log-periodic dipole arrays.     

Nanoparticle ordering by dewetting of Co on SiO2

Most metals on SiO₂ have a finite contact angle and are therefore subject to dewetting during thermal processing. The resulting dewetting morphology is determined primarily by nucleation and growth or instabilities. The dewetting mechanism implies a disordered spatial arrangement for homogeneous nucleation, but an ordered one for instabilities such as spinodal decomposition. Here, we show that the morphology of laser-melted ultrathin Co film (4-nm thick) can be attributed to dewetting via an instability. Dewetting leads to breakup of the continuous Co film into nanoparticles with a monomodal size distribution with an average particle diameter of 75 nm±23 nm. These nanoparticles have short-range order (SRO) of 130 nm in their separation. This result has important implications for nanomanufacturing with a robust spacing or size selection of nanoparticles in addition to spatial ordering.     

Diagnosis of learner dropout based on learning styles for online distance learning

The amount of data generated by computer systems in Online Distance Learning (ODL) contains rich information. One example of this information we define as the Learner Learning Trail (LLT), which is the sequence of interactions between the students and the virtual environment. Another example is the Learner Learning Style (LLS), which is associated with the student behavior and choices during the learning process. This information can be used to identify learner behavior and learning style. We perceived, after the study of related literature, that the research field of learner diagnosis for ODL does not apply the conjoint use of LLT and LLS. In this article, we propose a model capable of integrating data generated from the behavior of students in ODL with cognitive aspects of them, such as their Learning Styles, by crossing LLT with LLS. We also propose the CPAD method (Collect, Preprocessing, Analysis, Diagnosis), which is implemented by collecting the raw data regarding learning activities, preprocessing the data into structured time sequences, analyzing the sequences regarding the learning styles and using this analysis to diagnose the learner behavior. We selected the dropout to investigate, once the dropout rate in ODL is a real problem in universities around the world. In addition, the dropout is a student decision which can be associated with previous students behaviors. We performed a study with 202 learners to evaluate if learning styles are capable of explaining aspects of the student behavior. The results suggest that Sequential/Global learning style dimension is more capable of explaining the dropout than the other dimensions. Also, we performed four classification experiments to verify how the dimensions of Felder-Silverman Learning Style Model influence the learner diagnosis. We perceived that the Sequential/Global dimension could provide a higher accuracy average with lower variation independently of the diagnosis technique.