Vibrational spectra of functionalized fullerenes containing amide

The set of three new hydrogen bonding functionalized fullerenes containing amide (PCB-t-BA, PCB-n-BA, and MPCB-t-BA) was investigated using the infrared absorption and Raman scattering spectroscopies. Additionally, the quantum chemical calculations of the equilibrium geometry and normal mode vibrations of the molecules were performed. Role of hydrogen bonds (HB) in the investigated samples was under our particular attention. Bifurcated HB was suggested.     

Coatings against corrosion and microbial adhesion

A systematic study on anti‐corrosion and anti‐fouling effect of hydrophobic Langmuir–Blodgett and self‐assembled molecular layers deposited on metal surfaces, as well as anti‐microbial adhesion properties of coatings with biocide is presented. Both types of efficiencies produced by LB films are enhanced by Fe³⁺ ions built in the molecular film. The quaternary ammonium type biocide embedded into the cross‐linked gelatin decreased significantly the microbial adhesion, the biofilm formation.     

Cost‐Efficient Virtual Optical Network Embedding for Manageable Inter‐Data‐Center Connectivity

Network virtualization opens the door to novel infrastructure services offering connectivity and node manageability. In this letter, we focus on the cost‐efficient embedding of on‐demand virtual optical network requests for interconnecting geographically distributed data centers. We present a mixed integer linear programming formulation that introduces flexibility in the virtual‐physical node mapping to optimize the usage of the underlying physical resources. Illustrative results show that flexibility in the node mapping can reduce the number of add‐drop ports required to serve the offered demands by 40%.     

Artifact removal in magnetoencephalogram background activity with independent component analysis

The aim of this study was to assess whether independent component analysis (ICA) could be valuable to remove power line noise, cardiac, and ocular artifacts from magnetoencephalogram (MEG) background activity. The MEGs were recorded from 11 subjects with a 148-channel whole-head magnetometer. We used a statistical criterion to estimate the number of independent components. Then, a robust ICA algorithm decomposed the MEG epochs and several methods were applied to detect those artifacts. The whole process had been previously tested on synthetic data. We found that the line noise components could be easily detected by their frequency spectrum. In addition, the ocular artifacts could be identified by their frequency characteristics and scalp topography. Moreover, the cardiac artifact was better recognized by its skewness value than by its kurtosis one. Finally, the MEG signals were compared before and after artifact rejection to evaluate our method.     

CMOS harmonic upconverter with power management of $$2{\bf nd}$$ harmonic for wideband short-range communications

The design and simulation of a 2nd harmonic based upconverter is introduced. With the proposed upconverter, it is possible to reach a good noise figure with power and area reduction. The design of the circuit was made with the UMC \(0.18\,\upmu \hbox {m}\) Mixed Mode/RF CMOS technology. However, the design methodology can be extended to a different CMOS process. According to the performance exhibited by the purposed mixer, it may be useful in wideband short-range communication technologies, such as certified wireless USB.     

Effect of interesterified fat mixtures on certain lipid indices in experimental fat metabolism disturbance

Groups of adult Wistar male and female rats were fed isoenergetically for a three and a six weeks period either with synthetic lipogenic diet containing 5% and 20% fat mixtures (in which sunflower oil and lard were blended according to the ratio of 35:65) or with the same synthetic diet containing the mixture of sunflower oil and interesterified lard in a similar ratio. A control group received a normal diet for 6 weeks, whereas one of the experimental groups (fed with the 20% fat mixture in the lipogenic diet for 6 weeks) was given the normal diet for an additional two weeks period. After the feeding periods had been completed serum HDL-C levels and the total lipid, triglyceride, total cholesterol, free fatty acid levels were determined in serum and liver. The distribution of fatty acids in liver and heart muscle was also evaluated. In comparison to the control values it has been found: 1. Consumption of the lipogenic diet which is known to increase the serum total lipid and total cholesterol content induced in male rats a smaller augmentation in these indices when consuming the 20% fat mixture with a P/S ratio approaching the ideal 1 values, than in case of a 5% fat mixture consumption. In case of female rats, considerable increases of the serum values, could be observed at both fat consumption levels. The serum triglyceride and HDL-C contents decreased for all experimental groups. 2. The total lipid and triglyceride content of the liver increased in a high degree, the fatty liver syndrome was developed--more rapidly in males than in females. The total lipid, triglyceride and total cholesterol contents of the liver of male rats exceeded those of females by 15-30%. 3. The interesterification of the lard component of fat mixture resulted in lipid indices similar to those without interesterification, or in certain cases, they were found to be even slightly more favourable, i.e. the biological effect of the technological change proved to be adequate. 4. After a two weeks regeneration period the serum values of the male rats approached closer the normal control values than those of the females which were decreasing from a very high level but the degree of decrease was greater for them than for the male rats. The lipid content of the liver showed similar values.(ABSTRACT TRUNCATED AT 400 WORDS)     

Centralized and decentralized stochastic routing models in telecommunication networks

With the advent of non-hierarchical routing in circuit-switched telecommunication networks, on-line routing policies have been developed with the objective of optimizing some measure of gain or performance. These policies are decentralized. However, traditional planning models are centralized models. We present a decentralized routing model to be used in network planning. We compare it theoretically and empirically with a centralized multicommodity flow model previously presented. The two models are solved by the same type of algorithm, a convex simplex implementation, adapted differently according to the model. Comparative results between planning models reproducing the two policies are discussed.     

Numerical Analysis of Current–Voltage Characteristics of LWIR nBn and p-on-n HgCdTe Photodetectors

We performed numerical analysis of the current–voltage characteristics of long-wavelength infrared unipolar HgCdTe nBn photodetectors and compared those results with those of conventional p-on-n HgCdTe photodiodes. A computer program was applied to explain in detail the impact of the charge carrier generation and recombination processes on current densities. In our model the carrier diffusion, thermal generation–recombination, band-to-band tunneling, trap-assisted tunneling (via states located at mercury vacancies as well as dislocation cores), and impact ionization are included as potential limiting mechanisms. To validate the model, we compared the theoretical predictions with experimental data of high-quality p-on-n photodiodes published in the literature.     

Image reconstruction using interval simulated annealing in electrical impedance tomography

Electrical impedance tomography (EIT) is an imaging technique that attempts to reconstruct the impedance distribution inside an object from the impedance between electrodes placed on the object surface. The EIT reconstruction problem can be approached as a nonlinear nonconvex optimization problem in which one tries to maximize the matching between a simulated impedance problem and the observed data. This nonlinear optimization problem is often ill-posed, and not very suited to methods that evaluate derivatives of the objective function. It may be approached by simulated annealing (SA), but at a large computational cost due to the expensive evaluation process of the objective function, which involves a full simulation of the impedance problem at each iteration. A variation of SA is proposed in which the objective function is evaluated only partially, while ensuring boundaries on the behavior of the modified algorithm.     

ADC Non-Linearity Low-Cost Test Through a Simplified Double-Histogram Method

This paper introduces a method to reduce the requirements of the test sources for evaluating the non-linearity characteristics of Analogue-to-Digital converters. The method is based on a non-interleaved Double-Histogram test independent of the test signal waveform. It has been validated by simulation results in a 16-bit pipeline A/D converter and by an experimental example using the AD6644 commercial converter.