The Critical Role of the Underlayer Material and Thickness in Growing Vertically Aligned Carbon Nanotubes and Nanofibers on Metallic Substrates by Chemical Vapor Deposition

Vertically aligned carbon nanotubes and nanofibers are grown on metallic Ta and Pd underlayers at temperatures below 500 °C. Controlling the size of the grains of the underlayer film is critical because this leads to a more uniform distribution of catalyst dots, which in turn results in vertical alignment of the carbon nanostructures. Rapid and limited heating and appropriate materials selection can also be used to limit catalyst/underlayer reactions that hinder or suppress carbon nanostructure growth or that lead to entangled growth. Control of catalyst reactivity with metallic underlayers is significant because growth on conductive substrates is notoriously difficult, but needed for many applications such as the use of carbon nanostructures in microelectronic circuits.     

Electricity consumption and CO2 capture potential in Spain

In this paper, different electricity demand scenarios for Spain are presented. Population, income per capita, energy intensity and the contribution of electricity to the total energy demand have been taken into account in the calculations. Technological role of different generation technologies, i.e. coal, nuclear, renewable, combined cycle (CC), combined heat and power (CHP) and carbon capture and storage (CCS), are examined in the form of scenarios up to 2050. Nine future scenarios corresponding to three electrical demands and three options for new capacity: minimum cost of electricity, minimum CO₂ emissions and a criterion with a compromise between CO₂ and cost (CO₂-cost criterion) have been proposed. Calculations show reduction in CO₂ emissions from 2020 to 2030, reaching a maximum CO₂ emission reduction of 90% in 2050 in an efficiency scenario with CCS and renewables. The contribution of CCS from 2030 is important with percentage values of electricity production around 22–28% in 2050. The cost of electricity (COE) increases up to 25% in 2030, and then this value remains approximately constant or decreases slightly.     

Using the Median Distance to Compare Object Shapes in Content-Based Image Retrieval

Turning Angles (TAs) representation is considered one of the most interesting methods for representing object shapes in content-based image retrieval systems. Nevertheless, the distance commonly used to measure the similarity between shapes represented by TAs, the Euclidean one, is generally too sensitive to small variations in shapes.In this paper we present a new distance between shapes represented by TA, namely the Median distance, specially devised to minimize the effects of small variations in shapes. Its analytical properties are discussed and experimental results are provided and compared with those obtained by applying traditional techniques based on Euclidean distance. The Median distance has been implemented in the Automatic Image Storage and Retrieval (AISR) system, which allows storage and content-based retrieval of 2D images.     

Single-trap-induced random telegraph noise for FinFET,Si/Ge Nanowire FET,Tunnel FET,SRAM and logic circuits

In this paper, we comprehensively review the impacts of single-trap-induced random telegraph noise (RTN) on FinFET, Ge/Si Nanowire FET and Tunnel FET (TFET). The resulting influences on the thermionic-based current conduction such as FinFET, Si-NW FET and Ge-NW FET (at low drain bias) as well as interband tunneling dominated current conduction such as TFET and high-drain-biased Ge-NW FET are extensively addressed in device and circuit level. The location of the trap is shown to have profound impacts and the impacts vary with bias conditions and trap types. The worst-case analysis of the stability/performance and leakage/delay for all possible trapping/detrapping RTN combinations are investigated for FinFET, Si-/Ge-NW FETs and TFET based 6T/8T SRAM cells and logic circuits.     

A VLSI fuzzy inference processor based on a discrete analogapproach

In this paper we present a design for a general-purpose fuzzy processor, the core of which is based on an analog-numerical approach combining the inherent advantages of analog and digital implementations, above all as regards noise margins. The architectural model proposed was chosen in such a way as to obtain a processor capable of working with a considerable degree of parallelism. The internal structure of the processor is organized as a cascade of pipeline stages which perform parallel execution of the processes into which each inference can be decomposed. A particular feature of the project is the definition of a `fuzzy-gate', which executes elementary fuzzy computations, on which construction of the whole core of the processor is based. Designed using CMOS technology, the core can be integrated into a single chip and can easily be extended. The performance obtainable, in the order of 50 Mega fuzzy rules per second, is of a considerable level     

A comparison of the enantioselectivities of human deoxycytidine kinase and human cytidine deaminase

The stereoselectivities of recombinant human deoxycytidine kinase (EC 2.7.1.74) (dCK) and of recombinant human cytidine deaminase (EC 3.5.4.5) (CDA) were investigated with respect to a series of cytidine analogs, most of them having the unnatural L-stereochemistry. The enantioselectivity of dCK was always low and generally favored the L-enantiomers in the case of beta-2',3'-dideoxycytidine (beta-ddC), 5-fluoro-beta-2',3'-dideoxycytidine (beta-FddC) and beta-cytidine (beta-riboC). Concerning beta-2'-deoxycytidine, dCK showed a preference for the D-enantiomer. All other examined beta-L-cytidine analogs, [1-beta-L-lyxofuranosyl cytosine (beta-L-lyxoC), l-beta-L-xylofuranosyl cytosine (beta-L-xyloC), and 5-fluoro-1-beta-L-xylofuranosyl cytosine (beta-L-Fxylo C)], were substrates of dCK regardless of the nature of the pentose. None of the studied alpha-L-anomers (alpha-L-riboC, alpha-L-araC, alpha-L-lyxoC, or alpha-L-xyloC) was a substrate of dCK. Contrasting with the relaxed enantioselectivity of dCK, CDA had a strict requirement for D-cytidine analogs since none of the already listed beta-L- or alpha-L analogs was a substrate or an inhibitor of the enzyme. The conjunction of the preceding stereochemical properties of dCK and CDA confers to L-cytidine analogs important potentialities in antiviral and anticancer therapies.     

A Multimicrocomputer-based Structure for Computer Networking

This multiboard, Z80-based, X.25 DTE device achieves high data communications performance through a well-integrated hardware/software architecture.     

Surge arresters’ circuit models review and their application to a Hellenic 150 kV transmission line

Metal oxide surge arresters are used to protect medium and high voltage systems and equipment against lightning and switching overvoltages. Measurements of the residual voltage of the metal oxide surge arresters indicate dynamic characteristics with the residual voltage to increase as the current front time descends and the residual voltage to reach its maximum, before the arrester current reaches its peak. Thus, the metal oxide surge arresters cannot be modeled by only a non-linear resistance, since its response depends on the magnitude and the rate of rise of the surge pulse. Several frequent dependent models have been proposed, in order to simulate this dynamic frequency-dependent behavior. This study constitutes a review of the most important models, which are tested using PSCAD. The residual voltage of each model, implying 5 kA, 10 kA and 20 kA 8/20 μs impulse current, is compared with the manufacturers’ datasheet. The models are also used to study the lightning performance of a Hellenic 150 kV transmission line with the arresters implemented on every one, two or three towers, calculating their failure probability. The results show that all models function with a satisfactory accuracy and the differences among the models arise in the difficulties of the parameters’ estimation.