Correlation between density of states distributions and the fermi level position in interfacial regions of amorphous silicon thin film transistors

This paper investigates the variation of the integrated density of states with conduction activation energy in hydrogenated amorphous silicon thin film transistors. Results are given for two different gate insulator layers, PECVD silicon oxide and thermally grown silicon dioxide. The different gate insulators produce transistors with very different initial transfer characteristics, but the variation of integrated density of states with conduction activation energy is shown to be similar.

Losses in self-oscillating ballasts for electrode-type compact fluorescent lamps

Commercially available integrated compact fluorescent lamps (CFLs) use self-resonant ballasts on grounds of simplicity and cost. To understand how to improve ballast efficiency, it is necessary to quantify the losses. The losses occurring in these ballasts have been directly measured using a precision mini-calorimeter. In addition, a Pspice model has been used to simulate the performance of an 18 W integrated CFL. The lamp has been represented by a behavioural model and Jiles-Atherton equations were used to model the current transformer core. The total loss is in close agreement with measurements from the mini-calorimeter, confirming the accuracy of the model. The total loss was then disaggregated into component losses by simulation, showing that the output inductor is the primary source of loss, followed by the inverter switches. © 2011 The Institution of Engineering and Technology.

Paraphyly of Chinese Amolops (Anura, Ranidae) and phylogenetic position of the rare Chinese frog, Amolops tormotus

In order to evaluate the five species groups of Chinese Amolops based on morphological characteristics, and to clarify the phylogenetic position of the concave-eared torrent frog Amolops tormotus, we investigated the phylogeny of Amolops by maximum parsim

Adaptive control of stiffness to stabilize hand position with large loads.

The goal of this work was to investigate stability in relation to the magnitude and direction of forces applied by the hand. The endpoint stiffness and joint stiffness of the arm were measured during a postural task in which subjects exerted up to 30% maximum voluntary force in each of four directions while controlling the position of the hand. All four coefficients of the joint stiffness matrix were found to vary linearly with both elbow and shoulder torque. This contrasts with the results of a previous study, which employed a force control task and concluded that the joint stiffness coefficients varied linearly with either shoulder or elbow torque but not both. Joint stiffness was transformed into endpoint stiffness to compare the effect on stability as endpoint force increased. When the joint stiffness coefficients were modeled as varying with the net torque at only one joint, as in the previous study, we found that hand position became unstable if endpoint force exceeded about 22 N in a specific direction. This did not occur when the joint stiffness coefficients were modeled as varying with the net torque at both joints, as in the present study. Rather, hand position became increasingly more stable as endpoint force increased for all directions of applied force. Our analysis suggests that co-contraction of biarticular muscles was primarily responsible for the increased stability. This clearly demonstrates how the central nervous system can selectively adapt the impedance of the arm in a specific direction to stabilize hand position when the force applied by the hand has a destabilizing effect in that direction.

A vertically aligned carbon nanotube/fiber based electrode for economic hydrogen production by water electrolysis

Electrolysis is the most mature form of hydrogen production. Unfortunately, water electrolysis has not yet achieved the efficiency and the cost levels required for any practical application. In order to enhance the current density, modification of the electrolyte and the electrode morphology are the most popular approaches. Recently there have been numerous reports on how to improve the efficiency of hydrogen production by water splitting [1-3]. On the electrode side, the use of non-platinum high efficiency electrode materials for water splitting will provide a promising future for the hydrogen economy. An ideal electrode for water electrolysis should have good permeability to water and gas. It should also offer good electrical properties with a long life. A porous graphite plate, when coated with titania, for example, is known to provide a simple and economical electrode for water electrolysis [4]. © 2010 IEEE.

The morphology of decorated amyloid fibers is controlled by the conformation and position of the displayed protein.

Self-assembled structures capable of mediating electron transfer are an attractive scientific and technological goal. Therefore, systematic variants of SH3-Cytochrome b(562) fusion proteins were designed to make amyloid fibers displaying heme-b(562) electron transfer complexes. TEM and AFM data show that fiber morphology responds systematically to placement of b(562) within the fusion proteins. UV-vis spectroscopy shows that, for the fusion proteins under test, only half the fiber-borne b(562) binds heme with high affinity. Cofactor binding also improves the AFM imaging properties and changes the fiber morphology through changes in cytochrome conformation. Systematic observations and measurements of fiber geometry suggest that longitudinal registry of subfilaments within the fiber, mediated by the interaction and conformation of the displayed proteins and their interaction with surfaces, gives rise to the observed morphologies, including defects and kinks. Of most interest is the role of small molecule modulation of fiber structure and mechanical stability. A minimum complexity model is proposed to capture and explain the fiber morphology in the light of these results. Understanding the complex interplay between these factors will enable a fiber design that supports longitudinal electron transfer.

Optimization of nanotube electrode geometry in a liquid crystal media from wavefront aberrations

This paper presents experimental optimization of number and geometry of nanotube electrodes in a liquid crystal media from wavefront aberrations for realizing nanophotonic devices. The refractive-index gradient profiles from different nanotube geometries-arrays of one, three, four, and five-were studied along with wavefront aberrations using Zernike polynomials. The optimizations help the device to make application in the areas of voltage reconfigurable microlens arrays, high-resolution displays, wavefront sensors, holograms, and phase modulators. © 2012 Optical Society of America.

Phylogenetic analysis of the family Thermaceae with an emphasis on signature position and secondary structure of 16S rRNA

The sequences of the 16S rRNA genes from 38 strains of the family Thermaceae were compared by alignment analysis. The genus-specific and species-specific base substitutions or base deletions (signature positions) were found in three hypervariable regions (in the helices 6, 10 and 17). The differentiation of secondary structures of the high variable regions in the 5' end (38-497) containing several signature positions further supported the concept. Based on the comparisons of the secondary structures in the segments of 16S rRNAs, a key to the species of the family Thermaceae was proposed. (C) 2003 Published by Elsevier Science B.V. on behalf of the Federation of European Microbiological Societies.