Synchronous current control scheme with reference voltage estimation for voltage-fed PWM inverter

A new current control scheme with the reference voltage estimation for a voltage-fed pulsewidth modulated (PWM) inverter is presented. This scheme is simple and can provide smaller current error than predictive control with the same switching frequency when the load parameters are mismatched.<>     

Monitoring of TiSi2 formation on narrow polycrystallinesilicon lines using Raman spectroscopy

Micro-Raman spectroscopy is used to monitor titanium silicide (TiSi₂) formation on narrow undoped polycrystalline silicon lines. Linewidths varying from 1.0 μm down to 0.35 μm, with silicidation by rapid thermal anneal (RTA) temperature ranging between 780°C and 1020°C were analyzed. Phase changes between C49 and C54-TiSi₂ phases were clearly observed. Results demonstrate that analysis of the C54-TiSi₂ Raman peak intensity allowed fast and nondestructive estimation of the process window for low resistivity C54-TiSi₂ formation. Comparison with sheet resistivity measurements showed that micro-Raman scattering provides a complimentary means to electrical analysis for the study of TiSi₂ formation     

Laser-effected darkening in TPEs with TiO2 additives

Investigations were carried out for laser-effected darkening and damage-free laser marking on thermoplastic elastomers (TPEs). Titanium dioxide (TiO₂) was studied as the laser-sensitive additive to the TPEs for its role in enhancing laser marking contrast and its effect on the TPE properties. Laser beam characteristics, processing variables and percentage loading of TiO₂ in the TPEs were found to have significant effect on the marking contrast. Surface damage-free and high contrast marking have been achieved with short pulse UV lasers. The laser-effected darkening was found to penetrate into the material in the order of a few tens of microns. XPS analysis was carried out to understand the laser-effected darkening mechanism. Potential applications of the technique are highlighted.     

An extension of whitney’s theorem to infinite strong triangulations

In this paper, the existence of one-way infinite Hamiltonian paths in an infinite 4-connected strong triangulation is constructively verified, which is an extension of WHITNEY’S theorem to infinite graphs.     

Spatial chaos aspects of laser-material interaction

In the past decade the understanding of stability and chaotic behaviour of nonlinear systems has made significant progress. Such systems include: structure of turbulence, oscillations in mechanical structures, multistable biological systems, etc. Laser machining is now an established industrial production method for: prototyping, small batch manufacture, cutting refractory materials and specialist applications such as micromachining. Within narrowly bounded limits, many models exist that can be used to predict the necessary machining control parameters such as cutting rate, power, pulse repetition frequency, etc. However, in an unconstrained machining process, chaotic phenomena can be observed to occur. The objective of this paper is to prove the existence of chaos, for the laser-material interaction, which can be described by Poincaré-Birkhoff-Smale horseshoes. Furthermore, to exploit the phase portrait of the process to predict the optimal laser machining control parameters.     

Panorama field rendering with scene depth estimation

A novel approach to image-based modelling and rendering is proposed. A set of randomly placed panoramas and omnidirectional depth information of the surrounding scene are used to generate an output image at a vantage viewpoint. Implementation results show that the proposed approach achieves smooth walkthrough at a realtime     

Mössbauer- and EPR-Snapshots of an Enzymatic Reaction: The Cytochrome P450 Reaction Cycle

Hyperfine Interactions - In this communication we present a complimentary Mössbauer- and EPR-study of the time dependance of the reaction of substrate free P450cam with peracetic acid within a...     

Charged particle multiplicity distributions ine + e − annihilation at 29 GeV: a comparison with hadronic data

The charged particle multiplicity distributions for two-jet events ine ⁺ e ^? annihilation at 29 GeV have been measured using the High Resolution Spectrometer at PEP. A Poisson distribution describes the data for both the complete event and for the single jets. In addition, no correlation is observed between the multiplicities in the two jets of an event. For fixed values of the prong number of the complete event, the multiplicity sharing between the two jets is in good agreement with a binomial distribution. The rapidity gap distribution is exponential with a slope equal to the mean rapidity density. These observations, which are consistent with a picture of independent emission of single particles, are contrasted to the results from soft hadronic collisions and conclusions are drawn about the nature of clusters.