Fabrication of submicron planar Gunn diode

We present, for the first time, the fabrication process for a submicron planar Gunn diode in In<sub>0.53</sub>Ga<sub>0.47</sub>As on an InP substrate operating at 265 GHz. A novel two stage lift off method has been developed to achieve a submicron gaps between contacts down to 135 nm with widths up to 120 μm

Meeting the design challenges of nano-CMOS electronics: an introduction to an upcoming EPSRC pilot project

The years of ‘happy scaling’ are over and the fundamental challenges that the semiconductor industry faces, at both technology and device level, will impinge deeply upon the design of future integrated circuits and systems. This paper provides an introduction to these challenges and gives an overview of the Grid infrastructure that will be developed as part of a recently funded EPSRC pilot project to address them, and we hope, which will revolutionise the electronics design industry

Monolithic Implementation of a Planar Gunn Diode and a pHEMT

No abstract available

Interactive manipulation of microparticles in an octagonal sonotweezer

An ultrasonic device for micro-patterning and precision manipulation of micrometre-scale particles is demonstrated. The device is formed using eight piezoelectric transducers shaped into an octagonal cavity. By exciting combinations of transducers simultaneously, with a controlled phase delay between them, different acoustic landscapes can be created, patterning micro-particles into lines, squares, and more complex shapes. When operated with all eight transducers the device can, with appropriate phase control, manipulate the two dimensional acoustic pressure gradient; it thus has the ability to position and translate a single tweezing zone to different locations on a surface in a precise and programmable manner

Dynamic acoustic field activated cell separation (DAFACS)

Advances in diagnostics, cell and stem cell technologies drive the development of application-specific tools for cell and particle separation. Acoustic micro-particle separation offers a promising avenue for highthroughput, label-free, high recovery, cell and particle separation and isolation in regenerative medicine. Here, we demonstrate a novel approach utilizing a dynamic acoustic field that is capable of separating an arbitrary size range of cells. We first demonstrate the method for the separation of particles with different diameters between 6 and 45 μm and secondly particles of different densities in a heterogeneous medium. The dynamic acoustic field is then used to separate dorsal root ganglion cells. The shearless, label-free and low damage characteristics make this method of manipulation particularly suited for biological applications. Advantages of using a dynamic acoustic field for the separation of cells include its inherent safety and biocompatibility, the possibility to operate over large distances (centimetres), high purity (ratio of particle population, up to 100%), and high efficiency (ratio of separated particles over total number of particles to separate, up to 100%)

Content retrieval and mobile users: An outdoor investigation of an ambient travel guide

People's information needs change as they encounter new situations. The need for an ambient information environment becomes more evident in the case of the mobile traveller where situated information access is one of the main challenges. The motivation for this work has been to provide relevant information to the right situation and user in an ambient manner. Our way to solve this is to deliver personalised and context-aware information to the mobile user. To this end we have developed a platform, and prototype applications for travellers, and tourists. The system integrates our own tag technology with information from content service providers covering both general travel guide and local information. The development methodology is user-centred, iterative, and progressive in nature. It combines information retrieval (IR) test and evaluation techniques with iterative and user-centred development techniques at the test and evaluation phase. Combining the two disciplines gives us the ability to test and evaluate both the information aspects and the interaction aspects of any information system in parallel. Another advantage would be that one can develop content and software in parallel. This paper focuses on the IR test and evaluation framework that has been used in conjunction with the user-centred development. We emphasize the importance of performing IR test and evaluation for mobile systems in terms of users’ situations and tasks. The paper presents the results of some of the findings from a preliminary user test in an outdoor scenario. The test took place in a popular tourist destination in Spain

Quantifying cross-scale patch contributions to spatial connectivity

Context: Connectivity between habitat patches is vital for ecological processes at multiple scales. Traditional metrics do not measure the scales at which individual habitat patches contribute to the overall ecological connectivity of the landscape. Connectivity has previously been evaluated at several different scales based on the dispersal capabilities of particular organisms, but these approaches are data-heavy and conditioned on just a few species. Objectives: Our objective was to improve cross-scale measurement of connectivity by developing and testing a new landscape metric, cross-scale centrality. Methods: Cross-scale centrality (CSC) integrates over measurements of patch centrality at different scales (hypothetical dispersal distances) to quantify the cross-scale contribution of each individual habitat patch to overall landscape or seascape connectivity. We tested CSC against an independent metapopulation simulation model and demonstrated its potential application in conservation planning by comparison to an alternative approach that used individual dispersal data. Results: CSC correlated significantly with total patch occupancy across the entire landscape in our metapopulation simulation, while being much faster and easier to calculate. Standard conservation planning software (Marxan) using dispersal data was weaker than CSC at capturing locations with high cross-scale connectivity. Conclusions: Metrics that measure pattern across multiple scales are much faster and more efficient than full simulation models and more rigorous and interpretable than ad hoc incorporation of connectivity into conservation plans. In reality, connectivity matters for many different organisms across many different scales. Metrics like CSC that quantify landscape pattern across multiple different scales can make a valuable contribution to multi-scale landscape measurement, planning, and management

Micro-cooler Enhancements by Barrier Interface Analysis

Peer reviewedPublisher PD