Cambridge Microelectronics (United Kingdom)

The rapid expansion of the brain-computer interface for patients with neurological deficits has garnered significant interest, and for patients, it provides an additional route where conventional rehabilitation has its limits. This has particularly been the case for patients who lose the ability to communicate. Circumventing neural injuries by recording from the intact cortex and subcortex has the potential to allow patients to communicate and restore self-expression. Discoveries over the last 10-15 years have been possible through advancements in technology, neuroscience, and computing. By examining studies involving intracranial brain-computer interfaces that aim to restore communication, we aimed to explore the advances made and explore where the technology is heading. For this scoping review, we systematically searched PubMed and OVID Embase. After processing the articles, the search yielded 41 articles that we included in this review. The articles predominantly assessed patients who had either suffered from amyotrophic lateral sclerosis, cervical cord injury, or brainstem stroke, resulting in tetraplegia and, in some cases, difficulty speaking. Of the intracranial implants, ten had ALS, six had brainstem stroke, and thirteen had a spinal cord injury. Stereoelectroencephalography was also used, but the results, whilst promising, are still in their infancy. Studies involving patients who were moving cursors on a screen could improve the speed of movement by optimising the interface and utilising better decoding methods. In recent years, intracortical devices have been successfully used for accurate speech-to-text and speech-to-audio decoding in patients who are unable to speak. Here, we summarise the progress made by BCIs used for communication. Speech decoding directly from the cortex can provide a novel therapeutic method to restore full, embodied communication to patients suffering from tetraplegia who otherwise cannot communicate.

A termination design which efficiently reduces leakage current and improves robustness of very high voltage insulated gate bipolar transistors (IGBTs) (>3.3 kV) without adversely affecting other device characteristics is presented here. Proposed design uses a selectively formed Buried N+ layer in the N-buffer under the termination region. Optimised placement of the N+ buried regions reduces carrier modulation in the termination area thus lowering the leakage current and reducing maximum temperature during the reverse bias safe operating area tests. This improves dynamic ruggedness of the IGBT without deteriorating other device characteristics.

This paper describes the manufacture and characterization of elastic antennas that are reversibly deformable and stretchable. The evaporation technique of depositing nanoscale thin (50/100nm) Au film on elastomer Polydimethylsiloxane (PDMS) has been developed for elastic antenna applications. A stretchable Planar Inverted-F Antenna (PIFA) based on the evaporation technology has been presented. The PIFA antenna can withstand 10% strain but gives a relatively poor efficiency. Another novel fabrication technology with comparatively thicker metal films has been developed. Stretchable metallic films can be produced by printing thick (200~400nm) silver films on PDMS. A dipole antenna is presented based on the printing technique and gives acceptable performance.

The temperature dependence of the conduction mechanism in thin films of ∼8nm diameter silicon nanocrystals is investigated using Al∕Sinanocrystal∕p-Si∕Al diodes. A film thickness of 300 nm is used. From 300 to 200 K, space charge limited current, in the presence of an exponential distribution of trapping states, dominates the conduction mechanism. Using this model, a trap density Nt=2.3×1017cm−3 and a characteristic trap temperature Tt=1670K can be extracted. The trap density is within an order of magnitude of the nanocrystal number density, suggesting that most nanocrystals trap single or a few carriers at most.

Time-resolved and time-integrated microphotoluminescence spectrometry of exciton andbiexciton transitions in a single self-assembled InGaN quantum dot gives sharp peaks, with thebiexciton 41 meV higher in energy. Theoretical modelling in the Hartree approximation (usinga self-consistent finite difference method) predicts a splitting of up to 51 meV. Time-resolvedmicrophotoluminescence measurements yield a radiative recombination lifetime of1.0 ± 0.1 ns for theexciton and 1.4 ± 0.1 ns for the biexciton. The data can be fitted to a coupled DE rate equation model,confirming that the exciton state is refilled as biexcitons undergo radiative decay.

This paper describes test software developed for both the 480 X 12 X 4 and 256 X 256 InSb focal planes manufactured at Litton EOS, Tempe, AZ. The software controls flux sources, frame grabbers and control electronics to provide a fully automated test environment. As well as providing focal plane screening and characterization, the software is an essential diagnostic tool, whereby critical performance attributes such as R0A, quantum efficiency and noise may be displayed both in histogram form and as spatial color-coded bitmap images. These bitmap images may be scanned using the mouse, so that the performance attributes of each pixel may be directly accessed. The software incorporates an emulation mode, in which the array performance is modeled in complete detail (including parameter spreads), with the data presented in identical format to that from the measured data. This allows theoretical performance to be compared directly with measured performance. The software also has the capability to perform bad pixel identification and substitution--a variety of algorithms are available--as well as detector gain/offset correction coefficients calculation.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Logic elements have been demonstrated using single-electron tunnelling transistors. The transistors are biased at different positions in the conductance oscillation cycle so that they are analogous to either n-type or p-type transistors. The circuit operation is stable at a temperature of 1.6 K despite the low gain of the transistors.