Silicon-substrate microelectrode arrays for parallel recording ofneural activity in peripheral and cranial nerves

A new process for the fabrication of regeneration microelectrode arrays for peripheral and cranial nerve applications is presented. This type of array is implanted between the severed ends of nerves, the axons of which regenerate through via holes in the silicon and are thereafter held fixed with respect to the microelectrodes. The process described is designed for compatibility with industry-standard CMOS or BiCMOS processes (it does not involve high-temperature process steps nor heavily-doped etch-stop layers), and provides a thin membrane for the via holes, surrounded by a thick silicon supporting rim. Many basic questions remain regarding the optimum via hole and microelectrode geometries in terms of both biological and electrical performance of the implants, and therefore passive versions were fabricated as tools for addressing these issues in on-going work. Versions of the devices were implanted in the rat peroneal nerve and in the frog auditory nerve. In both cases, regeneration was verified histologically and it was observed that the regenerated nerves had reorganized into microfascicles containing both myelinated and unmyelinated axons and corresponding to the grid pattern of the via holes. These microelectrode arrays were shown to allow the recording of action potential signals in both the peripheral and cranial nerve settings, from several microelectrodes in parallel     

Early detection of ageing in solder joints through laser probe thermal analysis of the peltier effect

We have recently developed an optical contactless method for testing the quality of solder joints during accelerated thermal cycling ageing processes.¹ The method was based upon the measurement of the dynamic thermal behaviour of the joint to short bursts of Joule heating. It has proved to be efficient in revealing the formation of cracks at the lead-solder interface. We present a method to evaluate ageing at a much earlier stage in the cycling process. We have observed in earlier work,¹ that before cracks appear, structural changes occur in the solder at the lead-solder interface. The thermal response of the solder joint is recorded over time to a Peltier heat perturbation produced by flowing a current pulse through the interface where structural changes occur. The key point in this method is to discriminate the Peltier effect from the Joule thermal response because both effects generate heat. The variation of the early Peltier response in the thermal cycling ageing tests is seen as a quantitative signature of the structural changes in the lead-solder interface.     

Kalman decomposition for implicit linear systems

The Kalman decomposition for a general class of implicit systems is introduced and studied. The properties of strong reachability, observability, acceptance of all inputs and outer sequences, output-uniqueness, uniqueness, and trajectory observability of the original system are related to the properties of its subsystems obtained via the Kalman decomposition. The problems of transfer relation, regularizability by feedback, output feedback, and output injection are studied by means of this decomposition     

Cars, phones, and Tamagotchi tribes

As if life isn't already crowded enough with obligations, “Tamagotchis” (virtual pets) would seem to be at odds with the Information Age, but cars, phones and TV-like appliances will become more like Tamagotchis as the friction-free economy once again expresses itself in tribalism. My premise is simple: the friction-free economy rewards retro-cultures that yearn to return to agrarian tribalism. Selling hi-tech products in this new economy becomes ritual, and the greater the ritual, the greater the financial rewards. Some may use different names-database marketing, targeting or niche marketing-but the key to expanding the computer industry will be to build a tribe around your brand and flaunt it. Successful product design and sales will increasingly require targeting products, services and ideas to various tribes. An idea long understood in the entertainment and services industry, this is only now becoming a computer industry mantra. The question is, how will this impact the design of future computer products? Study the Tamagotchi and other Christmas season best-sellers to find out     

A mixed-signal RAM decision-feedback equalizer for disk drives

A mixed-signal RAM decision-feedback equalizer (DFE) that operates at 90 Mb/s is described. In the analog domain, the DFE subtracts intersymbol interference caused by the past four outputs. The equalized signal is fed into a nonuniform flash analog-to-digital converter (ADC) to produce the decision output and error signal used to adapt the RAM contents in the digital domain. With a 5 V supply voltage, the power dissipation is 260 mW during steady-state operation. The active area is 4.5 mm² in a 1 μm CMOS process     

Technique for Producing Mullite and Other Mixed-Oxide Systems

Mixed-oxide systems are of interest in a variety of technical ceramic applications. The key in many systems is to achieve a high degree of homogeneity, approaching the molecular level. A technique for producing mixed oxides via direct oxidation of mixtures of organometallic compounds is discussed as a potential route. Preliminary work performed on producing mullite is discussed.     

Neural Network Feedback Control: Work at UTA’s Automation and Robotics Research Institute

This is an outline of research in neural networks for feedback control done since the mid 1990s at the Automation and Robotics Research Institute (ARRI) of The University of Texas at Arlington (UTA). It shows how the developments of Intelligent Control Systems based on neural networks have followed three main generations. This statement provides a short, broad-brush perspective on the development of intelligent neural feedback controllers.