A design model for surface-termination optimization of off-statesemiconductor devices

An optimization design model for surface termination of off-state semiconductor devices under reverse-bias conditions is presented. The multivariable design model is used to optimize the surface profile shapes for nonplanar devices and the doping profiles of material regions along the surface for planar devices. The effectiveness of the design model in reducing the peak surface electric field to below 50% of the bulk value is demonstrated for two examples of each type of device     

Investigation of the geothermal anomaly of Travale (Tuscany) by telluric, magnetotelluric and geomagnetic deep sounding measurements

As part of the European Community research programme telluric, magnetotelluric and geomagnetic deep sounding measurements were undertaken at 40 sites within the geothermal area of Travale. In the period range of 6–10,000 s the telluric field inside the Travale graben is strongly polarized and directed, independent of the period, about parallel to the graben strike. The lateral variation of the telluric field amplitude is determined mainly by the distribution of the rocks (e.g. the central part of the geothermal anomaly inside the graben is correlated with a horst structure of resistive rocks) and an influence of the geothermal anomaly on the telluric field distribution cannot be observed. The apparent resistivity, as well as the phase curves, are rather similar at all sites within the graben, exhibiting 4–40 ohm · m for periods of 10 s and 50–500 ohm · m for periods of 10,000 s in E-polarization. In the period range of 10–100 s the E- and B-polarization of magnetotelluric measurements can be interpreted by the 2-D effect of the Travale graben, while with increasing period the induced current system becomes more and more 3-D below all sites. This limits the determination of the sedimentary cover thickness (max. 2500 m) by 1-D and 2-D model calculations to periods of less than 100 s.     

Hydrogen peroxide: Control of its content in water objects

A brief review of existing methods designed to determine hydrogen peroxide in aqueous media has been presented. Particular attention has been given to biosensor devices enabling us to exercise simple and express control of concentration of the specified compound.     

Autonomous mental development: soaring beyond tradition

This article provides a brief overview of the history of autonomous mental development as a discipline     

Self-powered wireless temperature sensors exploit RFID technology

Emerging RFID technology lets us embed sensors into a very small chip, creating a wireless sensing device. So, we set out to develop such a single-chip versatile temperature sensor. We also wanted to be able to transfer our design to an implantable temperature sensor for an animal healthcare application with minimal structural modification. We discuss the implementation of temperature sensor. The fully integrated complementary metal-oxide semiconductor (CMOS) batteryless device measures temperature and performs calibration to compensate for the sensor's inherent imperfections. An RF link using passive RFID's backscattering technique wirelessly transmits the data to a reading device while extracting power from the same "airwave," letting the device operate anywhere and last almost forever. The entire microchip, including the temperature sensor, consumes less than a few microamperes over a half a second, so the scanning device can capture data from longer read distances.     

The microscopy cell (MicCell), a versatile modular flowthrough system for cell biology, biomaterial research, and nanotechnology

We describe a novel microfluidic perfusion system for high-resolution microscopes. Its modular design allows pre-coating of the coverslip surface with reagents, biomolecules, or cells. A poly(dimethylsiloxane) (PDMS) layer is cast in a special molding station, using masters made by photolithography and dry etching of silicon or by photoresist patterning on glass or silicon. This channel system can be reused while the coverslip is exchanged between experiments. As normal fluidic connectors are used, the link to external, computer-programmable syringe pumps is standardized and various fluidic channel networks can be used in the same setup. The system can house hydrogel microvalves and microelectrodes close to the imaging area to control the influx of reaction partners. We present a range of applications, including single-molecule analysis by fluorescence correlation spectroscopy (FCS), manipulation of single molecules for nanostructuring by hydrodynamic flow fields or the action of motor proteins, generation of concentration gradients, trapping and stretching of live cells using optical fibers precisely mounted in the PDMS layer, and the integration of microelectrodes for actuation and sensing.