Reactivity at the Cu2O(100):Cu-H2O interface: a combined DFT and PES study.

The water-cuprite interface plays an important role in dictating surface related properties. This not only applies to the oxide, but also to metallic copper, which is covered by an oxide film under typical operational conditions. In order to extend the currently scarce knowledge of the details of the water-oxide interplay, water interactions and reactions on a common Cu2O(100):Cu surface have been studied using high-resolution photoelectron spectroscopy (PES) as well as Hubbard U and dispersion corrected density functional theory (PBE-D3+U) calculations up to a bilayer water coverage. The PBE-D3+U results are compared with PBE, PBE-D3 and hybrid HSE06-D3 calculation results. Both computational and experimental results support a thermodynamically favored, and H2O coverage independent, surface OH coverage of 0.25-0.5 ML, which is larger than the previously reported value. The computations indicate that the results are consistent also for ambient temperatures under wet/humid and oxygen lean conditions. In addition, both DFT and PES results indicate that the initial (3,0;1,1) surface reconstruction is lifted upon water adsorption to form an unreconstructed (1 × 1) Cu2O(100) structure.

An approach to analyze the movements of the arms while walking using wearable wireless devices.

Rhythmic movement of the arms while walking is an important feature of human gait. In this paper, we present an approach to analyze the movements of the arms while walking by using three wearable wireless devices placed around the torso. One of the devices is transmitter placed at the back and the other two are symmetrically placed receivers that record the power variation due to movements of the arms while walking. We show that the power received by the receivers will have symmetrical variation if the arms' swing is symmetrical. An analytical model has been used to calculate the position of the receivers. Full wave simulations on a walking phantom are done to confirm the results.

Spike-feature based estimation of electrode position in extracellular neural recordings.

Detecting and sorting spikes in extracellular neural recordings are common procedures in assessing the activity of individual neurons. In chronic recordings, passive electrode movements introduce changes in the shape of detected spike waveforms, and may thus lead to problems with identification and tracking of spikes recorded at separate instances in time, which is an important step in long-term monitoring of individual neurons. Information about electrode movements after implantation is crucial to the evaluation of mechanical stability of different electrode designs. In this paper, we present a preliminary study of the relationship between electrode movements and the resulting movements of spike-features in feature space. We show that there is a characteristic relationship between the two movements and that this relationship can be modeled as a linear transformation between two coordinate systems. Finally, we show how the relationship can be used for estimating electrode positions based on measured spike waveforms without any prior knowledge about the type of neuron by introducing a learning procedure during electrode insertion.

Effect of frequency, body parts and surrounding on the on-body propagation channel around the torso.

Wearable medical devices can be positioned around the torso for monitoring of critical health parameters. The signal transmission between them is through a wireless link over an on-body propagation channel. In this paper, the effect of some factors which could influence the propagation channel around the torso as: (a) frequency of operation (b) positions of the arms (c) material of a chair used, have been investigated. Moreover, a comparison between the link loss around the torso of a full body phantom and a truncated torso phantom has been done. It is found that the frequency of operation and the positions of the arms have a significant influence on the channel. The difference between the link loss of a full body phantom and a truncated phantom is found to be minimal, indicating a possibility of using a truncated torso for a faster simulation. The results presented in the paper gives an insight in to the influence of arms and the frequency of operation on the propagation channel around the torso and thus would be beneficial for designing a reliable wireless link.

In-mouth antenna for tongue controlled wireless devices: characteristics and link-loss.

We have investigated the possibility of using a curved dipole antenna inside the mouth for the tongue controlled wireless devices in 2.45 GHz ISM band. These devices can be interfaced with the wheelchair or the computer used by the paraplegic patients. Two antenna placement positions have been investigated: in front of the teeth and behind the teeth. The investigations were done through the FDTD simulations on a realistic heterogeneous phantom with the mouth closed and open. The link loss between the in-mouth dipole antenna and an external dipole antenna at 400 mm from the center of the head was calculated. It was found that the radiation pattern changed according to the placement of the antennas inside the mouth and whether the mouth was open or closed. The link loss for the in front of the teeth placement was found to be 9 dB-11 dB lower than the behind the teeth placement depending on the open or the closed mouth. The variation in the link loss was 1 dB-4 dB for the open mouth when compared with the closed mouth depending on the antenna placement position. By using these results, a reliable wireless link for the in-mouth device can be designed.

Implementation of a telemetry system for neurophysiological signals.

With an ever increasing need for assessment of neurophysiological activity in connection with injury and basic research, the demand for an efficient and reliable data acquisition system rises. Brain-machine interfaces is one class of such systems that targets the central nervous system. A necessary step in the development of a brain-machine interface is to design and implement a reliable and efficient measurement system for neurophysiological signals. The use of telemetric devices increases the flexibility of the devices in terms of subject mobility and unobtrusiveness of the equipment. In this paper, we present a complete system architecture for a wearable telemetry system for the acquisition of neurophysiological data. The system has been miniaturized and implemented using surface-mount technology. System performance has been successfully verified and bottlenecks in the architecture have been identified.