The resistance of an infinite slab with a disc electrode as a mixed boundary value problem

We consider the resistance of an infinite slab of material with a disc contact source on one side and with current collected over the entire back plane. By imposing the boundary condition of a constant potential over the source region, the problem becomes one of mixed boundary conditions, requiring the solution of a pair of dual integral equations. These equations are solved in terms of a Fredholm integral equation of the second kind.Calculations of the resistance are performed for values of slab thicknesses ranging from 0·05 to 4 times the disc contact radius, and the solutions obtained agree closely with Foxhall and Lewis' electrolytic tank measurements. The results are used to establish the range of validity of two approximate methods previously proposed for correction factor calculations in spreading resistance measurements on semiconductor device structures.     

Tensile behavior and deformation mechanisms of bulk ultrafine-grained copper

The tensile behaviors of the ultrafine-grained (UFG) pure copper prepared by cold rolling have been investigated. The UFG-Cu exhibited high strengths and low ductility. The ductile dimple-like fracture surfaces and persistent-slip-bands (PSBs)-like local shear bands in the tension-deformed UFG-Cu were observed, both of which typically spanned tens of grain sizes. This observation indicated that the fracture mechanisms operated at a larger scale than the grain size and eventually involved collective grain activities. Moreover, localized shear bands provided the experimental evidence to the localized plastic deformation, which was the one of the dominant reasons, causing the low ductility in the UFG-Cu.     

An Efficient Data Dissemination Scheme for Spatial Query Processing

Due to the personal portable devices and advances in wireless communication technologies, Location Dependent Information Services （LDISs） have received a lot of attention from both the industrial and academic communities. In LDISs, it is important to reduce the query response time, since a late query response may contain out-of-date information. In this paper, we study the issue of LDISs using a Voronoi Diagram. We introduce a new NN search method, called the Exponential Sequence Scheme （ESS）, to support NN query processing in periodic broadcast environment. This paper aims to provide research directions towards minimizing both the access latency and energy consumption for the NN-query processing.     

Entropies for detection of epilepsy in EEG

The electroencephalogram (EEG) is a representative signal containing information about the condition of the brain. The shape of the wave may contain useful information about the state of the brain. However, the human observer cannot directly monitor these subtle details. Besides, since bio-signals are highly subjective, the symptoms may appear at random in the time scale. Therefore, the EEG signal parameters, extracted and analyzed using computers, are highly useful in diagnostics. The aim of this work is to compare the different entropy estimators when applied to EEG data from normal and epileptic subjects. The results obtained indicate that entropy estimators can distinguish normal and epileptic EEG data with more than 95% confidence (using t-test). The classification ability of the entropy measures is tested using ANFIS classifier. The results are promising and a classification accuracy of about 90% is achieved.     

Ultrafast surface enhanced resonance Raman scattering detection in droplet-based microfluidic systems

The development of ultrafast Raman-based detection is one of the most interesting challenges underpinning the application of droplet-based microfluidics. Herein, we describe the use of surface-enhanced resonance Raman spectroscopy (SERRS) with submillisecond time resolution as a powerful detection tool in microdroplet reactors. Individual droplets containing silver nanoparticle aggregates functionalized with Raman reporters are interrogated and characterized by full spectra acquisitions with high spatial resolution in real time. Whereas previous works coupling SERRS with droplet-based microfluidics acquire a single spectrum over single or multiple droplets, we build upon these results by increasing our temporal resolution by 2 orders of magnitude. This allows us to interrogate multiple points within one individual droplet. The SERRS signals emitted from the aggregates are utilized to access the influence of flow rate on droplet size and throughput. Accordingly, our approach allows for high-throughput analysis that facilitates the study of other biological assays or molecular interactions.     

Ink Processing for Thermoelectric Materials and Power‐Generating Devices

The growing concern over the depletion of hydrocarbon resources, and the adverse environmental effects associated with their use, has increased the demand for renewable energy sources. Thermoelectric (TE) power generation from waste heat has emerged as a renewable energy source that does not generate any pollutants. Recently, ink‐based processing for the preparation of TE materials has attracted tremendous attention because of the simplicity in design of power generators and the possibility of cost‐effective manufacturing. In this progress report, recent advances in the development of TE inks, processing techniques, and ink‐fabricated devices are reviewed. A summary of typical formulations of TE materials as inks is included, as well as a discussion on various ink‐based fabrication methods, with several examples of newly designed devices fabricated using these techniques. Finally, the prospects of this field with respect to the industrialization of TE power generation technology are presented.     

Residual stress generation in metal matrix composites after cooling

Effects of reinforcements’ shapes, sizes and contents on (a) von-Mises stress along a horizontal line in MMCs, (b) directions and distributions of principal stresses inside particles, matrix and interface, and (c) distribution of thermal residual stress in MMCs were analysed in this investigation. It was found that the matrix–particle interfaces experience a sudden change of von-Mises stress which depends on the reinforcement shape. The smoothest change of stress occurred in triangle particle-reinforced MMCs. However, the highest stress was concentrated at the corners of the triangular particles. The directions of stress vectors depend on the shape of the particles. The extent of the von-Mises stress increases with the increase in reinforcement content and a decrease in particles size at constant content.