Investigations of lattice location and mobility of carbon in GaAs using the channeling technique

In order to get information about the lattice location and the mobility of ¹²C in GaAs wafers, the channeling technique in combination with nuclear reaction analysis (NRA) is a powerful method. The targets were implanted with ¹²C ions (2.6 × 10¹³−2.6 × 10¹⁵cm⁻²) at energies between 60 and 3000 keV. This corresponds to implantation depths of about 0.1 to 3 μm. Using the nuclear reaction ¹²C(d, p)¹³C a depth distribution of the implanted carbon is obtained. The relationship between the concentration of ¹⁴C in random and along the 100 and 110 axial directions gives information about the substitutional lattice location of carbon within the GaAs crystal. In addition, we measured lattice defect depth distributions with a 1.5 MeV ⁴He⁺ beam before and after thermal annealing at temperatures up to 600°C.     

Self-healing of a high temperature cured epoxy using poly(dimethylsiloxane) chemistry

A high temperature cured self-healing epoxy is demonstrated by incorporating microcapsules of poly(dimethylsiloxane) (PDMS) resin and separate microcapsules containing an organotin catalyst. Healing is triggered by crack propagation through the embedded microcapsules in the epoxy matrix, which releases the healing agents into the crack plane initiating crosslinking reactions. A series of tapered double-cantilever beam (TDCB) fracture tests were conducted to measure virgin and healed fracture toughness. Healing efficiencies, based on fracture toughness recovery, ranged from 11 to 51% depending on the molecular weight of PDMS resin, quantity of healing agent delivered, and use of adhesion promoters.     

Seeing the Objects Behind the Dots: Recognition in Videos from a Moving Camera

Category-level object recognition, segmentation, and tracking in videos becomes highly challenging when applied to sequences from a hand-held camera that features extensive motion and zooming. An additional challenge is then to develop a fully automatic video analysis system that works without manual initialization of a tracker or other human intervention, both during training and during recognition, despite background clutter and other distracting objects. Moreover, our working hypothesis states that category-level recognition is possible based only on an erratic, flickering pattern of interest point locations without extracting additional features. Compositions of these points are then tracked individually by estimating a parametric motion model. Groups of compositions segment a video frame into the various objects that are present and into background clutter. Objects can then be recognized and tracked based on the motion of their compositions and on the shape they form. Finally, the combination of this flow-based representation with an appearance-based one is investigated. Besides evaluating the approach on a challenging video categorization database with significant camera motion and clutter, we also demonstrate that it generalizes to action recognition in a natural way. Electronic Supplementary Material  The online version of this article () contains supplementary material, which is available to authorized users. This work was supported in part by the Swiss national science foundation under contract no. 200021-107636.     

Festwalzen – eine Technologie für effizienten Leichtbau

Deep Rolling – a technology for efficient lightweight design Deep rolling is a proven method for increasing the fatigue strength of dynamically loaded parts. Although this application has been used for many years, procedures that induce work hardening and residual stresses are not well known. This article concerns both deep rolling and the potential for considering the resultant residual stresses in the design phase of components to achieve efficient lightweight design. In addition, the article includes new research results regarding the numerical modelling of deep rolling.     

Adenosine receptor antagonism in refractory asystolic cardiac arrest: results of a human pilot study

A new method for orthodontic treatment of cross bite in permanent dentition is demonstrated. This method makes the treatment of cross bites as a modification of light-wire loop system more fastly and effectively.     

Development of an incremental rolling process for the production of defined riblet surface structures

Viscous drag reduction on fan, compressor and turbine blades may be achieved by employing a riblet surface structure. Such a structure assists in increasing efficiency and in reducing energy consumption in flow applications. In order to produce riblet surface structures industrially, a new and incremental rolling process is being developed and investigated. The process design is being determined by common airstream requirements as well as the forming mechanisms that are predominant during the rolling process. Based on this principle, the required shape of the structured rollers is being developed. Research is focused on the feasibility of manufacturing small riblet structures at a size of a few hundred microns. Experimental production of different riblet geometries made from Ti-6Al-4V (WL 3.7164) provides some initial insights with respect to feasibility, shape accuracy, surface quality, and micro structure.     

Laser Zone Melting and microstructure of waveguide coatings obtained on soda-lime glass

This study presents a Laser Zone Melting method with potential for producing planar waveguides at large scale, based on the surface coupling of two chemically compatible glass layers which exhibit distinct indices of refraction. The method is based on a recent patent, particularly applicable to process glass and ceramics with low thermal shock resistance. Glass coatings containing 76.24% by weight PbO are thus here reported, as obtained by this method on commercial soda-lime planar glass substrates. Their higher indices of refraction (1.58 vs 1.52 for commercial soda-lime glass) result in attractive waveguiding potential, as demonstrated with measurements using focused light from a He-Ne laser beam. Scanning and transmission electron microscopy studies reveal excellent integration and compatibility between the observed coatings and substrates, where diffusion in the proximity of the interface was studied by EDS analysis. Crystalline phases have not been found within the coating, or within the substrate, as concluded from the absence of Bragg-peaks in XRD experiments.