Judit Kaman

A review on current eCall systems for autonomous car accident detection

The aim of the paper is to give an overview on the existing eCall solutions for autonomous car accident detection. The requirements and expectations for such systems, considering both technological possibilities, legal regulatory criteria and market demands are discussed. Sensors utilized in e-call systems (crash sensing, systems for positional and velocity data, and communication solutions) are overviewed in the paper. Furthermore, the existing solutions for eCall devices are compared based on their level of autonomy, technical implementation and provided services.

Investigation of the AFM contact-mode force calibration with simulation

Force-curves measured by Atomic Force Microscopy (AFM) are frequently used to determine the local Youngs Modulus of the sample. Originally the AFM (Atomic Force Microscopy) instruments measure the cantilever deflection as a voltage signal; however the natural unit of the deflection is nanometer. In general, the V/nm conversion factor is determined from the force-curve of a hard sample. Since this conversion is highly affects the value of the Youngs modulus, the accuracy of this method was investigated experimentally and using a finite element simulation of the cantilever motion. It was found, that the position of the laser spot significantly modify the conversion factor and in case of the sample with steep surface, the error of this calibration method can be significant.

Investigation of the Local Mechanical Properties of the SAC Solder Joint with AFM

Considering the size of the natural appearance of the micro alloy components of a SAC solder joint, AFM was used to investigate their mechanical properties in the form of their natural appearance. Contact-mode point-spectroscopy was done to determine the elastic modulus and tapping-mode point-spectroscopy was done to investigate the tip-sample power dissipation.The measured Young’s modulus values of the Cu, IML, Ag3Sn and Sn components, were 125±9 GPa, 111±20 GPa, 67±11 GPa and 57±16 GPa, respectively. The dissipation measurements were accomplished by Si and diamond probes with different spring constants. The different characteristics of the results are discussed.

Characterization of the shape of gold nanoparticles prepared by thermal annealing

Gold nanoparticles - which are intended to be used as transducers in a localized surface plasmon resonance (LSPR) sensor - were prepared by thermally annealing various layers of gold thin films deposited on glass substrate. The size and distribution of nanoparticles were investigated by atomic force microscopy (AFM). The changes in the nanoparticle shape in function of the deposition and annealing parameters are characterized. A novel parameter called localization factor was used to investigate the shape of the resulting particles. A common problem concerning the AFM imaging of nanoparticles, namely the tip convolution effect was studied, and possibilities to use the localization factor parameter to optimize surface reconstruction algorithms via tip deconvolution is demonstrated.

Investigation of mechanical properties of the generated surface structures on a chalcogenide thin film with AFM

Light induced holographic grating and electron beam induced stripes were created on Ge28Se72 chalcogenide thin film and its local surface mechanical properties were studied by AFM. The Youngs moduli of the grating, the stripes and the reference area were determined through force curves and the tip-sample energy dissipation was calculated from the tapping mode point spectroscopy curves. Significant difference was obtained between the created structures and the reference area regarding the Youngs modulus and the tip-sample energy dissipation.

Investigation of surface mechanical properties of the copper-solder interface by atomic force microscopy

In this work, the possibility to characterize the mechanical surface properties of solder-joints with AFM techniques was studied. A SAC305 solder joint cross-section was investigated with contact-mode point-spectroscopy to determine the elastic modulus, while tapping-mode imaging was used to calculate the tip-sample dissipation map. A clear advantage of these proposed methods would be the possibility to distinguish the various micro- and nanoscale components of the solder joint structure (intermetallic compounds) and measure their properties individually, which is not possible with other currently widespread methods (e.g. indentation). Our presented preliminary results show, that the mechanical properties of the Cu6Sn5 compound at the solder interface are closer to Cu compared to the much less harder Sn. The difficulties to obtain precise quantitative results with these proposed methods will also be discussed.

Elastic modulus and energy dissipation measurements with AFM on chalcogenide thin films

Contact-mode point spectroscopy and tapping-mode imaging atomic force microscopy (AFM) techniques were used to measure the Youngs Modulus and tip-surface energy dissipation of amorphous chalcogenide thin films. As20Se80 thin film was prepared by thermal evaporation on glass substrates, and a He-Ne laser (633 nm) was used to prepare a holographic grating on the thin film. The results from both AFM measurement techniques indicate that there are significant differences between the peaks and valleys of the grating in terms of elasticity and tip-surface energy dissipation.