Effects of Thermo-mechanical Loading From In-situ Studies of EB-PVD Thermal Barrier Coatings

The thermo-mechanical effects on the strain evolution within an EB-PVD thermal barrier coating (TBC) is presented in this work using in-situ characterization. Synchrotron X-ray diffraction at sector 1-ID at the Argonne National Laboratory provided both qualitative and quantitative in-situ data on the strain evolution under a thermal cycle with mechanical loading. The results show that at a critical combination of temperature and load, the stress in the thermally grown oxide (TGO) layer in the TBC reaches a tensile region. These significant findings enhance existing literature showing purely compressive strains within the TGO where mechanical loads have been neglected. The results have important implications on the effects on the overall life of the coating. Depth resolved quantitative strain is presented as contour plots over a thermal cycle highlighting the complementary strains in the adjacent layers including the bond coat and the TBC with time and temperature. Systematic identification of the appropriate peaks within the multi-layer TBC system provides guidelines for future strain studies using high energy X-rays. Piezospectroscopic studies with applied mechanical loading are further presented as verification of the room temperature XRD data for future development of the method as an operational technique to be used outside the laboratory environment

Device structure effects on electrical crosstalk in Backwall Illuminated CMOS compatible photodiode arrays

This research has made a comparative investigated of crosstalk in backside illuminated and frontside illuminated single junction photodiode and vertical double junction photodiode CMOS compatible pixels, using a commercial 2D device simulation package, SEMICAD DEVICE (1994). Comparison of pixel total, electron and hole quantum efficiency response and Absorption Volume data is undertaken. This is so that the underlying carrier drift-diffusion dynamics responsible for optimal pixel response resolution may be qualitatively understood, allowing prediction of even more optimal photodiode pixel configurations. The effect of varying the double junction and single junction photodiode pixel\u27s geometry on response resolution is considered. Only for the former is the effect of doping, biasing and introducing highly doped pixel boundary trenches on response resolution undertaken. Additionally, for the former pixel, the effect of introducing a guard-ring electrode on its electrical response resolution is investigated. For single junction photodiode pixels, the boundary trench isolation, a highly doped recombination boundary trench placed either side of each pixel\u27s well, showed considerably less pixel response resolution and hence more crosstalk than using the guard-ring electrode configuration. However the boundary-trench-isolation-pixel\u27s response was an improvement on the unguarded single junction photodiode pixel\u27s response. The outer junction of the double junction photodiode pixel acts in the same way as the guard-ring electrode for the single junction photodiode pixel, by suppressing the pixel response away from the pixel centre. However for pixels with similar geometry of outer well and substrate to the single junction photodiode guarded pixel, the outer junction guard improves the pixel response resolution more than the electrode guard does. However for shallow pixels their response resolutions are not significantly different, in that response outside the well (outer well in double junction photodiode pixels) is insignificant. The response resolution is more flexibly varied inside this well for the double junction than for the guarded single junction photodiode pixel. Generally the frontside illuminated photodiode pixels have better response resolution and hence crosstalk suppression than the same pixel backside illuminated. This is due primarily to their greater depletion region absorption volume proportion. This results from the closer proximity of their photogenerated carrier-envelope to their pixel\u27s depletion region. However as frontside and backside illuminated pixel absorption volume proportions converge, their response resolution becomes less distinguishable. The predictive advantage of pixel absorption volume data for optimal pixel response resolution is evident. Such data can help to narrow the selection of possible optimal pixel configurations. However simulation is still the necessary final arbiter without the more costly fabricated-device testing option available

The Gap Between Professional Competencies of Occupational Safety and Health Representatives in China and Western Australia

This paper examines the role and education of Occupational Safety and Health Representatives in China in comparison with those in Western Australia. It reports on the link between WorkSafe Western Australia and China and how this link can benefit occupational safety and health representatives and their effectiveness in China

Double Boundary Trench Isolation Effects on a Stacked Gradient Homojunction Photodiode Array

The effect of the width of inter-pixel double boundary trench isolation on the response resolution of a two dimensional CMOS compatible stacked gradient homojunction photodiode array was simulated. Insulation and P-doped double boundary trench isolation were compared. Both geometries showed improved crosstalk suppression and enhanced sensitivity compared to photodiode geometries previously investigated, combined with a reduction in fabrication complexity for the insulation DBTI configuration

Guard-Ring Electrode Effects on Crosstalk in Simulated 2D CMOS Compatible Vertical Photodiode Pixel Arrays

In this study, we have simulated the electrical crosstalk in back-illuminated and front-illuminated photodiode arrays as a function of substrate thickness and junction depth for single junction photodiode pixels, with and without guard-ring electrodes. The physical mechanisms responsible for electrical crosstalk suppression are explained using an absorption volume proportion concept. The results obtained show that significant crosstalk suppression can be achieved for back-illuminated thin substrate guarded-pixel array

Effect of COVID-19 Pandemic on Traditional Teaching

COVID 19 made a great impact on education system especially on the university education system globally. The purpose of this systematic review of published literature was to trace the history of university teaching and examine the effects of the COVID 19 pandemic on traditional teaching. Systematic review started with 720 articles and ended with the inclusion of 136 articles based on bibliometric search process. Important understandings generated are that educational methods are constantly evolving as what the ruling society values changes and when new technologies that can be used for teaching are invented. Conclusions were that this deadly pandemic overturned the traditional offline teaching and learning process and facilitated the introduction of emergency online educational platforms to be used for university teaching and student learning