STRUCTURAL MODEL OF ORGANIZATIONAL BEHAVIOR

В студията се разглежда взаимодействието между управленски процеси, структура и цели. Характерът на това взаимодействие се определя от степента на взаимозависимост между изпълняваните управленски дейности и тяхната сложност. Отстоява се схващането, че доброто познаване на управленските процеси и дейности в организацията е предпоставка за тяхното оптимизиране. Представя се концептуална управленска рамка, която дава възможност да се разкрие степента на взаимодействие между различните управленски отдели и звена в процеса на осъществяване на поставените стратегически цели. Изследва се въздействието на редица вътрешни и външни фактори при вземане на управленски решения и формирането на оптимално организационно поведение. The study examines the interaction between managerial processes, structure and goals. The nature of this interaction is conditioned upon the level of interdependence between various managerial activities and their level of complexity. The argument is that the level of managerial comprehension of organizational processes and activities is a preconditioning factor optimizing organizational performance. In addition, the study introduces a conceptual framework the helps reveal the nature of interdependence between the examined managerial units in the implementation stage of the planned strategic goals. A number of environmental factors are put into perspective in the light of strategic decision-making and organizational behavior optimization

Ultra-ductile and low friction epoxy matrix composites

We present the results of an effective reinforcement of epoxy resin matrix with fullerene carbon soot. The optimal carbon soot addition of 1 wt. % results in a toughness improvement of almost 20 times. The optimized soot-epoxy composites also show an increase in tensile elongation of more than 13 %, thus indicating a change of the failure mechanism in tension from brittle to ductile. Additionally, the coefficient of friction is reduced from its 0.91 value in plain epoxy resin to 0.15 in the optimized composite. In the optimized composite, the lateral forces during nanoscratching decrease as much as 80 % with enhancement of the elastic modulus and hardness by 43 % and 94%, respectively. The optimized epoxy resin fullerene soot composite can be a strong candidate for coating applications where toughness, low friction, ductility and light weight are important.Comment: 24 pages, 7 Figures, 1 Table in Polymer Testing (2015

Idealizing Tauc Plot for Accurate Bandgap Determination of Semiconductor with UV-Vis: A Case Study for Cubic Boron Arsenide

The Tauc plot method is widely used to determine the bandgap of semiconductors via UV-visible optical spectroscopy due to its simplicity and perceived accuracy. However, the actual Tauc plot often exhibits significant baseline absorption below the expected bandgap, leading to discrepancies in the calculated bandgap depending on whether the linear fit is extrapolated to zero or non-zero baseline. In this study, we show that both extrapolation methods can produce significant errors by simulating Tauc plots with varying levels of baseline absorption. To address this issue, we propose a new method that involves idealizing the absorption spectrum by removing its baseline before constructing the Tauc plot. Experimental verification of this method using a gallium phosphide (GaP) wafer with intentionally introduced baseline absorptions shows promising results. Furthermore, we apply this new method to cubic boron arsenide (c-BAs) and resolve discrepancies in c-BAs bandgap values reported by different groups, obtaining a converging bandgap of 1.835 eV based on both previous and new transmission spectra. The method is applicable to both indirect and direct bandgap semiconductors, regardless of whether the absorption spectrum is measured via transmission or diffuse reflectance, will become essential to obtain accurate values of their bandgaps

Theory and Experiments of Pressure-Tunable Broadband Light Emission from Self-Trapped Excitons in Metal Halide Crystals

Hydrostatic pressure has been commonly applied to tune broadband light emissions from self-trapped excitons (STE) in perovskites for producing white light and study of basic electron-phonon interactions. However, a general theory is still lacking to understand pressure-driven evolution of STE emissions. In this work we first identify a theoretical model that predicts the effect of hydrostatic pressure on STE emission spectrum, we then report the observation of extremely broadband photoluminescence emission and its wide pressure spectral tuning in 2D indirect bandgap CsPb2Br5 crystals. An excellent agreement is found between the theory and experiment on the peculiar experimental observation of STE emission with a nearly constant spectral bandwidth but linearly increasing energy with pressure below 2 GPa. Further analysis by the theory and experiment under higher pressure reveals that two types of STE are involved and respond differently to external pressure. We subsequently survey published STE emissions and discovered that most of them show a spectral blue-shift under pressure, as predicted by the theory. The identification of an appropriate theoretical model and its application to STE emission through the coordinate configuration diagram paves the way for engineering the STE emission and basic understanding of electron-phonon interaction