Inhibited spontaneous emission of quantum dots observed in a 3D photonic band gap

We present time-resolved emission experiments of semiconductor quantum dots in silicon 3D inverse-woodpile photonic band gap crystals. A systematic study is made of crystals with a range of pore radii to tune the band gap relative to the emission frequency. The decay rates averaged over all dipole orientations are inhibited by a factor of 10 in the photonic band gap and enhanced up to 2? outside the gap, in agreement with theory. We discuss the effects of spatial inhomogeneity, nonradiative decay, and transition dipole orientations on the observed inhibition in the band gap.Comment: 5 figures, update author lis

Investigation on polycarbonate nanomembrane production based on alpha particles irradiation

Track-etched membranes were prepared in the Dosimetry Laboratory of Agricultural, Medical and Industrial Research School by exposing polycarbonate (PC) films with a thickness of about 20 μm to alpha particles emitted from 241Am followed by chemical etching in sodium hydroxide (NaOH) at different temperatures and solution concentrations. The PC films were prepared using the method of chemical solving, forming and drying in a vacuum oven. The etching rate of PC was related to the concentration of etching solution, etching temperature and time. Therefore, a series of track-etched membranes were produced using different etching parameters. The relation between the etching rate and the etching parameters were established from experimental data and can be used to control the average pore sizes of the PC track-etched membrane. The pore sizes and their structures were studied by an optical microscope (OM) and a scanning electron microscope (SEM) and the obtained results indicated that the pores across the PC films are cylindrically shaped

Big Data and Energy Security: Impacts on Private Companies, National Economies and Societies

The importance of energy security for the successful functioning of private companies, national economies, and the overall society cannot be underestimated. Energy is a critical infrastructure for any modern society, and its reliable functioning is essential for all economic sectors and for the well-being of everybody. Uncertainty in terms of the availability of information, namely reliable data to make predictions and to plan for investment as well as for other actions of stakeholders in the energy markets is one of the factors with the highest influence on energy security. This uncertainty can be connected with many factors, such as the availability of reliable data or actions of stakeholders themselves. For example, the recent outbreak of the COVID-19 pandemic revealed negative impacts of uncertainty on decision-making processes and markets. At the time point when the market participants started to receive real-time information about the situation, the energy markets began to ease. This is one scenario where Big Data can be used to amplify information to various stakeholders to prevent panic and to ensure market stability and security of supply. Considering the novelty of this topic, our methodology is based on the meta-analysis of existing studies in the area of impacts of energy security on private companies, the national economy, and society. The results show that, in a fast-paced digital world characterized by technological advances, the use of Big Data technology provides a unique niche point to close this gap in information disparity by levering the use of unconventional data sources to integrate technologies, stakeholders, and markets to promote energy security and market stability. The potential of Big Data technology is yet to be fully utilized. Big Data can handle large data sets characterized by volume, variety, velocity, value, and complexity. Our conclusion is that the challenge for energy markets is to leverage this technology to mine available socioeconomic, political, geographic, and environmental data responsibly and to provide indicators that predict future global supply and demand. This information is crucial for energy security and ensuring global economic prosperit