Experimental performance evaluation of quadrature amplitude modulation signal transmission in a silicon microring

We comprehensively characterize the transmission performance of m-ary quadrature amplitude modulation(m-QAM) signals through a silicon microring resonator in the experiment. Using orthogonal frequency-division multiplexing based on offset QAM(OFDM/OQAM) which is modulated with m-QAM modulations, we demonstrate low-penalty data transmission of OFDM/OQAM 64-QAM, 128-QAM, 256-QAM, and 512-QAM signals in a silicon microring resonator. The observed optical signal-to-noise ratio(OSNR) penalties are 1.7 dB for 64-QAM,1.7 dB for 128-QAM, and 3.1 dB for 256-QAM at a bit-error rate(BER) of 2 × 10^(-3) and 3.3 dB for 512-QAM at a BER of 2 × 10^(-2). The performance degradation due to the wavelength detuning from the microring resonance is evaluated, showing a wavelength range of ~0.48 nm with BER below 2 × 10^(-3). Moreover, we demonstrate data transmission of 191.2-Gbit/s simultaneous eight wavelength channel OFDM/OQAM 256-QAM signals in a silicon microring resonator, achieving OSNR penalties less than 2 dB at a BER of 2 × 10^(-2).

Theoretical analysis and experimental research on non-cavitation noise modulation mechanism of underwater counter-rotation propeller

The underwater counter-rotation propeller non-cavitation noise has an obvious mod- ulation characteristic which is due to the interaction of flow and blade. A modulation mecha- nism is presented in this paper. A sound pressure spectrum model is presented to describe its non-cavitation noise with application of generalized acoustic analogy method, the modulation mechanism is expressed with the improvement of sound pressure model. The power spectrum and modulation spectrum are presented by numerical simulation. Theoretical analysis and nu- merical simulation results are verified by the cavitation tunnel experiment. The modulation model of counter-rotation propeller is beneficial to the prediction modulation characteristics and identification of underwater high-speed vehicles.

Emergency Housing Solutions after Earthquakes:Innovative Technologies and Resilience Strategies

The international research project,developed through the collaboration between the University of Chieti and Pescara“G.d'Annunzio”and theÉcole Nationale d'Architecture of Marrakech,aims to explore new strategies for emergency housing,with a focus on technological innovation and the resilience of temporary shelters.The main goal of the research is to define a more efficient housing module for post-earthquake scenarios,based on the analysis of the most advanced international solutions for first-response shelters.This study has made it possible to identify both the strengths and weaknesses of existing proposals,leading to the development of a housing model capable of improving living conditions during emergency phases.The objective is to propose an innovative housing module that not only addresses immediate post-disaster needs but is also adaptable to the specific socio-cultural characteristics of the affected populations.As a result of this work,the“DIVA-Variable Dimension Emergency Shelter”project was developed.This housing model stands out for its ability to adapt to the needs of different emergency phases,offering a versatile and customizable solution that effectively addresses post-earthquake challenges while ensuring respect for cultural specificities and improving quality of life.