Determination of the effects of liquid injectants on nozzle ablative performance Final report

Evaluating effect of liquid fuel injectants on ablative performance of low cost nozzle material

Turbo-code division multiple access: capacity enhancement of mobile satellite systems using narrowband multiuser detection

This paper presents a new type of multiple access for fixed and mobile satellite communication systems aiming at improving the bandwidth efficiency of highly reliable links suited for air traffic management and other safety services, using compact and low cost terminals. The purpose of this work is to incorporate highly redundant turbo coding technology in the air interface and present a novel receiver architecture using narrowband multiuser detection to enhance the performance of the reservation access and random access signaling

Influence of noise on Josephson junctions dynamics with a BCS theory-based model

We developed a weak-linked Josephson junction time-domain simulation tool based on the Bardeen-Cooper-Schrieffer (BCS) theory to account for the electrodynamics of Cooper pairs and quasiparticles in the presence of thermal noise. The model, based on Werthamer and Harris formalisms, allows us to describe the behavior of Josephson junctions for various current and/or voltage input waveforms, analog or digital, and for any operating temperature below the critical temperature of the superconducting materials. We show a good agreement between experimental and simulated IV curves of Josephson junctions, as well as a relative increase of the grey zone width of an SFQ balanced comparator between 4 and 20% due to the presence of quasiparticles, for McCumber parameters comprised between 0.1 and 1, respectively.Comment: Presented at the European Conference on Applied Superconductivity (EUCAS 2023), Bologna, Italy, 03-07 September 2023. 5 pages, 6 figures, 21 reference

Signal processing techniques for aeronautical communications via satellite

Aeronautical communications are playing an important role in the air traffic control as well as new passenger communication services. Due to the global coverage required, satellite transponders provide the required links which are traditionally limited to narrowband throughputs (e.g. 64 kb/s) due to the propagation channel characteristics. This paper analyses the reasons that limit the throughput of the aeronautical satellite links and presents advanced signal processing techniques that allow satellite transceivers to break the narrowband barriers

Josephson oscillation linewidth of ion-irradiated YBa2_2Cu3_3O7_7 junctions

We report on the noise properties of ion-irradiated YBa$_2$Cu$_3$O$_7$ Josephson junctions. This work aims at investigating the linewidth of the Josephson oscillation with a detector response experiment at $\simeq$132 GHz. Experimental results are compared with a simple analytical model based on the Likharev-Semenov equation and the de Gennes dirty limit approximation. We show that the main source of low-frequency fluctuations in these junctions is the broadband Johnson noise and that the excess ($\frac{1}{f}$) noise contribution does not prevail in the temperature range of interest, as reported in some other types of high-T$_c$ superconducting Josephson junctions. Finally, we discuss the interest of ion-irradiated junctions to implement frequency-tunable oscillators consisting of synchronized arrays of Josephson junctions