Ultrafast valley relaxation dynamics in monolayer MoS2 probed by nonequilibrium optical techniques

We study the exciton valley relaxation dynamics in single-layer MoS2 by a combination of two nonequilibrium optical techniques: time-resolved Faraday rotation and time-resolved circular dichroism. The depolarization dynamics, measured at 77 K, exhibits a peculiar biexponential decay, characterized by two distinct time scales of 200 fs and 5 ps. The fast relaxation of the valley polarization is in good agreement with a model including the intervalley electron-hole Coulomb exchange as the dominating mechanism. The valley relaxation dynamics is further investigated as a function of temperature and photoinduced exciton density. We measure a strong exciton density dependence of the transient Faraday rotation signal. This indicates the key role of exciton-exciton interactions in MoS2 valley relaxation dynamics

Scrivere in guerra. I notai negli eserciti dell\u2019Italia comunale (secoli XII-XIV)

Within the tradition of Diplomatic studies, since the most ancient contributions concerned with the history of documentation produced by central northern Italy cities, it is possible to point out that very little attention has been paid to the presence of the notaries and to the role of their deeds during military expeditions. The work here proposed aims, first of all, at conducting research into the roles played by the notaries within military organization, marking how they constantly worked together with capitani, costringitori and consiglieri of cities\u2019 armies and saw about the regular registration of the shirkers, of the weapons, of foodstuffs sold to the troops. The second part of this paper will investigate in detail how the registrations were done: we\u2019ll try to put in evidence the connexions between the forms and the functions of a kind of documentation surely \u2018non-typical\u2019, but that seems to represent a further, interesting point of view for observing a side until almost unknown of the so called \u201cdocumentary revolution\u201d and the topos of notarial omnipresence in Middle Ages Italy

Longitudinal insulation performance of HV circuit-breakers under the joint effect of pollution and temporary overvoltages

SIGLEITItal

Encapsulation of Photosystem i in Organic Microparticles Increases Its Photochemical Activity and Stability for Ex Vivo Photocatalysis

Photosystem I (PSI) is a pigment binding multisubunit protein complex involved in the light phase of photosynthesis, catalyzing a light-dependent electron transfer reaction from plastocyanin to ferredoxin. PSI is characterized by a photochemical efficiency close to one, suggesting its possible application in light-dependent redox reaction in an extracellular context. The stability of PSI complexes isolated from plant cells is however limited if not embedded in a protective environment. Here we show an innovative solution for exploiting the photochemical properties of PSI, by encapsulation of isolated PSI complexes in PLGA (poly lactic-co-glycolic acid) organic microparticles. These encapsulated PSI complexes were able to catalyze light-dependent redox reactions with electron acceptors and donors outside the PLGA microparticles. Moreover, PSI complexes encapsulated in PLGA microparticles were characterized by a higher photochemical activity and stability compared with PSI complexes in detergent solution, suggesting their possible application for ex vivo photocatalysis

Non-invasive optical diagnosis of gases in wood

Non-invasive optical diagnosis of gases in woo