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We experimentally investigated the asymmetric dual-grating-gate plasmonic terahertz (THz) detector based on an InGaAs-channel high-electron-mobility transistor (HEMT) in the gate-readout configuration. Throughout the THz pulse detection measurement on the fabricated device, we discovered a new detection mechanism called the “3D rectification effect” at the positive gate bias application, which is a cooperative effect of the plasmonic nonlinearities in the channel with the diode nonlinearity in the heterobarrier between the InGaAs channel layer and the InAlAs spacer/carrier-supply/barrier layers, resulting in a giant enhancement of the detector responsivity. We also found that an undesired long-tail waveform observed on the temporal pulse photoresponse of the device is due to trapping of carriers to the donor levels in the silicon δ-doped carrier-supply layer when they tunnel through the barrier to the gate and can be eliminated completely by introducing the so-called inverted-HEMT structure. The internal current responsivity and noise-equivalent power are estimated to be 0.49 A/W (with the equivalent voltage responsivity of 4.9 kV/W with a high output impedance of 10 kΩ) and 196 pW/√Hz at 0.8 THz. These results pave the way towards the application of the plasmonic THz detectors to beyond-5G THz wireless communication systems.

Over 1.7 billion students around the world have had their education disrupted by the spread of the Coronavirus disease worldwide. Schools and universities have not faced this level of disruption since World War II. The COVID-19 pandemic presented a colossal challenge for teachers to urgently and massively adapt all their classes to distance learning in order to maintain educational continuity with the same quality. Even if some teachers and certain classes were ready to face the situation, a large majority had to adapt their teaching and learning in a very short time without training, with insufficient bandwidth, and with little preparation. This unexpected and rapid transition to online learning has led to a multiplication of teachers' strategies for distance learning in lectures, tutorials, project groups, lab works, and assessments. The purpose of this paper is to present the feedback from students and teachers who participated in the lockdown semester of two different groups of a 5-year program in Chemistry, Environment and Chemical Engineering (100 students) at INSA Toulouse (France). The analysis has highlighted some great successes and some failures in the solutions proposed. Consequently, some guidelines can be given to help us all to learn the lessons of such a singular experience in order to face the unexpected future with more knowledge and more successful distance learning. Teachers have shown very strong resilience during this crisis, at the cost of significant personal commitment. They admit that they have learned more about distance education in two months than in the last 10 years.

This article analyzes the closure of the Superphénix fast breeder plant in Creys-Malville, decided in 1997 after 11 years of operation. The Superphénix plant is the only case of a complete closure of a full-scale nuclear power plant in France. It provides information on post-closure territorial trajectories in areas where the nuclear power industry provided many well-paid jobs and significant local tax revenues. In order to document the territorial transformations following the closure, we look into mobilities, based on two sources of data: on the one hand, a quantitative study of residential and professional mobilities that uses the population census (1990, 1999, 2012) and allows us to show the transformation of the employment area around Creys-Malville and the evolution of the socio-economic polarization of the territory; on the other hand, a qualitative study of thirty-one interviews conducted during a field survey in 2012 with territorial actors (residents, mayors, industrialists), which allow us to relate the effects of the closure and the induced mobilities to actors' statements. The article shows how the effects of territorial dereliction feared by the opponents of the closure did not occur: the closure of the site was compensated by new residential and professional mobilities, made possible in particular by the development of the industrial zone of the Ain plain east of Lyon.

To develop a 14-winter (October–April; 1999–2013) climatic description of polar low (PL) occurrence for the Nordic Seas, systems have been tracked using images acquired from the Very High Resolution Radiometer (AVHRR). Also, the dominant PL characteristics – their temporal and spatial distributions, size, lifespan, distance travelled, speed of propagation and directions – have been determined. On average, 14 PL events occur per winter but there is strong inter-annual and intra-seasonal variability. Although systems may form and travel over the whole Nordic Seas, their genesis is enhanced in areas characterised by warm oceanic currents. At the start of the season (October–November), systems mainly form over the Greenland and Norwegian Seas, but further into winter they form increasingly over the Barents Sea. In connection with recent low-ice winters, new areas of PL formation are evident, particularly to the west of Spitsbergen and in the Barents Sea. PL speeds of propagation range between 5 and 13 m/s but are observed to be highly variable among cases and even during the lifespan of individual PLs. To a considerable extent, the direction of movement is controlled by the large-scale flow in the lowest atmospheric layers, but we also observed cyclonic co-rotation of some pairs of PLs due to their influence on the ambient flow. Although these generally move southward or southeastward, a substantial number of PLs have westward and even northward tracks. PLs in the western part of the region average larger than their eastern counterparts. This study also highlights that PLs characteristics and tracks differ according to weather regimes.