Size scaling of the addition spectra in silicon quantum dots

We investigate small artificial quantum dots obtained by geometrically controlled resistive confinement in low mobility silicon-on-insulator nanowires. Addition spectra were recorded at low temperature for various dot areas fixed by lithography. We compare the standard deviation of the addition spectra with theory in the high electron concentration regime. We find that the standard deviation scales as the inverse area of the dot and its absolute value is comparable to the energy spacing of the one particle spectrum.Comment: 4 pages, 5 figure

Developpement d'un système de dopage "PM" : premiers essais

National audienceThe participation to inter-laboratory exercises is a key step for any ambient air quality monitoring network. To guarantee the interest of such campaigns, participants need a large range of concentration, including regulatory limits. As far as PM10 is concerned, the 1996 European directive implement a 24h hours limit of 50 micro g/m3 with a maximum relative uncertainty of 25%. In the frame of the French National Air Quality Laboratory (LCSQA), INERIS -in relation with LNI Inc.- is developing a special PM generator. The objective is to distribute to all participants an ambient air enriched with PM10 or PM2,5 particles. Preliminary results show that our prototype is able to distribute to 4 TEOM and TEOM-FDMS microbalances air in a range from the background up to 100 micro g/m3 and more. The set-up and the results will be presented.La reconnaissance d'une compétence en matière de mesurage passe par la participation à des exercices d'intercomparaison, ou " exercices inter-laboratoires ". Ce type d'exercice est organisé dans le cadre de la surveillance réglementaire " air ambiant " française. Afin de garantir l'efficacité d'une telle session, il est essentiel de bénéficier d'un spectre large de concentration, et tout particulièrement d'inclure les valeurs limites pour lesquelles il existe des exigences en matière d'incertitude. C'est le cas de la surveillance des PM10, pour lesquels une incertitude maximale de 25% est exigée à 50 micro g/m3 (mesure journalière). Il est en pratique impossible de garantir a priori un tel niveau de concentration. C'est pourquoi dans le cadre du LCSQA, l'INERIS a entrepris de développer des systèmes d'enrichissement, appelés aussi " systèmes de dopage ". La présente communication est consacrée au développement d'un tel dispositif pour les particules de type PM10 et PM 2,5. Les objectifs, le montage expérimental, ainsi que les premiers résultats, seront rapportés dans le cas de microbalances TEOM et TEOM-FDMS, pour des concentrations allant du niveau de fond à plus de 100 micro g/m3. Une attention particulière sera portée sur les contraintes et les résultats obtenus en matière de représentativité de la matrice, ainsi qu'en matière d'équivalence des échantillons fournis à chaque analyseur participant

Self-consumption of electricity from renewable sources

If the cost of energy production from renewable energy sources (RES) reduces below the level of electricity retail prices, self-consumption (SC) can contribute to market integration of RES. Support schemes such as feed-in tariffs could be phased out in view of parity of retail prices and RES production costs. In combination with electricity storage and demand response (DR), SC can facilitate the integration of variable renewables onto the grid and lower the overall costs of the energy system through load shifting particularly if storage and DR is managed using ICT and algorithms controlling charging cycles and usage of electric devices. Some issues remain however: Self-consumption potential is limited without further technical enhancements in storage or DR solutions. To organize self-consumption efficiently, measures on the grid side and energy storage have to be taken. Enabling the grid to provide necessary information back to prosumers and vice versa, as well as developing economic ways of storing energy is key to unleashing the potential that lies within the transition from passive consumers to active prosumers. Different policies, such as the support of investments to storage installations, can foster those developments. The impact of electricity retail prices has to be considered also. Self-consumption is profitable if the costs of locally produced RES are lower than the retail electricity price. There are, however, worries that a high penetration of self-consumption solutions might lead to an unfair distribution of network charges, taxes and levies even if storage and DR measures can lower additional costs arising from PV integration. Future energy policy can address the way how costs get allocated

Contextualising adverse events of special interest to characterise the baseline incidence rates in 24 million patients with COVID-19 across 26 databases: a multinational retrospective cohort study

BACKGROUND: Adverse events of special interest (AESIs) were pre-specified to be monitored for the COVID-19 vaccines. Some AESIs are not only associated with the vaccines, but with COVID-19. Our aim was to characterise the incidence rates of AESIs following SARS-CoV-2 infection in patients and compare these to historical rates in the general population. METHODS: A multi-national cohort study with data from primary care, electronic health records, and insurance claims mapped to a common data model. This study's evidence was collected between Jan 1, 2017 and the conclusion of each database (which ranged from Jul 2020 to May 2022). The 16 pre-specified prevalent AESIs were: acute myocardial infarction, anaphylaxis, appendicitis, Bell's palsy, deep vein thrombosis, disseminated intravascular coagulation, encephalomyelitis, Guillain- Barré syndrome, haemorrhagic stroke, non-haemorrhagic stroke, immune thrombocytopenia, myocarditis/pericarditis, narcolepsy, pulmonary embolism, transverse myelitis, and thrombosis with thrombocytopenia. Age-sex standardised incidence rate ratios (SIR) were estimated to compare post-COVID-19 to pre-pandemic rates in each of the databases. FINDINGS: Substantial heterogeneity by age was seen for AESI rates, with some clearly increasing with age but others following the opposite trend. Similarly, differences were also observed across databases for same health outcome and age-sex strata. All studied AESIs appeared consistently more common in the post-COVID-19 compared to the historical cohorts, with related meta-analytic SIRs ranging from 1.32 (1.05 to 1.66) for narcolepsy to 11.70 (10.10 to 13.70) for pulmonary embolism. INTERPRETATION: Our findings suggest all AESIs are more common after COVID-19 than in the general population. Thromboembolic events were particularly common, and over 10-fold more so. More research is needed to contextualise post-COVID-19 complications in the longer term. FUNDING: None

Model for screening of resonant magnetic perturbations by plasma in a realistic tokamak geometry and its impact on divertor strike points

This work addresses the question of the relation between strike-point splitting and magnetic stochasticity at the edge of a poloidally diverted tokamak in the presence of externally imposed magnetic perturbations. More specifically, ad-hoc helical current sheets are introduced in order to mimic a hypothetical screening of the external resonant magnetic perturbations by the plasma. These current sheets, which suppress magnetic islands, are found to reduce the amount of splitting expected at the target, which suggests that screening effects should be observable experimentally. Multiple screening current sheets reinforce each other, i.e. less current relative to the case of only one current sheet is required to screen the perturbation.Comment: Accepted in the Proceedings of the 19th International Conference on Plasma Surface Interactions, to be published in Journal of Nuclear Materials. Version 2: minor formatting and text improvements, more results mentioned in the conclusion and abstrac

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Method for making a wire nanostructure in a semiconductor film

This invention relates to a process for manufacturing nanowire structures, the process comprising the following steps:manufacture of a thin semiconductor film (1) extending between a first terminal (4) and a second terminal (5), andpassage of a current between the first and the second terminals so as to form at least one continuous overthickness (R1, R2, R3) in the thin semiconductor film by migration of a fraction of the semiconductor material, under the action of the current, the continuous overthickness being formed along the direction of the current that passes through the film