Elastic behavior in Contact Dynamics of rigid particles

The systematic errors due to the practical implementation of the Contact Dynamics method for simulation of dense granular media are examined. It is shown that, using the usual iterative solver to simulate a chain of rigid particles, effective elasticity and sound propagation with a finite velocity occur. The characteristics of these phenomena are investigated analytically and numerically in order to assess the limits of applicability of this simulation method and to compare it with soft particle molecular dynamics.Comment: submitted to PRE, 7 pages, 6 figure

SKIM, a candidate satellite mission exploring global ocean currents and waves

The Sea surface KInematics Multiscale monitoring (SKIM) satellite mission is designed to explore ocean surface current and waves. This includes tropical currents, notably the poorly known patterns of divergence and their impact on the ocean heat budget, and monitoring of the emerging Arctic up to 82.5°N. SKIM will also make unprecedented direct measurements of strong currents, from boundary currents to the Antarctic circumpolar current, and their interaction with ocean waves with expected impacts on air-sea fluxes and extreme waves. For the first time, SKIM will directly measure the ocean surface current vector from space. The main instrument on SKIM is a Ka-band conically scanning, multi-beam Doppler radar altimeter/wave scatterometer that includes a state-of-the-art nadir beam comparable to the Poseidon-4 instrument on Sentinel 6. The well proven Doppler pulse-pair technique will give a surface drift velocity representative of the top meter of the ocean, after subtracting a large wave-induced contribution. Horizontal velocity components will be obtained with an accuracy better than 7 cm/s for horizontal wavelengths larger than 80 km and time resolutions larger than 15 days, with a mean revisit time of 4 days for of 99% of the global oceans. This will provide unique and innovative measurements that will further our understanding of the transports in the upper ocean layer, permanently distributing heat, carbon, plankton, and plastics. SKIM will also benefit from co-located measurements of water vapor, rain rate, sea ice concentration, and wind vectors provided by the European operational satellite MetOp-SG(B), allowing many joint analyses. SKIM is one of the two candidate satellite missions under development for ESA Earth Explorer 9. The other candidate is the Far infrared Radiation Understanding and Monitoring (FORUM). The final selection will be announced by September 2019, for a launch in the coming decade

Comparison between recoverable and permanent NBTI variability components

session 8: Large StatisticsInternational audienceIn this paper, we present a statistical analysis of recoverable and permanent NBTI components. Measurements are performed on PFET devices issued from ST Microelectronics 28nm FDSOI technology, covering a wide range of device dimensions W and L. We analyzed NBTI degradation and recovery measured at μs time scale, resulting from AC and DC stress. We were able to confront VTh drift variability during stress and relaxation phase and evidence significant differences of variability between stress and relaxation phase

New perspectives in defect centric model for NBTI reliability

International audienc

New NBTI models for degradation and relaxation kinetics valid over extended temperature and stress/recovery ranges

International audienceIn this paper we present NBTI stress and recovery effects measured on PFET devices issued from various FDSOI technologies. NBTI degradation and recovery subsequent to DC stress are measured at the μs time scale. After in-depth analysis of temperature and stress/recovery bias effects, we propose new NBTI models for degradation and recovery kinetics including temperature, Vgstress and Vgrecovery dependencies. These models are finally validated on different technologies and various experimental conditions

Characterization and modeling of NBTI permanent and recoverable components variability

session posterInternational audienceIn this paper we use a statistical analysis of NBTI stress and recoverable components measured on Pfet devices issued from ST Microelectronics 28nm FDSOI technology. NBTI degradation and recovery resulting from AC and DC stress are measured at μs time scale. Statistical analysis of the permanent and recoverable components are performed separately. A Dual Defect Centric Model (DDCM) accounting for these two components is also proposed

On the cumulative distribution function of the defect centric model for BTI reliability

International audienceThe validity of the existing cumulative distribution function (CDF) formulas for the defect centric model (DCM) is discussed, especially in the low defect number regime (defect number < 3). After finding their limitations, we propose an improved DCM CDF formula which well accounts for the low defect number regime, becoming important in advanced CMOS technologies with scaled devices. The benefits of the revisited DCM CDF formula are experimentally demonstrated on pMOS devices from 28 nm FDSOI technology subjected to BTI stress as well as on Monte Carlo simulated Vth data

Improved analysis of NBTI relaxation behavior based on fast I–V measurement

session posterInternational audienceIn this paper, we propose a qualitative analysis of NBTI recoverable components measured on pFET devices issued from various ST Microelectronics (28nm FDSOI technology and 40nm SION or Bulk) technologies. NBTI degradation and recovery resulting from DC stress are measured at μs time scale. We observed similarities between temperature and Vg recovery dependencies on NBTI relaxation of SiON and FDSOI technologies. Then, we discuss the nature of one defect type responsible for the NBTI at early stage of relaxation

Role of particle – particle contacts in the thermophysical behaviour of green bodies during drying and firing

International audienc