Biomass burning impacts vegetation dynamics, biogeochemical cycling, atmospheric chemistry, and climate, with sometimes deleterious socio-economic impacts. Under future climate projections it is ...often expected that the risk of wildfires will increase. Our ability to predict the magnitude and geographic pattern of future fire impacts rests on our ability to model fire regimes, using either well-founded empirical relationships or process-based models with good predictive skill. While a large variety of models exist today, it is still unclear which type of model or degree of complexity is required to model fire adequately at regional to global scales. This is the central question underpinning the creation of the Fire Model Intercomparison Project (FireMIP), an international initiative to compare and evaluate existing global fire models against benchmark data sets for present-day and historical conditions. In this paper we review how fires have been represented in fire-enabled dynamic global vegetation models (DGVMs) and give an overview of the current state of the art in fire-regime modelling. We indicate which challenges still remain in global fire modelling and stress the need for a comprehensive model evaluation and outline what lessons may be learned from FireMIP.
We report the direct measurement of antiferromagnetic spin polarization at the oxygen sites in the multiferroic TbMn2O5, through resonant soft x-ray magnetic scattering. This supports recent ...theoretical models suggesting that the oxygen spin polarization is key to the magnetoelectric coupling mechanism. The spin polarization is observed through a resonantly enhanced diffraction signal at the oxygen K edge at the commensurate antiferromagnetic wave vector. Using the fdmnes code we have accurately reproduced the experimental data. We have established that the resonance arises through the spin polarization on the oxygen sites hybridized with the square based pyramid Mn3+ ions. Furthermore we have discovered that the position of the Mn3+ ion directly influences the oxygen spin polarization.
An organic electrophosphorescent white‐light‐emitting device (see Figure) containing green, red, and blue emitters doped into a 9 nm thick wide‐bandgap material is shown to attain a maximum forward ...viewing power efficiency of (26±3) lm W–1. The high power efficiency is attributed to the efficient confinement of excitons and charge within the emissive layer, a thin emissive layer, and highly efficient blue electrophosphorescent dopant.
We review recent results in the field of organic light-emitting devices (OLED's), with particular attention to the application of organic light-emitting devices to ultra-lightweight, full color, ...flat-panel displays. We show that OLED brightness, efficiency, operating voltage, and lifetime is sufficient to compete with other flat-panel display technologies such as backlit liquid crystal displays. We describe a novel, tunable OLED consisting of vertically stacked, transparent light-emitting devices which can serve as a color-tunable element in high-resolution full-color display., In addition, the unique physical properties of organic thin films allow for flexible, conformable, or foldable displays which are unobtainable with conventional, inorganic semiconductor technologies.
Thin films of many molecular materials are considered `amorphous' because they possess no detectable long-range order. However, we show that the fluorescence spectrum of polar molecules may shift due ...to the formation of ordered polar domains within an otherwise amorphous film. A model is derived to explain this shift and the associated quenching of luminescence as domains are formed. We demonstrate that the inclusion of dipole–dipole intermolecular correlations has a significant effect on calculations of the electronic properties of organic amorphous thin films.
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