Oxide dispersion strengthened (ODS) ferritic steels are considered promising candidates as cladding tubes for Generation IV nuclear reactors. In such reactors, irradiation damage can reach more than 150 dpa at temperatures ranging from 400 to 650 °C. Thus nanoparticle stability has to be guaranteed in order to ensure that these materials possess excellent creep properties. Using Fe ions, ODS steels were irradiated at 500 °C up to 150 dpa. At this temperature the nano-oxide population evolution under irradiation is similar to that observed after annealing at high temperature. It consists of a slight increase in the particle size and a slight decrease in the density, which can be both explained by an Ostwald ripening mechanism. Conversely, irradiations performed at room temperature using Au ions lead to a complete dissolution of the oxide particles, in agreement with the estimation of ballistic vs. radiation enhanced diffusion effects

Abstract. The IPCC has stressed the importance of producing unbiased estimates of the uncertainty in indirect aerosol forcing, in order to give policy makers as well as research managers an understanding of the most important aspects of climate change that require refinement. In this study, we use 3-D meteorological fields together with a radiative transfer model to examine the spatially-resolved uncertainty in estimates of the first indirect aerosol forcing. The global mean forcing calculated in the reference case is −1.30 Wm −2 . Uncertainties in the indirect forcing associated with aerosol and aerosol precursor emissions, aerosol mass concentrations from different chemical transport models, aerosol size distributions, the cloud droplet parameterization, the representation of the in-cloud updraft velocity, the relationship between effective radius and volume mean radius, cloud liquid water content, cloud fraction, and the change in the cloud drop single scattering albedo due to the presence of black carbon are calculated. The aerosol burden calculated by chemical transport models and the cloud fraction are found to be the most important sources of uncertainty. Variations in these parameters cause an underestimation or overestimation of the indirect forcing compared to the base case by more than 0.6 Wm −2 . Uncertainties associated with aerosol and aerosol precursor emissions, uncertainties in the representation of the aerosol size distribution (including the representation of the pre-industrial size distribution), and uncertainties in the representation of cloud droplet spectral dispersion effect cause uncertainties in the global mean forcing of 0.2∼0.6 Wm −2 . There are significant regional differences in the uncertainty associated with the first indirect forcing with the largest uncertainties in industrial regions (North America, Europe, East Asia) followed by those in the major biomass burning regions.

The IPCC has stressed the importance of producing unbiased estimates of the uncertainty in indirect aerosol forcing, in order to give policy makers as well as research managers an understanding of the most important aspects of climate change that require refinement. In this study, we use 3-D meteorological fields together with a radiative transfer model to examine the spatially-resolved uncertainty in estimates of the first indirect aerosol forcing. The global mean forcing calculated in the reference case is −1.30 Wm −2. Uncertainties in the indirect forcing associated with aerosol and aerosol precursor emissions, aerosol mass concentrations from different chemical transport models, aerosol size distributions , the cloud droplet parameterization, the representation of the in-cloud updraft velocity, the relationship between effective radius and volume mean radius, cloud liquid water content, cloud fraction, and the change in the cloud drop single scattering albedo due to the presence of black carbon are calculated. The aerosol burden calculated by chemical transport models and the cloud fraction are found to be the most important sources of uncertainty. Variations in these parameters cause an underestimation or overestimation of the indirect forcing compared to the base case by more than 0.6 Wm −2. Uncertainties associated with aerosol and aerosol precursor emissions, uncertainties in the representation of the aerosol size distribution (including the representation of the pre-industrial size distribution), and uncertainties in the representation of cloud droplet spectral dispersion effect cause uncertainties in the global mean forcing of 0.2∼0.6 Wm −2. There are significant regional differences in the uncertainty associated with the first indirect forcing with the largest uncertainties in industrial regions (North America, Europe, East Asia) followed by those in the major biomass burning regions .

No abstract

The structure of the neutron-deficient 9 C isotope was studied via elastic scattering of radioactive 8 B on protons. An excitation function for resonance elastic scattering was measured in the energy range from 0.5 to 3.2 MeV in the center-of-momentum system. A new excited state in 9 C was observed at an excitation energy of 3.6 MeV. An R-matrix analysis indicates spin-parity 5/2 − for the new state. The results of this experiment are compared with continuum shell-model calculations.

We combine 150-fs holographic gating with specifically adapted electronic holography techniques to produce transmission images of objects embedded in diffusing material. The technique captures, without the use of scanning procedures, complete two-dimensional images with 150-fs temporal resolution, thereby yielding submillimeter spatial resolution through diffusing objects several centimeters thick.

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We present systematic studies of the temperature dependence of linewidths and lifetimes of excitonic transitions in quantum wells grown by molecular beam epitaxy using both photoluminescence and optical absorption. The temperature ranged from GI< to room temperature. Samples under investigation were lattices matched Ga.ils/AlGaAs and InGaAs/InAlA s, and strained InGaAs/GaAs and ln-GaPls/AlGaAs quantum well systems.