Titania/alumina bilayer gate insulators for InGaAs metal-oxide-semiconductor devices

We describe the electrical properties of atomic layer deposited TiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> bilayer gate oxides which simultaneously achieve high gate capacitance density and low gate leakage current density. Crystallization of the initially amorphous TiO<sub>2</sub> film contributes to a significant accumulation capacitance increase (∼33%) observed after a forming gas anneal at 400 °C. The bilayer dielectrics reduce gate leakage current density by approximately one order of magnitude at flatband compared to Al<sub>2</sub>O<sub>3</sub> single layer of comparable capacitance equivalent thickness. The conduction band offset of TiO<sub>2</sub> relative to InGaAs is 0.6 eV, contributing to the ability of the stacked dielectric to suppress gate leakage conduction

Search for Q: single grains Xe isotope analysis of carbonaceous residue from Yilmia

We analyse Xe in single grains in HF-HCl residue from Yilmia using RELAX mass spectrometer

HST/STIS Imaging of the Host Galaxy of GRB980425/SN1998bw

We present HST/STIS observations of ESO 184-G82, the host galaxy of the gamma-ray burst GRB 980425 associated with the peculiar Type Ic supernova SN1998bw. ESO 184-G82 is found to be an actively star forming SBc sub-luminous galaxy. We detect an object consistent with being a point source within the astrometric uncertainty of 0.018 arcseconds of the position of the supernova. The object is located inside a star-forming region and is at least one magnitude brighter than expected for the supernova based on a simple radioactive decay model. This implies either a significant flattening of the light curve or a contribution from an underlying star cluster.Comment: 12 pages, 2 figures, AASTeX v5.02 accepted for publication in ApJ Letter

MOS CCDs for the wide field imager on the XEUS spacecraft

In recent years the XEUS mission concept has evolved and has been the subject of several industrial studies. The mission concept has now matured to the point that it could be proposed for a Phase A study and subsequent flight programme. The key feature of XEUS will be its X-ray optic with collecting area ~30-100x that of XMM. The mission is envisaged at an orbit around the L2 point in space, and is formed from two spacecraft; one for the mirrors, and the other for the focal plane detectors. With a focal length of 50m, the plate scale of the optic is 6.5x that of XMM, which using existing focal plane technology will reduce the effective field of view to a few arc minutes. Cryogenic instrumentation, with detector sizes of a few mm can only be used for narrow field studies of target objects, and a wide field instrument is under consideration using a DEPFET pixel array to image out to a diameter of 5 arcminutes, requiring an array of dimension 70mm. It is envisaged to extend this field of view possibly out to 15 arcminutes through the use of an outer detection ring comprised of MOS CCD

On the available evidence for the temperature dependence of soil organic carbon

International audienceTwo recent papers by Knorr et al. (2005) and Fang et al. (2005) provide variations of model fitting conducted in the former study. Knorr et al. (2005) suggested that more recalcitrant fractions of soil organic carbon (SOC) could be more sensitive to temperature. Fang et al. (2005) argue that this is an implication of the choice of model used. Further, Reichstein et al. (2005) point out that the evidence for a stronger temperature sensitivity of recalcitrant soil carbon mainly rests on an analysis of data provided by Kätterer et al. (1998) and argue for a different selection criterion to exclude short-term incubations. Here, we explain why the model used by Knorr et al. (2005) is the simplest multi-pool model that can fit the available data and is at the same time fully consistent with the concept of "pools", as opposed to some of the model formulations proposed by Fang et al. (2005). It is also pointed out that the criterion proposed by Reichstein et al. (2005) uses posterior information to determine inclusion of experimental data, a practice that should be avoided. We conclude that the original analysis of Knorr et al. (2005) as well as the one added by Fang et al. (2005) indicate that there is a serious possibility that recalcitrant SOC reacts more to temperature changes than labile SOC

Seasonal differences in the response of Arctic cyclones to climate change in CESM1

The dramatic warming of the Arctic over the last three decades has reduced both the thickness and extent of sea ice, opening opportunities for business in diverse sectors and increasing human exposure to meteorological hazards in the Arctic. It has been suggested that these changes in environmental conditions have led to an increase in extreme cyclones in the region, therefore increasing this hazard. In this study, we investigate the response of Arctic synoptic scale cyclones to climate change in a large initial value ensemble of future climate projections with the CESM1-CAM5 climate model (CESM-LE). We find that the response of Arctic cyclones in these simulations varies with season, with significant reductions in cyclone dynamic intensity across the Arctic basin in winter, but with contrasting increases in summer intensity within the region known as the Arctic Ocean cyclone maximum. There is also a significant reduction in winter cyclogenesis events within the Greenland–Iceland–Norwegian sea region. We conclude that these differences in the response of cyclone intensity and cyclogenesis, with season, appear to be closely linked to changes in surface temperature gradients in the high latitudes, with Arctic poleward temperature gradients increasing in summer, but decreasing in winter