1,090 research outputs found
Change of Electronic Structure Induced by Magnetic Transitions in CeBi
The temperature dependence of the electronic structure of CeBi arising from
two types of antiferromagnetic transitions based on optical conductivity
() was observed. The spectrum continuously and
discontinuously changes at 25 and 11 K, respectively. Between these
temperatures, two peaks in the spectrum rapidly shift to the opposite energy
sides as the temperature changes. Through a comparison with the band
calculation as well as with the theoretical spectrum, this
peak shift was explained by the energy shift of the Bi band due to the
mixing effect between the Ce and Bi states. The single-layer
antiferromagnetic () transition from the paramagnetic state was concluded
to be of the second order. The marked changes in the spectrum
at 11 K, however, indicated the change in the electronic structure was due to a
first-order-like magnetic transition from a single-layer to a double-layer
() antiferromagnetic phase.Comment: 4 pages, to be published in J. Phys. Soc. Jpn. 73 Aug. (2004
Rhodium-catalyzed dehydrogenative borylation of cyclic alkenes
A rhodium-catalyzed dehydrogenative borylation of cyclic alkenes is described. This reaction provides direct access to cyclic 1-alkenylboronic acid pinacol esters, useful intermediates in organic synthesis. SuzukiāMiyaura cross-coupling applications are also presented.National Institute of General Medical Sciences (U.S.) (GM-63755
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Carbon brainprint - An estimate of the intellectual contribution of research institutions to reducing greenhouse gas emissions
This is the accepted manuscript of a paper published in Process Safety and Environmental Protection (Chatterton J, et al., Process Safety and Environmental Protection, 2015, 96, 74-81, doi:10.1016/j.psep.2015.04.008). The final version is available at http://dx.doi.org/10.1016/j.psep.2015.04.008Research and innovation have considerable, currently unquantified potential to reduce greenhouse gas emissions by, for example, increasing energy efficiency. Furthermore, the process of knowledge transfer in itself can have a significant impact on reducing emissions, by promoting awareness and behavioural change. The concept of the ācarbon brainprintā was proposed to convey the intellectual contribution of higher education institutions to the reduction of greenhouse gas emissions by other parties through research and teaching/training activities. This paper describes an investigation of the feasibility of quantifying the carbon brainprint, through six case studies. The potential brainprint of higher education institutes is shown to be significant: up to 500 kt CO2e/year for one project. The most difficult aspect is attributing the brainprint among multiple participants in joint projects.The Carbon Brainprint project was supported by the Higher Education Funding Council for England (HEFCE) under its Leading Sustainable Development in Higher Education programme, with support for case studies from Santander Universities. HEFCE, Research Councils UK and the Carbon Trust were members of the Steering Committee, which provided guidance, but did not direct the research. The Carbon Trust also advised on best practice in carbon footprinting.
We are grateful to the many university staff at Cranfield, Cambridge and Reading Universities who shared their work with us so enthusiastically.
We also thank the external partners and clients for the projects on which these case studies are based: Rolls-Royce plc, the ETI NOVA consortium, IGD, the Environment Agency, Esso, Repsol YPF, Carnego Systems Ltd. and Newera Controls Ltd
High-resolution mass models of dwarf galaxies from LITTLE THINGS
We present high-resolution rotation curves and mass models of 26 dwarf galaxies from LITTLE THINGS. LITTLE THINGS is a high-resolution Very Large Array HI survey for nearby dwarf galaxies in the local volume within 11 Mpc. The rotation curves of the sample galaxies derived in a homogeneous and consistent manner are combined with Spitzer archival 3.6 micron and ancillary optical U, B, and V images to construct mass models of the galaxies. We decompose the rotation curves in terms of the dynamical contributions by baryons and dark matter halos, and compare the latter with those of dwarf galaxies from THINGS as well as Lambda CDM SPH simulations in which the effect of baryonic feedback processes is included. Being generally consistent with THINGS and simulated dwarf galaxies, most of the LITTLE THINGS sample galaxies show a linear increase of the rotation curve in their inner regions, which gives shallower logarithmic inner slopes alpha of their dark matter density profiles. The mean value of the slopes of the 26 LITTLE THINGS dwarf galaxies is alpha =-0.32 +/- 0.24 which is in accordance with the previous results found for low surface brightness galaxies (alpha = -0.2 +/- 0.2) as well as the seven THINGS dwarf galaxies (alpha =-0.29 +/- 0.07). However, this significantly deviates from the cusp-like dark matter distribution predicted by dark-matter-only Lambda CDM simulations. Instead our results are more in line with the shallower slopes found in the Lambda CDM SPH simulations of dwarf galaxies in which the effect of baryonic feedback processes is included. In addition, we discuss the central dark matter distribution of DDO 210 whose stellar mass is relatively low in our sample to examine the scenario of inefficient supernova feedback in low mass dwarf galaxies predicted from recent Lambda SPH simulations of dwarf galaxies where central cusps still remain.Peer reviewe
Band Calculation for Ce-compounds on the basis of Dynamical Mean Field Theory
The band calculation scheme for electron compounds is developed on the
basis of the dynamical mean field theory (DMFT) and the LMTO method. The
auxiliary impurity problem is solved by a method named as NCAv', which
includes the correct exchange process of the virtual
excitation as the vertex correction to the non-crossing approximation (NCA) for
the fluctuation. This method leads to the correct magnitude
of the Kondo temperature, , and makes it possible to carry out
quantitative DMFT calculation including the crystalline field (CF) and the
spin-orbit (SO) splitting of the self-energy. The magnetic excitation spectra
are also calculated to estimate . It is applied to Ce metal and CeSb
at T=300 K as the first step. In Ce metal, the hybridization intensity (HI)
just below the Fermi energy is reduced in the DMFT band. The photo-emission
spectra (PES) have a conspicuous SO side peak, similar to that of experiments.
is estimated to be about 70 K in -Ce, while to be about
1700 K in -Ce. In CeSb, the double-peak-like structure of PES is
reproduced. In addition, which is not so low is obtained because HI
is enhanced just at the Fermi energy in the DMFT band.Comment: 30pages, 18 figure
Intracochlear schwannoma presenting as diffuse cochlear enhancement: diagnostic challenges of a rare cause of deafness
Intracochlear schwannoma is a rare, treatable, cause of unilateral hearing loss. Due to the small size, position, and variable clinical and imaging features, diagnosis presents a significant challenge and is often delayed. We present a case of a patient with an intracochlear schwannoma presenting as a diffuse enhancement of the cochlea, mimicking an infectious or inflammatory process. The absence of focal nodularity in this lesion on multiple high-resolution MRI examinations led to a delay of over 3 years from the patientās initial presentation to surgical diagnosis. Clinical history and examination, imaging features, pathologic findings, and surgical management options are described
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