Electronic and Thermoelectric Properties of RuIn_{3-x}A_{x} (A = Sn, Zn)

Recently, we reported [M. Wagner et al., J. Mater. Res. 26, 1886 (2011)] transport measurements on the semiconducting intermetallic system RuIn3 and its substitution derivatives RuIn_{3-x}A_{x} (A = Sn, Zn). Higher values of the thermoelectric figure of merit (zT = 0.45) compared to the parent compound were achieved by chemical substitution. Here, using density functional theory based calculations, we report on the microscopic picture behind the measured phenomenon. We show in detail that the electronic structure of the substitution variants of the intermetallic system RuIn_{3-x}A_{x} (A = Sn, Zn) changes in a rigid-band like fashion. This behavior makes possible the fine tuning of the substitution concentration to take advantage of the sharp peak-like features in the density of states of the semiconducting parent compound. Trends in the transport properties calculated using the semi-classical Boltzmann transport equations within the constant scattering time approximation are in good agreement with the former experimental results for RuIn_{3-x}Sn_{x}. Based on the calculated thermopower for the p-doped systems, we reinvestigated the Zn-substituted derivative and obtained ZnO-free RuIn_{3-x}Zn_{x}. The new experimental results are consistent with the calculated trend in thermopower and yield large zT value of 0.8.Comment: PRB Accepted, 11 pages, 10 figure

Proton energy loss in multilayer graphene and carbon nanotubes

Results of a study of electronic energy loss of low keV protons interacting with multilayer graphene targets are presented. Proton energy loss shows an unexpectedly high value as compared with measurements in amorphous carbon and carbon nanotubes. Furthermore, we observe a classical linear behavior of the energy loss with the ion velocity but with an apparent velocity threshold around 0.1 a.u., which is not observed in other carbon allotropes. This suggests low dimensionality effects which can be due to the extraordinary graphene properties.This work was mainly supported by the grants Fondecyt [grant number 1100759], CONICYT-MEC [grant number 80150073] and DGIIP-UTFSM [grant number 216.11.3]. MM and BF acknowledge the Basal Program for Centers of Excellence, Grant FB0807 CEDENNA, CONICYT. RGM and IA acknowledge financial support provided by the Spanish Ministerio de Economía y Competitividad and the European Regional Development Fund (Project No. FIS2014-58849-P), as well as by the Fundación Séneca (Project No. 19907/GERM/15)

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

Chemical Bonding and Physical Properties of Yb5Bi3Yb_{5}Bi_{3}

The binary compound Yb 5 Bi 3 was synthesized by reaction of the elements in a sealed Ta container. Its crystal structure was determined from single-crystal X-ray diffraction data: β -Yb 5 Sb 3 -type, space group Pnma, Pearson code oP32, a = 12.6375(6), b = 9.7243(4), c = 8.4117(5)Å, V = 1033.72(9)Å 3 , Z = 4, R gt (F) = 0.028, wR ref (F 2 ) = 0.069, T = 290 K. Band structure calculations and analysis of the chemical bonding suggest mainly ionic interactions in the crystal structure and a possible presence of ytterbium in two valence states Yb 2+ and Yb 3+ . The magnetization measurements showed that at low temperatures Yb 5 Bi 3 contains ytterbium exclusively in the 4 f 14 configuration without fluctuations to the Yb 4 f 13 configuration up to 400 K. From the Yb-L III X-ray absorption spectroscopy data the effective valence of ytterbium was found to be 2.11 (89 % of Yb in 4 f 14 configuration)

Exchange Interactions Through π π Stacking in the Lamellar Compound [{Cu(bipy)(en)}{Cu(bipy)(H2O)}{VO3}4]n

Structural, magnetic, and powder and single crystal electronic paramagnetic resonance (EPR) studies are reported for [{Cu(bipy)(en)}{Cu(bipy)(H2O)}{VO3}4]n, a new copper-vanadium hybrid organic-inorganic compound containing CuII and VV centers. This first single crystal EPR study of an oxovanadium based organo-inorganic hybrid material functionalized with CuII complexes allows evaluating extremely weak exchange couplings and observing a dimensional quantum phase transition.Fil: Venegas Yazighi, Diego. Centro para el Desarrollo de Nanociencias y Nanotecnología; Chile. Universidad de Santiago de Chile; ChileFil: Brown, Kareen. Centro para el Desarrollo de Nanociencias y Nanotecnología; Chile. Universidad de Chile; ChileFil: Vega, Andrés. Centro para el Desarrollo de Nanociencias y Nanotecnología; Chile. Universidad Andres Bello; ChileFil: Calvo, Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentina. Universidad Nacional del Litoral; ArgentinaFil: Aliaga, Carolina. Centro para el Desarrollo de Nanociencias y Nanotecnología; Chile. Universidad de Santiago de Chile; ChileFil: Santana, Ricardo. Universidade Federal de Goias; BrasilFil: Cardoso Gil, Raul. Max-Planck-Institut für Chemische Physik fester Stoffe; AlemaniaFil: Kniep, Rüdiger . Max-Planck-Institut für Chemische Physik fester Stoffe; AlemaniaFil: Schnelle, Walter. Max-Planck-Institut für Chemische Physik fester Stoffe; AlemaniaFil: Spodine, Evgenia. Centro para el Desarrollo de Nanociencias y Nanotecnología; Chil

Structural complexity of the intermetallic compound o-Al13Co4

The crystal structure of the complex intermetallic phase o-Al13Co4 was first investigated in 1994, but some open questions still remained. The new refinement of the crystal structure using high-resolution X-ray diffraction data resulted in a much more complex model including a large number of split positions (space group Pnm21, a = 8.1590(6) Å, b = 12.349(1) Å, c = 14.453(1) Å). The model is interpreted in terms of local violation of the translational symmetry, which is confirmed by HRTEM and HRSTEM investigations. Chemical bonding between two partial structures in o-Al13Co4 - three-dimensional framework and linear Co–Al–Co groups in cages of the latter – along with the stacking faults (local twinning) are discussed as possible reasons for such an extended disorder. Previous article in issu

Key properties of inorganic thermoelectric materials – tables (version 1)

This paper presents tables of key thermoelectric properties, which define thermoelectric conversion efficiency, for a wide range of inorganic materials. The 12 families of materials included in these tables are primarily selected on the basis of well established, internationally-recognised performance and promise for current and future applications, but also for alternatve bonding and transport behaviour: Tellurides, Skutterudites, Half Heuslers, Zintls, Mg-Sb Antimonides, Clathrates, FeGa3–type materials, Actinides and Lanthanides, Oxides, Sulfides, Selenides, Silicides, Borides and Carbides. As thermoelectric properties vary with temperature, data are presented at room temperature to enable ready comparison, and also at a higher temperature appropriate to peak performance. An individual table of data and commentary are provided for each family of materials plus source references for all the data