derived from BaCO 3 . Small particle size has been shown to suppress a martensitic phase transition, and in this context microwave plasma synthesis appears rapid enough to prevent particle sintering and subsequent transition to the monoclinic phase. Prolonged exposure (1 h) to an O 2 or Ar plasma of either the orthorhombic or monoclinic phases did not result in a phase change as judged by powder XRD.In conclusion, we have used a simple microwave plasma reactor for reproducible bulk synthesis of several ternary niobate and titanate phases. MIP synthesis does not require direct interaction between a solid and microwave radiation and is, therefore, amenable to any solid-state reaction. Importantly, for some reactions the plasma can also be used to heat solids into a temperature regime where additional dielectric heating can occur, resulting in a local temperature much greater than the equilibrium MIP temperature. ExperimentalPrecursor oxides (Nb 2 O 5 , TiO 2 , and BaO 99.99 %) and carbonates (Li 2 CO 3 99.99 %, Na 2 CO 3 99.995 %, K 2 CO 3 99.995 %, CaCO 3 99.995+ %, BaCO 3 99.999 %, and PbCO 3 99.99+ %) were purchased from Aldrich and used as received. Plasma gases (Ar and O 2 ) were purchased from BOC. In a typical synthesis, a total mass of 2 g of precursors was ground in a drybox and pressed at 10 tonnes into a 13 mm pellet, and the pellet was transferred to the microwave apparatus via a desiccator. The pellet was placed in an alumina boat and exposed to a plasma at 13 mbar (1mbar = 10 2 Pa), 900 W, and a gas flow rate of 200 cm 3 min -1 for argon and 142 cm 3 min -1 for dioxygen. After microwave plasma irradiation, products were transferred directly into a drybox for storage. Products were characterized by powder X-ray diffraction (Philips 1800 diffractometer PH 03, with Cu Ka radiation (k = 1.54 Å) in reflection mode), scanning electron microscopy (FEI Sirion 200), and analytical transmission electron microscopy (FEI CM200 FEGTEM) that included electron energy loss spectroscopy (EELS). the synthesis of tubular nanomaterials has aroused worldwide interest -both in fundamental studies, and for their potential application in, for example, chemical sensors, and as catalysts and storage and/or release systems. [2][3][4][5] Zinc oxide (ZnO), a II-VI compound semiconductor, has many remarkable properties. The wide direct bandgap of ZnO (3.37 eV) and large exciton binding energy (∼ 60 meV at room temperature)

We have performed ab initio calculations to investigate the adsorption of Li onto the clean and oxygenated diamond C͑100͒ surface. Despite a large amount of interest in alkali-metal absorption on clean and oxidized semiconductor surfaces for both fundamental and technological applications, lithium adsorption on the diamond surface has not been reported. We find that Li adopts structures on the clean C͑100͒ surface similar to those reported for Na, K, and Rb on diamond, though Li exhibits significantly higher binding energies in the range 2.7-3.1 eV per Li adsorbate. For the oxygenated C͑100͒-͑1 ϫ 1͒ : O surface, the lowest energy involving a full Li monolayer structure shows an exceptionally large work-function shift of −4.52 eV relative to the clean surface, an effect similar to that seen for Csu O on diamond, but with a higher binding energy of 4.7 eV per Li atom. We propose that such a system, if verified by experiment, is suitable for the surface coating of diamond-based vacuum electronic devices, as it should exhibit higher thermal stability than the commonly used Csu O surface while retaining the advantage of a large lowering of the work function.

In this paper, a perspective on the application of Spatially- and Angle-Resolved PhotoEmission Spectroscopy (ARPES) for the study of two-dimensional (2D) materials is presented. ARPES allows the direct measurement of the electronic band structure of materials generating extremely useful insights into their electronic properties. The possibility to apply this technique to 2D materials is of paramount importance because these ultrathin layers are considered fundamental for future electronic, photonic and spintronic devices. In this review an overview of the technical aspects of spatially localized ARPES is given along with a description of the most advanced setups for laboratory and synchrotron-based equipment. This technique is sensitive to the lateral dimensions of the sample. Therefore, a discussion on the preparation methods of 2D material is presented. Some of the most interesting results obtained by ARPES are reported in three sections including: graphene, transition metal dichalcogenides (TMDCs) and 2D heterostructures. Graphene has played a key role in ARPES studies because it inspired the use of this technique with other 2D materials. TMDCs are presented for their peculiar transport, optical and spin properties. Finally, the section featuring heterostructures highlights a future direction for research into 2D material structures.

Experimental and modeling studies of the gas-phase chemistry occurring in dilute, hot filament (HF) activated B2H6/H2 and B2H6/CH4/H2 gas mixtures are reported. Spatially resolved relative number densities of B (and H) atoms have been measured by resonance enhanced multiphoton ionization methods, as a function of process conditions (e.g. the HF material and its temperature, the B2H6/H2 mixing ratio, and the presence (or not) of added CH4). Three-dimensional modeling of the H/B chemistry prevailing in such HF activated gas mixtures using a simplified representation of the gas phase chemistry succeeds in reproducing all of the experimentally observed trends, and in illustrating the key role of the "H-shifting" reactions BHx + H <= => BHx-1 + H2 (x = 1-3) in enabling rapid interconversion between the various BHx (x = 0-3) species. CH4 addition, at partial pressures appropriate for growth of boron-doped diamond by chemical vapor deposition methods, leads to approximately 30% reduction in the measured B atom signal near the HF. The modeling suggests that this is mainly due to concomitant H atom depletion near the HF, but it also allows us a first assessment of the possible contributions from B/C coupling reactions upon CH4 addition to HF activated B2H6/H2 gas mixtures.

Hypoproteinaemia may lead to spuriously high electrolyte values using indirect ion-selective electrodes (ISE) compared to direct ISEs. This study evaluates the impact on electrolyte status assessment of direct compared to indirect ISE sodium and potassium measurements in samples from critically ill patients who have a high prevalence of hypoproteinaemia. Serum sodium and potassium measurements were compared using indirect and direct ISE in 190 samples received from critical care units over a three-week period. Serum sodium and potassium measurements were higher (P < 0.0001) using indirect ISE (140.0 +/- 5.0 and 4.5 +/- 0.6, respectively) compared to direct ISE (136.5 +/- 5.2 and 4.5 +/- 0.6, respectively). The calculated difference between indirect and direct ISE values for sodium increased as total protein concentration decreased (Y = 7.2-0.07X, 95% CI slope -0.1 to -0.05, P<0.0001, r2 = 0.14). Hypoproteinaemia was present in 85% of samples. Indirect ISE, compared to direct ISE, misclassified 28% of samples as pseudonormonatraemia (19%), pseudohypernatraemia (8%), pseudonormokalaemia (0.8%) and pseudohyperkalaemia (0.4%). Hypoproteinaemia is common in critically ill patients and this may lead to spuriously high indirect ISE electrolyte measurements, resulting in significant misclassification of electrolyte (particularly sodium) status. In such patients, direct ISE (as employed in point-of-care testing) offers more accurate and consistent electrolyte results than does indirect ISE (commonly used in major laboratory analysers).