Phonon confinement and interface lattice dynamics of ultrathin high-k rare earth sesquioxide films: the case of Eu2O3 on YSZ(001)

We demonstrate that sub-nanometer-thick layers exhibiting exotic crystal phases that might form at the interface between two materials constitute a source of novel vibrational dynamics of thin films and multilayers.

Quantification and Trend Analysis of Multidecadal Global Dissolved Oxygen Changes

Previous studies have found there to be measurable deoxygenation in regions of the world’s oceans, with changes linked to biogeochemical cycles, changes in ocean productivity, and climate fluctuations. Here, we investigated multidecadal large-scale dissolved oxygen trends in the principal basins of the Atlantic, Pacific, and Indian Oceans using data from WOCE, CLIVAR, and GO-SHIP cruises, representing some of the highest quality available water column data. We differenced spatially coincident older and more recent data, averaged differences in geographic subregions, and integrated results on 500-dbar thick layers from 500 dbar to 3500 dbar, with bottom levels extending to 6000 dbar. Overall, we found a deoxygenation below 500 dbar across all major basins at a global average rate of -0.06 µmol kg−1 year−1, with important variations between regions and layers. Our research demonstrates a deoxygenation trend coincident with the global ocean warming and increased stratification trends documented in other studies.

Nanoimprinted and Anodized Templates for Large-Scale and Low-Cost Nanopatterning

Nanopatterning to fabricate advanced nanostructured materials is a widely employed technology in a broad spectrum of applications going from spintronics and nanoelectronics to nanophotonics. This work reports on an easy route for nanopatterning making use of ordered porous templates with geometries ranging from straight lines to square, triangular or rhombohedral lattices, to be employed for the designed growth of sputtered materials with engineered properties. The procedure is based on large-scale nanoimprinting using patterned low-cost commercial disks, as 1-D grating stamps, followed by a single electrochemical process that allows one to obtain 1-D ordered porous anodic templates. Multiple imprinting steps at different angles enable more complex 2-D patterned templates. Subsequently, sputtering facilitates the growth of ferromagnetic antidot thin films (e.g., from 20 to 100 nm Co thick layers) with designed symmetries. This technique constitutes a non-expensive method for massive mold production and pattern generation avoiding standard lithographical techniques. In addition, it overcomes current challenges of the two-stage electrochemical porous anodic alumina templates: (i) allowing the patterning of large areas with high ordering and/or complex antidot geometries, and (ii) being less-time consuming.

A 3D LTCC-Based Ceramic Microfluidic System with RF Dielectric Heating of Liquids

The design, fabrication and functional evaluation of the radio-frequency dielectric heating of liquids in an LTCC-based ceramic microfluidic system are described and discussed. The device, which relies on the dielectric heating of liquids, was fabricated using a low temperature co-fired ceramic (LTCC) technology. A multilayered ceramic structure with integrated electrodes, buried channels and cavities in micro and millimetre scales was fabricated. The structure with the dimensions of 35 mm × 22 mm × 2.4 mm includes a buried cavity with a diameter of 17.3 mm and a volume of 0.3 mL. The top and bottom faces of the cavity consist of silver/palladium electrodes protected with 100 μm thick layers of LTCC. The power, used to heat a polar liquid (water) in the cavity with the volume of 0.3 mL, ranges from 5 to 40 W. This novel application of RF dielectric heating could enable the miniaturization of microfluidic systems in many applications. The working principle of such a device and its efficiency are demonstrated using water as the heated medium.

Study of Ga2O3 deposition by MOCVD

Growth of Ga2O3 by metalorganic chemical vapour deposition in horizontal flow reactor from trimethylgallium (TMG) and oxygen is studied in a wide temperature range. The growth rate is directly proportional to TMG flow, weakly affected by O2 flow and non-monotonically depends on temperature. Growth rate over 3 μm/h is demonstrated, indicating that TMG can be used for growth of β-Ga2O3 thick layers for device applications.

Polymerization kinetics of experimental resin composites functionalized with conventional (45S5) and a customized low-sodium fluoride-containing bioactive glass

This study aimed to investigate polymerization kinetics and curing light transmittance of two series of experimental dental resin composites filled with 0–40 wt% of either 45S5 bioactive glass (BG) or a customized low-Na F-containing BG. Polymerization kinetics in 0.1-mm and 2-mm thick layers were investigated through real-time degree of conversion measurements using a Fourier transform infrared (FTIR) spectrometer. FTIR spectra were continuously collected at a rate of 2 s−1 during light-curing (1340 mW/cm2). Light transmittance through 2-mm thick composite specimens was measured using a UV–Vis spectrometer at a rate of 20 s−1. Unlike BG 45S5, which led to a dose-dependent reduction in the rate and extent of polymerization, the customized low-Na F-containing BG showed a negligible influence on polymerization. The reduction in light transmittance of experimental composites due to the addition of the low-Na F-containing BG did not translate into impaired polymerization kinetics. Additionally, the comparison of polymerization kinetics between 0.1-mm and 2-mm thick layers revealed that polymerization inhibition identified for BG 45S5 was not mediated by an impaired light transmittance, indicating a direct effect of BG 45S5 on polymerization reaction. A customized low-Na F-containing BG showed favourable behaviour for being used as a functional filler in light-curing dental resin composites.

Indium-Based Micro-Bump Array Fabrication Technology with Added Pre-Reflow Wet Etching and Annealing

Indium-based micro-bump arrays, among other things, are used for the bonding of infrared photodetectors and focal plane arrays. In this paper, several aspects of the fabrication technology of micrometer-sized indium bumps with a smooth surface morphology were investigated. The thermal evaporation of indium has been optimized to achieve ~8 μm-thick layers with a small surface roughness of Ra = 11 nm, indicating a high packing density of atoms. This ensures bump uniformity across the sample, as well as prevents oxidation inside the In columns prior to the reflow. A series of experiments to optimize indium bump fabrication technology, including a shear test of single columns, is described. A reliable, repeatable, simple, and quick approach was developed with the pre-etching of indium columns in a 10% HCl solution preceded by annealing at 120 °C in N2.

Evaluation of Efficiency of Polymerization, Surface Roughness, Porosity and Adaptation of Flowable and Sculptable Bulk Fill Composite Resins

A new category of commercial bulk fill composite resins (CRs) enables the placement of 4-mm-thick layers as an alternative to the traditional time-consuming incremental technique. The purpose of the present study was to compare the efficiency of the polymerization, adaptation and porosity of two high-viscosity ‘sculptable’ bulk fill CRs (Filtek™ Bulk Fill (3M™ ESPE, St. Paul, MN, USA) and Tetric EvoCeram® Bulk Fill (Ivoclar Vivadent AG, Schwan, Liechtenstein)) and two low-viscosity ‘flowable’ bulk fill CRs (SureFil® SDR™ flow (Dentsply Sirona, Charlotte, NC, USA) and Tetric EvoFlow® Bulk Fill (Ivoclar Vivadent AG, Schaan, Liechtenstein)). Cylindrical samples of the bulk fill CRs (4 mm height × 10 mm diameter) were analyzed by Fourier-transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). Additionally, occlusal cavities were prepared in twelve extracted human molars and restored with the bulk fill CRs (n = 3 for each CR). The adaptation and porosity of the bulk fill CRs were evaluated by X-ray microcomputed tomography (µCT) with a 3D morphometric analysis, and the adaptation was also analyzed by scanning electron microscopy (SEM) on longitudinal vestibulo-oral sections of the restored teeth. The AFM analysis demonstrated that the surface roughness of the SureFil® SDR™ flow was higher than that of the Tetric EvoFlow® Bulk Fill and that the surface roughness of Filtek™ Bulk Fill was higher than that of Tetric EvoCeram® Bulk Fill. µCT and SEM confirmed that the flowable bulk fill CRs had excellent adaptation to the cavity walls. The 3D morphometric analysis showed the highest and lowest degrees of porosity in Filtek™ Bulk Fill and Tetric EvoFlow® Bulk Fill, respectively. In general, the flowable bulk fill CRs exhibited better adaptation, a higher efficiency of polymerization and lower porosity than the sculptable materials.

The World of Browsers

This chapter discusses the metabolism of giraffes. Giraffes obtain their energy and all the other nutrients needed to support their metabolism by browsing on leaves, fruits, and flowers of trees and shrubs. Wherever they live in Africa giraffes select browse from very few species but principally they browse plants of the Acacia clade. Typically their diet will contain ~15% protein, ~5% fat, ~30% fiber, and minerals, especially calcium and phosphorus, and will provide ~8500 kJ of energy per kilogram of dry matter eaten. Acquisition of browse is facilitated by the elongated shape of their heads, the anatomy of their atlanto-occipital joint, a long neck supported by a unique suspensory ligament, a long and flexible tongue, and high visual and olfactory acuity. The preferred height at which giraffes browse (~3 m) is higher than the height achievable by other browsers, is an advantage conferred by their shape, and is usual explanation for the evolution of their shape. Browse preferred by giraffes is protected from over-browsing by thorns, ants, and unpalatable plant secondary metabolites, especially tannins. Giraffes tolerate tannins partly by secretion of saliva rich in proline that binds tannins. Tannins are metabolized by a combination of a gene-based ability and a liver larger than it is in grazer-ruminants. Thorns are avoided but thick layers of keratin in the mouth and tongue provide protection. Browse containing ants also is avoided, but giraffes have well-developed anatomical protection for their faces especially their eyes and nostrils.

Morphological and Compositional Studies on Al/Ti/TiN/Si, Al/TiN/Si, Al/W/Si, Al/WN/Si Systems to Test the Diffusion Barrier Properties of Nanoscale-Thick Layers between Al and Si

In this work, an investigation of the properties of nanoscale-thick Ti/TiN, TiN, W, WN layers as diffusion barriers between Si and Al is carried out in view of Si-based electronic applications. Heat treatments were performed on the samples to activate interdiffusion between Si and Al. Changing annealing time and temperature, each sample was morphologically characterized by scanning electron microscopy and atomic force microscopy and compositionally characterized by Rutherford backscattering analysis. The aim is to evaluate the efficiency of the layers as diffusion barriers between Si and Al and, at the same time, to evaluate the surface morphological changes upon annealing processes.