Materials Literature
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A diffuse interface (phase field) model for an electrochemical system is developed. We describe the minimal set of components needed to model an electrochemical interface and present a variational derivation of the governing equations. With a simple set of assumptions: mass and volume constraints, Poisson's equation,…
A family of red light-emitting star-shaped porphyrins with four monodisperse conjugated oligofluorene arms was prepared by using two key reactions: Lindsey condensation and Suzuki-Miyaura cross coupling reactions. All porphyrins exhibit high quantum yields (about 0.22) and good solubility in common organic solvents, a…
As a first step towards understanding the morphology of PdO crystals we performed a systematic full-potential density-functional theory study of all possible $(1\ifmmode\times\else\texttimes\fi{}1)$ terminations of the low-index surfaces of tetragonal PdO. Applying the concept of first-principles atomistic thermodynam…
Nanocrystalline SnO2 quantum dots were synthesized at room temperature by hydrolysis reaction of SnCl2. The addition of tetrabutyl ammonium hydroxide and the use of hydrothermal treatment enabled one to obtain tin dioxide colloidal suspensions with mean particle radii ranging from 1.5 to 4.3 nm. The photoluminescent p…
Bismuth ferrite is a magnetoelectric material, which simultaneously has polarization and spin orders. We have used electron spin resonance (ESR) as a local probe of the magnetic order in the magnetic-field range of 0--25 T, in the frequency domain of 115--360 GHz, and at a temperature of 4.2 K. The data reveal signifi…
In order to develop a yellow phosphor that emits efficiently under the 450–470 nm excitation range, we have synthesized a Eu2+-activated Sr3SiO5 yellow phosphor and attempted to develop white light-emitting diodes (LEDs) by combining them with a InGaN blue LED chip (460 nm). Two distinct emission bands from the InGaN-…
Nanoscale structural and mechanical characterization of the shell of a red abalone has been carried out. Cobble-like polygonal nanograins are basic building blocks that are used to construct individual aragonite platelets into a mother-of-pearl configuration known as nacre. The nanograin-structured aragonite platelets…
We have used a nonlithographic deposition process to form single polymeric nanowire chemical sensors. Oriented polyaniline nanowires, with diameters on the order of 100 nm, were deposited on gold electrodes. The devices showed a rapid and reversible resistance change upon exposure to NH 3 gas at concentrations as low…
Single-phased ferroelectromagnet BiFeO3 ceramics with high resistivity were synthesized by a rapid liquid phase sintering technique. Saturated ferroelectric hysteresis loops were observed at room temperature in the ceramics sintered at 880 °C for 450 s. The spontaneous polarization, remnant polarization, and the coerc…
Umicore IR Glass is a company specialising in the production of chalcogenide glasses and moulded optics. The standard glass compositions are GASIR1 (Ge<sub>22</sub>As<sub>20</sub>Se<sub>58</sub>) and GASIR2 (Ge<sub>20</sub>Sb<sub>15</sub>Se<sub>65</sub>). These materials are transparent in the 3-5 μm and 8-12 μm…
Ultrathin oxygenated amorphous CdTe (a-CdTe:O) films are prepared by rf sputtering of CdTe in a background of argon or argon/nitrogen/oxygen mixtures. Atomic force microscopy (AFM) is used to characterize the films and shows that they have an island structure typical of most sputtered thin films. However, when suffici…
The coating deposition on large optical components (diameter 350 mm) has required the development of new metrology tools at 1064 nm. To give realistic values of the optical performances, the whole surface of the component needs to be scanned. Our scatterometer (commercial system) has been upgraded to support large and…
Experimental and theoretical studies of a novel family of germanium-carbon clusters (Ge(n)C(m)) that were initiated with our earlier identification of the GeC(3)Ge cluster have now been extended to the GeC(7) and GeC(9) chains. The new clusters, which were formed by laser ablation and trapped in solid Ar at approximat…
Abstract For Abstract see ChemInform Abstract in Full Text.
We explore Raman microprobe capabilities of visualizing single-wall carbon nanotubes (SWCNTs). Although this technique is limited to the micron scale, we demonstrate that images of individual SWCNTs, bundles, or their agglomerates can be generated by mapping Raman active elementary excitations. We measured the Raman r…
Ceramics are generally thought to be much more brittle than metals or polymers. At the nanoscale, however, ceramic materials can exhibit surprising flexibility. In his Perspective, Korgel discusses work reported in the same issue by Kong et al. on the synthesis of nanocoils of zinc oxide. Nanoribbons created by vapor…
We report the chemical changes and phase formation at the film-SiO2 interface during vacuum annealing of supersaturated Cu–10 at. % Mg alloy films sputter-deposited on SiO2. High-resolution transmission electron microscopy, energy dispersive x-ray spectroscopy and electron energy loss spectroscopy reveal that both Cu…
Using argon as the transporting gas, freestanding macroscopic ZnO strands have been synthesized by evaporating metal zinc pellets at 900 °C in a quartz tube. Scanning electron microscopy images show that the macroscopic ZnO strands are self-twined by ZnO nanowires with a diameter in the range of 20–30 nm. A ZnO strand…
The Landau-de Gennes free energy is used to calculate the interaction between long cylindrical colloids and the nematic-isotropic (NI) interface. This interaction has two contributions: one is specific of liquid crystals and results from the deformation of the director field close to the particles or to the interface,…
The observation of field induced electron emission from room temperature grown carbon nanofibers at low (5 V/μm) macroscopic electric fields is reported. The nanofibers were deposited using methane as a source gas in a conventional rf plasma enhanced chemical vapor deposition reactor using a Ni metal catalyst previous…