Materials Literature
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The coupled plasmon absorption of Au nanorod dimers is investigated as a function of the orientation between the long-axes of the nanorod by linking them with rigid and flexible molecules. As the angle between the Au nanorods increases, the coupled plasmon band shifts to longer wavelength confirming the role of effect…
Treatment of amorphous diphenylalanine thin film at high temperatures as 150 °C with aniline vapor under anhydrous condition results in the formation of vertically well-aligned nanowires. By combining the high-temperature aniline vapor aging method with a simple soft-lithographic technique, we could fabricate a micro-…
Abstract Multi‐walled carbon nanotubes (CNTs) and nitrogen‐doped carbon (CN x ) nanotubes have been synthesized by the aerosol‐assisted chemical vapour deposition (CVD) method. The samples were prepared from toluene and acetonitrile taken in different proportion. The structure of CNTs and CN x nanotubes was compared u…
A recipe is given for creating material with a desired refraction coefficient by embedding many small particles in a given material. To implement practically this recipe, some technological problems are to be solved. These problems are formulated.
The finite screening length by real metallic electrodes, albeit very small (<1A), results in finite depolarizing field that tends to split the film into domains. In very thin ferroelectric films the domain structure reduces to sinusoidal distribution of polarization considered first in the 1980s. We discuss the phase…
Room-temperature Raman scattering was measured in ZnWO4 up to 45 GPa. We report the pressure dependence of all the Raman-active phonons of the low-pressure wolframite phase. As pressure increases new Raman peaks appear at 30.6 GPa due to the onset of a reversible structural phase transition to a distorted monoclinic b…
Three first order magnetic phase transitions (FOMT) have been detected at TCPr, TNinter and TCinter over the temperature range from 5 K to 340 K at fields up to 9 T in PrMn1.4Fe0.6Ge2, and the magnetocaloric effect (MCE) around these transitions evaluated. The MCE of two FOMT from planar antiferromagnetism (AFl) to c-…
We investigate the binding nature of the endohedral sodium atoms with the ensity functional theory methods, presuming that the clathrate I consists of a sheaf of one-dimensional connections of Na@Si$_{24}$ cages interleaved in three perpendicular directions. Each sodium atom loses 30% of the 3s$^1$ charge to the frame…
Polypyrrole (PPy) is an inherently conducting polymer that has shown great promise for biomedical applications within the nervous system. However, to effectively use PPy as a biomaterial implant, it is important to understand and reproducibly control the electrical properties, physical topography and surface chemistry…
We demonstrate the local oxidation nanopatterning of graphene films by an atomic force microscope. The technique provides a method to form insulating trenches in graphene flakes and to fabricate nanodevices with sub-nanometer precision. We demonstrate fabrication of a 25-nm-wide nanoribbon and submicron size nanoring…
Barium titanate (BaTiO 3 ) ceramics with various grain sizes were prepared by a conventional sintering method and a two-step sintering method. The permittivity of the ceramics increased with decreasing the grain size down to 1.1 µm on average. The BaTiO 3 ceramics with an average grain size of 1.1 µm had a high permit…
Copper oxide nanoparticles with a particle size ranging from 80 to 160 nm were prepared by a wet chemical procedure. Copper carbonate hydroxide and sodium hydroxide were used as raw materials. Copper hydroxide was generated as a precursor which was thermally decomposed to CuO nanoparticles. The nanoparticles were char…
A series of layered (Sr 1-x K x )Fe 2 As 2 compounds with nominal x = 0-0.40 are synthesized by solid state reaction method. Similar to other parent compounds of iron-based pnictide superconductors, pure SrFe 2 As 2 shows a strong resistivity anomaly near 210 K, which was ascribed to the spin-density-wave instability.…
International audience
Soils of the cerrado biome, mostly oxisols and deep sandy entisols, are acid, dystrophic and poor in available nutrients. These soils are not very different from soils that occur in the Amazon region. However, the open savanna physiognomies of cerrado with lower biomass of their different components are deficient in n…
Abstract For high temperature thermoelectric applications, Yb 14 MnSb 11 has a maximum thermoelectric figure of merit ( zT ) of ∼1.0 at 1273 K. Such a high zT is found despite a carrier concentration that is higher than typical thermoelectric materials. Here, we reduce the carrier concentration with the discovery of a…
Abstract This paper addresses both old, but “renovated” methods and new methods for diffraction line-profile analysis. Classical and even extremely simple single-line methods for separating “size” and “strain” broadening effects have merit for characterization of the material imperfectness, but it is generally very di…
Abstract A novel kind of rattle‐type hollow magnetic mesoporous sphere (HMMS) with Fe 3 O 4 particles encapsulated in the cores of mesoporous silica microspheres has been successfully fabricated by sol–gel reactions on hematite particles followed by cavity generation with hydrothermal treatment and H 2 reduction. Such…
Monodisperse Au nanoparticles (NPs) have been synthesized at room temperature via a burst nucleation of Au upon injection of the reducing agent t -butylamine-borane complex into a 1, 2, 3, 4-tetrahydronaphthalene solution of HAuCl 4 ·3H 2 O in the presence of oleylamine. The as-synthesized Au NPs show size-dependent s…
Here the authors report that by a high pressure synthesis method, superconductivity with an onset transition temperature at 52 K was discovered in a fluorine-doped quaternary iron-arsenide compound Pr[O1-xFx]FeAs, with the zero resistivity and Meissner transition appeared at 44 K and 50 K respectively. As the first no…