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Chemists have synthesized a highly selective and highly efficient zirconium catalyst that makes new carbon-nitrogen bonds by adding a nitrogen-hydrogen bond to a carbon-carbon double bond. Nitrogen-containing chemicals are important as agrichemicals, pharmaceu
A material that is magnetic, superconducting and behaves nearly like a semiconducting sounds fairly unusual, and it is. Just such a material, made from potassium, iron and selenium, was recently discovered. It has similar superconducting properties to iron-arsenide-based superconductors. However, it is also nearly semiconducting and, most curious, has a very high (antiferro-)magnetic ordering temperature with large (rather than small) magnetic moments.
A novel electrode architecture has led to a new way to make transparent electrical contacts. Typical ways of attaching a conductor to a non-metallic material allow you to see the electrode. However, for many applications, like light emitting diode (LED) displays, smart windows and solar cells, transparency to visible light is a requirement that conflicts with electrical conductance. Thinner films are more transparent, but less conductive. The new architecture consists of specially patterned nanoscale-thick metallic ribbons, standing on edge, supported by a polymer matrix.
Researchers have wrestled with the question of whether or not the newest superconducting materials fit within the traditional classifications. Superconductors can be divided into Type 1 and Type 2, depending on how they behave in a magnetic field. However, magnesium diboride was discovered to have characteristics of both categories and has been dubbed “Type 1.5”.
An international team of researchers has discovered a new type of defect in an unconventional material known as a quasicrystal. Mysterious nanodomains observed on the surfaces of quasicrystals led to the discovery. Quasicrystals were already known to have a unique defect type, known as a phason flip, which can form at the surface. The new defect type is related, but unlike the phason flip is not restricted to the surface; it bridges the surface and the bulk.
Graphene is supposed to have the potential to replace silicon in electronic devices, making them thinner and faster, but making such devices depends on making electrical contacts. Researchers have deposited two metals onto graphene — a one atom thick layer of carbon — to see what kinds of elements might work best. Metals like lead were predicted to attach weakly, while rare earth metals were predicted to stick strongly giving better results. Scanning tunneling microscopy experiments confirmed the predictions.
Ions in water with the same charge, e.g. Fe3+ and La3+, behave dramatically differently at the air/water interface when interacting with a charged surface. This difference violates classic electrostatic theory. The distributions of specific ion types were determined with unprecedented precision using newly developed surface sensitive synchrotron x-ray scattering and spectroscopic techniques. The research team was able to use these results to verify their recently-developed theoretical model that takes into account both classical and effective quantum behavior.
Researchers have discovered how the geometry of gold nanoparticles affects their images. Gold nanoparticles can be imaged optically and their movements can be seen using a technique known as differential interference contrast (DIC) microscopy. How gold nanoparticles appear in these images depends upon their environment. This can be used to learn about time-dependent nanoscale processes.