The Poisson’s ratio of a material is defined as nij = –ej/ ei, where ej is the lateral strain in the j direction that is caused when a strain ei is applied in the longitudinal i direction. Negative Poisson’s ratios have previously been observed in foam- and polymer-based structures, in the non-cubic phases of arsenic […]
Physicists have studied the interaction of water with surfaces for centuries. Felix Savart, for instance, first studied shocks in shallow water in 1833. It is now well known that the maximum diameter that a droplet can achieve is determined by the ratio of two numbers – the Reynolds and Weber numbers – that are determined […]
One of RHIC’s main goals is to produce a quark-gluon plasma – the state of matter that is thought to have existed just millionths of a second after the big bang. Quarks are normally confined in neutrons, protons and other composite particles by the strong force, which is carried by gluons. In a quark-gluon plasma, […]
S Heinze and co-workers from the University of Hamburg and X Nie and colleagues from the Forschungszentrum Jülich have used “spin-polarized scanning tunelling microscopy” to image an antiferromagnetic layer of manganese atoms on a tungsten substrate. In antiferromagnetic materials, the direction of the magnetic moment alternates from one lattice site to the next, but there […]
The researchers used eight ceramic tips that were connected via a cantilever array to an atomic-force microscope. The tips were coated with a molecular ink such as 1-octadecanethiol that diffused from the tip onto the gold substrate. The ink reacts with the gold to produce a stable monolayer structure on the substrate. A pattern can […]
Gaidos and Nimmo say that the tidal forces from Jupiter can cause regions of ice near a fault or defect to move relative to one another. This relative motion causes frictional heating that increases the local temperature of the ice and makes it less viscous. This “warm ice”, which is estimated to have a temperature […]
The new Buyer’s Guide contains information on a wide range of physics equipment: cryogenics, lab electronics, lasers, magnets, microscopy, power supplies, test & measurement and vacuum are just some of the categories included in the Buyer’s Guide. More than 2000 companies are listed in the guide, and a sophisticated search facility makes it easy to […]
“Science is more controversial than art can ever be.” Strange words for an artist, perhaps, but Cornelia Parker has been inspired by science for many years. Indeed, Parker’s “Cold, dark matter” – the suspended remains of a garden shed that the army blew up on her behalf – is currently on show at the recently […]
Read article: Boomerang backs flat universe
The geometry of the universe is Euclidean and space is flat. This has now been confirmed from detailed measurements of the cosmic microwave background – the radiation left over from the big bang – by an international team of astronomers from Italy, the UK, the US, Canada and France. The Boomerang collaboration, led jointly by […]
Read article: Carbon nanotubes roll on
The remarkable properties of carbon nanotubes may allow them to play a crucial role in the relentless drive towards miniaturization at the nanometre scale
