Currently most ultrasound devices convert an electrical signal directly into mechanical vibrations through the piezoelectric effect. But these devices only operate over a narrow frequency range and have limited output. The idea of using heat to generate sound has been around for over 80 years, but until recently the thermal conduction of porous silicon was […]
The medium is made of nanocrystals of zinc sulphide doped with samarium. Although the nanocrystals are only 3 nanometres long, they clump together into larger particles to form a powder that can be used as the storage medium. In their experiments Kurita and co-workers used a laser to measure the energy excitation spectrum of the […]
Colloidal plasmas contain three different components – electrons, ions and charged microspheres. Although these unusual plasmas can be studied in the laboratory, researchers have only been able to study two-dimensional effects because gravity can overwhelm the electrostatic interactions between the particles. These interactions are responsible for the unusual properties of colloidal plasmas. By reducing the […]
Inside a pulsar the neutrons are thought to decay into protons and electrons, which are then accelerated by the pulsar’s powerful magnetic field. Since protons and electrons are charged particles, they release intense synchrotron radiation at radio wavelengths from the magnetic poles of the pulsar. Previously astronomers believed that once a pulsar slowed beyond a […]
Read article: A double-slit experiment in a single molecule
Photons from the laser can excite electrons in the water molecules into a so-called anti-bonding state. Molecules in this state can adopt one of two distorted shapes, both of which can dissociate into a hydroxide radical and a hydrogen atom. However the two different shapes can result in the hydroxide radical being created in different […]
An earlier report from the National Research Council has already expressed concern that the US may not retain its leadership in science and technology. The report speculated that the supply of foreign researchers moving to the US could dry up as the world’s economy improves. The report concluded that more US students had to be […]
Neptune’s ring arcs were first observed by the Voyager spacecraft in 1984. In the absence of some external source of stability the rings would have been expected to decay within a matter of months. But the three rings – called Liberté, Egalité and Fraternité – are still visible, and it has been assumed that their […]
Supersymmetry is an attractive theory to physicists as it provides a connection between all known elementary particles and can simplify many complex interactions. High energy supersymmetry suggests that instead of two types of basic elementary particles – bosons and fermions – there is just one. It also implies that high-energy physics experiments should detect twice […]
Parisi won the award for his work in a wide number of fields. The official citation highlights “his study of scaling violations in deep inelastic processes (Altarelli-Parisi equations), a model that links supersymmetry and superconductors together, the introduction of multifractals equations into turbulence studies, the stochastic differential equation for growth models for random aggregation (the […]
At the age of two, John Desmond Bernal was taken by his American mother from their farm in Ireland to see his grandmother in California. He amazed other passengers on the steamship by talking in both English and French. Later on, when he was at Cambridge, his fellow undergraduates would nickname him “Sage” because of […]
