- Published on 01 July 2013
A new study shows how specific parameters can help us steer clear of tipping points in dynamic systems, such as entire economies.
By managing macro-economic parameters, scientists believe that—unlike previously thought—it is possible to steer an economy around irreversible changes in its complex dynamics and avert potential economic disasters. These findings, just published in EPJ B, stem from the theoretical work of Michael Harré and colleagues at the Complex Systems Group at the University of Sydney, Australia.
- Published on 18 June 2013
A team of Chinese scientists evaluates the impact of a website based on the interaction between its users with the entire Web
A new study shows that small websites, in terms of daily user flux based on number of clicks, have a disproportionally high impact when it comes to traffic generation and influence compared to larger websites. These findings, just published in EPJ B, have implications for estimating the value of sites and related advertising revenue. They result from the work of Lingfei Wu from the City University of Hong Kong and Jiang Zhang from the School of Management, at Beijing Normal University, China.
- Published on 05 June 2013
Model demonstrates that it is possible for two particles to cross an energy barrier together, where a single particle could not
For the first time, a new kind of so-called Klein tunnelling—representing the quantum equivalent of crossing an energy wall— has been presented in a model of two interacting particles. This work by Stefano Longhi and Giuseppe Della Valle from the Institute of Photonics and Nanotechnology in Milan, Italy, has just been published in EPJ B.
Klein tunnelling is a quantum phenomenon referring to the fact that a high-potential barrier can be transparent to a particle moving at a speed nearing that of light, referred to as relativistic. Most of the previous Klein tunnelling models describe the phenomenon for a single particle. However, when two particles are involved, tunnelling can be modified as a result of their mutual interaction. This means, for example, that two electrons hopping on a lattice, or two ultra-cold atoms trapped in an optical lattice can exchange energy when they occupy the same lattice site.
- Published on 17 May 2013
A new study discusses the electric and magnetic characteristics of a material which could be used in spintronics
Materials belonging to the family of dilute magnetic oxides (DMOs) — an oxide-based variant of the dilute magnetic semiconductors — are good candidates for spintronics applications. This is the object of study for Davide Sangalli of the Microelectronics and Microsystems Institute (IMM) at the National Research Council (CNR), in Agrate Brianza, Italy, and colleagues. They recently explored the effect of iron (Fe) doping on thin films of a material called zirconia (ZrO2 oxide). For the first time, the authors bridged the gap between the theoretical predictions and the experimental measurements of this material, in a paper just published in EPJ B.
- Published on 10 April 2013
Studying the effect of migration on cooperation could help to better understand social cohesion
Migrations happen for a reason, not randomly. A new study, based on computer simulation, attempts to explain the effect of so-called directional migration – migration for a reason – on cooperative behaviours and social cohesion. These results appear in a study just published in EPJ B by Hongyan Cheng from Beijing University of Posts and Telecommunications and colleagues.
- Published on 02 April 2013
This EPJB Colloquium reviews the pioneering studies of plasmon resonance in heavily doped semiconductor thin ﬁlms. It also reports the chemical synthesis and structural properties of heavily doped semiconductor nanocrystals. Their linear plasmonic response (under excitation with weak continuous-wave optical ﬁelds) is illustrated both theoretically and experimentally. Finally, the authors review the most recent results on the transient (i.e. nonlinear) ultrafast plasmonic features exhibited by chalcogenide nanocrystals under excitation with ultra-fast optical pulses, including a “gold-like” theoretical model. This model turns out to provide suﬃcient insights into the ﬁrst experiments on heavily-doped plasmonic nanoparticles.
Plasmonics in heavily-doped semiconductor nanocrystals. Francesco Scotognella et al., Eur. Phys. J. B (2013) 86: 154, DOI: 10.1140/epjb/e2013-40039-x
- Published on 27 March 2013
A new study of animal swarms uncovers some new features of their collective behaviour when overcrowding sets in
Swarming is the spontaneous organised motion of a large number of individuals. It is observed at all scales, from bacterial colonies, slime moulds and groups of insects to shoals of fish, flocks of birds and animal herds. Now physicists Maksym Romenskyy and Vladimir Lobaskin from University College Dublin, Ireland, have uncovered new collective properties of swarm dynamics in a study just published in EPJ B. Ultimately, this could be used to control swarms of animals, robots, or human crowds by applying signals capable of emulating the underlying interaction of individuals within the swarm, which could lead to predicted motion patterns elucidated through modelling.
- Published on 17 March 2013
Work on a high-conductivity material demonstrates the role of oxygen ions in enhancing their capabilities
Yttria stabilized zirconia, also known as YSZ, is a material of great interest because of its relatively high oxygen-ion based conductivity. In particular, it finds applications in electrochemical devices, such as solid oxide fuel cells and oxygen sensors. In a study published in EPJ B, Kia Ngai, from the University of Pisa in Italy, and colleagues from the Complutense University in Madrid, Spain, devised a model of the oxygen-ion dynamics that contribute to the conductivity of YSZ.
- Published on 23 February 2013
A new approach is available for real-time monitoring of the structural health of wind turbine components during exposure to turbulences.
Physicists have now developed a new method for analysing the elastic characteristics of mechanical structures subjected to disturbances, akin to the turbulences affecting wind turbines. These results have just been published in EPJ B by Philip Rinn and his colleagues at the ForWind Center for Wind Energy Research at the University of Oldenburg, Germany.
A significant percentage of the costs of wind energy is due to wind turbine failures, as components are weakened under turbulent air flow conditions and need to be replaced. The challenge for the team was to find a method for detecting fatigue in the wind turbines’ parts without having to remove each of the components and while the turbine is in operation.
- Published on 10 February 2013
Varying magnetic fields and temperature conditions help to elucidate smart materials’ transitory magnetic disorder
Novel, smart materials like shape memory alloys very often display so-called glass-like magnetism. Other smart materials with similar properties include those which, when exposed to a magnetic field, change their electrical resistance, known as manganites, or change their temperature, known as magnetocaloric materials. Kaustav Mukherjee and his colleagues from the Consortium for Scientific Research Indore in India studied a key stage in the formation of such a magnetic glass material, called Pr0.5 Ca0.5 Mn0.975 Al0.025 O3, in a paper just published in EPJ B.