- Published on 25 April 2018
Tuning the graphene embedded in a photonic crystal by varying the external temperature can transform it into a light-sensitive sensor
Graphene has many properties; it is e.g. an extremely good conductor. But it does not absorb light very well. To remedy this limiting aspect of what is an otherwise amazing material, physicists resort to embedding a sheet of graphene in a flat photonic crystal, which is excellent for controlling the flow of light. The combination endows graphene with substantially enhanced light-absorbing capabilities. In a new study published in EPJ B, Arezou Rashidi and Abdolrahman Namdar from the University of Tabriz, Iran demonstrate that, by altering the temperature in such a hybrid cavity structure, they can tune its capacity for optical absorption. They explain that it is the thermal expansion and thermo-optical effects which give the graphene these optical characteristics. Potential applications include light sensors, ultra-fast lasers, and systems capable of modulating incoming optical beams.
EPJ Data Science Highlight - Discovering temporal regularities in retail customers’ shopping behaviour
- Published on 18 April 2018
Why do we buy certain items when we buy them? A new study published in EPJ Data Science analyzes personal retail data to extract a temporal purchasing profile, which is able to summarize whether and when a customer makes a purchase. Its results show that certain patterns and types of shoppers are detectable, which can be used both by customers to enable personalized services, and by the retail market chain for providing offers and discounts tailored to the individual shoppers personal temporal profile.
(Guest post by Riccardo Guidotti and Anna Monreale, originally published on the SpringerOpen blog)
- Published on 16 April 2018
Personal recollections of an astrophysicist shed new light on the 1995 discovery on 51 Pegasi b
In recent history, a very important achievement was the discovery, in 1995, of 51 Pegasi b, the first extrasolar planet ever found around a normal star other than the Sun. In a paper published in EPJ H, Davide Cenadelli from the Aosta Valley Astronomical Observatory (Italy) interviews Michel Mayor from Geneva Observatory (Switzerland) about his personal recollections of discovering this exoplanet. They discuss how the development of better telescopes made the discovery possible. They also delve into how this discovery contributed to shaping a new community of scholars pursuing this new field of research. In closing, they reflect upon the cultural importance that the 51 Pegasi b discovery had in terms of changing our view of the cosmos.
- Published on 10 April 2018
(This post was originally published on the SpringerOpen blog)
A team of researchers from Northeastern University, Boston, used a big data approach to investigate what makes a book successful. By evaluating data from the New York Times Bestseller Lists from 2008 to 2016, they developed a formula to predict if a book would be a bestseller.
- Published on 10 April 2018
With the goal of understanding and modelling the reactive dissolution of solids, new microscopic methods have been developed for the investigations of the phenomena and kinetics of these reactions, and applied to the dissolution of uranium dioxide in nitric acid media.
The first paper presents a state of knowledge of the dissolution of uranium dioxide in nitric acid media. It highlights the numerous chemical and physico-chemical issues which still need to be addressed concerning its understanding, with a focus on autocatalysis, mass-transport and non-uniform attack of the solids.
- Published on 28 March 2018
Colloidal model featuring rigid bodies with two interaction sites explains how biological entities such as protein/DNA combinations can self-assemble
What makes particles self-assemble into complex biological structures? Often, this phenomenon is due to the competition between forces of attraction and repulsion, produced by electric charges in various sections of the particles. In nature, these phenomena often occur in particles that are suspended in a medium - referred to as colloidal particles - such as proteins, DNA and RNA. To facilitate self-assembly, it is possible to "decorate" various sites on the surface of such particles with different charges, called patches. In a new study published in EPJ E, physicists have developed an algorithm to simulate the molecular dynamics of these patchy particles. The findings published by Silvano Ferrari and colleagues from the TU Vienna and the Centre for Computational Materials Science (CMS), Austria, will improve our understanding of what makes self-assembly in biological systems possible.
- Published on 27 March 2018
A new review highlights the historical developments in our understanding of the nuclear structure of unstable and unbound forms of helium, lithium and beryllium
Research into the origin of elements is still of great interest. Many unstable atomic nuclei live long enough to be able to serve as targets for further nuclear reactions - especially in hot environments like the interior of stars. And some of the research with exotic nuclei is, for instance, related to nuclear astrophysics. In this review published in EPJ A, Terry Fortune from the University of Pennsylvania, in Philadelphia, USA, discusses the structure of unstable and unbound forms of Helium, Lithium, and Beryllium nuclei that have unusually large neutron to proton ratios - dubbed ‘exotic’ light nuclei. The author offers an account of historical milestones in measurements and the interpretation of results pertaining to these nuclei.
- Published on 21 March 2018
Thinnest-ever silicon crystal enhances ion channelling performance in particle accelerators
The thinner the silicon crystal, the better. Indeed, thinner crystals provide better ways to manipulate the trajectories of very high-energy ions in particle accelerators. Further applications include materials analysis, semiconductor doping and beam transport in large particle accelerators. All of these rely on our understanding of how positively-charged high-energy particles move through crystals. This process, called ion channelling, is the focus of a new paper by Mallikarjuna Motapothula and Mark Breese working at the National University of Singapore. In a paper published in EPJ B, the authors study how the crystal periodicity affects the motion of ions whose energy belongs to a 1 to 2 MeV range, as they are transmitted through very thin crystals on the order of a few hundred nanometres, and how it impacts their angular distribution.
- Published on 09 March 2018
In this new article in EPJ D, Franke et al. review the present understanding of Lamb shift, fine- and hyperfine structure of the 2S and 2P states in muonic helium-3 ions in anticipation of the results of the first measurements of several 2S -> 2P transition frequencies in the muonic helium-3 ion, 3He+. This ion is the bound state of a single negative muon μ- and a bare helium-3 nucleus (helion), 3He++.
- Published on 07 March 2018
The “Focus Point on the Transition to Sustainable Energy Systems” in the European Physical Journal Plus (EPJ Plus) tries to answer central questions regarding the planned Energy Transition, focusing on the power sector in Europe. Important is the role played by intermittent renewables as a low carbon electricity source, central in the plans by the EU Commission in its Energy Roadmap 2050. Their intermittency however strongly reduces efficiency and security of supply and back up by other systems is unavoidable – large storage and/or nuclear and/or fossil based. Storage of excess electricity production by intermittent renewables at the level required seems far-fetched at this moment and much more research will be needed before this can substantially contribute. With a limited contribution of dispatchable renewable electricity (hydro, bio-fuels etc.) and excluding à priori nuclear power, on various grounds, a continued use of fossil fuels imposes itself to guarantee a secured supply of electricity – in strong contrast with the original aims of the EU Energy Roadmap 2050. A rational debate involving all options is urgently needed and it is hoped that the set of papers in this focus point can contribute to improve insights in a determining factor for the future of our children and grandchildren.