About EPJ

The European Physical Journal (EPJ) is a series of peer-reviewed journals covering the whole spectrum of physics and related interdisciplinary subjects. EPJ is committed to high scientific quality in publishing and is indexed in all main citation databases.

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EPJ B Highlight - Nanoscale heat flow predictions
Tuesday, 22 April 2014 12:02
Snapshot of the final configuration of a nc-Si sample. © Melis et al.

A new study predicts that heat flow in novel nanomaterials could contribute to creating environmentally friendly and cost-effective nanometric-scale energy devices

Physicists are now designing novel materials with physical properties tailored to meet specific energy consumption needs. Before these so-called materials-by-design can be applied, it is essential to understand their characteristics, such as heat flow. Now, a team of Italian physicists has developed a predictive theoretical model for heat flux in these materials, using atom-scale calculations. These findings, published in EPJ B by Claudio Melis and colleagues from the University of Cagliary, Italy, could have implications for optimising the thermal budget of nanoelectronic devices—which means they could help dissipate the total amount of thermal energy generated by electron currents—or in the production of energy through thermoelectric effects in novel nanomaterials.

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EPJ B Highlight - Grasp of SQUIDs dynamics facilitates eavesdropping
Tuesday, 08 April 2014 09:29
Average voltage output of a DC SQUID under varying conditions. © Berggren et al.

Latest theoretical advances pertaining to the dynamics of highly sensitive magnetometers could find military applications in low-noise amplifiers and sensitive antennas

Theoretical physicists are currently exploring the dynamics of a very unusual kind of device called a SQUID. This Superconducting Quantum Interference Device is a highly sensitive magnetometer used to measure extremely subtle magnetic fields. It is made of two thin regions of insulating material that separate two superconductors – referred to as Josephson junctions – placed in parallel into a ring of superconducting material. In a study published in EPJ B, US scientists have focused on finding an analytical approximation to the theoretical equations that govern the dynamics of an array of SQUIDs. This work was performed by Susan Berggren from the US Navy research lab, SPAWAR Systems Center Pacific, in San Diego, CA, USA and Antonio Palacios San Diego State University. Its applications are mainly in the military sector, including SQUID array-based low-noise amplifiers and antennas.

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EPJ E - Andreas Bausch, the new biological physics EiC
Monday, 07 April 2014 16:01
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This month EPJE welcomes Andreas Bausch, who takes over from Frank Jülicher, as Editor in Chief for biological physics in EPJ E – Soft Matter and Biological Physics. In his lab, Bausch applies new experimental tools of soft condensed matter physics to living cells and bio-mimetic model systems. This is his vision for biological physics within EPJE in the years to come:

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EPJ B Highlight - Graphene nanoribbons as electronic switches
Monday, 31 March 2014 12:32
© Credit: Dmitry Knorre/Fotolia

A new theoretical study shows the conductivity conditions under which graphene nanoribbons can become switches in externally controlled electronic devices

One of graphene’s most sought after properties is its high conductivity. Argentinian and Brazilian physicists have now successfully calculated the conditions of the transport, or conductance mechanisms, in graphene nanoribbons. The results, recently published in a paper in EPJ B, yield a clearer theoretical understanding of conductivity in graphene samples of finite size, which have applications in externally controlled electronic devices.

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EPJ E Highlight - Making the most of carbon nanotube-liquid crystal combos
Wednesday, 26 March 2014 09:28
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Dispersed multi-wall carbon nanotubes on a glass surface. © Yakemseva et al.

A better understanding of the physical response of combination materials made of nanotubes with ferroelectric liquid crystals could soon open the door to applications as sensors or switches

Dispersions of carbon nanotubes with liquid crystals have attracted much interest because they pave the way for creating new materials with added functionalities. Now, a study published in EPJ E by Marina Yakemseva and colleagues at the Nanomaterials Research Institute in Ivanovo, Russia, focuses on the influence of temperature and nanotube concentration on the physical properties of such combined materials. These findings could have implications for optimising these combinations for non-display applications, such as sensors or externally stimulated switches, and novel materials that are responsive to electric, magnetic, mechanical or even optical fields.

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EPJ E Topical Review: Foaming experiments on the ISS
Monday, 24 March 2014 15:38
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The ISS

Foams and foaming processes pose interesting questions for both fundamental research and practical applications. Although foams are a familiar thing, both in our everyday lives and in industry, many aspects of foam physics and chemistry still remain unclear.

This EPJ E paper comprehensively reviews the studies of foams under microgravity, including studies conducted in parabolic flights, in sounding rockets and in the International Space Station.

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EPJ D Highlight - Plasma tool for destroying cancer cells
Tuesday, 11 March 2014 14:05
The plasma discharged used to study DNA at ambient air conditions. © Han et al.

Inducing biological tissue damage with an atmospheric pressure plasma source could open the door to many applications in medicine

Plasma medicine is a new and rapidly developing area of medical technology. Specifically, understanding the interaction of so-called atmospheric pressure plasma jets with biological tissues could help use them in medical practice. Under the supervision of Sylwia Ptasinska from the University of Notre Dame, in Indiana, USA, Xu Han and colleagues conducted a quantitative and qualitative study of the different types of DNA damage induced by atmospheric pressure plasma exposure, in a paper published in EPJ D as part of a special issue on nanoscale insights into Ion Beam Cancer Therapy. This approach, they hope, could ultimately lead to devising alternative tools for cancer therapy as well as applications in hospital hygiene, dental care, skin diseases, antifungal care, chronic wounds and cosmetics treatments.

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EPJB Colloquium – From SiC to fluorescent SiC based white LEDs
Tuesday, 11 March 2014 13:44
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Three free standing 3C-SiC substrates with size 10x10 mm (Fig. 16).

A new EPJ B Colloquium reviews the latest advances in silicon carbide (SiC) for optoelectronics. The wide bandgap of SiC makes it a great semiconductor material to make devices for in high power, high frequency and high temperature applications.

During the past decade, SiC has also become a promising materials for light-emitting diodes (LED), since it was found that co-doping it with nitrogen and boron produces a high donor-acceptor pair emission efficiency. Fluorescent SiC based white LED light source is an innovative concept for optoelectronic devices.

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EPJB Review - New promising bulk thermoelectrics
Tuesday, 11 March 2014 10:05
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Superlattice structure of (BiS)1.2(TiS2)2 misfit layer sulfide. (Fig. 15).

The growing need for alternative “green” energy sources has prompted renewed interest in thermoelectric materials. These materials can directly convert heat to electricity or, conversely, use electrical current to cool. The thermoelectric performance of a material can be estimated by the so-called figure of merit, zT = σα2T/λ (α is the Seebeck coefficient, σα2 is the power factor, σ and λ are the electrical and thermal conductivity, respectively), the value of which depends only on the material.

In a new EPJ B review, authors Gonçalves and Godart discuss the state of the art in this field, with special emphasis on the strategies to reduce the lattice part of the thermal conductivity and maximize the power factor in thermoelectric materials.

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EPJ B Highlight - Football displays fractal dynamics
Wednesday, 05 March 2014 13:00
Players’ and ball’s positions captured on video. © Kijima et al.

Physicists reveal that the real-time dynamics in a football game are subject to self-similarity characteristics in keeping with the laws of physics, regardless of players’ psychology and training

Football fascinates millions of fans, all of them unaware that the game is subject to the laws of physics. Despite their seemingly arbitrary decisions, each player obeys certain rules, as they constantly adjust their positions in relation to their teammates, opponents, the ball and the goal. A team of Japanese scientists has now analysed the time-dependent fluctuation of both the ball and all players’ positions throughout an entire match. They discovered that a simple rule governs the complex dynamics of the ball and the team’s front-line. These findings , published in EPJ B, could have implications for other ball games, providing a new perspective on sports science.

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EPJ D Topical Review: Self-assembling and self-limiting monolayer deposition
Wednesday, 26 February 2014 09:45

The effect of spatial ordering of molecules on surfaces is commonly utilised to deposit ultra-thin films, where the film thickness is only a few nanometres. In this EPJ D review paper, several methods are discussed that are distinguished from other thin film deposition processes by exactly these effects, leading to self-assembling and self-limiting layer growth and, eventually, to coatings with unique and fascinating properties, and applications in micro-electronics, optics, chemistry, and biology.

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EPJ H Highlight - All paths lead to Rome, even the path to condensed matter theory
Wednesday, 26 February 2014 09:23
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Carlo Di Castro. © 2004 Humboldt Prize

Italian physicist Carlo Di Castro shares his thoughts on the development of theoretical condensed matter physics in Rome from the 1960s until the beginning of this century.

Italian physicist Carlo Di Castro, professor emeritus at the University of Rome Sapienza, Italy, shares his recollections of how theoretical condensed matter physics developed in Rome, starting in the 1960s. Luisa Bonolis, a researcher at the Max Planck Institute for the History of Science in Berlin, Germany invited Di Castro to reflect upon his research career, which he did in an interview published in EPJ H.

In this unique document, Di Castro talks about his upbringing during the second World War. He also explains how this childhood experience later influenced his philosophy, which he aptly summarises as follows: “the fear of the unknown must be overcome through knowledge and reason.” Ultimately, this approach guided the career choices that led him to become a condensed matter physicist.

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EPJ D Highlight - Patterns of interfering massive particles
Wednesday, 26 February 2014 08:44
The continuous microwave beam ejects atoms from the trap at a slow rate. © P. Sancho

A new study represents a step forward in our understanding of the nature of exchange interactions between identical particles, which only occur at the quantum level

Two-particle interference has been the focus of many studies, specifically in quantum optics with photons. However, interference between two massive, identical particles is not so well understood. In a study published in EPJ D, Pedro Sancho from the CLPU—Centre for Pulsed Lasers—in Salamanca, Spain, uncovers a counterintuitive result whereby particles called bosons do not behave as expected—they are overlapping, and not interfering—due to the combination of interference and so-called exchange interaction. The latter is a quantum mechanical effect that alters their symmetry when identical particles are exchanged.

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EPJ Plus Highlight - Carbon dating uncovers forged Cubist painting
Wednesday, 19 February 2014 13:02
The alleged Contraste de formes, an oil on canvas from the Peggy Guggenheim Collection, Venice, was proven to be a fake. © Caforio et al.

Physicists use carbon dating to confirm alleged Fernand Léger painting was definitely a fake, thus corroborating the doubts about its authenticity previously expressed by art historians

Choosing the right physical technique to analyse paintings can make all the difference when it comes to ascertaining their authenticity. Now, a painting initially attributed as belonging to a series called ‘Contraste de formes’ by French Cubist painter Fernand Léger has definitely been identified as a forgery. This is the first time it has been possible to identify a fake painting by relying on the anomalous behaviour of the concentration of the radioactive form of carbon (14C) in the atmosphere after 1955 to date the canvas. These findings were recently published in EPJ Plus by Mariaelenea Fedi of the National Institute of Nuclear Physics (INFN) in Florence, Italy, and colleagues.

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EPJ Plus Highlight - Scaling up renewable energy
Wednesday, 19 February 2014 08:08
Power increments of the grid measured every 15 minutes, against the initial grid power for solar power. © F. Wagner

A new study focuses on the feasibility of scaling up renewable energy to cover the needs of a country the size of Germany

Can renewable energy adequately supply the power grid, despite its intermittent nature? This is the key question in a new study published in EPJ Plus. The study is based on an analysis of concrete data from 2012 for the German national grid, which also utilises electricity from both on and offshore wind (8%) and solar sources (4.8%). Friedrich Wagner from the Max-Planck Institute for Plasma Physics in Greifswald, Germany, outlines the key issues associated with the use of renewable energy on a large scale.

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EPJ B Highlight - Probing the edge of chaos
Tuesday, 18 February 2014 15:19
Fractals. © wajakaa - Photolia

To understand natural phenomena with a chaotic nature, the key is to find out how their variable physical characteristics behave at the very point preceding the onset of chaos

The edge of chaos—right before chaos sets in—is a unique place. It is found in many dynamical systems that cross the boundary between a well-behaved dynamics and a chaotic one. Now, physicists have shown that the distribution—or frequency of occurrence—of the variables constituting the physical characteristics of such systems at the edge of chaos has a very different shape than previously reported distributions. The results have been published in EPJ B by Miguel Angel Fuentes from the Santa Fe Institute in New Mexico, USA, and Universidad del Desarrollo, Chile, and Alberto Robledo from the National Autonomous University of Mexico, Mexico City. This could help us better understand natural phenomena with a chaotic nature.

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EPJ B Highlight - Optimising custody is child’s play for physicists
Tuesday, 11 February 2014 09:02
A graph depicting the children’s custody problem, where grey nodes represent couples. © Gomberoff et al.

Ensuring that parents in recomposed families see their children regularly is a complex network problem that models developed to study materials may help to solve

Physics can provide insights into societal trends. Problems involving interactions between people linked in real-life networks can be better understood by using physical models. As a diversion from his normal duties as a theoretical physicist, Andrés Gomberoff from the Andres Bello University, in Santiago, Chile, set out to resolve one of his real-life problems: finding a suitable weekend for both partners in his recomposed family to see all their children at the same time. He then joined forces with a mathematician and a complex systems expert. This resulted in a study published in EPJ B, showing that solving this problem essentially equates to minimising the energy in a material model.

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EPJ H Highlight - Einstein’s forgotten model of the universe
Wednesday, 05 February 2014 16:57
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An image of the blackboard used in Einstein’s 2nd Rhodes lecture at Oxford in April 1931. © Museum of the History of Science, University of Oxford, UK

New insights into Einstein’s view of the cosmos from the translation and study of one of his least known papers

A paper published in EPJ H provides the first English translation and an analysis of one of Albert Einstein’s little-known papers, “On the cosmological problem of the general theory of relativity”. Published in 1931, it features a forgotten model of the universe, while refuting Einstein’s own earlier static model of 1917. In this paper, Einstein introduces a cosmic model in which the universe undergoes an expansion followed by a contraction. This interpretation contrasts with the monotonically expanding universe of the widely known Einstein-de Sitter model of 1932.

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EPJ H Highlight - Einstein’s conversion from a static to an expanding universe
Wednesday, 05 February 2014 16:43
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Einstein and Lemaître photographed around 1933. © Archives Lemaître, Université Catholique, Louvain

Albert Einstein accepted the modern cosmological view that the universe is expanding, only long after several of his contemporaries had demonstrated it with astrophysical observations

Until 1931, physicist Albert Einstein believed that the universe was static. An urban legend attributes this change of perspective to when American astronomer Edwin Hubble showed Einstein his observations of redshift in the light emitted by far away nebulae—today known as galaxies. But the reality is more complex. The change in Einstein’s viewpoint, in fact, resulted from a tortuous thought process. Now, in an article published in EPJ H, Harry Nussbaumer from the Institute of Astronomy at ETH Zurich, Switzerland, explains how Einstein changed his mind following many encounters with some of the most influential astrophysicists of his generation.

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EPJ A Highlight - MINOS: A vertex tracker coupled to a thick liquid-hydrogen target for in-beam spectroscopy of exotic nuclei
Wednesday, 05 February 2014 15:39
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View of the MINOS device inside the DALI2 gamma array at the RIKEN Radioactive Isotope Beam Factory.

MINOS is a new apparatus dedicated to in-beam nuclear structure experiments with low-intensity exotic beams at energies above 150 MeV/nucleon.

It is intended to provide increased luminosity compared to standard solid-target experiments in hydrogen-induced studies, while simultaneously improving experimental resolution. This article exposes the concept of the device developed at the CEA in France and reviews in detail the associated recent technical advances. MINOS is composed of a thick finger-shaped liquid hydrogen target, from 50 to 200 mm thick, combined with a compact time projection chamber serving as a vertex tracker, the first of its kind in low-energy nuclear physics. This innovative setup offers access to the first spectroscopy of a new range of very exotic nuclei beyond our current reach. An exciting program on the search for new 21+ states in neutron-rich even-even nuclei, spectroscopy of unbound oxygen nuclei and di-neutron correlations in borromean nuclei will be performed with MINOS at the RIKEN Radioactive Isotope Beam Factory in Japan over the next few years. MINOS is funded by the European Research Council.

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EPJ B Highlight - Bottom-up insight into crowd dynamics
Tuesday, 04 February 2014 16:47
In the simulations, agents are grouped into six zones based on their initial distances from the exit. © Viswanthan et al.

A new study proposes a method for quantitatively analysing the relative value of models for crowd dynamics prediction, following individual movement

Stampedes unfortunately occur on too regular a basis. Previously, physicists developed numerous models of crowd evacuation dynamics. Their analyses focused on disasters such as the yearly Muslim Hajj or of the Love Parade disaster in Germany in 2010. Unfortunately, the casualties at these events may have been linked to the limitations of the crowd dynamics models used at the time. Now, a new study outlines a procedure for quantitatively comparing different crowd models, which also helps to compare these models with real-world data. In a paper published in EPJ B, Vaisagh Viswanathan, a PhD student from Nanyang Technological University in Singapore, and colleagues have demonstrated that these crowd evacuation dynamics models are a viable decision-making tool in safety preparation and planning concerning real-world human crowds.

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EPJ Quantum Technology – A new Open-Access Journal is launched
Friday, 31 January 2014 06:37
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The publishers are pleased to announce the launch of a new open-access journal in the EPJ series – EPJ Quantum Technology. The journal has just gone live, with three research papers already available.

Driven by advances in technology and experimental capability, the last decade has seen the emergence of quantum technology: a new praxis for controlling the quantum world. It is now possible to engineer complex, multi-component systems that merge the once distinct fields of quantum optics and condensed matter physics.

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EPJ E Highlight - Towards tailor-made adhesives
Friday, 24 January 2014 07:11
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View of the cavitation process, with blue contours representing the borders of the cavities. © Tanguy et al.

The inner structure of soft adhesive materials during the debonding process is, for the first time, under scrutiny in the hope of producing new, improved adhesives in the future

Tape, self-adhesive labels, Post-it notes and masking tape all contain soft adhesives. This makes them easy to remove—a process referred to as debonding. French scientists have studied how soft adhesives work in the hope of facilitating the design of more efficient adhesives. Francois Tanguy, a researcher at ESPCI ParisTech, the School of Industrial Physics and Chemistry, in Paris, France, and colleagues have, for the first time, performed a precise analysis of the material deformation and structure during the course of debonding for several model adhesives. Their findings are published in EPJ E. By better understanding the connection between the energy dissipated by the polymeric material with adhesive qualities and its response to traction, they hope to improve models of adhesive performance.

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EPJ B Colloquium - Thermodynamics and kinetics properties of condensed matter derived through the properties of an intrinsic defect
Friday, 24 January 2014 06:42
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Elementary jump of an interstitialcy in an fcc Lattice. Open circles (red), before jump; closed circles (blue), after jump (Fig. 6 from the paper).

The theory of interstitialcy for simple condensed matters is a theory formulated by Andrew V. Granato enable the determination of the thermodynamic and kinetic properties of simple liquids and glasses. In a new Colloquium in EPJ B the author provides a simpler, more physical and compelling version of his interstitialcy theory. In addition, the results of computer simulations, together with direct and indirect experimental evidence, are updated and reviewed. In addition, the results of computer simulations, together with direct and indirect experimental evidence, are updated and reviewed. The connection between theory and experiment for some of the more notable properties of simple condensed matter is discussed. The direct visual observation of interstitial diffusion to the surface of irradiated platinum thin films near 20K by Morgenstern, Michely and Comsa provides compelling evidence for the interstitialcy theory presented herein.

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EPJ B Highlight - Quasi-particle swap between graphene layers
Tuesday, 21 January 2014 10:08
Sketch of the two twisted graphene layers. © M. Sarrazin et al.

Equations used to describe parallel worlds in particle physics can help study the behaviour of particles in parallel graphene layers

Belgian scientists have used a particle physics theory to describe the behaviour of particle-like entities, referred to as excitons, in two layers of graphene, a one-carbon-atom-thick honeycomb crystal. In a paper recently published in EPJ B, Michael Sarrazin from the University of Namur, and Fabrice Petit from the Belgian Ceramic Research Centre in Mons, studied the behaviour of excitons in a bilayer of graphene through an analogy with excitons evolving in two abstract parallel worlds, described with equations typically used in high-energy particle physics.

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EPJ C goes Open Access funded by SCOAP3
Wednesday, 01 January 2014 19:52

As of January 2014, The European Physical Journal C – Particles and Fields will be published as full open access journal funded by SCOAP3. One of the leading journals in the field, EPJ C was selected to participate in this initiative - lead by CERN with the support of partners in 24 countries - which will make a vast fraction of scientific articles in the field of High-Energy Physics open access at no cost for any author. Moreover authors will retain copyright and creative commons licenses will enable wide re-use of the published material.

 
EPJ E Highlight - Elucidating biological cells’ transport mechanisms
Wednesday, 18 December 2013 14:56
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Image of mitochondria observed by transmission electron microscopy. © K. Hayashi et al.

A new study focuses on the motion of motor proteins in living cells, applying a physicist’s tool called non-equilibrium statistical mechanics

Motion fascinates physicists. It becomes even more intriguing when observed in vivo in biological cells. Using an ingenious setup, Japanese scientists have now calculated the force of molecular motors acting on inner components of biological cells, known as organelles. In this study, the focus is on mitochondria—akin to micrometric range cellular power plants—travelling along microtubules in a cell. Published in EPJ E by Kumiko Hayashi, from Tohoku University, Sendai, Japan, these findings could contribute to elucidating the transport mechanism in biological cells by multiple motors.

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EPJ D Highlight - How hypergravity impacts electric arcs
Monday, 16 December 2013 14:06
Glide arc discharge under normal gravity conditions. © J. Sperka et al.

A new study focused on electric discharge behaviour under intense gravitational forces shows that its dynamic changes as gravity increases

Arc discharges are common in everyday conditions like welding or in lightning storms. But in altered gravity, not as much is known about the behaviour of electric discharges. For the first time, Jiří Šperka from Masaryk University, Czech Republic, and his Dutch colleagues studied the behaviour of a special type of arc discharge, so-called glide arc, in varying hypergravity conditions, up to 18 G. In a paper just published in EPJ D, they demonstrate how the plasma channel of this glide arc discharge moves due to external forces of buoyancy in varying gravity conditions. These results could have implications for improved safety precautions in manned space flights, and in the design of ion thrusters used for spacecraft propulsion.

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EPJE Colloquium - Electrification of wind-blown sand
Wednesday, 11 December 2013 13:45
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A new Colloquium in EPJE by Xiao-Jing Zheng introduces and reviews the fundamental laws of the electrification of wind-blown sand and their influence, and highlights the challenges in this field.

The electrification of wind-blown sand is a typical complex system characterised by nonlinearity, randomness, multi-field coupling between thermal diffusion, E-fields and sand movements, as well as trans-scale processes with multi-phase media. Owing to the complex mechanism and the influence of the electrification of wind-blown sand [19], a number of issues remain poorly understood. These include: (1) why sand particles get charged during wind-blown sand movements; (2) how many electric charges a sand particle acquires; (3) why the electric polarity of sand particles is related to the particles’ size; (4) what the change law of wind-blown sand E-fields is, and (5) how to predict the intensity and influence of wind-blown sand E-fields.

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EPJ D Highlight - Sharpening the focus in quantum photolithography
Wednesday, 11 December 2013 13:28
© Tambako the Jaguar/Flickr

A new protocol, exploiting the quantum properties of materials, makes it possible to improve the accuracy of photolithography by addressing its physical limitations due to diffraction

Photolithography uses light beams to design thin geometric patterns on the substrates of semiconductors used in microelectronic devices. This is achieved using a chemical reaction on a light-sensitive chemical, called photoresist. The trouble is that the phenomenon of light diffraction does not permit highly accurate patterns. Often, the edges of stripes have low contrast, the distances between the stripes and the stripes’ width are limited by what is referred to as Rayleigh’s diffraction limit. Now, a scientist from Russia has developed a quantum lithography protocol designed to improve the resolution of this technology. The findings of George Miroshnichenko, a physicist at Saint-Petersburg National Research University of Information Technologies, Mechanics and Optics, in Russia, have just been published in EPJ D.

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