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.
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 , 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.
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.
The alleged shortcomings of quantum theory do not hold up to scrutiny, as the theory proves sound for the prediction of probability of events connected to the fate of sub-atomic scale particles
A colloquium paper published in EPJ D peers into the alleged issues associated with quantum theory. Berthold-Georg Englert from the National University of Singapore reviews a selection of the potential problems of the theory. In particular, he looks into cases when mathematical tools are confused with the actual observed sub-atomic scale phenomena they are describing. Such tools are essential to provide an interpretation of the observations, but cannot be confused with the actual object of studies.
A new study demonstrates that electrical resistivity obeys a staircase-like dependence on the conducting particle concentration in composite materials
Composite materials are of increasing interest to physicists. Typically, they are made of electrically conducting elements - such as spherical metallic or elongated carbon particles - embedded in an insulating glass or a polymer matrix. Their controllable electrical resistivity combined with their light and flexible properties, makes them suited for applications in flexible electronics. Now, a theoretical model, confirmed experimentally, elucidates how electrical resistivity varies with the concentration of the particles in these composite materials. These findings have been published in EPJ B, by Isaac Balberg and colleagues from the Hebrew University in Jerusalem, Israel.
New calculations shows that the influence of quantum effects on the operating conditions of nanodevices has, until now, been overestimated
Micro- and nano-electromechanical devices, referred to as MEMS and NEMS, are ubiquitous. These nanoscale machines with movable parts are used, for example, to trigger cars’ airbags following a shock. They can also be found in smartphones, allowing them to detect how to adequately display the screen for the viewer. The trouble is that, as their size decreases, forces typically experienced at the quantum level start to matter in these nanodevices. Mexican physicists have studied the mechanical and electrical stability of MEMS and NEMS, depending on the plate thickness and the nature of the material used. The results have now been published in EPJ B by Raul Esquivel-Sirvent and Rafael Perez-Pascual from the National Autonomous University of Mexico, in Mexico City.
No better solution to studying ever-draining foams than applying a strong magnetic field to keep the liquid in the foam at a standstill by levitating its water molecules
Foams fascinate, partly due to their short lifespan. Foams change as fluid drains out of their structure over time. It is precisely their ephemeral nature which has, until now, prevented scientists from experimentally probing their characteristic dynamics further. Instead, foams have often been studied theoretically. Now, Nathan Isert from the University of Konstanz, Germany and colleagues, have devised a method of keeping foams in shape using a magnet, which allows their dynamics to be investigated experimentally, as recently described in EPJ E.
Numerical simulations designed to confirm the magnetic characteristics of 3D quantum materials largely match the theoretical predictions
A new study set out to use numerical simulations to validate previous theoretical predictions describing materials exhibiting so-called antiferromagneting characteristics. A recently discovered theory shows that the ordering temperature depends on two factors—namely the spin-wave velocity and the staggered magnetisation. The results, largely consistent with these theoretical predictions, have now been published in a paper in EPJ B by Ming-Tso Kao and Fu-Jiun Jiang from the National Taiwan Normal University, in Taipei.
First study to shows specific sounds’ speed and attenuation characteristics in liquid foam, opens the door to new type of sound proofing material
Liquid foams fascinate toddlers singing in a bubble bath. Physicists, too, have an interest in their acoustical properties. Borrowing from both porous material and foam science, Juliette Pierre from the Paris Diderot University, Paris, France and her colleagues studied liquid foams. They used an impedance tube to measure the velocity and attenuation of acoustic waves in liquid foams in a broad frequency range. The study published in EPJ E is a first in the literature. It could help in assessing any liquid foam’s bubble size or in designing the optimal foam structure for sound proofing.
Fusion is one of the holy grails of energy production. Now, theoretical physicists have used simulations to investigate the uniformity of irradiation at the ignition stage of thermonuclear fusion reaction.
One of the ways to achieve thermonuclear fusion is through a controlled reaction between two light variants of hydrogen, called deuterium and tritium. Mauro Temporal, from the École Normale Supérieure Cachan, in France, and colleagues have made theoretical calculations indicating how best to improve the ignition stage of fusion reaction. Their approach, described in a paper published in EPJ D, involves increasing the uniformity of irradiation using high-power laser beams on the external shell of a spherical capsule containing a mix of deuterium and tritium.
How fluid dynamics and transport shaped the structure of our lungs in the course of evolution.
Two French physicists, Bernard Sapoval and Marcel Filoche from École Polytechnique in Palaiseau, France, suggest in a study published in EPJ E how evolution has shaped our lungs through successive optimisations of physical parameters such as conservation of energy and speed of delivery.
This EPJ B Colloquium presents an overview of the preparation method and physical properties of a new hybrid system consisting of single-walled carbon nanotubes (SWNTs) wrapped in conjugated polymers. The technique, which was first demonstrated in 2007, has attracted great interest owing to the high purity of the resulting semiconducting SWNTs and the possibility of applying them in electronic devices. Here, the authors review recent progress in the preparation of these nano-hybrids, their photophysical properties, and their applications in field-effect transistors and photovoltaic devices.
This EPJD colloquium describes an approach whereby the effect of low and intermediate energy (0-100 eV) electrons and positrons can be incorporated into radiation damage models, in particular the deceleration of these particles in biologically-relevant materials (water and representative biomolecules). At the heart of the modelling procedure is a C++ computer program called Low Energy Particle Track Simulation (LEPTS), which is compatible with commonly available general purpose Monte Carlo packages. Input parameters are carefully selected from theoretical and experimental cross-section data and energy loss distribution functions.
A new simulation will help improve artificial sand-control measures designed to help combat desertification by identifying their weaknesses
In the fight against desertification, so-called straw checkerboard barriers (SCB), consisting of half -exposed criss-crossing rows of straw of wheat, rice, reeds, and other plants, play a significant role. The trouble is that our understanding of the laws governing wind-sand movement in SCB and their surrounding area is insufficient. Now, Ning Huang and colleagues from Lanzhou University in China, have performed a numerical simulation of the sand movement inside the SCB, described in a paper just published in EPJ E. Their country is particularly affected by desertification, which affects 18% of its territory. The results will help us to understand sand fixation mechanisms that are relevant for sandstorm and land-desertification control.
A new manipulation tool exploits the fact that when light interacts with matter, it creates a force that produces material properties in macromolecules and biological cells
Romanian scientists have discovered a novel approach for the optical manipulation of macromolecules and biological cells. Their findings stem from challenging the idea that visible light would induce no physical effect on them since it is not absorbed. Instead, Sorin Comorosan, working as physicist at the National Institute for Physics and Nuclear Engineering based in Magurele, Romania, and as a biologist at the Fundeni Clinical Institute, Bucharest, Romania, and colleagues had the idea to use green photon beams. With them, it is possible to perform optical manipulation of macrostructures, such as biological proteins, with greater precision than with optical tweezers made from focused laser beams.
Nuclear fission is accompanied by the prompt emission of neutrons, gamma rays and x-rays. It has been known since the sixties that fission prompt x-rays originate essentially as a consequence of the internal conversions occurring in the prompt gamma deexcitation cascades of fission fragments.
This work presents for the first time a measurement of the prompt fission x-ray yields in 238U(n,f) for average incident neutron energies ranging from 3 to 200 MeV. These results provide new information on fission fragment deexcitation and allow testing the current knowledge of fission fragment nuclear structure. These results provide also a means to investigate the evolution, as a function of incident neutron energy, of fission fragment charge yields and elemental prompt x-ray emission probabilities.
New research outlines a new design of spatio-temporal models of astrophysical plasmas
The birth of stars is an event that eludes intuitive understanding. It is the collapse of dense molecular clouds under their own weight that offers the best sites of star formation. Now, Pralay Kumar Karmakar from the Department of Physics at Tezpur University, Assam province, India, and his student have proposed a new model for investigating molecular clouds fluctuations at sites of star formation and thus study their pulsational dynamics, in a paper just published in EPJ D.
New research gives a theoretical explanation as to how transport of single atoms is made possible through a chain of quantum dots
Scientists have pushed back the boundaries of atom-based transport, creating a current by charac-terising the many-body effects in the transport of the atoms along a periodic lattice. This work by Anton Ivanov and colleagues from the Institute for Theoretical Physics, at the University of Heidel-berg, Germany, adopted a new analytical approach before comparing it to approximate numerical simulations, and is reported in a paper recently published in EPJ B.
Professor Yeomans has been nominated for her profound contribution to the study of the dynamical behaviour of complex and active liquids in confined geometries. She is an expert in theoretical and computational physics, particularly statistical physics, hydrodynamics, soft condensed matter and biological physics. Among her current research interests are microswimmers, active systems, liquid crystals and the interactions of fluids with structured surfaces.
Scientists can now theoretically construct atomic beams of a particular kind, opening the door for applications in fields like quantum communication.
Physicists have, for the first time, now built a theoretical construct of beams made of twisted atoms. These findings are about to be published in EPJ D by Armen Hayrapetyan and colleagues at Ruprecht-Karls-University Heidelberg in Germany. These so-called atomic Bessel beams can, in principle, have potential applications in quantum communication as well as in atomic and nuclear processes.
The electromagnetic polarisabilities of the nucleons characterise their responses to external fields. The simplest are the electric and magnetic polarisabilities that describe the induced dipole moments. For spin-1/2 particles there are also four spin polarisabilities, analogous to rotations of the polarisation of light by optically active media. The best experimental window on them is Compton scattering of photons, which has provided good determinations of the electric and magnetic polarisabilities of the proton. Future experiments with polarised protons will give access to its spin polarisabilities. In contrast, much less is known of about the neutron since it does not exist as a stable target. Nonetheless, its properties can be obtained from Compton scattering on light nuclei, most notably the deuteron -- a weakly bound proton and neutron. A new generation of experiments is planned to provide beams of polarised photons on targets of polarised deuterons. If the spins of the final particles are not observed, there are 18 independent observables. This work provides, for the first time, the complete set of these, which will be needed for the experimental analyses. More importantly, it also examines their sensitivities to the various polarisabilities, which will be crucial for the design of the experiments.
Physicists can use their tools to help understand how, in real life, opinions form and change by modelling the complex interactions between information and emotion
Social phenomena fascinate with their complexity, but are not easily understood. Pawel Sobkowicz, an independent researcher based in Warsaw, Poland, has developed a model to study the dynamic of standard people, called ‘agents’, and their response to a given piece of information, depending on their emotional state. In a study just published in EPJ B, the author shows that opinion dynamics differ depending on whether the agent is agitated or not.
Drug designers now have a new way of designing drug candidates suitable for dislodging unstable water molecules located in the defects at the surface of target proteins
New research shows a physical characterisation of the interface of the body’s proteins with water. Identifying the locations where is it easiest to remove water from the interface of target proteins could constitute a novel drug design strategy. The candidate drugs would need to be engineered to bind at the site of the protein where interfacial water is most easily dislodged. These findings, based on the work of María Belén Sierra from the National University of the South, in Bahia Blanca, Argentina and colleagues, recently published in EPJ E.
Study uncovers the effects of size variation in nanoscale blocks used in polymer mixes on their underlying architecture and inherent characteristics
Building structures by mixing lego bricks of two different sizes is child’s play. However, studying polymers endowed with an alternating nanostructure made of heterogeneous blocks is anything but straightforward. Theoretical physicist Mark Matsen, based at the University of Reading, UK, studies polymer mixes consisting of two-fold (AB) and three-fold (BAB) combinations of two types of nanoscale blocks. He has shown, in a study published in EPJ E, that the underlying heterogeneity of the blocks can cause polymers to switch to different nanoscale patterns and therefore display different properties. Numerous applications based on etching patterns on substrates, such as electronics, computer chips, and membranes endowed with a specific function, can benefit from such research.
Sheets of biological cells move along the organs they cover by altering the external concentrations of specific molecules, thanks to an absorption mechanism on the cells’ surface
What do wound healing, cancer metastasis, and bacteria colonies have in common? They all involve the collective displacement of biological cells. New research sheds some new light on the physical mechanisms provoking the displacement of a sheet of cell, known as an epithelium. It typically covers our organs including the stomach and intestine, as well as our epidermis. In a paper which appeared in EPJ E, Martine Ben Amar from Pierre and Marie Curie University in Paris explains the importance of understanding the displacement of the epithelium as a means of influencing the biological process involved in healing. And, ultimately, of helping to minimise scars.
Understanding complexity in the early universe may require combining simpler models to interpret cosmological observations
Complicated statistical behaviour observed in complex systems such as early universe can often be understood if it is broken down into simpler ones. Two physicists, Petr Jizba (currently affiliated with the Czech Technical University in Prague), and Fabio Scardigli (now working at Kyoto University in Japan), have just published results in EPJ C pertaining to theoretical predictions of such cosmological systems’ dynamics.
Polarisability for series of multi-electron ions is now available
Polarisability determines the force with which an inhomogeneous external electric field acts on the ions of an ion beam. However, it can be quite tricky to obtain accurate values for this force. Now, two German theoretical chemists, Volker Koch from Bielefeld University and Dirk Andrae from the Free University Berlin, have devised formulas providing the polarisability of atomic ions as a function of their total charge number. Their findings, about to be published in EPJ D, have implications for many applications, ranging from the use of ion beams for research purposes or as a source for dopant atoms in semiconductor manufacturing to the modelling of planetary and stellar atmospheres.
Study shows that the order of events taking place in complex networks may dramatically alter the way diffusion occurs
The Internet, motorways and other transport systems, and many social and biological systems are composed of nodes connected by edges. They can therefore be represented as networks. Scientists studying diffusion over such networks over time have now identified the temporal characteristics that affect their diffusion pathways. In a paper just published in EPJ B, Renaud Lambiotte and Lionel Tabourier from the University of Namur, Belgium, together with Jean-Charles Delvenne from the Catholic University of Louvain, Belgium, show that one key factor that can dramatically change a diffusion process is the order in which events take place in complex networks.
It is now possible to identify the meaning of words with multiple meanings, without using their semantic context
Two Brazilian physicists have now devised a method to automatically elucidate the meaning of words with several senses, based solely on their patterns of connectivity with nearby words in a given sentence – and not on semantics. Thiago Silva and Diego Amancio from the University of São Paulo, Brazil, reveal, in a paper just published in EPJ B, how they modelled classics texts as complex networks in order to derive their meaning. This type of model plays a key role in several natural processing language tasks such as machine translation, information retrieval, content analysis and text processing.
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.
The release of the journal Impact Factors (IF) by Thomson Reuters confirms once more the position of EPJ as a premium provider of relevant and strictly peer-reviewed research in the physical sciences and beyond. We are especially proud of the fast-paced development of our newer journals: EPJ Plus, launched only in 2011, was already awarded its first IF (1.302) and EPJ H – Historical Perspectives in Contemporary Physics, launched in 2010, progressed from an IF of 1.182 in 2011 to an impressive 2.375 for 2012.
The full overview of 2012 EPJ Impact Factors is given here.