Nuclear Sciences & Technologies

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EPJ Plus Highlight - Smart multi-layered magnetic material acts as an electric switch

The structure of ultrathin films of a cobalt nickel alloy.

New study reveals characteristic of islands of magnetic metals between vacuum gaps, displaying tunnelling electric current

The nanometric-size islands of magnetic metal sporadically spread between vacuum gaps display unique conductive properties under a magnetic field. In a recent study published in EPJ Plus, Anatoliy Chornous from Sumy State University in Ukraine and colleagues found that the vacuum gaps impede the direct magnetic alignment between the adjacent islands - which depends on the external magnetic field - while allowing electron tunneling between them. Such externally controlled conducting behaviour opens the door for applications in electronics with magnetic field sensors - which are used to read data on hard disk drives - biosensors and microelectromechanical systems (MEMS), as well as in spintronics with magnetic devices used to increase memory density.

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EPJ AP Highlight - Training for the first international nano-car race

A 3 step driving along the Au(111) track. The black cross indicates the tip position for the inelastic tunneling excitation of the Dresden molecule-vehicle.

The first international nano-car race will be held in Toulouse, France, during spring 2017, with the participation of six international teams. The training session of the Dresden Team is reported here.

To prepare their participation, Eisenhut et al. exercised on the Toulouse LT-UHV 4-STM reconfigured for the race with 4 independent controllers (one per scanning tunneling microscope (STM)). Their findings are reported in EPJ AP.

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EPJ D Highlight - Novel plasma jet offshoot phenomenon explains blue atmospheric jets

Example of the apokamp effect in a plasma jet.

Russian physicists identify mysterious right-angle side-jet occurring off the plasma arc in air at ambient pressure conditions

Ionised matter, like plasma, still holds secrets. Physicists working with plasma jets, made of a stream of ionised matter, have just discovered a new phenomenon. Indeed, Eduard Sosnin from the Institute of High Current Electronics, Russian Academy of Sciences in Tomsk, Russia, and colleagues found a new type of discharge phenomenon in an atmospheric pressure plasma. It has been dubbed apokamp—from the Greek words for ‘off’ and ‘bend’, because it appears at a perpendicular angle to where plasma jets bend. Their findings have been recently published in EPJ D and are particularly relevant for the development of novel applications in medicine, health care and materials processing because they involve air at normal atmospheric pressure, which would make it cheaper than applications in inert gases or nitrogen.

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EPJ E Highlight - Nanoparticles hitchhiking their way along strands of hair

Corrugated hair surface.

Massaging hair can help more quickly deliver nanoparticle-based treatment to the roots

In shampoo ads, hair always looks like a shiny, smooth surface. But for physicists peering into microscopes, the hair surface looks much more rugged, as it is made of saw-tooth, ratchet-like scales. In a new theoretical study published in EPJ E, Matthias Radtke and Roland Netz have demonstrated that massaging hair can help to apply drug treatment - encapsulated in nanoparticles trapped in the channels formed around individual hairs - to the hair roots. This is because the oscillatory movement of the massaging directs the way these particles are transported.

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EPJ Plus Highlight - 100% renewable energy sources require overcapacity

Germany's greenhouse gas (GHG) emissions from 2002 to 2015 and the political target for 2020 (bars).

To switch electricity supply from nuclear to wind and solar power is not so simple

Germany decided to go nuclear-free by 2022. A CO2-emission-free electricity supply system based on intermittent sources, such as wind and solar - or photovoltaic (PV) - power could replace nuclear power. However, these sources depend on the weather conditions. In a new study published in EPJ Plus, Fritz Wagner from the Max Planck Institute for Plasma Physics in Germany analysed weather conditions using 2010, 2012, 2013 and 2015 data derived from the electricity supply system itself, instead of relying on meteorological data. By scaling existing data up to a 100% supply from intermittent renewable energy sources, the author demonstrates that an average 325 GW wind and PV power are required to meet the 100% renewable energy target. This study shows the complexity of replacing the present primary energy supply with electricity from intermittent renewable sources, which would inevitably need to be supplemented by other forms of CO2-free energy production.

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EPJ E Highlight - How water can split into two liquids below zero

Representation of the diamond lattices formed by the particle studied.

Theoretical possibility of the coexistence of dual liquid states of matter in sub-zero water due to the origami-like stacking behaviour of microscale moleculesy

Did you know that water can still remain liquid below zero degrees Celsius? It is called supercooled water and is present in refrigerators. At even smaller temperatures, supercooled water could exist as a cocktail of two distinct liquids. Unfortunately, the presence of ice often prevents us from observing this phenomenon. So physicists had the idea of replicating the tetrahedral shape of water molecules - using DNA as a scaffold to create tetrahedral molecules - and thus removing the interference of ice formation. This approach allowed Simone Ciarella from the University of Rome, Italy, and his colleagues to confirm that, in theory, a dual liquid phase is possible in sub-zero water and any other liquids made of tetrahedral molecules. These results have been published in EPJ E. It is a great tale of how the underlying microscopic shape determines the overall macroscopic form.

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EPJ ST Highlight - Champagne owes its taste to the finely tuned quality of its bubbles

Flower-shaped structure, frozen through high-speed photography, found during the collapse of bubbles at the surface of a champagne flute.

What provides the wonderful aromas is a long neuro-physico-chemical process that results in bubbles fizzing at the surface of champagne

Ever wondered how the fate of champagne bubbles from their birth to their death with a pop enhances our perception of aromas? These concerns, which are relevant to champagne producers, are the focus of a special issue of EPJ Special Topics, due to be published in early January 2017 - celebrating the 10th anniversary of the publication. Thanks to scientists, champagne producers are now aware of the many neuro-physico-chemical mechanisms responsible for aroma release and flavour perception. The taste results from the complex interplay between the level of CO2 and the agents responsible for the aroma - known as volatile organic compounds - dispersed in champagne bubbles, as well as temperature, glass shape, and bubbling rate.

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EPJ ST Highlight - Economics made simple with physics models

Snapshot of the study of economic phenomena using the tools of physics

How would you go about understanding how markets can suddenly be gripped by panic? To physicists, using a model originally developed to explain magnetism might make sense. Yet, economists may find this extremely counter-intuitive. Both physical and economic phenomena may possess universal features that could be uncovered using the tools of physics. The principal difference is that in economic systems - unlike physical ones - current actions may be influenced by the perception of future events. The latest issue of EPJ Special Topics examines the question as to whether econophysics, a physics-based approach to understanding economic phenomena, is more useful and desirable than conventional economics theories.

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EPJ AP Highlight - Silicon Plasma Wave Receiver for Terahertz Wireless Communication

The signal to noise ratio (SNR) of the Si-CMOS receiver versus modulation frequency of the 300GHz carrier. The inset shows the block diagram with the main components: the patch antenna, the plasma wave FET, with schematically shown damped plasma oscillations, and the integrated wide-band amplifiers chain.

This paper presents the design, manufacturing and characterization of an integrated circuit (IC) that uses the plasma oscillations phenomena in silicon nanotransistors (Si-CMOS) for the detection of a 300 GHz-carrier-frequency wireless signal. We present the strategies for a Si-CMOS-based, wideband, integrated circuit receiver comprising: (i) a physics based, specific plasma-wave-transistor design, allowing impedance matching to the antenna and the amplifier, (ii) a patch antenna engineered through a stacked resonator approach and (iii) a broadband amplifier that uses bandwidth enhancement circuit techniques.

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EPJ AP Highlight - Emergent gain materials for active photonics

Example of an optical waveguide containing colloidal quantum dots. When the nanostructures are optically pumped the waveguide propagates and confines the photoluminescence. Above a certain threshold light is amplified.

Nowadays semiconductor nanostructures developed by colloidal methods have emerged as an alternative to the classical III-V semiconductors and rare earth technologies to provide active functionalities in photonic devices. Their outstanding optical properties include high absorption cross section, high quantum yield of emission at room temperature, or the capability of tuning the band-gap with the size/base material. As a consequence, these materials have been successfully applied in several fields, such as photodetection, amplification, generation of light or sensing. For these purposes their solution process nature provides a cheap fabrication, and an easy incorporation on a broad range of substrates and photonic structures. This review summarizes the great effort undertaken by the scientific community to construct active photonic devices based on semiconductors fabricated by chemical methods. The works compares the performances demonstrated by semiconductor nanocrystals (colloidal quantum dots, quantum rods and quantum wells) with those provided by organometal halide perovskites, and describes their appropriate integration into photonic architectures (waveguides and cavities) to achieve stimulated emission.

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Editors-in-Chief
G. Moutiers and A. Nicolas
ISSN: 2491-9292 (Electronic Edition)

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