Applied Metamaterials

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EPJ D Colloquium - Two-dimensional laser-induced fluorescence in the gas phase: a spectroscopic tool for studying molecular spectroscopy and dynamics

Two-dimensional laser-induced fluorescence (2D-LIF) extends the usual laser-induced fluorescence technique by incorporating a second dimension, namely the wavelengths at which the excited molecules emit, thereby significantly enhancing the information that can be extracted. It allows overlapping absorption features, whether they arise from within the same molecule or from different molecules in a mixture, to be associated with their appropriate "parent" state and/or molecule.

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EPJ A Highlight - From experiment to evaluation, the case of n+238U

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Evaluated nuclear data represent the bridge between experimental and theoretical achievements and final user applications. The complex evolution from experimental data towards final data libraries forms the cornerstone of any evaluation process. Since more than 90% of the fuel in most nuclear power reactors consists of 238U, the respective neutron induced cross sections are of primary importance towards accurate neutron transport calculations. Despite this significance, the relevant experimental data for the 238U(n,γ) capture reaction have only recently provided for a consistent description of the resonance region. In this work, the 238U(n,γ) average cross sections were evaluated in the energy region 5-150 keV, based on recommendations by the IAEA Neutron Standards projects and experimental data not included in previous evaluations.

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EPJ Plus Highlight - Ice shapes the landslide landscape on Mars

Landslides on Mars

SA new study uses a combination of glacial morphology and remote sensing measurement to explore the role of ice in shaping Martian landslides

How good is your Martian geography? Does Valles Marineris ring a bell? This area is known for having landslides that are among the largest and longest in the entire solar system. They make the perfect object of study due to their steep collapse close to the scarp, extreme thinning, and long front runout. In a new research paper published in EPJ Plus, Fabio De Blasio and colleagues from Milano-Bicocca University, Italy, explain the extent to which ice may have been an important medium of lubrication for landslides on Mars. This can in turn help us understand the geomorphological history of the planet and the environment of deposition.

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EPJ Data Science Highlight - Gaining historical and international relations insights from social media

As more and more people get their news from social media platforms, these become hosts to vast amounts of information on human behavior in relation to real-time events around the world. In a study published in EPJ Data Science, Vanessa Peña-Araya and team successfully match geopolitical interactions obtained from Twitter activity with real-world historical international relations.

(Guest post by Vanessa Peña-Araya, Mauricio Quezada, Denis Parra and Barbara Poblete, originally published on the SpringerOpen blog

Online social media platforms, like Twitter, Sina Weibo, or Facebook, have become very popular in recent years. They are primarily used to share personal experiences and to keep in touch with friends. Nevertheless, many users turn to these platforms as reliable sources to find real-time information about world events, such as the Ukrainian Crisis or recent natural disasters. In particular, Twitter has become one of the prefered sources on the Web for breaking news updates

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EPJ Data Science Highlight - Out in the city with Pokémon Go

In the summer of 2016 Pokémon Go took the world by storm. Millions of people across the globe descended on their streets, searching their neighbourhoods for monsters. Much has been reported on the health benefits that players gained from using the app; now, research published in EPJ Data Science explores how Pokémon Go was able to change the pulse of a city, encouraging people to use areas in ways they didn't previously.

(Guest post by Eduardo Graells-Garrido, originally published on SpringerOpen blog

The success of Pokémon Go is undeniable. People of all ages and everywhere in the world were using their mobile phones to go around their cities trying to catch the next pocket monster. But “PoGo” had an interesting, perhaps unintended, side-effect: not only did the game let you catch Pokémon in an augmented reality (AR) environment, it also motivated players to walk more and meet new people.

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EPJ Plus Highlight - Remote sensing for cosmic dust and other celestial bodies

How to bring an asteroid back nearer to lunar orbit. Credits: Keck Institute for Space Studies report

Study reviews the state-of-the-art in polarimetry as a remote sensing technique for the small bodies in our solar system

The solar system is full of various small bodies such as planetary moons, main belt asteroids, Jupiter Trojans, Centaurs, trans-Neptunian objects and comets. To study them, scientists typically analyse the radiation they reflect, which is referred to as polarimetry. Scientists not only focus on the intensity of the scattered radiation, but also on how photons oscillate in the plane perpendicular to their direction of propagation - that is, their polarisation. Combining these two aspects yields significantly better descriptions than data obtained from the intensity alone. In a paper published in EPJ Plus, Stefano Bagnulo from Armagh Observatory and Planetarium in Northern Ireland, UK, and colleagues review the state-of-the-art in polarimetry for studying the small bodies in our solar system.

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EPJ E Highlight - Resolving tension on the surface of polymer mixes

Polymers © iker-urteaga via Unsplash.

A new study finds a simple formula to explain what happens on the surface of melted mixes of short- and long-strand polymers

Better than playing with Legos, throwing polymer chains of different lengths into a mix can yield surprising results. In a new study published in EPJ E, physicists focus on how a mixture of chemically identical chains into a melt produces unique effects on their surface. That’s because of the way short and long polymer chains interact with each other. In these kinds of melts, polymer chain ends have, over time, a preference for the surface. Now, Pendar Mahmoudi and Mark Matsen from the University of Waterloo, Ontario, Canada, have studied the effects of enriching long-chain polymer melts with short-chain polymers. They performed numerical simulations to explain the decreased tension on the surface of the melt, due to short chains segregating at the surface over time as disorder grows in the melt. They found an elegant formula to calculate the surface tension of such melts, connected to the relative weight of their components.

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EPJ E Highlight - The secret to improving liquid crystal's mechanical performance

3D plot of the concentration of nanoparticles around a moving edge dislocation in a smectic A liquid crystal.

Better lubricating properties of lamellar liquid crystals could stem from changing the mobility of their structural dislocations by adding nanoparticles

By deliberately interrupting the order of materials - by introducing different atoms in metal or nanoparticles in liquid crystals - we can induce new qualities. For example, metallic alloys like duralumin, which is composed of 95% of aluminium and 5% copper, are usually harder than the pure metals. This is due to an elastic interaction between the defects of the crystal, called dislocations, and the solute atoms, which form what are referred to as Cottrell clouds around them. In such clouds, the concentration of solute atoms is higher than the mean concentration in the material. In a paper published in EPJ E, Patrick Oswald from the École Normale Supérieure of Lyon, France, and Lubor Lejček from the Czech Academy of Sciences have now theoretically calculated the static and dynamical properties of the Cottrell clouds, which form around edge dislocations in lamellar liquid crystals of the smectic A variety decorated with nanoparticles. This work could be important, for example, in the context of improving the lubricating performance of such liquid crystals.

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EPJ D Highlight - Quantum manipulation power for quantum information processing gets a boost

Relationship between the output power and the number of photons.

Improving the efficiency of quantum heat engines involves reducing the number of photons in a cavity, ultimately impacting quantum manipulation power

Traditionally, heat engines produce heat from the exchange between high-temperature and low-temperature baths. Now, imagine a heat engine that operates at quantum scale, and a system made up of an atom interacting with light (photons) confined in a reflective cavity of sub-atomic dimensions. This setup can either be at a high or low temperature, emulating the two baths found in conventional heat engines. Controlling the parameters influencing how such quantum heat engine models work could dramatically increase our power to manipulate the quantum states of the coupled atom-cavity, and accelerate our ability to process quantum information. In order for this to work, we have to find new ways of improving the efficiency of quantum heat engines. In a study published in EPJ D, Kai-Wei Sun and colleagues from Beihang University, Beijing, China, show methods for controlling the output power and efficiency of a quantum thermal engine based on the two-atom cavity. In the familiar heat engine model at macroscopic scale, referred to as the Carnot heat engine, the efficiency increases as a function of the ratio between the temperatures of the low-and high-temperature baths. By comparison, the efficiency of two-level quantum heat engines is related to the level of quantum entanglement in these two states, which are either at a low or a high temperature, and display the same probability of being occupied.

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EPJ Plus Highlight - Best tactical approach to handling patients with simultaneous parasitic and HIV infection

Cryptosporidiosis
Copyright © 2012 Michael Bonert.
You are free to share and adapt this image as per the CC BY-SA 3.0.

New mathematical model for cryptosporidiosis - HIV co-infection explores their synergistic relationship in connection with prevention and treatment

One of the most common waterborne diseases worldwide is cryptosporidiosis, a parasitic disease affecting the small intestine and possibly our airways. It is a common cause of diarrhoea in HIV-positive patients, who are known to have lower immunity. Now Kazeem Oare Okosun from Vaal University of Technology in South Africa and colleagues from Pakistan and Nigeria have developed a new model and numerical simulations to determine the optimal combination of prevention and treatment strategies for controlling both diseases in patients who have been co-infected. Their results, recently published in EPJ Plus, show a positive impact on the treatment and prevention for cryptosporidiosis alone, for HIV-AIDS alone, or for both together.

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Editor-in-Chief
Yang Hao
ISSN (Electronic Edition): 2272-2394

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