Today, Johnson Publishing announced the launch of a digital store for its EBONY and JET brands where readers can buy a variety of content and branded merchandise.EbonyJetShop.com features streaming audio and video, downloadable music and videos and access to archived, proprietary content dating back to 1942. Additionally, visitors will be able to purchase branded Johnson Publishing products like t-shirts, mugs, fashion accessories and other content like cookbooks and e-books. Cheryl Mayberry McKissack suggests that it is another step in digitizing the Johnson stable, which shuttered its print edition of JET months ago, replacing it with a higher-frequency digital edition. “According to a recent Nielsen study, African-Americans are 14 percent more likely to spend time on telecom/internet service sites and 21 percent more likely to spend time on lifestyle sites than the total market,” she says in an official company statement. “We want to meet our consumers where they are.”
Movement of the Dirac points. Image (c) Nature, doi:10.1038/nature10871 Citation: Research team finds way to simulate graphene Dirac points (2012, March 15) retrieved 18 August 2019 from https://phys.org/news/2012-03-team-simulate-graphene-dirac.html In an interesting turn of events, another team taking a completely different approach has also managed to find a way to show the existence of Dirac points and to manipulate them as well by synthesizing a form of graphne and arranging it in the familiar chicken-wire lattice on top of a conducting substrate and then manipulating it with a tunneling microscope. They have also published their results in Nature.Finding ways to show how Dirac points can be manipulated will help to find ways of using graphene in real world applications that could result in new exotic materials with unique electronic properties, leading to end products that in some cases can’t even be imagined yet. Explore further The secrets of tunneling through energy barriers Now, Tilman Esslinger and his fellow researchers at the Institute for Quantum Optics at ETH Zurich have found a way to do just that by simulating graphene and its properties using a laser created lattice filled with potassium-40 atoms. They report on their findings in the journal Nature.The experiment began by cooling potassium-40 atoms, leaving them lethargic so they wouldn’t move away from within the lattice. Their role was to serve as stand-ins for electrons moving in graphene. Then, to create the lattice, the team fired one laser perpendicular to another causing the two to interfere with each other. A third laser beam with a slightly different wavelength was then added to create a standing wave. In this scenario, the square lattice that resulted could be adjusted by adjusting the third beam. The team then tested the lattice for Dirac points by speeding up the atoms and measuring their trajectories and found two of them by noting the momentum between the lattice cells didn’t slow, meaning there wasn’t any gap. Better yet, the team found that by adjusting the lattice they could manipulate the Dirac points, moving them around or even causing them to disappear completely. The density distribution of the potassium atoms measured after acceleration through Dirac points (left and centre), and without Dirac point (right). The upper row shows the corresponding regions of the calculated bandstructure. (Image: Tilman Esslinger’s Research Group / ETH Zurich) © 2011 PhysOrg.com More information: Creating, moving and merging Dirac points with a Fermi gas in a tunable honeycomb lattice, Nature 483, 302–305 (15 March 2012) doi:10.1038/nature10871AbstractDirac points are central to many phenomena in condensed-matter physics, from massless electrons in graphene to the emergence of conducting edge states in topological insulators. At a Dirac point, two energy bands intersect linearly and the electrons behave as relativistic Dirac fermions. In solids, the rigid structure of the material determines the mass and velocity of the electrons, as well as their interactions. A different, highly flexible means of studying condensed-matter phenomena is to create model systems using ultracold atoms trapped in the periodic potential of interfering laser beams. Here we report the creation of Dirac points with adjustable properties in a tunable honeycomb optical lattice. Using momentum-resolved interband transitions, we observe a minimum bandgap inside the Brillouin zone at the positions of the two Dirac points. We exploit the unique tunability of our lattice potential to adjust the effective mass of the Dirac fermions by breaking inversion symmetry. Moreover, changing the lattice anisotropy allows us to change the positions of the Dirac points inside the Brillouin zone. When the anisotropy exceeds a critical limit, the two Dirac points merge and annihilate each other—a situation that has recently attracted considerable theoretical interest but that is extremely challenging to observe in solids10. We map out this topological transition in lattice parameter space and find excellent agreement with ab initio calculations. Our results not only pave the way to model materials in which the topology of the band structure is crucial, but also provide an avenue to exploring many-body phases resulting from the interplay of complex lattice geometries with interactions.Press release (PhysOrg.com) — As researchers continue to study graphene and its unique attributes, they find themselves fixated on different areas of its properties. One of those properties is that because of its lattice structure, graphene is a “zero-gap” semiconductor. This means that its conduction and electron valance bands actually touch each other at certain points, which means there is no energy gap between them, as is the case with current semiconductor materials. And this means that the momentum and energy association is very much like that of photons, which implies that electrons could move at speeds approaching the speed of light. These parts of graphene’s structure are known as Dirac points. Up until now though, no one has been able to see any real world evidence of such points, much less manipulate them. Journal information: Nature This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Enroll Now for Free This hands-on workshop will give you the tools to authentically connect with an increasingly skeptical online audience. This story originally appeared on Fortune Magazine 3 min read Free Workshop | August 28: Get Better Engagement and Build Trust With Customers Now Today’s automobiles now come loaded with software and sensors that can help drivers navigate the roads more safely and even do away with the need to have human drivers at all.However, this world of connected vehicles involving on board computers collecting and transmitting data about location, speed, and engine performance also leads to a much more insecure automobile landscape.This is why the Alliance of Automobile Manufacturers (AAM)—an alliance of twelve automakers including Ford, General Motors, and Mercedes-Benz—said Tuesday that it is creating an information sharing and analysis center (ISAC). This center will let participating companies swap cyber security data and keep each other abreast of the latest hacking threats targeting vehicles.The organization said that the new center will be up and running later on this year, and that it will be distributing cyber threat information to the automakers involved with the hub. The goal is to “further enhance the industry’s ongoing efforts to safeguard vehicle electronic systems and networks,” explained Robert Strassburger, vice president for vehicle safety at the AAM, in a statement.As the threat-sharing hub matures, the AAM expects that other companies related to vehicle manufactures—such as auto part suppliers, telecommunication providers, and even tech companies—will join the hub.Google has been busy developing its own self-driving car, so one would imagine the hub would like to tap into any security related information the tech giant might have that could help car companies.Consulting firm Booz Allen Hamilton was selected to help the AAM develop the center. The auto organization is also asking the government to help out by including “legal protections that facilitate cyber security information sharing,” explained Strassburger.President Obama has recently called for companies and government agencies to swap security related informationto help prevent cyber attacks. Additionally, a couple of cyber security bills were recently created to encourage the private and public sector to exchange security data. Both bills support the idea of a government-sanctioned threat-exchange hub and would offer some sort of legal protection for companies willing to swap data in case any privacy-related lawsuits emerge.Considering how regulated auto manufacturers are, it’s probable a given that they expect the government to get involved with their new threat-sharing hub somehow.Whether tech companies like Google, Facebook, or Apple choose to participate remains to be seen. The tech industry has made it clear that it doesn’t want the government to participate in any data-swapping initiative they may be involved with.Additionally, carmakers have made it clear that they want to limit the amount of data like engine and braking information they share with tech companies like Google and Apple so only they can be the ones holding valuable data that could improve their bottom line. July 15, 2015