Science

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New lithium-oxygen battery greatly improves energy efficiency, longevity: New chemistry could overcome key drawbacks of lithium-air batteries

Lithium-air batteries are considered highly promising technologies for electric cars and portable electronic devices because of their potential for delivering a high energy output in proportion to their weight. But such batteries have some pretty serious drawbacks: They waste much of the injected energy as heat and degrade relatively quickly. They also require expensive extra components to pump oxygen gas in and out, in an open-cell configuration that is very different from conventional sealed batteries.

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In a new concept for battery cathodes, nanometer-scale particles made of lithium and oxygen compounds (depicted in red and white) are embedded in a sponge-like lattice (yellow) of cobalt oxide, which keeps them stable. The researchers propose that the material could be packaged in batteries that are very similar to conventional sealed batteries yet provide much more energy for their weight.

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X Marks the Spot for Milky Way Formation

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Researchers used data from NASA's Wide-field Infrared Survey Explorer (WISE) mission to highlight the X-shaped structure in the bulge of the Milky Way

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NASA Mars Rover Can Choose Laser Targets on Its Own

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NASA's Curiosity Mars rover autonomously selects some targets for the laser and telescopic camera of its ChemCam instrument. For example, on-board software analyzed the Navcam image at left, chose the target indicated with a yellow dot, and pointed ChemCam for laser shots and the image at right.

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Ultra-flat circuits will have unique properties: Rice University lab studies 2-D hybrids to see how they differ from common electronics

The Rice lab of theoretical physicist Boris Yakobson analyzed hybrids that put 2-D materials like graphene and boron nitride side by side to see what happens at the border. They found that the electronic characteristics of such "co-planar" hybrids differ from bulkier components.

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Hybrids of two-dimensional materials like the graphene-molybdenum disulfide illustrated here have electronic properties that don't follow the same rules as their 3-D cousins, according to Rice University researchers. The limited direct contact between the two materials creates an electric field that greatly increases the size of the p/n junction.

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Designing climate-friendly concrete, from the nanoscale up: New understanding of concrete’s properties could increase lifetime of the building material, decrease emissions

An MIT-led team has defined the nanoscale forces that control how particles pack together during the formation of cement “paste,” the material that holds together concrete and causes that ubiquitous construction material to be a major source of greenhouse gas emissions. By controlling those forces, the researchers will now be able to modify the microstructure of the hardened cement paste, reducing pores and other sources of weakness to make concrete stronger, stiffer, more fracture-resistant, and longer-lasting. Results from the researchers’ simulations explain experimental measurements that have confused observers for decades, and they may guide the way to other improvements, such as adding polymers to fill the pores and recycling waste concrete into a binder material, reducing the need to make new cement.

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The left and center diagrams show the structure of cement hydrate as determined by the researchers’ model, which calculates the positions of particles based on particle-to-particle forces. Each simulation box is about 600 nanometers wide. The packing fraction (the fraction of the box occupied by particles) is assumed to be 0.35 in the left diagram and 0.52 in the center one. Open pores, indicated by the white areas, are more prevalent at the lower packing fraction. The right-hand diagram is a sketch of cement hydrate published by T.C. Powers in 1958.

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A 'smart dress' for oil-degrading bacteria

Bionanotechnology research is targeted on functional structures synergistically combining macromolecules, cells, or multicellular assemblies with a wide range of nanomaterials. Providing micrometer-sized cells with tiny nanodevices expands the uses of the cultured microorganisms and requires nanoassembly on individual live cells.

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(a,b) Targeted movement of magnetic cells was facilitated by external magnetic field (in liquid media); (c) sedimentation of magnetically concentrated cells; (d) targeted movement and growth of magnetic cells on solid surface (inset shows a higher-magnification view of cells arranged on the surface).

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New remote-controlled microrobots for medical operations

For the past few years, scientists around the world have been studying ways to use miniature robots to better treat a variety of diseases. The robots are designed to enter the human body, where they can deliver drugs at specific locations or perform precise operations like clearing clogged-up arteries. By replacing invasive, often complicated surgery, they could optimize medicine.

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Scientists at EPFL and ETHZ have developed a new method for building microrobots that could be used in the body to deliver drugs and perform other medical operations.

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NASA's Hubble Looks to the Final Frontier

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NASA's Hubble Telescope Makes First Atmospheric Study of Earth-Sized Exoplanets

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Physicists collide ultracold atoms to observe key quantum principle

Physicists from New Zealand's University of Otago have used steerable 'optical tweezers' to split minute clouds of ultracold atoms and slowly smash them together to directly observe a key theoretical principle of quantum mechanics.

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University of Otago physicist Niels Kjærgaard and his team have used extremely precisely controlled laser beams to confine, accelerate and gently collide ultracold atomic clouds of fermionic potassium.
This allowed them to directly observe a key principle of quantum theory, the Pauli Exclusion Principle.
This principle predicts a forbidden zone along a meridian of the spherical halo of scattered particles, which the Otago experiments indeed unveiled.
The dark band in the graphic shows a rule derived from the principle in action. This rule is that indistinguishable fermions cannot scatter out at 90 degrees to the collision axis.

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