Science

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Conformal transfer of graphene for reproducible device fabrication

Conformal transfer of graphene on a prepatterned substrate is a viable technology for reproducible fabrication of graphene devices. Such is the conclusion of a recent study by a team of scientists from Germany, the Netherlands, Spain and Saudi Arabia.

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Reliable wafer scale production of graphene devices.

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Perseid meteors to light up summer skies

The evening of Wednesday 12 August into the morning of Thursday 13 August sees the annual maximum of the Perseid meteor shower. This year, a new moon makes prospects for watching this natural firework display particularly good.

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Charge density and optical properties of multicomponent crystals

Optical materials serve a major role in modern sciences and technology. Many of the devices we use feature technology resulting from material discoveries in this fast moving area of research. Nowadays, the need for more efficient devices and minimisation in optoelectronics requires a novel approach towards crystal engineering of functional solids. A solution can be multicomponent materials built from either organic or mixed organic and inorganic components selected in a specific way, to combine molecular and structural properties to form a 3D architecture. Optical properties of a crystal strongly depend on two factors, i.e. the spatial distribution of molecules in the crystal structure and the electronic properties of molecular building blocks. The latter are easy to predict whereas the former are not. Crystal symmetry is often a key to obtaining a desired property. Noncentrosymmetric crystal structure (chiral/polar) is a necessary (limiting) condition for such properties as nonlinear properties of even order and linear properties like optical activity, piezoelectricity, pyroelectricity and ferroelectricity. However, fulfilling symmetry rules does not guarantee the existence of a physical effect. The choice of building blocks is crucial; in ideal cases, push-pull molecules should be linked with constituents enabling synthon formation flexibility.

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APIs in the design of multi-component functional solids are shown.

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Copper clusters capture and convert carbon dioxide to make fuel

Capture and convert--this is the motto of carbon dioxide reduction, a process that stops the greenhouse gas before it escapes from chimneys and power plants into the atmosphere and instead turns it into a useful product.

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A copper tetramer catalyst created by researchers at Argonne National Laboratory may help capture and convert carbon dioxide in a way that ultimately saves energy. It consists of small clusters of four copper atoms each, supported on a thin film of aluminum oxide. These catalysts work by binding to carbon dioxide molecules, orienting them in a way that is ideal for chemical reactions. The structure of the copper tetramer is such that most of its binding sites are open, which means it can attach more strongly to carbon dioxide and can better accelerate the conversion.

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Flexible dielectric polymer can stand the heat

Easily manufactured, low cost, lightweight, flexible dielectric polymers that can operate at high temperatures may be the solution to energy storage and power conversion in electric vehicles and other high temperature applications, according to a team of Penn State engineers.

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Researcher holds flexible dielectric material. Pull out shows boron nitride nanosheets.

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World's quietest gas lets physicists hear faint quantum effects

Physicists at the University of California, Berkeley, have cooled a gas to the quietest state ever achieved, hoping to detect faint quantum effects lost in the din of colder but noisier fluids.

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In most ultracold Bose-Einstein Condensates (BEC), the quantum gas (yellow peak) is accompanied by normal gas jiggling with thermal noise (the blue hump below the peak). As the noise or entropy is decreased, however, the jiggling disappears to leave an almost pure quantum gas. Ryan Olf graphic.

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Atomic view of microtubules: Berkeley Lab researchers achieve record 3.5 angstroms resolution and visualize action of a major microtubule-regulating protein

Microtubules, hollow fibers of tubulin protein only a few nanometers in diameter, form the cytoskeletons of living cells and play a crucial role in cell division (mitosis) through their ability to undergo rapid growth and shrinkage, a property called "dynamic instability." Through a combination of high-resolution cryo-electron microscopy (cryo-EM) and a unique methodology for image analysis, a team of researchers with Berkeley Lab and the University of California (UC) Berkeley has produced an atomic view of microtubules that enabled them to identify the crucial role played by a family of end-binding (EB) proteins in regulating microtubule dynamic instability.

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Microtubules are hollow cylinders with walls made up of tubulin proteins -- alpha (green) and beta (blue) -- plus EB proteins (orange) that can either stabilize or destabilize the structure of the tubulin proteins.

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Diagnosis of Salmonella Bacterium-Caused Food Poisoning by Biosensors

Iranian researchers produced a biosensor with high sensitivity and selectivity, in a laboratorial study, which can successfully detect a type of bacterium that causes salmonella poisoning in food samples.

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NASA's Spitzer Confirms Closest Rocky Exoplanet

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This artist's concept shows the silhouette of a rocky planet, dubbed HD 219134b. At 21 light-years away, the planet is the closest outside of our solar system that can be seen crossing, or transiting, its star.

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Solid state physics: Quantum matter stuck in unrest

Using ultracold atoms trapped in light crystals, scientists from the Ludwig-Maximilians-Universitaet (LMU) in Munich, the Max Planck Institute of Quantum Optics, and the Weizmann Institute observe a novel state of matter that never thermalizes.

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Schematic illustration of the experiment. An initial density modualtion is imprinted onto the ultracold atoms held in the optical lattice potential (1). Without any disorder, the density modulation is washed out completely in the ensuing dynamics, indicating relaxation towards a thermal equilibrium state (2). In the presence of sufficiently strong disorder, the researchers find that even for long evolution times the system retains memory of the initial state, indicating a non-thermal state in which the system remains stuck (3).