Sentences with phrase «grain boundaries in»

Grain boundaries in p - n junction diodes fabricated in laser - recrystallized silicon thin films

A team of researchers found that randomly selected, high - angle, general grain boundaries in a nickel - bismuth (Ni - Bi) polycrystalline alloy can undergo interfacial reconstruction to form ordered superstructures, a discovery that enriches the theories and fundamental understandings of both grain boundary segregation and liquid metal embrittlement in physical metallurgy.

However, most grain boundaries in polycrystalline materials are so - called «general» grain boundaries of mixed tilt and twist character, which are not well understood due to the difficulties in characterizing and modeling them.

«Segregation - induced ordered superstructures at general grain boundaries in a Ni - Bi alloy: The discovery of ordered, segregation - induced superstructures at general grain boundaries challenges a traditional view in physical metallurgy.»

They created a micron - sized, individual graphene grain boundary in order to probe its electronic properties and study its role in gas sensing.

Not exact matches

«Be fearless in breaking new boundaries and don't be afraid to go against the grain of criticism along the way,» she said.

But researchers showed that it is enabled by faceting, as well as the formation of atomic - level steps at the grain boundaries, which allows separate interfacial reconstructions to occur at both terminating grain surface planes in a unique «bilayer» interfacial phase (wherein an «interfacial phase» refers to a thermodynamically 2 - D phase spontaneously - formed at an interface, which is also called a «complexion»).

This somewhat surprising discovery enriches our fundamental knowledge of the atomic - level segregation structures at general grain boundaries, which are important in controlling a broad range of mechanical and physical properties of polycrystalline alloys.

Specifically, it was unclear whether the segregated bismuth atoms can form reconstructed superstructures, the existence of which was not expected at the general grain boundaries, but have been revealed in this new study.

Prior studies of atomic - level grain boundary and segregation structures have been mostly focused on small - angle or special symmetrical tilt and twist boundaries with high symmetries and well - defined periodicities in artificial bicrystals.

The formation of such ordered superstructures and the associated interfacial reconstructions that change the 2 - D translational symmetries at both terminating grain planes, which had been thought impossible to be realized at general grain boundaries that should be lacking a long - range translational symmetry according to the classical theories in physical metallurgy, are enabled by faceting, as well as the formation of atomic - level steps at the grain boundaries.

When a large voltage is applied, the grain boundaries facilitate atomic motion, causing a change in resistance.

Bulk defects in a metal, such as grain boundaries, can create regions of increased strain at its surface that could affect its catalytic activity.

Grain boundaries create strained regions in polycrystalline materials by stabilizing dislocations and may provide a way to create high - energy surfaces for catalysis that are kinetically trapped.

The catalytic footprint of the grain boundary is commensurate with its dislocation - induced strain field, providing a strategy for broader exploitation of grain - boundary effects in heterogeneous catalysis.

The memristor characteristics come from the fact that the defects in the material are relatively mobile, especially in the presence of grain boundaries.»

In contrast, the new research suggests that once those isolated pores grow large enough to connect, the molten metal starts to flow, and most of it is able to percolate along grain boundaries.

Conventional metals dent, tear, and rust because of defects known as grain boundaries and dislocations, in which the crystals are pushed out of alignment and provide entry points for oxidation.

In fields like metallurgy, defects are removed «by turning up the temperature to give molecules more freedom to move grain boundaries and voids,» she said.

In many applications, grain boundaries are considered faults because they scatter electrons and may weaken the lattice.

«We can synthesize these grain boundaries on a micrometer scale in a controlled way,» Kumar said.

The boundary between the grains in these materials have always been assumed to be perpendicular to the surface.

But McCarthy found similar results even when she substantially altered the grain size in her samples, suggesting that grain boundaries are not the primary heat - generators in the process.

«The active component in a laser is a single crystal,» said Lograsso, who is also an Iowa State University adjunct professor of materials science and engineering, «because the crystal grain boundaries would scatter the light.»

The analysis also revealed single - atom defects and the width of disordered boundaries between grains, which was not previously possible in complex 3 - D boundaries.

They observed abrupt changes in magnetic properties at the grain boundaries.

«Understanding the three - dimensional structures of grain boundaries is a major challenge in materials science because they strongly influence the properties of materials,» Miao said.

«Fractures pay not the least attention to the cohesion minimums and not even to grain boundaries, where slip would take place so easily under stresses, but evidently occur quite suddenly in the form of an explosive fracture and not a slow expansion.

Its application to a model system of symmetric tilt boundaries in Cu uncovers an unexpected rich polymorphism in the grain boundary structures.

HP: Radiation damage in a mineral distorts and expands its lattice structure, just as well - organized, tightly - stacked blocks take up more space after someone suddenly shakes them.77 Ramdohr explained how a slow expansion over many years would produce fractures along only grain boundaries and planes of weakness, but a sudden, explosive expansion would produce the fractures he observed.

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He then made transistors in which charges could flow through molecules that were well aligned with each other, and others where the molecules were misaligned across the grain boundaries.

«The problem of understanding defects in organic electronic materials including grain boundaries is very important for any device application,» Rivnay said.

Salleo's group led a multidisciplinary team of researchers in making a systematic study of a likely culprit of the inconsistent transistor performance in polycrystalline devices: the «grain» boundaries between crystals.

To a dog, constant affection, gifts, and accommodations without rules, boundaries and limitations go against every grain in a dog's instinct.

Notable mandates: Successfully fended off a class action certification motion against Canadian National Railway over alleged overcharging for grain carriage; acted for Federated Co-operatives Ltd. in its $ 138 - million acquisition of oil company Triwest Exploration Inc.; Saskatchewan counsel to Wal - Mart Canada Realty Inc. and SmartCentres Realty Inc. on the $ 200 - million sale of shopping centres to Great - West Life Assurance Co. and London Life Insurance Co.; represented Northern Property REIT in $ 70 - million purchase of Nunavut properties; advised Saskatchewan Power Corp. on its $ 1.24 - billion Boundary Dam Integrated Carbon Capture and Storage Demonstration Project.