Science Daily December 20, 2019 A team of researchers in the US (University of Chicago, University of Pennsylvania) has shown that aging encodes a memory of the stresses imposed during preparation. Because of inhomogeneous local stresses, the material itself decides how to evolve by modifying stressed regions differently from those under less stress. Because material evolution occurs in response to stresses, aging can be “directed” to produce sought-after responses and unusual functionalities that do not inherently exist. Aging obeys a natural “greedy algorithm” as, at each instant, the material simply follows the path of most rapid and accessible relaxation. Their […]
Tag Archives: Materials science
Electronic map reveals ‘rules of the road’ in superconductor
Science Daily December 6, 2019 An international team of researchers (USA – Rice University, UC Berkeley, SLAC National Accelerator Laboratory, Lawrence Berkeley National Laboratory, Stanford University, China) has developed a band structure map from the data gathered from measurements of a single crystal of iron selenide as it was cooled to the point of superconductivity. They are making observations of different types of exotic materials and figuring out the quantum mechanical rules that govern electron behavior in those materials. The electronic structure helps deciding if a material will be a good conductor or a good insulator or a superconductor…read more. […]
New method to remove dust on solar panels
Science Daily December 9, 2019 To better understand the forces that attach and detach particles from surfaces during the self-cleaning mechanism and the effect of nanotextures on these forces, researchers in Israel prepared four silicon-based samples relevant to solar panels: (1) smooth hydrophilic (2) nanotextured hydrophilic surfaces and (3) smooth hydrophobic (4) nanotextured hydrophobic surfaces. They found that hydrophilic particle removal increased from ∼41%, from hydrophilic smooth Si wafers to 98% from superhydrophobic Si-based nanotextured surfaces. They determined that the reason for the increased particle removal is due to the reduction of the adhesion force between the particle and the […]
Novel material switches between electrically conducting and insulating states
Nanowerk December 4, 2019 Researchers at Northwestern University designed the picoscale crystalline structure of molybdenum oxynitride (MoON), to host the phase transition. The researchers found the metal-insulator transition (MIT) occurred near 600 degrees Celsius, revealing its potential for applications in high-temperature sensors and power electronics. They noted multiple design parameters influenced MoON’s phase transition. The inclusion of multiple anions in the material activated the phase transition due to specific electron configurations related to the spatial orientation of electronic orbitals. The findings offer insight into how subtle changes on the nanoscale can be used to control macroscopic behavior, like conductivity, in […]
Study sheds light on the peculiar ‘normal’ phase of high-temperature superconductors
Science Daily December 3, 2019 In the cuprate high-temperature superconductors, the metallic state above the highest transition temperature is anomalous and is known as the “strange metal.” An international team of researchers (USA – Stanford University, SLAC National Accelerator Laboratory, UC Berkeley, the Netherlands, Japan) studied this state using angle-resolved photoemission spectroscopy. With increasing doping across a temperature-independent critical value pc ~ 0.19, they observed that near the Brillouin zone boundary, the strange metal, characterized by an incoherent spectral function, abruptly reconstructs into a more conventional metal with quasiparticles. Above the temperature of superconducting fluctuations, the pseudo gap also discontinuously […]
Metal-organic framework captures and converts toxic air pollutant into industrial chemical
Nanowerk November 23, 2019 An international team of researchers (UK, USA – Oak Ridge National Laboratory, Lawrence Berkeley National Laboratory) has developed an MOF, denoted as MFM-520, that can capture atmospheric nitrogen dioxide at ambient pressures and temperatures—even at low concentrations and during flow—in the presence of moisture, sulfur dioxide and carbon dioxide. Despite the highly reactive nature of the pollutant, MFM-520 proved capable of being fully regenerated multiple times by degassing or by treatment with water from the air—a process that also converts nitrogen dioxide into nitric acid. The highest rate of NO2 uptake by this material occurs at […]
Clean carbon nanotubes with superb properties
Eurekalert November 19, 2019 An international team of researchers (Finland, USA – Rice University, Japan) has developed a new method to fabricate single-wall carbon nanotubes (SWCNT). They used aerosols of metal catalysts and gasses containing carbon which allows the researchers to carefully control the nanotube structure directly. The devices do not contain degrading processing chemicals on their surface. The method makes it possible to fabricate hundreds of individual carbon nanotube devices within 3 hours as opposed to the current method. They have shown that the aerosol-based nanotubes are superb in terms of their electronic quality. These clean devices help to […]
Foam offers way to manipulate light
EurekAlert November 18, 2019 Numerous examples of photonic band gaps have been shown previously in various types of crystals. With computational simulations researchers at Princeton University have shown that a Weaire-Phelan foam would allow some frequencies of light to pass through while completely reflecting others making it a photonic band gap material. The photonic band gap has a maximal size of 16.9% (at a volume fraction of 21.6% for a dielectric contrast ε=13) and a high degree of isotropy. With further development, the foam could transport and manipulate light used in telecommunications. Photonic band gap materials could guide the light […]
Synthetic biologists developing a new class of high-performance materials
Science Daily November 18, 2019 A team of researchers in the US (Northwestern University, University of Illinois, Stanford University, UT Austin, industry) developed a set of design rules to guide how ribosomes, a cell structure that makes protein, can incorporate new kinds of monomers, which can be bonded with identical molecules to form polymers. The rules guide how ribosomes, a cell structure that makes protein, can incorporate new kinds of monomers, which can be bonded with identical molecules to form polymers. These findings are an exciting step forward to achieving sequence-defined synthetic polymers. The ability to harness and adapt cellular […]
An electronic signal expands the material by a factor of 100
EurekAlert October 29, 2019 Materials, such as solids and gels, that change volume depending on temperature or pH have long been available. An international team of researchers (Sweden, UK) placed a conducting polymer with a thickness of a few micrometres around an electrically conducting carbon fibre. When electrical pulses with magnitudes of +0.5 V or +0.8 V are applied, the material changes its internal structure, then absorbs water and is finally converted to a gel that expands to 14 or 120 times the original volume. When pulses of magnitude +/- 0.5 V are repeatedly applied, the material expands by approximately […]