EurekAlert December 9, 2020 Researchers in Japan developed a strategy for identifying criminals from a single strand of hair, leveraging the fact that hair dyes are becoming increasingly common. Their approach involves finding out if two individual strands of hair belong to the same person based on the composition of hair dye products found on them. They used surface-enhanced Raman spectroscopy (SERS) and X-ray fluorescence (XRF) analysis. SERS can easily detect the overall differences in composition between different types of hair dyes, such as permanent, semi-permanent, or natural dyes. However, it is not enough to distinguish between hair coloring products […]
Tag Archives: Materials science
Mapping quantum structures with light to unlock their capabilities
Nanowerk December 4, 2020 All-optical band-structure reconstruction could directly connect electronic structure with the coveted quantum phenomena if strong light waves transported localized electrons within preselected bands. An international team of researchers (USA – University of Michigan, Germany) has shown that harmonic sideband (HSB) generation in monolayer tungsten diselenide creates distinct electronic interference combs in momentum space. Locating these momentum combs in spectroscopy enables super-resolution tomography of key band-structure details in situ. They experimentally tuned the optical-driver frequency by a full octave and showed that the predicted super-resolution manifests in a critical intensity and frequency dependence of HSBs. The concept […]
Oddly satisfying metamaterials store energy in their skin
Science Daily December 2, 2020 Metamaterials’ properties are controlled through structural design at the mesoscale, thus broadening the design space beyond the limits of traditional materials. An international team of researchers (USA – Purdue University, Switzerland) experimented with a family of mechanical metamaterials consisting of soft sheets and patterned array of reconfigurable bistable domes. The domes can be reversibly inverted at the local scale to generate programmable multistable shapes and tunable mechanical responses at the global scale. By 3D printing a robotic gripper with energy‐storing skin and a structure that can memorize and compute spatially‐distributed mechanical signals, they have shown […]
Physicists Observe Trippy ‘Vortex Rings’ in a Magnetic Material For The First Time
Science Alert December 1, 2020 Magnetic ring vortices were predicted over 20 years ago in 1998. An international team of researchers (UK, Switzerland, Ukraine, Russia) have found vortex rings inside a tiny pillar made of the magnetic material gadolinium-cobalt intermetallic compound GdCo2. They developed an X-ray nanotomography technique to image the three-dimensional magnetization structure inside a GdCo2 bulk magnet. The vortices were paired with their topological counterparts, antivortices. They also found closed magnetic loops present in vortex-antivortex pairs. After computationally analysing these structures in the context of magnetic vorticity they figured out these were doughnut-shaped ring vortices, intersected by magnetization […]
New technique seamlessly converts ammonia to green hydrogen
Phys.org November 18, 2020 A team of researchers in the US (Northwestern University, industry) built a unique electrochemical cell with a proton-conducting membrane and integrated it with an ammonia-splitting catalyst to convert ammonia to hydrogen. The ammonia encounters the catalyst that splits it into nitrogen and hydrogen which is immediately converted into protons; protons are electrically driven across the proton-conducting membrane in the electrochemical cell. Continually pulling off the hydrogen drives the reaction to go further than it would otherwise. By removing hydrogen the reaction is pushed forward, beyond what the ammonia-splitting catalyst can do alone. The technique is a […]
Pearls may provide new information processing options for biomedical, military innovations
Science Daily November 13, 2020 To overcome the hardware limitations of conventional spectrometers and hyperspectral imagers a team of researchers in the US (Purdue University, AFRL) has developed a spectral information processing scheme in which light transport through an Anderson-localized medium serves as an entropy source for compressive sampling directly in the frequency domain. As implied by the “lustrous” reflection originating from the exquisite multilayered nanostructures, a pearl (or mother-of-pearl) allows us to exploit the spatial and spectral intensity fluctuations originating from strong light localization for extracting salient spectral information with a compact and thin form factor. The research can […]
Power-free system harnesses evaporation to keep items cool
MIT News November 11, 2020 A camel’s coat, or a person’s clothing, can help to reduce loss of moisture while at the same time allowing enough sweat evaporation to provide a cooling effect. Tests have showed that a shaved camel loses 50 percent more moisture than an unshaved one, under identical conditions. Researchers at MIT have developed a system with a two-layer material with the bottom layer, substituting for sweat glands. It consists of hydrogel, a gelatin-like substance that consists mostly of water, contained in a sponge-like matrix from which the water can easily evaporate. This is covered with an […]
Now you see it, now you don’t: Hidden colours discovered by coincidence
Phys.org October 15, 2020 Unusual structural colors are demonstrated in thin‐film coatings due to a combination of optical interference and light scattering effects. These vivid colors are concealed under ambient illumination but can be observed when light is reflected from the film surface. An international team of researchers (Australia, China, Germany) explored the origin of the effect computationally and showed that, in thin‐films of lossless dielectrics coated on near‐perfect conductors, incident electromagnetic waves form standing waves. Electric field intensities at the thin film interfaces are maximized for wavelengths that fulfil destructive interference conditions, while nanoscale roughness can enhance scattering at […]
Room-temperature superconductor? Rochester lab sets new record toward long-sought goal
University of Rochester October 14, 2020 A team of researchers in the US (University of Rochester, industry, University of Nevada) reported superconductivity in a photochemically transformed carbonaceous sulfur hydride system, starting from elemental precursors, with a maximum superconducting transition temperature of 287.7 ± 1.2 kelvin (about 15 degrees Celsius) achieved at 267 ± 10 gigapascals. The superconducting state was observed over a broad pressure range in the diamond anvil cell. Superconductivity was established by the observation of zero resistance, a magnetic susceptibility of up to 190 gigapascals, and reduction of the transition temperature under an external magnetic field of up […]
New type of superconductor identified
Science Daily September 21, 2020 Strontium ruthenate (Sr2RuO4) has stood as the leading candidate for a spin-triplet superconductor for 26 years. Using resonant ultrasound spectroscopy an international team of researchers (USA – Cornell University, Florida State University, Germany, Japan) measured the entire symmetry-resolved elastic tensor Sr2RuO4 through the superconducting transition. They found a thermodynamic discontinuity in the shear elastic modulus which implies that the superconducting order parameter has two components, a two-component p-wave order parameter. As this order parameter appears to have been precluded by recent NMR experiments, they suggest that two other two-component order parameters are now the prime […]