01. Breaking an optical rule: Engineers find a way to manipulate light at the nanoscale 02. A little strain goes a long way in reducing fuel cell performance 03. Modified microwave oven cooks up next-gen semiconductors 04. Newly developed ice-shedding coating is 100 times stronger than others 05. A plastic film that can kill viruses using room lights 06. Producing hydrogen from seawater 07. Researchers help reveal a ‘blueprint’ for photosynthesis 08. Researchers suggest novel way to generate a light source made from entangled photons 09. Biomimetic dual-color domes programmable for encryption 10. Through the quantum looking glass And others… […]
Author Archives: Hema Viswanath
Anti-correlated plasma and THz pulse generation during two-color laser filamentation in air
Phys.org September 9, 2022 The THz generation efficiency and the plasma density generated by a filament in air have been found anti-correlated when pumped by two-color laser field. The plasma density near zero delay of two laser pulses has a minimum value, which is opposite to the trend of THz generation efficiency and contradicts common sense. The lower plasma density cannot be explained by the static tunneling model according to the conventional photocurrent model, but it might be attributed to the electron trapping by the excited states of nitrogen molecule. An international team of researchers (China, Japan) clarified the dominant […]
Billion-dollar US health agency gets new chief — but its direction remains in limbo
Nature September 13, 2022 President Joe Biden has selected Renee Wegrzyn, a biologist and former government scientist, as the inaugural director of the Advanced Research Projects Agency for Health (ARPA-H). Launched in March with a US$1-billion budget, ARPA-H aims to shake up the conventional model of funding biomedical research by funding high-risk, high-reward research in the life sciences. The Biden administration intends the agency to emulate the DARPA. Researchers applaud Biden’s choice, but say Wegrzyn will have her work cut out for her — there are many details about the agency that are still in limbo…read more.
Biomimetic dual-color domes programmable for encryption
Nanowerk September 15, 2022 Spots with dual structural colors on the skin of some organisms in nature are of interest due to the unique function of their dye-free colors. However, imitation of them requires complicated manufacturing processes, expensive equipment, and multiple predesigned building blocks. Researchers in Hong Kong have developed a one-pot strategy based on the phase-separation-assisted nonuniform self-assembly of monosized silica nanoparticles to construct domes with dual structural colors. In drying poly(ethylene glycol)-dextran-based (PEG-DEX) droplets, monosized nanoparticles distributed nonuniformly in two compartments due to the droplet inner flow and different nanoparticle compatibility with the two phases. The dome colors […]
Breaking an optical rule: Engineers find a way to manipulate light at the nanoscale
Phys.org September 12, 2022 According to Moss rule the absorption edge and the sub-bandgap refractive index of a semiconductor exhibit a rigid trade-off setting an upper limit on the refractive index of a dielectric for a given operating wavelength. According to a team of researchers in the US (Rice University, Johns Hopkins University) there are many dielectric materials that surpass the Moss rule, referred to as super-Mossian dielectrics. They discussed the general features of super-Mossian dielectrics and their physical origin to facilitate the search for high index dielectrics. They developed iron pyrite with index nearly 40% higher than the Moss […]
Filling a vital gap in climate models
Phys.org September 13, 2022 The persistent Southern Ocean (SO) shortwave radiation causes biases in climate models. An international team of researchers (Australia, USA – University of Oklahoma) investigated and characterized cloud and precipitation processes over the Southern Ocean from synoptic to micro scales using the observations collected during the Clouds Aerosols Precipitation Radiation and atmospheric Composition Over the Southern Ocean 2016 and 2018 field campaigns. The cloud and precipitation regimes corresponded to the seven thermodynamic clusters established using a K-means clustering technique, while less distinctions were evident using the cyclone and (cold) front compositing methods. Cloud radar and disdrometer data […]
A little strain goes a long way in reducing fuel cell performance
Science Daily September 9, 2022 Using a proton-conducting oxide as an electrolyte film in electrochemical devices introduces an interface, which thermally and chemically generates mechanical strain. To reduce the strain researchers in Japan focused on BZY20, which is a combination of yttrium, barium, zirconium, and oxygen atoms. They found that the atoms on the edges of this cube are 2% closer at the interface between the oxide and the surface than in layers far away from the surface. This compressive strain reduces the proton conductivity to nearly 1/100,000 of what it is in bulk samples. As the layers build up, […]
Modified microwave oven cooks up next-gen semiconductors
Nanowerk September 9, 2022 The doped semiconductor material must be sufficiently stable for the fabrication and operation of electronic devices. An international team of researchers (USA – Cornell University, industry, Taiwan, Spain) theorized that microwaves could be used to activate the excess dopants, but the previous microwave annealers produced “standing waves” that prevented consistent dopant activation. According to the researchers this discovery could be used to produce semiconductor materials and electronics appearing around the year 2025. It can potentially enable leading manufacturers to scale down to just 2 nanometers…read more. TECHNICAL ARTICLE
Newly developed ice-shedding coating is 100 times stronger than others
Phys.org September 12, 2022 Many of the current ice-shedding materials have low durability limiting their applicability. Researchers at the University of Houston used the concept of “fracture-controlled surface” to affect the interfacial crack nucleation and growth on the surfaces through coordinated mechanical and chemical heterogeneity in the material structure. Measurements indicated low ice adhesion, high mechanical durability, and three orders of magnitude greater than other state-of-the-art ice-shedding materials. They pre-specified the crack nucleation coordinates at the interface and guided the crack growth in an interfacial plane, with no kinking in other directions to maximize the energy that goes towards crack […]
A plastic film that can kill viruses using room lights
Phys.org September 9, 2022 Researchers in the UK have developed a thin, 30 μm, flexible, robust low-density polyethylene (LDPE) film loaded with 30 wt% P25 TiO2 and subsequently rendered highly active photocatalytically by exposing it to UVA (352 nm, 1.5 mW cm−2) for 144 h. The film was tested for anti-viral activity using two strains of influenza A virus, a highly stable picornavirus called EMCV and SARS-CoV-2, exposing it to either UVA radiation or with light from a cool white light fluorescent lamp. The film was effective at killing all the viruses—even in a room lit with just white fluorescent […]