Phys.org October 28, 2020 While surface charge state of co-catalysts plays a critical role for boosting photocatalysis, the study on surface charge regulation via their precise structure control, remains rare. Researchers in China have fabricated an MOF-stabilized bimetallic Pd-Pt nanoparticles which feature adjustable Pt coordination environment and the controlled structure from core-shell to single-atom alloy (SAA). They found that Pt surface charge regulation can be alternatively achieved by changing its coordination environment and the structure of Pd-Pt co-catalyst, where the charge between Pd and Pt is redistributed. The optimized Pd-Pt composite exhibits an exceptionally high photocatalytic hydrogen production activity, far […]
Tag Archives: S&T China
A flexible color-changing film inspired by chameleon skin (w/video)
Nanowerk October 21, 2020 By tensing or relaxing their skin, chameleons can change the way light reflects from guanine crystals under the surface, producing structural coloration. The structural colors are different from the pigments that give many other creatures their hues. Currently available materials for mimicking chameleon skin is difficult to produce. Researchers in China introduced a flexible network structure in cellulose nanocrystals (CNCs), exerting a bridge effect for the rigid nanomaterials. These films display high flexibility with a fracture strain of up to 39%. Notably, stretching-induced structural color changes visible to the naked eye are realized, for the first […]
Moth-eye nanostructures make good anti-icing coatings
Physics World September 3, 2020 Researchers in Vietnam fabricated moth eye structure on the quartz substrate covered with a flat paraffin layer to isolate it in a cold and humid environment. The paraffin layer only stayed on the top of the nanostructure, separated it from the outside environment to obstruct heat energy being transferred to the cold substrate, and prevented the wetting transition, which was observed regularly on the rough surface. Numerous air blocks trapped inside the nanostructure also contributed to delayed heat transfer, leading to an increase in the freezing time of the attached water droplet. The nanostructure coated […]
An unusual superconductor
Phys.org September 3, 2020 Researchers in China investigated the superconducting properties of two-dimensional crystalline superconducting PdTe2 films grown by molecular beam epitaxy. They observed the experimental evidence of anomalous metallic state and detected type-II Ising superconductivity existing in centrosymmetric systems. Moreover, the superconductivity of PdTe2 films remains almost the same for more than 20 months without any protection layer. This macro-size ambient-stable superconducting system with strong spin-orbit coupling shows great potentials in superconducting electronic and spintronic applications…read more.
New fabric could help keep you cool in the summer, even without A/C
Science Daily July 29, 2020 When interspersed in fabric the thermally conductive boron nitride has the ability to transfer heat, allow moisture to evaporate from the skin and repel water. To improve the process researchers in China enabled boron nitride to better interpenetrate and remain porous. According to the researchers the material has improved thermal conductivity, moisture permeability, and better resistance to water penetrability and repellency…read more. TECHNICAL ARTICLE
Scientists develop novel transparent broadband electromagnetic interference shielding materials
Phys.org July 27, 2020 Electromagnetic interference shielding materials are visibly opaque. Researchers in China proposed and fabricated visibly transparent EMI shielding materials using an ultrathin silver layer sandwiched by oxides (SLSO) as building blocks. The structure exhibited the highest EMI shielding effectiveness (SE) of 70 dB at 27.6 GHz (>62 dB on average at 4–40 GHz) and a transmittance close to 90% at a visible wavelength of 550 nm, which is comparable with those of polyethylene terephthalate (PET) and glass substrates. The D-SLSO structure suppresses optical reflections as antireflection coatings and enhances EMI shielding via Fabry–Pérot interference. They describe other […]
Fossil fuel-free jet propulsion with air plasmas
Science Daily May 5, 2020 Researchers in China propose a prototype design of a propulsion thruster that utilizes air plasma induced by microwave ionization. They used a microwave air plasma jet thruster using high-temperature and high-pressure plasma generated by a 2.45 GHz microwave ionization chamber for injected pressurized air. They measured the lifting force and jet pressure at various settings of microwave power and the air flow rate and demonstrated that, given the same power consumption, its propulsion pressure is comparable to that of conventional airplane jet engines using fossil fuels. A carbon-emission free thruster could potentially be used as […]
New textile could keep you cool in the heat, warm in the cold
Phys.org April 1, 2020 Researchers in China freeze-spun silk and chitosan, a material from the hard outer skeleton of shellfish, into colored fibers with porous microstructures. They filled the pores with polyethylene glycol (PEG), a phase-changing polymer that absorbs and releases thermal energy. The threads were coated with polydimethylsiloxane to keep the liquid PEG from leaking out. The resulting fibers were strong, flexible, and water-repellent. To test the fibers, the researchers wove them into a patch of fabric and put inside a polyester glove. When a person wearing the glove placed their hand in a hot chamber (122°F), the solid […]
Graphene-based actuator swarm enables programmable deformation
Nanowerk April 1, 2020 Graphene-based actuators featuring fast and reversible deformation under various external stimuli are promising for soft robotics. However, these bimorph actuators are incapable of complex and programmable 3D deformation, which limits their practical application. Researchers in China fabricated a moisture-responsive graphene actuator swarm that has programmable shape-changing capability by programming the SU-8 patterns underneath with specific geometries and orientations on a continuous graphene oxide film, forming a swarm of bimorph actuators. They achieved predictable and complex deformations including bending, twisting, coiling, asymmetric bending, 3D folding and the combination of them due to the collective coupling and coordination […]
New Antenna Will Boost UAV Communication with Satellites
IEEE Spectrum March 10, 2020 Conventional sabre-like antennas generate a donut-shape radiation pattern, which provides an omnidirectional coverage and is ideal for air-to-ground communication. However, a donut-shape pattern has a null at its zenith which inhibits communication with other satellites. To provide signal directly above the antenna researchers in China designed a novel sabre-like antenna incorporated two metal radiators into the design. The first is a monopole, which is perpendicular to the ground with an omnidirectional pattern. The second is a dipole, which is parallel to the ground with broadside pattern – creating a signal that fills the blind spot […]