Science Alert April 12, 2019 There are around 20 different molecular varieties of water– some so esoteric and rare, they may only exist inside computer simulations, or buried within distant planets. The physical confinement of water at the nanoscale can play a major role in controlling its properties. Confinement in the nanometre range can inhibit the arrangement of water molecules into an ice structure, and thereby prevent crystallisation at subzero temperature and create a state of amorphous water. Researchers in Switzerland synthesised a new class of fat molecules that form into a soft biological material called a lipidic mesophase, an […]
Category Archives: Materials science
Observing a molecule stretch and bend in real-time
Phys.org April 9, 2019 In 2016 an international team of researchers (Spain, Poland, USA – Kansas State University, Germany) achieved the required spatial and temporal resolution to take snapshots of molecular dynamics without missing any events. Now the group has observed the structural bending and stretching of the triatomic molecular compound carbon disulphide, CS2. They reported that the ultrafast modifications in the molecular structure are driven by changes in the electronic structure of the molecule. This effect is key for important triatomic molecules such as CS2, since it can determine specific chemical reactions in the Earth’s atmosphere that could, for […]
A New ‘State’ of Matter Can Be Solid And Liquid at The Same Time
Science Alert April 9, 2019 Applying high pressures and temperatures to potassium creates a state in which most of the element’s atoms form a solid lattice structure. Researches in the UK used powerful computer simulations to observe this behaviour of around 20,000 potassium atoms under extreme conditions. When the pressure and temperature are high enough – around 2 to 4 Gigapascals – the potassium atoms arranged themselves in interlinked chains and lattices. The chemical interactions between the lattice atoms are strong, so they remain an ordered solid when a temperature between 400 and 800 Kelvin is applied. But meanwhile, the […]
The taming of the light screw
Phys.org March 22, 2019 Researchers in Germany performed high-harmonic generation measurements from silicon and quartz to demonstrate that the polarization states of the harmonics are not only determined by crystal symmetries, but can be dynamically controlled, as a consequence of the intertwined interband and intraband electronic dynamics. Using symmetry-dynamics duality they generated coherent circularly polarized harmonics from elliptically polarized pulses. The method is versatile and expected to find important applications in future studies of novel quantum materials such as strongly correlated materials, topological insulators, and magnetic materials… read more. Open Access TECHNICAL ARTICLE
Magnetic graphene switches between insulator and conductor
Phys.org February 1, 2019 By squashig layers of FePS3 together under high pressure (about 10 Gigapascals) an international team of researchers (UK, South Korea, France, Russia) found that it switched between an insulator and conductor. The conductivity could also be tuned by changing the pressure. These materials are characterised by weak mechanical forces between the planes of their crystal structure. Under pressure, the planes are pressed together, gradually and controllable pushing the system from three to two dimensions, and from insulator to metal. Even in two dimensions, the material retained its magnetism. The research opens possibility for producing two-dimensional materials with […]
Waterproof graphene electronic circuits
Science Daily January 30, 2019 Water molecules change the electrical resistance of this carbon material, which introduces a false signal into the sensor. An international team of researchers (Sweden, Germany) discovered that when this two-dimensional material is integrated with the metal of a circuit, contact resistance is not impaired by humidity. They used graphene together with gold metallization and silica substrates in transmission line model test structures, as well as computer simulations to demonstrate their discovery. As part of the European CO2-DETECT project, they are applying this new approach to create the first prototypes of graphene-based sensors to measure carbon […]
Turning Round Drops Square
American Physical Society Synopsis December 13, 2018 An international team of researchers (Canada, France) found that for a drop sandwiched between two thin, stretchable films can develop a noncircular outline, such as a square, with its exact shape depending on the amount of tension in the two films. They found that the partial wetting of droplets capped by taut elastic films is highly tunable. Adjusting the tension allows the contact angle and droplet morphology to be controlled. By exploiting these elastic boundaries, droplets can be made elliptical, with an adjustable aspect ratio, and can even be transformed into a nearly […]
Study reveals mechanisms that promote icing responsible for power disruptions
Eurekalert November 26, 2018 Researchers in China monitored the icing process (at 10 meters and 1.5 meters) of agglomerate fog, an event where massive amounts of fog come together during a cold surge which lasted for 102 hours. They found that agglomerate fogs, snow and rain, contributed to the icing process. They observed significant differences in the thickness and density of the accumulated ice, as well as the mechanism that contributed to icing growth and the duration of the icing at the two different heights. The sticking efficiency of snow particles has a significant impact on icing growth rate…read more. […]
Uncovering secret structure to explosives
Lawrence Livermore National Laboratory October 17, 2018 In most high explosives, detonation is initiated through a process where pores get compressed by a shockwave. Researchers at the Lawrence Livermore National Laboratory found that in an explosive compound called HMX when pores are at the surface, they speed up the reaction, if a shockwave hits a number of surface pores at once, they bootstrap each other. While they showed that many small pores can work together to accelerate one another’s burning, they also were able to identify a threshold where pores become so small that the reaction is extinguished. This examination […]
Metal that withstands ultra-high temperature and pressure identified
Science Daily September 27, 2018 Researchers in Japan analyzed the ultrahigh-temperature tensile creep behaviour of a TiC-reinforced Mo-Si-B-based alloy in the range of 1400–1600 °C at constant true stress range in vacuum. It displayed excellent creep strength with relatively reasonable creep parameters and moderate strain-rate oscillations. The findings have applications in aircraft jet engines and gas turbines for electric power generation…read more. Open Access TECHNICAL ARTICLE