Nanowerk February 4, 2019 Researchers at UC Riverside constructed an ultrathin sandwich of the semiconductor molybdenum ditelluride between layers of graphene and bombarded the material with superfast laser pulses. They detected evidence of condensation into the equivalent of a liquid. As they turned up the amount of energy being dumped into the system, they saw the formation of an ‘anomalous photocurrent ring’ in the material. It grew like a droplet, rather than behaving like a gas. The research opens a pathway for development of practical and efficient devices to generate and detect light at terahertz wavelengths. Such devices could be […]
Author Archives: Hema Viswanath
Passing aircraft wring extra snow and rain out of clouds
Science Daily January 31, 2019 Researchers in the UK observed that existing precipitation is enhanced locally on spatial scales from a few kilometers to several tens of kilometers. The precipitation intensity in these localized areas was 6‐14 times higher than the background large‐scale precipitation rate. Surface observations and dual‐polarization radar data indicate that snowflakes within the ice portion of the falling precipitation in the intensification regions are larger and more isotropic than in the surrounding precipitation. There appears to be an increase in the ice particle number concentration within the intensification region. The observed events were linked to arriving or […]
New 3D printer shapes objects with rays of light
Science Daily January 31, 2019 A team of researchers in the US (UC Berkeley, Lawrence Livermore National Laboratory) has developed printer called “replicator” that relies on a resin composed of liquid polymers mixed with photosensitive molecules and dissolved oxygen. Light activates the photosensitive compound which depletes the oxygen. Only in those 3D regions where all the oxygen has been used up do the polymers form the “cross-links” that transform the resin from a liquid to a solid. Unused resin can be recycled by heating it in an oxygen atmosphere. A lot of the underlying theory behind the printer can be […]
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 […]
Laser capable of emitting light quiet enough to move demanding scientific applications
Science Daily February 1, 2019 Under a DARPA sponsored initiative an international team of researcher (USA – UC Santa Barbara, industry partners, Northern Arizona University, Yale University, Portugal) has developed a chip-scale laser capable of emitting light with a fundamental linewidth of less than 1 Hz. They leveraged stimulated Brillouin scattering to build the lasers. The circuits were built with waveguides that are extremely low loss. They formed into a Brillouin laser ring cavity on the chip. They can store an extremely large number of photons on the chip, handle extremely high levels of optical power inside the optical cavity […]
Invisible tags: Physicists write, read and erase using light
Nanowerk February 1, 2019 Researchers in Germany introduced organic luminescent molecules plastic foils. In the beginning, these molecules are in an inactive, dark state. By locally using ultraviolet irradiation, it is possible to turn the dark state into an active, luminescent one. By mask illumination or laser writing, activated patterns can be printed and the imprinted information can be read. Ultraviolet radiation induces a chemical reaction which efficiently removes the oxygen from the layer activating the luminescent molecules. By illuminating with infrared light, the tag is erased completely, and new data can be written into it. The deactivation process is […]
How machine learning could keep dangerous DNA out of terrorists’ hands
Nature News January 31, 2019 The US government is backing efforts that use machine learning to detect whether a DNA sequence encodes part of a dangerous pathogen. Researchers are beginning to make progress towards designing artificial-intelligence-based screening tools, and several groups are presenting early results at the American Society for Microbiology (ASM) Biothreats meeting in Arlington, Virginia, on 31 January. In 2016, IARPA launched an initiative to design better algorithms for spotting potentially threatening sequences. Information about the basic biology of organisms — such as a universal DNA sequence that allows toxins or viruses to stick to cells could help […]
Extreme rainfall events are connected around the world
Science Daily January 30, 2019 An international team of researchers (UK, Germany, Russia) developed a new method rooted in complex system theory to study high-resolution satellite data of rainfall. By breaking the globe into a grid, the team could see where events occurred and determine how ‘synchronous’ they were. The results from this ‘complex network’ model, analysed using their understanding of the motion of the atmosphere, revealed a possible mechanism for how the events were connected. The research could help better predict when and where extreme rainfall events will occur around the world. The insights can be used to test […]
Engineers create a robot that can ‘imagine’ itself
Science Daily January 30, 2019 Researchers at Columbia University have created a robot that learns what it is, from scratch, with zero prior knowledge of physics, geometry, or motor dynamics. After a brief period of “babbling,” and within about a day of intensive computing, the robot creates a self-simulation and uses that self-simulator internally to contemplate and adapt to different situations, handling new tasks as well as detecting and repairing damage in its own body. Using a four-degree-of-freedom articulated robotic arm, initially the robot moved randomly and collected approximately one thousand trajectories. Then used deep learning to create a self-model. […]
Computational algorithm to reduce electromagnetic noise in electronic circuits developed
Science Daily January 31, 2019 Researchers in Japan developed algorithm for computer simulation of electric circuits in which transmission lines are connected with lumped element models. They introduced the incidence matrix found in circuit theory and time domain impedance to connect partial differential equations and ordinary differential equations which are used to solve transmission line problems. Based on the results of calculations using this algorithm, the researchers demonstrated that EM noise could be reduced by using the symmetric 3-line configuration of the circuit. Their calculation method is for one-dimensional multi-conductor transmission lines, but they have already developed a calculation algorithm […]