Phys.org March 12, 2021 An international team of researchers (USA – Clemson University, Los Alamos National Laboratory, University of Alabama, China) observed the ultrafast dynamics of trapped carriers in organic methyl ammonium lead halide perovskite thin films by ultrafast photocurrent spectroscopy. Upon ultrafast laser excitation, trapped carriers followed a phonon assisted tunneling mechanism and a hopping transport mechanism along ultra-shallow to shallow trap states ranging from 1.72–11.51 millielectronvolts. They validated the transport mechanisms by highlighting trap state dynamics, including trapping rates, de-trapping rates and trap properties, such as trap density, trap levels, and capture-cross sections. The work establishes a foundation […]
Author Archives: Hema Viswanath
Scientists develop new approach to predict how liquids freeze
Phys.org March 18, 2021 Denser phases and the complexity of the freezing liquids into solids are a challenge for computational modelling. Researchers in the UK developed novel computational approaches to study wax which has multiple frozen arrangements. Using their method, they were able to predict its melting point within 2°C of the experimental value. Like waxes, oils such as diesel fuel can also freeze at many stages and exhibit different solid properties. Therefore, methods to predict the molecular and atomic intricacies of liquid transitions to different types of ‘solid’ oils could have several potential real-world applications, from helping better predict […]
Study predicts the oceans will start emitting ozone-depleting CFCs
MIT News March 15, 2021 The levels of CFC-11 in the atmosphere have been steadily declining since 2010 under the Montreal Protocol, ocean absorbing about 5 to 10 percent of all manufactured CFC-11 emissions. A team of researchers in the US (MIT, Colorado State University, UC Santa Barbara, NASA Goddard Space Flight Center) looked to pinpoint when the ocean would become a source of the chemical, and to what extent the ocean would contribute to CFC-11 concentrations in the atmosphere. Through a hierarchy of models to simulate the mixing within and between the ocean and atmosphere, and adding anthropogenic emissions […]
Team creates new ultralightweight, crush-resistant tensegrity metamaterials
Phys.org March 11, 2021 Catastrophic collapse of materials and structures is the inevitable consequence of a chain reaction of locally confined damage. A-team of researchers in the US (UC Irvine, Georgia Institute of Technology) created mechanical metamaterials that delocalize deformations to prevent failure. They used direct laser writing technique to generate elementary cells sized between 10 and 20 microns which were built up into eight-unit supercells that could be assembled with others to make a continuous structure. They showed that failure resistance is up to 25‐fold enhancement in deformability and orders of magnitude increased energy absorption capability without failure over […]
UC announces breakthrough open access deal with publishing giant Elsevier
UC Berkeley March 16, 2021 Two years after cutting ties with publishing industry giant Elsevier, producer of more than 2,600 scholarly journals, the University of California system announced that it has reached with Elsevier the largest open access agreement of its kind in North America. As of April 1, all research with a UC lead author published in Elsevier’s hybrid and open access journals will be open access by default, so that everyone in the world can read it for free. This fulfills the UC faculty’s goals for its so-called transformative open access agreements with publishers — universal open access […]
When memory qubits and photons get entangled
Phys.org March 15, 2021 The implementation of efficient interfaces between photons and stationary qubits is crucial for the rate of information transfer and the scalability of a quantum network. With their experimental setup researchers in Germany demonstrated quantum entanglement between a stationary qubit and a photon out of an optical fiber resonator. They showed the generation of deterministic entanglement at a high fidelity of 90.1(17)% between a trapped Yb ion and a photon emitted into the resonator mode. And achieved a success probability for generation and detection of entanglement for a single shot of 2.5 × 10−3 resulting in 62 Hz entanglement rate. […]
Top 10 Science and Technology Inventions for the Week of March 12, 2021
01. Researchers virtually open and read sealed historic letters 02. Army Trains AI to Identify Faces in the Dark 03. Innovative flat optics will usher the next technological revolution 04. New quantum theory heats up thermodynamic research 05. New research could boost a solar-powered fuel made by splitting water 06. Twistoptics: A new way to control optical nonlinearity 07. Scientists have synthesized a new high-temperature superconductor 08. Scientists propose novel self-modulation scheme in seeded free-electron lasers 09. Linear systems are the workhorse of modern computation 10. Reemergence of Human Monkeypox and Declining Population Immunity in the Context of Urbanization, Nigeria, […]
2021 BAA for Development of Medical Countermeasures for Biological Threats
Global Biodefense March 2, 2021 The National Institute of Allergy and Infectious Diseases (NIAID) solicitation contains multiple distinct Research Areas. The goal of Research Area 1 is to advance vaccine technologies and platforms which could be deployed against agents important for biodefense and/or emerging pathogens. Pathogens of particular interest include (but are not limited to): Burkholderia spp, Francisella tularensis, Yersinia pestis, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Candida auris. A second objective is to support development of vaccines for emerging viruses and pandemic preparedness. Targets of particular interest include: Vaccines that target coronaviruses with pandemic potential, Development of pan-coronavirus (pan-CoV) […]
Army Trains AI to Identify Faces in the Dark
IEEE Spectrum March 9, 2021 To develop a nighttime and low-light face recognition capability for the unconstrained or difficult lighting settings a team of researchers in the US (West Virginia University, Army Research Laboratory, Johns Hopkins University, University of Nebraska, industry) unveiled a dataset called Research Laboratory Visible-Thermal Face Dataset (ARLVTF) with over 500,000 images from 395 subjects. The data was captured using a LWIR camera mounted alongside a stereo setup of three visible spectrum cameras. Variability in expressions, pose, and eyewear were systematically recorded. The dataset has been curated with extensive annotations, metadata, and standardized protocols for evaluation. The […]
A device-independent protocol for more efficient random number generation
Phys.org March 9, 2021 With the growing availability of experimental loophole-free Bell tests it has become possible to implement a new class of device-independent random number generators whose output can be certified to be uniformly random without requiring a detailed model of the quantum devices used. However, all these experiments require many input bits to certify a small number of output bits, and it is an outstanding challenge to develop a system that generates more randomness than is consumes. An international team of researchers (USA -University of Colorado, NIST, University of Maryland, Spain, Japan) developed a device-independent spot-checking protocol that […]