Phys.org September 26, 2023 The highest frequency achievable for microwave signals is limited by the bandwidths of optoelectronic devices. To maximize the microwave frequency with a limited bandwidth of a photodetector (PD) and relieve the bandwidth bottleneck, researchers in China proposed to generate microwave signals with the single sideband (SSB) format by beating a continuous wave (CW) light with an optical SSB signal. By simply adjusting the frequency difference between the CW light and the carrier of the optical SSB signal, the frequency of the generated microwave SSB signal was changed correspondingly. In the experiment, amplitude shift keying (ASK) microwave […]
Successful optical biosensing using dual optical combs: High sensitivity and rapid detection of biomolecules
Phys.org September 26, 2023 Rapid, sensitive detection of biomolecules is important for biosensing of infectious pathogens as well as biomarkers and pollutants. Researchers in Japan have achieved rapid and sensitive detection of SARS-CoV-2 nucleocapsid protein antigen by enhancing the performance of optical biosensing based on optical frequency combs (OFC). The virus-concentration-dependent optical spectrum shift produced by antigen–antibody interactions was transformed into a photonic RF shift by a frequency conversion between the optical and RF regions in the OFC, facilitating rapid and sensitive detection with well-established electrical frequency measurements. The active-dummy temperature-drift compensation with a dual-comb configuration enabled the very small […]
Topological materials open a new pathway for exploring spin hall materials
Science Daily September 21, 2023 One of the hallmarks of Magnetic Weyl semimetals (mWSMs) is the emergence of large intrinsic anomalous Hall effect. On heating the mWSM above its Curie temperature, the magnetism vanishes while exchange-split Weyl point pairs collapse into doubly degenerate gapped Dirac states. Researchers in Japan found potential of these Dirac nodes in paramagnetic state for efficient spin current generation at room temperature via the spin Hall effect. They introduced Ni and In to separately substitute Co and Sn in a prototypal mWSMCo3Sn2S2 shandite film and tuned the Fermi level. Composition dependence of spin Hall conductivity for […]
Towards computational design of molecules with desired properties
Nanowerk September 25, 2023 The rational design of molecules with targeted quantum-mechanical (QM) properties requires an advanced understanding of the structure–property/property–property relationships (SPR/PPR) that exist across chemical compound space (CCS). An international team of researchers (Luxembourg, Austria, USA – Cornell University, Argonne National Laboratory) analyzed these fundamental relationships in the sector of CCS spanned by small (primarily organic) molecules using the recently developed dataset, a systematic, extensive, and tightly converged collection of 42 QM properties corresponding to ≈4.2M equilibrium and non-equilibrium molecular structures containing up to seven heavy/non-hydrogen atoms. By characterizing and enumerating progressively more complex manifolds of molecular property […]
Transistor-inspired ultra-sensitive materials heat up advanced data security
Nanowerk September 26, 2023 Researchers in China proposed a novel strategy for constructing highly sensitive TFMs with tunable emission (450–650 nm) toward multilevel information encryption which employs polarity-sensitive fluorophores with donor–acceptor–donor (D–A–D) type structures as emitters and long-chain alkanes as thermosensitive loading matrixes. The structure–function relationships between the performance of TFMs and the structures of both fluorescent emitters and phase-change molecules were systematically studied. The TFMs exhibited over 9500-fold fluorescence enhancement toward the temperature change, as well as ultrahigh relative temperature sensitivity up to 80% K−1, which were confirmed. The TFMs could be further developed as information-storage platforms within a […]
Transparent wood-based coating doesn’t fog up
Nanowerk September 26, 2023 Researchers in Finland developed a way to turn a waste material from wood into a bio-based transparent film that can be used for anti-fogging or anti-reflective coatings on glasses or vehicle windows. They prepared optically clear lignin nanoparticle dispersions from acetylated lignin. Thin lignin nanoparticle films remained transparent when deposited on glass and other smooth surfaces, and monolayered particle films provided effective antifogging properties. The particles could also be used to prepare multilayered films with bright structural colors that could be controlled via the film-thickness and were retained in dry conditions. They also developed an improved […]
Top 10 Science and Technology Inventions for the Week of September 22, 2023
01. AI models struggle to identify nonsense, says study 02. Battery-free robots use origami to change shape in mid-air 03. Exploring just how extreme future storms could get 04. Generating biskyrmions in a rare earth magnet 05. Scientists develop self-healing elastomer for flexible electronics 06. New method improves accuracy and resolution of lightning observations 07. Plumbing the depths of thermoelectrics in search of novel materials 08. Researchers develop high-performance zero thermal expansion composite for precision devices 09. Unveiling the invisible: A bioinspired CMOS-integrated polarization imaging sensor 10. Wifi can read through walls And others Accounting transparency effort tied to decreased […]
Accounting transparency effort tied to decreased funding for innovation
Phys.org September 18, 2023 According to an international team of researchers (US – University of North Carolina, UT Dallas, Germany, Norway, Brazil) enhanced financial statement disclosures of tax information under Financial Accounting Standards Board (FASB) Interpretation Number 48 (FIN 48) led to more IRS scrutiny and altered the incentives for corporate innovation. Using patent applications as a measure of corporate innovation, they used a difference-in-differences research design with publicly listed US firms as the treatment group and privately held US firms not subject to the disclosure requirements as the control group. They found evidence that following the onset of FIN […]
AI models struggle to identify nonsense, says study
Phys.org September 14, 2023 Neural network language models appear to be increasingly aligned with how humans process and generate language, but identifying their weaknesses through adversarial examples is challenging due to the discrete nature of language and the complexity of human language perception. An international team of researchers (USA – Columbia University, Israel) turned the models against each other by generating controversial sentence pairs where two language models disagreed about which sentence is more likely to occur. Considering nine language models (including n-gram, recurrent neural networks, and transformers), they created hundreds of controversial sentence pairs through synthetic optimization or by […]
Battery-free robots use origami to change shape in mid-air
Science Daily September 13, 2023 Researchers at the University of Washington designed origami battery-free microfliers using bistable leaf-out structures and found that a simple change in the shape of the origami structures caused two dramatically different falling behaviors. When unfolded and flat, the microfliers exhibited a tumbling behavior that increased lateral displacement in the wind. When folded inward, their orientation was stabilized, resulting in a downward descent that was less influenced by wind. To electronically transition between these two shapes, they designed a low-power electromagnetic actuator that produced peak forces of up to 200 millinewtons within 25 milliseconds while powered […]