Nanowerk April 23, 2024 Almost all the experimentally created electron vortex beam (EVBs) manifest isotropic doughnut intensity patterns. Based on the correlation between local divergence angle of electron beam and phase gradient along azimuthal direction, researchers in China showed that free electrons could be tailored to EVBs with customizable intensity patterns independent of the carried OAM. As proof-of-concept, by using computer generated hologram and designing phase masks to shape the incident free electrons they tailored three structured EVBs carrying identical OAM to exhibit completely different intensity patterns. Through the modal decomposition, they quantitatively investigated their OAM spectral distributions and revealed […]
Tag Archives: S&T China
Long-term satellite observations show climatological characteristics of isolated deep convection over the Tibetan Plateau
EurekAlert April 10, 2024 Researchers in China investigated isolated deep convections (IDCs), which have a smaller spatial and temporal size than mesoscale convective systems (MCSs), over the TP in the rainy season during 2001–2020. They showed that IDCs mainly concentrated over the southern Tibetan plateau (TP). The larger IDC had intense precipitation contributing 20 %–30 % to total precipitation, with a larger percentage in July and August than in June and September. IDCs contribute more to both total precipitation and extreme precipitation over the TP compared to the surrounding plain regions. IDCs over the TP account for a larger fraction […]
Old crystal, new story for enhancing deep ultraviolet laser performance
Phys.org April 1, 2024 Researchers in China obtained 60-mW solid-state deep ultraviolet (DUV) laser at 193 nm with narrow linewidth with two stages of sum frequency generation in lithium triborate (LBO) crystals. The pump lasers were derived from a homemade Yb-hybrid laser. The Yb-hybrid laser was power scaling by a 2mm×2mm×30mm Yb:YAG bulk crystal. The 220-mW DUV laser at 221 nm, and the 193-nm laser delivered an average power of 60 mW with a pulse duration of 4.6 ns. The conversion efficiency reached 27% for 221 to 193 nm and 3% for 258 to 193 nm. According to the researchers […]
The spontaneous emergence of 1D superconducting stripes at a 2D interface in an oxide heterostructure
Phys.org April 8, 2024 Magnetism can cause a modulation of superconducting pairing in real space in both copper-based and iron-based materials. Researchers in China reported on the discovery of a spatially varying superconducting state residing at the interface between KTaO3 and ferromagnetic EuO. Electrical transport measurements revealed different values of the critical temperature and magnetic field at which the superconductivity breaks down when current was applied along the two orthogonal in-plane directions. This anisotropy occurred in low-carrier-density samples that were characterized by strong coupling between the Ta 5d and Eu 4f electrons, whereas in high-carrier-density samples, the coupling was weakened, […]
Waterproof ‘e-glove’ could help scuba divers communicate
Nanowerk April 10, 2024 Existing tactile sensing gloves fall short in terms of user comfort and are ill-suited for underwater applications. Researchers in China proposed and constructed a flexible hand gesture recognition glove (GRG) that contained high-performance micropillar tactile sensors (MPTSs) inspired by the flexible tube foot of a starfish. The sensor has a wide working range, superfast response time, reliable repeatability, and a low limit of detection and they were waterproof. When integrated with machine learning algorithm, the GRG system achieved intelligent recognition of 16 hand gestures under water, extending real-time and effective communication capabilities for divers. According to […]
Research team realizes magnonic frequency comb
Phys.org April 1, 2024 A direct analog of frequency combs in the magnonic systems has not been demonstrated to date. Researchers in China generated a new magnonic frequency comb in the resonator with giant mechanical oscillations through the magnomechanical interaction. It contained up to 20 comb lines, which were separated by the mechanical frequency of 10.08 MHz. The thermal effect based on the strong pump power induced the cyclic oscillation of the magnon frequency shift, which led to a periodic oscillation of the magnonic frequency comb. They demonstrated the stabilization and control of the frequency spacing of the magnonic frequency […]
A simple way to harvest more ‘blue energy’ from waves
Science Daily April 3, 2024 Due to the advantages of simple structure and flexibility for energy harvesting, the tube liquid–solid triboelectric nanogenerator (TLS-TENG) has attracted much attention. However, it is limited by low output power due to its low surface charge density and transfer efficiency. Researchers in China proposed and constructed TLS-TENG (SVE-TLS-TENG) with enhanced output performance. Through the space volume effect, the open-circuit voltage (Uoc), short-circuit current (Isc), and transfer charge (Qtc) of SVE-TLS-TENG they improved energy harvesting by 3.5 times, 2.3 times, and 2 times, respectively. The SVE-TLS-TENG has high output performance for harvesting low-frequency and high-entropy motion […]
A single photon emitter deterministically coupled to a topological corner state
Phys.org April 2, 2024 Researchers in China presented a single photon emitter that utilizes a single semiconductor quantum dot, deterministically coupled to a second-order topological corner state in a photonic crystal cavity. By investigating the Purcell enhancement of both single photon count and emission rate within this topological cavity, they got an experimental Purcell factor of Fp = 3.7. They demonstrated the on-demand emission of polarized single photons, with a second-order autocorrelation function g(2)(0) as low as 0.024 ± 0.103. According to the researchers their work may be used for customizing light-matter interactions in topologically nontrivial environments… read more. Open Access TECHNICAL ARTICLE
Researchers achieve >99% photoluminescence quantum yield in metal nanoclusters
Phys.org March 18, 2024 Metal nanoclusters have emerged as NIR–emissive materials, but their room-temperature photoluminescence quantum yield (PLQY), especially in solution, is often low. Researchers in China studied the photophysics of Au22(tBuPhC≡C)18 (Au22) and its alloy counterpart Au16Cu6(tBuPhC≡C)18 (Au16Cu6) (where tBu is tert-butyl and Ph is phenyl) and found that copper doping suppressed the nonradiative decay and promoted intersystem crossing rate ~300-fold higher. According to the researchers their approach could enable the development of highly emissive metal cluster materials… read more. TECHNICAL ARTICLE
China promises more money for science in 2024
Nature March 8, 2024 At its annual meeting this week, China’s legislative body, the National People’s Congress, promised to increase government funding for science by 10% in 2024. It’s the largest boost to funding in five years. The increase comes as the Chinese economy struggles to meet growth targets and is locked in a race for technological supremacy with the United States. “To win this game, China has to invest in science and technology, especially in basic research,” says Marina Zhang, who studies innovation with a focus on China… read more.