Phys.org August 21, 2024 Existing optical switching solutions are inadequate for addressing flexible information exchange among the mode channels. Researchers in China introduced a flexible mode switching system in a multimode fibre based on an optical neural network chip. The system utilized the flexibility of on-chip optical neural networks along with an all-fibre orbital angular momentum (OAM) mode multiplexer-demultiplexer to achieve mode switching among the three OAM modes within a multimode fibre. They validated the system by successfully transmitting different modulation formats across various modes. According to the researchers their system could provide effective optical switching in practical multimode communication […]
Tag Archives: S&T China
Machine learning and better radar solve the ‘cloud cover’ problem
Phys.org August 6, 2024 The continuous retrieval of clear-sky land surface temperature (LST) is important for monitoring vegetation temperature and assessing water stress conditions. However, the extensive cloud cover poses challenges in accurately forecasting LST in regions characterized by diverse vegetation types and complex terrains. Researchers in China proposed a synthetic aperture radar – and digital elevation model (DEM)-integrated LST reconstruction model (SDX-LST) to assess the practicality and robustness of the SDX-LST model. To test the model, they selected areas in America spanning a wide range of longitude and latitude and having obvious differences in topography, landforms, and vegetation. According […]
Synergistic aerogel materials developed for heat and fire insulation
Phys.org August 2, 2024 Researchers in China demonstrated an interpenetrated multinetwork hybrid aerogel realizing thermal insulation, flame retardancy, and high compression modulus. One-dimensional hydroxyapatite nanowires (HAP) formed a three-dimensional interpenetrated multinetwork structure to optimize the thermal conductivity. The multinetwork hybrid aerogels exhibited thermal insulation performance in room temperature and enhanced ultrahigh compression modulus, flame retardancy and self-extinguishing smoke suppression properties. According to the researchers multinetwork hybrid aerogels are promising candidates for efficient heat insulation, fire prevention, and robust applications… read more. TECHNICAL ARTICLE
A novel thermal insulation material for ultra-high temperature applications: Hierarchical porous high-entropy ceramics
Phys.org July 22, 2024 To meet the emerging demands for thermal protection materials is a critical challenge. Researchers in China developed a novel porous high-entropy carbide (PHEC) ceramic fabricated by a self-foaming method using commercially available metal chloride and furfuryl alcohol as the precursor. The PHEC ceramic was constructed by microspheres with a size of 2 µm, high porosity and an interconnected frame. The microspheres consisted of high-entropy carbide grains resulting in abundant interface and nanosized pores in the PHEC ceramic. It has outstanding compressive strength and exceptionally low thermal conductivity at room temperature. According to the researchers their work […]
Inverse design method improves high-temperature performance of carbide coatings
Phys.org July 3, 2024 Researchers in China prepared the (Hf0.36Zr0.24Ti0.1Sc0.1Y0.1La0.1)C1-δ (HEC) coatings. The HEC possesses higher toughness with a higher Pugh’s ratio of 1.55 in comparison with HfC (1.30). The in-situ formed dense (Hf0.36Zr0.24Ti0.1Sc0.1Y0.1La0.1)O2-δ oxide scale during ablation benefits to improve the anti-ablation performance was attributed to its high structural adaptability with a lattice constant change not exceeding 0.19 % at 2000–2300 °C. According to the researchers the current investigation demonstrated the effectiveness of the inverse theoretical design, providing a novel optimization approach for ablation protection of high-entropy carbide coatings… read more. Open Access TECHNICAL ARTICLE
A high-temperature superconductor with zero resistance that exhibits strange metal behavior
Phys.org June 25, 2024 In recent experimental signatures of superconductivity close to 80 K in La3Ni2O7 under pressure, a zero-resistance was not observed. Researchers in China showed that the zero-resistance state does exist in single crystals of La3Ni2O7. They found that the system remained metallic under applied pressures, suggesting the absence of a metal–insulator transition proximate to the superconductivity. Analysis of the normal state T-linear resistance revealed a link between this strange-metal behaviour and superconductivity. This was in line with other classes of unconventional superconductors, including the cuprates and Fe-based superconductors. According to the researchers further investigations exploring the interplay of […]
Novel crystals enhance mid-infrared laser performance
Phys.org May 30, 2024 Researchers in China demonstrated a 978 nm laser diode (LD) side-pumped YSGG/Er:YSGG/YSGG composite crystal with a size of Ф 3 mm × 65 mm and continuous-wave (CW) mode. By optimizing resonator length and output mirror transmittance, a maximum output power of 28.02 W was generated, corresponding to slope efficiency of 17.55% and optical-optical efficiency of 12.29%, respectively. The thermal focal lengths were obtained by resonator stability condition. The laser wavelength was centered near 2.8 µm. Moreover, the beam quality factors 2/2 were fitted to be 8.14 and 7.35, respectively. The results indicated that a high-performance 2.8 µm CW laser could […]
Researchers create new type of composite material for shielding against neutron and gamma radiation
Phys.org May 24, 2024 Researchers in China created a new type of composite material for shielding against neutron and gamma radiation using micron plate Sm2O3 (samarium oxide) to reinforce boron-containing polyethylene with different specific surface areas and particle size distributions. The fillers were added to boron-containing polyethylene to create composites. The composites showed improved thermal stability, increased the melting temperature, mechanical strength, and radiation shielding properties compared to materials without the fillers. Tests revealed that the composite material could block 98.7% of neutron radiation from a 252Cf source and 72.1% of gamma radiation from a 137Cs source when the material […]
Scientists create black arsenic visible infrared photodetectors
Phys.org May 8, 2024 Black arsenic as 2-dimensional van der Waals layered material is a promising candidate for electronic and photonic applications because of tunable bandgap layers, high carrier mobility, and anisotropic transport feature. However, the potential of black arsenic for engineering nanophotoelectronic devices in the range from visible to near-infrared wavelength has not been reported. Researchers in China used black arsenic in visible–infrared detectors at the range from 520 to 1,550 nm, exhibiting a photoresponsivity of 0.4 A·W−1 and a detective of 1.37 × 108 Jones… read more. Open Access TECHNICAL ARTICLE
Stable magnetic bundles achieved at room temperature and zero magnetic field
Phys.org May 10, 2024 Through a combination of pulsed currents and reversed magnetic fields, researchers in China experimentally achieved skyrmion bundles with different integer Q values in the chiral magnet Co8Zn10Mn2. They demonstrated the field-driven annihilation of high-Q bundles and presented a phase diagram as a function of temperature and field. Their findings were corroborated by micromagnetic simulations… read more. Open Access TECHNICAL ARTICLE