Results 91 to 100 of about 1,489 (276)

Research on the NB-IoT Random Access in LEO Satellite IoT

open access: yes天地一体化信息网络, 2021
Narrowband internet of things (NB-IoT) technology is widely used in data communications for a large number of low-speed and low-power devices, but it is diff cult to provide services for remote areas that cannot be covered by terrestrial networks.With ...
Haodong LIU   +4 more
doaj  

Phase Diagrams and Piezoelectric Properties of Wurtzite Al1−x−yScxGdyN Heterostructural Alloys

open access: yesAdvanced Science, EarlyView.
This study demonstrates ferroelectricity and piezoelectric properties improvement of quaternary wurtzite Al1−x−yScxGdyN${\rm Al}_{1-x-y}{\rm Sc}_x{\rm Gd}_y{\rm N}$ films, guided by density functional theory calculations. Wurtzite Al1−x−yScxGdyN${\rm Al}_{1-x-y}{\rm Sc}_x{\rm Gd}_y{\rm N}$ films have a high optical bandgap, enhanced piezoelectric ...
Julia L. Martin   +11 more
wiley   +1 more source

LEO satellite communication and navigation symbiosis positioning management based on signal of opportunity

open access: yesDianxin kexue, 2023
Communication and navigation symbiosis refers to the coexistence of these signals in the satellite ecological environment.For single-function low-orbit satellite constellations for positioning or communication, it is difficult to quickly perform ...
Jie SHEN   +6 more
doaj  

Atomic Tuning of Metal‐Support Interactions for Pathway‐Selective CO2 Photoreduction on TiO2

open access: yesAdvanced Science, EarlyView.
Single‐atom Fe and Cu catalysts anchored on TiO2 steer photocatalytic CO2 reduction toward distinct pathways. Fe sites favor rapid *CO desorption and selective CO formation, whereas Cu sites stabilize *CHO intermediates, enabling deep reduction and C─C coupling. Combined spectroscopy and DFT calculations reveal how metal–support interactions and oxygen
Dongyun Kim   +13 more
wiley   +1 more source

Redox‐Active NiOx‐Catalyzed Li+ Capture‐Extraction Strategy for tBP‐Free Spiro‐OMeTAD Enables Exceptional Damp‐Heat Stability in Perovskite Solar Cells

open access: yesAdvanced Science, EarlyView.
The redox‐active nature of NiOx enables ultrafast oxidative doping of spiro‐OMeTAD within seconds. Concurrently, NiOx‐Li+ coordination complexes formed during this redox process are selectively removed by filtration, effectively extracting residual Li+ ions from the film.
Yun Seop Shin   +19 more
wiley   +1 more source

Ni Single‐Atom Modulation of Ti‐O Covalency Boosts Ammonia Oxidation Electrocatalysis

open access: yesAdvanced Science, EarlyView.
A Ni single‐atom‐induced enhancement of Ti‐O covalency in Ni SAC@TiO2 generates abundant active sites and promotes selective NHx‐NHy mediated N2 evolution while suppressing poisonous NOx formation, achieving nearly doubled AOR activity with excellent durability.
Subhash Chandra Shit   +7 more
wiley   +1 more source

Positioning of Lightning Electromagnetic Radiation Sources With Satellite Constellations: Simulation and Preliminary Validation

open access: yesEarth and Space Science
Satellites, equipped with electromagnetic sensors, can detect and locate the lightning electromagnetic radiation sources (LERS) in the thunderstorm over the globe surface of the Earth, delivering data regarding occurrence time, geolocation, and intensity.
Xiao Li   +8 more
doaj   +1 more source

Transient Terahertz Oscillations During Photoinduced Polarization Topology Reconfiguration in Ferroelectric Superlattices

open access: yesAdvanced Science, EarlyView.
Terahertz resonances in crystalline heterostructures could close a spectral gap between conventional electronics and photonics while opening new windows on non‐equilibrium lattice dynamics. Femtosecond optical screening of the depolarization field in epitaxial PbTiO3/SrTiO3 superlattices launches a collective polar mode that oscillates near 1 THz and ...
Deepankar Sri Gyan   +13 more
wiley   +1 more source

Vacancy‐Suppressed Garnet Electrolytes for Durable Solid‐State Batteries

open access: yesAdvanced Science, EarlyView.
A Li/O‐rich sintering strategy effectively suppresses intrinsic lithium and oxygen vacancies in cubic garnet electrolytes, yielding a dense and stable microstructure. The vacancy‐controlled electrolyte exhibits enhanced interfacial and air stability, enabling long‐term solid‐state battery cycling and providing a general design principle for defect ...
Seokjae Hong   +20 more
wiley   +1 more source

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