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  1. Free, publicly-accessible full text available May 1, 2025
  2. The integration of onboard computing capabilities with unmanned aerial vehicles (UAV) has gained significant attention in recent years as part of mobile computing paradigms such as mobile edge computing (MEC), fog computing, and mobile cloud computing. To enhance the performance of airborne computing, networked airborne computing (NAC) aims to interconnect UAVs through direct flight-to-flight links, with UAVs sharing resources with each other. However, despite the growing interest in NAC and UAV-based computing, existing studies rely heavily on numerical simulations for performance evaluation and lack realistic simulators and hardware testbeds. To fill this gap, this paper presents the development of two NAC platforms: a realistic simulator based on ROS and Gazebo, and a hardware testbed with multiple UAVs communicating and sharing computing resources. Through simulation and real flight tests with two computation applications, we evaluate the platforms and examine the impact of mobility on NAC performance. Our findings offer valuable insights into NAC and provide guidance for future advancements. 
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  3. Free, publicly-accessible full text available October 1, 2024
  4. Free, publicly-accessible full text available August 8, 2024
  5. Abstract Electroluminescence efficiencies and stabilities of quasi-two-dimensional halide perovskites are restricted by the formation of multiple-quantum-well structures with broad and uncontrollable phase distributions. Here, we report a ligand design strategy to substantially suppress diffusion-limited phase disproportionation, thereby enabling better phase control. We demonstrate that extending the π-conjugation length and increasing the cross-sectional area of the ligand enables perovskite thin films with dramatically suppressed ion transport, narrowed phase distributions, reduced defect densities, and enhanced radiative recombination efficiencies. Consequently, we achieved efficient and stable deep-red light-emitting diodes with a peak external quantum efficiency of 26.3% (average 22.9% among 70 devices and cross-checked) and a half-life of ~220 and 2.8 h under a constant current density of 0.1 and 12 mA/cm 2 , respectively. Our devices also exhibit wide wavelength tunability and improved spectral and phase stability compared with existing perovskite light-emitting diodes. These discoveries provide critical insights into the molecular design and crystallization kinetics of low-dimensional perovskite semiconductors for light-emitting devices. 
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    Free, publicly-accessible full text available December 1, 2024
  6. Probe is the core component of an optical scanning probe microscope such as scattering-type scanning near-field optical microscopy (s-SNOM). Its ability of concentrating and localizing light determines the detection sensitivity of nanoscale spectroscopy. In this paper, a novel plasmonic probe made of a gradient permittivity material (GPM) is proposed and its nanofocusing performance is studied theoretically and numerically. Compared with conventional plasmonic probes, this probe has at least two outstanding advantages: First, it doesn't need extra structures for surface plasmon polaritons (SPPs) excitation or localized surface plasmon resonance (LSPR), simplifying the probe system; Second, the inherent nanofocusing effects of the conical probe structure can be further reinforced dramatically by designing the distribution of the probe permittivity. As a result, the strong near-field enhancement and localization at the tip apex improve both spectral sensitivity and spatial resolution of a s-SNOM. We also numerically demonstrate that a GPM probe as well as its enhanced nanofocusing effects can be realized by conventional semiconductor materials with designed doping distributions. The proposed novel plasmonic probe promises to facilitate subsequent nanoscale spectroscopy applications. 
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