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Zhang, Boyu

Publications and source records attributed to Zhang, Boyu.

10 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Towards robust laser beam propagation in atmospheric turbulence

High-fidelity optical propagation through the atmosphere is essential for free-space optical technologies, including laser-based remote sensing and optical communication. However, atmospheric turbulence severely distorts beams and compromises system performance. In this work, we employ hypergeometric-Gaussian (HyGG) vortex beams as probes to characterize and mitigate atmospheric turbulence. Using over 250,000 experimental and simulated frames, we show that refining the power spectrum density (PSD) can reduce numerical prediction errors by up to 79.8%. Concurrently, experimental observations supported by numerical simulations demonstrate that HyGG beams exhibit superior turbulence resilience across multiple metrics compared to conventional Gaussian beams, particularly in their ability to withstand over 5 times stronger turbulence while maintaining similar intensity fluctuations. These dual investigations, on both turbulence mitigation and robust beam solutions, converge to form a unified strategy for enhancing free-space optical system performance. Collectively, our findings provide new insights into light–turbulence interactions and highlight the practical utility of vortex beams under atmospheric conditions.

Zhang, Boyu↗
DOE OSTI2023

Two‐Color Amplified Spontaneous Emission from Auger‐Suppressed Quantum Dots in Liquids

Abstract Colloidal quantum‐dot (QD) lasing is normally achieved in close‐packed solid‐state films, as a high QD volume fraction is required for stimulated emission to outcompete fast Auger decay of optical‐gain‐active multiexciton states. Here a new type of liquid optical‐gain medium is demonstrated, in which compact compositionally‐graded QDs (ccg‐QDs) that feature strong suppression of Auger decay are liquefied using a small amount of solvent. Transient absorption measurements of ccg‐QD liquid suspensions reveal broad‐band optical gain spanning a wide spectral range from 560 (green) to 675 nm (red). The gain magnitude is sufficient to realize a two‐color amplified spontaneous emission (ASE) at 637 and 594 nm due to the band‐edge (1S) and the excited‐state (1P) transition, respectively. Importantly, the ASE regime is achieved using quasicontinuous excitation with nanosecond pulses. Furthermore, the ASE is highly stable under prolonged excitation, which stands in contrast to traditional dyes that exhibit strong degradation under identical excitation conditions. These observations point toward a considerable potential of high‐density ccg‐QD suspensions as liquid, dye‐like optical gain media that feature readily achievable spectral tunability and stable operation under intense photoexcitation.

Li, Xueyang↗
DOE OSTI2023

High-Spatial-Resolution Quantitative Chemomechanical Mapping of Organic Composite Cathodes for Sulfide-Based Solid-State Batteries

Understanding the chemo-mechanical behaviors of electrodes, particularly at the electrode/electrolyte interfaces, is critical for improving the performance of all-solid-state batteries. However, due to the instability of electrolyte materials under ambient conditions, such characterizations are challenging, particularly for sulfide-based all-solid-state batteries. Herein, by combining time-of-flight secondary-ion mass spectroscopy (ToF-SIMS) and in-SEM nanoindentation measurements, a systematic quantitative investigation of the chemo-mechanical behaviors of pyrene-4,5,9,10-tetraone (PTO) /Li 6 PS 5 Cl composite cathodes is carried out. Chemical and quantitative mechanical information of the composite cathode were collected with high spatial resolution after developing and implementing an air-free characterization protocol. By directly connecting the Young’s modulus and hardness with the Li distribution in the composite cathode, a comprehensive chemo-mechanical mapping of the PTO/ Li 6 PS 5 Cl composite cathode has been established. Furthermore, this work improves our knowledge of the critical chemo-mechanical phenomena that occur at the cathode/electrolyte interfaces in all-solid-state batteries.

25 ENERGY STORAGE↗
DOE OSTI2022

Integrated simulation, machine learning, and experimental approach to characterizing fracture instability in indentation pillar-splitting of materials

Measuring fracture toughness of materials at small scales remains challenging due to limited experimental testing configurations. A recently developed indentation pillar-splitting method has shown promise of improved flexibility in fracture toughness measurements at the microscale, partly due to the occurrence of an unusual fracture instability, i.e., a transition from stable to unstable crack propagation. In spite of growing interest in this method, the underlying mechanism of this phenomenon is yet to be elucidated. Furthermore, we provide a comprehensive description of fracture instability in indentation pillar-splitting by combining in situ experiments with high-fidelity simulations based on cohesive zone and J-integral methods. In addition, a machine-learning-based solution for predicting the critical indentation load of fracture instability is established through Gaussian processes regression for broad use of this method by the community.

36 MATERIALS SCIENCE↗
DOE OSTI2022

High-surface-area corundum nanoparticles by resistive hotspot-induced phase transformation

Abstract High-surface-area α-Al 2 O 3 nanoparticles are used in high-strength ceramics and stable catalyst supports. The production of α-Al 2 O 3 by phase transformation from γ-Al 2 O 3 is hampered by a high activation energy barrier, which usually requires extended high-temperature annealing (~1500 K, > 10 h) and suffers from aggregation. Here, we report the synthesis of dehydrated α-Al 2 O 3 nanoparticles (phase purity ~100%, particle size ~23 nm, surface area ~65 m 2 g −1 ) by a pulsed direct current Joule heating of γ-Al 2 O 3 . The phase transformation is completed at a reduced bulk temperature and duration (~573 K, < 1 s) via an intermediate δʹ-Al 2 O 3 phase. Numerical simulations reveal the resistive hotspot-induced local heating in the pulsed current process enables the rapid transformation. Theoretical calculations show the topotactic transition (from γ- to δʹ- to α-Al 2 O 3 ) is driven by their surface energy differences. The α-Al 2 O 3 nanoparticles are sintered to nanograined ceramics with hardness superior to commercial alumina and approaching that of sapphire.

Deng, Bing (ORCID:0000000305308410)↗
DOE OSTI2022

Can Li: A Career in Catalysis

Prof. Can Li is distinguished for his seminal achievements in fundamental and applied researches in catalysis, especially in advancing the characterization of catalysts and catalytic reactions related to solar energy conversion and fine chemical synthesis. The scope of his research is wide ranging, and he is leading some of the fields. This account highlights his major scientific achievements in advancing the fundamental sciences of characterizing catalysts and understanding the mechanisms of catalytic reactions by developing in situ spectroscopic techniques (e.g., infrared (IR), ultraviolet (UV), Raman, space- and time-resolved spectroscopies and photoelectric imaging), and applying the obtained knowledge in the rational design and synthesis of catalysts for practical applications in photocatalytic, electrocatalytic and photoelectrocatalytic water splitting and CO 2 reduction, chiral synthesis in nanoreactors and ultradeep desulfurization of fuels, and fine chemical synthesis. In particular, his demonstration of the kiloton scale solar fuel production project will be introduced as a successful model for converting fundamental science into practical and impactful applications to convert CO 2 and water into solar fuels. This account also highlights his services to the catalysis communities and international collaborations for promoting catalysis science worldwide.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗