Anomalous ultrasonic transport in phononic crystals with overlapping Bragg and hybridization gaps
Bibliographic record
Abstract
Many of the interesting properties of phononic crystals are due to the existence of band gaps, which may arise from a number of different mechanisms. These include Bragg scattering as well as hybridization effects, the latter occurring when there are strong scattering resonances that hybridize with a propagating mode of the embedding medium. In this talk, we investigate the interaction between Bragg and hybridization effects on the band gap properties of 2D phononic crystals consisting of nylon rods arranged in a triangular lattice and immersed in water. The lattice constant and rod diameter were chosen to ensure that both mechanisms occur in the same frequency range. The scattering resonances of the nylon rods can be tuned in frequency by varying the temperature, enabling fine control of the overlap between hybridization and Bragg effects. The dispersion relations and transmission coefficient were measured experimentally from the phase and amplitude of transmitted ultrasonic pulses and calculated theoretically by finite element simulations. Strikingly unusual dispersion effects are observed, revealing a novel way of tuning band gap properties. These remarkable characteristics are explained by the competition between two co-existing propagation modes, reflecting strong coupling between scattering resonances of the rods.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".