Ultrabroadband single crystal composite transducers for underwater ultrasound
Bibliographic record
Abstract
Through the use of complex piezoelectric structures, it is possible to obtain resonant harmonics not observed in the usual oddharmonic response of a conventional structure. When combined with inherently broadband components, such as composites made with PMNPT single crystal material, this permits the realisation of ultrabroadband devices. In the work reported here, results from modelling indicate that a bandwidth improvement by a factor up to four is possible compared with standard piezoceramic transducers. Experimental validation of this theoretical finding has taken place. This validation required a three-stage development process. The first stage involved careful selection of material and full characterisation using the commercial PRAP code (TASI Technical, Ontario, Canada). The output data were then used in modelling to simulate the behaviour of the bulk PMN-PT and good correlation was established. The second stage involved the fabrication of several composites with different PMN-PT volume fractions and adjustment of the model parameters to reduce disagreements between experiment and theory. The new parameters were then utilised in the third stage which involved acoustic stack design and optimisation. Several single crystal composite multilayer transducers, designated PAT-UBB-SC, were subsequently made. Operating with centre frequencies around 600 kHz and apertures of 10 mm x 15 mm, pulse-echo tests have shown a -6 dB relative bandwidth up to 125%, very close to the predicted 135%.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".