Numerical and experimental investigation of the dynamics of ultrasound contrast agents excited at higher multiples of their natural resonance frequency
Bibliographic record
Abstract
In this work the Hoff model for microbubble oscillations was used together with bifurcation diagrams to investigate microbubble behavior for a range of the system control parameters (driving frequency and pressure, microbubble size and shell parameters). We have shown that if the microbubble sizes are optimized so that their resonance frequency is a fraction of the sonication frequency (1/3, 1/4...), above a certain pressure threshold, the microbubbles can emit higher order subharmonics at (1/3, 2/3...) of the sonication frequency. Experimental results (using Artenga and in-house made lipid microbubbles with a 25 MHz, 30 cycle pulse using 0.1-2.5 MPa pressures) showed subpopulations of the microbubbles that were able to show this behaviour by scattering ultrasound according to the theoretical predictions (e.g. having two frequency maxima for subharmonics at f/3 and 2f/3). The ring-down analysis of the natural free oscillations of these microbubbles confirmed the theoretical resonance predictions.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| 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 | 0.000 |
| 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".