Compression behavior of dense <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi mathvariant="normal">H</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mtext>−</mml:mtext><mml:mi>He</mml:mi></mml:mrow></mml:math> mixtures up to 160 GPa
Bibliographic record
Abstract
We have studied the compression behavior of ${\mathrm{H}}_{2}\text{\ensuremath{-}}\mathrm{He}$ mixtures in comparison with pure ${\mathrm{H}}_{2}$ and He using powder synchrotron x-ray diffraction, and we present the pressure-volume (PV) compression data of ${\mathrm{H}}_{2}\text{\ensuremath{-}}\mathrm{He}$ mixtures to 160 GPa. The results indicate that both ${\mathrm{H}}_{2}$ and He in ${\mathrm{H}}_{2}\text{\ensuremath{-}}\mathrm{He}$ mixtures remain in hcp to the maximum pressure studied, yet they develop a substantial level of lattice distortion in the (100) plane, most profound in He-rich solids and below 66 GPa. The measured PV data also indicate the softening of an He (or ${\mathrm{H}}_{2}$) -rich lattice upon increasing the level of the guest ${\mathrm{H}}_{2}$ (or He) concentration. We suggest that the observed softening and lattice distortion are due to a substitutional incorporation of ${\mathrm{H}}_{2}$ (guest) molecules into the basal plane of the hcp-He (host) lattice, and thereby reflect the miscibility between ${\mathrm{H}}_{2}$ and He in ${\mathrm{H}}_{2}\text{\ensuremath{-}}\mathrm{He}$ mixtures. Interestingly, solid He exhibits a lesser degree of preferred orientation in ${\mathrm{H}}_{2}\text{\ensuremath{-}}\mathrm{He}$ mixtures than in pure He, likely due to the presence of solid ${\mathrm{H}}_{2}$ disturbing the crystalline ordering of He-rich solids. Finally, the present PV compression data of ${\mathrm{H}}_{2}$-rich and He-rich solids to 160 GPa deviate from those of pure ${\mathrm{H}}_{2}$ and pure He above \ensuremath{\sim}70 and 45 GPa respectively, providing new constraints for the development of the equation of state for ${\mathrm{H}}_{2}\text{\ensuremath{-}}\mathrm{He}$ mixtures for planetary models.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".