Gas-phase nuclear magnetic relaxation in Xe129 revisited
Bibliographic record
Abstract
In this contribution gas-phase Xe129 spin-lattice relaxation time measurements are extended to conditions (pressure, temperature, magnetic-field strength, isotope composition) not previously used. It is shown that wall effects become apparent at densities below ∼20 amagat, and that these become dominant below ∼3 amagat. A significant new discovery from field-dependent studies is that, in addition to the previously identified field-independent spin–rotation relaxation operative in the bulk gas, there is a contribution from the modulation of the chemical shift that depends on the square of the applied magnetic-field strength. The weak temperature dependence of the relaxation times can be understood in terms of the opposite temperature coefficients of the field-independent and field-dependent contributions to the relaxation. The spin–rotation contribution and its temperature dependence are calculated and found to be in good agreement with the experimental data. The low field, low density limit for the relaxation time is 56.3±2.6 hr⋅amagat at 295 K in the absence of wall effects.
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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 | 0.000 |
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".