Structural Unfreezing and Endothermic Effects in Liquids, <i>β</i>-<scp>d</scp>-Fructose
Bibliographic record
Abstract
Both structural unfreezing and irreversible endothermic change between different molecular states of a material can occur on heating its liquid state and produce a double sigmoid-shaped endotherm in its apparent heat capacity, C p . In such a case, the usual calorimetry is unable to distinguish between the molecular mechanisms of the two endothermic contributions. We report that this distinction can be made by measuring C p and the complex heat capacity,, simultaneously in a temperature-modulated scanning mode. When a sigmoid-shaped increase is observed in both C p and of a liquid, the underlying process is structural unfreezing. But, when this increase is observed in normal scanning and not in the temperature-modulated mode, the underlying process is either irreversible or too slow, compared to the modulation period. The method has been used for resolving the nature of tautomeric transformation in liquid β - d -fructose. Simultaneous C p and measurements show that, for normal scanning, C p increases in a sigmoid-shaped manner with hysteresis, but for temperature-modulated scanning, the real component of C p does not increase in this manner (i.e., the reversible component of the heat flow shows neither a sigmoid-shaped increase nor hysteresis). Therefore, the sigmoid-shaped C p increase observed in normal scanning indicates an endothermic transformation in the β - d -fructose liquid at T > T g and not unfreezing of tautomeric transformation on the time scale of heating.
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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 | 0.000 |
| 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".