A 3.4 Micron Band in Magnesium Silicates: Preparation of Hydrocarbon-Silicate Condensates
Bibliographic record
Abstract
We have obtained infrared spectra of amorphous forsterite, Mg 2 SiO 4 , prepared in the presence of gaseous methane and find that hydrocarbon groups such as CH 2 and CH 3 can be incorporated in the silicate lattice. These chemical groups have little effect on the 10 μm silicate Si–O stretching band but introduce a 3.4 μm band similar, but not identical, to that seen in pure carbonaceous deposits including hydrogenated amorphous carbon. Absorption in this band is enhanced in the 2958 and 2873 cm -1 (3.38 and 3.48 μm) transitions of the CH 3 asymmetric and symmetric stretching vibrations, respectively. Additional absorption features identified with Si(CH 3 ) 1, 2, 3 and Si(CH 2 )Si groups have also been observed, and a band corresponding to the Si-phenyl stretch has been detected. We discuss the possibility that hydrocarbon-silicate grains may be a component of interstellar matter, particularly in the winds from asymptotic giant branch stars with mixed carbon-silicate chemistry.
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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".