Characterization of the Gel Phases of AlPO<sub>4</sub>-11 Molecular Sieve Synthesis by Solid-state NMR
Bibliographic record
Abstract
We have used several solid-state NMR techniques in conjunction with powder X-ray diffraction (XRD) and FT-Raman spectroscopy to characterize the structures of the intermediate phases of AlPO 4 -11 molecular sieve synthesis. The evolution of the gel phases as a function of crystallization time was followed by 31 P and 27 Al magic angle spinning (MAS) NMR to obtain information on the local environments of Al and P atoms and by powder XRD to detect the long range ordering of the gel samples. We have utilized 27 Al triple-quantum MAS (3QMAS) to gain additional resolution for monitoring the incorporation of different Al sites into the framework during the crystallization. 27 Al/ 31 P double resonance techniques such as cross polarization (CP), transfer of populations by double-resonance, and rotational echo double-resonance have been utilized to select the 31 P−O− 27 Al bonding connectivities within the gel phases. The 1 H → 31 P CP enables differentiation of the phosphorus sites in different phases coexisting in the same solid sample. FT-Raman spectroscopy also provides insight into the interactions between organic template and inorganic gel species as well as the evaluation of the pore system. The present work clearly demonstrates that the dipolar-coupling based double-resonance techniques can provide important connectivity information regarding the structures of the gels, which are not readily available from simple MAS experiments.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".