Synthesis of MCM-48 Silica Using a Gemini Surfactant with a Rigid Spacer
Bibliographic record
Abstract
Gemini surfactant p -phenylenedimethylenebis( n -hexadecyldimethylammonium) dibromide (abbreviated C 16 -DMB-C 16, with DMB = p -CH 2 C 4 H 6 CH 2 ) with a rigid spacer was found to produce cubic MCM-48 silica mesophase by temperature-induced phase transition from the MCM-41 hexagonal phase. The synthesis involved two steps, a precipitation stage at room temperature for a period of time t 1, followed by an aging step at higher temperature for a period of time t 2 . The synthesis was optimized for particular combinations of t 1 and t 2 periods. The phase transformation was studied under various pH and temperature conditions. Although it was observed that ethanol partitioning induced, at least partially, the formation of the cubic structure, the transformation was also shown to be influenced by the degree of silicate polymerization. The MCM-48 silica prepared under optimized conditions exhibited a type IV nitrogen adsorption isotherm, a BET surface area of 1164 m 2 /g, and a narrow pore size distribution with a maximum at 2.5 nm.
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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 | 0.001 |
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".