Heteronuclear Spin Decoupling under CryogenicMagic-Angle-Spinning Dynamic NuclearPolarization Conditions
Bibliographic record
Abstract
Heteronuclear decoupling is an essential element in the solid-state magic-angle spinning (MAS) Dynamic nuclear polarization (DNP) experiments involving low gamma (γ) nuclei like 13C and 15N coupled to protons. Under the constraints of limited (<100 kHz) maximum radio frequency (RF) amplitude and intermediate (30-45 kHz) spinning frequencies, imposed by the cryogenic DNP setup, the typically utilized heteronuclear decoupling schemes like TPPM and SPINAL-64 suffer from near rotary-resonance recoupling (R3). Here, we demonstrate the effectiveness of the refocused continuous-wave (rCW) decoupling sequence for heteronuclear 1H decoupling near the R3 regime under DNP conditions. We compare the performance of rCWApA decoupling with the widely used SPINAL-64 scheme and show a significant improvement in the heteronuclear decoupling efficiency, confirmed through T2' evaluations. The superior decoupling efficiency of rCWApA stems from its half-wave symmetry in the RF interaction frame, which enables effective decoupling of first and second-order effective heteronuclear coupling Hamiltonian, even at low RF amplitude levels and hence minimizing R3 effects better than any other decoupling scheme.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".