rocsa cosy dna rna d2o dosy meta commenting cpmg xwinnmr vconv magnet avance raw-data pulse-programming referencing nmrdraw isotope data-quality sensitivity solubility cryoprobe high-field_nmr felix shifts hmbc prosol lcnmr degradation intermediate stereochemistry j-hmbc salt complex database spectra signal-to-noise solvent-suppression gmapsys gradient-shimming cyana rate spin position line tcu damage amplifier stator rotor vnmrj procpar module file topspin postscript isomer olefin deuterium shims small-molecule propane pulse nutation solvent lock organic-chemistry cyclohexane analysis conformation concept selective field-strength structure-ensemble wanted cation scalar-coupling fastmf peak-integration polymer dynamics error modelfree hydrogen-bond peak-picking data-analysis bibliography data-format states-tppi integer float rdc pymol visualization liquids nucleic-acid microsoft-windows simulation relaxation-matrix demonstrations