例句與造句

1. For example, the proton NMR spectrum changes from a sharp singlet at 4.2 ppm at higher temperatures to a complex pattern at lower temperatures.
2. With a simple proton NMR spectrum comprising two signals due to the 2 aromatic hydrogens ( 2H ) and four methyl groups ( 12H ), durene is used as an internal standard.
3. At pH = 2 the carboxylic end-groups are protonated and the wheel shuttles back and forth between them as evidenced by the presence of just two aromatic viologen protons in the proton NMR spectrum.
4. In the proton NMR spectrum for RuClH ( CO ) ( PPh 3 ) 3 there is doublet of triplets ( two sets of three peaks, with the peaks in the ratio 1 : 2 : 1 ) at about-7ppm.
5. The 108?angle of each regular pentagon is close to the ideal bond angle of 109.5?for an symmetry, evidenced by its proton NMR spectrum in which all hydrogen atoms appear at a single chemical shift of 3.38 ppm.
6. It's difficult to find proton nmr spectrum in a sentence. 用proton nmr spectrum造句挺難的
7. The proton NMR spectrum for this compound shows that the phenyl protons are shifted downfield compared to a proton position in benzene itself ( chemical shift position for the ortho proton is 9.49 ppm ), suggesting the presence of a diamagnetic ring current and thus aromaticity.