Fourier Transform Nuclear Magnetic Resonance Spectroscopy of Commercial Polysiloxanes

Abstract

Multinuclear Fourier transform nmr spectroscopy is shown to be a potentially useful technique for the evaluation of commercial polysiloxanes. H, ²⁹Si: and ¹³C nmr spectra are reported of the precursor solutions for RTV silicones. The ¹³C show the increased presence of an unidentified material in unacceptable lots of one of the two precursor solutions.     

Synthetic DNA and Biology (Nobel Lecture)

Most of the significant work has been summarized in a number of reviews and articles. In these there was, of necessity, a good deal of simplification and omission of detail…. With the passage of time, even I find myself accepting such simplified accounts. F Sanger^[1]     

Sodium-23 Nuclear Magnetic Resonance Spectroscopy

With the availability of Fourier transform spectrometers, ²³Na-NMR spectroscopy has become an important tool. It affords direct insight into solvation and ion pairing phenomena, both in organic and in bio-inorganic systems. Monitoring the chemical shifts and linewidths of ²³Na signals gives access to binding constants, reorientational correlation times and the microdynamics of the sodium coordination shell. The binding of other cations can also be studied by ²³Na-NMR spectroscopy, in competition experiments.     

Birth of Neutrino Astrophysics (Nobel Lecture)

The KamiokaNDE experiment for the observation of proton decay, an array of photomultipliers containing over 3 000 tons of water, allowed the observation of charged particles travelling faster than the velocity of light in water. The subsequently developed Super‐KamiokaNDE could be used to measure the amounts, the path, the energies, and the oscillation parameters of neutrinos, generated either by supernova explosions in the sun, or in the atmosphere. This work was awarded the 2002 Nobel Prize in Physics.