Modulus Dispersion Research Articles

Determination of theJψ(3100)-nucleon total cross section using modulus dispersion relations

Using the energy dependence of photoproduction data from Cornell, Fermilab, and SLAC, we calculate the phase of the forward elastic $\frac{J}{\ensuremath{\psi}}(3100)\ensuremath{-}N$ scattering amplitude by applying modulus dispersion relations. The total cross section thus obtained suggests that the $\frac{J}{\ensuremath{\psi}}(3100)$ is a hadron. A possible threshold due to production of a new quantum number is also discussed. Similar analysis is carried out for the $\ensuremath{\varphi}p$ forward elastic amplitude.

On the phase of γp → π0p in the forward direction

A calculation of the phase of the forward amplitude for γp → π 0p is presented. It has been done by means of the so called modulus dispersion relations. The pion photoproduction amplitudes for isospin I = 1 2 and I = 3 2 are also given.

Investigations of the dynamic mechanical properties of some polyamides

AbstractThe damping, resonant frequency, and dynamic elastic storage modulus of five polyamides have been investigated at resonant frequencies ranging from 100 to 2000 cycles/sec. at temperatures in the 100 to 450°K. region. Specimens of poly(hexamethyleneadipamide) containing 0, 0.9, 3.3, and 6.4 wt.‐% water were studied and it was found that with increasing water content: the loss peak and associated modulus dispersion at 170°K. in the dry material decreased; the loss peak and modulus dispersion at 370°K. in the dry material shifted to lower temperatures reaching a value of 280°K. for 6.4% water; a third damping peak appeared at 240 to 245°K. and the modulus in the 150 to 250°K. region increased while above and below this range the reverse was true. A poly(hexamethylene adipamide) specimen containing 10.5 wt.‐% methanol exhibited one broad peak at about 255 to 260°K. Dry specimens of poly(hexamethylene sebacamide), poly(decamethylene sebacamide), 17% N‐methylated poly(decamethylene sebacamide), and 58% N‐methylated poly(decamethylene sebacamide) were also investigated. For the latter three specimens the principal amorphous transition shifted from 340 to 285°K. and the area under the loss peak increased greatly in going from 0 to 58% N‐methylation, while the low temperature transition remained at 160 to 170°K. essentially unchanged. Of the five polymers studied the 17% N‐methylated poly(decamethylene sebacamide) exhibited the highest apparent modulus in the 110 to 160°K. region; and at all temperatures below the principal amorphous transition this material had a higher modulus than the unmethylated parent polymer.