Articles you may be interested inSmall-angle neutron scattering studies of polybutadiene/polystyrene blends as a function of pressure and microstructure: Comparison of experiment and theory Effect of the Onsager coefficient and internal relaxation modes on spinodal decomposition in the high molecular isotopic blend polystyrene/deuteropolystyrene studied with small angle neutron scattering Early state of spinodal decomposition studied with small angle neutron scattering in the blend deuteropolystyrene and polyvinylmethylether: A comparison with the Cahn-Hilliard-Cook theory J. Chem. Phys. 97, 8775 (1992); 10.1063/1.463347 Shear stabilization of critical fluctuations in bulk polymer blends studied by small angle neutron scattering J. Chem. Phys. 93, 795 (1990); 10.1063/1.459533 Investigation of the phase diagram and critical fluctuations of the system polyvenylmethylether and d polystyrene with neutron small angle scatteringFor the isotopic blend of polystyrene (PS)/deutero PS (M w = 10 6 dalton), the Flory-Huggins interaction parameter X(rp,n was determined by means of the structure factor SeQ) measured by small angle neutron scattering (SANS). From X(rp,n, the miscibility gap and the corresponding spinodal line was evaluated with a critical temperature of 130 ·C. Decomposition in the miscibility gap is extremely slow due to the critical slowing down and due to a glass transition 30 K below Te. Furthermore, the transition ofthe homogeneous blend between two temperatures was investigated by SANS. The interdiffusion constant of the two isotopic species was determined from these experiments. Our results approach the Cahn-Hilliard-Cook theory only in the limit of small wavenumbers of the fluctuations. Three weeks after annealing the sample, demixing was observed in the predicted two-phase region.J. Chem. Phys. 93 (11).

The excitation functions for the production of long range alpha-particles, gamma-rays, and electron pairs by the bombardment of F 19 by protons have been observed simultaneously up to a bombarding energy of 1.5 Mev. The long range alpha and pair curves exhibit resonance peaks superimposed on a background of increasing intensity with increasing bombarding energy. Approximate coincidence in two instances of pair and alpha-resonances suggests that full range alphas and the short range alphas preceding pair emission can be products of competing modes of decay of the same intermediate states of Ne 20 . This in turn suggests that the state of O 16 which decays by pair emission has the same parity (even) as the ground states of O 16 and thus that the pair emission can be due to ordinary electromagnetic forces. The absolute yields of the various processes have been measured and a discussion of the measurement of high energy gamma-ray and pair yields by means of electroscopes is given. The large ratio of gamma-ray yields to long range alpha and pair yields previously observed has been confirmed.

The isotope shift between 197Au (stable) and 195Au (T1,2=183 d) was determined by resonance fluorescence and polarization spectroscopy in the 6s2S1/2-6pZP1/2, 2 =267.6nm line. The result is 5v 195'19v= -2.9(2) GHz corresponding to a change of the mean-square charge radius by 6(r2) 195't97 =0.063(9)fm z. The sample was confined to a resonance cell heated to temperatures of up to 1500 ~

The isotope shift between 197Atl (stable) and the radioactive Au isotopes 19~ 191Au, 192Au and 193Au were determined by resonance fluorescence spectroscopy in the 6sZS1/2-6pZP1/2. 2=267.6nm line. The unstable Au isotopes were produced at the ISOLDE mass separator at CERN. The nuclei were investigated semi on-line in a resonance vessel, heated to 1,400~The results are (~v 190'197= -11.12(39) GHz, 6V191'197=--9.67(12) GHz, GHz, 0V193't97=--6.29(ll) GHz, corresponding to a change of the mean-square charge radius by 6~r2) 19~ =0.261(12) fm 2, 6(r2)19a,197=0.227(5)fm2, 6(rz)192,197=0.195 (5)