With an average density higher than the nuclear density, neutron stars (NS) provide a unique testground for nuclear physics, quantum chromodynamics (QCD), and nuclear superfluidity. Determination of the fundamental interactions that govern matter under such extreme conditions is one of the major unsolved problems of modern physics, and -since it is impossible to replicate these conditions on Earth -a major scientific motivation for SKA. The most stringent observational constraints come from measurements of NS bulk properties: each model for the microscopic behaviour of matter predicts a specific density-pressure relation (its 'Equation of state', EOS). This generates a unique mass-radius relation which predicts a characteristic radius for a large range of masses and a maximum mass above which NS collapse to black holes. It also uniquely predicts other bulk quantities, like maximum spin frequency and moment of inertia. The SKA, in Phase 2 and particularly in Phase 2 will, thanks to the exquisite timing precision enabled by its raw sensitivity, and surveys that dramatically increase the number of sources: 1) Provide many more precise NS mass measurements (high mass NS measurements are particularly important for ruling out EOS models); 2) Allow the measurement of the NS moment of inertia in highly relativistic binaries such as the Double Pulsar; 3) Greatly increase the number of fast-spinning NS, with the potential discovery of spin frequencies above those allowed by some EOS models; 4) Improve our knowledge of new classes of binary pulsars such as black widows and redbacks (which may be massive as a class) through sensitive broad-band radio observations; and 5) Improve our understanding of dense matter superfluidity and the state of matter in the interior through the study of rotational glitches, provided that an ad-hoc campaign is developed.Advancing Astrophysics with the Square Kilometer Array

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A series of poly(phthalazinone ether sulfone ketone) (PPESK) copolymers containing different component ratios of bis(4-fluorodiphenyl) ketone and bis(4-chlorodiphenyl)sulfone with respect to a certain amount of 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one were synthesized by polycondensation. Glass transition temperatures of these polymers were adjusted from 263°C to 305°C by changing the ratios of reactants. Gas permeability and selectivity of the dense membranes of the polymers for three kinds of gases (CO 2 , O 2 , and N 2 ) were determined at different temperatures. The result indicated that the membrane of PPESK (S/K ϭ 1/1, mol ratio) had an excellent gas separation property. Permeability of the polymer membranes for CO 2 , O 2 , and N 2 was P CO 2 ϭ 4.121 barrier, P O 2 ϭ 0.674 barrier, and P N 2 ϭ 0.0891 barrier, respectively. Separation factors of ␣ O 2 /N and ␣ CO 2 /N 2 were 7.6 and 46, respectively. New material was made into a composite membrane with silicone rubber for blocking up leaks and defects on the surface of its nonsymmetrical membrane. As a result of the test, permeability of the composite membrane was J O 2 ϭ 7.2 ϫ 10 Ϫ6 cm 3 (STP) cm Ϫ2 S Ϫ1 cm Ϫ1 Hg and J N 2 ϭ 0.99 ϫ 10 Ϫ6 cm 3 (STP) cm Ϫ2 S Ϫ1 cm Ϫ1 Hg, whereas the ␣ O 2 /N 2 was still higher than 7. These showed that PPESKs had a bright prospect as the potential membrane material for high-temperature gas separation.