Dynamic Mechanical Properties of Polyoxymethylene III

Abstract

A 6-dimensional grand unified theory with the compact space having the topology of a real projective plane, i.e., a 2-sphere with opposite points identified, is considered. The space is locally flat except for two conical singularities where the curvature is concentrated. One supersymmetry is preserved in the effective 4d theory. The unified gauge symmetry, for example SU(5) , is broken only by the non-trivial global topology. In contrast to the Hosotani mechanism, no adjoint Wilson-line modulus associated with this breaking appears. Since, locally, SU(5) remains a good symmetry everywhere, no UV-sensitive threshold corrections arise and SU(5)-violating local operators are forbidden. Doublettriplet splitting can be addressed in the context of a 6d N = 2 super Yang-Mills theory with gauge group SU(6). If this symmetry is first broken to SU(5) at a fixed point and then further reduced to the standard model group in the above non-local way, the two light Higgs doublets of the MSSM are predicted by the group-theoretical and geometrical structure of the model.

Dynamic mechanical studies on the crystal dispersion using ultradrawn polyethylene films

“…The significance of the vertical shift factor was discussed in terms of Nagamatsu's34 and Miki's approaches. 35,36 The former approach is based on the temperature dependence of amorphous entropic elasticity supplemented by the volume effect of the amorphous regions, while the latter approach takes into account the temperature dependence of crystal elasticity, based on a theory by Wada37 and Okano,38 of a smearing-out effect on the intermolecular potential within a crystal lattice. However, Suehiro et al23 reported that both of the approaches give a much smaller temperature dependence of the vertical shift factor than that required for fitting the experimental data.…”

Dynamic Mechanical Properties of Polyoxymethylene, IV

“…14 A remarkable anisotropy was found for the temperature dependence of rigidity of the drawn and oriented polyoxymethylene. 15 The anisotropy was interpreted on the concept of the "smearingout effect" of a component c66 of the elastic modulus tensor of the crystal due to the incoherent torsional lattice vibrations. 2 1 However, as shown in Figure 10, the vertical shift was unnecessary for the superpositions of G' and G" curves of the original samples of single crystals at temperatures below about 100°C and 115 ° C re spec ti vel y.…”

“…If these distortions spread only along the normal direction to the c-axis of the crystal, the component c66 should decrease effectively with increasing temperature. 15 The temperature variation of the rigidity of the crystal does not occur in the single crystals, because the single crystals include less lattice defects than the melt-crystallized polyoxymethylene. As shown in Figure 10, the rigidity decreases with increasing temperature above about 50°C for the heat-treated single crystal mat.…”

“…The temperature variation of the magnitude of the vertical shift has shown a remarkable anisotropy in the a relaxation region of the drawn and oriented polyoxymethylene. 15 • One of the purposes of this work is to examine whether the vertical shifts are necessary for the superposition of the dispersion curves of the single crystals of polyoxymethylene. This paper is therefore concerned also with the origin of the vertical shift along the logarithmic rigidity axis.…”