Surfaces in 4-manifolds and their mapping class groups

A surface in a smooth 4-manifold is called flexible if, for any diffeomorphism ? on the surface, there is a diffeomorphism on the 4-manifold whose restriction on the surface is ? and which is isotopic to the identity. We investigate a sufficient condition for a smooth 4-manifold M to include flexible knotted surfaces, and introduce a local operation in simply connected 4-manifolds for obtaining a flexible knotted surface from any knotted surface.     

Magnetic Alignment in Solid State and Temperature Hysteresis in Aqueous Tetrahydrofuran Solution for Tetrathiafulvaleno[18]annulenes

Tris(tetrathiafulvaleno)dodecadehydro[18]annulene‐hexaesters have a multi‐functionality that is very sensitive to small differences in the ester side‐chain. Self‐aggregation of the [18]annulenes in amphiphilic media such as THF–H₂O (v/v, 1:1) either produce a fibrous structure or result in temperature hysteresis of the color and ¹H NMR signals. This temperature hysteresis in solution is due to both strong self‐aggregation behavior and unique cluster formation in a binary solution of THF and water.     

Formation mechanism and luminescence appearance of Mn-doped zinc silicate particles synthesized in supercritical water

Luminescence appearance of Mn-doped zinc silicate (Zn₂SiO₄:Mn²⁺, ZSM) formed in supercritical water at 400 °C and 29 MPa at reaction times from 1 to 4320 min was studied in the relation to its phase formation mechanism. Appearance of luminescent ZSM from green emission by α-ZSM and yellow emission by β-ZSM occurred over the same time period during the onset of phase formation at a reaction time of 2 min. Luminescence appeared at a much lower temperature and at shorter reaction times than the conventional solid-state reaction. Needle-like-shaped α-ZSM was the most stable particle shape and phase in the supercritical water reaction environment and particles formed via two routes: a homogenous nucleation route and a heterogenous route that involves solid-state diffusion and recrystallization.