Preface

The Symposium on Polymer Diffraction was part of the 188th National Meeting of the American Chemical Society held in Philadelphia, Pennsylvania, in August 1984 under the sponsorship of the Cellulose, Paper, and Textile Division and the Division of Polymeric Material: Science and Engineering.     

Preface

<正>This special issue contains the selected invited talks given at the 2016 Dalian International Workshop on Nuclear Physics(2016DIWNP)held in Dalian,China,from 20th to 23rd of July 2016.The 2016DIWNP was organized by colleagues from 12 institutions and universities including Bulgarian Academy of Sciences(Sofia,Bulgaria),China Institute of Atomic Energy(Beijing,China),East China Normal University(Shanghai,China),Institute of Modern Physics,CAS(Lanzhou,China),Lanzhou University(Lanzhou,China),     

Preface

In this article, a family of periodic quantum Hamiltonians, that is subject to a closure condition is considered. In the context of the factorization method, we address the question of non-uniqueness of the governing superpotentials and study an alternative factorization to generate new hierarchies of potentials.