Synthesis of Dimensional Organic Networks as Energy Materials

Department of Energy Engineering (Energy Engineering)The study of chemical structure is crucial in chemistry and materials science. Materials structure can be classified in various ways, and the most familiar approach is to classify them according to the dimension of structure. For example, carbon composed of the same elements can be categorized into zero-dimensional (0D) fullerene, one-dimensional (1D) carbon nanotube, two-dimensional (2D) graphene, and three- dimensional (3D) diamond, but due to particular arrangements of atoms the properties are significantly different depending on the structural dimension. Bearing this in mind, many organic structures were created by designing the symmetry of the molecules and using the polymerization to control the size of the structure (bottom-up strategy). The synthesized organic structures showed applicability to various applications such as gas separation, storage, membrane, and catalysis, etc. depending on the structural dimension. However, covalently bonded organic structures are limited in some areas because they are thermally unstable and have low conductivity. This thesis presents the results of applying a fully-fused aromatic networks (FANs) structure to energy materials to overcome the aforementioned limitations. The fused-ring has no free torsional motion, allowing stable electron transfer and providing thermal and chemical stability. By using these properties, the iron particles were encapsulated in the 2D structure, which showed excellent activity as a semi-permanent oxygen reduction catalyst and the 3D structure exhibited high hydrogen storage with excellent thermal stability. In addition, a new type of 2D structure that introduces insights into how to design materials in organic structures for gas separation and storage. Based on these studies, it is shown that FANs can be a promising material for electrochemical catalysts, gas storage, separation by using advantage of excellent electron mobility and thermochemical stability. Furthermore, I also studied carbon material as a catalyst having excellent activity and good stability in the conversion of ethylbenzene into styrene.clos

Monomial Relization of Crystal Bases for Special Linear Lie Algebras

We give a new realization of crystal bases for finite dimensional irreducible modules over special linear Lie algebras using the monomials introduced by H. Nakajima. We also discuss the connection between this monomial realization and the tableau realization given by Kashiwara and Nakashima.Comment: 15 page

Young Wall Realization of Crystal Bases for Classical Lie Algebras

In this paper, we give a new realization of crystal bases for finite dimensional irreducible modules over classical Lie algebras. The basis vectors are parameterized by certain Young walls lying between highest weight and lowest weight vectors.Comment: 27page