Browsing by Author "Zheng, Xueyan"
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- House on the CliffZheng, Xueyan (Virginia Tech, 2017-06-26)Color is both physical and perceptual. We see color, we feel color, and we dream of color. For the color study, I constructed the perspective drawings of the house as graphic compositions with no materiality. The application of primary colors to the drawings transformed the walls, ceiling, and floor into colored planes, which are common elements of concrete painting and pure Euclidean space, as explored by de Stijl and Rietveld through the medium of architecture. Aesthetic pleasure, following on my own judgment, is the final determining intention.Design of a house situated on an Appalachian cliff overlooking a lake 100 feet below. The program is intended to suit a young couple with the desire to escape urban life.
- Regioselective Synthesis of Cellulose EstersZheng, Xueyan (Virginia Tech, 2014-07-14)Cellulose is an extraordinarily abundant polymer that can be harvested and purified from trees and other renewable sources. Cellulose derivatives have been widely used as coatings, optical films, fibers, molded objects, and matrices for controlled release. The properties of cellulose derivatives are not only affected by the degree of substitution, but also by the position of substitution. In order to establish the structure-property relationships of cellulose derivatives, it is of great importance to impart regioselectivity into functionalized cellulose. However, regioselective substitution of cellulose is extremely challenging, especially in the synthesis of regioselectively functionalized cellulose esters due to the unstable ester bond under aqueous alkaline or acid conditions. In this dissertation, the main objective is to search for new tools to synthesize regioselectively substituted cellulose esters, to understand how structural changes impact properties and performance, and thus to design cellulose derivatives delivering high performance. Several strategies for regioselective preparation of cellulose esters are discussed in detail. The obtained regioselective cellulose esters were fully characterized analytically.