{"id":396,"date":"2016-10-26T02:07:51","date_gmt":"2016-10-26T02:07:51","guid":{"rendered":"http:\/\/pages.charlotte.edu\/colloquium\/?p=396"},"modified":"2016-10-27T13:58:21","modified_gmt":"2016-10-27T13:58:21","slug":"friday-october-28th-at-200pm-conference-room","status":"publish","type":"post","link":"https:\/\/pages.charlotte.edu\/colloquium\/blog\/2016\/10\/26\/friday-october-28th-at-200pm-conference-room\/","title":{"rendered":"Friday, October 28th, at 2:00PM Fretwell 410"},"content":{"rendered":"<table>\n<tbody>\n<tr>\n<td><a href=\"http:\/\/zhangtgroup.weebly.com\/\">Teng Zhang<\/a>:\u00a0Mechanical and Aerospace Engineering, Syracuse University<\/td>\n<\/tr>\n<tr>\n<td>Title: Mathematical Models for Topological Defects in Graphene<\/td>\n<\/tr>\n<tr>\n<td>\n<p>Abstract:Topological defects such as disclination, dislocation and grain boundary are ubiquitous in large-scale fabricated graphene. Due to its atomic scale thickness, the deformation energy in a free\u00a0standing graphene sheet can be easily released through out-of- plane wrinkles which, if\u00a0controllable, may be used to tune the electrical and mechanical properties of graphene.<\/p>\n<p>In this talk, I will first demonstrate that a generalized von Karman equation for a flexible solid\u00a0membrane can be used to describe graphene wrinkling in the presence of topological defects. In\u00a0this framework, a given distribution of topological defects in a graphene sheet is represented as\u00a0an eigenstrain field which is determined from a Poisson equation and can be conveniently\u00a0implemented in finite element (FEM) simulations. Comparison with atomistic simulations\u00a0indicates that the proposed continuum model is capable of accurately predicting the atomic scale\u00a0wrinkles near disclination\/dislocation cores while also capturing the large scale graphene\u00a0configurations under specific defect distributions such as those leading to a sinusoidal surface\u00a0ruga or a catenoid funnel. A great challenge in designing arbitrarily curved graphene with\u00a0topological defects is that the defect distribution for a specific 3D shape of graphene membrane\u00a0is usually unknown, which is actually an inverse problem involving highly nonlinear\u00a0deformation. In the second part of my talk, I will show how to apply the phase field crystal\u00a0(PFC) method to search for a triangular lattice pattern with the lowest energy on a given curved\u00a0surface, which then serves as a good approximation of the graphene lattice structure conforming\u00a0to that surface.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Teng Zhang:\u00a0Mechanical and Aerospace Engineering, Syracuse University Title: Mathematical Models for Topological Defects in Graphene Abstract:Topological defects such as disclination, dislocation and grain boundary are ubiquitous in large-scale fabricated graphene. Due to its atomic scale thickness, the deformation energy in a free\u00a0standing graphene sheet can be easily released through out-of- plane wrinkles which, if\u00a0controllable, may [&hellip;]<\/p>\n","protected":false},"author":333,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":true,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[1],"tags":[],"class_list":["post-396","post","type-post","status-publish","format-standard","hentry","category-spring-2022"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p3kCtT-6o","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/pages.charlotte.edu\/colloquium\/wp-json\/wp\/v2\/posts\/396","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pages.charlotte.edu\/colloquium\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pages.charlotte.edu\/colloquium\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pages.charlotte.edu\/colloquium\/wp-json\/wp\/v2\/users\/333"}],"replies":[{"embeddable":true,"href":"https:\/\/pages.charlotte.edu\/colloquium\/wp-json\/wp\/v2\/comments?post=396"}],"version-history":[{"count":2,"href":"https:\/\/pages.charlotte.edu\/colloquium\/wp-json\/wp\/v2\/posts\/396\/revisions"}],"predecessor-version":[{"id":405,"href":"https:\/\/pages.charlotte.edu\/colloquium\/wp-json\/wp\/v2\/posts\/396\/revisions\/405"}],"wp:attachment":[{"href":"https:\/\/pages.charlotte.edu\/colloquium\/wp-json\/wp\/v2\/media?parent=396"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pages.charlotte.edu\/colloquium\/wp-json\/wp\/v2\/categories?post=396"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pages.charlotte.edu\/colloquium\/wp-json\/wp\/v2\/tags?post=396"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}