{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/23885"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/23885","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Structure and melting of small metal particles observed by stem microdiffraction","abstract":"The structure of solvent deposited (Au, Au-Ag, Pt) and vapor deposited (Cu) metal particles •1040 Awas swdied by electron microdiffraction in a S1EM. A CCD array recorded the microdiffraction pattems with high sensitivity and dynamic range, and low noise Microdiffraction pattems were classified according to whether they had distinct Bragg peaks, or were diffuse. Patterns with distinct Bragg peaks showed low rates of twinning, with an upper bound of •14±3% in the case of Au-Ag particles. Diffuse patterns indicate that many of the particles are highly disordered, •88% in the case of Au particles. The effects of the electron beam on Pt particles were sllldied further. Crystalline Pt particles up to 40 A in diameter became disordered after exposures ranging from less than a second up to 40 minutes. Disordered particles' diffraction patterns were dynamic, with flickers of intensity lasting •15 msec (the resolution of the video tape). Pt particles on an amorphous C substrate remained disordered ... 20 min before recrystallizing. The dynamic nature and persistance of the disordered state are reminiscent of Ajayan and Marks's quasimelting theory.","abstract_html":"The structure of solvent deposited (Au, Au-Ag, Pt) and vapor deposited (Cu) metal particles •1040 Awas swdied by electron microdiffraction in a S1EM. A CCD array recorded the microdiffraction pattems with high sensitivity and dynamic range, and low noise Microdiffraction pattems were classified according to whether they had distinct Bragg peaks, or were diffuse. Patterns with distinct Bragg peaks showed low rates of twinning, with an upper bound of •14±3% in the case of Au-Ag particles. Diffuse patterns indicate that many of the particles are highly disordered, •88% in the case of Au particles. The effects of the electron beam on Pt particles were sllldied further. Crystalline Pt particles up to 40 A in diameter became disordered after exposures ranging from less than a second up to 40 minutes. Disordered particles' diffraction patterns were dynamic, with flickers of intensity lasting •15 msec (the resolution of the video tape). Pt particles on an amorphous C substrate remained disordered ... 20 min before recrystallizing. The dynamic nature and persistance of the disordered state are reminiscent of Ajayan and Marks's quasimelting theory.","abstract_has_math":false,"creators":["Contrata, Walter"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Mochel, J.M."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-16T18:31:03Z","date_published":"2011-05-16T18:31:03Z","updated_at":"2026-07-22T22:25:22Z","subjects":["small metal particles","electron microdiffraction STEM","Bragg peaks","structure of deposited metal particles"],"languages":["en"],"rights":["1992 Walter Contrata"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["3471708"],"render_values":[{"text":"3471708","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/23885","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Mochel, J.M."]},{"key":"dc:creator","label":"Author","values":["Contrata, Walter"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-16T18:31:03Z","10000-01-01","1992"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["small metal particles","electron microdiffraction STEM","Bragg peaks","structure of deposited metal particles"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1992 Walter Contrata"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["3471708","http://hdl.handle.net/2142/23885"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The structure of solvent deposited (Au, Au-Ag, Pt) and vapor deposited (Cu) metal particles •1040 Awas swdied by electron microdiffraction in a S1EM. A CCD array recorded the microdiffraction pattems with high sensitivity and dynamic range, and low noise Microdiffraction pattems were classified according to whether they had distinct Bragg peaks, or were diffuse. Patterns with distinct Bragg peaks showed low rates of twinning, with an upper bound of •14±3% in the case of Au-Ag particles. Diffuse patterns indicate that many of the particles are highly disordered, •88% in the case of Au particles. The effects of the electron beam on Pt particles were sllldied further. Crystalline Pt particles up to 40 A in diameter became disordered after exposures ranging from less than a second up to 40 minutes. Disordered particles' diffraction patterns were dynamic, with flickers of intensity lasting •15 msec (the resolution of the video tape). Pt particles on an amorphous C substrate remained disordered ... 20 min before recrystallizing. The dynamic nature and persistance of the disordered state are reminiscent of Ajayan and Marks's quasimelting theory.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-05-16T18:31:03Z No. of bitstreams: 1 1992_Contrata.pdf: 3107927 bytes, checksum: 048fbb93b06143477921c9e4b8f84e00 (MD5)","Made available in DSpace on 2011-05-16T18:31:03Z (GMT). No. of bitstreams: 1 1992_Contrata.pdf: 3107927 bytes, checksum: 048fbb93b06143477921c9e4b8f84e00 (MD5) Previous issue date: 1992","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-05-16T18:31:04Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:12:52-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["Structure and melting of small metal particles observed by stem microdiffraction"]}]}],"canonical_facts":{"dc:contributor":["Mochel, J.M."],"dc:creator":["Contrata, Walter"],"dc:date":["2011-05-16T18:31:03Z","10000-01-01","1992"],"dc:description":["The structure of solvent deposited (Au, Au-Ag, Pt) and vapor deposited (Cu) metal particles •1040 Awas swdied by electron microdiffraction in a S1EM. A CCD array recorded the microdiffraction pattems with high sensitivity and dynamic range, and low noise Microdiffraction pattems were classified according to whether they had distinct Bragg peaks, or were diffuse. Patterns with distinct Bragg peaks showed low rates of twinning, with an upper bound of •14±3% in the case of Au-Ag particles. Diffuse patterns indicate that many of the particles are highly disordered, •88% in the case of Au particles. The effects of the electron beam on Pt particles were sllldied further. Crystalline Pt particles up to 40 A in diameter became disordered after exposures ranging from less than a second up to 40 minutes. Disordered particles' diffraction patterns were dynamic, with flickers of intensity lasting •15 msec (the resolution of the video tape). Pt particles on an amorphous C substrate remained disordered ... 20 min before recrystallizing. The dynamic nature and persistance of the disordered state are reminiscent of Ajayan and Marks's quasimelting theory.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-05-16T18:31:03Z No. of bitstreams: 1 1992_Contrata.pdf: 3107927 bytes, checksum: 048fbb93b06143477921c9e4b8f84e00 (MD5)","Made available in DSpace on 2011-05-16T18:31:03Z (GMT). No. of bitstreams: 1 1992_Contrata.pdf: 3107927 bytes, checksum: 048fbb93b06143477921c9e4b8f84e00 (MD5) Previous issue date: 1992","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-05-16T18:31:04Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:12:52-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"],"dc:identifier":["3471708","http://hdl.handle.net/2142/23885"],"dc:language":["en"],"dc:rights":["1992 Walter Contrata"],"dc:subject":["small metal particles","electron microdiffraction STEM","Bragg peaks","structure of deposited metal particles"],"dc:title":["Structure and melting of small metal particles observed by stem microdiffraction"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:22Z"}