{"_buckets": {"deposit": "3a77ade2-a069-47a4-8c10-2181a9f3d18e"}, "_deposit": {"id": "8378", "owners": [], "pid": {"revision_id": 0, "type": "depid", "value": "8378"}, "status": "published"}, "_oai": {"id": "oai:nagoya.repo.nii.ac.jp:00008378", "sets": ["642"]}, "author_link": ["23556", "23557"], "item_12_alternative_title_19": {"attribute_name": "その他のタイトル", "attribute_value_mlt": [{"subitem_alternative_title": "氷微惑星の熱史および化学組成と力学的性質の進化", "subitem_alternative_title_language": "ja"}]}, "item_12_biblio_info_6": {"attribute_name": "書誌情報", "attribute_value_mlt": [{"bibliographicIssueDates": {"bibliographicIssueDate": "1998-03-25", "bibliographicIssueDateType": "Issued"}}]}, "item_12_date_granted_64": {"attribute_name": "学位授与年月日", "attribute_value_mlt": [{"subitem_dategranted": "1998-03-25"}]}, "item_12_description_4": {"attribute_name": "抄録", "attribute_value_mlt": [{"subitem_description": "The present thesis discusses evolution of the temperature, chemical composition, tensile stress and strength of icy planetesimals. The physical properties relevant to the evolution are examined in §2 including 1) the thermal conductivity, 2) the density and 3) the tensile strength. The physical properties of the ice discussed here include the activation energy of evolving processes of volatile molecules, and the effective latent heat of crystallization of amorphous H2O ice. The ice composition in the planetesimal is assumed to be amorphous H2O ice containing CO and CO2 as impurities. The basic equations and results of the numerical calculations are presented in §3. It is revealed that evolution forks into three ways depending on the initial chemical composition of the ice in the planetesimals. They are: 1) Endothermic case, where both CO and CO2 are contained in the ice in significant amount (∼ 10%): The crystallization degree of amorphous H2O ice is 40%, and CO trapped in the fraction of the ice is evolved at the final stage; this CO escapes outside of the planetesimal. On the other hand, CO2 condenses on the surfaces of the dust grains immediately after crystallization of amorphous H2O ice and is preserved. As the crystallization proceeds, sintering of CO2 and H2O takes place, and as a result the tensile strength is enhanced by three orders of magnitude. 2) Exothermic case, where the contents of both CO and CO2 are smaller (∼ 1%) than that of 1): Complete crystallization of the amorphous H2O ice takes place and runaway temperature increase occurs up to about 140K with increasing pressure gradient of CO and CO2 vapors released from the ice. Sintering of CO2 and H2O leads to the tensile strength increased by three orders of magnitude as in the case of 1). 3) No CO2 case, where CO is contained with considerable amount (∼ 1%), but the CO2 content is small (∼ 0%). The evolution in this case is essentially the same as in the case 2) but disruption of the planetesimal occurs depending on the magnitude of the activation energy of surface diffusion of H2O. If the activation energy is large, sintering of H2O proceeds slowly. Consequently the pressure gradient due to CO vapors exceeds the tensile strength at some point, leading to disruption of the planetesimals. Discussion is given in §4 on the implications of the results obtained in the previous sections. It is suggested that emergence of the diversity of planetary systems originates from the diversity of the composition of the ices in molecular clouds from which the plan- etary systems are formed. Namely, difference in the interstellar ice composition leads to different evolution described above. Discussion is given on the influences of the evolution of the tensile strength on collisional accretion to the cores of the Jovian planets. Condi- tions of the growth of the icy planetesimal are presented, and it is shown that the increase in the tensile strength in the icy planetesimals is necessary for forming the cores of the Jovian planets.", "subitem_description_language": "en", "subitem_description_type": "Abstract"}]}, "item_12_description_5": {"attribute_name": "内容記述", "attribute_value_mlt": [{"subitem_description": "北海道大学博士学位論文 学位の種類:博士(理学) (課程) 学位授与年月日:平成10年3月25日", "subitem_description_language": "ja", "subitem_description_type": "Other"}]}, "item_12_identifier_60": {"attribute_name": "URI", "attribute_value_mlt": [{"subitem_identifier_type": "HDL", "subitem_identifier_uri": "http://hdl.handle.net/2237/10119"}]}, "item_12_select_15": {"attribute_name": "著者版フラグ", "attribute_value_mlt": [{"subitem_select_item": "publisher"}]}, "item_12_text_14": {"attribute_name": "フォーマット", "attribute_value_mlt": [{"subitem_text_value": "application/pdf"}]}, "item_12_text_63": {"attribute_name": "学位授与年度", "attribute_value_mlt": [{"subitem_text_value": "1997"}]}, "item_access_right": {"attribute_name": "アクセス権", "attribute_value_mlt": [{"subitem_access_right": "open access", "subitem_access_right_uri": "http://purl.org/coar/access_right/c_abf2"}]}, "item_creator": {"attribute_name": "著者", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "城野, 信一", "creatorNameLang": "ja"}], "nameIdentifiers": [{"nameIdentifier": "23556", "nameIdentifierScheme": "WEKO"}]}, {"creatorNames": [{"creatorName": "Sirono, Sin-iti", "creatorNameLang": "en"}], "nameIdentifiers": [{"nameIdentifier": "23557", "nameIdentifierScheme": "WEKO"}]}]}, "item_files": {"attribute_name": "ファイル情報", "attribute_type": "file", "attribute_value_mlt": [{"accessrole": "open_date", "date": [{"dateType": "Available", "dateValue": "2018-02-19"}], "displaytype": "detail", "download_preview_message": "", "file_order": 0, "filename": "sirono.pdf", "filesize": [{"value": "530.9 kB"}], "format": "application/pdf", "future_date_message": "", "is_thumbnail": false, "licensetype": "license_note", "mimetype": "application/pdf", "size": 530900.0, "url": {"label": "sirono.pdf", "objectType": "fulltext", "url": "https://nagoya.repo.nii.ac.jp/record/8378/files/sirono.pdf"}, "version_id": "52c01384-aaaa-4391-bb23-264c03497d7e"}]}, "item_language": {"attribute_name": "言語", "attribute_value_mlt": [{"subitem_language": "eng"}]}, "item_resource_type": {"attribute_name": "資源タイプ", "attribute_value_mlt": [{"resourcetype": "doctoral thesis", "resourceuri": "http://purl.org/coar/resource_type/c_db06"}]}, "item_title": "A unified model of the thermal history of icy planetesimals : Evolution of their temperature, chemical composition and mechanical properties", "item_titles": {"attribute_name": "タイトル", "attribute_value_mlt": [{"subitem_title": "A unified model of the thermal history of icy planetesimals : Evolution of their temperature, chemical composition and mechanical properties", "subitem_title_language": "en"}]}, "item_type_id": "12", "owner": "1", "path": ["642"], "permalink_uri": "http://hdl.handle.net/2237/10119", "pubdate": {"attribute_name": "PubDate", "attribute_value": "2008-06-03"}, "publish_date": "2008-06-03", "publish_status": "0", "recid": "8378", "relation": {}, "relation_version_is_last": true, "title": ["A unified model of the thermal history of icy planetesimals : Evolution of their temperature, chemical composition and mechanical properties"], "weko_shared_id": -1}