{"created":"2023-07-27T06:50:19.002079+00:00","id":43050,"links":{},"metadata":{"_buckets":{"deposit":"c66182d2-5754-4a50-abf3-3bc27f2a581a"},"_deposit":{"created_by":18,"id":"43050","owners":[18],"pid":{"revision_id":0,"type":"depid","value":"43050"},"status":"published"},"_oai":{"id":"oai:kanazawa-u.repo.nii.ac.jp:00043050","sets":["2812:2813:2837"]},"author_link":["69253","69254"],"item_9_biblio_info_8":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"1997-03","bibliographicIssueDateType":"Issued"},"bibliographicPageStart":"125p.","bibliographicVolumeNumber":"1995-1996","bibliographic_titles":[{"bibliographic_title":"平成8(1996)年度 科学研究費補助金 基盤研究(C) 研究成果報告書"},{"bibliographic_title":"1996 Fiscal Year Final Research Report","bibliographic_titleLang":"en"}]}]},"item_9_creator_33":{"attribute_name":"著者別表示","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{}],"nameIdentifiers":[{},{}]}]},"item_9_description_21":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"低周波大電流電磁パルス波を用いた地下数百〜数kmまでの深地下探査レーダ開発の一環として、本研究課題においては以下の研究を行なった。\n1.地表面付近に置かれたアンテナから放射された電磁パルス波は、数百〜数kmの地下から反射してくる際に、その強度が著しく減衰してしまう。そのため、同じく地表面付近に置かれたサーチコイルによる受信磁界波形において、アンテナからの直接波のように比較的強い信号と同時に、地中からの反射波のような弱い信号の波形を正しく捕らえることのできる広ダイナミックレンジ波形捕捉受信器を設計、制作し、テスト信号を入力することによりその動作を確認した。これは、入力信号の絶対強度の大小により自動的に4段階(0〜36dB)のゲインコントロールを行い、12ビットA/D変換器を用いて約100dBのダイナミックレンジが得られるもので、実際の電磁パルス波地中伝搬実験で得られる観測波形から地中反射波のみを抜き出すために有用である。\n2.一方、地表付近のアンテナから放射された低周波(10k〜100kHz)電磁パルス波の地中伝搬および埋没物体からの反射の様子を知るために、FDTD(時間領域差分)法によりMaxwell方程式を時空間で差分化し、損失地下媒質中での電磁波伝搬のシミュレーションを行なうコードを開発した。2次元および3次元モデルを用い、埋没物体の散乱断面積の評価やガウスパルス波の地中伝搬特性の解析を行なった。その結果、特に3次元モデルでは自由空間および損失大地を含む実際に近い媒質モデルでのシミュレーションが可能になり、大地上に置かれたループアンテナから放射されたパルス波に対する、地下数百mに置かれた金属板からの反射波の地上での受信波形をシミュレートし、アンテナからの直接波と反射波の分解可能性など、反射波を受信するための条件を検討した。","subitem_description_type":"Abstract"},{"subitem_description":"This research has been carried out over two years on the basis of following two categories :\n(1) Development of a wave form capture with a wide (100 dB) dynamic range to observe weak electromagnetic echoes from the deep underground\n(2) Computer simulation on the propagation of a VLF electromagnetic pulse in the deep underground\nAs for item (1), we have developed a wave form capture with a wide dynamic range to measure weak VLF echoes reflected from the deep underground which would be received simultaneously with a much stronger electromagnetic pulse directly coming from the transmitter. By using an automatic gain controlling circuit to select the gain (from 0 to 36 dB) of an signal amplifier, a total 100-dB dynamic range has been realized with a single 12-bit (66 dB) A/D converter. The developed wave form capture has been confirmed to work well for several test signals.\nAs for item (2), a three-dimensional computer simulation code using a finite-difference timedomain (FDTD) method, has been developed to compute underground propagation of an electromagnetic wave radiated from a loop antenna on the ground. Using this simulation code, we have evaluated VLF scattering cross sections of metal plates of various sizes buried in the deep (-800m) underground. The results have been applied to estimate the loop current necessary to radiate a VLF radar pulse which produces its echo from the deep underground strong enough to be received by a search coil magnetometer on the ground.","subitem_description_type":"Abstract"}]},"item_9_description_22":{"attribute_name":"内容記述","attribute_value_mlt":[{"subitem_description":"研究課題/領域番号:07650421, 研究期間(年度):1995-1996","subitem_description_type":"Other"},{"subitem_description":"出典：「低周波大電流電磁パルス波の地中伝搬実験」研究成果報告書　課題番号07650421\n(KAKEN：科学研究費助成事業データベース（国立情報学研究所）)\n　　　本文データは著者版報告書より作成","subitem_description_type":"Other"}]},"item_9_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.24517/00049397","subitem_identifier_reg_type":"JaLC"}]},"item_9_publisher_17":{"attribute_name":"公開者","attribute_value_mlt":[{"subitem_publisher":"金沢大学工学部"}]},"item_9_relation_28":{"attribute_name":"関連URI","attribute_value_mlt":[{"subitem_relation_name":[{"subitem_relation_name_text":"https://kaken.nii.ac.jp/search/?qm=50019775"}],"subitem_relation_type_id":{"subitem_relation_type_id_text":"https://kaken.nii.ac.jp/search/?qm=50019775","subitem_relation_type_select":"URI"}},{"subitem_relation_name":[{"subitem_relation_name_text":"https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07650421/"}],"subitem_relation_type_id":{"subitem_relation_type_id_text":"https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07650421/","subitem_relation_type_select":"URI"}},{"subitem_relation_name":[{"subitem_relation_name_text":"https://kaken.nii.ac.jp/report/KAKENHI-PROJECT-07650421/076504211996kenkyu_seika_hokoku_gaiyo/"}],"subitem_relation_type_id":{"subitem_relation_type_id_text":"https://kaken.nii.ac.jp/report/KAKENHI-PROJECT-07650421/076504211996kenkyu_seika_hokoku_gaiyo/","subitem_relation_type_select":"URI"}}]},"item_9_version_type_25":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_ab4af688f83e57aa","subitem_version_type":"AM"}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2017-12-21"}],"displaytype":"detail","filename":"TE-PR-NAGANO-I-kaken 1997-125p.pdf","filesize":[{"value":"5.0 MB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"TE-PR-NAGANO-I-kaken 1997-125p.pdf","url":"https://kanazawa-u.repo.nii.ac.jp/record/43050/files/TE-PR-NAGANO-I-kaken 1997-125p.pdf"},"version_id":"741c971f-83d0-4c6f-a19c-291d415ebe60"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"research report","resourceuri":"http://purl.org/coar/resource_type/c_18ws"}]},"item_title":"低周波大電流電磁パルス波の地中伝搬実験","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"低周波大電流電磁パルス波の地中伝搬実験"},{"subitem_title":"Propagation Experiment of VLF Electromagnetic Pulses in the Deep Underground","subitem_title_language":"en"}]},"item_type_id":"9","owner":"18","path":["2837"],"pubdate":{"attribute_name":"公開日","attribute_value":"2017-12-21"},"publish_date":"2017-12-21","publish_status":"0","recid":"43050","relation_version_is_last":true,"title":["低周波大電流電磁パルス波の地中伝搬実験"],"weko_creator_id":"18","weko_shared_id":-1},"updated":"2023-07-27T14:53:40.502992+00:00"}