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完整後設資料紀錄
DC 欄位 | 值 | 語言 |
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dc.contributor.advisor | 張嘉升(Chia-Seng Chang) | |
dc.contributor.author | Wun-Cin Huang | en |
dc.contributor.author | 黃文勤 | zh_TW |
dc.date.accessioned | 2021-06-17T04:51:01Z | - |
dc.date.available | 2018-08-02 | |
dc.date.copyright | 2018-08-02 | |
dc.date.issued | 2018 | |
dc.date.submitted | 2018-07-31 | |
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dc.identifier.uri | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/71062 | - |
dc.description.abstract | 使用以單原子針為電子源的低能量點投影顯微鏡(point projection microscope, PPM in short)可以收取到樣品之高對比投影同軸電子全像圖(in-line hologram)。本篇論文中,我們使用PPM觀察懸空石墨烯表面(suspended graphene)的吸附物。本篇論文的工作,主要是為PPM找尋一套影像重建的方法,重建同軸電子全像圖,以得到高解析的樣品影像。第一部分,我們使用傳統全像術重建實驗全相圖,觀察到懸空石墨烯表面吸附物的結構與動態行為。然而,傳統電子全像術著名的Twin image問題使得重建影像殘留干涉條紋,大幅降低的影像解析度。為了解決Twin image問題,第二部分我們用模擬測試了transport intensity equation(TIE)方法的重建。TIE能夠用兩張或多張在些微不同樣品-屏幕間距記錄的全像圖,重建繞射平面上的相位。再藉由菲涅耳反向傳播(Fresnel backward propagation),可以計算出物體平面上的樣品穿透函數(transmission function)。模擬結果顯示TIE方法重建影像的解析度有大幅的提升。此外,我們也討論了樣品穿透函數振幅與相位的範圍以及實驗上信噪比可能會對重建造成的問題。 | zh_TW |
dc.description.abstract | High contrast projection in-line holograms of samples can be acquired by the low energy electron point projection microscope(PPM) based on a single-atom-tip(SAT) emitter. The main purpose of this work is to find an image reconstruction method for PPM, so high resolution images of sample can be obtained from reconstructed in-line holograms. In this thesis, we use PPM to investigate adsorbates on suspended graphene. In the first part, dynamics and structures of the adsorbates were reconstructed by a method of conventional digital holography. However, the resolution was apparently reduced because of a well-known twin-image problem. In the second part, a reconstruction method based on transport intensity equation (TIE) is tested by the simulation to solve the twin-image problem. Using two or more holograms recorded at slightly different sample-screen distances, the phase on the diffraction plane can be reconstructed by TIE. The exit wave in the object plane can then be computed by Fresnel backward propagation. In our simulation, the resolution of the images reconstructed by the TIE method is significantly improved. In additional, problems of reconstruction which caused by amplitude and phase of transmission function and the signal-to-noise ratio are discussed. | en |
dc.description.provenance | Made available in DSpace on 2021-06-17T04:51:01Z (GMT). No. of bitstreams: 1 ntu-107-R05222049-1.pdf: 3424765 bytes, checksum: f457e5c6d8615e6d656aa0c313670bc1 (MD5) Previous issue date: 2018 | en |
dc.description.tableofcontents | 口試委員會審定書………………………………………………………i
致謝 …………………………………………………………………ii 摘要 …………………………………………………………………iii Abstract ………………………………………………………………iv 目錄 ……………………………………………………………………v 圖目錄 ………………………………………………………………viii 表目錄 …………………………………………………………………x 第一章 緒論 …………………………………………………………1 第二章 文獻回顧 ……………………………………………………4 2.1 電子輻射破壞 …………………………………………4 2.2 PPM觀察石墨烯樣品 ……………………………………5 2.3 單原子針做為PPM電子源 ……………………………7 2.4 PPM投影全像圖的影像重建 ……………………………8 第三章 實驗儀器與步驟 ……………………………………………13 3.1 儀器介紹 ……………………………………………13 3.1.1超高真空抽氣系統 ……………………………13 3.1.2顯微平台 ………………………………………14 3.1.3成像系統 ………………………………………14 3.2 單原子針置備 ………………………………………15 3.3 石墨烯樣品置備 ……………………………………17 第四章 傳統全像術之影像重建 ……………………………………19 4.1傳統全像圖的模擬與影像重建方法 …………………19 4.1.1任意光源全像圖的模擬與影像重建方法 ……19 4.1.2點光源全像圖的模擬與影像重建方法 ………21 4.1.3有限取樣與快速傅立葉轉換 ………………22 4.2實驗全像圖之影像重建 ………………………………23 4.2.1表面吸附物聚集行為 ………………………23 4.2.2表面吸附物位移行為 ………………………25 第五章 TIE方法之影像重建 ………………………………………26 5.1 TIE的推導與適用範圍 ………………………………26 5.2 TIE為基礎全像術影像重建法 ………………………27 5.3 TIE為基礎全像術之數值模擬 ………………………29 5.3.1 實數物體 ……………………………………29 5.3.2 複數物體 ……………………………………31 第六章 結論與未來展望 ……………………………………………38 參考文獻 ……………………………………………………………39 | |
dc.language.iso | zh-TW | |
dc.title | 低能量電子點投影顯微鏡全像模擬與影像還原 | zh_TW |
dc.title | Holographic Simulations and Reconstructions of Low-energy Electron Point Projection Microscopy | en |
dc.type | Thesis | |
dc.date.schoolyear | 106-2 | |
dc.description.degree | 碩士 | |
dc.contributor.coadvisor | 黃英碩(Ing-Shouh Hwang) | |
dc.contributor.oralexamcommittee | 陳健群(Chien-Chun Chen) | |
dc.subject.keyword | 單原子針,低能量點投影顯微鏡,同軸電子全像圖,Twin image,transport intensity equation, | zh_TW |
dc.subject.keyword | single-atom-tip,low energy electron point projection microscope,in-line holograms,Twin image transport,intensity equation, | en |
dc.relation.page | 41 | |
dc.identifier.doi | 10.6342/NTU201802151 | |
dc.rights.note | 有償授權 | |
dc.date.accepted | 2018-07-31 | |
dc.contributor.author-college | 理學院 | zh_TW |
dc.contributor.author-dept | 物理學研究所 | zh_TW |
顯示於系所單位: | 物理學系 |
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