【正文】 磁共振高斯計(jì)方案設(shè)計(jì)與實(shí)驗(yàn) Magic Resonance Gaussian Plan Design and Experiment 學(xué) 院： 信息科學(xué)與工程學(xué)院 專 業(yè) 班 級(jí)： 測(cè)控技術(shù)與儀器 03 班 學(xué) 號(hào)： 學(xué) 生 姓 名： 指 導(dǎo) 教 師： （副教授） 2020 年 06 月密級(jí)：公開 I 摘 要 核磁共振理論誕生于 1946 年，經(jīng)過 60 多年的發(fā)展 ，核磁共振技術(shù) 己經(jīng)相當(dāng)成熟，用于建立以原子常數(shù)為尺度的磁場(chǎng)參量自然基準(zhǔn)，具 有測(cè)量精度高、受外界干擾小、信號(hào)穩(wěn)定清晰等其它方法無(wú)法比擬的優(yōu)勢(shì)。本文介紹了核磁共振理論原理，以及基于核磁共振方法的磁場(chǎng)測(cè)量系統(tǒng)的設(shè)計(jì)與實(shí)驗(yàn)。 本系統(tǒng)以邊緣振蕩器的設(shè)計(jì)以及核磁共振信號(hào)的提取為核心，經(jīng)過一系列的放大與濾波，進(jìn)而使用單片機(jī)控制 A/D 轉(zhuǎn)換器輸出，通過改變變?nèi)荻O管反向偏壓調(diào)整邊緣振蕩器的振蕩頻率，實(shí)現(xiàn)共振信號(hào)的搜索和跟蹤。根據(jù)拉莫爾進(jìn)動(dòng)公式轉(zhuǎn)換成待測(cè)磁場(chǎng)的磁感應(yīng)強(qiáng)度，使用串口調(diào)試助手顯示測(cè)量結(jié)果。 論文首先簡(jiǎn)述了核磁共振原理，并引出本文所采用的核磁共振實(shí)驗(yàn)方法：連續(xù)波方法。然后論文對(duì)具體裝置的實(shí) 現(xiàn)進(jìn)行了深入的剖析，這其中包括：磁場(chǎng)的構(gòu)建，電路部分和探頭部分纏繞線圈的方式。通過對(duì)比幾種產(chǎn)生均勻磁場(chǎng)方法的優(yōu)缺點(diǎn)，提出一種采用 H 型兩極磁體構(gòu)建均勻磁場(chǎng)的方法；并討論了具體的磁路設(shè)計(jì)，磁場(chǎng)仿真。電路部分采用一種基于邊限振蕩器檢測(cè)方法來提高檢測(cè)的靈敏度，描述了邊限振蕩器的原理，詳細(xì)介紹了振蕩器及檢測(cè)電路的實(shí)現(xiàn) 。 關(guān)鍵詞 :核磁共振 。邊緣振蕩器 。A/D 轉(zhuǎn)換 。頻率測(cè)量 II Abstract Nuclear magic resonance (NMR) theory was born in 1946, after more than 60 years of development has been quite mature, used to set up to the atom of the magic field parameters for constant scale natural benchmark, and has high precision measurement, the interference of small, stable clear signal and other methods of inparable advantage. This paper introduces the principle of magic resonance theory, and based on the nuclear magic resonance (NMR) method of the magic field measurement system design and experiment. This system to the edge of the oscillator design and nuclear magic resonance (NMR) signal for the extraction of core, after A series of amplifier and filter, and then using singlechip microputer control A/D converter output, through the change is reverse bias adjustment let diode edge of the oscillator oscillation frequency, realize the resonance of search and tracking signal. According to pull into the dynamic formula converted into Moore, for the magic field of magic induction strength, using a serial port debug assistant display measured results. It firstly briefly nuclear magic resonance (NMR) principle, and draw out this paper the nuclear magic resonance (NMR) experimental method: continuous wave method. And then to the realization of the specific device paper carried on the deep analysis, including: the construction of the magic field, the circuit of the part and probe the way around coil. By paring several to produce uniform magic field and the advantages and disadvantages of the methods, it is proposed that a H poles of mags uniform magic field construction method。 And discuss specific magic circuit design, magic field simulation. The circuit of the based on edge detection method to improve test oscillator sensitivity, describes the principle of edge oscillator, detailed introduces the oscillator and test the circuitry. Key words: Nuclear magic resonance (NMR)。 Edge oscillator。 Gaussian plans, A/D conversion。 Frequency measurements I 目 錄 摘 要 ....................................................................................................................... I Abstract ......................................................................................................................... II 第 1 章 緒論 .................................................................................................................1 核磁共振的發(fā)展與應(yīng)用介紹 .........................................................................1 核磁共振的國(guó)內(nèi)外現(xiàn)狀 .................................................................................2 磁場(chǎng)測(cè)量技術(shù)的發(fā)展趨勢(shì) ............................................................................3 研究的意義 .....................................................................................................4 課題研究的主要任務(wù)和預(yù)期目標(biāo) ................................................................5 主要任務(wù)及要求 .................................................................................5 預(yù)期目標(biāo) ..............................................................................................5 第 2 章 共振原理與方案論證 .....................................................................................6 原子核的磁性 ................................................................................................6 原子核在磁場(chǎng)中的行為 ................................................................................7 核磁共振現(xiàn)象和共振條件 ............................................................................8 影響核磁共振信號(hào)的因素 .............................................................................9 溫度 ......................................................................................................9 外磁場(chǎng)均勻性 ......................................................................................9 方案論證 ........................................................................................................9 檢測(cè)共振信號(hào)的方法 .........................................................................9 搜索核磁共振信號(hào)的方法 ................................................................12 磁場(chǎng)測(cè)量?jī)x的整體設(shè)計(jì)方案 ......................................................................12 小結(jié) ..............................................................................................................13 第 3 章 探頭與邊緣振蕩器 .......................................................................................14 探頭基本結(jié)構(gòu) ..............................................................................................14 邊緣振蕩器 ..................................................................................................15 功能概述 ............................................................................................15 電路設(shè)計(jì) ...........................................................................................16 小結(jié) .........................................................................