【摘要】：自1945年核磁共振(Nuclear Magnetic Resonance, NMR)現(xiàn)象被發(fā)現(xiàn)以來,核磁共振技術(shù)的發(fā)展猶如一棵常青樹,目前已經(jīng)成為應(yīng)用最為廣泛的分析技術(shù)之一。核磁共振技術(shù)之所以能具有如此強(qiáng)大的生命力主要是由于其能提供大量的化學(xué)結(jié)構(gòu)信息和動(dòng)力學(xué)信息,而高分辨率的譜圖正是提供這些信息的基礎(chǔ)。隨著核磁共振在代謝組學(xué)等領(lǐng)域的不斷發(fā)展應(yīng)用,如何自動(dòng)地獲得高分辨率的核磁共振譜圖越來越受到人們的重視,這也是核磁共振波譜儀研發(fā)的一個(gè)重要挑戰(zhàn)和機(jī)遇。 本論文從實(shí)驗(yàn)和數(shù)據(jù)處理兩個(gè)方面,開展自動(dòng)獲取高分辨核磁共振譜圖的研究工作。在具有自主知識(shí)產(chǎn)權(quán)的核磁共振波譜儀上,實(shí)現(xiàn)了自動(dòng)獲取高分辨核磁共振譜圖所需的三項(xiàng)關(guān)鍵技術(shù)：自動(dòng)勻場(chǎng)方法,自動(dòng)相位校正方法以及自動(dòng)基線校正方法,并在此基礎(chǔ)上提出了一些更優(yōu)化的改進(jìn)方案。 在自動(dòng)化核磁共振實(shí)驗(yàn)的研究工作中,我們針對(duì)高分辨核磁共振實(shí)驗(yàn)必須具備的前提條件之一——均勻的靜磁場(chǎng)展開研究。在自主開發(fā)的核磁共振波波譜儀中實(shí)現(xiàn)了各種自動(dòng)勻場(chǎng)方法包括基于搜索算法的自動(dòng)勻場(chǎng)方法,一維和三維梯度勻場(chǎng)方法,及結(jié)合線形的梯度勻場(chǎng)方法。并在此基礎(chǔ)上,提出了一些改進(jìn)方法,如：在三維梯度勻場(chǎng)方法中,采用了改進(jìn)的脈沖序列,使得譜儀可以利用XY勻場(chǎng)線圈來產(chǎn)生相位編碼梯度,從而實(shí)現(xiàn)了在普通探頭上的三維梯度勻場(chǎng)；此外,針對(duì)梯度勻場(chǎng)中勻場(chǎng)電流值越界和三維梯度勻場(chǎng)時(shí)間過長(zhǎng)的兩個(gè)問題,分別提出了相應(yīng)的解決方案。 在自動(dòng)數(shù)據(jù)處理方面,我們首先實(shí)現(xiàn)了核磁共振數(shù)據(jù)處理軟件中的常規(guī)算法,并在此基礎(chǔ)上發(fā)展了若干改進(jìn)方法,包括一種適用性和準(zhǔn)確性都非常高的自動(dòng)相位校正方法,以及可以適用于基線失真較大譜圖的自動(dòng)基線校正方法。新的自動(dòng)相位校正方法采用了粗調(diào)和細(xì)調(diào)相結(jié)合的方案,在粗調(diào)過程中利用了“基線-譜峰”分界點(diǎn)差異最小化的方法獲得一個(gè)大致準(zhǔn)確的校正結(jié)果,基于這個(gè)結(jié)果判斷出各個(gè)譜峰的特性,即將譜圖中的譜峰區(qū)分為正峰、負(fù)峰和畸變峰。然后利用最小化自定義的負(fù)值懲罰函數(shù)進(jìn)行細(xì)調(diào),從而獲得更準(zhǔn)確的自動(dòng)相位校正結(jié)果。最后,通過實(shí)驗(yàn)驗(yàn)證出新的自動(dòng)相位校正方法不僅適用于各種NMR譜圖,而且?guī)缀醪皇苄旁氡取⒒�失真等因素的影響。表明此方法不僅普適性強(qiáng),而且具有很好的魯棒性以及準(zhǔn)確性。新的自動(dòng)基線校正方法的基礎(chǔ)是改進(jìn)的基線識(shí)別算法和迭代的基線模型構(gòu)建算法。其中,改進(jìn)的基線識(shí)別算法不僅結(jié)合了三種常用的基線識(shí)別算法,而且還利用譜峰輪廓擬合的方法來準(zhǔn)確地識(shí)別出譜圖中的寬峰信號(hào)。而在迭代的基線模型構(gòu)建算法中,我們不僅利用了識(shí)別出的基線區(qū)間,還在迭代的過程中自動(dòng)地尋出譜圖中譜峰重疊非常嚴(yán)重區(qū)間中的“準(zhǔn)基線點(diǎn)”,利用這些“準(zhǔn)基線點(diǎn)”我們可以構(gòu)建出更符合實(shí)際情況的基線模型,從而得到更好的基線校正結(jié)果。實(shí)驗(yàn)證明這種新的自動(dòng)基線校正方法能夠更有效地處理譜峰密集和基線失真嚴(yán)重的復(fù)雜NMR譜圖。
[Abstract]:Nuclear magnetic resonance (NMR) has been developed as a evergreen tree since the nuclear magnetic resonance (NMR) phenomenon in 1945, and has become one of the most widely used analytical techniques. The nuclear magnetic resonance technology can have such strong vitality mainly because it can provide a large amount of chemical structure information and kinetic information, and the high-resolution spectrogram is the basis for providing these information. With the development of nuclear magnetic resonance in the field of metabolism, how to obtain the high-resolution NMR spectrum is more and more important, which is also an important challenge and opportunity for the R & D of the nuclear magnetic resonance spectrometer. In this paper, from the aspects of experiment and data processing, an automatic acquisition of the high-resolution nuclear magnetic resonance spectrum is carried out. The three key technologies required for automatic acquisition of high-resolution nuclear magnetic resonance (NMR) spectrum are realized on a nuclear magnetic resonance spectrometer with independent intellectual property rights: an automatic uniform field method, an automatic phase correction method, and an automatic base line correction. Methods, and on the basis of this, some more optimization improvements are put forward Protocol. In the study of automated nuclear magnetic resonance experiments, we have one of the prerequisites for high-resolution nuclear magnetic resonance experiments _ a uniform static magnetic field The field development research has been carried out in the self-developed nuclear magnetic resonance wave spectrometer, which comprises the following steps: an automatic uniform field method based on a search algorithm, a three-dimensional gradient uniform field method for peacekeeping, and a linear ladder in that method of three-dimensional gradient uniform field, an improved pulse sequence is used, so that the spectrometer can use the XY uniform field coil to generate the phase encode gradient, so that the three-dimensional gradient on a common probe is realized, in addition, that problem that the uniform field current value of the gradient uniform field and the time of the three-dimensional gradient uniform field are too long are put forward. In the aspect of automatic data processing, we first realized the conventional algorithm in the nuclear magnetic resonance data processing software, and on the basis of this, we developed a number of improved methods, including a very high degree of applicability and accuracy. Automatic phase correction method, and can be applied to a baseline distortion larger spectrum map The new automatic phase correction method adopts the scheme of coarse and fine phase modulation and fine phase modulation. In the coarse tuning process, the method of minimizing the difference of the 鈥渂aseline-spectrum peak鈥，

本文編號(hào)：2349206