共查询到20条相似文献,搜索用时 0 毫秒
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Prof. Xiaobo Qu Yihui Huang Hengfa Lu Tianyu Qiu Prof. Di Guo Dr. Tatiana Agback Prof. Vladislav Orekhov Prof. Zhong Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(26):10383-10386
Nuclear magnetic resonance (NMR) spectroscopy serves as an indispensable tool in chemistry and biology but often suffers from long experimental times. We present a proof-of-concept of the application of deep learning and neural networks for high-quality, reliable, and very fast NMR spectra reconstruction from limited experimental data. We show that the neural network training can be achieved using solely synthetic NMR signals, which lifts the prohibiting demand for a large volume of realistic training data usually required for a deep learning approach. 相似文献
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Dicheng Chen Zi Wang Prof. Di Guo Prof. Vladislav Orekhov Prof. Xiaobo Qu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(46):10391-10401
Since the concept of deep learning (DL) was formally proposed in 2006, it has had a major impact on academic research and industry. Nowadays, DL provides an unprecedented way to analyze and process data with demonstrated great results in computer vision, medical imaging, natural language processing, and so forth. Herein, applications of DL in NMR spectroscopy are summarized, and a perspective for DL as an entirely new approach that is likely to transform NMR spectroscopy into a much more efficient and powerful technique in chemistry and life sciences is outlined. 相似文献
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Pierre Laszlo 《Angewandte Chemie (International ed. in English)》1978,17(4):254-266
With the availability of Fourier transform spectrometers, 23Na-NMR spectroscopy has become an important tool. It affords direct insight into solvation and ion pairing phenomena, both in organic and in bio-inorganic systems. Monitoring the chemical shifts and linewidths of 23Na signals gives access to binding constants, reorientational correlation times and the microdynamics of the sodium coordination shell. The binding of other cations can also be studied by 23Na-NMR spectroscopy, in competition experiments. 相似文献
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Alarich Weiss 《Angewandte Chemie (International ed. in English)》1972,11(7):607-619
Various problems of solid-state chemistry can be solved by spectroscopic investigation of the nuclear magnetic resonance (NMR and NQR methods). This progress report presents a survey of the nature of the interactions in the crystal that underlie such measurements, of the observations in the spectrum, and of the information obtainable from it. The field of application of the methods covers both static and dynamic properties of solids. 相似文献
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On‐Line Monitoring of Chemical Reactions by using Bench‐Top Nuclear Magnetic Resonance Spectroscopy 下载免费PDF全文
Dr. E. Danieli Dr. J. Perlo Dr. A. L. L. Duchateau G. K. M. Verzijl Dr. V. M. Litvinov Prof. Dr. B. Blümich Dr. F. Casanova 《Chemphyschem》2014,15(14):3060-3066
Real‐time nuclear magnetic resonance (NMR) spectroscopy measurements carried out with a bench‐top system installed next to the reactor inside the fume hood of the chemistry laboratory are presented. To test the system for on‐line monitoring, a transfer hydrogenation reaction was studied by continuously pumping the reaction mixture from the reactor to the magnet and back in a closed loop. In addition to improving the time resolution provided by standard sampling methods, the use of such a flow setup eliminates the need for sample preparation. Owing to the progress in terms of field homogeneity and sensitivity now available with compact NMR spectrometers, small molecules dissolved at concentrations on the order of 1 mmol L?1 can be characterized in single‐scan measurements with 1 Hz resolution. Owing to the reduced field strength of compact low‐field systems compared to that of conventional high‐field magnets, the overlap in the spectrum of different NMR signals is a typical situation. The data processing required to obtain concentrations in the presence of signal overlap are discussed in detail, methods such as plain integration and line‐fitting approaches are compared, and the accuracy of each method is determined. The kinetic rates measured for different catalytic concentrations show good agreement with those obtained with gas chromatography as a reference analytical method. Finally, as the measurements are performed under continuous flow conditions, the experimental setup and the flow parameters are optimized to maximize time resolution and signal‐to‐noise ratio. 相似文献
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《Analytical letters》2012,45(19):2243-2250
Abstract Multinuclear Fourier transform nmr spectroscopy is shown to be a potentially useful technique for the evaluation of commercial polysiloxanes. H, 29Si: and 13C nmr spectra are reported of the precursor solutions for RTV silicones. The 13C show the increased presence of an unidentified material in unacceptable lots of one of the two precursor solutions. 相似文献
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Wolfgang von Philipsborn 《Angewandte Chemie (International ed. in English)》1971,10(7):472-490
In double resonance spectra, transitions between energy levels of a nuclear spin system are measured in the presence of two (or more) oscillating magnetic fields. Experiments of this nature form the basis of what is nowadays one of the most important techniques of NMR spectroscopy. Depending on the method selected, they can be used to unravel complex spectra, to measure hidden or weak resonances, or to determine the relative signs of coupling constants, as well as in stereochemical or kinetic studies. This wide and steadily growing range of applications of double resonance is described with the aid of specifilc examples. 相似文献
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Billion‐Fold Enhancement in Sensitivity of Nuclear Magnetic Resonance Spectroscopy for Magnesium Ions in Solution 下载免费PDF全文
Dr. Alexander Gottberg Dr. Monika Stachura Dr. Magdalena Kowalska Dr. Mark L. Bissell Dr. Vaida Arcisauskaite Prof. Klaus Blaum Alexander Helmke Dr. Karl Johnston Dr. Kim Kreim Prof. Flemming H. Larsen Prof. Rainer Neugart Prof. Gerda Neyens Ronald F. Garcia Ruiz Daniel Szunyogh Prof. Peter W. Thulstrup Dr. Deyan T. Yordanov Prof. Lars Hemmingsen 《Chemphyschem》2014,15(18):3929-3932
β‐nuclear magnetic resonance (NMR) spectroscopy is highly sensitive compared to conventional NMR spectroscopy, and may be applied for several elements across the periodic table. β‐NMR has previously been successfully applied in the fields of nuclear and solid‐state physics. In this work, β‐NMR is applied, for the first time, to record an NMR spectrum for a species in solution. 31Mg β‐NMR spectra are measured for as few as 107 magnesium ions in ionic liquid (EMIM‐Ac) within minutes, as a prototypical test case. Resonances are observed at 3882.9 and 3887.2 kHz in an external field of 0.3 T. The key achievement of the current work is to demonstrate that β‐NMR is applicable for the analysis of species in solution, and thus represents a novel spectroscopic technique for use in general chemistry and potentially in biochemistry. 相似文献
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Partial‐Homogeneity‐Based Two‐Dimensional High‐Resolution Nuclear Magnetic Resonance Spectroscopy under Inhomogeneous Magnetic Fields 下载免费PDF全文
Wenqi Qiu Dr. Zhiliang Wei Nan Ding Dr. Yu Yang Qimiao Ye Prof. Yulan Lin Prof. Zhong Chen 《Chemphyschem》2016,17(10):1493-1499
High‐resolution multidimensional nuclear magnetic resonance (NMR) spectroscopy serves as an irreplaceable and versatile tool in various chemical investigations. In this study, a method based on the concept of partial homogeneity is developed to offer two‐dimensional (2D) high‐resolution NMR spectra under inhomogeneous fields. Oscillating gradients are exerted to encode the high‐resolution information, and a field‐inhomogeneity correction algorithm based on pattern recognition is designed to recover high‐resolution spectra. Under fields where inhomogeneity primarily distributes along a single orientation, the proposed method will improve performances of 2D NMR spectroscopy without increasing the experimental duration or significant loss in sensitivity, and thus may open important perspectives for studies of inhomogeneous chemical systems. 相似文献
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核磁共振(NMR)是确定分子结构最常用的分析方法之一,扩散序谱(DOSY)拓展了核磁共振波谱分析复杂混合物的能力。DOSY可以通过测量混合物的自扩散系数,"虚拟分离"多组分系统中的各化学实体。而自扩散系数反映了分子的有效大小和形状,因此DOSY也能提供分子尺寸、分子量、分子间相互作用及聚集状态的具体信息。该文综述了DOSY实验的基本原理、脉冲序列发展及相关研究领域的应用进展。首先简述了脉冲场梯度、脉冲序列的发展及应用特点,然后详细介绍了DOSY在鉴别混合物组分、测量分子尺寸、分子量分布、表征分子间作用力等方面的研究进展。通过实例展示了DOSY在化学、药学、食品、生物等领域的广泛应用。 相似文献
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《Analytical letters》2012,45(3):279-288
Abstract Adequately separated signals in the nuclear megnetic resonance spectra of mixtures of cyclocitrals were assigned to the individual components. This assignment allowed direct integration of the signals of interst and calculation of the percentages of α-cyclocitral, β-cyclocitral, para-cymene, and 1-acetyl-4, 4-dimethyl-1-cyclohexene. The rapidity and nondestructive nature of the nuclear magnetic resonance analysis are superior to the fractional crystallization of the semi-carbazones and gas chromatography techniques previously utilized. 相似文献
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Prof. Xiaobo Qu Dr. Maxim Mayzel Prof. Jian‐Feng Cai Prof. Zhong Chen Prof. Vladislav Orekhov 《Angewandte Chemie (International ed. in English)》2015,54(3):852-854
Accelerated multi‐dimensional NMR spectroscopy is a prerequisite for high‐throughput applications, studying short‐lived molecular systems and monitoring chemical reactions in real time. Non‐uniform sampling is a common approach to reduce the measurement time. Here, a new method for high‐quality spectra reconstruction from non‐uniformly sampled data is introduced, which is based on recent developments in the field of signal processing theory and uses the so far unexploited general property of the NMR signal, its low rank. Using experimental and simulated data, we demonstrate that the low‐rank reconstruction is a viable alternative to the current state‐of‐the‐art technique compressed sensing. In particular, the low‐rank approach is good in preserving of low‐intensity broad peaks, and thus increases the effective sensitivity in the reconstructed spectra. 相似文献