Journal of magnetic resonance最新文献_第6页

A mathematical model of NMR transverse relaxation for pore size distribution estimation in porous media 多孔介质中孔径分布估计的核磁共振横向弛豫数学模型

IF 2 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2025-10-01 Epub Date: 2025-06-23 DOI: 10.1016/j.jmr.2025.107922

S. Morales-Chávez , M.A. Valdez-Grijalva , M.A. Díaz-Viera , E. Lucas-Oliveira , T.J. Bonagamba

Nuclear Magnetic Resonance (NMR) is a widely useful technique for studying porous media. Of particular interest are transverse relaxation times (

T_{2}

), which are often associated with pore size when surface relaxation is the dominant mechanism. Under specific physical assumptions, a distribution of

T_{2}

can be used to infer the pore size distribution (PSD). However, in real porous rocks, a combination of diffusion and relaxation mechanisms complicates this interpretation. Despite recent advancements in industrial applications, conventional models frequently rely on simplifying assumptions, particularly when pore size is considered in the fast diffusion regime. This results in the neglect of transverse bulk relaxation (

T_{2 B}

) effects, leading to underestimations of pore sizes. To address this, numerical methods, particularly the Finite Element Method (FEM), offer flexibility in modeling symmetric geometries while significantly reducing computational complexity. This paper presents a mathematical NMR model and numerical implementation based on FEM to simulate transverse magnetization signals for a PSD, validated with semi-analytical solutions and applied to synthetic and real samples, such as Berea sandstone. Additionally, a change of variable in the Inverse Laplace Transform (ILT) model is introduced for the direct PSD estimation, demonstrating a strong agreement between experimental and simulated data.

核磁共振（NMR）是一种广泛应用于多孔介质研究的技术。特别令人感兴趣的是横向弛豫时间（T2），当表面弛豫是主要机制时，它通常与孔径有关。在特定的物理假设下，可以利用T2的分布来推断孔隙尺寸分布（PSD）。然而，在真实的多孔岩石中，扩散和松弛机制的结合使这种解释复杂化。尽管最近在工业应用中取得了进展，但传统模型经常依赖于简化的假设，特别是在考虑快速扩散状态下的孔径时。这导致忽略了横向体松弛（T2B）效应，从而导致孔隙尺寸的低估。为了解决这个问题，数值方法，特别是有限元法（FEM），在对称几何建模方面提供了灵活性，同时显著降低了计算复杂性。本文提出了一个核磁共振数学模型和基于FEM的数值实现，用于模拟PSD的横向磁化信号，并通过半解析解进行了验证，并应用于合成样品和实际样品，如Berea砂岩。此外，引入了拉普拉斯逆变换（ILT）模型中的变量变化来直接估计PSD，证明了实验数据和模拟数据之间的强烈一致性。

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引用次数: 0

Protecting air/moisture-sensitive samples using perdeuterated paraffin wax for solid-state NMR experiments under magic-angle spinning 用渗透石蜡在魔角纺丝下保护对空气/水分敏感的固体核磁共振实验样品

IF 2 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2025-10-01 Epub Date: 2025-07-11 DOI: 10.1016/j.jmr.2025.107935

Emma A. Foley , Joseph F. Thuma , Jacob Mayer , Mita Halder , Wenyu Huang , Frédéric A. Perras , Damien B. Culver , Takeshi Kobayashi

Solid-state nuclear magnetic resonance (SSNMR) spectroscopy is a powerful technique for materials characterization, yet its application to air- and moisture-sensitive materials is often hindered by the difficulty in maintaining an inert environment during magic-angle spinning (MAS). This is particularly true for fast-MAS rotors that do not generally provide tight seals. Herein, we present a generalizable approach employing perdeuterated paraffin waxes—n-icosane-d42 and c-dodecane-d24—as protective embedding media to analyze sensitive organometallic catalysts using SSNMR. We demonstrate that these waxes significantly slow oxidative degradation under MAS conditions. Weak background ¹H and ¹³C NMR signals from the waxes are effectively suppressed using double-quantum filtration and cross-polarization techniques. These findings offer a robust method for expanding the scope of SSNMR to air-sensitive systems, with implications for the structural study of reactive materials and catalysts.

固态核磁共振（SSNMR）光谱是一种强大的材料表征技术，但其在空气和水分敏感材料中的应用往往受到魔角旋转（MAS）过程中难以保持惰性环境的阻碍。对于通常不提供紧密密封的快速mas转子尤其如此。在此，我们提出了一种通用的方法，采用渗透过氘石蜡- n-二十烷-d42和c-十二烷-d24作为保护包埋介质，使用SSNMR分析敏感的有机金属催化剂。我们证明这些蜡在MAS条件下显著减缓氧化降解。采用双量子过滤和交叉极化技术有效地抑制了蜡的弱背景1H和13C核磁共振信号。这些发现为将SSNMR的范围扩展到空气敏感系统提供了一种强大的方法，对反应材料和催化剂的结构研究具有重要意义。

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引用次数: 0

Rapid flow characterization measurements using a modified CPMG measurement with incremented echo times, phase cycling and filtering 快速流动特性测量使用改进的CPMG测量增加回声时间，相位循环和滤波

IF 2 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2025-10-01 Epub Date: 2025-07-18 DOI: 10.1016/j.jmr.2025.107923

Sebastian J. Richard, Benedict Newling, Bruce J. Balcom

We recently demonstrated a magnetic resonance methodology for measuring and characterizing various pipe flows, using a series of individually-acquired spin echoes at different

τ

. The key advantage of our approach lies in the simplicity of the experiment, MR hardware, and data processing. However, acquiring each spin echo separately results in prolonged measurement times. To address this, we employ an echo-train approach to acquire the series of variable

τ

spin echoes. By incrementing CPMG echo pulse spacings within the echo train and implementing a four-step phase cycling scheme to suppress coherence pathway effects, we obtain the same echo phase and magnitude response to flow as a function of

τ^{2}

as in our original method, without requiring individual echo acquisitions. This new approach significantly reduces the number of required experiments, shortening measurement time by a factor of

1 / N

, where

N

is the number of utilized echoes per echo train. Our phase cycling strategy, combined with incremented pulse spacings, enables

N = 3

in our benchtop flow measurement. Validation experiments with Newtonian and shear-thinning fluids confirm that the new echo-train technique yields results consistent with the original approach of acquiring each spin echo separately.

我们最近展示了一种磁共振方法，用于测量和表征各种管道流动，使用不同τ下的一系列单独获得的自旋回波。该方法的主要优势在于实验、MR硬件和数据处理的简单性。然而，单独获取每个自旋回波会导致测量时间延长。为了解决这个问题，我们采用回波序列方法来获取一系列变τ自旋回波。通过在回波序列中增加CPMG回波脉冲间隔，并实施四步相位循环方案来抑制相干路径效应，我们获得了与原始方法相同的回波相位和振幅响应，作为τ2的函数，而不需要单独的回波采集。这种新方法显著减少了所需的实验次数，将测量时间缩短了1/N，其中N为每个回波序列所利用的回波数。我们的相位循环策略，结合增量脉冲间隔，使我们的台式流量测量N=3。牛顿流体和剪切变稀流体的验证实验证实，新的回波序列技术产生的结果与单独获取每个自旋回波的原始方法一致。

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引用次数: 0

Broadband excitation of nuclei spin by refocused feedback 重聚焦反馈对原子核自旋的宽带激发

IF 2 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2025-10-01 Epub Date: 2025-07-16 DOI: 10.1016/j.jmr.2025.107927

Vishesh Kaushik, Navin Khaneja

The ability to precisely control the spin states of nuclei in an ensemble is critical for advancing NMR spectroscopy. In this paper, we present a technique referred to as Refocused Feedback to construct RF pulses that enable uniform transitions of spin states across the continuous spectrum of chemical shifts. It is used to achieve uniform broadband excitation of nuclei ensemble. The RF pulses are designed based on strategically selected hypothetical initial and final conditions, with the pulse phase iteratively updated according to the feedback control law. The control sequence is then transformed for applications in real systems. This approach ensures uniform excitation across the continuous range of chemical shifts while digitally constructing the pulse sequence from discrete samples.

精确控制系综中原子核自旋态的能力对于推进核磁共振波谱学至关重要。在本文中，我们提出了一种称为再聚焦反馈的技术，用于构建射频脉冲，使自旋态能够在化学位移的连续光谱中均匀跃迁。它被用来实现原子核系综的均匀宽带激发。基于策略选择的假设初始和最终条件设计射频脉冲，并根据反馈控制律迭代更新脉冲相位。然后将控制序列转换为实际系统中的应用。这种方法确保在化学位移的连续范围内均匀激发，同时从离散样品中数字化构建脉冲序列。

引用次数: 0

Gradient coil design for a 0.23 T NICU MRI system using an improved two-step Target-Field Method with enhanced linearity and compact design 采用改进的两步靶场法设计0.23 T NICU MRI系统的梯度线圈，增强了线性和紧凑的设计

IF 2 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2025-10-01 Epub Date: 2025-07-24 DOI: 10.1016/j.jmr.2025.107936

Jinhao Liu , Miutian Wang , Wenchen Wang , Yaohui Wang , Weimin Wang , Feng Liu

This study presents an optimized gradient coil design for a miniature 0.23 T MRI system, aimed at improving absolute and relative magnetic field linearity while accommodating various gradient thicknesses. The design uses a two-step optimization approach: the first step uses Tikhonov regularization to solve a linear problem, providing a stable solution, and the second step refines the solution through nonlinear constrained optimization to further enhance field linearity. An explicit objective function for the inductance matrix of biplanar gradient coils is simplified to enhance computational efficiency. Validation through MATLAB and COMSOL finite element analysis showed excellent performance. Imaging experiments were conducted on small animals (cats and dogs, whose sizes are similar to neonates) while awaiting ethical approval for human neonatal studies. Results demonstrated that all gradient coils achieved absolute and relative linearity errors below 5%. Cubic phantom scans showed slight displacement at the edges, but the structured phantom MRI lines align precisely with the physical markers, indicating negligible geometric distortion. The shield design maintained Z-leakage fields below 5 Gauss, with eddy current compensation achieving a 90% reduction (residual X/Y-gradient

<

0.05%, Z-gradient

<

0.20%). T1 and T2-weighted images depicted clear brain structures, while FLAIR and STIR sequences effectively highlighted tissue changes. The proposed gradient coil design method significantly improves absolute and relative linearity while accommodating various gradient thicknesses, demonstrating strong resistance to interference and broad applicability. The comprehensive design-to-manufacturing process ensures optimal parameter selection, resulting in high-quality imaging across multiple MRI sequences. This design demonstrates strong potential for precise in-vivo brain imaging in further NICU applications.

本研究提出了一种优化的梯度线圈设计，用于微型0.23 T MRI系统，旨在提高绝对和相对磁场线性度，同时适应各种梯度厚度。设计采用两步优化方法：第一步采用Tikhonov正则化求解线性问题，提供稳定解，第二步通过非线性约束优化细化解，进一步增强场线性度。为了提高计算效率，对双平面梯度线圈电感矩阵的显式目标函数进行了简化。通过MATLAB和COMSOL有限元分析验证，显示出优异的性能。成像实验是在小动物（猫和狗，它们的大小与新生儿相似）上进行的，同时等待人类新生儿研究的伦理批准。结果表明，所有梯度线圈的绝对线性和相对线性误差均在5%以下。立方体幻象扫描显示边缘有轻微的位移，但结构化的幻象MRI线与物理标记精确对齐，表明几何畸变可以忽略不计。屏蔽设计将z泄漏场保持在5高斯以下，涡流补偿实现了90%的减少(残余X/ y梯度<；0.05%， z梯度<；0.20%)。T1和t2加权图像描绘了清晰的大脑结构，而FLAIR和STIR序列有效地突出了组织变化。所提出的梯度线圈设计方法在适应各种梯度厚度的同时，显著提高了绝对线性度和相对线性度，具有较强的抗干扰性和广泛的适用性。全面的设计到制造过程确保了最佳的参数选择，从而在多个MRI序列中产生高质量的成像。该设计显示了在进一步的新生儿重症监护病房应用中精确的活体脑成像的强大潜力。

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引用次数: 0

Removing magnetic field noise from NMR spectra: Reference deconvolution revisited 从核磁共振波谱中去除磁场噪声：参考反褶积

IF 1.9 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2025-10-01 Epub Date: 2025-07-28 DOI: 10.1016/j.jmr.2025.107937

Alexander Karabanov , Eugeny Kryukov , Gareth Morris , Jeremy Good

Reference deconvolution, a powerful mathematical tool for removing the effects of imperfections of the main magnetic field on NMR spectra, is revisited in the context of strong static and dynamic field perturbations. The theoretical basis and experimental evidence for the high efficiency of reference deconvolution for strong magnetic field distortions in basic liquid-state one- and two-dimensional NMR are given.

In particular, in 2D NMR, we utilise our observation that a strong static inhomogeneity of the main magnetic field suppresses anti-echo coherence transfer contributions, enabling reference deconvolution to be applied to the remaining echo contributions, in each indirect increment separately, in a manner similar to 1D NMR. We show that, in both 1D and 2D NMR, reference deconvolution enables one to remove the vibrational artefacts of cold head operation in cryogen-free magnets.

This extends the applicability of reference deconvolution in multi-dimensional NMR and advances cryogen-free technology in liquid-state NMR.

参考反褶积是一种强大的数学工具，用于消除主磁场缺陷对核磁共振波谱的影响，在强静态和动态场扰动的背景下重新审视。给出了对强磁场畸变进行高效参考反褶积的理论基础和实验证据。特别是，在二维核磁共振中，我们利用我们的观察，即主磁场的强静态不均匀性抑制了反回波相干转移贡献，使得参考反卷积能够以类似于一维核磁共振的方式，在每个间接增量中分别应用于剩余的回波贡献。我们表明，在一维和二维核磁共振中，参考反褶积使人们能够消除无低温磁体中冷头操作的振动伪影。这扩大了参考反褶积在多维核磁共振中的适用性，并推进了液态核磁共振的无低温技术。

引用次数: 0

Diamond rotors for high magic angle spinning frequencies 高魔角旋转频率的金刚石转子

IF 2 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2025-10-01 Epub Date: 2025-05-26 DOI: 10.1016/j.jmr.2025.107909

Lauren Schaffer , David Preiss , Ravi Shankar Palani , Nicholas Wiesner , Jiaming Liu , Samuel Strymish , Salima Bahri , Sara Linse , Neil Gershenfeld , Robert G. Griffin

Magic Angle Spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy is limited in spectral resolution by the spinning frequency of rotors that hold the analyte. Traditional yttria-stabilized zirconia (YSZ) rotors have mechanical constraints that typically limit spinning frequencies of 0.7 mm rotors to ω_r/2π ∼ 110 kHz. These frequencies are not sufficient to achieve resolution comparable to that of solution NMR, which theoretically requires ω_r/2π > 300 kHz. Building upon prior work that utilized rotary-assisted drilling, we present significant advances in diamond rotor fabrication using a high precision lathe and a centerless laser machining fixture that achieves improved concentricity of the rotor outer and inner diameters and spinning stability. The new crop of diamond rotors, which interface with the Bruker MAS 3 spinning system equivalently or better than commercial rotors, were spun using automatic 0.7 mm profiles. Furthermore, diamond rotors can be emptied and repacked, and we describe a set of 3D-printed centrifuge tools for efficient execution of this process. We evaluate chemical vapor deposition (CVD) versus high-pressure high-temperature (HPHT) diamonds as rotor material and find HPHT preferable. Extended spin stability tests and multidimensional NMR spectra of Aβ₁_–₄₀ demonstrate the robustness and usability of these rotors. These advances pave the way for higher frequency spinning with helium gas in the future, enabling transformative improvements in MAS NMR for biological and material sciences.

魔角旋转（MAS）核磁共振（NMR）光谱学的光谱分辨率受到固定分析物的转子旋转频率的限制。传统的钇稳定氧化锆（YSZ）转子具有机械限制，通常将0.7 mm转子的旋转频率限制在ωr/2π ~ 110 kHz。这些频率不足以达到与溶液核磁共振相当的分辨率，理论上需要ωr/2π >；300千赫。在先前利用旋转辅助钻孔的工作基础上，我们提出了金刚石转子制造的重大进展，使用高精度车床和无心激光加工夹具，实现了转子外径和内径的同心度和旋转稳定性的改善。新一代金刚石转子与布鲁克MAS 3纺丝系统的接口相当于或优于商用转子，使用0.7毫米的自动轮廓进行纺丝。此外，钻石转子可以清空和重新包装，我们描述了一套3d打印离心机工具，用于有效执行这一过程。我们评估了化学气相沉积（CVD）和高压高温（HPHT）钻石作为转子材料，发现高压高温（HPHT）更可取。扩展的自旋稳定性测试和Aβ1-40的多维核磁共振谱证明了这些转子的鲁棒性和可用性。这些进步为未来用氦气进行更高频率旋转铺平了道路，使生物和材料科学的MAS NMR实现了变革性改进。

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引用次数: 0

Design and characterization of a tunable open TE011 resonator for Q-band pulse EPR experiments 用于q波段脉冲EPR实验的可调谐开放式TE011谐振腔的设计与表征

IF 2 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2025-09-01 Epub Date: 2025-06-08 DOI: 10.1016/j.jmr.2025.107921

Kyle Jorgensen, Alexey Silakov

Electron Paramagnetic Resonance (EPR) is an important technique for the investigation of the structure and function of metalloproteins and enzymes. The variety of questions in this line of research requires versatile instrumentation. In this work, we explored the utility of the open resonator concept for a general-use highly tunable TE₀₁₁ resonator design at Q-band frequencies (≈ 34 GHz). Using proof-of-concept calculations, we establish a viable range of critical parameters compatible with the desired instrument specifications. We then present the resonator design, targeting ease of execution and handling. Experimental characterization of the built resonator shows high tunability. Specifically, we show that the resonator can be critically coupled and overcoupled with a three-fold change in the bandwidth using a matching short. We also show that the resonator can be incorporated with frequency tuning by means of movable axial plungers, allowing it to work with a wide range of samples using relatively narrow-bandwidth microwave instrumentation. Furthermore, because of its high tunability, the resonator is very tolerant of manufacturing imperfections, which makes it affordable and easy to execute with minimal tooling. We also discuss the long-term use of the resonator in our research, highlighting its versatility.

电子顺磁共振（EPR）是研究金属蛋白和酶的结构和功能的重要技术。这条研究路线中各种各样的问题需要多种多样的仪器。在这项工作中，我们探索了开放谐振器概念在q波段（≈34 GHz）通用高可调谐TE011谐振器设计中的实用性。使用概念验证计算，我们建立了与所需仪器规格兼容的可行关键参数范围。然后，我们提出了谐振器的设计，目标是易于执行和处理。实验结果表明，该谐振器具有较高的可调性。具体地说，我们证明了谐振器可以在使用匹配短路的带宽变化三倍的情况下进行临界耦合和过耦合。我们还表明，谐振器可以通过可移动的轴向柱塞与频率调谐相结合，使其能够使用相对窄带宽的微波仪器处理大范围的样品。此外，由于其高可调性，谐振器对制造缺陷的容忍度非常高，这使得它价格合理，并且易于使用最少的工具执行。我们还在研究中讨论了谐振器的长期使用，突出了它的多功能性。

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引用次数: 0

Circuit design for broadband decoupling in multi-coil multi-nuclear applications 多线圈多核应用中宽带去耦电路设计

IF 2 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2025-09-01 Epub Date: 2025-06-18 DOI: 10.1016/j.jmr.2025.107924

Joseph Busher , Edith Touchet-Valle , Jacob Degitz , Mary P. McDougall

The wealth of information available from multinuclear magnetic resonance imaging and spectroscopy is largely untapped in the clinical setting. This is due to a multitude of challenges in the pipeline ranging from acquisition strategies, hardware design, processing, and interpretation/analysis. As a small part of addressing these challenges, this work presents a straightforward approach for broadband decoupling between coils. This circuit was created with the implementation of a series PIN diode and was evaluated on the bench and experimentally for ¹H, ³¹P and ²³Na at 3 T. Individual coils were single-tuned with this decoupling network and stacked to enable a switched triple-tuned coil. These coils were evaluated in various purposefully coupled configurations and compared to a narrowband trap active detuning network to demonstrate potential modularity of this design. Narrowband trapped coils showed drops in SNR when combined with other coils, presumably due to coupling between receiver elements tuned to different frequencies. This broadband decoupling behavior was shown to be independent of positioning through coils oriented to be nearly perfectly geometrically coupled and the addition of a three-element array of the same size. This configuration was validated on a post-mortem pig to verify the losses of the network did not prohibit its use for preclinical imaging and spectroscopy applications. Although losses were incurred as a result of the broadband decoupling network, it enabled a modular design that can be adapted to a given study without significant compromise of the signal integrity and could eliminate the need for certain custom coils for multi-nuclear studies.

从多核磁共振成像和光谱学中获得的丰富信息在临床环境中很大程度上尚未得到开发。这是由于在获取策略、硬件设计、处理和解释/分析等方面存在大量挑战。作为解决这些挑战的一小部分，这项工作提出了一种直接的线圈间宽带解耦方法。该电路是通过实现串联PIN二极管创建的，并在3t下对1H， 31P和23Na进行了台架和实验评估，单个线圈使用该去耦网络进行单调谐，并堆叠以启用开关三调谐线圈。这些线圈在各种有目的的耦合配置下进行了评估，并与窄带陷阱有源失谐网络进行了比较，以证明该设计的潜在模块化。窄带捕获线圈与其他线圈组合时显示信噪比下降，可能是由于调谐到不同频率的接收器元件之间的耦合。这种宽带去耦行为被证明与定位无关，通过线圈定向成几乎完美的几何耦合和添加相同尺寸的三元阵列。该配置在死后的猪身上进行了验证，以验证网络的损失不会阻止其用于临床前成像和光谱应用。尽管宽带解耦网络造成了损耗，但它实现了模块化设计，可以适应给定的研究，而不会显著损害信号完整性，并且可以消除对多核研究中某些定制线圈的需求。

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引用次数: 0

Probe design for high sensitivity proton-detected solid-state NMR 高灵敏度质子探测固态核磁共振探针设计

IF 2 3区化学 Q3 BIOCHEMICAL RESEARCH METHODS

Journal of magnetic resonance

Pub Date : 2025-09-01 Epub Date: 2025-06-09 DOI: 10.1016/j.jmr.2025.107919

Collin G. Borcik , Lauren E. Price , John P. Heinrich , John A. Stringer , Chad M. Rienstra

Proton (¹H) detection methodologies in solid-state NMR (SSNMR) have revolutionized the field allowing for probing of new frontiers in determining the structure and dynamics within biological systems and materials. While approaches that maximally leverage the high gyromagnetic ratio of ¹H detection have enhanced sensitivity and resolution of SSNMR experiments, the radiofrequency (rf) circuit of magic-angle spinning (MAS) probes is not well optimized for ¹H detection, limiting the overall signal-to-noise ratio (SNR). Rather, SSNMR probes have historically been optimized for lower gamma nuclei such as ¹³C and below. Here we present a design with an inner coil for proton (¹H) to maximize ¹H sensitivity. Optimizing the ¹H channel resulted in a 1.33–2-fold increase in SNR with ¹H detection in a one-dimensional experiment. An outer coil is tuned to the ¹³C and ¹⁵N frequencies, with excellent B₁ homogeneity on all three channels. Using this design, we find that the sensitivity scales better than the theoretical expectations from 600 MHz to 750 MHz, due to a combination of the improved rf efficiency and B₁ homogeneity. We also demonstrate these improvements on a model protein system (GB1) with a 4D experiment collected in less than a day.

固态核磁共振（SSNMR）中的质子（1H）检测方法已经彻底改变了该领域，允许在确定生物系统和材料的结构和动力学方面探索新的前沿。虽然最大限度地利用1H检测的高回旋磁比的方法提高了SSNMR实验的灵敏度和分辨率，但魔角旋转（MAS）探头的射频（rf）电路并未很好地优化用于1H检测，限制了整体信噪比（SNR）。相反，ssmr探测器历来针对低γ核（如13C及以下）进行了优化。在这里，我们提出了一个内部线圈的质子（1H）的设计，以最大限度地提高1H的灵敏度。在一维实验中，优化1H通道使1H检测的信噪比提高1.33 - 2倍。外线圈调谐到13C和15N频率，在所有三个频道上都具有出色的B1均匀性。使用这种设计，我们发现在600 MHz到750 MHz范围内，由于改进的射频效率和B1均匀性的结合，灵敏度的尺度优于理论预期。我们还在不到一天的时间内收集了4D实验，在模型蛋白质系统（GB1）上展示了这些改进。

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引用次数: 0