相关实验视频
Updated: Jun 9, 2025

10:26
Fabrication and Characterization of Superconducting Resonators
Published on: May 21, 2016
11.3K
一个用于L频段DNP-NMR的高体积共振器
Adam R Altenhof1, Qing Yang2, Michal Kern2
1MPA-Q, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
Journal of magnetic resonance (San Diego, Calif. : 1997)
|October 23, 2024
概括
一种新的鸟共振器设计使L频段动态核极化核磁共振 (DNP-NMR) 和电子偏磁共振 (EPR) 实验能够获得大样本 (5毫升),克服了以前的限制.
科学领域:
- 磁共振光谱学 磁共振光谱学
- 生物物理化学 生物物理化学
背景情况:
- L频段 (1-2 GHz) DNP-NMR和EPR实验通常仅限于小样本体积 (数百μL).
- 现有的共振器设计,如循环隙和Alderman-Grant线圈,限制了成像和高通量选中的应用.
研究的目的:
- 开发一种能够容纳更大样本体积的新型共振器,用于L频段DNP-NMR和EPR.
- 为了克服当前共振器技术的样本体积限制.
主要方法:
- 一个鸟 (BC) 共振器设计被开发和优化使用模拟.
- 两个相同的BC共振器被堆叠在一起以最大限度地提高样本体积.
- 该设计利用寄生电容,避免固定调电容.
- 使用液态Overhauser-DNP-NMR实验验验证了性能.
主要成果:
- 这种新的BC共振器设计可以容纳几毫升的样品在1.5GHz.
- 在10mM 4-Amino-TEMPO在H2O中的5毫升样本中,获得了-77的增强因子.
- 在100W功率下观察到最小的样本加热 (+3.4K) 持续数秒.
结论:
- 堆叠的鸟共振器设计显著增加了L频段DNP-NMR/EPR的样本体积容量.
- 这一进步促进了DNP-NMR/EPR的更广泛应用,包括成像和高通量查.
- 该设计提供了高效的DNP增强与最小的样品加热.
相关概念视频
NMR Spectrometers: Resolution and Error Correction
675
When magnetic nuclei in a sample achieve resonance and undergo relaxation, the signal detected in NMR is an approximately exponential free induction decay. Fourier transform of an exponential decay yields a Lorentzian peak in the frequency domain. Lorentzian peaks in an NMR spectrum are defined by their amplitude, full width at half maximum, and position, where the peak width is governed by the spin-spin relaxation time alone. In real experiments, however, the applied magnetic field is rendered...
675
Double Resonance Techniques: Overview
191
Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
Spin decoupling is usually achieved by...
191
NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences
766
A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a radio frequency pulse along the x-axis, the nuclei absorb energy corresponding to their Larmor frequencies and achieve resonance. This shifts the net magnetization vector from the z-axis toward the transverse plane. This angle of rotation of the magnetization vector, or the flip angle, is proportional to the duration and intensity of the pulse.
766
NMR Spectrometers: Overview
1.1K
NMR spectrometers consist of a strong magnet, a radiofrequency transmitter, and a detector attached to a computer console for recording spectra of samples containing NMR-active nuclei. In first-generation NMR instruments called continuous-wave spectrometers, the resonance frequencies of the nuclei are determined by frequency-sweep or field-sweep methods. The magnetic field strength is fixed and the rf signal is swept in the former, while the radiofrequency signal is fixed and the magnetic field...
1.1K
Two-Dimensional (2D) NMR: Overview
626
The 1D NMR spectrum of large and complex molecules like natural products has complicated splitting patterns and overlapping signals, which can be easily interpreted using 2-dimensional (2D) NMR. Unlike 1D NMR, 2D NMR has two frequency axes that provide the coupling information between the nucleus A and nucleus B in a molecule. The process from which 2D spectra are obtained has four steps.
The first step is the preparation period, during which nucleus A is excited with a radiofrequency pulse....
The first step is the preparation period, during which nucleus A is excited with a radiofrequency pulse....
626
2D NMR: Overview of Homonuclear Correlation Techniques
173
Homonuclear correlation spectroscopy (COSY) is a powerful technique used in Nuclear Magnetic Resonance (NMR) spectroscopy to study the correlations between nuclei of the same type within a molecule. It provides information about scalar couplings between adjacent nuclei, which helps determine connectivity and structural information. There are several COSY variants, each with its unique strengths and experimental parameters.
COSY90 is the standard two-dimensional (2D) COSY experiment that...
COSY90 is the standard two-dimensional (2D) COSY experiment that...
173

