Jove
Visualize
联系我们
JoVE
x logofacebook logolinkedin logoyoutube logo
关于 JoVE
概览领导团队博客JoVE 帮助中心
作者
出版流程编辑委员会范围与政策同行评审常见问题投稿
图书馆员
用户评价订阅访问资源图书馆顾问委员会常见问题
研究
JoVE JournalMethods CollectionsJoVE Encyclopedia of Experiments存档
教育
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab Manual教师资源中心教师网站
使用条款与条件
隐私政策
政策

相关概念视频

Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule01:10

Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule

2.4K
In the AX proton spin system, proton A can sense the two spin states of a coupled proton X, resulting in a doublet NMR signal with two peaks of equal (1:1) intensity. When proton A is coupled to two equivalent protons (AX2 spin system), the spin states of each X can be aligned with or against the external field, creating three possible scenarios. This results in a 1:2:1  triplet signal, where the central peak corresponds to the chemical shift of A and is twice as large or intense as the...
2.4K
Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)01:20

Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)

1.6K
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
1.6K
¹H NMR Signal Multiplicity: Splitting Patterns01:13

¹H NMR Signal Multiplicity: Splitting Patterns

6.5K
When protons A and X are coupled, their nuclear spin energy levels are slightly modified. This is because the energy required to excite proton A to a spin state parallel to proton X is slightly different from the energy required for it to become anti-parallel to spin X. Consequently, there are two possible excitation frequencies for A (A1 and A2), depending on the spin state of X, and vice versa. The mutual nature of coupling implies that the difference between frequencies A1 and A2, indicated...
6.5K
¹³C NMR: ¹H–¹³C Decoupling01:04

¹³C NMR: ¹H–¹³C Decoupling

1.7K
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
1.7K
¹H NMR: Complex Splitting01:13

¹H NMR: Complex Splitting

1.8K
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
1.8K

您也可能阅读

相关文章

通过共同作者、期刊和引用图与本文相关的文章。

排序
Same author

hexABC seeking the physical code of DNA.

Nature communications·2026
Same author

Rapid estimation of protein folding pathways from sequence alone using AlphaFold2.

Nature communications·2025
Same author

AlphaFold2 <i>knows</i> some protein folding principles.

bioRxiv : the preprint server for biology·2024
Same author

Revolutionizing Peptide-Based Drug Discovery: Advances in the Post-AlphaFold Era.

Wiley interdisciplinary reviews. Computational molecular science·2024
Same author

Modelling peptide-protein complexes: docking, simulations and machine learning.

QRB discovery·2023
Same author

Engineering highly thermostable Cas12b via de novo structural analyses for one-pot detection of nucleic acids.

Cell reports. Medicine·2023
Same journal

Denoising algorithm of Φ-OTDR systems based on adaptive fractional wavelet transform denoising.

Optics express·2026
Same journal

Millisecond photon-to-photon latency and high-speed volumetric projection system for optogenetics.

Optics express·2026
Same journal

Polarization-encoded coaxial structured light for high-precision 3D surface profilometry.

Optics express·2026
Same journal

Discrete freeform optical design based on collaborative optimization of point cloud and local normals.

Optics express·2026
Same journal

Ultrafast ghost imaging with 25 GHz speckle switching and wavelength-division multiplexing.

Optics express·2026
Same journal

Atomic vapor cells fabricated by femtosecond laser welding of standard-optical-quality glass.

Optics express·2026
查看所有相关文章

相关实验视频

Updated: Jan 11, 2026

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
07:56

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference

Published on: September 5, 2019

8.9K

通过共享纠源和被动光束分割器实现多用户连续可变量子密钥分布.

Pu Wang, Zengliang Bai, Liwei Chang

    Optics express
    |November 11, 2025
    PubMed
    概括
    此摘要是机器生成的。

    本研究介绍了一种使用共享纠源的连续变量量子被动光学网络 (CV-QPON). 新协议显著提高了秘密密钥速率和网络可扩展性,用于量子互联网开发.

    更多相关视频

    Generation and Coherent Control of Pulsed Quantum Frequency Combs
    06:42

    Generation and Coherent Control of Pulsed Quantum Frequency Combs

    Published on: June 8, 2018

    9.6K
    Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators
    09:23

    Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

    Published on: May 30, 2014

    15.0K

    相关实验视频

    Last Updated: Jan 11, 2026

    A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
    07:56

    A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference

    Published on: September 5, 2019

    8.9K
    Generation and Coherent Control of Pulsed Quantum Frequency Combs
    06:42

    Generation and Coherent Control of Pulsed Quantum Frequency Combs

    Published on: June 8, 2018

    9.6K
    Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators
    09:23

    Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

    Published on: May 30, 2014

    15.0K

    科学领域:

    • 量子通信是一种量子通信.
    • 量子网络是一个量子网络.
    • 信息安全 信息安全

    背景情况:

    • 开发一个高速率,具有成本效益和安全的量子通信网络对于量子互联网至关重要.
    • 将一个共享的纠源放置在一个中心节点上,可以在星形网络中高效地利用量子资源.

    研究的目的:

    • 提出使用共享纠源的连续变量量子被动光学网络 (CV-QPON).
    • 在不同的源特性场景下评估CV-QPON的安全性和性能.

    主要方法:

    • 实现一个具有共享纠源的连续变量量子被动光学网络 (CV-QPON).
    • 使用完全和部分特征混合纠状态进行安全评估.
    • 应用一个有偏见的基础方案来提高协议性能.

    主要成果:

    • 更新后的协议在秘密密钥速率,传输距离,用户容量和噪声耐受性方面优于以前的方法.
    • 一个7 dB的挤压纠源可以支持256个用户超过50公里与一个完全特征源.
    • 有了部分特征源,一个7dB的挤压源支持64个用户超过30公里,和128个用户超过10公里.

    结论:

    • 拟议的CV-QPON方案为低成本,高速率,安全和大规模的量子网络提供了一个实际的途径.
    • 在部分特征的场景中,放松中央节点的安全假设对于下游CV-QPON系统至关重要.
    • 综合纠源的进步使得这个方案成为未来量子通信网络的有希望的方法.