2020年5月4日 · Knowing typical 13 C T 1 values is thus key to parameter optimization. 13 C T 1 measurements were taken on three molecules: S-carvone, cis-2-methoxycinnamic acid, and (-)-alpha-thujone. The pulse program t1irig was chosen so 1 H decoupling during acquisition would be performed, but NOE during the relaxation delay would be absent.

2018年12月1日 · In this paper, we present two improved methods for the measurement of 13 C NMR relaxation values in solids with fast local dynamics, such as hydrated elastin. The experiment is improved with a ssNOE/DP pulse sequence module that yields single-exponential decays in 13 C T1 and T1ρ relaxation curves that are determined in shorter experimental runs.

2017年1月9日 · 各个13C核的T1是不同的。 为了实现定量，必须使t时间足够长，保证各个13C核都恢复到1。一般来说，t等于3-5倍的T1(max)时，磁化恢复超过0.95，对各个核来说就可以定量了。这里的T1(max)是各个13C核中，T1最大者。因此，定量13C谱是要测量13C T1的，序列大概 …

A simple pulse sequence that combines a progressive saturation experiment with gate decoupling is proposed for measuring T1 and η values. The calculated η values are a good approximation even for short equilibration delays without any restrictive assumptions about relaxation times of the nuclei involved.

The spectra can be processed by the automation program proc_t1 or manually entering xf2. In all cases, set SI1 as a power of two greater than or equal to the number of delays in vdlist ( SI1=16 ). A linebroadening is usually applied ( lb=2 Hz ).

1999年2月11日 · In this article, we verified the structure of PHEMA and PHEMA-IPN by 13 C CP/MAS NMR. Also, the 13 C spin-lattice relaxation times in the rotating frame, T 1ρ, were measured as a function of temperature. From these results, the mobility, correlation time, and the activation energy for each carbon in the respective PHEMA and PHEMA-IPN were ...

The mechanisms of spin—lattice relaxation of 13C are discussed in the light of T1 data for a number of small molecules. Contributions from dipolar interactions, spin—rotation, chemical shift anisotropy and scalar coupling interactions have been …

T1 values of 13C nuclei are significantly longer than 1H ( at least twice as long). With the common pulse sequence parameter settings, 13C integration quantitation is difficult because the long T1, off-resonance excitation effect due to the large bandwidth, and 1H->13C NOE that contributes differently to the 13C signals.

2018年5月17日 · A robust and selective late-stage deuteration methodology was applied to 13C-enriched amino and alpha hydroxy acids to increase spin-lattice relaxation constant T1 for hyperpolarized 13C magnetic resonance imaging.

A robust and selective late-stage deuteration methodology was applied to 13 C-enriched amino and alpha hydroxy acids to increase spin–lattice relaxation constant T1 for hyperpolarized 13 C magnetic resonance imaging.