Analytical Instrument Documents

CT only undergoes second-order quadrupolar perturbation and the signal is distributed over a narrower range than ST. ST signals are broad, have lower sensitivity, and often exhibit more complex patterns. Therefore, in the case of half-integer quadrupolar nuclei, CT signals are mostly observed and analyzed.

In solid-state NMR, interactions such as dipolar couplings and chemical shift anisotropy often result in extremely broad and low-sensitivity spectra in the stationary state. To address this issue, the sample is tilted at an angle of 54.74 degrees relative to the magnetic field and spun rapidly, creating a state similar to that of a solution. This technique, called MAS (Magic Angle Spinning), improves both resolution and sensitivity.

This Solid-state battery Note has been created to provide solutions and reference information for research and development of solid-state batteries evolving from the lithium ion batteries (LIBs).

Chenometrics is a discipline that utilizes data mining techniques, including dimensionality reduction, discrimination, visualization, and regression, to extract information from extensive sets of experimental analytical data. NMR spectroscopy, a highly quantitative and reproducible technique, allows for non-invasive analysis of chemical species with minimal sample preparation. This is particularly advantageous for data mining, as NMR spectra, including series of 1H NMR spectra of biological samples, are commonly employed as input for multivariate analysis by converting series of 1D NMR spectra into a matrix. The 'Chemospec' package in the R language for statistical computing serves as the engine for multivariate analysis. When the 'Chempspec' package is installed, the Delta software offers a seamless user interface for exploratory multivariate analysis.

Pulsed-Field Gradient Nuclear Magnetic Resonance (PFG-NMR) is utilized to analyze the self-diffusion of molecules and ions. The self-diffusion coefficient (D) in PFG-NMR is determined by recording the decay of signal intensity through a series of experiments using either Pulsed Gradient Spin Echo (PGSE) or Pulsed Gradient Stimulated Echo (PGSTE) sequences with varying gradient strengths (G). The decay of signal intensity is subsequently analyzed using curve fitting or inverse Laplace transformation methods. The Delta NMR software provides a curve analysis tool that supports the fitting of PFG-NMR data. Versions 5.3.3 and earlier of the Delta NMR software support curve fitting using a model that assumes a single self-diffusion coefficient contributing to the decay. However, starting from the Delta NMR software version 6.0 and onwards, there is support for curve fitting using the "Diffusion Analysis Multi" feature. This feature enables the analysis to account for multiple self-diffusion coefficients during the curve fitting process.

Pulsed-Field Gradient NMR (PFG-NMR) is utilized for analyzing the self-diffusion of molecules and ions, which are commonly referred to as 'particles' in this context. The translation of particles by thermal convection significantly impacts the decay curve in PFG-NMR experiments, particularly when dealing with solution and liquid samples. In cases where the convection-induced translation is substantial, the decay curve exhibits a cosine-like behavior, leading to an apparent increase in the self-diffusion coefficient compared to the actual value. Additionally, the decay curves may become distorted, occasionally resulting in the appearance of signals in negative phase. To address this convection artifact in PFG-NMR, Double Stimulated Echo (DSTE) experiments are specifically designed and employed.

A standard NMR system has one high-frequency channel and a low-frequency one, the ECZL series has a new function called the Multi Frequency Drive System.

Structural analysis by NMR can provide not only a planar molecular structure but also three-dimensional structural information. In this Note, we describe a method for obtaining information on dihedral angles by using 1H-1H coupling constants (JHH values). For example, hydrogen atoms attached to a cyclohexane ring are either located in axial or equatorial positions in respect to the cyclohexane ring (Fig. 1). The dihedral angles between vicinal protons are known to be ∠Hax-C-C-Hax ≈ 180°, ∠Hax-C-Heq ≈ 60°, and ∠Heq-C-C-Heq ≈ 60°. If we look at the Karplus curve shown in Fig. 2, we can see that 3JHH of around 4 Hz can be expected in the case of the dihedral angle of 60°, while 3JHH of around 13 Hz corresponds to the dihedral angle of 180°. In reality, 3JHH values depend on substituents attached to the cyclohexane ring in substituted cyclohexanes, so the analysis is not straightforward, but the basic trend of having a larger J-value for a 180° dihedral angle compared to a 60° dihedral angle remains unchanged. Therefore, from the value of 3JHH of the methylene protons, it is possible to differentiate between the dihedral angle of 60° or 180°.

The new generation diffusion probe is specially designed for diffusion applications that requires a large magnetic field gradient. By improving the design around the coil, the recovery time after field gradient pulse has been significantly shortened compared to the conventional model. Using a newly developed 50A bipolar magnetic field gradient power supply, a magnetic field gradient of 20 T/m (2000 G/cm) can be applied, making it possible to measure diffusion coefficients on the order of 10-14 m2/s. This system is ideal for measuring the diffusion of ions in solid electrolytes.

The applications for lithium ion batteries (LIB) cover a wide range, from power sources for personal computers and mobile devices to automobiles, and there is always a demand for even better performance and safety. In order to ensure the performance and quality of LIB, analysis and evaluation using high-performance assessment systems is necessary. JEOL offers a full line-up of equipment to support the development of new LIB technologies and to improve product quality, including instruments for morphology observation and surface analysis, chemical analysis systems to perform structural analysis on a molecular level, as well as fabrication systems to create high-performance coatings and powders. This LIB note offers solutions for researchers and engineers who are looking for the best equipment for their application.