Günne, Jörn Schmedt auf der
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Günne, Jörn Schmedt auf der
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Publication Access status: Metadata only , Cement hydration kinetics followed by electron spin resonanceCement hydration is driven by a complex system of chemical reactions of several hydraulic binders and water that influence each other. Here we establish a method to measure the hydration kinetics of an individual clinker phase by electron spin resonance spectroscopy. The hydration of a Mn(II) doped crystalline phase can be analyzed from the decay of signals coming from the starting material and the formed product. Transformation times can be determined by modeling the time series of the signal intensities. The host of the dopant could be identified by combining evidence from different analytical techniques including diffraction and electron microscopy. The results about the reaction kinetics are compared to those obtained from caloric measurements. The method opens a way to study the hydration of different hydraulic binders in complex systems selectively, which includes the determination of induction periods and transformation times from in-situ measurements.Source Type:Article1 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Combining NMR and impedance spectroscopy <i>in situ</i> to study the dynamics of solid ion conductorsUnwanted differences in the apparent ion mobilities as seen by NMR and impedance spectroscopy are removed by a setup that allows measuring both on the same, by which in situ studies of interface stability and phase transitions become possible.Source Type:Article2 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Echo pulses for background suppression by optimal controlMaterials used to construct magic‐angle‐spinning NMR probes can contain NMR active nuclei that produce a significant amount of background signal. Because these materials are located outside the sample coil, the use of spatially selective pulses to remove the background is a popular approach for background suppression. However, previously suggested spatially selective pulses suffer from limited excitation bandwidths, which may make them unsuitable for the acquisition of nuclei with a large chemical shift range. Here, a pulse (OC‐BACK) is presented, which has been developed by optimal control, which has a flat profile of ~120 kHz with respect to off‐resonance effects and extended pass and suppression bands with respect to the nominal nutation frequency. The presented solution is large enough to be effective for background suppression schemes in 19 F magic‐angle‐spinning NMR at medium and low magnetic fields.Source Type:ArticleDOI:10.1002/mrc.53541 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Influence of Mg on the Li ion mobility in Li<sub>4−2<i>x</i></sub>Mg<sub><i>x</i></sub>P<sub>2</sub>S<sub>6</sub>Mg as a roadblock for Li ion motion was investigated by NMR, impedance spectroscopy, quantum-chemical simulations and X-ray diffraction. Aliovalent substitution can cause substantial structural changes in solid ion conductors.Source Type:Article1