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Mobilizing magnetic resonance
From iPods to space probes, technological progress is driven by the mantra “smaller, faster and cheaper”. Yet for the past few decades one of the best known techniques in physics – nuclear magnetic resonance (NMR) spectroscopy – has followed a different principle: bigger is better. In order to detect the tiny magnetic moments of nuclei, …
Diffusion of Water and Electrolytes in Mesoporous Silica with a Wide Range of Pore Sizes.
The diffusion of alkaline chlorides (LiCl, KCl, and CsCl) and water in mesoporous silica samples with pore sizes covering the range from micropores (2 nm) up to mesopores larger than 30 nm have been measured by resorting to a simple diffusional technique in the case of electrolytes and 1H NMR in the case of water. The …
Spatially Resolved Monitoring of Drying of Hierarchical Porous Organic Networks
Evaporation kinetics of water confined in hierarchal polymeric porous media is studied by low field nuclear magnetic resonance (NMR). Systems synthesized with various degrees of cross-linker density render networks with similar pore sizes but different response when soaked with water. Polymeric networks with low percentage of cross-linker can undergo swelling, which affects the porosity as …
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Ex Situ NMR Relaxometry of Metal-Organic Frameworks for Rapid Surface-Area Screening
Taking a relaxed approach : The NMR relaxation behavior of imbibed solvent has been used to estimate the surface area of a variety of microporous metal–organic frameworks and zeolites. This NMR technique is amenable to automation and can expedite the characterization of microporous materials by identifying any nonporous or low‐surface‐area structures. Chen, Joseph J., et al. …
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Molecular exchange ofn-hexane in zeolite sieves studied by diffusion–diffusion and T1-diffusion nuclear magnetic resonance exchange spectroscopy
Molecular exchange properties and diffusion of n-hexane embedded in a bimodal pore structure with characteristic length scales in the order of nano and micrometres, respectively, formed by packing of zeolite particles, are studied. Two-dimensional (2D) nuclear magnetic resonance (NMR) diffusion correlation experiments together with relaxation–diffusion correlation experiments are performed at low magnetic field using a single-sided …
Quantitative NMR monitoring of liquid ingress into repellent heterogeneous layered fabrics
Fabrics which are water repellent and repellent to other liquids are often constructed using multiple layers of material. Such a construction is preferable to a single layer of a liquid-repellent textile because, under the action of an applied pressure, ingress of a liquid through the first layer can be halted by the second or subsequent …
Magnetic Resonance in Porous Media: Recent Progress
Recent years have seen significant progress in the NMR study of porous media from natural and industrial sources and of cultural significance such as paintings. This paper provides a brief outline of the recent technical development of NMR in this area. These advances are relevant for broad NMR applications in material characterization. Song, Yi-Qiao, et al. “Magnetic Resonance in Porous Media: Recent Progress.” The …
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