^(23)Na is a nuclear magnetic resonance(NMR)-active isotope with a nuclear spin quantum number of 3/2.^(23)Na relaxation phenomenon is at the core of ^(23)Na NMR measurement and analysis.Due to the dominance of quadru...^(23)Na is a nuclear magnetic resonance(NMR)-active isotope with a nuclear spin quantum number of 3/2.^(23)Na relaxation phenomenon is at the core of ^(23)Na NMR measurement and analysis.Due to the dominance of quadrupolar interaction,the relaxation behavior of ^(23)Na is physically and mathematically more complex than that of a typical spin-1/2 isotope.In this review,we overview the semi-classical Redfield theory for deriving the formulations of ^(23)Na relaxation.We show that the relaxation behaviors of ^(23)Na can be quantitatively described by constructing the spectral density functions based on the second-order perturbation theory.In addition,we summarize the applications of ^(23)Na relaxometry in different research fields,including biomedicine,sodium ion batteries,and quantum information processing.Because sodium is an essential element in our body,food and industrial materials,the research on sodium by ^(23)Na NMR emerges as important future directions.The theoretical and practical understandings on ^(23)Na relaxation are the step stones for mastering advanced ^(23)Na NMR techniques.展开更多
The samples consisting of 100nm Al or Ag film on optical glass substrate were irradiated by a beam of Xe 5×10<sup>15</sup> to 2×10<sup>16</sup> cm<sup>-2</sup> with energy...The samples consisting of 100nm Al or Ag film on optical glass substrate were irradiated by a beam of Xe 5×10<sup>15</sup> to 2×10<sup>16</sup> cm<sup>-2</sup> with energy 320 keV. The adhesion of films on substrates was tested by Xe<sup>+</sup> irradiation. Optical character was measured by spectrophotometer. The ion mixing amount was measured by RBS. The results showed that after ion irradiating the adhesion of the film on the glass is enhanced. The adherent strength is greater than 10 kg/cm<sup>2</sup>. The thermal stability of the films is good. The irradiated film is more optically efficient, the surface is smooth and rendered more corrosion resistance. The mechanism of the film adhesion was discussed.展开更多
Ion mobility in solid solutions of the fluorite structure 50Pb2–30BiF3–20KF (I) and 50Pb2–30BiF3–20NaF (II) was studied by NMR method. Analysis of 19F, 23Na NMR spectra made it possible to reveal the character of ...Ion mobility in solid solutions of the fluorite structure 50Pb2–30BiF3–20KF (I) and 50Pb2–30BiF3–20NaF (II) was studied by NMR method. Analysis of 19F, 23Na NMR spectra made it possible to reveal the character of ion motions in the fluoride and sodium sublattices with temperature variation, to determine the types and temperature ranges in which they took place. It was found that the dominant form of ionic mobility in the samples I and II above 380 K was the diffusion of fluoride and sodium ions. According to preliminary results of electro-physical studies, the conductivity reached values of ~ 2×10–2 – 10–3 S/cm above 500 K. The solid solutions I and II can be recommended as a basis for use in the development of new functional materials.展开更多
Nb-based tungsten bronze oxides have emerged as attractive materials in various fields,owing to the structural openings and simple synthesis method.In this work,the tetragonal tungsten bronze(TTB)NaWNbO_(6) was prepar...Nb-based tungsten bronze oxides have emerged as attractive materials in various fields,owing to the structural openings and simple synthesis method.In this work,the tetragonal tungsten bronze(TTB)NaWNbO_(6) was prepared by solid state reaction at a relatively low temperature of 775°C.The local structure was systematically studied by solid state nuclear magnetic resonance(SSNMR)with the aid of transition electronic microscopy(TEM).The analysis indicates that NaWNbO6 has pentagonal,square,and triangular tunnels.Notably,square tunnels were partly occupied(50%)by Na,which creates the ability for the Li-ion storage with a volumetric capacity of 210 A·h·L^(−1)at 0.2 C.The 2D ^(23)Na-^(23)Na EXSY results further suggest the ability of ions to fast exchange between the tetragonal and pentagonal tunnels,resulting in a high-rate performance 20 C.展开更多
Changes of sodium ionic concentration of human erythrocytes applied to pulsed electrical field (PEF) were studied by using shift reagent and NMR spectroscopy. The results show that the concentration of intracellular N...Changes of sodium ionic concentration of human erythrocytes applied to pulsed electrical field (PEF) were studied by using shift reagent and NMR spectroscopy. The results show that the concentration of intracellular Na+ increases with the increasing intensity of PEF when the erythrocytes are applied to PEF with higher intensities. The relationship between intracellular Na concentrations and the intensities of PEF does not follow linear or exponen-tial behavior. As the intensities increase, the intracellular Na+ concentrations increase even faster by an exponential curve. However under effects of PEF at lower intensities, intracellular Na+ concentration decreases. Ouabain can in-hibit the decrease of intracellular Na concentration, and the inhibition increases with the increasing concentration of ouabain, suggesting that Na , K -ATPase on cell membrane can be activated by PEF at lower intensities. Direct measurement of activities of the enzyme by using Malachite green method has confirmed this observation. Cell perme-abilities to ions, activation of enzymes by electrical fields and transmission of physical signals like PEF across cell mem-branes are discussed.展开更多
基金National Natural Science Foundation of China 22275159 and 22072133.Leading Innovation and Entrepreneurship Team of Zhejiang Province 2020R01003.
文摘^(23)Na is a nuclear magnetic resonance(NMR)-active isotope with a nuclear spin quantum number of 3/2.^(23)Na relaxation phenomenon is at the core of ^(23)Na NMR measurement and analysis.Due to the dominance of quadrupolar interaction,the relaxation behavior of ^(23)Na is physically and mathematically more complex than that of a typical spin-1/2 isotope.In this review,we overview the semi-classical Redfield theory for deriving the formulations of ^(23)Na relaxation.We show that the relaxation behaviors of ^(23)Na can be quantitatively described by constructing the spectral density functions based on the second-order perturbation theory.In addition,we summarize the applications of ^(23)Na relaxometry in different research fields,including biomedicine,sodium ion batteries,and quantum information processing.Because sodium is an essential element in our body,food and industrial materials,the research on sodium by ^(23)Na NMR emerges as important future directions.The theoretical and practical understandings on ^(23)Na relaxation are the step stones for mastering advanced ^(23)Na NMR techniques.
文摘The samples consisting of 100nm Al or Ag film on optical glass substrate were irradiated by a beam of Xe 5×10<sup>15</sup> to 2×10<sup>16</sup> cm<sup>-2</sup> with energy 320 keV. The adhesion of films on substrates was tested by Xe<sup>+</sup> irradiation. Optical character was measured by spectrophotometer. The ion mixing amount was measured by RBS. The results showed that after ion irradiating the adhesion of the film on the glass is enhanced. The adherent strength is greater than 10 kg/cm<sup>2</sup>. The thermal stability of the films is good. The irradiated film is more optically efficient, the surface is smooth and rendered more corrosion resistance. The mechanism of the film adhesion was discussed.
文摘Ion mobility in solid solutions of the fluorite structure 50Pb2–30BiF3–20KF (I) and 50Pb2–30BiF3–20NaF (II) was studied by NMR method. Analysis of 19F, 23Na NMR spectra made it possible to reveal the character of ion motions in the fluoride and sodium sublattices with temperature variation, to determine the types and temperature ranges in which they took place. It was found that the dominant form of ionic mobility in the samples I and II above 380 K was the diffusion of fluoride and sodium ions. According to preliminary results of electro-physical studies, the conductivity reached values of ~ 2×10–2 – 10–3 S/cm above 500 K. The solid solutions I and II can be recommended as a basis for use in the development of new functional materials.
基金supported by the National Natural Science Foundation of China(Nos.22090043,21622101)the Guangxi Natural Science Foundation,China(No.2019GXNSFGA245006).
文摘Nb-based tungsten bronze oxides have emerged as attractive materials in various fields,owing to the structural openings and simple synthesis method.In this work,the tetragonal tungsten bronze(TTB)NaWNbO_(6) was prepared by solid state reaction at a relatively low temperature of 775°C.The local structure was systematically studied by solid state nuclear magnetic resonance(SSNMR)with the aid of transition electronic microscopy(TEM).The analysis indicates that NaWNbO6 has pentagonal,square,and triangular tunnels.Notably,square tunnels were partly occupied(50%)by Na,which creates the ability for the Li-ion storage with a volumetric capacity of 210 A·h·L^(−1)at 0.2 C.The 2D ^(23)Na-^(23)Na EXSY results further suggest the ability of ions to fast exchange between the tetragonal and pentagonal tunnels,resulting in a high-rate performance 20 C.
基金Project supported by the National Natural Science Foundation of China and the Analytical and Test Center, Beijing.
文摘Changes of sodium ionic concentration of human erythrocytes applied to pulsed electrical field (PEF) were studied by using shift reagent and NMR spectroscopy. The results show that the concentration of intracellular Na+ increases with the increasing intensity of PEF when the erythrocytes are applied to PEF with higher intensities. The relationship between intracellular Na concentrations and the intensities of PEF does not follow linear or exponen-tial behavior. As the intensities increase, the intracellular Na+ concentrations increase even faster by an exponential curve. However under effects of PEF at lower intensities, intracellular Na+ concentration decreases. Ouabain can in-hibit the decrease of intracellular Na concentration, and the inhibition increases with the increasing concentration of ouabain, suggesting that Na , K -ATPase on cell membrane can be activated by PEF at lower intensities. Direct measurement of activities of the enzyme by using Malachite green method has confirmed this observation. Cell perme-abilities to ions, activation of enzymes by electrical fields and transmission of physical signals like PEF across cell mem-branes are discussed.
