We demonstrate the possibility to use UDEFT (Uniform Driven Equilibrium Fourier Transform) technique in order to improve the sensitivity and the quantification of one-dimensional ²⁹Si NMR experiments under magic-angle spinning (MAS). We derive an analytical expression of the signal-to-noise ratios of UDEFT and single-pulse (SP) experiments subsuming the contributions of transient and steady-state regimes. Using numerical spin dynamics simulations and experiments on ²⁹Si-enriched amorphous silica and borosilicate glass, we show that 59₁₈₀298₀59₁₈₀ refocusing composite π-pulse and the adiabatic inversion using tanh/tan modulation improve the robustness of UDEFT technique to rf-inhomogeneity, offset, and chemical shift anisotropy. These pulses combined with a two-step phase cycle limit the pulse imperfections and the artifacts produced by stimulated echoes. The sensitivity of SP, UDEFT and CPMG (Carr-Purcell-Meiboom-Gill) techniques are experimentally compared on functionalized and non-functionalized mesoporous silica. Furthermore, experiments on a flame retardant material prove that UDEFT technique provides a better quantification of ²⁹Si sites with higher sensitivity than SP method.

我们证明了使用UDEFT（均匀驱动平衡傅立叶变换）技术的可能性，以提高灵敏角旋转（MAS）下一维²⁹ Si NMR实验的灵敏度和定量。我们推导了UDEFT和单脉冲（SP）实验的信噪比的分析表达式，其中包含了瞬态和稳态机制的贡献。使用数值自旋动力学模拟和²⁹种富硅非晶硅和硼硅酸盐玻璃的实验，我们得出59 ₁₈₀ 298 ₀ 59 ₁₈₀复合π脉冲的重新聚焦以及使用tanh / tan调制的绝热反演提高了UDEFT技术对rf不均匀性，偏移和化学位移各向异性的鲁棒性。这些脉冲与两步相位周期相结合，限制了脉冲缺陷和受激回波产生的伪像。SP，UDEFT和CPMG（Carr-Purcell-Meiboom-Gill）技术的灵敏度在功能化和非功能化介孔二氧化硅上进行了实验比较。此外，在阻燃材料上进行的实验证明，与SP方法相比，UDEFT技术可以更好地量化^29个Si位，灵敏度更高。