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The authors report on a OTDR system using an infrared subpicosecond pulse source in conjunction with balanced heterodyne detection. Experimental results show a sensitivity of more than 100 dB and a resolution of 60 μm in air ...
New radio-frequency pulse envelopes are presented for selective inversion and in-phase excitation in NMR. The envelope functions consist of superpositions of three or four time-shifted Gaussians with optimized widths and peak amplitudes. The offset depende ...
In NMR of spins with I = 1/2 in an isotropic phase, it is demonstrated by simulation and expt. that virtually unlimited bandwidths can be decoupled effectively by using chirp pulses with linear frequency modulation for adiabatic inversion combined with pha ...
In crowded NMR spectra, it is shown how longitudinal relaxation rates (lab.-frame rates 1/T1) can be measured by selective inversion-recovery of a chosen site A followed by selective transfer of magnetization to another site X through a scalar coupling JAX ...
In a study of heteronuclear J NMR spectroscopy, the radio frequency phase of the initial 90 Deg pulse was shifted together with the phase of the refocusing pulse. In heteronuclear spectra, the phase cycling method shifts all resonances by DF1 = (4Dt-1)-1 c ...
By simultaneously irradiating the resonances of 2 selected nuclei in a macromol. with selective radio-frequency fields, one can measure the cross-relaxation rate (Overhauser effect) between 2 sites without perturbations due to spin-diffusion effects involv ...
Collective Thomson scattering, using a high-power pulsed D2O laser at 385-mu-m and a heterodyne receiver system, has provided local ion temperature (T(i)) measurements of the plasma in the tokamak chauffage Alfven (TCA) tokamak. Recent improvements in the ...
New amplitude-modulated radio-frequency pulses are proposed that allow one to achieve selective excitation, de-excitation, inversion, and refocusing of spin-1/2 systems in NMR. The rotation angles and axes are well defined over a chosen bandwidth, regardle ...
Two-dimensional (2D) Fourier transform ion cyclotron resonance (2D FT-ICR) allows one to obtain direct evidence for the occurrence of ion-mol. reactions. In 2D FT-ICR spectra, one observes resonances with 2 distinct frequency coordinates w1 and w2 that cor ...