Miniature solenoids routinely enhance small volume nuclear magnetic resonance imaging and spectroscopy; however, no such techniques exist for patients. We present an implantable microcoil for diverse clinical applications, with a microliter coil volume. The design is loosely based on implantable depth electrodes, in which a flexible tube serves as the substrate, and a metal stylet is inserted into the tube during implantation. The goal is to provide enhanced signal-to-noise ratio (SNR) of structures that are not easily accessed by surface coils. The first-generation prototype was designed for implantation up to 2 cm, and provided initial proof-of-concept for microscopy. Subsequently, we optimized the design to minimize the influence of lead inductances, and to thereby double the length of the implantable depth (4 cm). The second-generation design represents an estimated SNR improvement of over 30% as compared to the original design when extended to 4 cm. Impedance measurements indicate that the device is stable for up to 24 h in body temperature saline. We evaluated the SNR and MR-related heating of the device at 3T. The implantable microcoil can differentiate fat and water peaks, and resolve submillimeter features.

In order to investigate the atomic and electronic structures, pulse NMR experiments were carried out on 27Al in the melt spun Ca100−xAlx metallic glass system and the related crystalline compounds. The spin-echo quadrupole spectra indicate considerable distribution in the electric field gradient and non-uniaxial local symmetry for the Al atoms. Measurem the spin-lattice relaxation time are consistent with a small density of s-electron states at the Al sites as predicted by recent band structure calculations.

Measurements of the spin-lattice relaxation rates in the group-III-V compounds, GaAs, GaSb, InAs, and InSb, are presented as a function of temperature from 4 to 300 K. These rates, except for GaSb, are separated into magnetic and quadrupolar parts. The quadrupolar rates are separated into relaxation by acoustic phonons and that by optical phonons. A simple phenomenological model fits the data to within 5% over the temperature range. The optical phonons couple more strongly to the III nuclei than to the V. This differential coupling is discussed in terms of a dipole mechanism for the electric field gradients.

Measurements of the Knight shift $K$ of ${\mathrm{Cu}}^{63}$ and the nuclear spin-lattice relaxation rate ${{T}_{1}}^{\ensuremath{-}1}$ of ${\mathrm{Cu}}^{63}$ and ${\mathrm{Cu}}^{65}$ are reported for solid and liquid copper. The temperature $T$ range covered for the solid is 300\ifmmode^\circ\else\textdegree\fi{}K to the melting point (1356\ifmmode^\circ\else\textdegree\fi{}K). Measurements of $K$ in the liquid extend from 1200\ifmmode^\circ\else\textdegree\fi{}K (supercooled) to 1450\ifmmode^\circ\else\textdegree\fi{}K; measurements of ${{T}_{1}}^{\ensuremath{-}1}$ cover the range 1200-1370\ifmmode^\circ\else\textdegree\fi{}K. In the solid, the Knight shift shows a slight increase with temperature and, up to about 1000\ifmmode^\circ\else\textdegree\fi{}K, the product ${T}_{1}T{K}^{2}$ is constant. Above 1000\ifmmode^\circ\else\textdegree\fi{}K, an additional contribution to ${{T}_{1}}^{\ensuremath{-}1}$ is observed which is attributed to a quadrupolar interaction with diffusing imperfections. There is a sudden increase of about 3.7% in $K$ and 20% in the inferred magnetic contribution to ${{T}_{1}}^{\ensuremath{-}1}$ on going from the solid to the liquid state at 1356\ifmmode^\circ\else\textdegree\fi{}K. In the liquid state, both $K$ and ${T}_{1}T$ are independent of $T$. The values of ${{T}_{1}}^{\ensuremath{-}1}$ in the liquid are consistent with a lack of quadrupolar contribution to ${{T}_{1}}^{\ensuremath{-}1}$.

The spin–lattice relaxation time T1 of the deuterons in potassium oxalate monohydrate, K2C2O4·D2O, has been measured in the temperature range − 19 to 75°C. T1 decreases with temperature from about 70 sec at − 15°C to 0.02 sec at 75°C. The magnitude of T1 and the strong temperature dependence show that the spin–lattice relaxation is caused by fluctuations of the nuclear quadrupolar interaction resulting from the 180° flip motion of the water molecules in the lattice. The average waiting time between flips, τ, is determined directly at −15°C to be 1.0 ± 0.1 msec. The ratio T1 / τ is found to be (3.8 ± 0.3) × 104, in good agreement with the value calculated from the proposed relaxation mechanism, (4.00 ± 0.05) × 104. From the temperature dependence of T1 the potential barrier hindering the flip motion is found to be 16.3 ± 0.1 kcal/mol. This value is in good agreement with the value calculated earlier from a point-charge model by Pedersen.