PMC

Influence of the coaxial cable length on the signal. With an increase in the length, the signal gradually becomes slower and the amplitude decreases, but the influence is small.

Circuit schematic for the coil element and preamplifier chain. The coil element uses three capacitors: The variable capacitor C₁ fine-tunes the coil element frequency. Where C₂ and C₃ are equally valued they provide a capacitive voltage divider at the coil output circuit. A detuning trap is formed around C₂ using a variable inductor L and a Diode D. A small coaxial cable connects coil and preamp transforming the element impedance to Z_NM, the noise matched impedance for the preamplifier input. The coaxial cable also transforms the input impedance of the preamplifier to a short across D.

The implanted part is indicated in red. The coil element uses two capacitors: a matching capacitor C₁ and a variable tuning capacitor C₂ that fine-tunes the resonance frequency. A detuning trap is formed around C₁ using a hand-wound inductor L and a Diode D. A small coaxial cable, indicated in blue, connects coil and preamp transforming the element impedance to Z_NM, the noise matched impedance for the preamplifier input. The coaxial cable also transforms the input impedance of the preamplifier to a short across D.

a Schematic figure showing the synthesis of CNT@Si@C microspheres. b A typical SEM image of CNT@SiO₂ microspheres (scale bar = 5 µm). c A representative TEM image of a CNT@SiO₂ core-shell coaxial cable (scale bar = 5 µm). d A STEM image of the CNT@SiO₂ cables (scale bar = 20 µm). e EDS line scan of the CNT@SiO₂ cable marked in d. Small discrepancy of Si and O due to beam effect from prolonged scanning. f A typical SEM image of CNT@Si@C microspheres (scale bar = 3 µm). g Low-magnification TEM image of a composite cable from a CNT@Si@C microsphere (scale bar = 20 µm), h HRTEM image of the cable in g (scale bar = 5 µm). i EDS mapping of the marked area in g (scale bar = 50 µm).