Coaxial cable, rigid

Fig. 12.4. Single-tube STM. The tube piezo scanner is adhered inside a sturdy metal cylinder, which sits on three screws on the base plate. The two front screws make the coarse approaching. The rear screw makes fine approaching by using the two front screws as the pivot axis. The rear screw is actuated by a stepping motor for automatic approaching. The preamplifier (not shown) is mounted directly on top of the metal cylinder to eliminate the microphone effect of the coaxial cable between the tip and the input of the preamplifier. The entire unit is rigid enough that a mediocre vibration isolation device can provide atomic resolution. (After Hansma et al., 1988.)...

The different parts of a flame detector must be rigid. If bumping the gas chromatograph moves the collector momentarily by 0.1 mm, the capacitance between the collector and the rest of the detector may decrease (or increase) by perhaps 0.1 pF. If the collector is polarized at 300 V, this change in capacitance injects a spike of 30 pC into the electrometer. At the typical flame sensitivity, this spike is equivalent to a very narrow peak of half a pg, a readily detectable amount. The coaxial cable from the detector to the electrometer is also a capacitor sensitive to vibration. It also suffers from triboelectricity (charge... 

Fig. 8 Design features of a wide bore probe head for HPNMR (400 MHz) measurements. 1 O-ring 2 probe jacket 3 thermal insulation 4 polyvinyl chloride 5 O-ring 6 O-ring 7 semi-rigid coaxial cable 8 connection to thermostat 9 titanium tube 10 lid 11 screw 12 capacitor 13 capacitor holder 14 aluminium tube 15 upper plug 16 sample tube 17 saddle coil 18 -Macor 19 TiA16V4 vessel 20 lower plug 21 lower pressure screw 22 capacitor 23 coaxial cable and 24 capacitor holder.

Two types of coaxial transmission line are in common use today rigid fine and corrugated (semiflexi-ble) line. Rigid coaxial cable is constructed of heavy-waU copper tubes with Teflon or ceramic spacers. (Teflon is a registered trademark of DuPont.) Rigid line provides electrical performance approaching an ideal transmission line, including... 

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