Driven shield

Fio. 2. Experimental arrangement for measuring/< in semi-insulating materials. The sample is located in a Dewar between the magnet poles. E, vibrating reed electrometer R, recorder and digital data processor F, feedback-driven shields P, potential probes M, current meter. 

Figure 3.2.8. Driven shields (zero voltage drop between cable inner and shield).

Fig. 11.11 - Principle of a driven shield to minimise excessive capacitance to ground in the reference electrode lead.

A representation of the stratospheric system that shields terrestrial life from excessive solar ultraviolet radiation is presented in Figure 4. Our primary concern is the decrease of stratospheric ozone, most striking in the Antarctic, which has been linked to increases in CFCs from the troposphere, and the possible increased transport of these compounds between the stratosphere and the troposphere by increased temperature driven circulation. 

The second concern is the long response times that can result from typical cable and electrometer-input capacitances of 100 pF or more (RC = 1010 x 10 10 1 s). These capacitances can be effectively reduced by operating in a guarded mode, i.e., with the inner shield (say, in a triaxial cable system) driven at the same potential as that of the center conductor. (The Keithley... 

Similar to cell attachment, endosomal escape of simple lamellar complexes is a process driven by electrostatics [21, 25, 83] (see Sect. 2) and therefore inhibited by PEGylation. A strategy to recover efficient endosomal escape is to prepare PEG-lipids in which the PEG chains are attached via bonds that are quickly cleaved as the endosomal pH is lowered in the course of maturation. This practically converts the shielded complex back into an unshielded complex. Several acid-labile moieties have been investigated for similar purposes, e.g., hydrazones [92], vinyl ethers [93] and orthoesters [87, 94]. 

This electrokinetically driven micro mixer uses localized capacitance effects to induce zeta potential variations along the surface of silica-based micro channels [92], The zeta potential variations are given near the electrical double layer region of the electroosmotic flow utilized for species transport. Shielded ( buried ) electrodes are placed underneath the channel structures for the fluid flow in separate channels, i.e. they are not exposed to the liquid. The potential variations induce flow velocity changes in the fluid and thus promote mixing [92],... 

For HF steps protective neoprene gloves, apron, and a plastic face shield should be worn. For the low HF step, add up to 4 g of resin to one of the Kel-F reaction vessels that are a part of the HF apparatus, and add 37.5 mL of a mixture of 90% dimethylsulfide, 5% p-thiocresol, 5% p-cresol and chill with liquid nitrogen and draw over 12.5 mL of anhydrous HF using vacuum created with a water driven aspirator to make a 25% HF solution. Remove liquid nitrogen. 

In peaceful uses of nuclear reactions, electrical power plants can be driven by a nuclear reactor very close to criticality, with careful control of neutron flux excess heat from the well-shielded nuclear reactor is driven off by a liquid (H20, Na, or Hg), which in a secondary cycle or a tertiary cycle generates electricity by turning induction turbines. 

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