Push-Pull Mode

In the push-pull mode, you can adjust the temperature of the heat sink T2 in any way you want. Is it better to keep the temperature difference (7j - T2) wide or narrow  

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Using the equivalency relationships in Table 3.1, propose an equivalent electrical circuit diagram for an enzyme thermistor operated (a) in direct detection mode and (b) in the feedback, push-pull mode. 

The numerator in equation (22-26) represents the processes occurring in the mobile phase, while the denominator represents the processes occurring in the stationary phase. Such a situation can be realized by combining a chiral stationary phase in a push-pull mode with a chiral mobile phase of opposite con-hguration, where two enantiomers of the chiral selector are involved, one for the chiral stationary phase and the other for the chiral mobile phase. The most selective chiral chromatographic system should be encountered when one enantiomer binds to the immobilized chiral selector in the stationary phase, whereas the other enantiomer predominantly associates with the chiral mobile-phase additive [158]. The above treatment is applicable to all applications regarding the use of chiral mobile phases. 

A hot fan (Fi) in Figure 2 acts in a push-pull mode to suck gases from the reactor and pressurize them to move through the circuits. The volume of recirculated gas through the heat exchanger-reactor loop is set by valve V2. The off-gas valve vy operates automatically in response to a pressure impulse line in the top of the reactor above the wood feed. This line provides a pressure signal referenced to ambient barometric pressure for adjusting to accomplish the desired pressure differential. Typically this is set at zero or minus 3.0 Pa to prevent wood gas escape... 

Specimens were strained in a push-pull mode by an Instron machine, Model TF-DM, which has cross head speeds from 0.05 to 0,5 cm/min and a load capability up to 10" kg. Details of the apparatus for the mechanical and electrical tests are reported elsewhere Only a brief description of the electrical portion is given here. The resistivity was measured by the typical four-probe dc method. A set of voltage leads were soft-soldered across the gauge length of the specimen surface. 

The eommon topologies whieh are eneompassed under this eategory are the buek, half-forward, push-pull, half and full bridge, with only the traditional voltage-mode eontrol method. Its representative eireuit diagram is given in... 

Figure 8-4 Signs of Core Saturation in the Push-Pull, with Voltage-Mode Control...

This detailed picture of the movement of the atom during manipulation was achieved with the aid of simulations [6]. The atom moves in a local potential minimum on the surface. This potential is the sum of the surface potential and the tip potential. The surface potential can be expressed by the migration barrier while the tip potential describes the direct interaction via chemical or electrostatic forces. The local potential minimum is not identical with the adsorption site, in the limit of close tip-atom separation this minimum always resides below the tip resulting in the sliding mode. The atom is slowly pushed/pulled by the tip out of the adsorption site until it jumps into the next local potential minimum. The jump to the next potential minimum proceeds on a timescale of picoseconds [7,8] whereas typical tip speeds are of the order of 0.5-2.5nm/s. 

A simple view of the mode of bonding of the carbon monoxide molecule to the surfaces of the transition metals and in their carbonyl complexes is well known and is thoroughly described in the literature.4 These metals have unfilled d-orbitals (or holes in their d-band), and the molecule in the linear form is held by a push-pull bond in which charge is transferred from the 5a orbital of the molecule into the metal s d-band, while there is back-donation of charge from the top of the d-band into the molecule s vacant... 

Other examples of [2+1] cycloaddition reactions with trifluoromethyl-substituted carbenes are known with carbenes bearing a halogen or a methoxy substituent, which seems to result in a push-pull stabilization.179-185 Yields depend on the mode of generation of the carbenes best yields of eyclopropanes tire obtained with carbenes generated from (polyfluorocthyl)mercury compounds.180- 84... 

As mentioned briefly, a recent contender to the hall of fame is the 5033, officially labeled a lOOV Push-Pull Voltage-Mode PWM controller, and released in 2003. Luckily, this analog vendor s datasheet only shows a Half-Bridge at work, and that we are aware is a good match for voltage-mode control. So I personally tend to think that marketing (alone) was responsible for this misleading push (or pull). 

Enzyme mechanisms can often avoid high-energy, unstable cationic or anionic intermediates that increase the reaction barrier. Triosephosphate isomerase catalyzes the tautomerization of the achiral dihydroxy acetone phosphate (DHAP) to f -glyceraldehyde-3-phosphate (G3P) by the mechanism shown below. Not only does the push-pull mechanism avoid forming a highly basic enolate, but the binding mode of DHAP determines which face of the enediol will be protonated in the second step, and therefore... 

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