Drift/mismatch

The alternating tendency of the copolymers is advantageous in that the polymerizations can be carried out to high conversions with little or no compositional drift. For random copolymerizations in which there is preferential incorporation of one monomer due to a mismatch in reactivity ratios, the compositional variations with conversion can be substantial. Such compositional heterogeneities in resist materials can lead to severe problems during image development. 

If the solvents are immiscible, the LC system will fail. If the pump will be delivering an eluent that is not soluble with the previous mobile phase or if the new mobile phase consists of two immiscible solvents, the net result is to have tiny slugs of different solvents traveling through the HPLC. Typical indications of this problem are (1) erratic flow rate, (2) noisy baseline, and/ or (3) baseline drift. To insure that these problems are not caused by a mismatch of solvents, refer to Table 6-4 for the miscibility numbers (M) and their use. The discussion on determining solvent miscibility using miscibility numbers is adapted from reference 20. 

A second issue is a mismatch between certain scan lines due to various effects, including vertical (Z) scanner drift, image bow, and skips. This effect can be eliminated by the operation called flattening. A first order flattening is a similar operation to the line by line planefit described in Sect. 2.1.1. 

Shock type Charging Resistor drift Material soft- Mismatch in Corrosion... 

Undefined delay times and distortion of the rise time reduce the derivable information of waveform analysis but the end-tidal value and the average value can be used clinically. Figure 23-24 presents an example of a flow mismatch with distortion of the CO waveform. The inspiratory value may be used to detect system failures. During the warm-up time and the subsequent Hrst hour, (he IR sensor typically shows increased drift and reduced accuracy until temperature balance is reached. Zero-point calibration can be effected periodically by automatically aspirating ambient air. Drifts of the measuring system are calibrated manually or automatically over longer periods by use of test gases. 

Over the four hour time period, the force produced can be seen to follow the oscillating reaction very closely, indicating that the diffusion through the gel is still quite fast relative to the timescale of the oscillations. The maximum force produced by the gel is 0.012N. The slight upward drift in the data is due to an increase in mass caused by a small mismatch between the flow rates of the pumps used. 

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