Dwell times, measurement

The relative abundance of neutral SiH and H2 species have been measured as a function of power, pressure, flow rate, and dilution. For low power levels, eg, 5 W, up to 50% of the SiH gas is dissociated and the percentage increases to 80% for a power of 50 W. The decomposition of SiH gas proceeds more readily with lower flow rates. These observations, coupled with infrared (ir) measurements performed on the films, suggest that deposition under conditions in which the silane gas is not entirely decomposed leads to a majority of SiH units, whereas those deposited under conditions in which silane is strongly dissociated contain a majority of dihydride units leading to a deterioration of the semiconductor. Also, when the dwell time of SiH in the plasma region increases, the resultant film exhibits a pronounced peak at 2090 cm from the ir spectra corresponding to S1H2 inclusion. 

Probe tack. A probe (flat or not) is contacted with an adhesive film at a given pressure and dwell time. The force required to remove the probe from the adhesive is a measure of tack [30]. 

It can be shown that the standard deviation (SD) of this distribution is also just yfji. In other words, if one would repeatedly measure the same pixel that on average collects 100 photons during a single dwell time (a normal value for a rather bright confocal image ) one would record less than 100-2x /l00 = 80 photons or more than 100 + 2x /l00 = 120 photons just by coincidence in 5% of the measurements. This uncertainty is expressed as the... 

The dwell time is the time spent acquiring data at each of the channels which make up a peak in the mass spectrum. The length of time is measured in fractions of a millisecond, and will ultimately affect the frequency with which data is acquired at each mass. This will have a bearing on the final precision of the isotope ratio because of the influence of various sources of noise on the analytical signal. 

Force measurements made without displacement values are still useful in identifying the dependency of tablet hardness (and other associated characteristics) on compaction force, and also the effect of the tablet press compaction speed on tablet strength (influence of dwell time/effective... 

The punch pressure required to form a compact for tableting indices measurements is measured at the end of a long dwell time, typically 1.5 minutes, during which the punches remain in fixed positions and stress relaxation within the compact brings about a decay in the applied load. The reported pressure or CS is calculated from the relaxed force and it is dependent on the compact SF. A sample s CS at a standard SF, such as 0.85, can be interpreted to indicate the ease (i.e., the magnitude of the pressure) of forming compacts under standardized conditions. 

Cohesiveness, compactibility, and lubrication can be evaluated on research instrumented tablet presses, as discussed later. Such measurements should give a degree of assurance that the material will compress and eject properly. Only highspeed compaction sunulators or other equipment that controls dwell time, however, will give any indication of potential problems with high-speed presses. 

Some of these measurements can also be performed on compaction simulators, which are single-stroke presses specifically designed to evaluate individual materials and/or full formulations [ 12]. The simulation of short dwell times and of many different profiles for punch movement in real time are the advantages of this type of measurement. Recent work with a compaction simulator has even included a thermodynamic analysis of compaction [13,14]. 

Figure 25-30 Measurement of dwell time, using nonabsorbing solvent in reservoir A and a weak absorber in reservoir B. The gradient from 0 to 100% B is begun at time f = 0 but does not reach the detector until time fc. The column is removed from the system for this measurement. Real response will be rounded instead of having the sharp intersections shown in this illustration.

It is self evident that tack is very much influenced by the surface condition of the rubber as well as dwell time and pressure this includes contamination and the surface roughness of the test piece. Measurements should be distributed over a fairly large area of the rubber sheet in question to obtain representative results. 

The calculated times in Table 9.1 are for E = 25 kgf/cm and the measured ( ) times those given by Payne and Scott . (Payne and Scott did not make it absolutely clear that the times in question were measured.) The frequency can be taken as the reciprocal of twice the dwell time. In general, resilience is lower the higher the frequency but the Goodyear-Healey gave surprisingly... 

Tests on copper SRMs show that a stable signal is obtained when each isotope is measured using the peak jumping mode and one point per peak, with a dwell time of 25,000 ps. The quadrupole mass spectrometer scans three times the mass range per replicate and accumulates 10 replicates for a total acquisition time of about 1 minute. For this application, 22 isotopes were selected (Table I). 

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