Stability region first

Figure 3.8 Stability diagram for a linear quadrupole mass analyzer, the first stability region showing a line scan. If the rf and dc voltages applied to the quadrupole are adjusted so that an ion mass m3 is inside the tip of the stability region, then heavier ions of mass m2 and m, and lighter ions m4 are outside the stability region and are filtered out.

This overlap, as displayed in Figure 2.16, shows common areas at different places. Commercial ion traps use the first stability region, which is circled and enlarged in the figure. 

Remark 5.1 It seems natural to conjecture that the linear stability regions in Theorem 5.3 coincide with the nonlinear stability regions. Theorem 5.1 gives the answer for part of the first increasing portion of the S-shaped curve in Figure 5. 

The first detailed data on the inversions of S1O2 were published in the classical studies by Fenner (1913, 1914) who used sodium tungstate as the mineralizer. As proved later, the use of the mineralizer affected the conclusions which had assumed tridymite to be a stable phase with a precisely defined stability region. The stability ranges of the Si02 phases, according to Fenner, are represented in the schematic equilibrium diagram in Fig. 4. 

Then, with a and q we can define a bi-dimensional space by which we can study the interdependence of the six parameters affecting the behavior of an ion inside the quadrupolar field. First, we can define the stability region of the quadrupole mass filter (i.e., the values of a and q for which the motion of the ions in the x and y direction (see Fig. 2.7) do not exceed the r0 value (in other words, the a and q values for which the ions do not crash on the rods ). 

Fig. 34 Cyclic voltammograms for Au(l 11)/0.05 M H2SO4 in the presence of 12 mM uracil, scan rate 10 mV s . The first scan as obtained with a flame-annealed, reconstructed electrode after immersion at —0.10 V is plotted as dashed line. The steady state voltammogram is shown as solid curve. The stability regions of the various adlayer phases are labelled I to IV, and they are illustrated with typical in situ STM images (a) thermally reconstructed Au(l ll)-(p x 3) surface, (b) physisorbed uracil film, (c) unreconstructed Au(lll)-(1 x 1) surface in the presence of the chemisorbed uracil film, (d) as obtained after scanning the electrode potential from II -> IV,...

Figure 3.9. First stability region for a quadrupole mass filter.

Example 3.4 Suppose that a quadrupole mass filter is operated at the tip of the first stability region, where the Mathieu parameters a and qu are equal to 0.237 and 0.706, respectively. If the maximum rf potential is 6000 V, the rf frequency is 0.5 MHz, and ro is 1.0 cm, what maximum miz value can be analyzed with this instrument ... 

This theoretical study gives rise to some practical conclusions. Firstly, to produce a stable source, the condition of initial stability of Eq. (5.64) must be achieved. Consequently, the parameter, determined from Eq. (5.58), should be as small as possible. All parameters in Eq. (5.58), except for S, are rigidly prescribed either by physico-chemical properties of the system or by standards for production and operatiOTi cmiditions. As to the area of the defect, where the cmitact of the oxidiser with lithium occurs (5 ), it depends, in the first place, oti the presence of impurities in Uthium, including mechanical ones. Therefore, the more pure the anode material is, the lesser is the probability of formation of the local source. Secondly, if the conditirm of Eq. (5.64) is satisfied, then, to get in the stationary stability region. Fig. 5.12, the K constant, determined from Eq. (5.55), should be as large as possible. An increase in piuity and the absence of mechanical impurities in lithium also promote this. Besides, the conductivity of local elements, determined as the product of k and the area of the separator pore section, should be maximum. 

Stability Region for the New Method with Vanished Phase-Lag and its First Derivative (Method NMI)... 

Figure 6.10 (a) The stability diagram for a two-dimensional quadrupole field in which the x- and y-directions differ by a factor of — 1. Reproduced from Dawson, Mass Spectrom. Revs. 5, 1 (1986), with permission, (b) Expanded view of the first stability region 1 (positive half only) in which both x- and y-motions are stable. The slope of the scan line a/q = is determined by... 

Similar derivation can also be applied to the r component (Equation 3.23), resulting in the relationships a = a = -2a and Qu = Qz r-Figure 3.5 displays the first overlapped stability region (gray area) in the plot. Unlike the two symmetrical triangular-shaped... 

Fig. 4.27) [86]. Among the four stability regions of the first category, region I is of special interest for the normal mass-separating operation of the linear quadru-pole(Fig. 4.28) [80,81]. 

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