Sensitizers charge effects

Rifle bullet sensitivity. About 60% of trials affected by 0.30 cal bullet fired at 90 ft, vs 92% affected for Pentolite Shaped charge effectiveness. Steel cone, hole volume 130% TNT... 

A triple-quadrupole mass spectrometer with an electrospray interface is recommended for achieving the best sensitivity and selectivity in the quantitative determination of sulfonylurea herbicides. Ion trap mass spectrometers may also be used, but reduced sensitivity may be observed, in addition to more severe matrix suppression due to the increased need for sample concentration or to the space charge effect. Also, we have observed that two parent to daughter transitions cannot be obtained for some of the sulfonylurea compounds when ion traps are used in the MS/MS mode. Most electrospray LC/MS and LC/MS/MS analyses of sulfonylureas have been done in the positive ion mode with acidic HPLC mobile phases. The formation of (M - - H)+ ions in solution and in the gas phase under these conditions is favorable, and fragmentation or formation of undesirable adducts can easily be minimized. Owing to the acid-base nature of these molecules, negative ionization can also be used, with the formation of (M - H) ions at mobile phase pH values of approximately 5-7, but the sensitivity is often reduced as compared with the positive ion mode. 

Besides the experimental data mentioned above, the kinetic dependencies of oxide adsorption of various metals are also of great interest. These dependencies have been evaluated on the basis of the variation of sensitive element (film of zinc oxide) conductivity using tiie sensor method. The deduced dependencies and their experimental verification proved that for small occupation of the film surface by metal atoms the Boltzman statistics can be used to perform calculations concerning conductivity electrons of semiconductors, disregarding the surface charge effect as well as the effect of aggregation of adsorbed atoms in theoretical description of adsorption and ionization of adsorbed metal atoms. Considering the equilibrium vapour method, the study [32] shows that... 

Since a minimum of about 100 ions is needed to generate a detectable signal under normal circumstances (ion counting is inherently more sensitive than image current detection) and space-charge effects become influential with more than 106 to 107 ions, the dynamic range is relatively poor, about 104. The same applies to the FTICR as to the QIT and orbitrap. The signal depends on other species present in the trap at the same time, which limits quantification quality. 

In general, non-spectral matrix issues appear to be a result of space charge effects, where for example, the sensitivity of an analyte decreases as the mass to charge ratio of a matrix element increases (Gillson et al. 1988 Praphairaksit and Houk 2000a). 

For a nuclide of mass M, abundance sensitivity is the ratio between the signal at mass M+ arising from the same species to the signal at mass M. Off-peak ions are present because of collisions behind the magnetic filter, of reflections on the tube wall, or of space-charge effects. As a result of the collisions, the energy of these ions is different from the energy of the main beam. They alter the apparent peak baseline in a continuous way. Abundance sensitivity decreases with the mean free path of ions, i.e., when pressure near the collector assembly... 

Mortar Projectile Test (7) Bomb Drop Test (7) Fragmentation Test (7-8) Fragment Velocity Test (8) Blast Effect (8) Shaped Charge Effectiveness (8) Hydrolysis by 240 Hour Test (9) Sensitivity to Initiation by Electrostatic Discharge (9 10)... 

A second important property of mass spectrometric separation systems is the abundance sensitivity. Even under sufficient vacuum conditions there is a scattering of ions in the beam by the residual gas. Furthermore, by scattering of particles by the wall of the analyzer tube or by electrostatic repulsion in the ion beam itself or charging effects, so-called peak tails in mass spectra are observed, which result in an increasing energy spread of ions and consequently in a deterioration in the abundance sensitivity. The abundance sensitivity of a mass spectrometer is defined as ... 

Drop Test. See Impact Sensitivity Test Effect of Pressure on Performance in Detonators. See Pressure Effect, etc Explosion(or Ignition) Temperature. When O.02g charges of pentryi were dropped on molten Wood s metal preheated to various temps, no expin or ignition took place at 233°(5 trials), but at 235° the sample ignited in 3 secs after it touched the hot surface. The same time interval was observed at 240°, while at 250° it was 2 secs, at 260° 1.5 to 2 secs and at 270—280° 1.5 secs (Ref 4,p 1389)... 

Fig. 6.21 Profiles of charge, electric field, and potential distribution through the gate of an ion-sensitive field-effect transistor (ISFET)...

The mass calibration law gives mass measurement accuracy of ca. 2 ppm and a precision of ca. 1 ppm. Errors are still systematic, but the measurements are much less sensitive to space charge effects than those made with the cubic cell. One possible cause of the systematic errors may be magnetic field inhomogeneity caused by... 

Chemical matrix effects due to space-charge ion transmission loss remain a problem. Concentrations of heavy ions as low as 100 ppm can affect sensitivity and therefore produce an analysis error. Perhaps alternative designs will reduce space-charge effects, but can the space-charge effects be significantly reduced while maintaining or continuing to improve sensitivity ... 

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