Mass analysis in islands of stability with linear quadrupoles with added octopole fields.

Mass analysis with linear quadrupole mass filters is possible by forming "islands" in the stability diagram with auxiliary quadrupole excitation. In this work, computer simulations are used to calculate stability boundaries, island positions, and peak shapes and ion transmission for mass analysis with linear quadrupole mass filters that have added octopole fields of about 2 to 4%. Rod sets with exact geometries that have quadrupole and octopole fields only in the potential, and round rod sets, with multipoles up to N = 10 (the twenty pole term) included in the calculations, show the same stability boundaries, island positions, and peak shapes.

Linear quadrupoles with added hexapole fields.

Linear quadrupoles with added hexapole fields are described. The shifts in ion oscillation frequency caused by the addition of a hexapole field are calculated within the effective potential model. Methods to construct linear quadrupoles with added hexapole fields with exact electrode geometries and with round rods are discussed.

Upper stability island of the quadrupole mass filter with amplitude modulation of the applied voltages.

Modulation of the voltages applied to a quadrupole mass filter (QMF), either RF or RF and DC, leads to splitting of the stability region into islands of stability. The ion optical properties, such as transmission, resolving power and peak tails of the first upper stability islands have been investigated by numerical simulation of ion trajectories. The dependence of the location of this island on the amplitude of the modulation and the parameter nu = omega/Omega = Q/P where omega is modulation frequency, Omega is main angular radio frequency, and Q and P are integers, is calculated in detail.

[Prospects for studies on morphological variability of land pulmonate snails].

The main goal of modern investigations into the morphological variability of land pulmonate snails was defined as designing the patterns of taxa structure on the basis of historical analysis of their taxonomic studies. Transition from the investigation of individual characters to an analysis of the organism as a whole assumes the application of the system approach. Systemic properties of the organism can be revealed through the key characters reflecting the process of evolutionary transformation of the correlation chains.

Matrix methods for the calculation of stability diagrams in quadrupole mass spectrometry.

The theory of the computer calculation of the stability of ion motion in periodic quadrupole fields is considered. A matrix approach for the numerical solution of the Hill equation and examples of calculations of stability diagrams are described. The advantage of this method is that it can be used for any periodic waveform.

Excitation frequencies of ions confined in a quadrupole field with quadrupole excitation.

Resonant quadrupole excitation of ions confined in a radio frequency quadrupole field with angular frequency omega by an excitation signal with angular frequency omega has been investigated theoretically. It is shown that the spectrum of excitation frequencies has considerable structure which corresponds to different orders of excitation. The resonance condition for orders K = 1,2,3,.

[Temperature dependence of the electrical activity of wasp cardiac function].

Changes in the temporal structure and amplitude of electrical fluctuations connected with the heart function were revealed by the electrophysiological method. In the range of optimum temperatures, high- and low-amplitude impulses are predominantly generated. Their amplitudes differ approximately by a factor of three.