Quadrupole mass filter acceptance in stability island created by double-frequency quadrupole excitation.

Increase in quadrupole mass filter resolution at separation in narrow band stability island (X-band) formed by biharmonic resonance excitation of ion oscillation is discussed. X-band and the normal working quadrupole mass filter modes are compared at theoretical resolution of 10,000 and different separation times. Transmission curves, acceptance ellipses parameters, and acceptance characteristics are obtained by numerical simulation.

Simulation of the simultaneous dual-frequency resonance excitation of ions in a linear ion trap.

The process of ion resonance dipolar excitation in a linear ion trap by 2 ejection waveforms with close frequencies is studied. The physical mechanism of increasing the resolving power using the ion excitation is a nonlinearity of the electric radio frequency fields caused by space charge. Using 2 resonance forces with 2 close frequencies leads to the completion of 2 excitation processes.

4D phase-space acceptance of the quadrupole mass filter.

Simulations of the four-dimensional (4D) phase-space acceptance volume of a quadrupole mass filter (QMF) are discussed. The 4D acceptance is considered since the ion trajectories in the X and Y phase planes are dependent via the initial RF phase at ion entry into QMF. The QMF parameters are set up for resolution equal to the ion mass number M.

Dipolar excitation in the third stability region.

Dipole resonant excitation of ions creates instability bands which follow iso-β lines where β is the characteristic exponent (stability parameter). Instability bands are exited most effectively on the fundamental frequency π= βΩ/2. Here π is the angle resonance frequency of the dipolar voltage applied to x or y pair rods of the analyzer, and Ω is the angle frequency of the main drive voltage.

Linear ion trap mass selectivity with impulse power supply and sinusoidal dipolar excitation.

Rationale: An ion trap mass analyzer can be operated by either a sinusoidal waveform power supply or an impulse waveform power supply. The optimal conditions for the performance of ion trap which is driven by an impulse waveform power supply with sinusoidal dipolar voltage were investigated theoretically, and further verified by experiments.

Methods: The analytical relationship between β and q values is derived theoretically for optimal performance, and the dependencies β(q) for different trapezoidal waveforms are studied.

Dipole Excitation: A New Method for Mass Analysis with a Quadrupole Mass Filter.

Trajectory calculations are used to investigate peak shapes and ion transmission with a proposed new method of mass analysis with a quadrupole mass filter. Dipole excitation is applied to either the x or the y electrodes, or both, to create bands of instability within the first stability region. With excitation between the y electrodes (near β y  = 0), ions are removed from the low mass side of a peak, and with ion excitation in x (near β x  = 1), ions are removed from the high mass side.

[The evaluation of hyperkineses in hepatocerebral dystrophy (Wilson-Konovalov disease) from the position of the theory of muscle spindles].

Objective: To obtain evidence for the possibility of considering hyperkineses in hepatocerebtal dystrophy from the position of the theory of muscle spindles.

Material And Methods: We examined 27 patients: rigid-arrhythmic-hyperkinetic form was diagnosed in 2 patients, trembling-rigid in 8, trembling in 16 and extrapyramidal-cortical in 1. Electromyography of different muscles in resting state and functional loadings taking into account surgical intervention was the main method of the study.

Quadrupolar ion excitation for radiofrequency-only mass filter operation.

Trajectory calculations are used to model a mass filter based on the radiofrequency (rf)-only operation of a linear quadrupole with resonant quadrupole excitation of ions (resonant excitation applied with the same spatial electric field as the main quadrupole rf field). Ions are not trapped, but pass continuously through the quadrupole. Excited ions gain axial kinetic energy in the fringe field at the quadrupole exit, overcome a stopping potential and are transmitted to an external detector.