Electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) techniques for liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination of levonorgestrel were evaluated. In consideration of difference in ionization mechanism, the two ionization sources were compared in terms of LC conditions, MS parameters and performance of method. The sensitivity for detection...

We investigate discharge inception in air, in uniform background electric fields above and below the breakdown threshold. We perform 3D particle simulations that include a natural level of background ionization in the form of positive and − O2 ions. In background fields below breakdown, we use a strongly ionized seed of electrons and positive ions to enhance the field locally. In the region of ...

The low ionization state in parts of a sunspot may play an important role in its evolution and dynamical state. The cool magnetic interior region of the sunspot develops a substantial neutral atomic and molecular hydrogen osmotic pressure which can drive a wind outward from the umbra. Ambipolar diffusion against the magnetically pinned ionized plasma component can also distort the umbral magnet...

In this paper, we propose and investigate a schottky tunneling source impact ionization MOSFET (STSIMOS) with enhanced device performance. STS-IMOS has silicide (NiSi) source to lower the breakdown voltage of conventional impact ionization MOS (IMOS). There is cumulative effect of both impact ionization and source induced tunneling for the current gating mechanism of the device. The silicide so...

Laser-induced electron recollisions are fundamental to many strong field phenomena in atoms and molecules. Using the recently developed quantitative rescattering theory, we demonstrate that the nonsequential double ionization NSDI of atoms by lasers can be obtained quantitatively in terms of inelastic collisions of the target ions with the free returning electrons where the latter are explicitl...

ORJECI1VE: To evaluate the effect of copper-silver ionization on Legionella colonization and nosocomial legionnaires' disease and to compare the efficacy of metal ions versus the superheat-and-tlush method of disinfection. DESIGN: Prospective determination over a 36-month period of copper and silver ion concentrations in the recirculating hotwater system, Legionella colonization of the hospital...

Extremely high cut-off frequencies (1) with excellent noise performance demonstrate the capability of heterostructure field-effect transistors (HFET) based on the InAlAs/InGaAs/InP material system for microwave communication systems and for opto-electronic applications. But, due to the low energy band-gap of the channel material, at high drain-source-voltages VDS impact ionization in the channe...

We measure high resolution photoelectron angular distributions (PADs) for above-threshold ionization of xenon atoms in infrared laser fields. Based on the Ammosov-Delone-Krainov theory, we develop an intuitive quantum-trajectory Monte Carlo model encoded with Feynman's path-integral approach, in which the Coulomb effect on electron trajectories and interference patterns are fully considered. We...

The structures of the four lowest alanine conformers, along with their radical cations and the effect of ionization on the intramolecular proton transfer process, are studied using the density functional theory and MP2 method. The energy order of the radical cations of alanine differs from that of the corresponding neutral conformers due to changes in the basicity of the NH2 group upon ionizati...

We have run a set of experiments in the CLOUD chamber at CERN, Switzerland, studying the effect of dimethylamine (DMA) on sulfuric acid (SA)-water nucleation using a nitrate based Chemical Ionization Atmospheric Pressure ionization Time-Of-Flight Mass Spectrometer (CI-APiTOF). Experiment was designed to produce neutral high m/z SA-DMA clusters in close to atmospherically relevant conditions to ...