نتایج جستجو برای: ionization techniques
تعداد نتایج: 664290 فیلتر نتایج به سال:
Ionization mechanisms in the low-temperature thermal plasma, which contains alkali metal atoms as ionizable component and nanosized dust grains, are studied. In such a electrons captured by because work function of grains depends on their sizes, electron adsorption rate is more than thermionic emission for grains. Accordingly, an increase grain number leads to decrease volume ionization recombi...
Cross sections for the removal of both electrons of the hydrogen molecule by two photons are presented at 30 eV photon energy using the time-dependent close-coupling method. Our approach allows detailed information about the dynamics of the ionization process to be extracted, including angular distributions for the outgoing electrons. Analysis of our calculations reveals some similarities to th...
Background and Aims:Nowadays, many different techniques to extraction of chemical compounds from aquatic samples have been introduced, for examples techniques based on the use of needles that were packed with some sorbents. Considering that so far no synthesis sorbent based on single-walled carbon nanotubes and sol-gel techniques for the extraction of toluene and methyl ethyl ketone from ...
A flux of weakly interacting neutral particles incident on the Earth would produce occasional nuclear-recoil events in any material. These could be detected as scintillation or ionization pulses in suitable target materials. Expected rates are in the range 1-10(-4) events kg(-1) d(-1). These must be distinguished from much higher rates due to backgrounds from gamma and beta background, even in ...
Acid ionization in aprotic media is studied using Molecular Dynamics techniques. In particular, models for HCl ionization in acetonitrile and dimethylsulfoxide are investigated. The proton is treated quantum mechanically using Feynman path integral methods and the remaining molecules are treated classically. Quantum effects are shown to be essential for the proper treatment of the ionization. T...
Nanostructure-initiator mass spectrometry (NIMS) is a recently developed matrix-free laser desorption/ionization technique that has shown promise for peptide analyses. It is also useful in mass spectrometric imaging (MSI) studies of small molecule drugs, metabolites, and lipids, minimizing analyte diffusion caused by matrix application. In this study, NIMS and matrix-assisted laser desorption/i...
The misuse of the commonly used chemical diethylene glycol (DEG) has lead to many poisonings worldwide. Methods were developed for analysis of DEG and its potential metabolites; ethylene glycol, glycolic acid, oxalic acid, diglycolic acid and hydroxyethoxy acetic acid in human urine, serum and cerebrospinal fluid samples, collected following a DEG-associated poisoning in the Republic of Panama ...
In this study we evaluated a method for the characterization of complexes, formed in different relative ratios of mercury(II) to dicysteinyl tetrapeptide, by electrospray ionization orbitrap mass spectrometry. This strategy is based on previous successful characterization of mercury-dicysteinyl complexes involving tripeptides by utilizing mass spectrometry among other techniques. Mercury(II) ch...
Ab s tract. We report on the ionization states of -0.5-50 MeV/nucleon ions in the 6 November 1997 solar particle event using instrumentation on the SAMPEX satellite and the geomagnetic cutoff technique. Using the geomagnetic cutoffs of-10 MeV 'Ile and -20 MeV protons, we infer the ionization states of -0.5-50 MeV/nucleon C-Fe by measuring their latitude distributions. The geomagnetic cutoff met...
The approach of two different ionization techniques including electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was tested for the analysis of cholesteryl esters (CEs). The retention time (RT), signal intensity, protonated ion, and product ion of CEs were compared between ESI and APCI. RT of C...
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